Page 231 - Low Temperature Energy Systems with Applications of Renewable Energy

218 Low-Temperature Energy Systems with Applications of Renewable Energy

Fig. 5.37 The dependence h ex ¼ f(T env ) and s ¼ f(T env ) on the ambient air temperature for the
HPU system shown in Fig. 5.36.

Fig. 5.38 Exergy losses in the HPU elements versus the ambient air temperature showing the
effect of different seasons on the exergy losses. EM1 and EM2 are the electric motors that drive
CM1 and CM2 compressors, respectively.

The formula for calculating the loss of exergy for the condenser has the following
form:

s
E _ COND ¼ _ m C ðh 5 h 6 T env ðs 5 s 6 ÞÞ Q _ HPU c (5.29)
Dk
where Q _ HPU is thermal capacity of the HPU; s s is the exergy temperature Carnot
function of a heat receiver.