Z E M C H 2 0 1 2 I n t e r n a t i o n a l C o n f e r e n c e
630
The effects of each option on the annual energy consumption, operating energy cost and
carbon dioxide (CO
2
) emissions were assessed by making use of SAP 2009 (Table 7).
The options that do not concern PV show a drastic increase in domestic energy
requirement as well as annual operating energy cost (Options 1, 2, 5, 8, 11, 14 & 17) as
opposed to options that include PV combined with an MVHR system selected (Options 3,
6, 9, 12, 15 & 18). Moreover, when PV thermal is added to the combination options,
there is further reduction in the energy use which in turn contributes to reducing
operating energy cost (Options 4, 7, 10, 13, 16 & 19).
Table 7: Delivered & Primary energy, Operating energy cost, DER & TER assessment results of 19
alternatives selected
The results indicate that options that include a PV/T system can be considered to be
highly cost-effective when the saving of operating energy cost is highly appreciated.
When PV is completely excluded, energy requirements and associated CO
2
emissions
become relatively high. This tendency could be explained by the constant electricity use
for the operation of an MVHR system. In SAP calculations, CO
2
factor of electricity is
considered to be 0.517
kg CO
2
per kWh while that of mains gas is 0.198 kg CO
2
per
kWh. This clearly shows that the use of electricity leads to 2.6 times more CO
2
emissions
than mains gas. According, in terms of CO
2
emissions, a house equipped with a mains
Combi-
nations
Delivered
Energy
(kWh/year)
Primary
Energy
(kWh/year)
PV
Generated
Electricity
(kWh/year)
(negative
quantity)
PV/T
Generated
Heat
(kWh/year)
(negative
quantity)
Annual
Cost
of
energy
( £)
CO2
Emissions
(kg/year)
Dwelling
Emission
rate
(DER) kg
CO
2/
m2/yr
Target
Emission
rate
(TER) kg
CO
2/
m2/yr
Opt1
9092
10645
0
0 448 2030 11.75 15.09
Opt2
6173
8253
0
0 383 1551
8.97 15.09
Opt3
2968
-1190 -3286
0 12 -160 -0.92 15.09
Opt4
513
-3693 -3286 -3440 -64 -160 -0.92 15.09
Opt5
6362
8861
0
0 408 1658
9.59 15.09
Opt6
3076
-735 -3286
0 31
-81 -0.47 15.09
Opt7
696
-3162 -3286 -3440 -43
-81 -0.47 15.09
Opt8
6455
9202
0
0 421 1718
9.94 15.09
Opt9
3169
-394 -3286
0 45
-21 -0.12 15.09
Opt10
826
-2783 -3286 -3440 -28
-21 -0.12 15.09
Opt11
7243
10727
0
0 477 1995 11.54 15.09
Opt12
3946
1131 -3286
0 101
256
1.48 15.09
Opt13
1198
-1683 -3286 -3440 15
256
1.48 15.09
Opt14
6882
9745
0
0 439 1820
11 15.09
Opt15
3596
149 -3286
0 63
82
0 15.09
Opt16
875
-2626 -3286 -3440 -22 -457
0 15.09
Opt17
6827
9868
0
0 445 1839
11 15.09
Opt18
3541
272 -3286
0 69
101
1 15.09
Opt19
973
-2347 -3286 -3440 -11 -407
1 15.09
SAP ASSESSMENT RESULTS
