Refrigeration system performance using liquid-suction heat exchangers

Heat transfer devices are provided in many refrigeration systems to exchang e energy between the cool gaseous refrigerant leaving the evaporator and wa rm liquid refrigerant exiting the condenser. These liquid-suction or suctio n-line heat exchangers can, in some cases, yield improved system performanc e while in other cases they degrade system performance. Although previous r esearchers have investigated performance of liquid-suction heat exchangers, this study can be distinguished from the previous studies in three ways. F irst, this paper identifies a new dimensionless group to correlate performa nce impacts attributable to liquid-suction heat exchangers. Second, the pap er extends previous analyses to include new refrigerants. Third, the analys is includes the impact of pressure drops through the liquid-suction heat ex changer on system performance. It is shown that reliance on simplified anal ysis techniques can lead to inaccurate conclusions regarding the impact of liquid-suction heat exchangers on refrigeration system performance. From de tailed analyses, it can be concluded that liquid-suction heat exchangers th at have a minimal pressure loss on the low pressure side are useful for sys tems using R507A, R134a, R12, R404A, R290, R407C, R600, and R410A. The liqu id-suction heat exchanger is detrimental to system performance in systems u sing R22, R32, and R717. (C) 2000 Elsevier Science Ltd and IIR. All rights reserved.