Fraunhofer IBP - HEATING AND COOLING WITH FOCUS ON · 2020-08-08 · Application of exergy analysis into buildings has not been common before the implementation of Annex 37. Tools

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ESPOO 2004

Edited by Mia Ala-Juusela

VTT RESEARCH NOTES 2256

H E AT I N G A N D C O O L I N G W I T H F O C U S O NINCREASED ENERGY EFFICIENCY AND IMPROVED COMFORT

SUMMARY REPORT

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1

VTT RESEARCH NOTES 2256

Heating and Cooling with Focus onIncreased Energy Efficiency

and Improved ComfortGuidebook to IEA ECBCS Annex 37

Low Exergy Systems for Heating and Cooling of BuildingsSummary Report

2 LOWEXGUIDEBOOK

ISBN 951–38–6488–X (soft back ed.)ISSN 1235–0605 (soft back ed.)ISBN 951–38– 6489–8(http://www.vtt.fi/inf/pdf/)ISSN 1455–0865 (http://www.vtt.fi/inf/pdf/)Copyright © VTT 2004

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Edited by Mia Ala-Juusela, VTT , FinlandTechnical editing by Auli Rautakivi, VTT , FinlandLayout Auli Rautakivi & Mia Ala-Juusela, VTT based on the templete of Tuija Karppanen.

Edita Prima Oy, Helsinki 2004

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Espoo 2004. VTT Tiedotteita – Research Notes 2256KeyworKeyworKeyworKeyworKeywordsdsdsdsds exergy, heating, cooling

ABSTRACT

The Summary Report and Guidebook summarise the work of the LowEx cooperation. Another result of the LowEx cooperation was the funding of the International Society for LowExergy Systems in Buildings (LowExNet). LowEx, the international research programme forLow Exergy Systems for Heating and Cooling of Buildings, is part of the InternationalEnergy Agency's (IEA) Implementing Agreement Energy Conservation in Buildings andCommunity Systems (ECBCS). The aim of the programme was to promote rational use ofenergy by encouraging the use of low temperature heating systems and high temperaturecooling systems of buildings. These systems that are suitable for office buildings, servicebuildings and residential buildings, can use a variety of fuels and renewable energysources. These systems use energy efficiently while providing a comfortable indoorclimate. They should be widely implemented now in order to create a possibility to usesustainable energy sources in the near future.

This publication is an official Annex report. The Summary Report summarises and pre-sents the contents of the Guidebook, which is included here in CD-ROM format. TheGuidebook is meant to help engineering offices, consultants and architects in their searchfor energy efficient heating and cooling systems that can provide the occupants with com-fortable, clean and healthy environment. In addition, some background information is offer-ed for real estate builders, building maintenance managers, political decision makers andthe public at large. The Guidebook is also freely available on the internet (www.lowex.net).

Exergy defines the quality of energy and is an important tool for designing and assessingdifferent heating and cooling systems. Application of exergy analysis into buildings has notbeen common before the implementation of Annex 37. Tools for exergy analysis of buil-dings were developed during the working time of Annex 37 and are presented in the Sum-mary Report and included in the CD-ROM Guidebook. Exergy analysis can also be appliedto human body to find optimal thermal conditions. Studies show that the lowest humanbody exergy consumption occurs at thermally neutral condition. The findings suggest thatwe may be able to establish both thermal comfort and low-exergy consuming systems atthe same time. The human body exergy analyses have now just started to articulate whylow exergy systems are essential for creating rational and comfortable built environment.

In Annex 37, 'low exergy (or LowEx) systems' are defined as heating or cooling systemsthat allow the use of low valued energy as the energy source. In practice, this meanssystems that provide heating or cooling energy at a temperature close to roomtemperature. There are currently many low exergy technologies available. Low temperaturesystems successfully combine both traditional and innovative new approaches to heating.Usually the heat is transferred into the room through air or liquid circulation systems andthe same system can often be used for both heating and cooling.

Research shows that people living in houses with low temperature heating systems arevery satisfied with ambient indoor air quality. In particular, thermal comfort levels are con-sidered to be higher than in houses with a traditional heating system. Residents also ex-perienced a reduction in draughts and dust, and reported fresher air in houses with lowtemperature heating systems. The advantages and disadvantages, mentioned by theoccupants in the survey conducted during Annex 37, are similar to results in the literature.Also experiences from the case studies supported the findings from literature and theoccupants' survey.

By using low temperature heating systems the room temperature can be decreased by afew degrees, which is more energy efficient and healthier for occupants. Low temperature

ABSTRACT

4 LOWEXGUIDEBOOK

heating systems do not usually require radiators, which can be unsightly and hard to clean.This offers the additional advantages of increased living space and more flexibility in termsof interior design. Safety can also be improved during the heating season due to absenceof hot radiator surfaces.

The demonstration projects of Annex 37 show the wide variety of possibilities to apply lowexergy heating and cooling systems in buildings. There are examples of low exergysystems in dwellings and offices, but also in a museum and a concert hall.

The application of low exergy systems provides many additional benefits besides energysupply such as: improved thermal comfort, improved indoor air quality and reduced energyconsumption. These aspects should be further promoted to increase the application of lowexergy systems for heating and cooling of buildings. The building regulations and energystrategies should take the quality of enegry into account more than today.

Wide application of low exergy heating and cooling systems in buildings will create abuilding stock, which will be able to adapt to use of sustainable energy sources, whendesired. Without this ability, the transfer towards an energy-wise sustainable world will bedelayed for decades.

5

PREFACE

Annex 1: Load Energy Determination of Buildings (*)Annex 2: Ekistics and Advanced Community Energy

Systems (*)Annex 3: Energy Conservation in Residential Buildings (*)Annex 4: Glasgow Commercial Building Monitoring (*)Annex 5: Air Infiltration and Ventilation CentreAnnex 6: Energy Systems and Design of Communities (*)Annex 7: Local Government Energy Planning (*)Annex 8: Inhabitants Behaviour with Regard to Ventilation (*)Annex 9: Minimum Ventilation Rates (*)Annex 10: Building HVAC System Simulation (*)Annex 11: Energy Auditing (*)Annex 12: Windows and Fenestration (*)Annex 13: Energy Management in Hospitals (*)Annex 14: Condensation and Energy (*)Annex 15: Energy Efficiency in Schools (*)Annex 16: BEMS 1 - User Interfaces and System

Integration (*)Annex 17: BEMS 2 – Evaluation and Emulation Techniques (*)Annex 18: Demand Controlled Ventilation Systems (*)Annex 19: Low Slope Roof Systems (*)Annex 20: Air Flow Patterns within Buildings (*)Annex 21: Thermal Modelling (*)Annex 22: Energy Efficient Communities (*)Annex 23: Multi-zone Air Flow Modelling (COMIS) (*)Annex 24: Heat, Air and Moisture Transfer in Envelopes (*)Annex 25: Real time HVAC simulation (*)Annex 26: Energy Efficient Ventilation of Large Enclosures (*)

INTERNATIONAL ENERGY AGENCYThe International Energy Agency (IEA) was established in 1974 within the framework of theOrganisation for Economic Co-operation and Development (OECD) to implement an inter-national energy programme. A basic aim of the IEA is to foster co-operation among thetwenty-four IEA participating countries and to increase energy security through energyconservation, development of alternative energy sources and energy research,development and demonstration (RD&D).

ENERGY CONSERVATION IN BUILDINGS AND COMMUNITY SYSTEMS (ECBCS)The IEA sponsors research and development in a number of areas related to energy. Inone of these areas, energy conservation in buildings and community systems, the IEA issponsoring various exercises to predict more accurately the energy use of buildings, inclu-ding comparison of existing computer programmes, building monitoring, comparison ofcalculation methods, energy management systems as well as air quality, studies of occu-pancy and in depth evaluation of impact on energy consumption of the building enclosure.

THE EXECUTIVE COMMITTEEOverall control of the programme is maintained by an Executive Committee, which not onlymonitors existing projects but also identifies new areas where collaborative effort may bebeneficial. To date the following projects have been initiated by the Executive Committeeon energy conservation in buildings and community systems (completed projects areidentified by (*)):

Annex 27: Evaluation and Demonstration of DomesticVentilation Systems (*)

Annex 28: Low Energy Cooling Systems (*)Annex 29: Daylight in Buildings (*)Annex 30: Bringing Simulation to Application (*)Annex 31: Energy related Environmental Impact of

Buildings (*)Annex 32: Integral Building Envelope Performance

Assessment (*)Annex 33: Advanced Local Energy Planning (*)Annex 34: Computer-aided Evaluation of HVAC System

Performance (*)Annex 35: Design of Energy Efficient Hybrid Ventilation

(HYBVENT)(*)Annex 36: Retrofitting of Educational Buildings – REDUCE (*)Annex 37: Low Exergy Systems for Heating and Cooling of

BuildingsAnnex 38: Solar Sustainable HousingAnnex 39: High Performance Insulation SystemsAnnex 40: Building Commissioning to Improve Energy

PerformanceAnnex 41 Whole Building Heat, Air and Moisture

Response (MOIST-EN)Annex 42 The Simulation of Building-Integrated Fuel Cell

and Other Cogeneration Systems (COGEN-SIM)Annex 43 Testing and Validation of Building Energy

Simulation ToolsAnnex 44 Integrating Environmentally Responsive Elements

in Buildings

PREFACE

6 LOWEXGUIDEBOOK

ACKNOWLEDGEMENTS

The material presented in this publication has been collected and developed within anAnnex of the IEA Implementing Agreement Energy Conservation in Buildings andCommunity Systems (IEA ECBCS), Annex 37 "Low Exergy Systems for Heating andCooling of Buildings" (LowEx).

The Summary Report and the Guidebook are the result of a joint effort of many countries.All those who have contributed to the project by taking part in the writing process or thenumerous discussions, are gratefully acknowledged. A list of the 11 participating countrieswith central contacts can be found in part A. In addition, Greece and Slovenia participatedin form of a couple of case studies considering LowEx applications in existing (LowExx)buildings, collected in a special LowExx project. The contact information of the participantsof the LowExx project can be found on the CD as well as an extended list of participatinginstitutes and individuals of Annex 37. The participating countries have all contributed tothe Guidebook by collecting information in their own countries. However, some of theAnnex participants have taken the responsibility of collecting the information or writing thechapters in the Guidebook. They are

Mia Ala-Juusela, VTT, Finland (editor, Subtask D coordinator)Claude Francois, CSTB, France (especially chapter 3)Abdelaziz Hammache, NRCan, Canada (especially chapter 2 and 3.2)Koichi Isawa, Musashi Institute of Technology, Japan (chapter 2)Gudni Jóhannesson, KTH, Sweden (especially chapter 4, Subtask B coordinator)Alain Legault, NRCan, Canada (Subtask A coordinator)Åsa Nystedt, VTT, Finland (co-editor, Subtask D coordinator 2002)Peter Op't Veld, CH, The Netherlands (especially chapter 5, Subtask C coordinator)Paul Ramsak, Novem, the Netherlands (especially chapter 5.4.3)Masaya Saito, Cornell University, USA (chapter 2)Dietrich Schmidt, KTH, Sweden (important contribution to almost every chapter)Masanori Shukuya, Musashi Institute of Technology, Japan (especially chapter 2)Carey Simonson, University of Saskatchewan, Canada (Operating Agent 2001)Markku Virtanen, VTT, Finland (Operating Agent 1999-2000 and 2002-2004)Johann Zirngibl, CSTB, France (especially chapter 3)

On behalf of all participants, the members of the Executive Committee of IEA ECBCS aswell as the funding bodies are also gratefully acknowledged.

Per Heiselberg, the editor of IEA ECBCS Annex 35 Final report is gratefully acknowledgedfor providing an outstanding example of how to compile an interesting-looking and yetcomprehensive Guidebook.

7 CONTENTS

CONTENTS

ABSTRACT ......................................................................................3

PREFACE ........................................................................................5

ACKNOWLEDGEMENTS .................................................................6

CONTENTS .....................................................................................7

1. INTRODUCTION ..........................................................................8How to use the Guidebook ................................................................................................ 8About the Annex 37 ............................................................................................................ 9Energy, exergy and environment ...................................................................................... 11Why exergy approach? ..................................................................................................... 11Historical overview on exergy concept ............................................................................ 12

2. THE EXERGY APPROACH ........................................................13Introduction to the concept .............................................................................................. 14Difference between energy and exergy analysis ............................................................. 15The human body consumes exergy for thermal comfort ................................................ 16

3. ANALYSIS TOOLS FOR THE EXERGY CHAIN...........................19Educational exergy analysis tool for heating ................................................................... 20Pre-design tool for heating and cooling .......................................................................... 22

4. CONCEPTS AND TECHNOLOGIES ..........................................24Summary table of the LowEx technologies ..................................................................... 24LowEx system concepts .................................................................................................. 27Strategies for design of low exergy systems in buildings ............................................... 30

5. EXAMPLES OF LOWEX BUILDINGS .........................................31Summary table of case studies ........................................................................................ 31Retrofits ............................................................................................................................. 33Advantages and limitations of low exergy systems ........................................................ 34

6. MARKET POSSIBILITIES ...........................................................38

7. STRATEGIES AND POLICIES ....................................................40

8. CONCLUSIONS .........................................................................41

9. REFERENCES ...........................................................................43

A. PARTICIPATING COUNTRIESB. COMPANY AND PRODUCT INFORMATIONC. ADDITIONAL INFORMATIOND. PUBLISHED ARTICLES

8 LOWEX GUIDEBOOK

The Guidebook is intended to be usefulfor architects and engineers designingheating and cooling systems of buildings. Adatabase of low exergy components iscompleted with the guidelines for selectionof products (in Chapter 4). Examples ofsystem concepts for different buildings andclimates are presented (in Chapter 5) aswell as a set of tools for analysis (describedin Chapter 3, included in the CD-ROM). Allthis is expected to be helpful forengineering offices, consultants andarchitects in their search for energy efficientheating and cooling systems that canprovide the occupants with comfortable,clean and healthy environment.

