A zero ODP replacement for R12 in a centrifugal compressor: an experimental study using R134a

Abstract

SUMMARYIt is well believed that the hydrofluorocarbons (HFCs) and their mixtures are the most promising candidates to substitute the conventional refrigerants, chlorofluorocarbons (CFCs) and HCFCs which contain chlorine atoms in the molecule. This substitution is necessary for the harmful action of CFCs and of HCFCs toward atmospheric ozone layer damage because the disruption of ozone has been attributed to chlorine. For this reason they must be replaced by more environment-friendly refrigerants, as the new family, designated as HFCs, that are chlorine free. Centrifugal compressors differ from positive displacement compressors in two major respects: high vapour volume flow for a given physical size and lower pressure ratio. They are particularly suited to applications where differences between evaporator and condenser temperatures are low. The preferred properties for fluids used in centrifugal compressors differ in certain important aspects from those preferred for fluids used in positive displacement units. In particular centrifugal compressors typically utilize fluids such as CFC114, CFC113, CFC12 and CFC11 for which many potential candidate replacements exist; however, for CFC12, HFC134a is the most suitable replacement. A comparison of the refrigerants HFC134a and CFC12 has been carried out and the results from the tests, using data from a refrigerating plant operating with a centrifugal compressor are reported. The chilled water cooling plant, with a refrigerating capacity of 6500 kW is made up of a centrifugal twostage compressor, a condenser linked to a cooling tower, an economizer and a flooded evaporator. Experimental results show that a lower coefficient of performance is found when R134a is used as substitute for R12; the difference between the COP values decreases rising the compression ratio.

Performance Prediction of Centrifugal Compressor Based on Performance Test, Similarity Conversion and CFD Simulation

“…In the industry field, the kinds of the centrifugal compressor's working substance are increasing more and more, such as hydrogen [1],oxygen [2], carbon dioxide [3], R134a [4][5][6], and mixture of several gases [7]. How to obtain the performance of the centrifugal compressor economically and accurately is attractive for researchers [8,9] when the working substance is real gas.…”

“…The performance test of centrifugal compressor was carried on in [12,13] as R134a is applied. But the test is very expensive.…”

Performance assessment of heat pumps using HFC125/HCs mixtures

“…Park et al [10] investigated the performance of a domestic water purifier using R430A (a near azeotropic TECHNICAL NOTE mixture composed of HFC152a and HC600a in the ratio of 76/24, by mass) as an alternative to HFC134a. Aprea [15] examined the performance of HFC134a as replacement for CFC12 in a centrifugal compressor, and an interesting result was obtained, i.e. Dalkilic et al [11] compared the performance of CFC12, HCFC22, HFC134a and HCF134a, HFC152a, HFC32, HC290, HC1270, HC600, HC600a mixtures, and their theoretical results showed that the HC290/HC600a, HC290/ HC1270, HC290/HFC152a (60/40 by mass), HFC32/ HFC134a (30/70 by mass) have a slightly lower performance coefficient than CFC12, HCFC22 and HFC134a for the condensation temperature of 501C and evaporation temperature ranging from À301C to 101C.…”

“…They found that HC290 is similar in characteristics to HCFC22, and HFC410A can achieve both increased performance and decreased product size and result in a more competition heat pump, but a comparable GWP. Aprea [15] examined the performance of HFC134a as replacement for CFC12 in a centrifugal compressor, and an interesting result was obtained, i.e. the difference in the COP reduces from 10 to 5% if the refrigeration compressor ratio increases.…”