Active Thermal Cooling Technologies - Low Energy Cooling for Sustainable Buildings - page 169

Figure 5.57 Heat recovery factors for plate and coaxial solution heat exchangers as a function of the
weak solution inlet temperature

were within an acceptable range of 76% and 92%. Figure 5.57 shows a comparison
of the different heat recovery factors measured for different SHX weak solution inlet
temperatures.
Due to the low solution mass flow rates, the coaxial SHX had a better heat exchange
than the plate heat exchanger and the tubular heat exchanger of prototype 1 which was
also too heavy. A series of test runs were carried out following the above changes and
the analysis showed an improved COP of 0.2 to 0.3 and continuous evaporator cooling
performance of 0.5 to 1.5 kW (see Figure 5.58); this was achieved when it was run at
an operating pressure of 20 10 5 Pa, a cooling water inlet to the absorber of 20 ◦ C, ×

0.50 9.0

0.45

8.0

0.40

7.0

0.35

Heating power 6.0

0.30

COP

5.0

0.25

4.0

0.20

3.0

0.15

Cooling power

2.0

0.10

1.0

0.05

0.00 0.0

135 140 145 150 155 160 165 170 175 180 185

Generator heating inlet temperature / °C

Figure 5.58 COP and heating and cooling power ranges as a function of generator temperature for the
second prototype