Towards Zero Energy Buildings

Bjarne W. Olesen, Technical University of Denmark

Per Heiselberg, Aalborg University

Outline

• 0:00 European and US actions towards ZEB (Bjarne)

• 0:12 European Definition of nZEB (Per)

• 0:17 Experience with low energy buildings (Per)

• 0:25 Energy Efficient Ventilation of Buildings (Per)

• 0:40 Energy efficient Heating and Cooling of buildings (Bjarne)

• 0:55 Q&A

European and US actions

towards ZEB

• Building codes and standards

• Energy performance directive

• Renewable energy requirements

• Requirements to products and components

Role of the Building Sector ¨’

40 % of EU’s energy use

36 % of EU’s CO2 emissions

Cost-effective energy savings potential: ~30 % by

2020

9 % of GDP, 8 % of employment and

€2 trillion annual turnover

4/12

Comprehensive set of legislation to enhance energy efficiency

.Directive for the taxation of energy products and electricity

. Energy end-use efficiency and energy services Directive Services

.Directive on the promotion of cogeneration Generation

Buildings . Energy performance of buildings Directive

(EPBD)

.Directive establishing a framework for the setting of eco-design requirements for energy-using products (implementing directives for e.g. boilers, refrigerators, freezers and ballasts for fluorescent lighting

Eco-Design

.Directives for labelling of e.g. electric ovens, air-conditioners, refrigerators and other domestic appliances . Regulation of Energy Star labelling for office equipment

Product

Labelling

Taxation 5/14

The 20-20-20 EU policy by 2020

Greenhouse

gas levels

Energy

consumption

Renewables in

energy mix

-20% -20%

100%

20%

8,5%

Required reductions in

energy use in European

countries

2020 in relation to 2005

Directive 2009/28/EC (Renewable Energy Directive 2009) of the

European Parliament and of the Council of 23 April 2009 on the

promotion of the use of energy from renewable sources

National overall targets for the share of energy from renewable

sources in gross final consumption of energy in 2020

• Hungary 4,3 % 13 %

• Malta 0,0 % 10 %

• Netherlands 2,4 % 14 %

• Austria 23,3 % 34 %

• Poland 7,2 % 15 %

• Portugal 20,5 % 31 %

• Romania 17,8 % 24 %

• Slovenia 16,0 % 25 %

• Slovak Republic6,7 %14 %

• Finland 28,5 % 38 %

• Sweden 39,8 % 49 %

• United Kingdom 1,3 % 15 %

Belgium 2,2 13 %

Bulgaria 9,4 16 %

Czech Republic 6,1 13 %

Denmark 17,0 30 %

Germany 5,8 18 %

Estonia 18,0 25 %

Ireland 3,1 16 %

Greece 6,9 18 %

Spain 8,7 20 %

France 10,3 23 %

Italy 5,2 17 %

Cyprus 2,9 13 %

Latvia 32,6 40 %

Lithuania 15,0 23 %

Luxembourg 0,9 11 %

2005-2020 2005-2020

Part of renewable energy sources

(wind and bio-fuel) in Denmark

Comprehensive set of legislation to enhance energy efficiency

.Directive for the taxation of energy products and electricity

. Energy end-use efficiency and energy services Directive Services

.Directive on the promotion of cogeneration Generation

Buildings . Energy performance of buildings Directive

(EPBD)

.Directive establishing a framework for the setting of eco-design requirements for energy-using products (implementing directives for e.g. boilers, refrigerators, freezers and ballasts for fluorescent lighting

Eco-Design

.Directives for labelling of e.g. electric ovens, air-conditioners, refrigerators and other domestic appliances . Regulation of Energy Star labelling for office equipment

Product

Labelling

Taxation 11/14

Energy Performance of Buildings Directive – EPBD (2002/91/EC)

Requirements - for Member States to specify and implement:

An integrated methodology to rate the energy performance of

buildings

Minimum energy performance standards for new and for

existing buildings that undergo major renovation

Energy performance certificates for buildings

Regular inspections of boilers and

air-conditioning systems

12/14

The effect og

building

regulations

US developments towards ZEB

• Often driven by private organization like

ASHRAE

• Very different from state to state

• Several states are reffering to ASHRAE standard

90.1

• California has the most strict criteria in their

California Building Standards Code ,Title 24

• DOE (department of Energy) want to have a

national definition of ZEB

ASHRAE’s contribution to ZEB

• Standards

• Handbooks

• Advange Energy Design Guides

Major Standards

under Review/Revision

ASHRAE-Energy Performance

Standards

• ANSI/ASHRAE/IES Standard 90.1-2013 -- Energy

Standard for Buildings Except Low-Rise Residential

Buildings

• ANSI/ASHRAE Standard 90.2-2007 - Energy Efficient

Design of Low-Rise Residential Buildings

• ANSI/ASHRAE/IES 100-2015 - Standard 100-2006.

