Effect of common faults on the performance of different types of vapor compression systems

Abstract

The effect of faults on the cooling capacity, coefficient of performance, and sensible heat ratio, was analyzed and compared for five split and rooftop systems, which use different types of expansion devices, compressors and refrigerants. The study applied multivariable polynomial and normalized performance models, which were developed for the studied systems for both fault-free and faulty conditions based on measurements obtained in a laboratory under controlled conditions. The analysis indicated differences in responses and trends between the studied systems, which underscores the challenge to devise a universal FDD algorithm for all vapor compression systems and the difficulty to develop a methodology for rating the performance of different FDD algorithms.

Effect of the distribution of faults and operating conditions on AFDD performance evaluations

“…The protocols are currently used commercial and public AFDD tools. In general, AFDD tools detect and diagnose faults by comparison of measurements with expected values, which typically come from analytical redundancy, such as models, or from heuristic rules [15][16][17]. Common input variables for unitary air-conditioners include suction superheat, liquid-line subcooling, and air-side temperature change across the evaporator or condenser, but there is a wide variety of AFDD approaches that use other inputs in addition to these [18].…”

An experimental study of the behavior of a model variable refrigerant flow system with common faults

“…The research on the performance of the air-conditioning system by faults began in the 1990s. As of now, most of the research focuses on the experimental study of the single or double fault types of the air-conditioning system, and most of the research system objects are split system [5][6][7][8][9], rooftop unit [8,10,11], residential heat pump [12][13][14][15]. Refrigeration charge fault and heat exchanger fouling are the most concerned single fault type by research.…”

Study on Performance and Environmental Impact of Supermarket Refrigeration System in Japan

“…Although the compressor is hermetically sealed, a significant amount of leakage (about 20%) can occur from joints and seals, mechanical failure or during servicing 12,13) . This leakage will lead to performance degradation and will increase energy consumption 14,15) . Moreover, the leaked refrigerants have high GWP (Table 1) which will eventually contribute directly to the global warming 16) .…”