Experimental investigation of the PCM-EG radiant floor heating driven by ASHP with advanced heat transfer enhancement

Abstract

Radiant floor heating systems (RFHSs) provide superior indoor thermal comfort environment compared to other exist heating methods. Recently the integration of phase change materials (PCMs) as thermal mass within underfloor heating structures has demonstrated potential to reduce operating costs and enhance thermal comfort by enabling a quicker heating response due to their excellent heat retention properties during the heating period. For domestic buildings, Air Source Heat Pumps (ASHPs) recognised as a highly efficient heating technology, are increasingly adopted to meet heating and cooling demands while contributing to CO₂ emissions reduction targets. This study focuses on leveraging ASHPs to supply heat for the PCM-enhanced RFHSs, introducing an improved heating method for residential buildings to address heat demand and reduce the power consumption of ASHPs. The research aims to advance scientific understanding and establish a foundation for future studies on sustainable and efficient heating technologies. This study investigates the development of a novel sustainable and highly efficient thermal energy retention system through laboratory engineered composite PCMs integrated into RFs powered by ASHPs. Such systems are crucial to addressing current and future heating demands in the UK. This work examines the impact of system configuration, constituent materials and design parameters on the thermal and energy performance of RF heating systems incorporating composite PCM with enhanced expanded graphite (PCM-EG). The study has shown that PCM-EG used as thermal mass in RFHSs can achieve 37 % higher heat retention capacity compared to systems utilising a metal mesh. Additionally, PCM-EG combined with copper powder maintains the floor surface temperature 0.7 °C higher than PCM-EG alone, further reducing the power consumption of the ASHP.