An analysis of case studies (in Chapter 5)together with rationale of exergy concept(in Chapter 2) and recommendationsconcerning regulations in building sectorand energy tariffs (in Chapter 7) areexpected to be helpful for real estatebuilders, building maintenance managers,political decision makers and the public atlarge. The description of the current marketsituation (in Chapter 6) offers the readeradditional background information aboutthe situation in different countries.

1. INTRODUCTION

This publication is a Summary

Report presenting and

summarising the contents of the

LowEx Guidebook (referred to as

Guidebook in this publication),

which is attached to this Summary

Report as a CD-ROM.

The Guidebook is the achievement

of the work done in the IEA

ECBCS Annex37 “Low exergy

systems for heating and cooling of

buildings”. The Guidebook is

available as a CD-ROM version

and also freely available on the

internet (http://www.lowex.net).

Since many readers prefer to just

print out the whole thing at once,

you can choose to open the

Guidebook as a pdf-version and

print it out. The CD-ROM version,

however, offers a more user

friendly environment and some

additional information.

The CD-ROM version of the Guidebookincludes the same information as theprintable version, but it offers the usersome additional opportunities in movingaround in the Guidebook. Through the“Annex 37 Countries” page the user hasaccess to the country specific information,like the national contact persons and caseexamples as well as the climate andhousing standards. The country specificpages also include information about thecompanies that provide services in theLowEx field and are located in the countryin question. There is a link to the country’sMarket Analysis and Strategies and Policieschapters. From the summary tables of theLowEx technologies and the caseexamples, the user can choose projects ortechnologies matching certain criteria.There is a link from the technologies tableto the case examples, where thesetechnologies have been used and viceversa. We have also collected someAdditional Information to the CD-ROM. Thisincludes the Technical reports written forthe ECBCS ExCo, the LowEx Newsletters,an English Brochure, the publication called“Introduction to Exergy”, published articlesetc.

Figure 1. The final results of Annex 37 are presented in many formats.

HOW TO USE THE GUIDEBOOK

9INTRODUCTION

ABOUT THE ANNEX 37

BACKGROUND“Energy saving” and emission reduction

are both affected by the energy efficiencyof the built environment and the quality ofthe energy carrier in relation to the requiredquality of the energy. Taking into accountqualitative aspects of energy leads tointroduction of the exergy concept incomparison of systems, which is the keyidea of Annex 37. Exergy is energy, whichis entirely convertible into other types ofenergy. High valued energy such aselectricity and mechanical workloadconsists of pure exergy. Energy, which hasa very limited convertibility potential, suchas heat close to room air temperature, islow valued energy. Low exergy heating andcooling systems allow the use of lowvalued energy, which is delivered bysustainable energy sources (e.g. by usingheat pumps, solar collectors, eitherseparate or linked to waste heat, energystorage etc.). Common energy carriers likefossil fuels deliver high valued energy. Thereason for “energy saving” being inquotation marks in the first sentence, isthat we actually are talking about savingexergy, not energy!

Figure 2. The transition from highvalued energy sources to low valuedenergy sources requires appropriateheating and cooling systems inbuildings. Heating and coolingsystems that provide heating or coolingenergy at a temperature close to roomtemperature (i.e., low exergy or LowExsystems) are a prerequisite for theefficient utilisation of low valued energysources. On the other hand, theefficiency of high valued energysources is less dependent on theheating and cooling systems inbuildings.

LowEx, the international low

temperature heating systems

research programme (IEA ECBCS

Annex 37), is part of the

International Energy Agency’s (IEA)

Energy Conservation in Buildings

and Community Systems

programme (ECBCS). The aim of

the programme was to promote

rational use of energy by

encouraging the use of low

temperature heating systems and

high temperature cooling systems

of buildings. In Annex 37 these

systems are called low exergy (or

LowEx) systems.

Future buildings should be planned to useor to be suited to use sustainable energysources for heating and cooling. Onecharacteristic of these energy sources isthat only a relatively moderate temperaturelevel can be reached, if reasonably efficientsystems are desired. The development oflow temperature heating and hightemperature cooling systems is a necessaryprerequisite for the usage of alternativeenergy sources. The basis for the neededenergy supply is to provide occupants witha comfortable, clean and healthyenvironment.

LOWEX SYSTEMSIn Annex 37, 'low exergy (or LowEx)

systems' are defined as heating or coolingsystems that allow the use of low valuedenergy as the energy source. In practice,this means systems that provide heating orcooling energy at a temperature close toroom temperature.

1 0 LOWEX GUIDEBOOK

OBJECTIVE AND SCOPEThe general objective of the Annex 37

was to promote rational use of energy bymeans of facilitating and accelerating theuse of low valued and environmentallysustainable energy sources for heating andcooling of buildings.

The interest of the Annex 37 covers alltypes of buildings. Both new and retrofittedbuildings are considered. Attention is paidto the impact of the building on the wholeenergy chain. The building is regarded as asystem. Life cycle aspect andenvironmental impacts of systems arediscussed. End users point of view andbehaviour are taken into account.

STRATEGYFour subtasks were carried out in order

to reach the objectives:- Subtask A: Exergy Analysis Tools for

the Built EnvironmentTools were developed to enable anassessment of low exergytechnologies, components andsystems.

- Subtask B: Low Exergy Concepts andTechnologiesA database of low exergy componentswas created, and the advantages,requirements and limitations of thecomponents were assessed.

- Subtask C: Case Studies and MarketPotentialsPractical experiences gained from theinstalled low exergy systems werecollected and the market possibilities oflow exergy systems in differentcountries were analysed.

- Subtask D: Documentation andDisseminationThe Annex research results werecompiled and disseminated. Means ofinfluencing the energy policies andregulations in order to promote the useof low exergy systems were looked for.

Figure 3a and b. The scope of Annex37 covers both environmental impactsof the systems and the end user’s pointof view. Both new and retrofittedbuildings are considered.

1 1INTRODUCTION

ENERGY, EXERGY AND ENVIRONMENT

WHY EXERGY APPROACH?

The necessity for an increase in

the efficiency of energy utilisation in

buildings is obvious and

indisputable. Heating, cooling and

lighting appliances in buildings

cause more than one third of the

world’s primary energy demand

(ECBCS 2002). Thus, the building

stock contributes as a major actor

to the energy related

environmental problems.

What we really should start talking about,because this is what we actually mean, is“saving exergy” and “exergy consumption”.This is more explained in chapter 2. Themore you learn about exergy, the moreabsurd it feels like to talk about energy -when we actually mean exergy.

Why couldn’t we use the primary energyapproach? If we always took into accountthe primary energy needed to performsomething, we would get far better resultsin our energy-analyses; with that perspec-tive it would be clear that 1 kWh doesn’talways mean the same thing as another1 kWh. One reason for using the exergyapproach and not just settling for theprimary energy approach is that it is physi-cally more correct to talk about exergy-than energy consumption and production.

It is a fact that the term “exergy” is anunknown term even for scientists not tomention “people on the street”. In order tomake this term less “strange” we need tofirst of all start talking more about it andstop using the term energy when weactually mean exergy. The publication“Introduction to the Concept of Exergy- fora Better Understanding of Low Tempera-ture Heating and High Temperature CoolingSystems” that has been published bymembers of the Annex 37 group, gives theterm exergy a clear explanation. Bydisseminating this publication widely wecontribute to making the term more known.Most of the contents of this publication canbe found in chapter 2 of the Guidebook.

According to the first law of

thermodynamics, energy can’t be

conserved or used, it can only

change forms. Thinking about this

first law, makes you wonder how

we can be talking about “saving

energy” or “energy consumption” if

it can’t be saved or consumed!

The growing concern of environmentalproblems, such as global warming, whichhave been linked to the extended use ofenergy, has increased both the importanceof all kinds of so called "energy savingmeasures", and the necessity for anincreased efficiency in all forms of energyutilisation. Despite the efforts made toimprove energy efficiency in buildings, theissue of gaining an overall assessment, andcomparing different energy sources stillexists. Today’s analysis and optimisationmethods do not distinguish between diffe-rent qualities of energy flows during theanalysis. An assessment of energy flowsfrom different sources is first done at theend of the analysis by weighting them withthe primary energy factors. The primaryenergy factors necessary for the calculationare not based on analytical ground orthermodynamic process analyses, yet theyhave been derived from statistical materialand political discussion (DIN 4701-102001).

In the theory of thermodynamics, theconcept of exergy is stated to be the maxi-mum work that can be obtained from anenergy flow or a change of a system. Theexergy content expresses the quality of an

energy source or flow. This concept can beused to combine and compare all flows ofenergy according to their quantity andquality. Exergy analysis is commonly usedin, for example, the optimisation processesof power stations. This method can beapplied to buildings, as well. Most of theenergy is used to maintain room tempera-tures at around 20 °C. In this sense,because of the low temperature level, theexergy demand for applications in roomconditioning is naturally low. In most cases,however, this demand is satisfied with highquality sources, such as fossil fuels or usingelectricity. Exergy analysis provides us withadditional information on where and whenthe losses occur. It helps us to see in whichpart of the energy chain the biggest savingscan be achieved. (Schmidt 2004)

The need for energy saving is based onthe will to reduce the effects of our actionsto the environment. The negative environ-mental effects of energy production aremainly due to the use of fossil fuels. Whenall energy will be produced with renewableenergy sources, then it becomes lessinteresting to save exergy. This is why wealso want to include solar energy to oursources, even if it is a high exergy source.

1 2 LOWEX GUIDEBOOK

The method of exergy analyses,

based on the second law of

thermodynamics and the

irreversible production of

entropy, is neither new nor

modern. The early fundamentals

were already stated by Carnot in

1824 and Clausius

in 1865 (Ahern 1980).

Figure 4a and b. The parish churchSt Tilen in Mokronog, Slovenia wasbuilt in 1824, the same year Carnot firststated the fundamentals for exergy. Inits renovation in 1999, a low exergyheating system was installed. Projectwas led and monitoring of walltempering system was realised byBuilding and Civil Engineering InstituteZRMK (Malovrh and Praznik 2002).

HISTORICAL OVERVIEW ON EXERGY CONCEPT

Even though modern textbooks on ther-modynamics (Moran and Shapiro 1998)and lecture notes for university studentsinclude chapters on the second law of ther-modynamics and the concept of entropyand exergy, the practical use of these con-cepts has been very limited. Energy relatedsystems are designed and their performan-ce is evaluated mainly by using the energybalance of the first law of thermodynamicsalone. An example of this is the newlyestablished German energy conservationregulation EnEV, in which the overall sys-tem performance and the assessment ofenergy flows from different sources areevaluated from the calculated amount ofthe primary energy use (Maas et al. 2002).

Although exergy analysis is not beingwidely used, there is a growing concernabout the second law of thermodynamicsin reports and books, which promote theuse of this named method. Yet, due todifficulties and the complexity of theseconcepts, there still seems to be a lack ofacceptance amongst engineers (Ahern1980). Intensive literature studies havebeen carried out, showing the advantagesof the proposed method (Cornelissen1997, Wall 1986 and Ahern 1980).

The method of exergy analyses has beenprimarily developed in Europe, especially inGermany, Poland and the former SovietUnion. The term "exergy", first used by

Rant in 1956, has been connected to thecapability to do work or the available workfrom a process, and the Carnot efficiencyof thermal systems. Baehr used the met-hod for the analyses of power stations in1965 and provided several examples ofexergy calculations. He presented analyti-cal results by comparing flowcharts ofexergy analyses with energy calculationsbased on the first law of thermodynamics.The results clearly show the significantdifferences obtained by these two methodsof analysis (Ahern 1980).

The discussed references are just a smallportion of the literature to be found on thesecond law of thermodynamics andalthough engineers and physicists havebeen studying this subject since Carnot’sdays, it is still under controversial andambitious discussion (Ahern 1980). Thetexts available (Wall 1986, Cornelissen1997) indicate the strong belief of theauthors that exergy analysis and theapplication of the second law of thermo-dynamics are important aspects in desig-ning and evaluating all energy systems. Asthe concern about questions and prob-lems regarding the efficient use of energy isgrowing, pioneering efforts made in thepast should be extended and implementedto commonly used methods for engineer-ing system design and performance analy-sis. The simplicity of the exergy analysismethod might help in reaching this goal(Ahern 1980).

In case of building applications, only afew papers, mainly from Japanese(Shukuya 1994, Asada and Shukuya 1999,Nishikawa and Shukuya 1999) and German(Baehr 1980, Gertis 1995, Steimle 2000,Klemp 1997, Jenni and Hawkins 2002)research teams, have been published.Annex 37 working group continued thedevelopment of the use of exergy conceptin connection with buildings and makingthe exergy concept more understandableand familiar to the public.

From an article by Schmidt (2004).

THE EXERGY APPROACH 13

Today calculations of energy use inbuildings are based solely on the energyconservation principle, the first law ofthermodynamics. As shown in chapter 2 ofthe Guidebook, through analyses andexamples, the energy conservationconcept alone is not adequate enough togain a full understanding of all theimportant aspects of energy utilisationprocesses. From this point of view, themethod of exergy analyses based on acombination of the first and second law ofthermodynamics is presented, as themissing link needed to fill the gap inunderstanding and designing energy flowsin buildings.

The basic principles for exergy analysishave already been stated in the nineteenthcentury, but the term exergy was firstintroduced in the mid-1950s. The differ-ence between energy and exergy analysisis explained with examples in chapter 2.3of the Guidebook.

