Simulation based assessment on representativeness of a new performance rating procedure for cold climate air source heat pumps

Abstract

Cold climate air-to-air heat pumps (CCHP) offer a strong potential for energy use reductions in Canadian homes. Proper selection of the unit is critical in order to take advantage of the improved efficiency and increased heat capacity at low ambient temperatures and ability to modulate to meet a wide range of heating loads. A new performance rating procedure (CSA EXP07) was developed to better represent the seasonal energy efficiency of CCHP systems versus current test procedures that do not always accurately characterize the response to dynamic loads in a colder climate zones, thus resulting in inaccurate equipment rating. To validate the representativeness of the new performance rating procedure and quantify the potential over-or underestimation of energy savings using current performance rating procedures, a CCHP data-driven model is developed and simulated in a code-compliant single-detached Canadian home for different climate regions: Marine, Cold-Humid, Cold-Dry, Very-Cold and Subarctic. These energy models then serve as the basis for comparing the seasonal heating coefficient of performance of a CCHP system, which can be compared to the current and newly proposed performance rating procedure.