Experimental Performance Investigation and Variable Speed Compressor Implementation of a Household Refrigerator

Abstract

The objective of this thesis is to investigate the performance of a household refrigerator in steady state operating conditions and reveal the effect of variable speed compressor implementation on the system performance. This work is based on experimental studies which include energy consumption (EC) tests in accordance with ISO 15502 standard and implementation of a variable speed compressor (VSC) to a household refrigerator. To accomplish these works, the household test refrigerator is instrumented with various sensors and a comprehensive test program is prepared for data acquisition, analysis, and control of the VSC. During the EC tests, the refrigeration cycle performance is tracked simultaneously by real time analyses of each refrigeration cycle component which include calculations of heat transfer from each component, mass flow rate of the refrigerant, and work inlet to the compressor. In this study, three tests of refrigerators utilizing single speed compressor (SSC) with different condenser lengths, and one test of the refrigerator with a VSC are conducted in an air chamber in which the ambient temperature is kept at 25oC and the relative humidity is under 75%. The VSC is controlled by temperature feedbacks of air stream from the freezer and the fresh-food compartments to maintain the required temperatures in those compartments.