By typical cases of heating and cooling,the advantages of exergy analysis areshown. The calculation examples inchapters 2.9- 2.10 of the Guidebooksuggest that to achieve an exergyoptimised building design, loads on the

2. THE EXERGY APPROACH

Chapter 2 in the Guidebook

describes the general

characteristics of a thermodynamic

concept, exergy, which enables us

to articulate what is consumed by

all working systems, whether they

are man-made systems, such as

thermo-chemical engines, or

biological systems including the

human body. The chapter focuses

especially on its application to

describing building heating and

cooling systems. An example is

given about the possibilities of

exergy analysis to find the

boundary conditions for thermal

comfort of the human body. In this

Summary Report, the basic

concept is described, followed by

an example, which helps to

understand the difference between

energy and exergy analyses.

Summary of the human body

exergy analysis example is also

given.

building service system have to be reducedas much as possible. First after that, in agood building shell, further improvementson the building service system seem to bemeaningful. Therefore, rational passivedesign seems to be a prerequisite ofrealising low exergy systems for heatingand cooling of buildings.

The human body exergy analyses havenow just started to articulate why lowexergy systems are essential for creatingrational and comfortable built environment.Examples of human body exergy analysisare presented in chapter 2.11 of theGuidebook.

Figure 5a and 5b. All working systems, biological or manmade, consume exergy.

14 LOWEX GUIDEBOOK

When we use such expressions as“energy consumption”, “energy saving”,and even “energy conservation”, weimplicitly refer to “energy” as intenseenergy available from fossil fuels or fromcondensed uranium. But, it is confusing touse one of the most well-establishedscientific terms, energy, to mean “to beconserved” and “to be consumed” simulta-neously. This is why we need to use thethermodynamic concept, exergy, toarticulate what is consumed.

ACTIVE AND PACTIVE AND PACTIVE AND PACTIVE AND PACTIVE AND PASSIVE SYSTEMSASSIVE SYSTEMSASSIVE SYSTEMSASSIVE SYSTEMSASSIVE SYSTEMSOver the last two decades various so-

called “energy saving” measures havebeen conceived, developed, and imple-mented in building envelope systems andalso their associated environmental controlsystems such as lighting, heating, andcooling systems. Those measures can becategorised into two groups: those for“passive” systems and those for “active”systems (Figure 6).

“Passive” systems are defined asbuilding envelope systems to make use ofvarious potentials to be found in theimmediate environment such as the sun,wind, and others to illuminate, heat,ventilate, and cool the built environment.

“Active” systems are the systems

consisting of various mechanical andelectric components such as fans, pumps,heat pumps, and others, all of which workby the use of fossil fuels. Most of the activesystems available these days have beendeveloped with an assumption of theabundant use of fossil fuels so that they donot necessarily work in harmony withpassive systems.

LOW EXERGY SYSTEMSLOW EXERGY SYSTEMSLOW EXERGY SYSTEMSLOW EXERGY SYSTEMSLOW EXERGY SYSTEMSLow temperature heating systems are

such kind of “active” heating systems thatshould fit the built environment to beconditioned primarily by “passive” heatingsystems. A good thermal-environmentalcondition within built spaces in the winterseason can be provided basically with theinstallation of thermally-well-insulatedbuilding materials with appropriate heatcapacity, which make it possible to utiliseheat sources of lower temperature forheating.

In summer season, a moderate thermal-environmental condition within built spacesmay be provided with a combination ofnocturnal ventilation, the installation ofappropriate shading devices for glasswindows, and the reduction of internal heatgain in addition to the use of thermally-wellinsulating materials with appropriate heatcapacity for building envelopes. This wouldallow the utilisation of cold sources withhigher temperature for cooling.

The use of the exergy concept in describ-ing various heating and cooling systems,whether they are passive or active, wouldenable us to have a better picture of whatlow temperature heating and high tempera-ture cooling systems are.

From Shukuya and Hammache (2002)

Figure 6. The LowEx case building”IDIC” in Iwate,Japan has both active and passive systems forenvironmental control, (see case JPN 5 in theGuidebook).

People often claim that energy is

consumed; this is not only in

everyday conversation but also

even in scientific discussion

associated with so-called energy

and environmental issues. This

claim, however, conflicts with the

first law of thermodynamics stating

that the total amount of energy is

conserved even though forms of

energy may change from one to

another.

I N T R O D U C T I O N T O T H E C O N C E P TI N T R O D U C T I O N T O T H E C O N C E P TI N T R O D U C T I O N T O T H E C O N C E P TI N T R O D U C T I O N T O T H E C O N C E P TI N T R O D U C T I O N T O T H E C O N C E P T


DDDDD I F F E R E N C E B E T W E E N E N E R G Y A N D E X E R G Y A N A LI F F E R E N C E B E T W E E N E N E R G Y A N D E X E R G Y A N A LI F F E R E N C E B E T W E E N E N E R G Y A N D E X E R G Y A N A LI F F E R E N C E B E T W E E N E N E R G Y A N D E X E R G Y A N A LI F F E R E N C E B E T W E E N E N E R G Y A N D E X E R G Y A N A LY S I SY S I SY S I SY S I SY S I S

Simple examples can help to

enhance the understanding of the

differences in energy and exergy

analyses.

A large enclosure with adiabatic bounda-ries containing a lot of air at the initialtemperature of Ti and a small container offuel are shown in Figure 7. It is furthermoresupposed that the fuel burns in air, heatingthe surrounding air and environment so thatthere is a slightly warm mixture of combus-tion products and air in the final state. It isobvious that the total quantity of energy inthe enclosure is the same as in the initial

state. But the combination of fuel and air inthe initial state has a greater potential to beuseful than the warm mixture in the finalstate. The fuel can be used in a device togenerate electricity, do work or heat rooms.But the uses for the slightly warm combus-tion products are much more limited. It canbe stated that the initial potential has beendestroyed to a large extent (Moran andShapiro 1998).

Figure 7. Combustion of fuel in air as an example to show the difference between energy and exergyanalysis (Moran 1989, modified).

Figure 8. Both systems contain the same amount of energy but not the same amount of exergy.

The same fact, that there is an energyquality, can be illustrated by anotherexample evident for us from our experiencein daily life (Figure 8).

It is obvious that 100 kJ electricity storedin a 12 V / 2.3 Ah car-battery is moreuseful, easier to transform into somethinguseful for us, than the same amount ofenergy stored in 1 kg water at a tempera-ture of 43 °C in an ambient temperature of20 °C. The electricity is suitable for running

a machine, like a computer, operating alight bulb of 40 W for 42 min or at leastheating 1 kg of water with 23 °C. The100 kJ heat contained in the 1 kg water isonly suitable for washing our hands ordoing the dishes. It becomes clear thatthere is a difference between the types ofenergy. By introducing the term exergy weappreciate the fact that energy manifestsitself by its quantity and its quality (Schmidt2001).

16 LOWEX GUIDEBOOK

We humans feed on exergy contained byfood, and thereby consume it within ourbody so that we can sense, think andperform any physical work by contractingour muscles. In due course, we inevitablyproduce entropy, and it must be discardedinto the built environment as symbolicallyshown in Figure 9.

Heating and cooling systems in buildings,whether they are active or passive, alsowork as exergy-entropy processes. This iswhat thermodynamics tells us. “Exergy” isthe concept to articulate what is consumedwithin a system, and “entropy” is what isdisposed of as waste from the system. Inother words, exergy is the concept thatquantifies the ability of energy and matterto disperse, and entropy is the conceptthat quantifies how much energy andmatter are dispersed.

EXERGY BALANCE OF THE HUMANEXERGY BALANCE OF THE HUMANEXERGY BALANCE OF THE HUMANEXERGY BALANCE OF THE HUMANEXERGY BALANCE OF THE HUMANBODYBODYBODYBODYBODY

It is vitally important to have a clearimage of the exergy balance of the humanbody in order to understand what the lowexergy systems for heating and cooling inbuildings are. Therefore a mathematicalmodel of the human body exergy balancewas developed and its numerical calcula-

As explained in chapter 2.2. of the

Guidebook, the exergy-entropy

process of any working system

consists of the following four

fundamental steps: The systems

first feed on exergy and then

consume a portion of it or all of it

to perform their purposes while at

the same time producing entropy

as the result of exergy consump-

tion, and finally they discard the

produced entropy into the

environment. The human body,

which occupies the built environ-

ment controlled by heating and

cooling systems, is no exception.

tion was made and the result was related tohuman thermal sensation (Saito andShukuya 2000).

EXAMPLE OF HUMAN BODY EXERGYEXAMPLE OF HUMAN BODY EXERGYEXAMPLE OF HUMAN BODY EXERGYEXAMPLE OF HUMAN BODY EXERGYEXAMPLE OF HUMAN BODY EXERGYCONSUMPTIONCONSUMPTIONCONSUMPTIONCONSUMPTIONCONSUMPTION

Figure 10 shows one of the results of thenumerical calculation assuming a thermallysteady-state environmental condition (Saitoand Shukuya, 2000; Saito et al 2002). Thisis the relationship between the warm andwet exergy-supply rate (input), the exergyconsumption rate, the rate of exergystorage, the rate of exergy output fromhuman body and the environmentaltemperature with the correspondingthermal sensation (PMV*).

Exergy consumption within the humanbody becomes higher in a cold environ-ment due to larger difference in tempera-ture between the human body and itssurrounding space and also becomeshigher in a hot environment mainly due tosweating.

It is interesting that the thermally comfort-able condition is provided with the lowestexergy consumption rate within the humanbody. This suggests that rational heatingand cooling systems in buildings wouldwork well with low exergy consumption

Figure 9. The human body works as anexergy-entropy process.

The general form of exergy balance equation of a system is described as follows.The general form of exergy balance equation of a system is described as follows.The general form of exergy balance equation of a system is described as follows.The general form of exergy balance equation of a system is described as follows.The general form of exergy balance equation of a system is described as follows.Input Exergy – Exergy Consumed = Stored Exergy + Output Exergy

T H E H U M A N B O D Y C O N S U M E S E X E R G Y F O R T H E R M A L C O M F O RT H E H U M A N B O D Y C O N S U M E S E X E R G Y F O R T H E R M A L C O M F O RT H E H U M A N B O D Y C O N S U M E S E X E R G Y F O R T H E R M A L C O M F O RT H E H U M A N B O D Y C O N S U M E S E X E R G Y F O R T H E R M A L C O M F O RT H E H U M A N B O D Y C O N S U M E S E X E R G Y F O R T H E R M A L C O M F O R TTTTT


under a condition in which we humansconsume as low amount of exergy aspossible.

That is, we may be able to establishboth thermal comfort and low-exergyconsuming systems at the same time.

LOW EXERGY SYSTEMS AND HUMANLOW EXERGY SYSTEMS AND HUMANLOW EXERGY SYSTEMS AND HUMANLOW EXERGY SYSTEMS AND HUMANLOW EXERGY SYSTEMS AND HUMANBODY EXERGY CONSUMPTIONBODY EXERGY CONSUMPTIONBODY EXERGY CONSUMPTIONBODY EXERGY CONSUMPTIONBODY EXERGY CONSUMPTION

As explained in the previous section, thelowest human body exergy consumptionoccurs at thermally neutral condition.

Further research on human body exergybalance has just come onto a new stagewhere it becomes possible to calculatemore realistic cases than before, in whichthe environmental temperature for exergycalculation need not be presumed to beequal to the average indoor air temperatureand mean radiant temperature. What

follows is a new finding which enhances theprevious findings.

Figure 11 shows a new relationshipbetween the human body exergyconsumption, thermal comfort (PMV*=0),room air temperature and mean radianttemperature.

The lowest exergy consumption rateemerges at the point where the room airtemperature equals 18 °C and meanradiant temperature 25 °C. This suggeststhat the use of radiant warm exergy is moreeffective than the use of convective warmexergy for a heating purpose to realise boththermal comfort and as low exergy con-sumption within the human body aspossible. Such a built environment can beprovided by a moderate radiant heatingsystem combined with passive heatingstrategies, for example, good thermal

Figure 10. The relationship between the rates of exergy input, exergy consumed, exergy stored within thehuman body and also exergy output from the human body and the environmental temperature. Thedotted lines represent a case of no shivering in cold condition or no sweating in hot conditions (Saito et al.2002).

18 LOWEX GUIDEBOOK

Figure 11. The relationship between exergy consumption within the human body (W/m2), room airtemperature, and mean radiant temperature. The solid line descending from the upper left corner to thelower right corner indicates thermally neutral conditions (PMV*=0); this is based on ‘energy’ balancecalculation. The broken line in the upper right corner is skin wetness up to the amount which mostpeople find tolerable (W=0.25). There is an optimal combination of room air and mean radianttemperatures which results in the lowest exergy consumption and thermal comfort (Isawa et al. 2002).

insulation and suitable thermal exergystorage capacity of building envelopes,solar thermal exergy gain through properlyinsulated window glazing and others.

It is interesting to see that, from theexergetic point of view, there is an optimalcombination of room air temperature andmean radiant temperature which results inthermally neutral conditions, namelyPMV*=0, although, from the conventionalenergetic point of view, there are manycombinations of room air temperature andmean radiant temperature. Some experi-enced scientists and engineers say thatwhat they can see in Figure 11 is consistentwith their experiences. It would be veryencouraging for architects and engineers toconceive a system with as low-exergy

consumption as possible since it wouldbring about a higher quality of warmnessthat the occupants can sense in their givenbuilt environment.