Energy Efficiency in Existing Buildings

• ANSI/ASHRAE/USGBC/IES/ICC 189.1-2014 Standard

for the Design of High-Performance, Green Buildings

Except Low-Rise Residential Buildings

ANSI/ASHRAE/IES Standard 90.1-2013 -- Energy

Standard for Buildings Except Residential Buildings

20

Source: Pacific Northwest National Laboratory

Advanced Energy Design Guides:

522,000 in circulation

Four 50% AEDGs Being Implemented

•50% Grocery Stores

– Quick Serve Restaurants

– Places of Assembly

•Under Discussion

•Net Zero – K-12 Schools (2)

– Quick Serve Restaurants

– Places of Assembly

– “Net Zero Ready” Guidance

www.ashrae.org/freeaedg

Building Energy Quotient

• Free submissions offered to qualified ASHRAE

members until Nov. 30, 2014

• Expanded to allow submissions by professional

engineers in addition to ASHRAE-Certified

Building Energy Assessment Professional

(BEAP) or Building Energy Modeling

Professional (BEMP)

• Updated In Operation Workbook with more

consistent, streamlined procedures

• EPA-Energy Star rating???

ZEB Concept

Over the course of a year, if

the on-site renewable energy

produced ≥ the energy

consumed within the

boundary, it is considered a

ZEB

23

Site Energy (n)ZEB

A building where the actual annual delivered energy ≤ on-site

renewable exported energy as measured at the site.

24

Source Energy (n)ZEB

A building where the actual annual

delivered energy ≤ on-site renewable

exported energy as measured at the

building site and converted to source

energy.

25

Zero Energy Cost Building

A building where the actual annual energy costs are zero.

26

(Net) Zero Energy Building (ZEB) Definition

An energy-efficient building, where on a

source energy basis, the actual annual

delivered energy is less than or equal to the

on-site renewable exported energy.

27

EUROPEAN DEFINITION OF NZEB

Per Heiselberg

TIMELINE OF KEY EU LEGISLATION AFFECTING

ENERGY USE IN BUILDINGS

THE EU- DIRECTIVE ON ENERGY

PERFORMANCE OF BUILDINGS 2002

(IMPLEMENTED IN DK IN 2006)

THE GENERAL FRAMEWORK FOR A

METHODOLOGY OF CALCULATION OF THE

INTEGRATED ENERGY PERFORMANCE OF

BUILDINGS;

• The application of minimum requirements on the energy

performance of new buildings;

• The application of minimum requirements on the energy

performance of large existing buildings that are subject to

major renovation;

• Energy certification of buildings

• Regular inspection of boilers and of air-conditioning

systems in buildings and in addition an assessment of

the heating installation in which the boilers are more than

15 years old.

EU DIRECTIVE ON THE ENERGY PERFORMANCE

OF BUILDINGS

Def in i t ion

• The amount of energy actually consumed or estimated

to meet the different needs associated with a

standardised use of the building, which may include,

inter alia, heating, hot water heating, cooling,

ventilation and lighting.

• This amount shall be reflected in one or more numeric

indicators which have been calculated, taking into

account insulation, technical and installation

characteristics, design and positioning in relation to

climatic aspects, solar exposure and influence of

neighbouring structures, own-energy generation and

other factors, including indoor climate, that influence

the energy demand

ENERGY PERFORMANCE REQUIREMENTS TO BE SET WITH A V IEW

TO ACHIEVING COST OPTIMAL LEVELS USING A COMPARATIVE

METHODOLOGY FRAMEWORK

• Cost optimal performance is defined as the energy performance in terms of

primary energy leading to minimum life cycle cost.

