n.k. tovey ( 杜伟贤 ) m.a, phd, ceng, mice, cenv Н.К.Тови М.А., д-р...

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N.K. Tovey (杜伟贤 ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук

Recipient of James Watt Gold Medal

1

Control of Energy use in Buildings Building Regulations

CLIMATE CHANGE GOVERNANCE AND COMPLIANCE

NBS-M017/NBSLM04D 2012 version 2

Session2

U-Value Specification with different Regulations

2

1976 1985 1990 1994 2000 2005 2010

U – Values W m-2 oC-1

SAP < 60

SAP > 60

External Wall 1.0 0.6 0.45 0.45 0.35 0.45 0.35 0.35

Roof 0.6 0.35 0.25 0.2 0.16 0.25 0.16 0.16

Floor 1.0 0.6 0.45 0.35 0.25 0.45 0.25 0.25

Windows Not specified 3.0 2.0* 3.3 2.0 2.0

Windows as % of external walls

17% 12% -

Windows as % of total floor areas

- - 15% 22.5% 25% 22.5% 25% 25%

Comparison of energy consumption for a standard detached house at various ages and improvements (Heat losses in W0C-1)

0

100

200

300

400

500

600

700

800

pre-war

post-war

1960s 1976 1985 1990 1994 2000

unimproved

25mm

50mm

100mm

100+CAV

100+DG

100+DG+CAV

150+DG

200+DG+CAV

250+DG+CAV

DG – double glazingCAV – cavity wall insulationNumerical value indicates thickness of loft insulation 3

Compliance to Building Regulations

• Compliance to Building Regulations may be achieved by one of several alternative methods.

– Elemental Method

• Specifies maximum U-value and perhaps maximum glazed area – valid until 2002 Regs

- still used in several other countries

– Target U-value – weighted average U-value allowed some flexibility in design

– SAP Rating (1994 Regs) – economic assessment

– Carbon Index (2002 Regs)

– Target Emission Rate (Current Regs)

4

2006 Regulations Dwelling Emission Rate is method of compliance- essentially the 2010 Regs are similar with only minor variations in detail

• Criterion 1

• A Dwelling Emission Rating (DER) must be calculated taking due account of the U-values, the size, the types of heating etc using the Standard Assessment Procedure (SAP)

• The DER must be shown to be less than the Target Emission Rating (TER) which is computed with the same size of building and U-values meeting those as specified in the Regulations.

Essentially this is a derivative of the target U – value method

• Details are shown in Section 2.1.11 of handout5

Criterion 2 – limits on design flexibility• Performance of the building must not be worse than a

given standard. • gives considerable latitude in design – the old trade-off

problem.

• However criterion attempts to limit this type of trade-off – see pages 5 and 6 of the Approved Document

Criterion 3 – Limiting effects of solar overheating• Requires that the effects of overheating in summer must be

addressed

6


Criterion 4 Quality of Construction• Criterion requires evidence of actual performance – e.g.

changes arising from design modifications, quality of workmanship.

Some of the requirements involve pressure testing the building to ensure they have achieved those used in the design specification.

Criterion 5. Providing Information• Requires information on the maintenance and operation of

the building to be made available.

7


CALCULATION of SAP RATING

• While the Standard Assessment Procedure makes sense the final Rating known as the SAP Rating creates problems

• The SAP rating is related to the total energy cost by the equations:

• Energy Cost Factor (ECF)

= deflator × total energy cost / (TFA + 45) (10)

• The total energy running cost includes not only heating but also requirements for hot water, lighting etc as well as pumps/fans associated with heating. These are proscribed costs according to a table which are not actual costs.

• The deflator is a factor which varies according to energy costs and is intended to keep SAP Ratings constant with time irrespective of changes in fuel prices - this has not been the case in the past. But this still causes problems with relative changes between different fuels

8

SAP Rating 20092005SAP

Mains gas

LPG Oil Electricity Solid mineral

Biomass

1 1 10 1 6 12 910 9 20 9 16 21 1820 19 31 19 26 31 2830 29 41 29 37 41 3740 39 50 39 46 50 4750 48 59 50 56 59 5660 58 68 60 65 68 6570 67 76 70 74 77 7480 76 84 80 82 85 8390 85 92 90 91 93 92

100 94 99 100 99 100 100

Impact of Changing Methodology on SAP Rating

These changes are relatively small compared with changes in previous methodology changes – i.e. 1995 – 2001 and 2001 – 2006.However these demonstrate the problem of using Economic Cost as a Key Factor in determining the SAP Rating 9

Climatic Issue with 2010 Calculations

10

Calculations have to take account of Climate Variations of Solar Gain for

Assessment of Cooling Requirements

But NOT Heating (even though heating requirements will vary by up to +/-25% from one part of country to another

Benefit of Solar Panels does not account for geographic variations in solar radiation even though this information is available for cooling calculations.

