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Abstract
The ozone layer gives the earth a good protection against the sun ultra-violet rays. Some refrigerants like R12 have bad ozone depletion potential, so it is necessary to employ new refrigerants that protect the ozone layer. The R22/R142b mixture with 60 % R22 by mass concentration is suggested as a replacing refrigerant for R12
The present work is devoted to study the heat transfer process at boiling of R22/R142b mixture with 60% R22 by mass concentration as a replacing refrigerant for R12 for enhanced surfaces. To reach this aim an experimental test rig was designed and constructed at the Astrakhan State Technical University in Russia.
Experiments are carried out for smooth ,finned , porous coated ,and with partially closed volume edge (pcv) tubes the heat flux ranged from 1000 W/m2 to 10000 W/m² at +10 OC, -10 OC And -20 OC boiling temperatures
The study showed that the heat transfer coefficient at boiling of R22/R142b mixture for porous coated tubes surfaces is more than that for smooth one.