EDBP RECAST ESTABLISHED THE TARGET OF NEARLY ZERO

ENERGY BUILDINGS ( NZEB) FOR ALL NEW BUILDINGS

• By 31 dec 2020, all new buildings are nearly zero energy buildings

• After 31 dec 2018, public authorities that occupy and own a new building shall

ensure that the buildings is a nearly zero energy building

EPBD RECAST

- TARGETS FOR COST OPTIMAL AND NZEB

EDBP RECAST

-DEFINITION OF NEARLY ZERO ENERGY

BUILDINGS

I n the d i rec t i ve “near ly ze ro energy bu i l d ings ” means a bu i l d ing tha t

has a ve ry h igh energy energy per fo rmance .

The near l y ze ro o r ve ry l ow amount o f energy requ i red shou ld be

covered to a ve ry s ign i f i can t ex ten t by energy f rom renewab le sources ,

i nc lud ing energy f rom renewab le sources p roduced on -s i te o r nearby

De f in i t i on o f “a ve ry h igh energy per fo rmance ” and “s ign i f i can t ex ten t

o f renewab les ” a re de f i ned by member s ta tes

NEARLY ZERO ENERGY BUILDING DEFINITION

NEARLY ZERO ENERGY

BUILDING DEFINIT ION SHALL

BE BASED ON DELIVERED

AND EXPORTED ENERGY

ACCORDING TO EPBD

RECAST AND EN 15603 :2008

ENERGY USE IN THE

BUILDINGS INCLUDES

ENERGY USED FOR

HEATING, COOLING,

VENTILATION, HOT WATER,

L IGHTING AND APPLIANCES.

THIS IS NEEDED FOR

CALCULATION OF EXPORTED

ENERGY OR TO ANALYZE

LOAD MATCHING AND GRID

INTERACTION OF NZEB

Total energy useof the building

Delivered energy

Exported energy

Building site = system boundary of delivered and exported energy

System boundary of building technical systems

BUILDING

NEEDSHeatingCooling

VentilationDHW

LightingAppliances

Building site boundary = system boundary of delivered and exported energy

Heating energy

Cooling energy

Electricity for

lighting

Fuels

ENERGY

USE

BUILDING

TECHNICAL SYSTEMS

Energy use and production

System losses

and conversions

Electricity

ON SITE RENEWABLE

ENERGY W/O FUELS

District heat

District cooling

Electricity

Solar gains/

loads

Heat

transmission

ENERGY NEED

DELIVERED

ENERGY

EXPORTED

ENERGY

(renewable and

non-renewable)

Electricity for

appliances

Internal heat

gains/loads

RE generators

He

atin

g e

n.

Ele

ctr

icity

Co

olin

g e

n.

Energy use SB

Cooling en.

Heating en.Energy need SB

Building site boundary = system boundary of delivered and exported energy

Fuels

Electricity

District heat

District cooling

Electricity

DELIVERED

ENERGY

EXPORTED

ENERGY

(renewable and

non-renewable)

Building 1

Cooling en.

Heating en.

Building 2

Building n

SITE ENERGY

CENTRE

EXPERIENCE WITH LOW ENERGY

BUILDINGS

Per Heiselberg

ENERGY USE HIGHER THAN EXPECTED

Based on 230.000 single family houses with energy labelling. Preliminary results not yet validated or published

Reference: Kirsten Gram-Hanssen, SBi 2015

HOME FOR LIFE, LYSTRUP, DENMARK

Home for life – Energy Concept

Home for life – Energy balance

60

Energy production solar thermal

and solar cells

-33

Hot water and

heating

-14

Electricity

household

-8

Electricity

technique

Energy need and production from solar [kwh/m2/year]

EXPERIENCES RELATED TO ENERGY USE AND

PRODUCTION

THE MOST IMPORTANT DEVIATIONS:

• Energy use for heating higher than expected

• Electricity use for heat pump higher than expected

• Electricity use for control system higher than expected

• Energy use DHW lower than expected

• Electricity use for appliances and plug loads lower than expected.

