• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.358-363
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• 2007

In this study, experimental study on the heating performance of a $CO_2$ heat pump with gas injection was performed varying gas injection ratio and outdoor temperature to improve the heating performance of $CO_2$ heat pump. The twin rotary compressor having volume ratio of 0.7 was adopted in the $CO_2$ heat pump. From the test results, the heating capacity and COP were increased and the compressor discharge temperature was decreased with the increase of injection ratio. At the outdoor temperature of $-8^{\circ}C$, the heating capacity and COP with the injection were increased by 45% and 24%, respectively, compared with non-injection condition.