Development and implementation of a reversible variable speed heat pump model for model predictive control strategies

Abstract

Flexibility in the energy demand of buildings equipped with Heat Pumps (HPs) may be a solution for the congestion and instability problems of the electrical energy system. However, this flexibility potential is difficult to quantify due to the lack of Variable Speed Heat Pump (VSHP) models in building simulation programs. The purpose of the present work is to present the development of an air-to-water reversible VSHP model in TRNSYS and its application in an energy flexibility scenario of Economic Model Predictive Control (EMPC) in a residential building. A simple but effective combination of TRNSYS Types is used to reproduce the behaviour of a VSHP, while its part load performance is modelled from manufacturer data. When compared with a fixed capacity HP, results showed that in the thermostatic control of the developed model both energy and monetary savings are achievable. These positive effects are even higher when the operation of the HP is managed by the EMPC, reaching a reduction of cost of 50% while maintaining the comfort of the occupants.