How can you define and understand Phase Change Material?
Substances exhibiting thermodynamic properties as a result of the presence of high heat of fusion or latent heat are termed as Phase Change materials. The outcome of the latent heat presents the opportunity for storing and releasing large amounts of energy. The PCMs are capable of demonstrating such thermodynamic properties during the phase change, generally solid to liquid transition, resulting in the heat storage in accordance with the per unit volume of the substance. The PCMs can be classified as organic, inorganic, hygroscopic or even Solid-Solid PCMs. The implementation of the various kinds of PCMs in building construction is dependent on the advantages and the disadvantages that the materials pose in different environment conditions. The thermophysical properties of the PCMs are taken into consideration as selection criteria for the type of PCM for the materials for building construction (Qiu et al. 2017). It may be stated in this regards that the concept of implementation of PCMs for improving the insulation of building materials had been taken into account after the World War II. This research provides an insight into the classification of the PCMs based on their thermophysical properties, along with the techniques implemented for improving the insulation of building materials. In addition to that, this research investigates the various applications of PCMs, including the involvement in building construction.
Often issues with leakage of insulation are noted due to the implementation of high temperatures. However, the encapsulation of paraffin into small spheres, and thereafter mixing with concrete, aids in the building construction purposes. The techniques used in this regard and their efficiency are studied for the purpose of this research paper. Impregnation, immersion and direct mixing are techniques which are emphasized in this paper. Furthermore, the applications of PCM are studied and an evaluation is made regarding which of the techniques may be suited for the construction industry.
The study of phase change materials provides a concept regarding the efficiency of the materials, and it has been evident that the use of PCMs results in more energetically efficient buildings. A literature review of the PCM stated by several scholars has been discussed in this regards. The productivity and advantages offered by a variety of PCMs in the building construction industry have been illustrated in this research. In addition to that, the multiple techniques for enhanced PCM integration into building construction work have been mentioned and studied.
Phase Change Material can be described as a substance that has a heat of fusion, which is high. As it possesses this quality it can be melted or solidified at a specific temperature and then it can store as well as release huge amounts of energy. Phase Change Materials can be called as the units of latent heat storage or LHS too, as the substance while turning from solid to liquid or from liquid to solid releases or absorbs a lot of heat. The storage of latent heat can be done in a few ways and through the following changes in the phase of a material:
- Solid to liquid
- Liquid to solid
- Liquid to gas
- Solid to gas
While all these phases are present, PCM involves only the two initial phases, which are the solid to liquid and the liquid to solid phase. The phase change from liquid to gas has a higher degree of the transformation of heat than the solid to liquid or the liquid to solid transitions, the first phase change involves the utilization of high pressures or large volumes in order to store the materials in the gas phase and have been concluded as being impractical for the purpose of thermal storage. On the other hand the solid to solid phase transition is a very slow process that produces low heat. The solid to liquid transitions of PCM initially behave like the sensible heat storage or SHS where the temperature increases constantly log with the absorption of heat. However, the PCMs reach a certain temperature when they melt and then they can absorb huge amounts of heat without rising radically in the temperature. The PCMs are available at a diverse range of temperature that starts from -5 degree C to 190 degree C. Some PCMs are also available at the comfort range of the human beings, which is between 20-30 degree C and are quite effective as well because they are able to store heat 5 to 14 times more per unit volume than the conventional materials of storage like masonry, rock or water.
