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The latest wave of overseas research is experimentation in pulling CFC, HCFC, and HFC refrigerants out of a variety of systems and seeing what happens when HCs are used instead.
“While HCs do not always offer the higher COP [coefficient of performance] for the four categories considered, over half of the cases showed a mean improvement of up to 10%. An appreciable proportion of the cases showed an improvement of between 10% to 20%,” according to data gathered by Calor Gas, Ltd. and University College, London. “Overall, approximately 90% of the cases did reveal better performance.”
The report did note the focus was on HCs vs. CFCs and HCFCs, rather than HFCs. A caution flag went up over use of butane/ propane blends in domestic refrigerators, propane in air conditioners, and isobutane in heat pumps.
Looking at specific hydrocarbons relative to R-22, it was noted that hydrocarbon R-1270 and a proprietary blend of R-170/R-290 “offer favorable reductions in approach temperature differences, both evaporator and condenser, [and] benefits in terms of pressure loss and compressor COP.”
Heat Pump, RefrigerationSpecific heat pump work was reported on by scientists from Italy, Spain, Sweden, and Switzerland.
A medium-size air-to-water heat pump was converted from R-22 for use with propane (R-290). Among the findings:
A technology institute in Brazil wanted to compare HC-600a and HFC-134a in commercial freezers. Testing was done on an ice cream cabinet. “An experimental investigation has indicated the technical feasibility of using HC-600a based on improved performance,” according to conclusions. Reduced energy consumption and lower internal air temperature were noted with 600a. The project has now gone from lab research to field-testing.
Scientists from the University of Jordan took a 2.5-ton split system air conditioner and replaced its R-22 with butane and propane in different ratios.
The report noted, “All investigated hydrocarbon mixtures can be used as possible alternative refrigerants to R-22 with COP values that are competitive with R-22 values.”
It was further noted that “The 100% propane mixture had the highest COP values among all the hydrocarbons tested. The 90% propane mixture is selected to be the most suitable alternative refrigerant to R-22 based on both higher COP and equal saturated pressure match.”
Finally, the report contended that such changes could be done “with no modifications or adjustments to [units] designed for R-22. No problems have been encountered with the compressor. No degradation of lubricating oil could be detected after the refrigerator worked for 1,000 hours using the same oil.”
Publication date: 10/02/2000