Performance and cost analysis of phase change materials with different melting temperatures in heating systems

Usage of thermal energy storage (TES) for storing energy is a favourable technology which is used in current years. The normal TES in building applications is water which is used in the heating system. Recently, PCM technology improvement helps to use different types of PCMs for increasing energy and exergy efficiency of TES system. In this present work, the effect of different PCMs with different melting temperatures on the energy and exergy efficiencies are investigated by considering the price of energy, exergy for each PCM type. The cost of lost energy and destroyed exergy are calculated for each PCM type in their life cycle and their share in total life cycle cost sketched as a circle diagram to show their importance. The amount of average lost exergy cost share is about 70.49%, average lost energy cost share is about 29.45% and average PCM price share is about 0.06% which means for having more optimum PCM choosing, the exergy concept have more significant role in choosing melting point of PCM than energy and the price of PCM. Finally, in the discussion part all of these data investigated together to help choosing the best PCM regarding the lowest total life cycle cost. ► High melting temperature of PCM will provide higher exergy efficiency in a heating system. ► PCM with higher melting temperature will reduce total life cycle cost of the heating system. ► The average exergy share in the total life cycle cost of the system is about 70.49%.