Indian Building Code• WEBSITE: http://www.hareda.gov.in/ECBC.pdf

• Also available at UEA at

– http://www2.env.uea.ac.uk/gmmc/energy/NBS-M14x/Indian_DRAFTECBC27MARCH2006.pdf

11

Code was formulated following Energy Conservation Act of 2001

According to Saurabh Kumar, Secretary of Ministry of Power (18th April 2007), Code was to be trialled in demonstration areas from July 2007

An initial appraisal suggests that code tends to follow the equivalent of an Elemental Approach, but with differences

Unlike UK, elemental standards vary from region to region according to climate.

UK has 18 zones each with different Degree-Days, but elemental standards are same

[Technically Scotland could modify standards in Scotland]

Two identical houses in UK, one in South West, the other in North East Scotland, the energy consumption for space heating in latter would be 47% higher than former

12Is it sensible to have different standards in different climate regimes?

Indian Building Code

Climate Zone Hospitals, Hotels, Call Centers (24-Hour)

Other Building Types (Daytime)

Maximum U-factor (W/m2 oC-1)

Maximum U-factor (W/m2 oC-1)

Composite 0.352 0.352

Hot and Dry 0.369 0.352

Warm and Humid 0.352 0.352

Moderate 0.431 0.397

Cold 0.369 0.352 13

Example of U-values for walls

Based on Table 4.3.2 of ECBC 2006.Note: The U-value in the UK is 0.35 W/m2 oC-1

Indian Building Code

14

Chinese Building Code

China is adopting a similar approach to that suggested for India

Country/District U-Values (W m-2 oC -1)

Walls Windows Roof

Beijing (2003) 0.82 – 1.16 3.5 0.6 – 0.8

Beijing (current) 0.6

Shanghai (current) 1.0

Germany 0.5 1.5 0.22

Sweden 0.17 2.5 0.12

UK (2005 Regulations) 0.35 2.0 0.16

Canada 0.36 2.86 0.23 – 0.4

Hokk aido, Japan 0.42 2.33 0.23

Zones in USA similar to Beijing 0.32 – 0.45 2.04 0.19

Zones in Russia similar to Beijing

0.44 – 0.77 2.75 0.33 – 0.57

15

Chinese Building Code

Calculating the TER• TER2010 = (Ch x FF x EFAh + Cl xEFAl) x (1–0.2)* (1 – 0.25)

i.e. a 25% improvement on 2005 This is partly to bring things in align with Code for Sustainable Homes

* The (1 – 0.2) represents a carry over from TER-2005 which indicated a 20% improvement on 2002 Regulations

• Where

Ch are the carbon emissions associated with space heating and hot water including any used in circulating pumps,

Cl is the equivalent associated with lighting

FF is a fuel factor – this is NOT the Emission Factor for the Fuel

EFA is the relevant Emission Factor Adjustment and is a ratio of the emission factors used in the 2009 calculations divided by the equivalent ones in the 2005 calculations.

Improvements for 2010 - Environmental Impact Rating (EI)

Note: Error in handout page 21

16

• Letter Rating bands are assigned as followsIt applies to both the SAP rating and the Environmental

Impact rating (why the SAP Rating??). Rating Band

Improvements for 2010 - Environmental Impact Rating (EI)

EI Range Letter Rating

> 92 A

81 to 91 B

69 to 80 C

55 to 68 D

39 to 54 E

21 to 38 F

1 to 20 G

17

18

How has the performance of a typical house changed over the years?

Bungalow in South West Norwich built in mid 1950s

Original Construction

• Brick – brick cavity walls• Metal windows•Solid floor no insulation•No loft insulation

19

Annual Energy Consumption

0

5000

10000

15000

20000

25000

30000

Interwar

post-war

1960s 1976 1985 1990 1994 2002 2006

kWh

House constructed in mid 1950s

Part L first introduced

~>50% reduction

First attempt to address overall consumption. SAP introduced.

