Chapter 11 Economic and Environmental Optimization of Rotary Heat Exchangers: A Closer Look at the Conflict Eloy Melian , Harald Klein , and Nikolaus Thißen Abstract Rotary heat exchangers belong to the most efficient heat exchangers for gas streams. This technology is commonly used in power plants, paint shops and heating, ventilation and air conditioning systems. Yet an optimization taking into account both economic and ecological aspects is absent in literature. This work uses a simulation model developed at the Pforzheim University of Applied Sciences, combined with LCA and economic data to optimize rotors. From an environmental perspective, the use phase is where the bigger impacts take place. In the economical side, the use phase is also the most important. For the optimization, a commer- cial software for this purpose is used. The results show a conflict between the two possible optimization goals. Additionally data of two commercially available rotary heat exchangers from the Eurovent Database are also compared to the results from optimization via simulation and there is evidence that in some specific cases an improvement in the environmental or economical aspect can be done without compromising the other aspect. Keywords Rotary heat exchanger · Thermal wheel · Optimization E. Melian (B ) · N. Thißen Institute for Industrial Ecology (INEC), Pforzheim University of Applied Sciences, Tiefenbronnerstr. 65, 75175 Pforzheim, Germany e-mail: eloy.melian@hs-pforzheim.de N. Thißen e-mail: nikolaus.thissen@hs-pforzheim.de H. Klein Technical University of Munich, Bolzmannstr. 15, 85745 Garching, Germany e-mail: harald.klein@tum.de © Springer Nature Switzerland AG 2021 S. Albrecht et al. (eds.), Progress in Life Cycle Assessment 2019, Sustainable Production, Life Cycle Engineering and Management, https://doi.org/10.1007/978-3-030-50519-6_11 145