Studying the impact factors influencing variable-capacity heat pump energy performance through simulation

CanmetENERGY/Natural Resources Canada, Varennes, QC, Canada

Abstract

Cold-climate variable-capacity air-to-air heat pumps (VCHPs) have the potential to significantly reduce energy use in the Canadian residential sector. However, optimizing their integration in the Canadian climate can be a challenge, with efficiency and operating behaviour heavily dependent on ambient conditions, building thermal loads, modulating capability and the units’ individual performance characteristics. Better understanding how these factors influence energy performance can lead to improved system selection, and ensure that high efficiency space heating systems contribute towards meeting Canada’s emission reduction targets. This study outlines three major factors – individual performance characteristics (cold climate capacity, part load performance), modulation ratio and sizing – related to VCHP selection, and examines their relative impact on annual energy use and operating behaviour using a simulation-based approach.