EVALUATION OF THE BENEFITS IN HEAT PUMP DESIGN WHEN USING A DYNAMIC LUMPED-PARAMETER MODEL

A heat pump dedicated to building heating (e.g., of the air-to-water type) is subject to variations in the cold source temperature, in the load demand or even in capacity when performance is aimed at. Such changes influence the internal behaviour of the heat pump and a ad hoc control can be achieved provided that a dynamic model describing the mass and heat balances is used. Here the authors introduce a dynamic, lumped-parameter model based on moving-boundary exchanger sub-models, static compressor and expansion valve sub-models. The interests of the model for heat pump sizing or for the design of the superheating control are shown. Moreover, a refined version of the model is presented here as the de-superheating region of the condenser is described separately, instead of being merged into the condensation region. The benefits of this enhancement are evaluated with respect to the superheating control. Validation through experience will take place in a future but high-priority development step.