Heat Pump system control strategies: comparison of two system layouts and evaluation of the energy saving potential from human behaviour and weather information

The present work is focused on the implementation of smart control strategies applied to a Ground-Source Heat Pump system (GSHP), for Space Heating (SH) and Domestic Hot Water (DHW) needs, in a Swedish single-family house. In particular, the developed rule-based control logics, using both a predictive and non-predictive approach, take into account human behaviour and weather information, such as the profiles of the DHW consumption and of the internal heat gains, and the solar radiation data. The study is carried out by means of TRNSYS® numerical simulations. An existing system model (Layout A), developed by Braida and Tomasetig from Polytechnic University of Milan [1], which includes a typical Swedish building, a single-speed GSHP unit, an auxiliary heater and a stratified storage tank, has been adapted to a different system layout (Layout B). The main difference is represented by the direct connection between the heating generation and distribution loops, since the storage tank is used for DHW purposes only. A comparison of the two layouts reveals an energy consumption reduction in the latter configuration, but with a lower indoor temperature stability. In order to evaluate the performance of the developed control logics applied to Layout B, a basic degree-minute on/off controller has been adopted as a benchmark. Considering the DHW consumption over the summer season, a potential energy saving is achievable thanks to the improved control logic. With reference to the Swedish heating season, the thermal comfort enhancement, deriving from the use of the internal gains profile and already shown in [1], is more consistent when a non-predictive approach is adopted. The highest potential in terms of energy saving and thermal comfort improvement is given by the simultaneous implementation of all the developed control logics, including the exploitation of the solar radiation data.