The performance of a high temperature heat pump unit for heat recovery is experimentally evaluated. The unit consists of a twin-screw refrigeration compressor
a condenser
an evaporator and oil cooler.The effect of the oil cooling on performance of the heat pump unit is theoretically analyzed. The effect of the oil injection temperature on performance is also evaluated. The discharge temperature linearly changes with the temperature of oil injection. Results show that the unit enables tostably get an outlet water with temperature 85 ℃ and works in a wide range of high temperature conditions with high coefficient of performance
and the keys to improving the high temperature heat pump unit often lie on the selection of oil cooling temperature and oil quantity.The best oil cooling temperature should be controlled between 45 ℃ and 65 ℃ when the condensing temperature is above 70 ℃
and the oil cooling can increase the heat capacity of the heat pump by 6.3%.
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references
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