Application of an unconventional thermal and mechanical energy storage coupled with the air conditioning and domestic hot water systems of a residential building

This paper proposes the application on microscale of an innovative trigeneration system with micro CAES (Compressed Air Energy Storage) – TES (Thermal Energy Storage) and the integration of renewable energy production, focusing on the potential use for air conditioning and domestic hot water systems. The system allows storing mechanical energy in the form of elastic and thermal potential of compressed air through two thermal storage units, HTTES (High Temperature Thermal Energy Storage) and LTTES (Low Temperature Thermal Energy Storage). The proposed system is tested on a single-family building in a warm climate. The analysis is carried out for integrated and independent operating modes. In integrated mode, the LTTES refrigerant charge and the vapor compression chiller operate simultaneously to cover the building’s thermal load. In this case the energy expenditure is only related to the power supply of the chiller. In independent mode, the cold storage and the chiller work alternately during evening operation to limit the absorption of energy from the distribution network. The results show that, in integrated operating mode with partial recirculation and internal temperature conditions of 26 C and 50% of relative humidity, the system reaches, in relation to the peak thermal load, a maximum operating time of 236 min. The minimum operating time of 26 min is reached using the full external air operating mode with an internal temperature of 26 C and relative humidity of 40%. In independent operation mode, it is possible to sustain the evening thermal load for up to a maximum of 5 h without electricity absorption from the distribution network.