CONTENTS · Reference Buildings for Cost-Optimal Analysis: the activities of the TEBE Research Group March 8th 2012 S.P. Corgnati, E. Fabrizio, M. Filippi 2 1. FOREWORD The European

Reference Buildings for Cost-Optimal Analysis: the activities of the TEBE Research GroupMarch 8th 2012 S.P. Corgnati, E. Fabrizio, M. Filippi

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CONTENTS1. FOREWORD2. EXAMPLES OF REFERENCE BUILDINGS2.1. Reference Building n.1: Multi-family Residential Building2.1.1. Description2.1.2. Packages of Measures2.2. Reference Building n.2: Medium Office Building2.2.1. Description2.2.2. Packages of Measures2.3. Reference Building n.3: Large Office Building2.3.1. Description2.3.2. Results3. FURTHER STEPS TOWARDS A COMPLETE DATABASE OF REFERENCE BUILDINGS4. REFERENCES


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1. FOREWORDThe European Directive on the energy performance of buildings (EPBD recast) defined all newbuildings will be nearly zero-energy buildings by the end of 2020. Buildings with a very highenergy performance are thus expected to be assessed by all Member States. The comparativemethodology framework provided by the EPBD recast, requires Member State to calculatecost-optimal levels of minimum energy performance for new and existing buildings. In orderto apply the methodology Member State are also expected to define reference buildings to beused as baseline and representative models of the national building stock.This report aims to provide a brief overview of the research activities, related to the EPBDrecast, on-going within TEBE research team (Technology Energy Building Environment), ledby prof. Marco Filippi in the Department of Energy (DENERG) at the Politecnico di Torino.The dynamic energy simulation group, with reference to the EPBD recast, deals especiallywith the topic of minimum optimal level of energy performance in connection to the globalcost. The activities in progress investigate the assessment of building energy performance onthe basis of the cost-optimal analysis suggested by the EPBD recast. Moreover the researchteam aims to create a set of reference buildings, representative of Italian building stock to beused into the cost-optimality calculations. The reference buildings created are also used asmodels to investigate the concept of nearly zero energy buildings by means of dynamic energysimulation.


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2. EXAMPLES OF REFERENCE BUILDINGSSome examples of Reference Buildings for Italy have been produced. In particular threereference buildings have been defined:1) A Multi-family buildings/Apartments block;2) A medium office building;3) A large office building.The data used for defining the buildings have been gathered in terms of geometry, technicalsystems and usage patterns.Reference building n.1 is a Real Building as it is actually a real existing building, with averagecharacteristics based on statistical analysis. Reference building n.2 is a theoretical building asthe definition of the building is based on statistical survey. Reference building n.3 is anexemplar building as it was developed on experts’ assumptions. Thereby they differ in thesources all data have been extracted from.

Figure 4.1 – Timeline for the selection of Reference BuildingsBesides using different data source for the definition of each buildings, the reference buildinguntil now developed are also relevant as they are representative of different period. Asoutlined in the figure above, each reference building describe a different context in terms ofconstruction technologies used and also in terms of energy policy in Italy. The timeline placesthe reference buildings developed by TEBE group into certain age periods, thus selected for amajor relevance in terms of expansion of the building stock and for the evolution of energy


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regulations applied to the building sector. The multi-family reference building is a realbuilding, built in the ‘60s, hence it is the result of the major reconstruction of the post-WorldWar II. Moreover it is characterized by construction technologies with no insulation, as allbuildings built in that age.Whereas the medium office building is representative of a more recent contruction age, from1992 until now. It is thus characterized with construction technologies with a major regard tothe thermal losses. In conclusion the large office building as it is a reference for newconstruction, can be placed at the end of the timeline. It is in fact representative of the currentdesign approach of the office building stock.The models here presented can be considered representative of climate zones D, E and F, inNorthern Italy.With regard to the operation level, some overarching assumptions were made common to allreference buildings in order to use reference patterns and establish some boundaryconditions. Schedules referring to the usage of the building, especially within the samecategory of reference building, as for the office models, were set referring to the sameStandard and Design Manuals. They are listed as follows: Occupancy Schedule (EN 15232, 2007); Lighting Schedule (Maria Pia Arredi, 2004).For all reference buildings, ambient conditions (i.e. heating and cooling temperature) were setaccording to national standard 10339. Moreover, with regard to the building construction,thermal transmittance values and thermal mass values were defined in compliance withnational regulations (D.lgs 311/2006, D.P.R. 59/2009) for all reference buildings.Internal gain values, as referring to the office building category, were set according to thefollowing references:- People, National Standard UNI 10339;- Lighting power densities, EN 15193, 2008;- Equipment power densities, EN 15232, 2007.

