Improved Performance of Transcritical R744 Gas Coolers For Efficient Heat Pumps in the Northeastern US Winter Markets Available to Purchase

The main goal of our effort is to analyze, design, develop prototype and test electrical air source heat pumps (ASHPs) for hot water, space heating and cooling for multi-family buildings. Focusing on implementing the use of low Global Warming Potential refrigerants (e.g. TR-CO₂) system to provide a cleaner and more sustainable alternative to society’s heating and cooling needs. This specific research is focused on the heating mode. A key challenge of TR-CO₂ systems is the heat rejection which occurs in the gas cooler as a single gas phase. Identification of the pinch point is essential to avoid occurring within the gas cooler; leading to increases in efficiency.

We present here system performance of a TR-CO₂ air source heat pump system using a customized python computer model coupled to commercial software for whole building analysis. This coupling enables variable heating load conditions for a mid-size multi-family building in New York City. The heat pump system is being modeled using proprietary code for the heat pump system coupled to EnergyPlus™ software with different gas cooler variations for constant and then variable loads. The TR-CO₂ system is benchmarked against R410A with very optimistic results.