19ANALYSIS TOOLS FOR THE EXERGY CHAIN

3. ANALYSIS TOOLS FOR THE EXERGY CHAIN

In the preparation phase of Annex 37,the working group set as an objective tocollect the tools available on the marketand to review them from the viewpoint ofadaptability for exergy analyses. Quitequickly the group realised, that there wereno representative off-the-shelf tools forexergy analysis of buildings. Because itwas not possible to develop a very ad-vanced tool in the frame of the Annex 37,the participants finally decided to developguidelines for tool developers, instead ofchoosing one tool to be developed forexergy analysis. The guidelines includemodels for exergy analysis of differentsystems. They are presented in thepublication “Introduction to the Concept ofExergy” by Shukuya and Hammache(2002).

The participants also recognised theimportance of developing a simplified toolto visualise why low exergy systems would

be advantageous in some energy chainscompared to high exergy systems. This toolshould be easy to use and show the exergyflow through a system or energy chain.Finally, two pre-design tools weredeveloped (named as “the Pre-design tool”and “the Educational tool”). They are brieflydescribed in this chapter, and moredetailed descriptions can be found in theUser-Guides of these tools (François et al.2004a and b). Both the User-Guides andthe tools are included in the CD-version ofthe Guidebook.

Both tools give outputs of similar format.The main difference is that the Pre-designtool is even more easy-to-use than theEducational tool, but it is therefore also lessflexible. The ease-of-use is based on thedrop-down lists, which are used morefrequently in the Pre-design tool. In theEducational tool, the user has more optionsfor the input parameters, but here the user

To increase the understanding of

exergy flows in buildings and to be

able to find possibilities for further

improvements in energy utilisation

in buildings, two pre-design

analysis tools have been produced

during ongoing work for the IEA

ECBCS Annex 37.

Figure 12. Energy (or exergy) flows overthe systems boundaries of a building(Schmidt 2004).

Figure 13. Energy utilisation in buildingservices equipment (according DIN4701-10 2001, modified).

20 LOWEX GUIDEBOOK

has to know more facts about the buildingand its systems. The Educational tool doesan analysis of a single moment, as the Pre-design tool gives an estimate of the annualenergy and exergy demand of the building.

The exergy chain is described in chapter2.1.1 of the Guidebook. An important stepin the entire analysis is the estimation ofthe energy demand of the actual building.The heat demand is a key figure in theanalysis, it corresponds to the building’sexergy load. A low exergy load means athermally good constructed buildingenvelope. The energy requirement for theservice equipment is then estimated.(Schmidt 2004)

The main focus in the Guidebook is onthe system “building”, whose systemborder to be analysed here encompass thebuilding envelope. All energy (or exergy)flows over the border are indicated inFigure 12. For the balance of energy flows

through the building, all possible effectshave to be taken into account, even theextraction and production of the energycarrier. The calculation of energy flowscaused by a building starts much earlier.(Schmidt 2004)

For a deeper analysis of the energy flowsin a building, a closer focus on the buildingservices system is needed. The entire flowfrom the source to the sink, as indicated inFigure 13, must be taken intoconsideration. All energy flows from the lefthand side, i.e. from the source, via anumber of HVAC-components and thebuilding structure itself, to the ultimate sink,the outdoor environment. Imperfections andlosses in the different steps through thebuilding are regarded, as well as the needfor auxiliary energy. Energy, mainly in formof electricity, is needed to drive additionalpumps and fans for the operation of thesystem. (Schmidt 2004)

DESCRIPTION OF THE TOOLThe detailed presentation of the tool can

be found in the document called “User-Guide for the Educational Tool for Energyand Exergy analyses of Heating andCooling Applications in Buildings” (Françoiset al. 2004a).

All steps of the energy chain - from theprimary energy source, via the building, tothe sink (i.e. the ambient environment) - areincluded in the analysis (Figure 14). Theentire tool is built up in different blocks ofsub-systems for all important steps in theenergy chain. All components, buildingconstruction parts, and building servicesequipment, have sophisticated inputpossibilities. Heat losses in the differentcomponents are regarded, as well as theauxiliary electricity required for pumps andfans. The electricity demand for artificiallighting and for driving fans in theventilation system is also included. On theprimary energy side, the inputs aredifferentiated between fossil and renewablesources. The steady state calculation forthis heating case is done in the direction ofthe development of demand.

Although the analysis follows the samemain principles as European Standards do,the tool is aimed at calculations understeady state design condition, not at annualenergy use calculations (the user can entermean values of climatic data to representseasonal or annual average conditions).

The tool mainly presents seven parts ofan excel worksheet. The worksheet isdivided into seven different sections for theinput and calculation of values.

The user can run this tool for example tostudy:

- the impact of improvements in thebuilding envelope versus improvements inthe service equipment,

- the system flexibility and the possibleintegration of renewable energy sourcesinto building systems,

- integration of heat pumps into thebuilding design,

- integration of balanced ventilationsystems.

Throughout the development of the

”Educational Tool for Energy and

Exergy Analyses of Heating and

Cooling Applications in Buildings”,

the aim was to produce a “transpar-

ent” tool, easy to understand for the

target group of architects and

building designers, as a whole.

Other requirements were that the

exergy analysis approach is to be

made clear and the required inputs

need to be limited. Today, the

Microsoft Excel spreadsheet based

tool has two input pages and results

are summarised on two additional

pages, with diagrams.

EDUCATIONAL EXERGY ANALYSIS TOOL FOR HEATING


Figure 14. Energy utilisation in building servicesequipment, the modelling method for the pre-design tool. The energy flows are shown formsource to sink, in accordance to DIN 4701-10,modified.

FORM OF RESULTSThe results are displayed as diagrams

showing demands and losses bycomponents (Figure 15). In these diagrams,it is easier to understand where inefficien-cies occur and possible steps for a furtherincrease in the system efficiency may beindicated.

Figure 15. The results of the tools are presentedgraphically.

22 LOWEX GUIDEBOOK

DESCRIPTION OF THE TOOLThe heating and cooling requirements are

estimated using descriptive data where theuser should enter the physical characteris-tics of the building and the characteristicsof the site. Simplified energy and exergyanalyses are carried out on the systemcomponents of selected heating andcooling technologies. The exergy analysis iscarried out using estimated quality factorsof the energy flow in the system.

It is important to emphasise that the toolis not intended to carry out sophisticatedenergy and exergy analyses that requiremore detailed information on the technolo-gies, the subsystem configurations, theoperating parameters and the energyvectors used, so that all the exergy compo-nents could be taken into account andcalculated precisely. This will require moresophisticated software, which is beyondthe objective set to the tool.

and explained. Typical values are providedfor each parameter and since the method-ology uses qualitative estimates on someparameters, the assumed values are alsoindicated in different tables.

For example, the heating and coolingapplications are selected from drop-downlists. There are twenty-three optionsavailable for the heating generation andtwelve options for the cooling technology.

FORM OF RESULTSThe results are presented on three

worksheets, 4. to 6.

Heating and cooling load worksheetThe “Heating and Cooling Load” work-

sheet is a report that summarises all thecharacteristics of the site conditions andthe parameters entered by the user. Theoutput for the building design heating andcooling loads as well as the building heatingand cooling energy demands are alsoshown. In addition, the model calculatesthe corresponding exergy quantity for eachvariable by using a quality factor dependingon outside and inside air conditions. Thequality factor for the design exergy load iscalculated using a constant design temper-ature. The quality factor for the exergydemand is calculated using variabletemperature bins.

Heating worksheetThe “Heating” worksheet is a report that

summarises the heating applicationassessment from both the energy andexergy situations. All the components of theheating process are indicated, as selectedby the user, with their characteristics andestimated parameters. The worksheetproduces the energy and exergy analysesas flow patterns along the different subsys-tems. These analyses are presented in twoformats, as tables and curves in theprovided figure. The extent of the exergylosses in each subsystem can be deducedfrom the figure (see Figure 16).

PRE-DESIGN TOOL FOR HEATING AND COOLINGThe objective of the ”Pre-Design

Tool for Energy and Exergy

Analyses of Heating and Cooling

Applications in Buildings” is to

provide designers or users with a

simple tool that shows a holistic

image of the energetic-flow and

exergetic-flow patterns of various

low temperature heating and high

temperature cooling systems in

buildings. For this purpose, the tool

includes a program that estimates

the heating and cooling

requirements of a building using

the well-known modified-bin

method (ASHRAE 1997).

More information on the contents ofthese worksheets and on the use of thetool can found in the User-Guide of the tool(François et al. 2004b). It is included in theCD-ROM version of the Guidebook. Here,only some characteristics are given.

In order to provide a simple and easy-to-use tool, the inputs are mainly entered fromdrop-down lists on the Input Parametersworksheet. All the required input parame-ters for the computations are introduced

THE TOOL MAINLY PRESENTSSIX EXCEL WORKSHEETS:

1. Overview worksheet

2. Procedure worksheet

3. Input Parameters worksheet

4. Heating and Cooling Load worksheet

5. Heating worksheet

6. Cooling worksheet


Figure 16. Example of the output of thePre-Design Tool. This is a part of the”Cooling” worksheet. In addition tothese curves, the results are presentedin table format. (Hammache andShukuya 2004)

Cooling worksheetSimilarly to the “Heating” worksheet, the

“Cooling” worksheet is a report thatsummarises the cooling applicationassessment from both the energy andexergy situations. All the components ofthe cooling process are indicated, asselected by the user, with their characteris-tics and estimated parameters. The

worksheet produces the energy and exergyanalyses as flow patterns along the differentsubsystems. These analyses are presentedin two formats, as tables and curves in theprovided figure. The extent of the exergylosses in each subsystem can be deducedfrom the figure (see Figure 16).

24 LOWEX GUIDEBOOK

4. CONCEPTS AND TECHNOLOGIES

For future buildings, a minimum of energyat a very low level of temperature differencebetween the system and the room shouldbe used for thermal conditioning. In thisway a maximum of high quality energy(exergy) could be saved.

The big efforts made in the field ofenergy saving in buildings by constructingwell-insulated and tight envelopes, suffi-cient window shading and the use of

The LowEx database in chapter 4

of the Guidebook consists of sixty-

two information sheets, which

describe the technologies; their

basic principles, technical risks

and benefits, advantages, limita-

tions and state-of-art (commercial-

ly available, prototype or innovative

concept). The idea is to give a

quick overview of the possibilities

and limitations of the technologies.

Some system concepts, which are

compiled with these components

are presented in section 4.3 of the

Guidebook.

thermal storage result to a much betterusage of the energy. But there is still a bigsaving potential left. To make the energyuse in buildings even more efficient, newlow temperature heating and coolingsystems are required. The components andsystems presented in chapter 4 of theGuidebook show a step further in thisdirection.

SUMMARY TABLE OF THE LOWEX TECHNOLOGIES

On the following pages, a summary tableof the LowEx technologies is presented,with some key information of thecomponents.

At the CD-ROM there is a link to thecase, where the technology has been

used. There is also a search function, withwhich the technologies can be sorted bydifferent parameters. There are links fromthe summary table to the data sheets.

Boiler /

Cooler

S.1.1

T.1.1

A.1.1

G.2.1 D.1.1Figure 17. Examples of LowEx technolo-gies.

25CONCEPTS AND TECHNOLOGIES

Table 1. Summary table of the LowEx technologies.

X X X

X X X X X

X X X X

X X X X

X X X X X

X X X X X

X X X X

X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X

X X X X X

X X X X

X X X X X

X X X X X

X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X

X X X X

X X X X X

X X X X X

X X X X X

X X X X

X X X X X

S SURFACE HEATING AND COOLING

S.1 Floor heating

S.1.1 Embedded coils in slabs

S.1.2 Coils in surface layers

S.1.3 Hollow core slabs

S.1.4 Suspended floors

S.1.5 Phase change in floor heating

S.2 Wall heating and cooling

S.2.1 Pipes in surface layers (wet/half wet, mounted)

S.2.2 Pipes in surface layers (half-dry embedded)

S.2.3 Pipes in surface layers (wet, embedded)

S.2.4 Pipes in surface layers (dry systems)

S.2.5 Double walls

S.2.6 Dynamic insulation

S.2.7 Capillary tubes

S.3 Ceiling cooling and heating

S.3.1 Radiative panel

S.3.2 Cooling beams

S.3.3 Ceiling integrated system

S.3.4 Evaporative roof surfaces

S.3.5 Ceiling panel cooling by double-roofing with

water spray

S.4 Local heaters

S.4.1 Low temperature radiators/convectors

S.4.2 Radiators integrated in the interior design

S.4.3 High temperature radiators

S.4.4 Base board heaters

S.4.5 Transparent insulation

A AIR HEATING AND COOLING

A.1 Air to air heat exchangers

A.1.1 Sensible only heat exchangers /

Recuperator

A.1.2 Counter flow air to air heat exchangers/

Recuperator

A.1.3 Total (latent) heat exchangers / Regenerator

A.1.4 Altering heat exchangers

A.2 Water to air heat exchangers

A.2.1 Supply air conditioning

A.2.2 Fan coil units

A.3 Steam / vapour to air heat exchangers

A.3.1 Supply air conditioning

A.4 Other heat exchangers

A.4.1 Supply air façade

A.4.2 Evaporative cooling

10-15

16-20

15-18

16-20

-

10-15

10-15

10-15

10-15

10-15

10-15

10-15

10-15

10-15

15-20

-

10-20

-

-

10-15

10-19

10-15

-

Wet bulb temperature

25-30

28-35

25-30

30-40

25-50

25-50

25-50

25-50

25-50

25-50

25-50

25-50

25-50

25-50

25-50

-

-

30-50

20-40

80-130

40-95

40-95

20-50

25-50

40-95

40-90

25-30

100-120

20-100

-

Res

iden

tial

Res

iden

tial

Res

iden

tial

Res

iden

tial

Res

iden

tial

No

n-r

No

n-r

No

n-r

No

n-r

No

n-r e

sid

entia

les

iden

tial

esid

entia

les

iden

tial

esid

entia

l

New

New

New

New

New

Ret

rR

etr

Ret

rR

etr

Ret

r ofit

ofitofit

ofit ofit

Co

ncep

tC

onc

ept

Co

ncep

tC

onc

ept

Co

ncep

t

Exp

erim

enta

lE

xper

imen

tal

Exp

erim

enta

lE

xper

imen

tal

Exp

erim

enta

l

Co

mm

eric

alC

om

mer

ical

Co

mm

eric

alC

om

mer

ical

Co

mm

eric

al

WHAWHAWHAWHAWHAT ?T ?T ?T ?T ?No.No.No.No.No. Suitable forSuitable forSuitable forSuitable forSuitable for State ofState ofState ofState ofState ofthe artthe artthe artthe artthe art

