It is found that for the working conditions
mentioned above, the ejector improves the maximum COP by
18.6% as compared to internal heat exchanger system and 22%
as compared to the conventional system. As Yari and
Sirousazar (2008) proposed a new refrigeration cycle with an
ejector, internal heat exchanger and intercooler, it was found
that the COP and second law efficiency values of the new
ejector-compression cycle were on average 8.6 and 8.15 per
cent higher than that of the conventional vapor compression
refrigeration with R125. Lee et al. (2005, 2006) found that the
optimal condensing temperature of a cascade-condenser is
18 C at a condensing temperature of 35 C and an evaporating
temperature of 50 C. However, they indicated only
one specific condition and did not evaluate the effects of
changing the design conditions, such as the condensing and
evaporating temperature on the optimal condensing temperature
of the cascade condenser and its corresponding
maximum COP. Although lots of efforts have been dedicated
to improve the cascade's function, there is a real gap in the
ejector utilization for both circuits of the cascade cycle
through these studies.