In addition the definition of the packages of measures have been carried out with a similarapproach in order to create a common database of measures to be applied to different


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reference buildings. Up to now, measures only regarding the building envelope have beeninvestigated.Overall, packages have been divided into two categories depending on the type of measureapplied:- homogenous packages: measures applied to the whole building.- non-homogeneous packages: measures applied to a few building elements.Moreover packages have been named differently according to the level of observance of thecurrent regulation in terms of energy consumption applied to building design:- Packages named “Standard requirements” are in compliance with the minimumrequirements of the national and local law; their measures are listed with a *;- Packages “Plus 1 Standard requirements” provide measures that exceed the minimumlaw requirements and that are marked with **;- Packages named “Plus 2 Standard requirements”, are made up by outstandingmeasures, that go beyond those of “Standard requirements plus 1” and marked with***;- Packages named “Highly insulated plus” are made up by high insulation measures,marked with ****.Energy rates used for all reference buildings were also set according to processed data of theRegulatory Authority for Electricity and Gas (AEEG) in Italy .Energy pricesNatural gas (Residential) 0,7205 €/m3Natural gas (Office) 0,7280 € /m3Electricity (Residential) 0,1750 €/kWhElectricity (Office) 0,2035 €/kWhThe lifecycle period for the global cost calculation has been set to 50 years for the multi-familyreference buildings and the medium office reference building. An inflation rate1 of 2,17% hasbeen assumed on the basis of mean national values.

1 The inflation rate used is an average of the mean values of CIA World Factbook and of Internationl MonetaryFund, in the decade 1999-2010.


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2.1. Reference Building n.1: Multi-family Residential Building

2.1.1. DescriptionMulti-family houses emerged, from statistical analysis, to be the most common residentialbuildings in Italian context as this building category has been selected for the referencebuilding here described.As explained above, this reference building is a Real Building as it is an existing building builtin the subarea of Turin. It has been chosen as it has average characteristics of buildingsbelonging to that category (multi-family houses). The data used for its definition werecollected within IEE project, TABULA as Italy participated as project partner.The characteristics of the building are presented in the table and figures below.Reference Building – Apartment Block

Build

ing

Description The building is a residential apartment block. It consist of 24 equal apartmentsand 4 floors above grounds. It has also a basement and an attic both notconditioned.Geometry

External dimensions 12,60 x 37,50 mGross Floor Area 472,50 m2Apartment gross floor Area 73,45 m2Room height 3,10 mN-E Façade Exterior wall area 170,10 m2S-E Façade Exterior wall area 383,70 m2Window area 122,58 m2S-O Façade Exterior wall area 170,10 m2N-O Façade Exterior wall area 326,30 m2Window area 94,06 m2EnvelopeComponents

Opaque elements Exterior Wall 1,15 W/m2KFlat ceiling under the roof 1,65 W/m2KSlab towards nonconditioned basement 1,30 W/m2KTransparent Elements Window 4,90 W/m2K

Syst

em Heating system Gas boiler with radiators.The setpoint temperatures are 20°C from 7 a.m. until 8 p.m., and 18°C duringthe remaining hours.Ventilation The infiltration rate is 0,5 ACH and is constant during all days.

Ope

rati

on Internal Gains People 0,04 person/m2Appliance (incl. Lighting) 4 W/m2


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Figure 4.2- Picture of the real building.

Figure 4.3 - Typical floor plan, Multi-family building.

Figure 4.4 - Thermal zones, Multi-family building.2.1.2. Packages of MeasuresBy now 9 packages of measures (plus the baseline reference building) concerning thebuilding envelope have been defined. All packages have been set in compliance with thecurrent national and local energy regulations.Homogenous packages, from level 1 to level 3, are composed of measures applied to allbuilding elements. Whilst non-homogeneous packages, from level 4 to level 9, is composed ofmeasures applied only to a few building elements. All packages of measures are listed in thetable below.


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PACKAGES OFMEASURES

LEVEL 0REFERENCEBUILDING (1,15 W/m2K) (4,9 W/m2K) (1,30 W/m2K) (1,65 W/m2K)LEVEL 1STANDARDREQUIREMENTS *(0,32 W/m2K) *(1,7 W/m2K) *(0,3 W/m2K) *(0,3 W/m2K)LEVEL 2PLUS 1REQUIREMENTS * *(0,25 W/m2K) * *(1,2 W/m2K) * *(0,22 W/m2K) * *(0,23 W/m2K)LEVEL 3HIGHLYINSULATEDPLUS

