Design and Construction of a Vapour Compression Refrigeration System as Test Rig to Investigate the Performance of Liquefied Petroleum Gas (LPG) as Refrigerant

Abstract

The design and construction of a refrigerator as a test rig, in investigating the performance of Liquefied Petroleum Gas (LPG), which has zero ozone depleting potential and very low global warming potential, as working fluid in vapour compression refrigerating system as a possible alternative. The design was made with these assumptions:(a) steady state operation; (b) no pressure loss through pipelines,; (c) heat losses or heat gains from or to the system are neglected and of 75% isentropic efficiency. The following heat sources are considered: transmission load,qt= (A)(U)(ΔT), infiltration load, qa= ma(ho – hi), product load, qpa= (m)(c)(ΔT), specific heat given off by the product in freezing, qf = mLf,, quantity of heat given off by the product in cooling from its freezing temperature to the final storage temperature, qpb= (m)(c)(ΔT), light Load, qL= Light rating(W) x Time(S). The total cooling load capacity of the refrigerator was obtained summing the various sources of heat into the refrigerated space, qTCL= qt+ qa+ qpa+ qf+ qpb+ qL. The total cooling load (QTCL) in watt is obtained to be 0.27302 kW. Considering 10% of safety factor, = 0.027302 kW approximately =0.300322 kW. This average load is referred to as Required Equipment Capacity (REC), which is used as a basis for component selection. The required equipment capacity obtained was 0.451 kW. The desired running time is 16 hours/day. The joints were properly welded. The major bought out components are: the evaporator, the compressor, the condenser and the expansion device.