Sustainable Building Operation Using Simulation - Low Energy Cooling for Sustainable Buildings - page 213

Figure 6.12 Influence of collector mass flow on solar fraction for variable generator inlet temperature
systems can again be used (see Figure 6.12). The collector surface area required to
cover 80% of the demand is now reduced to 31m 2 , that is only 2m 2 kW − 1 . The cold
water temperatures were still at 12 ◦ C/6 ◦ C and a wet cooling tower was used (Case 2).
If the cold is distributed using chilled ceilings or thermally activated concrete slabs,
the temperature levels can be raised and performance improves (Case 3). For cold
water temperatures of 21 ◦ C/15 ◦ C the required collector surface area is only 27m 2 ,
that is 1.8m 2 kW − 1 (see Figure 6.13).
Figure 6.13 Required collector area per kilowatt of cooling power to achieve 80% solar fraction for
different generator and evaporator inlet temperatures applied to the office, Case 1