Feasibility study and in-depth performance assessment of needle valve using as expansion device in refrigeration system

Abstract

The needle valve (NEV) has high potential for further using as the automatic expansion device in the refrigeration system. However, the experimental proof is required for further developing the automatic controller for operation. This paper proposes the feasibility study and performance map of the needle valve (NEV) using as the expansion device in a small vapour compression refrigerator (VCR). The relevant parameters produced by NEV are compared with those using capillary tube (CT) and thermostatic expansion valve (TEV) which are the conventional device. The system COP, superheated degree at evaporator outlet (SHDevap-out), subcooled degree at condenser outlet (SCDcon-out), mass flow rate, volumetric refrigeation capacity, compressor's specific work and refrigerant quality are considered for comparisons. Additionally, the economic assessment of using NEV compared with the other two devices is proposed. It is found that COP produced by NEV are similar to TEV which is better than CT. The ecomnomic assessment indicates that the NEV produces similar useful cooling energy per unit cost to that using TEV which is higher than CT. Overall results indicate that the NEV can efficiently be used as the expansion device in VCR which is alternative to the conventional expansion devices.