Underfloor heating system model for building performance simulations

Abstract

The efficiency of heat pump systems is highly dependent on the temperature gap between the sink and the source side. Therefore, it is necessary to accurately model the sink side to enable the most accurate and holistic analysis of building energy systems. In both residential and non-residential buildings, underfloor heating systems are becoming more and more widely used. Their application can reduce the flow temperature of the heating system compared to a radiator and thus increase the efficiency of a heat pump system. This paper provides an underfloor heating system model including automatic parametrization according to prEN 1264-3:2020-02. Since the model represents a whole underfloor system, it consists at the system level of the distributor and several heating circuits and takes at the smallest level the heat transfer from a pipe element through different floor layers into account. The model is verified for the system requirements according to prEN 1264-2:2020-02. A parameter study with a variety of different underfloor heating parameters and floor layers shows that reductions of heat transfer in the underfloor heating system are compensated primarily by increasing the supply temperature. The highest influence on the temperature level of the system is exerted by the pipe spacing T, which raises the flow temperature by up to 10.9 K, from 36.6 °C (T = 100 mm) to 47.5 °C (T = 400 mm). The model is freely available on GitHub: https://github.com/RWTHEBC/AixLib/tree/issue890_HOMProject_FloorHeating