Investigation of the Potential of Air-Source and Hybrid-Source Heat Pumps in Cold Climates

Abstract

This study investigates the performance of air and hybrid-source heat pumps, particularly in cold climates where freezing can compromise efficiency. The problem statements to solve during the research are investigating the air-sourced Heat Pump Evaporator cooling load areas of cold weather based on the daily ambient conditions and optimizing the defrosting thermal load required to assist the hybrid heat pump based on dewpoint temperature, relative humidity, and humidity ratio. Preventing frost accumulation on the evaporator is crucial, as it can degrade the coefficient of performance (COP). A novel mathematical and thermodynamic model was implemented and tested using Engineering Equation Solver (EES) under specific initial and boundary conditions. Subsequently, the model was applied to a 1-ton heat pump using R-410A as a working fluid, combining air and assisted source. This hybrid approach allows for a comprehensive analysis of the system's performance under challenging weather, focusing on avoiding freezing. The results showed that the air-source heat pump (ASHP) had an annual energy consumption of 3,564 kWh, whereas the hybrid-source heat pump (HSHP) consumed 2272 kWh with an annual defrosting thermal load of 961 kWh. Integrating an electrical coil in the hybrid system led to a 9.3% reduction in annual energy consumption compared to conventional defrosting methods, significantly enhancing Heat Pump system performance in cold climates.