• Production from solar thermal system as expected

• Production from PV as expected

Reference: Esbensen, 2012

1. Measured

2. As 1, corrected for weather

3. As 2, corrected for indoor temperature

4. As 3, corrected for lower person load

5. As 4, corrected for domestic electricity use

6. As 5, corrected for air tightness

7. As 6, corrected for less efficient heat recovery 8. As 7, corrected for use of solar shading 9. As 8, corrected for measuring equipment and screens 10. As 9, corrected for DHW use 11. As 10, corrected for efficiency of heat pump 12. Predicted energy use

Reference: Esbensen, 2012

RELATIVE IMPORTANCE OF DIFFERENT

ASPECTS

Reference: Esbensen, 2012

Overheating – l iving room

Reference: Esbensen

32%

24%

32%

10%

2%

Living year 1

58% 26%

13%

1% 2%

Living year 2

59% 20%

14%

1%

6%

Sleeping, year 1

66%

18%

13%

1% 2%

Sleeping, year 2

Reference: VELUX og Esbensen

IMPACT OF IMPROVED CONTROL AND OPERATION

WHY DO WE FACE THESE CHALLENGES IN

HIGH PERFORMANCE BUILDINGS?

IT IS NOT POSSIBLE TO REACH GOALS THROUGH MORE

• Envelope insulation, Building airtightness, Ventilation heat recovery,

WHICH ARE ROBUST TECHNOLOGIES WITHOUT USER INTERACTION

NEW MEASURES NEEDS TO BE INCLUDED

• Demand controlled ventilation

• Shading for solar energy control

• Shading for daylighting control

• Lighting control

• Window opening

ALL TECHNOLOGIES:

• Where performance is very sensitive to control

• Which involve different degree of user interaction

• Whose function and performance are difficult for users to understand

WHY DO WE FACE THESE CHALLENGES IN

HIGH PERFORMANCE BUILDINGS?

THE PRIMARY OBJECTIVE OF USERS IS FULLFILLMENT OF

THEIR NEEDS ( INDOOR ENVIRONMENT) AND THEY WILL

ALWAYS ADJUST CONTROLS ACCORDINGLY.

THIS OFTEN LEADS TO HIGHER ENERGY USE AND POORER

INDOOR ENVIRONMENT THAN EXPECTED.

AUTOMATIC CONTROL SHOULD BE BETTER ADAPTED TO THE

FULLFILMENT OF USER NEEDS

PER HEISELBERG

ENERGY EFFICIENT VENTILATION OF

HIGH PERFORMANCE BUILDINGS

ENERGY EFFICIENT VENTILATION OF

HIGH PERFORMANCE BUILDINGS

ENERGY DEMAND IN TYPICAL OFFICE

BUILDING

Condit ions U-value: 1,5 W/m²K, g-value: 0,60, Lt-value: 0,70

SFP: 2,1 kJ/m³

Light control: Manual

Thermal mass: Light

30 % window area in relation to floor area

Infiltration 0,3 h-1

Cooling Heating

Lighting Ventilation

Misc.

Energy demand distribution

Total energy demand 96 kWh/m²

ADDITIONAL CHALLENGES IN HIGH

PERFORMANCE BUILDINGS

The cu r ren t deve lopmen t towards nea r l y - zero energy bu i l d i n g s h ave l e ad to :

an i n c rea sed need for coo l i n g – no t on l y i n summer bu t a l l y e a r

• Increased potential for using the cooling potential of outdoor air

An reduc t ion o f E l e c t r i c i t y u se fo r a i r t r an spor t becomes i n c rea s i n g l y

impor t an t

• Increased use of natural/hybrid ventilation

• Distribution of cold air to rooms without creating discomfort

• Effective decentralized ventilation solutions

SIX DIFFERENT AIR DISTRIBUTION SYSTEMS

-Tested in the same geometry and with the same load

pvn@civil.auc.dk

qo - ∆To Design Chart

WIDEX/WESSBERG A/S

WIDEX/WESSBERG A/S

SOLBJERGSKOLEN SOUTHWEST OF ÅRHUS

SYSTEM PRINCIPLE

DRAUGHT RISK

• Winter condition: supply air temperature -8 oC,

ACH =4

DR <20%

ISO 7730

VENTILATION SOLUTIONS

Building

Use Outdoor

Climate

Building

Design

IAQ

Thermal Comfort

Internal loads

Micro-

climate

Natural ventilation

Mechanical ventilation

Air Conditioning

Hybrid

ventilation

Occupant

Profile

RATIONALE FOR HYBRID VENTILATION

• HAS ACCESS TO BOTH VENTILATION MODES

IN ONE SYSTEM, EXPLOITS THE BENEFITS OF

EACH MODE AND CREATES NEW

OPPORTUNIT IES FOR FURTHER

OPTIMISATION AND IMPROVEMENT OF THE

OVERALL QUALITY OF VENTILATION.