CostsCostsCostsCostsCosts

Cooling temp. [°C]Cooling temp. [°C]Cooling temp. [°C]Cooling temp. [°C]Cooling temp. [°C]00000 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0

Heating temp. [°C]Heating temp. [°C]Heating temp. [°C]Heating temp. [°C]Heating temp. [°C]00000 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0highhighhighhighhigh

mediummediummediummediummedium

lowlowlowlowlow

26 LOWEX GUIDEBOOK

X X X

X X X

X X X X X

X X X X

X X X X

X X X X X

X X X

X X X X X

X X X X

X X X X X

X X X X X

X X X X

X X X X X

X X X

X X X

X X X X X X

X X X X

X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X X

A.5 Passive systems

A.5.1 Atria

A.5.2 Solar chimneys

G GENERATION / CONVERSION OF COLD AND HEAT

G.1 Boiler

G.1.1 Condensing boilers

G.1.2 Pulsating gas boiler

G.2 Ground heat

G.2.1 Ground coils

G.2.2 Bore hole

G.2.3 Slab on ground

G.3 Heat pumps

G.3.1 Compressor heat pumps

G.3.2 Absorption heat pumps

G.4 Solar collectors

G.4.1 Flat plate collectors

G.4.2 Evacuated tube collectors

G.4.3 Unglazed flat-plate collectors

G.5 Combined heat and power generation

G.5.1 Cogeneration units with gas motor

G.5.2 Cogeneration units with microturbines

G.5.3 Cogeneration units with stirling motor

G.6 Fuel cells

G.6.1 Fuel cells

G.7 Biological systems / Metabolic

G.7.1 Bacteria

G.7.2 Animals

G.7.3 Plants

T THERMAL STORAGE

T.1 Seasonal storage

T.1.1 Ground / rock storage

T.1.2 Earth duct storage

T.1.3 Hot water storage

T.1.4 Phase change thermal storage

T.2 Short term storage

T.2.1 Buffer storage tank

T.2.2 Domestic hot water tank

D DISTRIBUTION

D.1 Transfer medium

D.1.1 Air

D.1.2 Water

D.1.3 Thermera® heat carrier

D.1.4 Glycol

D.2 Community systems

D.2.1 District heating

D.2.2 District cooling

50-80

-

18-22

-

25-50

-

20-80

20-120

20-80

80-90

20-60

20-35

-

40-100

45-75

35-95

40-90

45-60

65-115

-

Res

iden

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Res

iden

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Res

iden

tial

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iden

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Res

iden

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n-r

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n-r

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sid

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les

iden

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esid

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les

iden

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esid

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l

New

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erim

enta

lE

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erim

enta

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enta

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WHAWHAWHAWHAWHAT ?T ?T ?T ?T ?No.No.No.No.No. Suitable forSuitable forSuitable forSuitable forSuitable for State ofState ofState ofState ofState ofthe artthe artthe artthe artthe art

CostsCostsCostsCostsCosts

Cooling temp. [°C]Cooling temp. [°C]Cooling temp. [°C]Cooling temp. [°C]Cooling temp. [°C]00000 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0

Heating temp. [°C]Heating temp. [°C]Heating temp. [°C]Heating temp. [°C]Heating temp. [°C]00000 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0highhighhighhighhigh

mediummediummediummediummedium

lowlowlowlowlow

-

-

8-18

8-18

16-22

10-15

10-15

-

-

-

-

-

-

-

-

-

20-25

8-20

10-15

-

5-15

-

6-10

2 7CONCEPTS AND TECHNOLOGIES

LOWEX SYSTEM CONCEPTS

One example of a LowEx system is theuse of boreholes to provide cooling insummer. This was apparently a very promis-ing method but in some cases the boreholewould gradually over the years becomewarmer and above the temperatures thatcould be used for direct cooling in a rationalway. By also extracting heat in winter with aheat pump, the heat balance of the hole isrestored and the system solution becomessustainable in time. In most cases whereexergy is being consumed at differenttemperature levels in the same system athorough system study in an exergyperspective can lead to substantial savings.

THERMONET SYSTEM CONCEPT FORHEATING AND COOLING

ThermoNet system can be applied to avariety of building types including hospitals,swimming halls, offices, industrial buildings,

In recent years system solutions

have appeared where heating and

cooling is carried out in a holistic

system solution where the energy

use is planned in a wider and more

general perspective.

residental high-rise buildings etc. An applica-tion of ThermoNet system for grocerystores (Figure 17) is presented in chapter4.3.1 of the Guidebook.

The exploitation of condensation heat,waste heat, and excess energy in a Ther-moNet system is based on two factors: anair heating system that utilises low tempera-ture technology, and efficient energy recov-ery. By applying ThermoNet technology, theconsumption of purchased energy may becut by more than one half when compared toconventional solutions, and electricalconsumption may be reduced to one third.The ThermoNet low temperature system isable to utilise district heating return waterfrom other properties, reducing peak loadsby 60-70 %.

Figure 18. A LowEx system for a grocery store.

2 8 LOWEX GUIDEBOOK

Figure 19. Main components of theARE Sensus system.

+-

+-

+-

Air handling unit

Cooler

Heat distributioncentre

Bui

ldin

g au

tom

atio

n

Internet

HEATING AND COOLING WITH ARESENSUS

The use of Sensus® building servicessystem (Figure 18) in an office building isdescribed in chapter 4.3.2 of the Guide-book. The exergy consumption of theSensus® system is lower than in comparablehigh-standard systems, which also decreas-es environmental impact during use.

Office ventilation employs a Sensus®

ventilation unit connected to the Sensuspanels with a three-pipe network. Theventilation units utilise surplus heat collectedfrom the rooms with the cooling watersystem for the heating of intake air wheneverheating is needed for the intake air. Thisconserves heating exergy. The ventilationmachine also has an efficient rotating heatcollector for the exhaust air (over 70 % heatefficiency).

The Sensus® ventilation unit utilisesoutdoor air for cooling the cooling water forthe rooms when outdoor temperature issufficiently low (under +12–14 °C). This freecooling carried out with ventilation unitsoperates alongside mechanical cooling whennecessary. It has a considerably longerannual period of utilisation (over half of theyear’s working hours) than conventional freecooling. This lowers the electricity consump-tion of cooling unit in the Sensus® system incomparison with conventional solutions.

CEILING COOLING WITH WELL WATERAn other system concept described in

chapter 4 of the Guidebook is a ceilingradiant cooling system using well water, andwith outdoor sun shading on the South-facing window. The ceiling radiant coolingsystem is installed in the living room (Figure

Figure 20. The house equipped withceiling radiant cooling system usingwell water (Asada and Takeda 2002).

2 9CONCEPTS AND TECHNOLOGIES

20, right hand side) of a two-storey woodenhouse, which has well-insulated exterior wallsand double-glazing windows. The livingroom window (3.6 m x 2.2 m) faces south.

Figure 21 schematically shows majorcomponents and well water flow in the ceilingradiant cooling system: deep well (depth: 66m), well water pump, three-way valve,circulation pump, ceiling radiant panel(aluminum panel with embedded pipes), andpercolation well. Water from the deep well ispumped up and mixed with return waterfrom the ceiling radiant panel by the three-way valve to maintain the temperature at theset point. The circulation pump enables thismixed water to run within the panel and coolit. A portion of the return water is sent to thethree-way valve and the rest is discarded viathe percolation well.

Figure 22. Exergy analysis of a floorheating system using a heat pump asenergy generator.

0

500

1000

1500

2000

2500

3000

3500

4000

1 6 7 8

En

erg

y/E

xe

rgy

(W)

energy total

heat energy

aux energy

incl. free /rene. ener.

exergy

Generation Emission Room Air EnvelopeDistributionStoragePrim.

Energy

transform

2 3 4 5

INNOVATIVE HEATING CONCEPTThe energy source for this system

concept is ground heat. This heat is extract-ed through a heat pump. The emissionsystem is, instead of a conventional floorheating system, a floor heating with phasechange (chapter 4 in the Guidebook, datasheet S.1.5). This floor heating system has aphase change material (PCM) that can beutilised to store the energy from a solarcollector during the day. During the night theenergy is released and warms up the room.The same floor heating system could also beused the other way around, “charging itself”during the night and releasing the heat duringthe day. This could be of use when using aheat pump.

The heat pump uses electricity, about onethird of its supplied energy amount. Lookingat the electricity distribution system, there isan “overload” in the network during the night.The system is designed to cover the peaksthat occur during the day. The best thing forthe energy production point of view wouldbe to have an even consumption curve. Byusing electricity during night time we contrib-ute to making this curve more even, and weget economically compensated for this withthe right kind of electricity contract.

The exergy analysis of such a systemlooks just like the analysis of a system with atraditional floor heating system (Figure 22).

Figure 21. Components and well waterflow (Asada and Takeda 2002).

3 0 LOWEX GUIDEBOOK

STRATEGIES FOR DESIGN OF LOW EXERGY

SYSTEMS IN BUILDINGSThe aim of the design process

presented here is to make energy

efficient buildings that can provide

the occupants with comfortable,

clean and healthy environment. The

building should always be designed

as a whole, i.e. the different parts

should work together optimally and

not obstruct each others operation.

The design process is or at least shouldbe an iterative process. There will always bea need to go back to earlier step and revisethe choices made. The design process isdescribed in Figure 23. The terms in theboxes are more explained in chapter 4.4 ofthe Guidebook.

Figure 24. Acoustics played animportant role in design of the SibeliusHall in Lahti, Finland (see Case FIN 2 inthe Guidebook).

Figure 23. The design process of a building as asystem.

31 EXAMPLES OF LOWEX BUILDINGS

5. EXAMPLES OF LOWEX BUILDINGS

The case examples show the wide vari-ety of applications of low exergy (LowEx)systems. They also demonstrate the flexi-bility of the systems with regard to theenergy source. There are examples ofLowEx systems in dwellings and offices, butalso in a museum, a church and a concerthall. In these examples there are systemsthat use heating or cooling energy from thesun, the ground, a district heating networkas well as an electricity or gas network.

Findings from the literature (chapter 5.4.1in the Guidebook) show that the applicationof LowEx systems provides many additionalbenefits besides energy supply, such asimproved thermal comfort, improved indoorair quality and reduced energy consump-tion.

In chapter 5 of the Guidebook,

examples of the use of LowEx

systems in various buildings are

presented. Together with the

findings from a literature study and

an occupant survey, which are also

presented in this chapter, the case

examples give strong evidence that

in addition to the desired heating or

cooling effect, LowEx systems can

provide occupants with a comforta-

ble, clean and healthy environment.

Demonstration projects have beensubmitted by all participants: 27 examplesplus 3 extra cases from the LowExx (LowExsystems in existing and historical buildings)group. With 30 cases, distributed over newand existing buildings, residential and non-residential buildings with various technolo-gies and emission systems, this gives agood overview of the application of LowExsystems for heating and cooling of build-ings. Table 2 and Table 3 show the distribu-tion of the cases. Most cases are new non-residential buildings. Floor heating is themost commonly used emission system inthe case buildings. Most of the cases arelow temperature heating cases; in only 12cases high temperature cooling is applied.From the table on the following page youcan get an overview of the cases. In chapter5.2 of the Guidebook the cases are present-ed in more detail on 2 to 4 pages each.

The first page of each fact sheet gives anoverview on the project by a generaldescription accompanied with a picture ordrawing of the building. The heating andcooling system of the building is characteri-sed with a list of keywords that are pickedup from a selection. Some general dataabout the project team and the building isgiven. The installations are described withmore detail in the following pages by words

Table 3. Distribution of emission systems.

Table 2. Distribution of building types.

The Dutch occupant survey (chapter 5.4.2in the Guidebook) shows that all lowtemperature systems are well received. Inparticular, the occupants found the indoorclimate to be significantly better in dwell-ings with floor and wall heating compared totheir previous dwellings. The main disadvan-tage was controllability. The advantages anddisadvantages, mentioned by the occupantsin the survey, are similar to results in theliterature.

The experiences from the case examplesalso agree with the findings from theliterature: In addition to the desired heatingor cooling effect, LowEx systems canprovide occupants with a comfortable, cleanand healthy environment.

SUMMARY TABLE OF CASE STUDIES

and schemes. Measurement results arepresented where appropriate.

In the Guidebook, cases are presented bycountry in alphabetical order. On the firstpage of each fact sheet, there is a mapshowing the locations of different casebuildings in that country.

32 LOWEX GUIDEBOOK

Table 4. Summary table of case studies.


The existing building stock is veryimportant to focus on, the renewal of thebuilding stock is very slow, and if weneglect the possibilities for LowEx systemsin the existing buildings, the total effect willnot be as large as we hope for.

There are special issues to take in toconsideration when we are talking aboutapplying LowEx systems in existingbuildings, these will be reviewed here.Some examples of LowEx systems inexisting buildings are presented in the caseexamples of the Guidebook (11 retrofitcases), one example is a historical buildingwith a cultural heritage, which means aneven greater challenge.

