Energy-Efficient and Sustainable Heating System for Buildings : Combining seasonal heat storage with heat pumps and low-temperature heating systems

During gaps between high heating demand in winter and high heating production in summer, the application of seasonal thermal energy storage becomes important. However, heat loss from seasonal thermal energy storage has always been an issue. Therefore, in order to decrease heat loss and increase solar collector efficiency, low-temperature heat storage is recommended. Nevertheless, this temperature is not sufficient throughout the heating season, which means that a heat pump is recommended in order to use this low-grade source to produce a suitable temperature for the heating system. In addition, heat pumps have better efficiency when working with low-temperature heating systems. This study investigated the seasonal thermal storage in combination with heat pump and low-temperature heating systems, with the aim of finding a suitable size for thermal energy storage and collector area. The study showed that 300 m3 of storage volume and 55 m2 of collector area could cover 80 % of the total energy demand using solar energy.