Measurement and Simulation of Startup and Shut Down of Heat Pumps

The reduction in heating capacity due to on/off cycling of a heat pump can lead to a performance reduction of 530%. In order to get a better understanding of the important parameters to improve the performance of heat pumps, a physics based model is being developed and validated with according measurements. Aim of the model is to achieve a stable and accurate solver with only few empirical tuning parameters. While most “dynamic” models in the literature are actually steady state models calculated for different operating conditions throughout the year, the aim of this project is to characterize the unsteady behavior during the first minutes of runtime and shutdown. Start-up and shut down measurements of brine and air source heat pumps are presented, as well as a preliminary model for the simulation routines.