Benchmarking and Potential of Heat Pumps for Flue Gas Condensation

The use of environmental or waste heat with heat pumps, open absorption cycles or sorption heat pumps is an option for low carbon or high efficiency heat supply for industrial use. For one of the mentioned technologies to experience wide spread application it must offer economic advantages compared to other technologies. The evaluation of the economic viability is strongly dependent on boundary conditions, especially the cost of gas and electricity. The scope of this work is to introduce a new methodology, the specific annuity difference method. The developed methodology can improve on the one hand the comparison of different heat recovery technologies based solely on their cost and coefficient of performance (COP) and, on the other hand, allows for companies and researchers to identify if investment cost or efficiency improvement is more important to grant economic viability given a specific gas and electricity price. Additionally the maximum amount of heat that can potentially be recovered from the flue gas of gas boilers and gas turbines using an active condensing technology is compared for different COPs, temperature differences between cooled gas and heated water and different return temperatures, in order to quantify potential efficiency improvements for both technologies.