Sustainable Building Operation Using Simulation - Low Energy Cooling for Sustainable Buildings - page 224

Table 6.5 Summary of design values for the office with variable control strategy (Case 2). Offices 1
and 2 are located in Madrid, office 3 in Stuttgart

Case Cooling Chiller Collector Storage Solar Average

load file power/ area/ volume/ yield/ COP

kW m 2 m 3 kWh m − 2 -

1 Office 1 15 31 2 644 0.67

2 Office 2 15 54 5 784 0.67

3 Office 3 15 25 2 324 0.64

For very low operating hours such as the office building in the Stuttgart climate
with only 313 full load hours, the costs are between D 640 and 700 per MWh, 60% of
which are due to the chiller investment costs alone (see Figure 6.26).
The calculated solar thermal system costs were between D 85 and 258 per MWh for
solar cooling applications, depending on the operating hours and the location. They
go down as far as D 76 per MWh for the office in Madrid with high internal loads
and a high-temperature cooling distribution system. These costs are getting close to
economic operation compared with fossil fuel heating supply. The main dimensioning
results for the buildings with a good control strategy and a low-temperature fan coil
distribution system (Case 2) are summarized in Tables 6.5 and 6.6.
The total costs per megawatt hour of cold produced by the thermal chillers are given
in Table 6.7.
If the system integration and mounting costs are assumed to be 45% of total in-
vestment costs instead of 17%, the costs per megawatt hour of cold are in the range

Table 6.6 Summary of energy performance data

Case Cooling Collector Collector Storage Solar

energy surface surface volume thermal

demand/ per MWh/ per kW/ per surface/ efficiency/

MWh m 2 MWh − 1 m 2 kW − 1 m 3 m − 2 %

1 13.7 2.2 2.0 0.07 37

2 29.8 1.8 3.6 0.09 45

3 4.7 5.5 1.7 0.08 26

Table 6.7 Costs for solar thermal cooling systems

Case Solar Total Chiller cost Solar cost Total cost

investment/ D investment/ D C chiller / D C solar / D C total / D

per MWh cold per MWh heat per MWh cold

1 14260 32490 130 101 268

2 22400 40630 60 85 183

3 12140 30370 378 258 676