ENV-2D02
Energy
Conservation
Jane Powell (JC)
j.c.powell@uea.ac.uk
Building Regulations
What is energy conservation?


Supply and Demand
Supply

More efficient production
• CHP

Changing demand

More appropriate use
• Fuel switching

Use less
•
•
•
•
Demand management
Reduce heat loss
Low energy appliances
Behavioural change
Why is energy conservation important?
2030 (EU)
Based on present trends
90% imported oil






80% imported gas
Climate change
Limits to fossil fuels
Security
Risks
Threat to our current way of life
Fuel poverty
3 million UK households
Observed and simulated change:
Temperature change ºC
natural and man-made factors
1.0
observed
model simulation
0.5
+
0.0
+
-0.5
1850
Source: Hadley Centre
1900
1950
2000
UK targets

Kyoto targets

GHG 12.5% below 1990 levels 2008-2012
• 2002 14.4%; 2003 13.4%; 2004 12.6%

UK CO2 Targets
• Previous target: 20% below 1990 levels by 2010
• New target: 60% below 1990 levels by 2050
• 50% 2010 target can be achieved by energy efficiency measures

Renewables

10% electricity generated by 2010
• 3.5% 2004
Reduce heat loss & behavioural change

Of who?



Occupants
Developers, planners,
architects
What method?



Incentives
• Subsidies
• Economic instruments
Voluntary initiatives
Regulations
The Energy Performance of Buildings Directive (EPBD)
2002/91/EC


40% of final energy consumption in the EC is
in the buildings sector.
Improving energy efficiency, carbon emissions
from buildings could be reduced by 22%.
Objectives of the Directive:

To promote the improvement of the energy performance of buildings
within the EU through cost effective measures;
 To promote the convergence of building standards towards those of
Member States which already have ambitious levels.
Measures include:




Methodology for calculating the energy performance of buildings;
Application of performance standards on new and existing buildings;
Certification schemes for all buildings;
Regular inspection and assessment of boilers/heating and cooling
installations.
Must be implemented by 4 Jan 2006
UK Response
Part L Building Regulations (2005)

Comes into force in England and Wales on 6 April
2006 (Scotland & Ireland to follow)

Office of the Deputy Prime Minister (ODPM)
Complies with EU legislation
Move away from energy conservation to carbon
emission reduction
UK National Calculation Methodology (NCM) for
energy performance of buildings



Deficiencies in earlier Building Regulations

Before 1994 if double glazing was used



From 1995



Could include incidental gains from appliance use/solar gains
If consumption <= standard house - regulations could be relaxed
further
1994 & 2000 regulations



window area could be doubled
requirements for walls/roof/floor could be relaxed
if overall loss < = standard house (type 1 trade off)
If triple glazing used window area can be increased by 50% (type 2
trade off)
If higher insulations for walls used, greater window area permitted
provided <= standard house.
Traditionally framed for minimum compliance rather than actively
promoting energy conservation


Less so by 2000 Regs
2005 Regs tightened further
Comparison of energy consumption for a standard detached
house at various ages and improvements (Heat losses in W0C-1)
800
unimproved
700
25mm
50mm
600
100mm
500
100+CAV
400
100+DG
300
100+DG+CAV
200
150+DG
100
200+TG+CAV
0
250+DG
pre-w ar post-w ar
1960s
1976
1985
1990
1994
2000
de
ta
se
ch
m
ed
i-d
et
ho
ac
he use
d
te
ho
rr
a
us
de
ce
e
t
d
ac
se
h
he
m
ou
i-d
d
b u se
et
ac
ng
he
al
ow
d
bu
ng
bo
al
tto
ow
m
en
d
fl a
to
m
p
id
en t
-s
d
to
fla
re
y
t
bo
en
tto
d
m
ce fla t
nt
re
to
p
c e f lat
nt
re
m
id
fl a
-s
t
to
re
y
c e flat
nt
re
fla
t
Effects of built form on energy consumption (Heat
loss WoC-1)
600
500
400
300
200
100
0
2002
1976
1994 Regulations

Single glazing could no longer be used routinely for domestic
buildings
 Glazed area 22.5% of floor area



Standard Assessment Procedure
(SAP) rating for new buildings






50% greater than 1990 regs
50% potential saving lost
0-100 – higher the better
No target SAP but requirements relaxed if >60
SAP 80-84 – Regs automatically satisfied
Includes energy running costs in calculation
Trade offs permitted
Does not specify ventilation rates but advise on estimating
 Make allowance for solar water heating
 Include hot water requirements
Building Regulations 2000


Current regulations - implemented April 2002
Energy rating method



Requirement of heating & hot water changed to encompass overall
system performance, not just controls





Lower (better) standards (loft insulation)
Reductions in U values (technical limits)
Changed methods for calculating U values
Lower U values for windows



Boiler seasonal efficiency, inspection & commissioning included
New requirements for efficient lighting systems & provision of
information for householders
Standards of fabric insulation improved