• FULFILS THE HIGH REQUIREMENTS ON

INDOOR ENVIRONMENTAL PERFORMANCE

AND THE INCREASING NEED FOR ENERGY

SAVINGS AND SUSTAINABLE DEVELOPMENT.

• RESULTS IN H IGH USER SATISFACTION

BECAUSE OF THE HIGH DEGREE OF

INDIV IDUAL CONTROL AS WELL AS A DIRECT

AND V IS IBLE RESPONSE TO USER

INTERVENTIONS.

• OFFERS AN INTELLIGENT AND ADVANCED

VENTILATION SOLUTION FOR THE COMPLEX

BUILDING DEVELOPMENTS OF TODAY, THAT

IS USER TRANSPARENT AND SUSTAINABLE.

HYBRID VENTILATION STRATEGIES

Al te rna t i ng o r comb ined na tu ra l and mechan ica l ven t i la t ion

– This principle is based on a combination of two fully autonomous systems where the control strategy consists of switching between or combining both systems.

– It covers fx systems with natural ventilation in the intermediate seasons and mechanical ventilation during midsummer and/or midwinter or it covers systems with mechanical ventilation for workstations during occupied hours and natural ventilation for building and night cooling.

INSTITUTE OF DEVELOPMENT ECONOMIES

(JETRO), CHIBA, J

Courtesy of:

Dr. Tomoyki Chikamoto, Nikken Sekkei Ltd, Japan

Heat fromTask Zone

Supply fan unitfor Ambient Zone

Fresh air

Ambient Zone

Task Zone

CH C

EA (Exhaust Air)

OA (Outside Air)

Personal supply outlet for Task Zone(D air to human body)irect supply of fresh

Effective exhaustion ofheat and pollutant

CH COA

Personal AC system for Task Zone

Higher temp.upply jets

Under-floor AC systemfor Ambient Zone

20℃

22℃22℃

28℃26℃

High IAQ andthermal comfort

Pollutant fromTask Zone

26℃

30℃

HYBRID VENTILATION AND AIR CONDITIONING

SYSTEM

Automatically controlled window

- This opening is also used for smoke exhaust

opening in case of fire

Ambient

supply unit

Task supply unit

- Air volume and direction are

easily changed by each user

HYBRID VENTILATION AND AIR CONDITIONING

SYSTEM

Fresh air

Ambient Zone

Task Zone

CH C

EA (Exhaust Air)

OA (Outside Air)

CH COA

Air volume and direction are easily

changed by each user.

Task supply unit is detachable.

Ambient zone is controlled mildly by

central BA system for energy saving.

Task zone is controlled by each one’s

choice for human’s comfort.

Warm air

Cool air

CONTROL OF HYBRID VENTILATION AND AIR

CONDITIONING SYSTEM

HYBRID VENTILATION STRATEGIES

STACK AND WIND SUPPORTED MECHANICAL

VENTILATION

– This principle is based on a mechanical ventilation

system, which makes optimal use of natural driving

forces.

– It covers mechanical ventilation systems with very

small pressure losses where natural driving forces

can account for a considerable part of the necessary

pressure difference.

N

M

Mediå School, Grong, Norway

Courtesy of:

Professor Per Olaf Tjelflaat, Norwegian University for

Science and Technology, Trondheim, Norway

AIR SUPPLY SYSTEM

AIR EXHAUST SYSTEM

Mediå School, Grong, Norway

LOW PRESSURE LOSS IN SYSTEM

• VENTILATION SUPPLY ABOUT 35 PA

– Filter about 15 pa

– Heat recovery about 10 pa

– Heating about 5 pa

• VENTILATION EXHAUST ABOUT 20 PA

– Heat recovery about 12 pa

TOTAL PRESSURE LOSS WINTER ABOUT 55 PA

TOTAL PRESSURE LOSS SUMMER ABOUT 28 PA

PRESSURE LOSS SUMMER (WITHOUT FILTER) ABOUT 13 PA

Energy efficient Heating and

Cooling of buildings

• Low temperature Heating-High Temperature Cooling

• Water based systems

• Radiant heating and cooling ceiling panels

• Thermo Active Building Systems (TABS)

