CPD Programme
Figure 3 Comparison heating methods and operating costs
specifically for the domestic housing market.
0.070
They are emerging as a primary low-carbon
0.060 replacement technology in this market – as
a
t
i
n
g
(
£
)
0.050
a stand-alone solution or in combination
0.040
with other technologies. Figure 5 shows
o
f
h
e
0.030
how the housing peak heat load has reduced
e
r
k
W
0.020
significantly since the 1970s, such that a four-
bedroom detached house today has a lower
0.010
C
o
s
t
p
heat loss than a two- bedroom flat in 1970.
0.000
Gas Boiler Direct LPG Boiler Oil Boiler Heat pump Heat pump
A new ASHP recently marketed towards
with an Electric with an with an
Mitsubishi Electric Europe BV. All rights reserved.
with a COP with a COP domestic housing has the refrigerant
efficiency of efficiency efficiency of efficiency
3.0 3.6
2007
0.93 0.99 0.91 of 0.86
circuit completely sealed, very similar to the
Suppliers fuel prices in the above running cost graph are These will only improve, both
domestic fridge and freezer. The unit includes
correct as 24th August 2008 covering postal area LU5 actually and relatively. © copyright
a plate heat exchanger for the heat sink, or
condenser, heating water that is piped to the
Figure 4 Comparison of heating methods: carbon emissions heating application, e.g. radiators, underfloor
heating or hot water cylinder. The unit also
0.50 Fuel CO2 levels per KW
a
t
includes a four-way reversing valve, enabling
0.45
Oil 0.26
LPG 0.25
Gas 0.19
a cooling mode in the summer. The advantages
h
o
f
h
e
0.40 Electricity 0.43
of the sealed refrigerant circuit are improved
0.35
l
k
W
reliability, installation by plumbers without
0.30 specialist refrigerant qualification, and easy
0.25
replacement into the existing water system.
2
p
e
r
u
s
e
f
u
0.20
0.15
Case study
0.10
A retrofit of a four-bedroom house in
K
g
o
f
C
O
Mitsubishi Electric Europe BV. All rights reserved.
Toddington, built in 2000, saw the house fitted
0.05
Gas Boiler Direct LPG Boiler Oil Boiler Heat pump Heat pump
2007
with a non-condensing boiler rated at 23kW,
with an Electric with an with an with a COP with a COP
supplying radiators with water at 70°C and with
efficiency of efficiency efficiency of efficiency 3.0 3.6
0.93 0.99 0.91 of 0.86
Will achieve Code Level 3 – CsSH
an output of 8.4kW. The hot water demand
© copyright
was 140 litres per day. The boiler was replaced
Figure 5 Progressive domestic housing: peak heat loads with an ASHP based on a house heat loss of
8kW at an ambient temperature of minus 3
25
degrees C. Some radiators were upgraded and
)
W
20
were supplied with water at 55 degrees C to
provide heating at 8.4kW. The average COP
h
15
over the 2007/8 winter was 3.5. The savings,
14kW compared to the gas boiler, were 48 per cent
e
a
t
L
o
a
d
(
k
10
less CO
2
emissions and a 38 per cent reduction
8.5kW
in running costs.
P
e
a
k
H
5
5kW
© Terry Welch
0
Mitsubishi Electric Europe BV. All rights reserved.
1970s 1980s 1990s 2000s 2006 2016 2007
References
CIBSE Journal March 2009 CPD, Refrigeration
– inside the box, Terry Welch
2 Bed Flat 3 Bed Semi 4 Bed Detached
© copyright
BSJ 2008 CPD Supplement, Heat pumps with
radiators, Terry Welch
The heat delivery methods divide into either radiator will have to be increased to give BSJ July 2008 CPD, Gas absorption heat pumps,
heated water or heated air. Either of these can the same heat output with the lower water Tim Dwyer
be supplied at medium temperatures (say 35 temperature. BSJ April 2006 CPD, Packaged air to water heat
degrees C to 45 degrees C) for space heating Technology constantly improves, however. pumps, Tim Dwyer
requirements such as heater batteries or Figure 3 shows that, with a COP
h
between 3.0 BSJ January 2006 CPD, Ground source heat
underfloor heating, or at high temperature and 3.6, heat pumps outperform all other types pumps, Graeme Maidment
for domestic hot water heating or for process of heating shown and can be included in low- Heat Pump Association Newsletter, Mar 2009, Two
drying. The highest temperatures that can carbon heating solutions, along with biomass, moves forward, Tony Bowen.
www.heatpumps.org.uk
normally be achieved with vapour compression CHP and solar thermal. Figure 4 also shows Claiming Enhanced Capital Allowance, Energy
cycle heat pumps is 60 degrees C to 65 that heat pumps have lower CO
2
emissions Technology List, managed by Carbon Trust, on
degrees C, but most applications would suggest 55 than other forms of heating. behalf of Defra.
www.eca.gov.uk/etl
degrees C as the economic maximum. When These figures are based on air source MitsubishiElectric Heating Systems, Ecodan
used for heating with radiators, the size of heat pumps (ASHPs), which are marketed presentation, Max Halliwell
www.cibsejournal.com May 2009 CIBSE Journal 61
CIBSEmay09 pp59-62 cpd.indd 61 4/30/09 5:54:53 PM
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72