Dynamic performance analysis of adsorption heat transformer system driven by large pressure jump for low-grade waste heat upgrade

Upgrading low-grade industrial waste heat to higher temperatures plays a crucial role in improving energy efficiency and advancing sustainable development. In this study, a comprehensive dynamic performance analysis of a dual-bed adsorption heat transformer (AHT) system driven by a large pressure jump is conducted to upgrade the low-grade waste heat. The AQSOA-Z05/water working pair is investigated under constant flow output (CFO) and constant temperature output (CTO) modes. The theoretical maximum temperature lift potential governing adsorbent selection and operating conditions is thoroughly explored. Compared to the CFO mode, the CTO mode is found to provide more stable and controllable high-temperature output suitable for practical applications while achieving a higher specific heating power. Further, key parameters influencing system performance, such as adsorption connecting pipe diameter, target temperature lift, ambient and waste heat temperatures, are systematically analyzed under the CTO mode. Ambient temperatures of 0–30 °C facilitate stable operation, whereas waste heat below 70 °C leads to performance deterioration. To bridge the variable flow output under the CTO mode with heat load demands, integrating a heat storage tank and control system is suggested. The insights provided are expected to furnish valuable guidelines for the design and optimization of the AHT system, thereby facilitating more effective utilization of waste heat and contributing to sustainable industrial practices.