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@Vol.26CNo.3@—vŽ|
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Developing an Injection Type Two-Stage Rotary Compressor for CO2 Heat Pump
Tetsuhide YokoyamaEKei SasakiEShin SekiyaEToshihide KodaEHideaki Maeyama
@Conventional heat pump systems have the problem of significant decrease in performance under lower ambient temperature conditions. CO2 refrigerant has a disadvantage in its high leakage rate as compressed gas. This paper describes a two-stage rotary compressor with refrigerant injection for the CO2 heat pump was developed to solve these problems. The performance characteristics and advantages of the two-stage compressor were clarified in comparison with a single-rotary compressor by experimental analysis results. Unique characteristics of the two-stage rotary compressor, such as intermediate pressure pulsation loss, were examined by measuring indicated powers and analyzing compressor losses. The loss was reduced to improve compressor efficiency by increasing the volume of its intermediate connecter. The two-stage rotary compressor was superior to the single rotary compressor with respect to compressor efficiency in the condition of low rotational speed
or high pressure ratio because of the advantage of preventing compressed gas from leaking. Furthermore, wet vapor refrigerant injection improved compressor efficiency of the two-stage rotary compressor, in addition to decreasing the discharge temperature.
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Key words : Compressor, Two-stage rotary, Heat pump, CO2 Refrigerant, Injection, Efficiency, Saving of energy
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