A hybrid resorption-compression heat transformer for energy storage and upgrade with a large temperature lift

Heat transformers reveal significant potential for primary energy savings in domestic and industrial processes, which can use different heat sources as driving force to provide the heat or cooling. In this paper, a hybrid resorption-compression heat transformer is presented, which aims to upgrade the heat source e.g. industrial waste heat or solar energy with a large temperature lift. Performance of hybrid heat transformer is also compared with that of multi-stage sorption type. Results indicate that with heat source temperatures ranging from 40 °C to 90 °C, energy and exergy efficiencies of hybrid heat transformer decrease from 0.429 to 0.403 and from 0.8 to 0.64, respectively. Energy efficiency of hybrid type is a bit lower than that of basic resorption transformer but almost double higher than that of multi-stage cycle. For different operating parameters, mass ratio and global conversion rate have larger influences on thermal performance than isentropic efficiency of compressor. Also hybrid resorption-compression heat transformer is prospective for domestic heat application through the integration with solar photovoltaic thermal collector. When heat output temperature ranges from 50 °C to 70 °C, it could ensure that the heat density is higher than 1000 kJ·kg_am⁻¹ with an energy storage function.