Transient supply-demand matching and numerical parametric study of solar absorption thermal battery for space cooling

Efficient use of renewable energy, e.g., solar energy, is an important pathway towards net-zero energy buildings and carbon neutrality. However, renewable energy is difficult to be fully utilized due to its instability and intermittency. Thermal energy storage technologies applied in buildings can bridge the gap between renewable energy sources and heating/cooling demands. This study employs a solar absorption thermal battery (SATB) in a building for space cooling. The annual dynamic performance of the SATB is investigated and compared in four representative cities by simulation using an experimentally validated model, considering transient supply-demand matching. Besides, parametric studies are conducted for the SATB designed with different solar collector sizes and solution charges. Results indicate that the SATB achieves satisfactory cooling met ratios (MRs) in different climates when 0.49 m2 solar collector is equipped for each square meter of the serviced room. The highest cooling MR of 0.95 is obtained in Singapore, with an energy storage efficiency (ESE) of 0.66 for the ATB unit, a system ESE (solar-to-cooling) of 0.24, and an energy storage density (ESD) of 125.8 kWh/m3. The maximum ESEs of the ATB unit and the SATB system are 0.71 and 0.30, respectively. The highest ESD of 157.1 kWh/m3 is achieved by the SATB system, which is much higher than the sensible and latent thermal batteries for space cooling. This paper demonstrates a transient supply-demand matching operation scheme of the SATB system in different climates with excellent annual performance, which can facilitate the promotion and development of ATB technology.

Automated summary

Efficient use of renewable energy, such as solar energy, is crucial for achieving net-zero energy buildings and carbon neutrality. However, the instability and intermittency of renewable energy make it challenging to fully utilize. This study explores the use of a solar absorption thermal battery (SATB) for space cooling in buildings. Through simulations and parametric studies, the SATB is found to achieve satisfactory cooling in different climates, with the highest cooling met ratio of 0.95 in Singapore. The SATB system also demonstrates high energy storage efficiency and density, making it a promising technology for promoting renewable energy utilization in buildings.