Civil Engineering Reference
In-Depth Information
drive strategy ensuring the balance between PV production and electricity con-
sumption of the residence. The thermal energy balance is kept in equilibrium by the
additional boiler that balances the ST production, the CHP unit production and the
speci
c thermal energy consumption of residence.
In order to increase the performance indicators of the CCHP system, especially
its ef
ciency, the PV electricity production is correlated to the energy consumption
eliminating the excess production for the month with the biggest PV production and
electricity consumption, respectively (in this month e
PV
=e
sys
). Similarly to the
mechanical compression chiller, the utilization factor of PV panel area is recalcu-
lated and the similar procedure is used for the utilization factor of the thermal panel.
The calculation result shows k
PV
¼
136 and k
ST
¼
062 (see Tables
6
and
36
).
The calculation result (Table
37
) allows the graphic representation of the elec-
tricity balance shown in Fig.
41
and the thermal balance shown in Fig.
42
.
The monthly heat balance has a small excess. After the calculation of the heat
and electricity from solar energy, it is necessary to verify the conditions set about
architectural sustainability and utilization factors. For this case the results show a
utilization factor of 19.8 % (less than 40 %).
The performance indicators obtained indicate a reduction of the PES = 64 % and
a signi
0
:
0
:
cant increase of the CCHP system
'
s global ef
ciency EFF = 84.6 %. The
monthly distribution of PES is given by Fig.
43
.
Table 37 Performance improving for structural model type off-grid
Month
Energy specific
consumption of the
mCCHP system
Specific power and
heat production of the
PV and ST panels
Specific power and
heat production of
the CHP unit
Specific heat
production of
the boiler
e
sys
(kWh/m
2
)
q
sys
(kWh/m
2
)
e
PV
(kWh/m
2
)
q
TP
(kWh/m
2
)
e
cg
(kWh/m
2
)
q
cg
(kWh/m
2
)
q
ad
(kWh/m
2
)
January
3.33
15.94
0.74
1.59
2.59
7.76
6.59
February
3.33
13.77
1.06
2.26
2.27
6.82
4.69
March
3.33
10.94
1.74
3.72
1.59
4.77
2.45
April
3.33
6.76
2.42
5.17
0.91
2.74
0.00
May
3.33
5.56
3.01
6.42
0.32
0.97
0.00
June
3.33
6.08
3.27
7.00
0.06
0.17
0.00
July
3.33
7.09
3.32
7.09
0.01
0.03
0.00
August
3.33
7.09
2.91
6.22
0.42
1.26
0.00
September
3.33
5.16
2.15
4.59
1.18
3.54
0.00
October
3.33
6.79
1.50
3.21
1.83
5.48
0.00
November
3.33
10.63
0.80
1.72
2.53
7.58
1.33
December
3.33
14.21
1.50
1.29
1.83
5.50
7.42
Total
40
110
24.42
50.29
15.54
46.63
22.49
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