Engineering, 19.08.2020 18:01 brownvester44

A refrigeration plant operates in Pretoria on refrigerant R134a at an evaporator pressure of 105kPa (gauge) and a condensing pressure of 920 kPa (gauge). There is a sub-cooling of 3K with a superheat of the gas entering the compressor of 8K. The compressor is a four-cylinder reciprocating compressor with a bore of 67mm and a stroke of 57mm with an estimated capacity of 35kW. The compressor is directly coupled to an electric motor running at 1470rev/min and a power consumption of 19,5 kW. Calculate: 1. The clearance volume efficiency if the compressor clearance is 3,6% 2. The actual volumetric efficiency 3. The compression efficiency when the mechanical efficiency is 85% and the motor efficiency 90%.

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A refrigeration plant operates in Pretoria on refrigerant R134a at an evaporator pressure of 105kPa...