WIDE-BOILING REFRIGERANT MIXTURES FOR ENERGY-SAVING

Power saving can be achieved in air conditioning/heat pump systems by using a refrigerant mixture whose temperature glide in the condenser and evaporator approximately matches the temperature intervals through which air is heated and cooled. The challenges are in the choice of mixture, the designs of the condenser and evaporator, and the control system. Solutions to all these problems are advanced and these are tested in a laboratory rig running on an R22/R142b mixture. A range of results is presented showing power savings as high as 25% compared with a conventional R22 system. This experience is incorporated in a computer model by which the performance of a similar system running on a wide range of environmentally acceptable mixtures is tested. Predictions are reported for a range of mixtures, from binary to quaternary, showing how units can be designed with a 25% power saving for an additional first cost of the same order.