* * * *(0,17 W/m2K) * * * *(1,2 W/m2K) * * * *(0,17 W/m2K) * * * *(1,2 W/m2K)LEVEL 4STANDARDREQUIREMENTS *(0,32 W/m2K) *(1,7 W/m2K)LEVEL 5STANDARDREQUIREMENTS *(0,32 W/m2K) *(0,3 W/m2K) *(0,3 W/m2K)LEVEL 6STANDARDREQUIREMENTS *(1,7 W/m2K)LEVEL 7PLUS 1REQUIREMENTS * *(0,25 W/m2K) * *(1,2 W/m2K)LEVEL 8PLUS 1REQUIREMENTS * *(0,25 W/m2K) * *(0,22 W/m2K) * *(0,23 W/m2K)LEVEL 9HIGHLYINSULATEDPLUS * * * *(0,17 W/m2K) * * * *(1,2 W/m2K)

LEVEL 10HIGHLYINSULATEDPLUS * * * *(0,17 W/m2K) * * * *(0,17 W/m2K) * * * *(1,2 W/m2K)


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2.2. Reference Building n.2: Medium Office Building

2.2.1. DescriptionThis reference building has been modeled on the basis of a statistical survey carried out byENEA (Italian National Agency for New Technologies Energy and Sustainable EconomicExpansion). All data concerning the building level (type, geometry, size, layout, envelopecharacteristics) as well as system level have thus been extracted from the statistics mentionedabove, hence the office building is a Theorical Building. Indeed data related to the buildingusage, have indeed been defined on experts’ assumption and national standards, as stated inthe boundary conditions mentioned previously.The characteristics of the Reference Building are outlined in the Table and sketches below.Reference Building - Office Building

Build

ing

Description The building, referred as medium office, has a total gross area of 2,400 m2 and 5floors above ground. The interior layout is defined by cellular offices on theperimetric areas and a central core for the distributive elements (stairs andelevators) and service areas.

GeometryExternal dimensions 16x30 mGross Floor Area 480 m2Total Gross Area 2400 m2Height 2,9 mNorthern Façade Exterior wall area 278 m2Window area 157,50 m2Southern Façade Exterior wall area 278 m2Window area 157,50 m2Western Façade Exterior wall area 232 m2Window area 140 m2Eastern Façade Exterior wall area 232 m2Window area 140 m2EnvelopeComponents Opaque elements Exterior Wall 0,761 W/ m2 KRoof 0,828 W/ m2 KUnderground slab 0,516 W/ m2 KTransparent Elements Window 3,19 W/ m2 K

Syst

em

HVAC 4 pipes fancoils with outside airHeating system Gas boiler (80°C)Heating setpoint 21,5°C from 5 a.m. until 6 p.m., and 15°C in remaining hours, during week days.Cooling system Water-cooled chillerCooling setpoint 26°C from 5 a.m. until 6 p.m. during week day;Turn off during the remaining hours.Ventilation 11 l/s per person,Air flow is assumed to be constant from 5 a.m. until 6 p.m during week days.

Ope

rati

on Internal Gains People The occupancy rate for offices id 0,06 person/m2.Lighting 13 W/m2 during working days. A 0,5 percentageis assumed during weekends and night time forsecurity systems.Equipment 10 W/m2 during working days.


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Figure 4.5 – Axonometric View, Medium Office

Figure 4.6 - Typical floor plan, Medium Office

Figure 4.7 - Thermal Zones, Medium Office


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2.2.2. Packages of Measures

PACKAGES OFMEASURES

LEVEL 0REFERENCEBUILDINGLEVEL 1STANDARDREQUIREMENTS *(0,33 W/m2K) *(0,3 W/m2K) *(1,9 W/m2K) *(0,28 W/m2K)LEVEL 2PLUS 1REQUIREMENTS * *(0,25 W/m2K) * *(0,23 W/m2K) * *(1,65 W/m2K) * *(0,23 W/m2K)LEVEL 3PLUS 2REQUIREMENTS * * *(0,15 W/m2K) * * *(0,15 W/m2K) * * *(1,25 W/m2K) * * *(0,15 W/m2K)LEVEL 4HIGHLY INSULATEDPLUS * * * *(0,14 W/m2K) * * * *(0,11 W/m2K) * * * *(0,83W/m2K) * * * *(0,11 W/m2K)LEVEL 5HIGHLY INSULATEDPLUS * * * *(0,11 W/m2K) * * * *(0,11 W/m2K)LEVEL 6HIGHLY INSULATED * * * *(0,83 W/m2K)LEVEL 7HIGHLY INSULATED * * * *(0,11W/m2K) * * * *(0,83 W/m2K)LEVEL 8HIGHLY INSULATED * * * *(0,14 W/m2K) * * * *(0,83 W/m2K)LEVEL 9COMBINEDHIGHLY INSULATED-STANDARDREQUIREMENTS

