Experimental research on the use of phase change materials to come to passive solar energy concepts

An efficient and effective use of solar radiation is one way to come to sustainable development in the built environment. Because of an average temperature of 9.5 °C and an annual incoming solar radiation of 1,313 to 2,881 MJ/m2, The Netherlands seem on first sight not to be suitable for solar heating. Nevertheless, the passive use of solar radiation can offer many inexpensive opportunities in low exergetic heating applications. In this regards relatively little is known about the application of Phase Changing Materials (PCM) and their potential to save exergy in the built environment within building designs. This paper describes the development, execution and results of an experimental research project on the use of PCM in concrete floors for the accumulation of solar energy, in order to obtain a constant indoor temperature during day-night cycles. The results of this research can help to improve the energy performance of both new and existing buildings. To execute the experiment four different test boxes, representing scaled living rooms, were constructed. Their windows are oriented to the South to make optimum use of solar radiation. Two boxes have concrete floors with microencapsulated PCM’s, while the other two are without PCM’s. Two boxes are insulated with thick heavy insulation material and two have thin light insulation material. During the experiment the outdoor weather conditions and the temperature of the concrete floors are being measured in order to gain more insights in the practical use of PCM within the Dutch moderate climate. The first results show that concrete floors containing PCM can have a steadier temperature gradient than floors without PCM. The PCM makes it possible to come to lower maximum temperatures and higher minimum temperatures of the concrete floor, and hence, of the indoor air.