SAP replaced by Carbon Index method for compliance
SAP ratings still to be calculated and notified to building control bodies
Based on sealed double-glazed units with low emissivity panes
Area of glazing increased to 25% floor area
Target U-value method retained but provisions for trade-offs
improved.
Compliance procedures 2000 Regulations
Three methods to demonstrate compliance with Building
Regulations:
1.
Elemental approach
2.
Target U-Value method
3.
Carbon Index
1. Elemental approach – meet specific conditions






Heating must be gas, oil, heat pump, CHP DH, biogas or biomass
U-values < BR2000 standards
Area window, doors, roof lights <=25% floor area
Boiler: SEDBUK efficiency >=78% gas, 80% LPG, 85% oil
[SEDBUK – Seasonal efficiency of domestic boilers in the UK. The average
annual efficiency achieved in typical domestic conditions.]
2. Target U-Value method

Calculate Target U-Value


Modify target




a function of areas of floor, roof, walls, windows etc
gas & oil boilers: actual SEDBUK efficiency
standard SEDBUK efficiency
electric & coal heating: divide by 1.15
No modification for heat pumps, biomass, biogas, CHP
Modify target if area south facing windows > area north
facing windows
 Calculate weighted average U-value of all external
surfaces
 Weighted average U-value must be <= Target value
3. Carbon Index Method





Most complex method
Replaces SAP energy rating as a method of
compliance
Carbon index appears to be 0-10
Must be >= 8 to comply
Max carbon index 10 – but actually 17.7!


Reality: 8 out of 17.7 or 4.5 out of 10!
SAP procedure is followed



up to point of introducing costs of fuels
actual annual energy consumption is used to calculate the
annual carbon dioxide emission
translated into a carbon index
Standard Assessment Procedure (2001)

Calculate U-values
 Check U-values are achieved
 Calculate








gross heat requirements (Heat Loss Rate)
hot water requirements
incidental & solar gains
effective gains
effective internal temperature
corrected degree-day parameter
net space heating total energy requirement
Select heating method (pumps, appliance efficiency)
 Calculate Total Energy Requirement
 Estimate energy costs of total space heating, hot water &
pumps
 Deflate energy by Energy Cost Factor – 0.96 1994, 1.05 2001
Carbon Index Calculations (2000 regulations)

Attempts to assess the true environmental performance of a
building
 Follow Standard Assessment Procedure to calculate Total
Energy Requirement
 Calculate CO2 emissions for building
 Calculate Carbon Factor (CF)




CF=CO2 (TFA+45) where TFA is total floor space
Carbon Index (CI) CI=17.7-9.0 log10(CF)
Complication of scale >10
Present regulations (2000) indicate that compliance is 11kg CO2
per m2 – carbon index of 8
 If true scale was used Zicer & Elizabeth Fry would out perform
the theoretical 10 out of 10 building.
SAP
U-values
Total Energy
Requirement
CARBON
Index
C02 emissions
Energy costs
Energy Deflator
1-100
1-120 (SAP 2001)
Carbon Factor
>=8
Carbon emissions for same house designed to
different standards
Variation of Carbon Emission and Carbon Index with
Building Regulations
70
pre-war
60
1955
1965
50
2
kg CO2/m /yr
Theorectical
Perfection
in 2002
Regulations
40
1976
30
1985
1990
1994
20
2002
10
Elizabeth Fry
ZICER
0
0
1
2
3
4
5
6
Carbon Index
7
8
9
10
Variation of Carbon Emission and Carbon Index
problems with current Building Regulations
20
18
The ore cti cal
Pe rfe cti on
i n 2002
Re gul ati ons
16
2002
12
2
kg CO2/m /yr
14
10
8
6
El i z abe th Fry
ZIC ER
4
2
0
7
8
9
Carbon Index
10
Critique of the Standard Assessment Procedure (SAP)

Energy efficiency index – but gives a rating that is monetary based
not energy based

Assumes a general heating level in house – no variation
Hot water requirements based on floor area formula not occupancy
Incidental gains based on floor area not occupancy



Standing charge ignored for electricity, included for gas. Oil doesn’t
have a fixed charge (1994 & 2000)


Energy Cost Deflator



Unnecessary complication that allows for inflation
1994 Regs – possible SAP rating of over 110


Lower efficiency oil heating can give a higher SAP rating than more
efficient gas
SAP of 100 achievable
2000 Regs – widen scale (over 120) to keep houses at similar value
Better to have max of 100 for zero energy house
Effective changes in SAP rating with specific
changes (1994 regulations)
SAP changes by:
Change U-values by 10%
2–3
Change window area by 10%
1–2
Change floor area by 10%
4–5
Change heating from mains gas to
LPG (little change in energy
consumption)
- 15
Change heating from condensing
gas to inferior oil
+5-10 !!!!!
Source: Monahan, J (2002) MSc Dissertation UEA;
Turner, C. (2003) BSc Dissertation UEA
2006!!!
Draft 2005 Building Regulations



Comes into force 6th April 2006
Will use SAP 2005
Technical changes







Changes in how U values are calculated
Thermal bridging – weighted average to be considered, not
just design
Pressure testing of buildings for developments over a
specific size
U-values windows – include frames
Information on lighting use
Estimates of overheating in summer included
Shading issues relating to solar gain must be addressed
Draft 2005 Building Regulations: Compliance
Greatest change is how compliance is achieved - five
criteria:

