CHARACTERIZATION OF SELECTED PHASE-CHANGE MATERIALS FOR A PROPOSED USE IN BUILDING APPLICATIONS

摘要

The generally positive trend of ever-stricter requirements for the thermal insulation properties of building envelopes, leading to a significant reduction in the heat losses of modern buildings, has also brought about some negative aspects. Modern light-weight buildings with high-thermal-resistance envelopes are prone to overheating in the summer due to both solar and internal heat gains. This problem is often solved by installing mechanical cooling (air-conditioning) that leads to an increase in the energy consumption and, since electricity is mostly used to power the air-conditioning systems, the increase in the energy consumption for cooling can offset the heating-energy savings in terms of primary energy. A lot of attention has therefore been paid to the other means of temperature control in buildings, such as night-time ventilation and/or the building-integrated thermal storage. The phase-change materials that can store a rather large amount of heat in a narrow temperature interval around their melting point seem to be particularly suitable for this purpose. There are many ways of integrating PCMs into the building structures as well as the techniques that employ that extra thermal-storage capacity to provide thermal comfort for the occupants. This paper deals with the results of the laboratory testing of selected organic and inorganic phase-change materials for integration into building structures. Differential scanning calorimetry was used to obtain the melting ranges and enthalpies of fusion of the selected materials and thermogravimetry was used to explore the thermal stability (decomposition) of the materials at higher temperatures.