The age of the building is not such animportant issue when considering thepossibilities for applying LowEx systems.The important aspects are the degree ofprotection of the building, the building type,the scale of renovation, replacement ofinstallation and the type of LowEx systemto be applied.

A good timing is very important whentrying to market LowEx systems intoretrofits. When a renovation is doneanyway, it is much easier and cheaper to

install a new heating/cooling system than ifyou start a whole renovation just to changethe system. In residential houses, it is verycommon that when the house ownerchanges, some renovation is done. There-fore, some marketing of LowEx systemsshould be made at the time of the pur-chase of the house.

Even though the low temperature heatingsystems are functional systems with lots ofadvantages, we need to keep in mind thatwhen we are talking about retrofits, thereare also some technical limitations. In oldhouses the walls are not always that good,and one can encounter really poor U-values. If this is the case, floor heating isnot efficient enough to meet the heatingdemand. The exergy analysis tools devel-oped in the Annex 37 group can help withthis problem (Chapter 3). They calculate ifthe system is efficient enough to heat thehouse. Another problem could be that wecan not make the floor any higher than it is.For this problem, there are solutions withvery thin constructions, only a bit more than2 cm for the whole construction (chapter 4in the Guidebook, data sheet S.1.2).

Reasons for applying LowExx:- Esthetical- Improved indoor climate/comfort- Conservation of cultural heritage- Lower energy use- Use of renewable energy- Energy efficiency- Integration of heating and cooling sytems.

Opportunities for applying LowExx:- Large scale renovation: combination with

other measures:· acoustic matters· upgrading the building or a part of

the building more luxury- Cooling can be added- Improving indoor climate- Adjusting office to modern IAQ standards:

increased productivity of employees- Moisture problems-protection of art work,

preventive conservation- Extended use of the building- Flexibility

· CO2 potential· uncertainty of energy prices

- Awareness is raising- Energy Performance Standard (EPS)

based on primary energy

Limitations/Threats for applying LowExx:- Low price of fossil fuels, low electricity

prices- Availability on the market/market price- No checking of regulations- Comfort criteria isn’t that high in existing

houses as in new ones- Stick to tradition- Lack of knowledge

RETROFITS

OPPORTUNITIES AND THREATS

34 LOWEX GUIDEBOOK

OCCUPANTS’ EXPERIENCES ON LOWTEMPERATURE HEATING SYSTEMS

One of the critical success factors for theimplementation of Low Temperature (LT)heating systems in residential buildings isthe way these systems are viewed andaccepted by the occupants. At the mo-ment costs for such systems for dwellingsare higher than those for traditional HighTemperature (HT) systems while energysavings in some cases are only marginal.This means that LT systems must havesome additional qualitative benefits foroccupants (thermal comfort, indoor airquality, safety, etc.). The overall perform-ance of LT heating systems must be atleast equal or preferably better than that oftraditional HT systems.

An occupant survey was conducted inthe Netherlands in October 1999 among409 households with LT heating systems. Itis described in chapter 5.4.2 of theGuidebook. The first objective was to makean inventory of the experiences ofoccupants with LT systems, and to see ifthese systems fulfil their expectations.These results can also convey informationabout possible obstacles in further marketintroduction.

Results of this survey can not be general-ised for the total Dutch new building stock.All studied projects were demonstrationprojects for LT systems.

Occupants were asked about theiropinion of the indoor climate in terms ofwhether or not it had improved in relation tothe indoor climate in their previousdwelling. Notable was the very positivescore for floor and wall heating (>70 %). Upto 61 % of the occupants with LT radiatorsdid not notice any difference. The resultsfor wall heating do not differ from previousoccupant surveys (demonstration projectsfor sustainable building – Silvester et al.2000).

Occupants did not initially choosedwellings based on environmental factors.However, for 58 % the environmentalaspect was important in the final selectionof their dwelling. Floor heating is an

IMPACT ON IAQ, THERMAL COMFORTAND ENERGY CONSUMPTION

The literature study presented in chapter5.4.1 of the Guidebook was conducted byEijdems et al. (2000), as a part of a Dutchprogram for the implementation of LowTemperature Heating (LTH) systems inbuildings, which was initiated by theNetherlands Agency for Energy and theEnvironment (NOVEM). The primary goal ofthe program was to enable the use of LowValued Energy as a heating source. Majorsavings in energy consumption can berealised by fully utilising the potential of LowValued Energy.

The study by Eijdems and Boerstra(1999) shows that lowering the tempera-tures for heat distribution systems, besidesthe possibilities of savings in energy supply,gives additional benefits such as:- Thermal Comfort increases in many

respects (greater share of radiant heattransfer, less temperature gradients,better floor contact temperature, lessdraught and air turbulence);

- The IAQ is also positively influenced (lessdust singe and house dust mites, lessstuffiness and odours through lower airtemperature, less suspended particles);

- In addition to the ability to use LowValued Energy, savings are gained frombetter performances of boilers and heatpumps, less piping heat loss and lessventilation losses.Other benefits might occur, like avoid-

ance of burning risk, extra space due tothe absence of radiators, avoidance ofmould growth, etc. Many disadvantagescan be avoided by means of a properdesign and compensating measures.Arguments against LTH systems oftenappear to be based on negative experienc-es in the past (bad design or insulation) or alack of knowledge.

By highlighting these additional benefits,an easier introduction of LTH systemsmight occur. Application on a broader scalewill also lower the prices of these systems.

ADVANTAGES AND LIMITATIONS OF LOW EXERGY SYSTEMS


important factor in the decision-making butis not considered as a particular energy orenvironmental measure. Therefore, addi-tional information and communicationconcerning the energy efficiency of LTsystems is recommended.

A majority of the respondents with LTradiators did not have any idea that theyhave an LT system. On one hand this ispositive because this suggests that thereseems to be no difference (disadvantage) incomparison with more conventionalsystems. However, further communicationabout the energy efficiency of thesesystems could still be recommended.

There was a significant differencebetween the set points of the thermostatsbetween the different LT systems duringwinter nights (Table 5). Occupants with floorand wall heating applied a small

temperature difference to compensate fornight set back.

Occupants would also be interested inlearning how to use their heating applian-ces to reach an optimal balance betweenenergy use and thermal comfort. About50 % of the occupants did not use heatingin bedrooms during wintertime.

The advantages and disadvantages,mentioned by the occupants in this survey(Table 6) back up results from previousresearch. This survey also confirms theresults of the literature review on sideeffects of low exergy emission systems(chapter 5.4.1 of the Guidebook).Especially the occupants´ perception ofindoor air quality, thermal comfort, slow-ness and controllability of some LT-systemsconfirm results from previous studies.

Although LT-systems are very wellaccepted and appreciated (Figure 25),there are some negative aspects anddisadvantages that should be taken intoaccount and solved. These are for examplesystem controllability per room (floor andwall heating) and the size, design andinstallation of LT radiators.

All systems were very well received bythe occupants. Particularly indoor climatehas improved a lot in dwellings with floorand wall heating in relation to their previoussituations (Figure 26). For LT radiators theoccupants found no difference in the indoorclimate compared to their previousdwellings. The main disadvantage is thepoor controllability, especially with floor andwall heating; 30 to 40 % of the occupantsmention poor controllability as adisadvantage.

Figure 25. Do you think that LT systemgives pleasant or unpleasant heat?

Figure 26. Do you think that LT systemgives an improvement of the indoorclimate or not?

80

6070

5040

302010

0% floor wall radiator

pleasant

quite pleasantunpleasant

80

6070

5040

302010

0% floor wall radiator

improved

equalworsened

Table 5. Set point temperatures.

T-average(oC) winter

evening

T-average(oC) winter

night

Floor heating 19.9 17.8

Wall heating 20.3 17.6

LT-radiators 20.6 15.1

36 LOWEX GUIDEBOOK

EXPERIENCES FROM CASE STUDIESUser experiences

Several case studies include feedbackfrom occupants about their experienceswith LowEx heating or cooling systems intheir buildings.

This information is available for thefollowing cases:- Netherlands: Amboise, Weerselostraat,

Molengronden, Rijkswaterstaat- Canada: Downey Road- France: Hotel de Croy- Japan: IDIC Research Centre,

Sustainable Eco-house, YIES, Kumamoto- Sweden: Villa Akander, Villa Wahlin- Germany: ZUB Centre for sustainable

BuildingIn general, the feedback from users has

been very positive. In all cases theoccupants were satisfied with the installedLowEx systems.

Residential buildingsIn the existing dwelling Villa Akander,

occupants felt that the thermal comforthad significantly increased after the instal-lation of the floor heating system. TheKawasaki Sustainable Eco House providesa high level of comfort for the occupants inthe heating as well as the cooling case(fresh and dry air). Children living in theneighbourhood like to visit this house be-cause of its comfort level. Also the Dutchcase studies show that the occupantswere satisfied with the LowEx systems.Occupants of the Amboise projectmentioned that the wall heating system

played an important part in their decision tobuy the house. The occupants also pre-ferred a lower set-point of the thermostatcompared to the one they were used toearlier (19 °C in stead of 21 °C). Thisconfirms the assumption that wall heating isequally comfortable at lower air tempera-tures than radiator heating.

Non-residential buildingsUsers of the ZUB-building indicated to be

satisfied with the indoor climate in thebuilding. In the cooling case of Hotel deCroy, occupants appreciated the reachedcomfort and they particularly praised theabsence of noise and air movement. IDICreported a highly satisfying indoor climateboth for human occupants as well as forindoor plants. Also Kumamoto occupantsstated that the building provides a healthywork environment under different seasonalclimates, particularly during the hot andhumid summer period. In the YIES buildingthe majority of the occupants claimed to besatisfied, although there were someremarks about the relatively slow heating-up time of the floor heating system.

Finally, a survey among the users of theRWS office in Terneuzen showedsignificantly higher occupant satisfactionwith indoor climate compared to standardoffices. There were no complaints at allregarding dry air, air dust, and air quality ingeneral; and significantly fewer complaintsconcerning eye irritation, temperaturefluctuations and overheating.

Table 6. The survey gives a good indication of the specific advantages and disadvantagesof each system.


MeasurementsMeasurements have been performed in

most of the case studies in order to gain abetter insight in system temperatures, airand radiant temperatures, heating up timeand air temperature distribution (thermalgradient). Also energy (exergy) consump-tion has been evaluated. More details canbe found in the paragraphs describing thecase studies in the Guidebook.

ConclusionsThe user experiences from the case

studies support the findings of the literaturereview on the “impact on IAQ, thermalcomfort and energy consumption” of

LowEx systems described in paragraph5.4.1 of the Guidebook. The measurementsperformed in the case studies also coincidewith the results of the literature review.

It can therefore be concluded that theexperiences from the case studies (meas-urements as well as user experiences)confirm the conclusions of the literaturereview.

Interestingly enough, LowEx systems arenot only preferable from an exergy point ofview, people also seem to appreciate the“softer” heat and coolness of the LowExsystems much more than the traditionalheating and cooling solutions.

38 LOWEX GUIDEBOOK

6. MARKET POSSIBILITIES

This chapter reviews the market

situation of LowEx systems in

different countries and presents a

summary from interviews that have

been conducted among the main

actors of the building field in

different countries. Only the

overview and summary are

presented in this Summary Report.

The country specific market

analyses can be found in the

Guidebook.

Table 7. Summary of the market situationin different countries.

OVERVIEW OF THE MARKETSITUATION

The application of LowEx systems is farmore common in new buildings than inexisting buildings. For example in TheNetherlands and in Norway it is more orless common practise to install low tempe-rature heating- or high temperature coolingsystems in new residential buildings. Forexisting residential buildings it is more of anunknown concept but the trend is, howev-er, positive. In Japan and Canada, hardlyany cases with LowEx systems installed inexisting residential buildings can be found.

The situation is somewhat similar for non-residential buildings. For these types ofbuildings, LowEx systems do not seem tobe as common in the new building stock asfor residential buildings. Table 7 summari-

ses the market situation in nine differentcountries. A higher number of crossesindicates a more common use of LowExsystems, and a positive trend is markedwith a star. Please note that information forthis table has been collected throughdiscussions with a small number of peoplefrom each country, and should therefore beconsidered indicative.

SUMMARY OF THE MARKETANALYSES

The market analyses in different countrieswere conducted as interviews with the mainactors in the building field. The targetgroups for the interviews were: principalcontractors, architects, consultants,manufacturers and suppliers, installers andend users.

In order to reach a wider application ofLowEx systems, arguments in favour of theuse of these systems need to becommunicated more clearly for all targetgroups in most countries. The positiveassociations need to be supported by goodexamples gained from the use of LowExsystems. When the additional benefits arereliably presented, people will mostprobably be willing to accept extra

Figure 27. Thermal comfort is important, butpeople sometimes tolerate incomplete comfort, likethis man sitting in an igloo on an ice sofa.

MARKET POSSIBILITIES 39

investment costs. Although thermal comfortis seen as an important factor, in somecountries end users are still ready to acceptincomplete comfort.

End users are usually not familiar withlow temeprature (LT) systems, except inGermany where these are quite wellknown. Manufacturers and suppliers,however, are usually familiar with LTsystems. Knowledge of LT systems variesconsiderably within the other interviewgroups in different countries and evenwithin the countries. One group that shouldraise particular concern is the architects

who are unfortunately not very familiar withLTS. This is the group that has greatinfluence in implementing the systems intothe market. In addition, although we knowthat LowEx systems offer some advantagesfor the architectural design, it seems thatthe architects are not aware of theseadvantages.

