Test rig and experimental design for a high temperature CO2 pumped thermal energy storage system
Decarbonizing the industrial sector is a major challenge facing future energy systems. The industrial sector corresponds to a third of global energy consumption and CO2 emissions. The need to decarbonize this sector of the economy is evident, despite little progress in implementing low carbon technologies. Only 13% of heat was generated with modern renewables in 2022. Heat pumps have been outlined as a key technology in the transition to low-carbon heat sources for their high coefficients of performance. Understanding the benefits of heat pumps on a system level with thermal energy storage, concentrated solar thermal, and an ever-decarbonizing electricity grid is essential to transform the industrial sector. This work includes an overview of a system-level technoeconomic analysis, and the design of the testing facility hosted in the laboratory of KTH’s Heat and Power Division. The test rig will validate an R744 (CO2) high temperature heat pump to a TRL 5 by testing different industrial heating and cooling demand profiles. The types of profiles were chosen based on a review of the needs of major industrial subsectors. These include drying, steam, and simultaneous heating and cooling. The operating conditions of the test rig for each demand profile were determined through a combination of heat balances, common heat exchange correlations, and pinch analyses. Finally, this work presents expected operating modes for these profiles along with a preliminary process flow diagram of the test rig.