Fig. 10 shows the variation of the coefficient of
performance with the heat sink temperature for superheating
at the compressor inlet ranging between 4 and 8 8C for the
different heat source temperatures of 8, 12 and 16 8C. It can
be found that as the heat source temperature increases, the
COP also increases for both modes of operation. The heat
transfer rate in the evaporator of the TPERC is higher than
that of the CRC. This causes the COP of the TPERC to be
higher than that of the CRC over the whole range of
experimental conditions. However, the graph demonstrates
that the decreasing rate of COP in the TPERC is greater than
that of the CRC as the heat sink temperature increases. In
other words, the improvement in COP diminishes as the heat
sink temperature increases. This is mainly because of the
increment of the mass flow rate in the motive nozzle,
causing a higher power input. The COP of the TPERC
becomes increasingly higher compared to that of the CRC as
the temperature of the heat sink temperature decreases. This
shows the advantage of part-load conditions resulting from a
lower ambient temperature, which is frequently encountered
in real life situation.