*(0,33 W/m2K) * * * *(0,11 W/m2K) * * * *(0,83W/m2K) *(0,28 W/m2K)LEVEL 10COMBINEDHIGHLY INSULATED-PLUS 1REQUIREMENTS

* *(0,25 W/m2K) * * * *(0,11 W/m2K) * * * *(0,83W/m2K) * *(0,23 W/m2K)


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2.3. Reference Building n.3: Large Office Building

2.3.1. DescriptionThis third reference building is large office building created on the basis of DOE benchmarkbuilding models. DOE US Large office have thus been contextualized to the Italian territory interms of construction and technological tradition as well as of Italian Standard and energyregulations.The procedure pursued to define the reference building, as representative of Italiancommercial building stock, is outlined in three major steps as follows:1) Analysis and study of U.S. models and the methodology followed for their definition;2) Research over offices built in Italy in order to investigate their main features (e.g. planshape and layout, envelope thermal parameters, comfort parameters, schedules, HVACequipment) and to define a building model that can be adopted as representative of Italianlarge offices;3) Definition of a reference model in compliance with Italian standard and energyregulations, across seven different location (representing climate zone E, in the NorthenItaly).As all data concerning the creation of the reference building have been on experts’ assumption(e.g. Design manuals, architecture reviews, national standards, etc), this reference building isan Example building.The characteristics of the Reference Building are outlined in the Table and sketches below.Reference Building – Large Office Building

Build

ing

Description The building, referred as large office, has a total gross area of 46320 m2 and 12floors above ground, plus a basement. The interior layout is defined by openoffices on the perimetric areas and a central core for service areas, and officesas well.

GeometryExternal dimensions 48x73 mGross Floor Area 3563 m2Total Gross Area 46’320 m2Floor to Floor Height 2,74 mNorthern Façade Exterior wall area 2090 m2Window area 1391 m2Southern Façade Exterior wall area 2090 m2Window area 1391 m2Western Façade Exterior wall area 1389 m2Window area 927 m2Eastern Façade Exterior wall area 1389 m2Window area 927 m2Envelope Opaque elements Exterior Wall 0,309 W/ m2 K


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Components Roof 0,248 W/ m2 KUnderground slab 0,638 W/ m2 KTransparent Elements Window 1,1 W/ m2 KSy

stem

HVAC Multi-zone VAV with fancoilsHeating system Gas boiler (80°C)Heating setpoint 21°C from 5a.m. until 7p.m., and 15,6°C in remaining hours, during weekdays.Cooling system 2 Water cooled chillersCooling setpoint 24°C from 5 a.m. until 6 p.m. during weekdays; 30 °C during the remaininghours.Ventilation 0,10 ACH.Air flow is assumed to be constant from 6 a.m. until 10 p.m during weekdays.

Ope

rati

on Internal Gains People The occupancy rate for offices id 0,06 person/m2.Lighting 15 W/m2 during weekdays.Equipment 10 W/m2 during weekdays.

Figure 4.8 - Axonometric View, Large Office

Figure 4.10 - Thermal Zones. Large Office.


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3. FURTHER STEPS TOWARDS A COMPLETE DATABASE OF REFERENCEBUILDINGS

More studies about the definition of reference building for other building categories arecurrently being carried on. Especially a representative model for the school categories is beinganalyzed.Future studied will deal with the definition of reference building for new construction for theoffice building categories as well as for the residential sector.The reference buildings above described will also be used to investigate the concept of nearlyzero energy buildings by means of dynamic energy simulation.


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4. REFERENCES1) Ballarini, I. Corgnati, S.P. Corrado, V. Talà, N. Definition of building typologiesfor energy investigations on residential sector by TABULA IEE-project: applicationto italian case studies, In: RoomVent 2011, Trondheim, 19-22 June 2011.2) E. Fabrizio, D. Guglielmino, V. Monetti, Italian benchmark building models: the office building,in V. Soebarto, H. Bennetts, P. Bannister, P.C. Thomas, D. Leach (a cura di), “Driving better designthrough simulation”, IBPSA Australia & AIRAH, Melbourne, 2011, pp. 1981-1988 (ISBN 978-0-646-56510-1);

3) C. Becchio, D. Guglielmino, E. Fabrizio, M. Filippi, Whole cost analysis of building envelopetechnologies according to the European Standard EN 15459, Climamed ’11 VI CongresoMediterraneo de Climatizacion, Madrid 2-3 giugno 2011, ATECYR, pp. 291-306 (ISBN 978-84-95010-41-4).

Documents

CONTENTS · Reference Buildings for Cost-Optimal Analysis: the activities of the TEBE Research Group March 8th 2012 S.P. Corgnati, E. Fabrizio, M. Filippi 2 1. FOREWORD The European