Experimental and simulation study on a new gradient waste heat recovery system with a wider application range

This paper proposes a cascade sustainable waste heat recovery technology with low power consumption and the ability to recover waste heat in a wider temperature range, namely, the Absorption-Compression Coupled Heat Pump System. Experiments and simulations were conducted to reveal the effects of different factors on system performance. The results demonstrate that the coefficient of performance and exergy efficiency of the new system increase with an increase in generator outlet water temperature. The coefficient of performance of the new system decreases with an increase in supply heating water inlet water temperature, while the exergy efficiency increases with an increase in supply heating water inlet water temperature. As intermediate temperature increases, the coefficient of performance of new system shows a trend of first increasing and then decreasing, the total heating shows a trend of first increasing and then stabilizing, and the exergy efficiency shows a decreasing trend. Compared to single-effect absorption heat pump system, the new system can recover heat at lower heat source temperatures, and compared to compression heat pump system, it can reduce electricity consumption. Finally, by comparing with experimental data, it was found that the proposed model has good reliability, with a comprehensive error within ±7 %.