• Chilled beams

• Floor heating and cooling

Low-Temperature heating

High-Temperature Cooling

• Heat exchange through large surfaces

(floor, ceiling, walls)

• Supply water temperatures:

– Heating: 25 – 40 °C

– Cooling: 16 – 23 °C (temperature limited by

dew-point to avoid condensation)

• Wide range of systems, solutions both for

residential and non-residential buildings

74

Sustainability

75

• Higher efficiency of boilers and chillers

• Lower distribution looses

• Better use of renewable energy sources

– Ground heat exchangers

– Waste heat from processes

– Dry coolers

– Heat pumps

• Low energy consumption for

circulation

• Low exergy

CONCEPTS OF RADIANT HEATING AND

COOLING SYSTEMS

• Minimum 50% heat exchange by radiation

• Heating - cooling panels

• Surface systems

• Embedded systems

• Most recent development is the increasing

application world wide.

Suspended cooled ceilings

System types

Water as the heat carrier

Heat exchange is > 50% radiant

Different installation concepts

(thermally coupled or insulated form the building structure)

78

THERMO ACTIVE BUILDING SYSTEMS (TABS)

Trend started in nineties in Switzerland, typically used in Europe

Suitable primarily for sensible cooling and for base heating

Installed in the centre of concrete slab between the reinforcements

Diameter of the pipes varies between 17 and 20 mm

The distance between pipes is within the range 150 - 200 mm

Installed during the main building construction with prefabricated slabs.

Reinforcement

Floor

Concrete

Pipes

Window

Room

Room

Concept of

Thermo Active Building Systems

Concept of

Thermo Active Building Systems (TABS) EXAMPLE OF INTERNAL CONDITIONS WITH THERMAL SLAB

20

21

22

23

24

25

26

27

28

29

30

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.0

0

11.0

0

12.0

0

13.0

0

14.0

0

15.0

0

16.0

0

17.0

0

18.0

0

19.0

0

20.0

0

21.0

0

22.0

0

23.0

00.

00

TE

MP

ER

AT

UR

E [

°C]

-1

-0.5

0

0.5

1

PR

ED

ICT

ED

ME

AN

VO

TE

T floor

PMV

T airT mr

T water return

T ceiling

COMBINATION WITH LOW ENERGY

SOURCES

UPONOR Corporation (2010)

Heating supply temp. : 25 - 40°C

heat pumps

condensing boiler

ground coupling

waste heat

solar energy

Cooling supply temp. : 16 - 23°C

reversible heat pump

ground coupling

free cooling

air cooled chillers 82

Day

Night

Cooling method

Ground water

Geothermal

heat/coolth

Night air

Cooling unit

Additional benefits – large atriums and

foyers

83

The under-floor cooling system directly removes solar heat gains

Minimum of such gains influences air temperature

Comfortable floor surface temperature is maintained at the same time

Airport Bangkok

Airport Bangkok

June 30 2008

Terminal building

Balanced Office Building

Aachen, Germany

• Gross floor area 2,151 m²

• 4 storeys

• Efficiently insulated external envelope

• Ground-coupled heating and cooling with TABS

• Ventilation system with heat recovery

• Daylight-controlled lighting

• Rainwater collection for use in toilet flushing

Energy concept

cooling period

0

5000

10000

15000

20000

25000

30000

35000

Heizung Kühlung Lüftung Beleuchtung Pumpen Warmwasser Summe

Yearl

y e

nerg

ie c

osts

[€/m

²a]

Bestand

BOB.1

Energy efficiency

94 % energy saving compared with conventional

cooling

60 % energy saving for lighting by daylight

steering

The need of energy for heating, cooling, air-

ventilation lighting and warm water is 27,8

kWh/m² per year

Energy costs per m², per year: 2,7 EUR,

per month 22,5 Cent

Office Building in Madrid, Spainain

91

16 000 m2

Natural & Mechanical ventilation

External solar shading & green

facade

TABS combinned with free cooling

(covers 40-50 kWh/m2)

(kWh/m²y) Actual CTE - MADRID %

Heating + DHW 27,35 77,00 -64,5

Cooling 12,58 85,00 -85,2

Lighting 11,37 34,00 -66,6

Total 51,30 196,00 -73,8

Energy use

Office Building in Madrid, Spain

92

Chilled Beams Water based distribution

Chilled Beams

Chilled Beams

Water based distribution

Low Exergy Hydronic Radiant Heating and Cooling

Why?

