Impact of Buffer Sizing on Heat Pump Performances for Residential Applications

This paper analyzes the advantages and disadvantages of using heat pumps with buffers in terms of energy efficiency and cost, depending on the heating system used. The impact of buffer size is analyzed under different scenarios and with different heat pump sizing (power): single-zone and multi-zone apartments, radiator or under floor heating, and different weather conditions. In residential applications, the use of a buffer incurs additional purchase and installation costs, not to mention the space required for installation. This further motivated the present research work. A simulator based on a mathematical model is exploited; simulations are performed through Dymola and Matlab/Simulink environments. In order to provide an overall assessment of the heat pump performances, some significant Key Performance Indicators were analyzed such as the frequency of on/off cycles, the frequency of defrost cycles, the success rate of defrost cycles, and the frequency of oil return cycles.