In general, LowEx systems seem tocreate very positive associations such asenergy efficiency, comfort, soft heating orsafety. There were a few comments aboutsuspected comfort problems, but thesewere exceptional. Some doubts about thefunctionality and ease-of-use of thesystems were expressed. Sometimes thesystems are regarded as new and unusualsystems, and are therefore seen assomething with which to be careful. Thereare groups that prefer sticking to traditionalsystems. In many cases LT hating wasassociated with floor heating, especially byarchitects but also by other groups andoften the systems were associated withrenewables. It seems that inadequateinformation about the systems is the majorcause for negative associations.

There is a lot of variation in attitudestowards extra investment costs. In Finland,France and Germany extra costs are lessaccepted than in Sweden, Netherlands orNorway. In Canada people are mostlywilling to pay for the extra benefits offeredby the LowEx systems. Extra costs aresometimes accepted also in Japan, whenthe additional benefits are clearlycommunicated. In other countries, too,good arguments are needed to change thenegative attitudes towards a willingness tomake extra investments. In some countriesLowEx systems are considered as luxurysystems.

In most countries, thermal comfort isseen as a very important factor in buildingdesign by all interview groups. Incompletecomfort is, however, tolerated by end usersin many countries. It seems that they donot know that they could demand betterthermal comfort in their houses. Also,architects often ignore thermal comfort as atarget. Controllability is often consideredmore important than thermal comfort.

Table 8.Summary table of the marketanalyses.

40 LOWEX GUIDEBOOK

The focus of the building codes has inmany countries been in reducingtransmission losses of building envelopes.This aim is still valid and it shall not beforgotten in the future. Requirements forreducing ventilation heat losses have beenset only in some countries so far. This aimshould be applied in building codes morewidely in different countries. Ventilation heatlosses are as important as transmissionlosses. They are even gaining moreimportance in future, when the transmissionlosses get smaller due to the better qualityof envelopes.

In the review, the quality of energy is veryrarely mentioned in the different strategiesand policies of the countries. In somecountries, however, there are aims toreduce the use of electricity for heating. InSweden it is prohibited for new buildings,and in Finland the use of electrical heatingsystems tightens the demand for heatconsumption. The primary energy factor issometimes also used to indicate thedifference of quality between energysources. Similarly, requirements forreducing the use of electricity in buildingshave been set only in some countries sofar. This aim should be applied in buildingcodes more widely in different countries.Building services systems and equipmentshould be developed further, taking intoaccount their electrical efficiency.

High quality energy should not be usedfor heating and cooling in buildings withouta thorough investigation of suitablealternatives. For instance in Germany and

the Netherlands the positive impacts of lowtemperature heating have already beentaken into account in building energyperformance calculations.

The new European energy performancedirective for buildings will help steering thenational codes into the right direction. It stillleaves relatively free hands to the individualcountries to decide how the targets will berealised in practice. It considers only newbuildings and renovations of large existingbuildings (over 1000 m2). This still leavesout a large part of the building stock. Inaddition, these regulations are only bindingon the European countries.

Renewables are supported in manycountries. The use of renewable sources isusually rewarded in the calculationmethods. This is also required by the newEuropean energy performance directive forbuildings. Poor insulation or ventilationenergy losses can usually be compensatedby the use of renewables.

One should not forget that rationalpassive design is a prerequisite for realisinglow exergy systems for the heating andcooling of buildings. All improvements inthe energy performance of the building willwork in favor of LowEx systems, becausethey can provide moderate heat or colddemand easier. Also, as we saw in Chapter2, the reduction of exergy use is mosteffectively done by a rational passivedesign of the building.

7. STRATEGIES AND POLICIES

A summary of a review of

strategies and policies in different

countries is presented in this

Summary Report. The country

specific reviews can be found in

the Guidebook. The review of

strategies and policies in different

countries shows that there is a

common aim to reduce the

demand of energy use in buildings.

In the future it is obvious that a

total approach will be used which

takes into account the use of

primary energy, the quality of

energy as well as environmental

impacts. Meanwhile, further

reduction of the specific needs for

energy use in buildings is

recommended.

CONCLUSIONS 41

8. CONCLUSIONS

The classical exergy analysis enables topinpoint the location, to understand thecause, and to establish the true magnitudeof waste and loss. Exergy analysis istherefore an important tool for the design ofthermal systems since it provides thedesigner with additional information onwhere and why the losses occur. Thedesigner can then proceed forward andwork on how to improve the thermalsystem. Application of exergy analysis intobuildings has not been usual before theimplementation of Annex 37. Tools forexergy analysis of buildings weredeveloped during the working time ofAnnex 37.

Exergy analysis can also be applied tohuman body to find optimal thermalconditions. Studies show that the lowesthuman body exergy consumption occurs atthermally neutral condition. Exergyconsumption within the human bodybecomes higher in a cold environment dueto larger difference in temperature betweenthe human body and its surrounding spaceand also becomes higher in a hotenvironment mainly due to sweating. Thesefindings suggest that heating and coolingsystems may also work well in suchconditions where the lowest amount ofexergy is consumed by those systems.That is, we may be able to establish boththermal comfort and low-exergy consumingsystems at the same time. The humanbody exergy analyses have now juststarted to articulate why LowEx systemsare essential for creating rational andcomfortable built environment.

There are currently many LowExtechnologies available. Low temperaturesystems successfully combine bothtraditional and innovative new approachesto heating. Usually the heat is transferredinto the room through air or liquidcirculation systems and the same systemcan often be used for both heating andcooling.

Research shows that people living inhouses with low temperature heatingsystems are very satisfied with ambientindoor air quality. In particular, thermal

Exergy defines the quality of

energy and is an important tool for

designing and assessing different

heating and cooling systems. In

Annex 37, 'low exergy (or LowEx)

systems' are defined as heating or

cooling systems that allow the use

of low valued energy as the energy

source. In practice, this means

systems that provide heating or

cooling energy at a temperature

close to room temperature. Low

temperature heating systems or

high temperature cooling systems

that are suitable for office

buildings, service buildings and

residential buildings, can use a

variety of fuels and renewable

energy sources. These systems

use energy efficiently while

providing a comfortable indoor

climate. They should be widely

implemented now in order to

create possibility to use

sustainable energy sources in the

near future.

comfort levels are considered to be higherthan in houses with a traditional heatingsystem. Residents also experienced areduction in draughts and dust, andreported fresher air in houses with lowtemperature heating systems. Theadvantages and disadvantages, mentionedby the occupants in the survey conductedduring Annex 37, are similar to results in theliterature. Also experiences from the casestudies supported the findings fromliterature and the occupants' survey.

By using low temperature heatingsystems the room temperature can bedecreased by a few degrees, which is moreenergy efficient and healthier for occupants.Low temperature heating systems do notusually require radiators, which can beunsightly and hard to clean. This offers theadditional advantages of increased livingspace and more flexibility in terms ofinterior design. Safety can also beimproved during the heating season due toabsence of hot radiator surfaces.

Low temperature heating systems aresustainable because they are flexible.These systems are not bound to any oneenergy source and fuel switching does notentail excessive cost. Low temperaturesystems can utilise a variety of sources ofheat including district heat, biofuel, solarenergy, gas, oil or electricity, and so theuser is not constrained by choices made inthe planning phase.

Thorough planning and expertimplementation are prerequisites for anappropriate and functional system. Systemflexibility will be dependent on the choice ofappliances and overall system design,which can be difficult and expensive tochange after installation.

Low temperature heat distributionsystems have an operating life of at least30-40 years during which time the userbenefits from the economic advantagesoffered by flexibility of fuel choice. The lifecycle costs of a low temperature heatingsystem are about the same as of atraditional system. Although the initialinvestment might be slightly higher, thesystem offers increased flexibility in terms offuel choice and increased energy

42 LOWEX GUIDEBOOK

efficiency. For example the efficiency ofsolar heating is considerably higher in a lowtemperature heating system than in atraditional one.

The demonstration projects of Annex 37show the wide variety of possibilities toapply low exergy heating and coolingsystems in buildings. There are examples oflow exergy systems in dwellings andoffices, but also in a museum and aconcert hall.

The application of LowEx systemsprovides many additional benefits besidesenergy supply such as: improved thermalcomfort, improved indoor air quality and

reduced energy consumption. Theseaspects should be further promoted toincrease the application of LowEx systemsfor heating and cooling of buildings. Thebuilding regulations and energy strategiesshould take the quality of energy intoaccount more than today.

Wide application of LowEx heating andcooling systems in buildings will create abuilding stock, which will be able to adaptto use of sustainable energy sources, whendesired. Without this ability, the transfertowards an energy-wise sustainable worldwill be delayed for decades.

43REFERENCES

9. REFERENCES

Ahern, J. 1980. The exergy Method of Energy system Analysis. Wiley-Interscience Publica-tion, John Wiley and Sons, New York.

Asada, H. and Shukuya, M. 1999. ‘Numerical Analysis of Annual Exergy Consumption forDaylighting, Electric-Lighting, and Space Heating/Cooling System’. Sixth InternationalIBPSA Conference (BS’99), Kyoto Japan, pp. 121-127.

Asada, H. and Takeda, H. 2002. ‘Thermal environment and exergy analysis of a ceilingradiant cooling system, Proceedings of Sustainable Buildings 2002, International Confer-ence, No. 561, Oslo, Norway, 23-25 September, 2002.

ASHRAE, 1997. Fundamentals, SI Edition, Energy Estimating and Modeling Methods.American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Atlanta,GA.

Baehr, H.D. 1980. Zur Thermodynamik des Heizens- I. Der zweite Hauptsatz und diekonventionellen Heizsysteme. Brennstoff-Wärme-Kraft, Germany, Vol. 32, No. 1, pp. 9-15.

Cornelissen, R.L. 1997. Thermodynamics and Sustainable Development – The Use ofExergy Analysis and the Reduction of Irreversibilities. PhD Thesis. University of Twente, TheNetherlands. ISBN 90 365 1053 8.

DIN 4701-10. 2001. Energy Efficiency of Heating and Ventilation Systems in Buildings –Part 10: Heating, Domestic hot Water, Ventilation. German national Standard. Berlin:Deutsches Institut für Normung e.V.

ECBCS 2002. Energy Conservation in Buildings and Community Service Programme.International Energy Agency. Web Homepage: http://www.ecbcs.org

Eijdems, H.H.E.W. and Boerstra, A.C. 1999. Kwalitatieve aspecten van lage temperatuurwarmte-afgifte systemen. Cauberg-Huygen and BBA. Amsterdam, NL.

Eijdems, H.H.E.W., Op’t Veld, P. and Boerstra, A.C. 2000. Literature review: Side effectsof Low Exergy emission systems. Working report of Annex 37.

François, C., Hammache, A., Schmidt, D., Shukuya, M. and Zirngibl, J. 2004a. User-Guidefor the Educational Tool for Energy and Exergy analyses of Heating and Cooling Applica-tions in Buildings. Annex 37 working report.

François, C., Hammache, A., Schmidt, D., Shukuya, M. and Zirngibl, J. 2004b. User-Guide for the Pre-Design Tool for Energy and Exergy analyses of Heating and CoolingApplications in Buildings. Annex 37 working report.

Gertis, K. 1995. Realistische Betrachtung statt ideologoischer Wünsche. Niedrigenergie-oder Niedrigentropiehäuser? Clima Commerce International CCI, Promoter VerlagKarlsruhe, Germany, Vol. 29, No 4, pp. 134-136.

Hammache, A. and Shukuya, M. 2004. Heating and cooling examples with the Pre-DesignTool for Energy and Exergy Analyses of Heating and Cooling Applications in Buildings. Acase study with the pre-design tool developed for IEA ECBCS Annex 37.

Isawa K., Komizo T. and Shukuya M. 2002. Low Exergy Systems Will Provide us with theLowest Human-Body Exergy Consumption and Thermal Comfort. LowEx News,publication of IEA Annex 37, No. 5; July 2002: pp 5-6.

Jenni, J. and Hawkins, A. 2002. Der Unterschied zwischen Temperatur und Energie – Oderwas kann mit exergiegerechter Speicherladung und -entladung erreicht werden? Heizung-Klima, Switzerland, Vol. 29, No. 3, 2002, pp. 8-11.

Klemp, P. 1997. Exergetische Analyse unterschiedlicher Kälte- und Wärmebereitstellungs-verfahren. Internal working report, Instiut für Angewandte Thermodynamik, University ofEssen, Germany.

44 LOWEXGUIDEBOOK

Maas, A., Hauser, G. and Höttges, K. 2002. Die Energieeinsparverordnung. Bauphysik,Publisher Ernst & Sohn, Germany, Vol. 24, No. 1, pp. 26-38.

Malovrh, M. and Praznik, M. 2002. Overview of knowledge on and experiences with lowtemperature heating in historical buildings in Slovenia. Paper presented in the LowExxworkshop in Maastricht in March, 2002.

Moran, M.J. 1989. Availability Analysis – a Guide to Efficient Energy use. CorrectedEdition. ASME Press, New York.

Moran, M.J. and Shapiro, H.N. 1998. Fundamentals of Engineering Thermodynamics. 3rdEdition, John Wiley & Sons, New York, USA.

Nishikawa, R. and Shukuya, M. 1999. ‘Numerical Analysis on the Production of CoolExergy by Making Use of Heat Capacity of Building Envelopes’. Sixth International IBPSAConference (BS’99), Kyoto Japan, pp. 129-135.

Saito, M. and Shukuya, M. 2000. ‘Exergy Balance of Human Body and Thermal Comfort’.Journal of Architectural Planning and Environmental Engineering, Architectural Institute ofJapan, No. 535, pp. 17-23 (in Japanese with English abstract).

Saito, M., Isawa, K., Komizo,T. and Shukuya, M. 2002. "The Relationship Between ExergyConsumption Within the Human Body and Thermal Sensation - Part 2. Exergyconsumption due to shivering and sweating, Annual Meeting of Architectural Institute ofJapan, Building Science Section, pp. 573-574.

