air conditioning refrigerant r134a has value of global warming potential (gwp) 1300, which is much higher than mac directive (gwp below 150) passed in july 2006. this prompted a search for alternative refrigerant with gwp value less than 150. r1234yf is a new refrigerant which has lower gwp value of 4. effect of blower speed has been compared and flammability issue of r1234yf has been addressed...

h = heat transfer coefficient q = heat flux from the wall of evaporator to refrigerant Tw =Temperature at the wall of evaporator Tf = Temperature of the refrigerant kal = Conductivity of aluminum t = Thickness of evaporator M& = Mass flow rate of refrigerant Cp = Constant-pressure specific heat of refrigerant Tsat = Saturation temperature of refrigerant Tin = Temperature of refrigerant at inlet...

This paper presents the experimental research into the evaluation of lubricity for polyolester (POE) lubricant with HFC-134a refrigerant in rotary and reciprocating compressors for household refrigerators. In order to evaluate the lubricity for POE lubricant with HFC-134a refrigerant, we conducted 4-balls wear tests in the mixing environment of POE lubricant and HFC-134a refrigerant. In the pre...

A household refrigerator designed to work with R-134a was used as an investigation unit to assess the prospect of using mixed refrigerants. The recital of the refrigerator using mixed refrigerant was investigated and compared with the performance of refrigerator when R-134a was used as refrigerant. The effect of condenser temperature and evaporator temperature on COP, refrigerating effect was i...

A heat pump system requires proper refrigerant charge amount. Once refrigerant is charged into a heat pump system, its charge amount is fixed. For this reason, prediction of optimal refrigerant charge amount is very important in order to yield best performance. Too low charge amount degrades capacity of heat pump. On the other hand, excessive charge amount decreases coefficient of performance (...

This research is aimed to define , (1) the effects of refrigerant to the environment, (2) derive the eco friendly refrigerants by using software REFPROP, (3) describe the properties of refrigerant by mixing them in appropriate percentage, (4) reducing GWP and ODP by providing suitable substitute of CFC’s and HCFC’s refrigerants, (5) reducing the effect of refrigerant to the ODP. This analysis i...

four kinds of refrigerant mixtures R22/Rl34a, R22/Rl52a, R22/Rl42b and R22/Rl23, which contain some new halocarbons which are considered to be the alternatives for CFCs, were evaluated in order to realize higher condensing temperature than that using R22 at high temperature operation, and larger heating capacity than that using R22/Rll4 at normal temperature operation. These mixtures were appli...

The given paper is aimed at constructing the general circuit of heat processes in a semihermetic reciprocating refrigerant compressor as a basis of application of new ecology-friendly refrigerants as well as optimizing design parameters of compressor. While performing this work the following problems were solved: 1. Experimental research of heat processes in a semihermetic refrigerant reciproca...

This paper presents the heat transfer coefficients and the pressure drop measured during HC-600a (Isobutane) condensation inside a brazed plate heat exchanger: the effects of saturation temperature, refrigerant mass flux and vapour super-heating are investigated. The heat transfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant mass flux. At low...

The refrigerant release technology relieves even eliminates the over-compression loss of scroll compressor by bypassing the refrigerant in the compression chamber to the suction pipe under small system pressure ratio conditions. Because the room air conditioner works in mild conditions at most of the time, its seasonal energy performance is expected to be effectively improved by the refrigerant...