Energy saving potential of a ventilation system with a latent heat thermal energy storage unit under different climatic conditions

Ventilation system with a latent heat thermal energy storage (LHTES) unit can be used to reduce building energy consumption, which stores the coldness of nighttime outdoor air in the LHTES unit and releases it to cool the fresh air during the daytime. The potential energy saving through the use of the system over a conventional ventilation system, however, has seldom been quantitatively evaluated. This study develops and validates a computational heat transfer model of the system, which takes into account two-dimensional heat transfer in phase change material (PCM). The effect of PCM melting temperature on the melted fraction of LHTES unit is investigated to determine the optimum melting temperature. This study then calculates and evaluates the energy saving potential of the LHTES system in summer for eight cities located in four different climate zones of China. The energy saving potential is assessed in terms of cooling energy supply, cooling energy supply ratio, net electricity saving and electricity saving ratio. The results show that the seasonal average cooling energy supply ratio varies from 39% to 194%, with a mean value of 85%, and the seasonal average electricity saving ratio ranges from 26% to 165%, with a mean value of 68%.