| Abstract: | Experimental results are presented which demonstrate the effect of lubricating oil on the COP and evaporator performance of refrigeration and heat pump systems. These are compared with the predictions of a simple theoretical analysis and it is shown that the agreement is satisfactory. It is demonstrated that evaporator heat extraction can be degraded by as much as 50 per cent and the COP by up to 30 per cent when compared to the performance indicated by the properties of pure refrigerants for systems containing up to 15 per cent oil. An interesting phenomenon is also demonstrated, wherein there is a clearly identifiable optimum setting for the evaporator superheat control, and the way in which this varies with oil concentration is indicated. |