Changing Energy Requirements of House

In all years dimensions of house remain same – just insulation standards change

As houses have long replacement times, legacy of former regulations will affect ability to reduce carbon emissions in future

19

20

Annual Energy Consumption

0

5000

10000

15000

20000

25000

30000

Interwar

post-war

1960s 1976 1985 1990 1994 2002 2006 gas oil SAP2005

kWh


Existing house – current standard: gas boiler

Improvements to existing properties are limited because of in built structural issues – e.g. No floor insulation in example shown.

House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005.

As Existing but with oil boiler

Changing Energy Requirements of House

21

Annual CO2 Emissions

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

Interwar

post-war

1960s 1976 1985 1990 1994 2002 2006 gas oil SAP2005

CO

2 em

issi

ons

(kg)


Changing Carbon Dioxide Emissions

Existing house – current standard: gas boiler

As Existing but with oil boiler

Notice significant difference between using gas and oil boiler.

House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005. 21

22

• Introduced over next few years to improve standards to ultimate “zero carbon house”

• But objectives of a low carbon future may be jeopardised if attention is not also paid to sustainable transport associated with new dwellings

The Future: Code for Sustainable Homes

0

2000

4000

6000

8000

10000

12000

14000

16000

1

Lighting

Refrigeration

Entertainment

Miscellaneous

Air/Public Travel

Washing/Drying

Private Car

HeatingData for 1 household with 2 cars

23

The Code For Sustainable Homes

The Code for Sustainable Homes is a set of sustainable design principles covering performance in nine key

areas.

1. Energy and CO2

2. Water

3. Materials

4. Surface water run-off

5. Waste

6. Pollution

7. Heath and well being

8. Management

9. Ecology

9 key areas of performance….

http://www2.env.uea.ac.uk/cred/harrisongroup/Code_for_Sustainable_Homes.htm

24

Code for Sustainable Homes: Certificates

Dwelling Emission Rate DER (Maximum 15 credits)% Improvement of DER over TER 2005

Credits Mandatory Levels

≥10% 1 Level 1

≥14% 2

≥18% 3 Level 2

≥22% 4

≥25% 5 Level 3

≥31% 6

≥37% 7

≥44% 8 Level 4

≥52% 9

≥60% 10

≥69% 11

≥79% 12

≥89% 13

≥100% 14 Level 5

True Zero Carbon 15 Level 6

Credits gained for different improvements

25

0

1000

2000

3000

4000

5000

6000

7000

8000

Asconstructed

current SAPreference

Code 1 Code 2 Code 3 Code 4 Code 5 Code 6

CO

2 em

issi

on

s (k

g)


Implications of Code on Carbon Dioxide Emissions

Code 5: Zero Carbon House for Heating/Hot Water and LightingCode 6: Zero Carbon House overall but in reality is this achievable?

-10% -18% -25% -44%

26

27

Improvements on the SAP 2005 standards as required by the different code levels can be met by:

• Improved Fabric performance• Lower U-values

• Technical Solutions• Solar Thermal• Solar Photo-voltaic• Heat Pumps• Biomass• Micro- CHP• Low Energy Lighting (SAP 2005 already specifies 30%)

Responding to the Challenge:

• Energy Service Companies may offer a solution for financing

• Issues of Carbon Trading

SEDBUK DataBase (Seasonal Efficiency of Domestic Boilers in UK)

28

WEB PAGE: www.sedbuk.com/index.htm

29

The Future: Code for Sustainable Buildings

All non-dwellings must display a certificate such as shown

• >10000m2 from 6th April 2008• > 2500m2 from 1st July 2008•All non-residential buildings > 1000m2 from 1st October 2008. •Separate assessments for air-conditioning plant will be phased in from 1st January 2009

Elizabeth Fry Building:

Initially Penalised because it does not have thermostatically controlled radiator values . Does not get credit for triple/ quadruple glazing – analysis system cannot cope!!!!!

There are no radiators!!!!!!

n.k. tovey ( 杜伟贤 ) m.a, phd, ceng, mice, cenv Н.К.Тови М.А., д-р...

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