Investigation of the Incorporation of Phase Change Materials in a New Design Underfloor Heating Panels

The global challenge of depleting nonrenewable natural energy resources, coupled with rising energy demands, is pressing. The building sector, consuming over a third of global energy production, underscores the need to enhance internal thermal comfort in buildings with minimal energy use. One effective method is integrating phase change material (PCM) into underfloor radiant heating systems. A novel design of underfloor heating panels (UFHP) with integrated free PCM has been introduced, investigating the availability of this design and its impact on surface temperature. The UFHP, made of extruded polystyrene foam (XPS) with four circular grooves for hydronic pipes, features PCM within a rectangular groove. A comparable reference panel lacks PCM cavities. Testing involved a fully controlled electrically heated hydronic system with varying inlet water temperatures and flow rates. Surface temperature distribution and uniformity were evaluated under heating and non-heating conditions to assess thermal comfort and panel performance. Results demonstrate significant improvement in surface temperature uniformity and, particularly during non-heating periods. The maximum difference in surface temperature between the modified model and the reference model reached 3°C at an inlet water temperature of 50°C. This integration offers maximal benefits during times when heating is not in operation.