• Water based systems

• Low temperature heating - High temperature cooling

• More economical to move heat by water:

– Greater heat capacity than air

– Much smaller diameter pipes than air-ducts

– Electrical consumption for circulation pump is lower than for fans

• Lower noise level

• Less risk for draught

• Lower building height for TABS

• Higher efficiency of energy plant

• But

– Reduced capacity?

– Acoustic?

– Latent load?

VENTILATIVE COOLING

P E R H E I S E L B E R G

D E P A R T M E N T O F C I V I L E N G I N E E R I N G

DEFINITION OF VENTILATIVE COOLING

VENTILATIVE COOLING IS APPLICATION (DISTRIBUTION IN

T IME AND SPACE) OF VENTILATION AIR FLOW TO REDUCE

COOLING LOADS IN BUILDINGS

VENTILATIVE COOLING UTILIZES THE COOLING AND

THERMAL PERCEPTION POTENTIAL (HIGHER AIR

VELOCITIES) OF OUTDOOR AIR

IN VENTILATIVE COOLING THE AIR DRIVING FORCE CAN BE

NATURAL, MECHANICAL OR A COMBINATION

VENTILATIVE COOLING IS A SOLUTION

THE DEVELOPMENT TOWARDS ”NEAR ZERO ENERGY BUILDINGS ”

HAS RESULTED IN AN INCREASED NEED FOR COOLING – NOT ONLY

IN SUMMER BUT MOST OF THE YEAR!

VENTILATIVE COOLING CAN BE AN ATTRACTIVE AND ENERGY

EFFICIENT PASSIVE SOLUTION TO REDUCE COOLING AND AVOID

OVERHEATING.

• Ventilation is already present in most buildings through mechanical and/or

natural systems using opening of windows

• Ventilative cooling can both remove excess heat gains as well as increase air

velocities and thereby widen the thermal comfort range.

• The possibilities of utilizing the free cooling potential of low temperature

outdoor air increases considerably as cooling becomes a need not only in the

summer period.

POTENTIAL AND LIMITATIONS

OUTDOOR CLIMATE POTENTIAL

• Outdoor temperature lower than the thermal comfort limit in large part of the

year in many locations

• Especially night temperatures are below comfort limits

• Natural systems can provide “zero” energy cooling in many buildings

L IMITATIONS

• Temperature increase due to climate change might reduce potential

• Peak summer conditions and periods with high humidity reduce the potential

• An urban location might reduce cooling potential (heat island) as well as

natural driving forces (higher temperature and lower wind speed). Elevated

noise and pollutions levels are also present in urban environments

• Building design, fire regulations, security are issues that might decrease the

use of natural systems

• High energy use for air transport limit the potential for use of mechanical

systems

Annex 62 Ventilative Cooling

IEA EBC Annex 62

Ventilative Cooling

Annex 62 Ventilative Cooling

Annex Objectives

• To analyse, develop and evaluate suitable methods and tools for

prediction of cooling need, ventilative cooling performance and risk

of overheating in buildings that are suitable for design purposes.

• To give guidelines for integration of ventilative cooling in energy

performance calculation methods and regulations including

specification and verification of key performance indicators.

• To extend the boundaries of existing ventilation solutions and their

control strategies and to develop recommendations for flexible and

reliable ventilative cooling solutions that can create comfortable

conditions under a wide range of climatic conditions.

• To demonstrate the performance of ventilative cooling solutions

through analysis and evaluation of well-documented case studies.

