Transcript Domestic hot water consumption trends in the years 1999…2004

CHANGES IN THERMAL ENERGY
CONSUMPTION IN APARTMENT
BUILDINGS OF ESTONIA
Teet-Andrus Kõiv,
The biggest part of energy in Estonian housing
sector is consumed by apartment buildings .
These buildings have mostly one-pipe heating
systems and central domestic hot water systems
with towel driers on circulating pipe. About 65%
of our apartment buildings are heated from
district heating network.
Part of the buildings are heated from local boiler
houses, where gas is the most common fuel.
The approximate U-values of the nonrenovated envelope elements of typical
apartment buildings are:
W/(m2K)
External walls
- 1.0 – 1.2
Roof-ceilings
- 0.8 – 1.0
Windows
- 2.8 – 3.0
Recommended U-values for envelope
elements of new apartment buildings:
External walls
Roofs
Windows
W/(m2K)
- 0.28
- 0.22
- 2.1
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In the 70s of the last century, total heat energy
consumption in apartment buildings in Estonia
was relatively high, about 350 kWh/m2 per year
(per total apartment area).
The domestic hot water energy consumption
was about 145 kWh/m2 per year
(95 l/d per person) – the domestic hot water rate
in apartment building energy consumption was
41%.
Trends in heat energy consumption in the
years 1999…2004
2
kWh/m year
250,0
200,0
150,0
100,0
50,0
0,0
1999
2000
2001
2002
2003
2004
The average heat energy consumption in apartment buildings decreased from 219
kWh/m2 per year in 1999, to 206 kWh/m2 in 2004, the decrease being only 6%.
Special heat energy consumption for domestic hot water heating in apartment
buildings decreased from 56 to 41 kWh/m2 per year, the decrease constituted 27%.
Domestic hot water consumption trends in the
years 1999…2004
70
l/person per day.
60
50
40
30
20
10
0
1999
2000
2001
2002
2003
2004
Hot water consumption decreased from 60 l/d per person in 1999, to
44 l/d per person, in 2004 .
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Domestic hot water consumption rate in typical
apartment buildings in 1974 was 95 liters per
day per person. This is 2.2 times more than in
2004.
Domestic hot water consumption in the US
residential homes is 46-85 l/d per person
In apartment buildings in Russia it is about 85
l/per day per person.
In Finland it is about 70 l/per day per person.
Domestic cold water consumption trends
in the years 1999…2004.
140
l/person per day.
120
100
80
60
40
20
0
1999
2000
2001
2002
2003
2004
The total water consumption decreased from 129 l/d per person in 1999 to 98 l/d
per person in 2004
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The total water consumption in Tallinn in 2004
was 98 l/d per person. These data are close to
water consumption in the housing sector of
Belgium in 1998 and that of the Czech Republic
and Bulgaria in 2001. Compared with that of
Finland, our consumption is approximately 1.5
times less.
The share of domestic hot water in total water
consumption is 46% and has remained
approximately the same in the last 6 years
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Great changes in thermal energy and domestic hot
water consumption have occurred during the last 30
years.
Thermal energy consumption has decreased more
than 40% - from 350 kWh/m2 per year (in 1974) to
206 kWh/m2 in 2004.
Considerable changes have taken place in domestic
hot water consumption, falling from 6.6 l/d per m2 (in
1974) to 2.0 l/d per m2 in 2004. As to thermal
energy consumption the respective fall was from
144 to 41 kWh/m2 per year in 2004, i.e. 3.3 times.
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The main reasons for a decrease in domestic
hot water consumption in Tallinn apartment
buildings in recent years are:
consumption metering in apartments;
already high and still rising prices of water and
heat;
extensive renovation of domestic hot water
systems, including circulation renovation;
use of modern equipment (taps, showers).
For energy saving in apartment buildings
is essential:
 analyses of consumption
 renovation of envelope elements
 renovation of heating system:
- hydronic balancing
- control of heat output on the level of heating
coils
 renovation of windows and
 renovation of ventilation
Heat requirements of apartment buildings for heating
(per gross apartment area)
30
25
kWh/m
2
20
15
10
5
0
September
October
November December
January
February
Heat requirements by simple degree-day method
March
April
May
Simulated heat requirements
The average difference between the apartment building heat requirements determined by
simulation and by calculation on the basis of simple degree-days was 10% for the whole heating
period
The average difference between the apartment
building heat requirements determined by simulation
and by calculation on the basis of simple degreedays was 10% for the whole heating period, the
greatest difference 28%, occurring in May. This is
due to the greatest solar radiation in May as
compared to other months of the heating period. For
spring and autumn months heat energy
consumption calculations by simple degree-days
method are not exact.
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The simulation of heat requirements for a typical
apartment building before and after the renovation
of construction elements was carried out. The effect
of external walls and roof insulation, windows
renovation and rising control efficiency on heat
requirements by simulation has been analyzed.
The energy saving potential of old typical apartment
buildings by renovation of envelope elements, rising
control efficiency and renovation of equipment in
Estonian conditions accounts for about 40-45%.
For example in full renovated 72 apartment building
thermal energy saving was about 43%.
The results of the analysis of heat losses of different envelope elements,
natural ventilation and water heating in typical non-renovated apartment
buildings
Ventilation
18 %
Water heating
20 %
Windows
22 %
ZZ ZZZ
External walls
25 %
Floor 5 %
Roof 10 %
Special energy consumption
in office buildings, schools and apartment buildings
Left: Heat energy; right: heat energy and electricity per closed net area
for office building,schools and apartment buildings
CONCLUSIONS
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During the past 15…20 years, there have been
great changes in energy and water consumption
in the Estonian housing sector.
Thermal energy consumption has decreased by
about 40%.
The decrease in domestic hot water
consumption in the last 30 years per gross area
was more than 3 times.
Continued:
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The main reasons for a decrease in energy consumption
of Estonian apartment buildings have been the following:
high prices of water and heat and their continued
increase;
water consumption metering in apartments;
extensive renovation of domestic hot water systems,
including circulation renovation;
use of modern equipment (taps, showers);
renovation of heat substations;
balancing of heating systems;
partial renovation of envelope elements.
Continued:
The energy saving potential of typical old
apartment buildings by renovation of envelope
elements, improved control efficiency and
renovation of equipment in Estonian conditions
accounts for about
40-50%.
Thank you!