A Review of Refrigerant Maldistribution

Abstract

In recent years, conservation of energy has become a challenging issue in air-conditioning applications. In order to overcome this issue, many researchers have recommended the use of a Parallel Flow Condenser and a low Global Warming Potential and Ozone Depletion Potential refrigerant, such as R32, in air conditioning systems. However, PFC faces the critical challenge of flow maldistribution in the tubes. This literature review mainly examines the refrigerant maldistribution problem which has been investigated by previous researchers. It was found that many of the researchers did not properly analyse the influence of flow maldistribution profiles on the performance degradation of heat exchangers. In order to have a comprehensive analysis of tube-side maldistribution in Parallel Flow microchannel heat exchangers, it is recommended that the influence of the higher statistical moments of the probability density function of the flow maldistribution profiles on performance degradation be quantified. Additionally, R32 maldistribution should be analysed and compared with R410A, which is the current commonly used refrigerant in air conditioning units. Moreover, in order to have a realistic simulation of the effect of refrigerant flow maldistribution profiles on performance degradation of heat exchangers, the effect of superheat and sub-cooling must be analysed.

Analysis on the refrigerant (R32) flow maldistribution of microchannel heat exchanger under superheat and sub-cool

“…This paper presents the continuation of the work by Chin and Raghavan [2]. Previous paper studied the impact of the moments of probability density function of air flow maldistribution on the heat transfer performance of a fin tube heat exchanger [3]. It was recommended that mean, standard deviation, and skew should be optimized in the effort of improving the thermal performance of the heat exchanger.…”

Performance and exergetic investigation of a domestic sp

“…Globally, R22 is used as a refrigerant in most air conditioning systems for its suitable properties such as stability, non-toxicity, non-flammability [1][2][3][4] and good thermodynamic properties [5]. The general cause of ozone layer depletion is that Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs) which are a large class of chlorine containing chemicals, migrate to the stratosphere where they react with the ozone [6].…”

“…The losses in the cycle need to be evaluated considering individual thermodynamic processes that make up the cycle. The most commonly used term for evaluating the performance of a vapour compression cycle is the coefficient of performance (COP), which is related to the first law of thermodynamics [3,12]. However, the first law of thermodynamics fails to distinguish between heat and work.…”