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Performance Characteristics of Water-Chilling Heat Pump Using CO2 on Control of Inverter Frequency

인버터 주파수 제어에 따른 CO2용 수냉식 열펌프의 성능 특성

  • Son, Chang-Hyo (Division of Refrigeration and Air-Conditioning, Pukyong National University)
  • 손창효 (부경대학교 냉동공조공학과)
  • Received : 2010.11.15
  • Accepted : 2010.12.17
  • Published : 2010.12.31

Abstract

The performance characteristics of water-chilling heat pump using CO2 for the control of inverter frequency was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter flow type heat exchangers with concentric dual tubes, which are made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2.4m length. The experimental results summarize as the following: for constant inlet temperature of evaporator and gas cooler, as mass flow rate, compression ratio and discharge pressure increases with the inverter frequency. And heating capacity and compressor work increases, but coefficient of performance(COP) decreases with the inverter frequency of compressor. As inlet temperature of secondary fluid in the evaporator increases from $15^{\circ}C$ to $25^{\circ}C$, compression ratio and compressor work decreases, but mass flow rate, heating capacity and COP increases with the inverter frequency of compressor. The above tendency is similar with performance variation with respect to the variation of inverter frequency in the conventional vapor compression refrigeration cycle.

Keywords

Carbon dioxide;Design of heat pump;Inverter frequency;Performance characteristics;Transcritical cycle

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