Performance ratings of concentric and lateral (taped, brazed and extruded) capillary tube suction line heat exchangers running with isobutane

Abstract

This paper is aimed at studying the thermal performance of counterflow capillary tube suction line heat exchangers (CTSLHX) commonly used in household refrigerating appliances. Conventional and novel CTSLHX configurations, with different capillary tube and suction line geometries and made of different materials, were evaluated by means of a purpose-built testing facility designed to provide a strict control of the thermodynamic conditions of the refrigerant at the CTSLHX inlet ports. In total, 220 tests were performed with isobutane under typical operating conditions of household applications. The results pointed out that the extruded lateral configuration presented the highest thermal performance in terms of temperature effectiveness, followed by the lateral-brazed, the concentric, and the lateral-taped, respectively. Furthermore, it was also observed that the thermal performance of the latter is more affected by the tape tightness than that by its thermal conductivity.