Heat and mass transfer in a novel device for energy recovery

This study investigates the performance of a heat pump-integrated energy recovery system designed for processing high-temperature industrial exhaust. The research specifically explores operational modes involving simultaneous heat and mass transfer, highlighting the synergy between condensation processes, latent heat release, and overall thermal efficiency. Through a numerical analysis, the system was evaluated across exhaust air temperatures of 20 to 50 °C and relative humidity levels from 10% to 90%, while utilizing glycol inlet temperatures of −10, 0, and 10 °C. The study further accounts for the influence of heat exchanger geometry and glycol-to-air heat capacity ratios. The data reveals that the moisture content of the exhaust stream is the most critical factor in defining the energy recovery ceiling. In scenarios featuring warm, humid air, vigorous condensation enables recovered thermal capacities to exceed 200 kW, reaching peak efficiency levels where the specific impacts of exchanger surface area and glycol flow rate are marginalized. In contrast, dry exhaust streams restrict latent heat exchange, causing the system's performance to become highly dependent on specific design configurations. While decreasing the glycol inlet temperature improves energy harvesting, it necessitates careful management of frost risks, particularly as the exhaust dew point nears 0 °C. These conclusions offer a framework for optimizing energy recovery hardware in industrial settings characterized by high-heat, moisture-laden air discharge.