A review on phase change materials (PCMs) for thermal energy storage implementations

Abstract

With the rapid developments in the industry and technology, the energy need is increasing. 80% of the CO2 emission in the atmosphere is caused by the use of fossil based fuel and this situation has a serious impact on climate change. Therefore, energy researchers/engineers mainly work on the development and improvement of the techniques in order to use renewable energy sources more effectively. In this context, intensive studies have been carried out in order to use the energy from the sun in the most efficient way, by active or passive means when it is needed. Because solar energy is a discontinuous energy source within day and seasons, its storage in thermal form is one of the commonly used techniques. The most effective and easiest way to achieve this is to exploit from phase change materials (PCM) directly or by developing them as a composite. In this context, PCMs are used in various research areas of energy storage and thermal management systems. Since, particularly, approximately 40–45% of the energy consumption in the world is corresponding to the consumed amount for heating, cooling and air conditioning in buildings, the use of PCMs in buildings directly or by integrating them with building materials makes them more important in terms of energy saving. For this purpose, the number of studies on the use of effective phase change materials (PCMs) that have the ability to store/release solar energy in the form of latent heat is increasing. In this short review, general information about PCMs that can passively store thermal energy is presented. The diversity of PCMs, the selection criteria in practical applications, the difficulties of use, the solvation ways and also their potential utility areas were summarized.