Evaluation of Dynamic Operation Effects for a Heat Pump in a Solar Combi-Plus System

摘要

Real-like –dynamic- working conditions shall be taken into account in the assessment of the seasonal performance of thermal system, particularly when these are driven by renewable energy sources. A vapour compression reversible heat pump installed in a solar combi-plus system was studied to verify the influence of variable sources and loads on the overall performance. The machine was tested in laboratory, following a dynamic sequence, which reproduces the seasonal real-like boundary conditions. The results of the dynamic test highlight the non-negligible influence of dynamic working conditions on the seasonal performance of the heat pump. Two unfavourable factors were identified, i.e. the presence of many on-off cycles during cooling mode and fast variations of the boundary condition – i.e. changing of set points in switching the operation from space heating to domestic hot water preparation. Given the importance of correctly evaluating these aspects, a short dynamic test procedure was developed and validated. This allows the evaluation of the seasonal performance of the heat pump, as far as the frequency distribution of the machine performance.