Comparison Study of Isceon 49 (A Drop-in Replacement for R12) with R12 and R134a

Due to the undesirable environmental consequences ofR12, there is a great challenge to find a suitable substitute for Rl2. A new refrigerant blend Rl34a!R218/R600a (88'Yoi9'Yol 3%) called JSCEON 49 has been developed as a long term, zero ozone depletion-potential replacement for Rl2. A computer program was written to calculate the cycle characteristics, such as cooling capacity, coefficient of pe1jormance (COP), pressure ratio, system pressure and temperature, and compressor power for design and part-load pe1jormance which is also our base of comparison. A series of tests has been completed to validate the computer program and to study the behaviour of JSCEON 49. Experimental results indicate that the pe1jormance of a system does not degraded on using JSCEON 49, relative to that obtained with Rl2. The results of the computer program shows that Rl2 may be replaced by the new blend without a significant loss in overall performance. NOMENCLATURE p = Density (kg I m 3 ) 77 voi = Volumetric efficiency % a= Heat transfer coefficient (kW I m ° C) Q =Rate of heat transfer (kW) U =Overall heat transfer coefficient (kW I m o C) e = Heat exchanger effectiveness Subscripts c = Condenser e = Evaporator f =Refrigerant cc = Coolant in the condenser ce =Coolant in the evaporator cool = Coolant Vs = Compressor displacement ( cm ) N =Compressor speed (RPM) h = Enthalpy ( kJ I kg) m =mass flow rate (kg Is) T = Temperature ( ° C) A =Area (m ) ci = Condenser inlet co = Condenser outlet ei = Evaporator inlet eo =Evaporator outlet INTRODUCTION At the present time the preferred replacement refrigerant for R12 is HFC RI34a. This has thermophysical properties that compare well with those of R12 and more importantly it has zero ozone depletion potential. However, R134a is not a 'drop-in' replacement for R12 because there is a need to change the compressor lubricant and expansion valve. Changing over from R12 to R134a can therefore be an ex-pensive and time consuming procedure.