engleski

Comparative effects of two injection paths on performance of a heat pump with a sub-cooler injection configuration

As one of the most promising and convenient heating service to replace coal-fired boilers and electricheaters due to its high energy efficiency, a heat pump has received more and more attention for theeconomical application and extensive research. The injection technology can be used to improve the heatpump performance. Currently, the injection ratio and pressure ratio are usually used to characterize theeffects of injection styles on its performance. This is not conducive to its practical operation control becauseof additional cost increase. In this work, the effects of two injection cycles due to two injection pathswere characterized with openings of a sub-cooling electronic expansion valve, comparatively tested andanalyzed. Test results demonstrate that the heating capacities (Qh), electricity power (EP) and coefficient ofperformance with the refrigerant injection into compressor (CRI) are more than those with the injection intoaccumulator (ARI), and the overall effect with the CRI is positive because the Qhimprovement outperformsEP increase. For example, the maximum Qhwith the CRI at 55, 60 and 85 rps were 8.1%, 7.7% and18.3% higher than those without the CRI, and 7.3%, 6.7% and 19.0% higher than those with the ARI. Thethermodynamic model was used to analyze the experimental results and expound the mechanism of theinfluence of injection path on the performance of heat pump. This work provides guidance for improvingenergy efficiency in common areas and enhancing Qhin cold areas.

heat pump ; injection cycle ; injection path ; COP ; sub-cooler

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