Using of phase change materials in building energy systems

As the result of foreign researches, phase change materials gained upon [1]-[4]. With our paper we would like to draw attention to the usage of these materials, as the next level of heat accumulation. Phase change materials (PCM) are materials used for storing heat energy. To do that these materials use latent heat in the storing process, so PCMs store heat with higher density and release it, when it is necessary. The biggest advantage of these materials is storing huge amount of heat energy with low temperature difference, saving energy and space. In our paper we present the progress of phase change, show the problems with these materials and examine present researches to improve the property of phase change materials. PCMs usually used for storing heat to provide constant temperature that is why these materials are most commonly used in HVAC systems. We can use PCMs in heating systems, built into storages, cooperating with boilers, or we can integrate these materials to wall structures to reduce the effect of outside temperature. In our research we examine a new application, where we integrate a surface heating/cooling system by placing PCMs as different layers of a wall structure. With EnergyPlus software we specify the best position, size and shape of the phase change materials and we also test in which weather conditions is the best to use these materials. We validate the simulation with our own thermal model to make sure it is working properly. Our calculations are based on the heating and cooling energy usage of the building and the level of thermal comfort. Finally we make an economic analysis, in return and the period that our investment pays which we test the off.