A novel compression-assisted double absorption energy storage heat transformer with high temperature lift

Absorption energy storage heat transformer (ESHT) is a type of absorption energy storage system designed to achieve temperature lift. The system addresses energy supply-demand mismatches and expands potential applications for low-grade energy. This paper proposes a novel compression-assisted double absorption energy storage heat transformer (CDAESHT) to improve the system performance. The dynamic characteristics of four operational modes with/without compression are comparatively analyzed. The performance of the CDAESHT and existing ESHTs is studied and compared. Results indicate that the CDAESHT achieves the maximum temperature lift of 95 degrees C while demonstrating superior performance over existing ESHTs. Compared to the conventional ESHT with a maximum lift of 37 degrees C, the energy storage density is improved from 15.61 kWh/m3 to 38.49 kWh/m3, the exergy efficiency is enhanced from 0.21 to 0.24, and the discharging time is increased from 66 min to 122 min. Moreover, the system performance exhibits excellent stability as the charging temperature increases. The proposed system demonstrates favorable economic performance and a lower environmental impact compared to gas and electric boilers. CO2 emissions are reduced by 11,022.77 kg (34.81 %) and 61,277.27 kg (74.80 %), respectively. This study can offer valuable insights for the advanced ESHTs.