Dwelling Emission Rate (DER)


Gives considerable latitude in design
Limits on design flexibility


limits trade-offs
Limit effects of solar overheating

South facing windows, ventilation
Quality of construction – evidence of actual performance




Quality of workmanship
Pressure testing of large buildings & developments
Providing information


Maintenance and operation of the building
(Home Information Pack)
Dwelling Emission Rate (DER)

Is equal to CO2 emissions per unit floor area
for space and water heating and lighting less
emissions saved by energy generation
New dwellings & extensions

Non Dwellings & large dwellings >450m2


Building Emission Rate
SAP
U-values
Total Energy
Requirement
CARBON
Index
C02 emissions
Energy costs
Energy Deflator
1-100
1-120 (SAP 2001)
Target
Emission
Rate
C02/m2
Carbon Factor
>=8
Dwelling
Emission Rate
DER<TER
UK National Calculation Methodology (NCM) for
energy performance of buildings

Compliance with the 2006 amendments to Part L of the Building
Regulations in England and Wales (similar for Scotland and N.
Ireland)
 Dwellings: NCM new version of the existing Standard
Assessment Procedure (SAP)
 Non domestic buildings: Simplified Building Energy Model
(SBEM)





prototype www.ncm.bre.co.uk
user interface called iSBEM.
Purpose: to produce consistent and reliable evaluations of energy
use in non-domestic buildings (and some domestic buildings)
for building performance certification purposes (eventually)
(Home information packs - 1 June 2007)
SAP 2005 Regulations



Basic methods similar to previous regulations
Calculations more complicated
Takes into consideration





window frames
solar gain
energy for lighting
effect of thermal bridges
energy generated by micro CHP, photovoltaics, etc

Problems with monetary values remain

Recalibration of scale


SAP 2005 rating is related to the energy cost factor (ECF) by:



A house with a previous SAP rating will be reduced
If ECF>=3.5, SAP 2005 = 111-110*log10(ECF)(1)
If ECF<3.5, SAP 2005 = 110-13.96*ECF (2)
SAP rating scale (1-100) - SAP100 is achieved at zero ECF

Can be >100 if house is net exporter of energy
Summary Table of U-values for different
Building Regulations
1976
1985
1990
U – Values
External Wall
Roof
Floor
Windows
1.0
0.6
1.0
0.6
0.35
0.6
0.45
0.25
0.45
not
specified
not
specified
not
specified
Windows as % of
external walls
equivalent
to 17%
12
-
Windows as % of
total floor areas
-
-
15
1994
-2 o
Wm
2000
2005
-1
C
SAP
< 60
SAP >
60
0.45
0.2
0.35
3.0
0.35
0.16
0.25
2.0*
0.45
0.25
0.45
3.3
0.35
0.16
0.25
2.0
22.5
25
22.5
25%
English housing tenure by SAP rating, 2001
ODPM (2003)
Effects of Building Regulations Part L

2002, 2005 & 2008 amendments should
increase efficiency of new build and
extensions by 25%

…but will it?
What are the barriers to using building
regulations to reduce energy use and
carbon emissions
?

UK residential sector accounts for 30% total
UK energy demand

1990 – 2003



Since 1970



Total UK energy demand increased 7.3%
Residential energy increased 17.5%
Energy use per household changed little
Overall energy use for residential sector increased
by 32%
At household level


Reduction in heat loss – energy saving
Increases in energy demand – lights & appliances
Population & households

UK population



current aprox 60 million
2050 62.5 – 72 million
Age structure



2003 – 76.2 men, 80.6 women
2031 – 81.0 men, 84.9 women
Total population over 65
• 2002 10.9 m, 2031 12.7 m, 2060s 17 m

Household size


1961 3.01; 2004 2.33
One person households: 1971 18%, 2002 29%
Effects of household size on energy use
Fawcett et al (2000)
Construction & demolition





Building regulations are for
new houses & extensions
In UK very low levels of
construction & demolition
2002/3 167,000 housing starts
1996 – 2004 nearly 160,000
dwellings demolished –
20,000/year
If we continued at this rate the
average house will last 1000
years!
Future of household energy
supply lies in the hands of:





Central government
400 local authorities
25 million households
Appliance and fuel supply industries
Construction building services




Fragmented
Multiple suppliers of specialist products
Huge number of sub contractors
Costs saved by:
• reducing capital costs
• standard components
• standard practices
Whole life costs/life-cycle costs

typical costs for owning a building are in the ratio of :



1 for construction costs
5 for maintenance costs
200 for building operating costs
Source: Royal Academy of Engineering
Life cycle cost (LCC)

LCC = Capital Cost
+ Present worth of Maintenance and Energy Cost
- Present worth of Salvage value

Capital cost


initial capital expense for equipment
the system design, engineering, and installation.

Maintenance: operation and maintenance costs/year
Energy cost: yearly fuel cost.
Salvage value: net value in the final year

http://wcm.nu/LCC/lcc_calculation.html


Thank you