Kornhauser [1] analyzed the thermodynamic performance
of the ejector expansion refrigeration cycle. He found a
theoretical COP improvement of up to 21% over the
standard cycle under standard conditions, 215 and 30 8C
for evaporator and condensor temperatures, respectively.
This result is based on ideal cycle components and constant
mixing pressure in the ejector, using R-12 as a refrigerant.
Harrell et al. [2] tested a two-phase ejector and used its
performance obtained from the test rig to estimate the COP of
the refrigeration cycle. It was found that the COP improvement
ranged from 3.9 to 7.6% with R-134a as a refrigerant.
Menegay et al. [3] developed a bubbly flow tube to reduce the
thermodynamic non-equilibrium in the motive nozzle. This
device was installed upstream of the motive nozzle. An
ejector using the bubbly flow tube improved up to 3.8% of the
COP over the conventional cycle under standard conditions
with R-12 as the refrigerant. However, this result is not as
good as was expected. Therefore, study of the ejector
expansion refrigeration cycle should be extended. Domanski
[4] found that the theoretical COP of the ejector expansion
refrigeration cycle was very sensitive to the ejector
efficiency. Nakagawa et al. [5] showed that the longer the
length of the divergent part of the motive nozzle, the higher
the motive nozzle efficiency could be achieved. This was
likely caused because the longer divergent part provided a
longer period of time for the two-phase flow to achieve
equilibrium.
Kornhauser [1] analyzed the thermodynamic performanceof the ejector expansion refrigeration cycle. He found atheoretical COP improvement of up to 21% over thestandard cycle under standard conditions, 215 and 30 8Cfor evaporator and condensor temperatures, respectively.This result is based on ideal cycle components and constantmixing pressure in the ejector, using R-12 as a refrigerant.Harrell et al. [2] tested a two-phase ejector and used itsperformance obtained from the test rig to estimate the COP ofthe refrigeration cycle. It was found that the COP improvementranged from 3.9 to 7.6% with R-134a as a refrigerant.Menegay et al. [3] developed a bubbly flow tube to reduce thethermodynamic non-equilibrium in the motive nozzle. Thisdevice was installed upstream of the motive nozzle. Anejector using the bubbly flow tube improved up to 3.8% of theCOP over the conventional cycle under standard conditionswith R-12 as the refrigerant. However, this result is not asgood as was expected. Therefore, study of the ejectorexpansion refrigeration cycle should be extended. Domanski[4] found that the theoretical COP of the ejector expansionrefrigeration cycle was very sensitive to the ejectorefficiency. Nakagawa et al. [5] showed that the longer thelength of the divergent part of the motive nozzle, the higherthe motive nozzle efficiency could be achieved. This waslikely caused because the longer divergent part provided alonger period of time for the two-phase flow to achieveequilibrium.
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