Schmidt, D. 2001. Models for Coupled Heat and Mass Transfer Processes in Buildings –Applications to Achieve Low Exergy Room Conditioning. Tekn. Lic. Thesis. ISRN KTH-BYT/R-01/185-SE, KTH. Stockholm, Sweden.

Schmidt, D. 2004. Design of Low Exergy Buildings - Method and a Pre-Design Tool.International Journal of Low Energy and Sustainable Buildings, Vol. 3, 2003.

Shukuya, M. and Hammache, A. 2002. Introduction to the concept of Exergy – for abetter understanding of low-temperature-heating and high-temperature-cooling systems.Espoo: Technical Research Centre of Finland. 14 p. + app. 17 p. VTT Research Notes2158, ISBN 951-38-6074-4.

Shukuya, M. 1994. ‘Energy, Entropy, Exergy and Space Heating Systems’, Proceedings ofthe 3rd International Conference “Healthy Buildings ’94", Vol. 1, pp. 369-374.

Silvester, S., de Vries G. and Op’t Veld, P. 2000. Occupants’ experiences in dwellings withdifferents LT heating systems. Internal report of IEA ECBCS Annex 37. 17 p.

Steimle, F. (ed.) 2000. Handbuch haustechnische Planung. Krämer Verlag, Stuttgart,Germany.

Wall, G. 1986. Exergy – a Useful Concept. PhD Thesis. Chalmers University of TechnologyGothenburg, Sweden.

45PARTICIPATING COUNTRIES

A. PARTICIPATING COUNTRIES

OPERATING AGENTMarkku VirtanenVTT Building and TransportP.O. Box 180002044 VTTPhone: +358 9 695 90 672Mobile: +358 50 596 7690Fax: +358 9 695 90 666E-mail: [email protected]

CANADAAlain LegaultNatural Resources Canada1615 Lionel-BouletVarennes Quebec J3X 1S6Phone: +450-652-7031Fax: +450-652-0999E-mail: [email protected]

DENMARKBjarne W. OlesenInternational Centre for Indoor Environmentand Energy Technical University of DenmarkDepartment of Mechanical EngineeringNils Koppels Allé, Building 402DK-2800 Kgs. LyngbyPhone: +45-45254117Fax: +45-45932166E-mail: [email protected]

FINLANDMia Ala-JuuselaVTT Building and TransportP.O. Box 1800FIN-02044 VTTPhone: +358 9 456 6947Fax: +358 9 455 2408E-mail: [email protected]

FRANCEJohann ZirngiblCentre Scientifique et Technique duBâtiment (CSTB)84 avenue Jean JaurèsChamps-sur-Marne BP 2F-77421 Marne la Vallée Cedex 2,Phone: +33 1 64 68 8312Fax: +33 1 64 68 8350E-mail: [email protected]

GERMANYLars KühlTU BraunschweigMühlenpfordstr. 23D-38106 BraunschweigPhone: +49 531 391 3553Fax: +49 531 391 8125E-mail: [email protected]

Central contacts for the participa-

ting countries are presented here.

For an extended list of participants,

see the CD-ROM version of the

Guidebook.

ITALYGaetano FasanoENEA- ENEvia Anguillarese, 30100060 RomePhone: +39 06 3048 4827Fax: +39 06 3048 3700E-mail: [email protected]

JAPANMasanori ShukuyaMusashi Institute of Technology3-1, Ushikubo-Nishi 3-chome,Tsuzuki-kuYokohama 224-0015Phone: +81-45-910-2552Fax: +81-45-910-2553E-mail: [email protected]

NETHERLANDSPaul RamsakNovemP.O. Box 176130 AA SittardPhone: +31 46 4202275Fax: +31 46 4528260E-mail: [email protected]

NORWAYPer GundersenNorwegian Building Research InstituteP.O. Box 123 Blindern0314 OsloPhone: +47 22 965553Fax: +47 22 965725E-mail: [email protected]

POLANDJanusz SkorekDivision of Thermodynamics and GasEnergy Institute of Thermal TechnologyTechnical University of SilesiaKonarskiego 2244-100 GliwicePhone: +48 32 237-24-27Fax: +48 32 237-28-72E-mail: [email protected]

SWEDENGudni JóhannessonKTH Building TechnologyBrinellvägen 34S-10044 StockholmPhone: +46 8 790 8670Mobile: +46 70 595 3037Fax: +46 8 411 8432E-mail: [email protected]

Dietrich SchmidtKTH Building TechnologyBrinellvägen 34S-10044 StockholmPhone: +46 8 790 8716Fax: +46 8 411 8432E-mail: [email protected]

A1

46 LOWEX GUIDEBOOK

B. COMPANY AND PRODUCT INFORMATION

FFFFFINLAND

Fläkt Woods

FINLAND

Business Area: A specialist in AirClimate and Air Ventilation, offering acomprehensive range of components,products and solutions. Fläkt Woods is aglobal ventilation pioneer and partner.Local precence in 95 countries.Main products: Ventilation products andservices for Buildings and Industry.

P.O.Box 5FIN-02621 EspooContact: Peter SundelinEmail: [email protected]: +358 20 4423000Mobile: +358 40 8683299Fax: +358 20 4423303

Business Area: ARE’s business operationsextend from designing to maintenance ofbuilding services.Main products: Building services systems.

P.O.Box 160FIN-001611 VantaaContact: Heikki Mäki.Email: [email protected]: +358 20 530 5606Fax: +358 20 530 5101Web: http://www.are.fi

ARE Oy

B1

Uponor Suomi Oy Business Area: Manufactures and marketsa wide range of plastic pipe systems forpotable water and gas distribution, for hotwater distribution and heating as well assewer systems for both municipalinfrastructures and the house buildingsector.Main products: plastic pipes and systemsused for underfloor heating, radiatorconnections and tap water installations inhouses and buildings, pipe systems tomunicipalities, public utilities and stateauthorities for water supply, sewage, andstorm water drainage, completeI systems in polyethylene, polypropylene orpolyvinyl chloride for freshwater supply, soiland waste discharge, and cable protection.

P.O.Box 21FIN-15561 NastolaContact: Jarmo Mäenpää.Email: [email protected]: +358 3 885 0270Web: http://www.uponor.com

47COMPANY AND PRODUCT INFORMATION

JAPAN

PS Company, Ltd.

Hans-Böckler-Ring 4122851 NorderstedtPhone: 0049 40 / 3 09 86-0Fax: 0049 40 / 3 09 86-433Web: http://www.velta.de

Wirsbo-VELTA GmbH & Co. KG

Business area: manufacturing, engineeringcompany specialising in radiant heating andcooling systems. Main products: plasticpipes and systems used for underfloor /ceiling heating and cooling.

GERMANY

1-1-1 Tomigaya, Shibuya-ku, Tokyo,151-0063, JAPANContact: Dr. Yoshihisa HirayamaPhone: +81-3-3485-8494Fax: +81-3-3485-8779E-mail: [email protected]: http://www.ps-group.co.jp/

Business area: manufacturing, engineeringcompany specialising in radiant heating andcooling systems, humidification systemsHead Office: TokyoOffice: Sapporo, Morioka, Sendai,Nagano, Niigata, Tokyo, Nagoya, Osaka,Fukuoka, and KumamotoFactory: Sapporo, Iwate, TokyoMain products: heating and coolingradiator systems, humidifiers, dehumidifiers

Uponor-Velta GmbH & Co. KG

Business area: development and distri-bution of software tool and reserachprojects in the field of energy efficientbuilding, further education in the field ofsustainable and energy effcient buildingMain products: software and courses

Gottschalkstrasse 28a34127 KasselContact: Jürgen LaudenbachPhone: + 49 561 804 3189Fax + 49 561 804 3187Web: www.zub-kassel.de

Zentrum für UmweltbewusstesBauen e.V. (ZUB)

B2

48 LOWEX GUIDEBOOK

BROCHUREThe Brochure ”Low Temperature Heating Systems – Increased Energy Efficiency andImproved Comfort” gives an overview of the systems, some case examples and a shortintroduction of the LowEx project.

GUIDEBOOK AS PDFA printable .pdf version of the Guidebook is available for those who prefer a paper version.The CD-ROM version, however, offers the user some additional opportunities in movingaround in the Guidebook and includes some additional information.

SUMMARY REPORT AS PDFThe Summary Report introducing the Guidebook is available on the CD-ROM.

INTRODUCTION TO EXERGYShukuya, M. and Hammache, A. 2002. Introduction to the concept of Exergy – for abetter understanding of low-temperature-heating and high-temperature-cooling systems,VTT Research Notes, 21582158215821582158, Technical Research Centre of Finland, Espoo.

This document was prepared during Annex 37. It describes the exergy concept, presentsthe basic principles of exergy analysis and gives examples of exergy calculation, especiallyin connection with heating and cooling systems of buildings.

LOWEX NEWSThe Annex 37 working group produced a newsletter twice yearly during the working phaseof Annex 37. The first issue was published in September 2000 and last in December 2003.From the CD-ROM you can get the .pdf-versions of all the eight issues of LowEx News. Ashort description of the contents of each newsletter is provided on the CD-ROM.

LITERATURE REVIEWEijdems, H.H.E.W, Op’t Veld, P. and Boerstra, A.C. 2000. Literature review: Side effects ofLow Exergy emission systems. Working report of Annex 37.

In this study the characteristics of LTH emission systems are compared with those of atraditional system based on radiators or air heating with water at 90/70 °C. This compari-son is used for assessing the merits of a low temperature heat source, with particularreference to themal comfort, IAQ and energy performance.

OCCUPANTS’ EXPERIENCESSilvester, S., de Vries, G. and Op’t Veld, P. 2000. Occupants’ experiences in dwellingswith differents LT heating systems. Internal report of IEA ECBCS Annex 37. 17 pages.

The objective of the occupant survey was to make an inventory of the experiences ofoccupants with LT systems and to look if these systems fulfil the expectations ofoccupants.

CASE RELATED ARTICLESSome LowEx case related articles are available at the CD-ROM for those, who areinterested to learn more about the case buildings.

PUBLISHED ARTICLESA list of the exergy related articles published by the members of Annex 37 working group isgiven on the CD-ROM. Some of the articles are even included in the CD-ROM.

C. ADDITIONAL INFORMATION

On the CD-ROM version of the

Guidebook you can find the

following additional information.

C1

49ADDITIONAL INFORMATION

TECHNICAL PRESENTATIONSTechnical presentations were prepared for the ECBCS ExCo meetings during the workingtime of Annex 37. Reports are available on the CD-ROM.

TOOLSBoth of the Exergy Analysis Tools described in Chapter 4 of the Guidebook are available onthe CD-ROM.

TOOL MANUALSUser-Guides for both of the Exergy Analysis Tools described in Chapter 4 of the Guidebookare available on the CD-ROM.

LOWEXXSelected documents from the LowExx project. There was a special project for LowExsystems in existing buildings. In this project the possibilities of LowEx systems in existingand historical buildings (LowExx) were investigated. Experiences from the Netherlands,Slovenia, Finland and Greece were brought together and discussed in a LowExx-workshopheld in Maastricht, the Netherlands on March 2002.

LOWEXNETThe Annex 37 working group considered it very important to continue the working togetherto further promote the use of exergy concept in connection with buildings. The discussionsduring the Annex 37 Expert meeting in Kassel led to the founding of the InternationalSociety for Low Exergy Systems in Buildings (short LowExNet) on the 13th September2003. The main objective of this network is to formulate our interest in the regarded topicsbeyond the working time of the IEA Annex 37 itself. It is planned to have workshops inconnection with other international events. The first LowExNet Workshop was held inRovaniemi, Finland in connection with the last Annex 37 meeting. It is planned to discussnew and also forgotten-ancient concepts, technologies and applications of LowExsystems. LowExNet will cover applications in countries outside the IEA, like those in LatinAmerica and Africa. All information will be available on a website (http://www.lowex.net/).

C2

50 LOWEX GUIDEBOOK

D. PUBLISHED ARTICLES

A list of over forty exergy related publications by the members of the Annex 37 WorkingGroup can be found in the Guidebook. Some articles are available on the CD-ROM.

D 1

33333

22222

This Summary Report summarises andpresents the contents of the Guidebook,which is included here in CD-ROM format.

The Guidebook is meant to helpengineering offices, consultants andarchitects in their search for energy efficientheating and cooling systems that canprovide the occupants with comfortable,clean and healthy environment. In addition,some background information is offered forreal estate builders, building maintenancemanagers, political decision makers andthe public at large. The Guidebook isavailable as a CD-rom version and alsofreely available on the internet (http://www.lowex.net/).

LowEx, the international low


research programme, is part of

the International Energy Agency’s

(IEA) Energy Conservation in

Buildings and Community

Systems programme (ECBCS).

The aim of the programme was to

promote rational use of energy by

encouraging the use of low


and high temperature cooling

systems of buildings.

Exergy defines the quality of energy andis an important tool for designing andassessing different heating and coolingsystems. In Annex 37, ‘low exergy(LowEx) systems’ are defined as heating orcooling systems that allow the use of lowvalued energy as the energy source. Inpractice, this means systems that provideheating or cooling energy at a temperatureclose to room temperature. Lowtemperature heating systems or hightemperature cooling systems that aresuitable for office buildings, servicebuildings and residential buildings, can usea variety of fuels and renewable energysources. These systems use energyefficiently while providing a comfortableindoor climate. They should be widelyimplemented now in order to createpossibility to use sustainable energysources in the near future.

LOWEX GUIDEBOOK

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Documents

Fraunhofer IBP - HEATING AND COOLING WITH FOCUS ON · 2020-08-08 · Application of exergy analysis into buildings has not been common before the implementation of Annex 37. Tools