Comparison of two solar-assisted underfloor heating systems with Phase Change Materials

Abstract

In this work, two underfloor solar assisted heating systems without and with phase change materials (PCMs) are investigated energetically for a building of 100 m 2 floor area, which is situated in Athens, (Greece). The simulations are conducted with the commercial software TRNSYS 17. More analytically, flat plate collectors coupled to a storage tank are used while there is, in the first system, an auxiliary heater and in the second system, a heat pump, for supplying the extra heating demand when the solar potential is not sufficient. The PCM layer (BioPCM Q29/M91) is situated below the underfloor heating system, which operates with water, in order to increase the storage capacity. Moreover, this study compares the indoor temperature profiles of the building with and without a PCM layer on the floor and specifically in different cases by changing the area of the collectors and the thickness of the insulation layer. The results showed that the electrical energy consumption decreases on average 70% and 41% for the system with an auxiliary heater and for the system with heat pump respectively. Moreover, the application of the PCM layer on the floor in both systems gives an increase of the indoor temperature about 2 o C into the limits of thermal comfort.