Fig. 6 shows the variation of the average evaporator
pressure with heat source temperature for superheating at
the compressor inlet ranging between 4 and 8 8C for
different heat sink temperatures of 27, 32, and 37 8C. Fig.
6 also compares the average evaporator pressure obtained
from the TPERC with that obtained from the CRC. The
graph shows that the TPERC has a higher evaporator
pressure than the CRC. The flooding refrigerant in the
evaporator in the TPERC is the subcooled and two-phase
mixture, while that in CRC is the two-phase mixture and
superheated vapour. This results in the higher heat transfer
rate in TPERC causing the average evaporator pressure to be
higher than that in the CRC. This means that the
corresponding evaporator temperature of the TPERC is
also higher than that of the CRC, resulting in a small
temperature difference between the refrigerant and the heat
transfer fluid (water). This is desirable from a thermodynamic
point of view in that the system should be run at as high
an evaporator pressure as possible in order to obtain the
highest possible COP.