WEST LAFAYETTE, IN — Hydrocarbons (HCs) may not make much of an impact in the United States — then again, they just may. Nevertheless, it’s safe to say that they are gaining more and more attention most everywhere else as a refrigerant.

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, Refrigeration

Specific 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 reduction of refrigerant charge of more than 65% compared to the charge of R-22.
  • The capacity in heating as well as cooling mode is expected to be similar compared to the R-22 commercial heat pump.
  • An increase higher than 10% in COP at central test conditions in both heating and cooling mode is predicted.
  • 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