Potentials of Zeotropic Mixtures with Large Temperature Glides as Working Fluids for Organic Rankine Cycles (ORC) and Heat Pumps

摘要

Nowadays, zeotropic mixtures with a temperature glide up to 15 K are the state of the art in air-conditioning.Less attention is paid to mixtures with larger temperature glides (LTG). The small number of research activitiescan be explained by the lack of promising applications as refrigerants in cooling applications. However, theseglides can be beneficial for heat pump applications and Organic Rankine Cycles (ORC), since these systemsmainly operate with sensible heat sources and heat sinks. The paper points out the potentials of LTG workingfluids in heat pumps and ORC and discusses fluid combinations for different temperature levels. The limits ofthese applications are identified, an overview about challenges reported in the literature are presented and theadvantages are demonstrated. Especially a new kind of ORC is presented, which operates as a heat transformerintegrated in an industrial heat recovery system.