High-temperature heat pumps: key technologies and industrial applications toward carbon–neutral process heating

Abstract

High-temperature heat pumps (HTHPs) are emerging as pivotal technologies for decarbonizing industrial heat supply by upgrading low-grade waste heat to meet diverse thermal demands. This review summarizes and analyzes the current state, applications and future trends of HTHPs from a carbon–neutral perspective. Core technological aspects—including cycle configurations, refrigerants, compressors, and integration strategies—are systematically analyzed. Thermodynamic comparisons reveal that cascade and coupled cycles can achieve temperature lifts above 100 °C under optimized conditions. The transition from high global warming potential (GWP) hydrofluorocarbons toward low-GWP hydrofluoroolefins, hydrochlorofluoroolefins, and natural refrigerants is accelerating. Large-capacity screw and centrifugal compressors are identified as key enablers for industrial-scale deployment. Typical industrial deployments of HTHPs across various fields are introduced, mainly structured around their application potential, integration characteristics, and implementation methods within energy-intensive sectors (e.g., paper manufacturing, textile dyeing). Future development will focus on high-power systems, advanced working fluid design, and digital control integration with renewable power and thermal storage. Collectively, HTHPs constitute an essential electrification pathway for achieving deep industrial decarbonization and carbon–neutral energy systems.