Performance Evaluation and Optimization of A Refrigerant Distributor for Air Conditioner

Abstract

Refrigerant mal-distribution in a distributor located at the inlet of a heat exchanger used for an air conditioning system plays an important role in the heat exchanger performance. Distribution performance in the distributor is greatly affected by the flow conditions as well as the geometrical parameters of the distributor. To clarify the distribution characteristics, it is essential to know flow rates of both liquid and vapor states at every branch tube after distribution. This paper proposes a relatively simple test method, which enables to measure the inlet quality and the flow rate of refrigerant at every branch of the distributor. By using the proposed evaluation method, optimization on the geometrical parameters of the distributor was conducted to reduce the refrigerant mal-distribution. It was confirmed that the optimized distributor was able to reduce the mal-distribution of the refrigerant over branches despite the flow condition changes. By the flow visualization of the refrigerant in the distributor, it was observed that certain amount of liquid refrigerant remained and swayed unstably at the bottom of the distributor. It is supposed that the liquid refrigerant behavior in the distributor great affects the distribution performance.

Maldistribution in air–water heat pump evaporators. Part 1: Effects on evaporator, heat pump and system level

“…Based on practical experience and the values reported by Bach et al (2012a) and Yoshioka et al (2008), it is assumed that no stronger maldistribution will occur in a reasonably designed and maintained heat pump unit. Worse effects may occur during long-term operation, e.g.…”

“…A quantitative study of gas/liquid phase non-uniformity in a distributor was performed by Yoshioka et al (2008). A maximum deviation of 30% between distributor inlet quality and quality at a single distributor outlet was observed at an installation angle of 10 relative to vertical.…”

Maldistribution in air–water heat pump evaporators. Part 2: Economic analysis of counteracting technologies

“…Based on previously reported values (Bach et al, 2012;Yoshioka et al, 2008) i n t e r n a t i o n a l j o u r n a l o f r e f r i g e r a t i o n 5 0 ( 2 0 1 5 ) 2 1 7 e2 2 6 assumed that the considered maldistribution cases represent somewhat realistic scenarios. However, both hot water production and frost and defrost is neglected in this study.…”

Study of refrigerant flow consistency and tolerance control of a distributor for air conditioner

“…Some other scholars proposed another method to optimize the performance of refrigerant distribution by ensuring the inlet quality or the flow rate at the branch tube of the dsitributor are stable [14,16]. The research from Yoshioka et al [16] evident that the distribution for the refrigerant is significantly influenced by the change of the refrigerant flow coditions. Hence, an optimization on the geometrical parameters of the distributor was proposed to ensure the distribution remains stable over the various operating range.…”