Annex 62 Ventilative Cooling

Annex Outcome

• Guidelines for energy-efficient reduction of the risk of overheating by ventilative cooling

• Guidelines for ventilative cooling design and operation in residential and commercial buildings

• Recommendation for integration of ventilative cooling in legislation, standards, design briefs as well as on energy performance calculation and verification methods

• New ventilative cooling solutions including their control strategies as well as improvement of capacity of existing systems

• Documented performance of ventilative cooling systems in case studies

Annex 62 Ventilative Cooling

Annex Leadership

• Participating countries – Austria, Belgium, China, Denmark, Ireland, Italy, Japan, Netherlands,

Norway, Portugal, Switzerland, UK, USA

• Operating Agent: – Denmark, represented by Per Heiselberg, Aalborg University

• Subtask A: – Leader: Switzerland, represented by Fourentzos Flourentzou, ESTIA

– Co-leader: Italy, represented by Annamaria Belleri, EURAC

• Subtask B: – Leader: Austria, represented by Peter Holzer, IBRI

– Co-leader: Denmark, represented by Theofanis Psomas, AAU

• Subtask C: – Leader: China, represented by Guoqiang Zhang, Hunan University

– Co-leader: Ireland, represented by Paul O’Sullivan, CIT

DIFFUSE CEILING VENTILATION

P E R H E I S E L B E R G

D E P A R T M E N T O F C I V I L E N G I N E E R I N G

COOLING IN OFFICES AND EDUCATIONAL

BUILDINGS

WITH HIGH INSULATION AND A IR T IGHTNESS LEVELS ALWAYS A

COOLING NEED DURING OCCUPIED HOURS EVEN IN THE WINTER

SEASON

COOLING IS NOT A NEW TECHNOLOGY, BUT THE NEED FOR

COOLING IS INCREASING AND MORE EFFICIENT SYSTEMS HAVE TO

BE DEVELOPED TO FULFILL FUTURE ENERGY REQUIREMENTS

APPLICATION OF THE FREE COOLING POTENTIAL OF OUTDOOR AIR

IS WIDELY USED IN MECHANICAL VENTILATION SYSTEMS, BUT

HIGH A IR FLOW RATES ARE NEEDED IN WINTER BECAUSE OF

DRAUGHT RISK LEADING TO RELATIVELY HIGH ENERGY USE FOR

A IR TRANSPORT

WHAT IS DIFFUSE CEILING VENTILATION

THE SPACE ABOVE A SUSPENDED CEIL ING IS USED AS A PLENUM

AND FRESH A IR IS SUPPLIED TO THE OCCUPIED ZONE THROUGH

PERFORATED SUSPENDED CEIL ING.

THE PRINCIPLE

Rockfon / Troldtekt ceiling

Ecophon ceiling

Fully diffuse ceiling

SIX DIFFERENT AIR DISTRIBUTION SYSTEMS

-Tested in the same geometry and with the same load

pvn@civil.auc.dk

QO - ∆TO DESIGN CHART

WIDEX/WESSBERG A/S

WIDEX/WESSBERG A/S

SOLBJERGSKOLEN SOUTHWEST OF ÅRHUS

SYSTEM PRINCIPLE

DRAUGHT RISK

• Winter condition: supply air temperature -8 oC, ACH =4

DR <20% ISO 7730

HEAT LOAD LOCATION

Evenly distributed Center

Front side Back side

VELOCITY DISTRIBUTION

DRAUGHT RISK

0

2

4

6

8

10

12

14

16

18

20

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

DR

[%

]

Distance from inlet [m]

Evenly Center

Front side Back side

ROOM HEIGHT

2.335 m 3.0 m 4.0 m

VELOCITY DISTRIBUTION

2.335 m 3.0 m 4.0 m

DRAUGHT RISK

0

2

4

6

8

10

12

14

16

18

20

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

DR

[%

]

Distance from inlet [m]

2.335 m

3.0 m

4.0 m

DIFFUSE CEILING OPENING AREA

100% DF 18% DF

VELOCITY DISTRIBUTION

100% DF 18% DF

DRAUGHT RISK

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4 5

DR

[%

]

Distance from inlet [m]

0.1 m

0.6 m

1.1 m

1.7 m

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4 5

DR

[%

] Distance from inlet [m]

0.1 m

0.6 m

1.1 m

1.7 m

100% DF 18% DF

CONCLUSION

Low draught risk in the occupied zone even, when supplying air at

temperatures below 0Co

Air distribution and draught risk dependent on heat load location, ceiling

height, area and location of supply.

Very low vertical temperature gradient in the room with diffuse celling

supply

Low radiant temperature asymmetry and no clear radiation cooling

potential of diffuse ceiling, due to low conductivity

Very low pressure drop across diffuse ceiling (less than 5 Pa)