Simulation of a heat pump system for total heat recovery from flue gas

This paper introduces an approach of using an open-cycle absorption heat pump (OAHP) for recovering waste heat from the flue gas of a gas boiler with a system model. And equivalent energy efficiency is used to evaluate two other heat recovery systems that integrate an electric compression heat pump (EHP) or an absorption heat pump (AHP) with a boiler. The key factors influencing the systems are evaluated. The OAHP system efficiency is improved by 11% compared to the base case. And the OAHP system is more efficient than the AHP or the EHP systems, especially when the solution mass flow rate is only a little less than the cold water mass flow rate. The energy efficiency comparison is supplemented with a simplified economic analysis. The results indicate that the OAHP system is the best choice for the current prices of electricity and natural gas in Beijing. (C) 2015 Elsevier Ltd. All rights reserved.