Paper Conference

Proceedings of eSim 2020: 11th Conference of IBPSA-Canada


Energy performance advantages of using multiple compressors in a heat pump operating in heating mode

Geoffrey Viviescas, Houaida Saidi, Michel Bernier, Michael Kummert
Polytechnique Montréal, Canada

Abstract: The energy performance of a multi-compressor geothermal heat pump (MC-GHP) is investigated in this study. The MCGHP is equipped with eight compressors of different capacities and efficiencies. In operation, the compressor having the lowest energy consumption (compressor power + auxiliary heating) at a given time step is selected. The objective is to determine, through simulations over three winter months, the difference in the Seasonal Coefficient of Performance (SCOP) of the MC-GHP compared to a regular single compressor geothermal heat pump. In the first part of the paper, a complete steady-state model of a water-to-water MC-GHP is developed. Heat transfer is modelled from first principles in the evaporator and condenser plate heat exchangers. Detailed manufacturer performance maps based on the AHRI 540-2015 standard are used to model the performance of the compressors. Performance degradation caused by heat pump cycling is handled using a part-load-factor approach. Results show that the SCOP of the MC-GHP is 13.3% higher that the SCOP obtained with a single compressor geothermal heat pump.