Testing of microencapsulated phase-change heat storage in experimental model houses under winter weather conditions
Bence Németh, Aurél Ujhidy, Judit Tóth, János Gyenis, Tivadar Feczkó
Abstract
A paraffin phase-change material (PCM) was entrapped by poly(methyl methacrylate) microcapsules that were loaded into plaster panels at high concentrations; these were used to build a model house. The PCM-plaster-lined and reference model houses were equipped with measuring instruments and heated during the daytime, to test their heat storage abilities in the studied wintertime conditions. A meteorological station collected the irradiation and outer temperature data; meanwhile, the external wall, internal wall, air, ceiling, and floor temperatures were measured using thermoelements. Electric energy consumption during heating was also recorded. Both houses were regulated by a controlled indoor temperature during daytime, followed by night-time free cooling. This regulation facilitated the complex evaluation of the heat-storage capabilities and their effects on the dynamic thermal behaviour and energy consumption of the PCM-plaster-lined and reference model houses. The PCM-plaster-lined model house exhibited a significantly lower temperature fluctuation; however, its energy demand exceeded that of the reference house, because its average internal temperature level was substantially higher during the test period. The global heat loss coefficient was estimated in a quasi-equilibrium state for the entire house. The heat loss was ~6.8% higher in the PCM-plaster-lined house, owing to the higher inner temperatures during the day. However, the heat loss coefficient in the PCM-plaster-lined house was ~7.8% lower, suggesting that latent heat storage can be economically used to maintain a constant inner temperature.