Alternate refrigerants for vapour compressor system
Heating, ventilating, air conditioning and refrigeration
industries are searching for ways to increase performance, durability of
equipments and energy efficiency in a sustainable way while reducing the cost
of manufacturing. With the present refrigerants, environmental problems such as
ozone layer depletion, global warming potential, green house gases and carbon
emission are increasing day by day.
In response, the refrigeration industry has
developed two alternative refrigerants; one based on Hydro chloro Fluorocarbon
(HCFC),
and another based on Hydro Fluorocarbon (HFC). The HCFCs have a 3 to 10% ozone depleting potential as compared to CFCs and also, they have an atmospheric lifetime between 2 to 24 years as compared to 100 or more years for CFCs (Brandt, 1992). However, even HCFCs Hydro chloro Fluorocarbon are mandated to be phased out by 2005, and only the chlorine free (zero ozone depletion) HFCs would be acceptable.
and another based on Hydro Fluorocarbon (HFC). The HCFCs have a 3 to 10% ozone depleting potential as compared to CFCs and also, they have an atmospheric lifetime between 2 to 24 years as compared to 100 or more years for CFCs (Brandt, 1992). However, even HCFCs Hydro chloro Fluorocarbon are mandated to be phased out by 2005, and only the chlorine free (zero ozone depletion) HFCs would be acceptable.
Some of the alternative refrigerants’ coefficients of
performance values are found to be higher than their base traditional pure
refrigerants. The effects of the main parameters of performance analysis such
as refrigerant type, degree of sub cooling, and superheating on the performance
coefficient, refrigerant charge rate and volumetric refrigeration capacity are
investigated for various operating conditions as case studies.
A theoretical
performance study on a traditional vapour-compression refrigeration system with
refrigerant mixtures based on HFC Hydro Fluorocarbon (134a, 32, 152a, 290) was done for various
ratios and their results are compared with CFC (12, 22) and HFC HFC Hydro Fluorocarbon 134a as possible
alternative replacements. The use of HFCs and HCFCs results in slightly lower
efficiencies as compared to CFCs, but this may change with increasing efforts
being made to replace CFCs.
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