The heat source forms the thermal basis of a heat pump system. It supplies the low-grade energy that is upgraded to a higher temperature level through the thermodynamic cycle. In industrial high-temperature heat pumps (HTHPs), this energy typically comes from waste heat streams generated during production processes, refrigeration systems, or auxiliary technical processes. It can also be sourced from the environment—for example, from ambient air, water, geothermal energy, or solar thermal systems. These sources supply the inlet temperature required for compressing the refrigerant in the compressor.

Waste heat can be classified as either directly or indirectly usable, depending on its temperature of the heat source. If the source temperature meets or exceeds the process requirement, heat can often be transferred directly via heat exchangers, without the need for a heat pump. If the temperature is lower, the heat pump steps in to elevate it—unlocking the potential of otherwise unusable low-temperature heat for process or space heating applications.

While environmental sources like ambient air, ground, or groundwater are common in building applications, industrial settings primarily rely on process-related waste heat sources, including:

• Process waste heat (e.g., from drying, evaporation, or cooling)
• Chilled water used for process cooling
• Flue gas condensation from boilers or district heating plants
• Industrial or sanitary wastewater streams
• Condensation heat from air-conditioning or cooling towers
• Humid exhaust air, including condensate from drying processes
• Server waste heat from data centres

These sources typically deliver temperatures in the range of 30 °C to 90 °C. High-temperature heat pumps such as SPH’s ThermBooster™ can raise these inputs to supply flow temperatures of up to 200 °C. This capability significantly increases the overall energy efficiency of industrial plants while reducing fossil fuel consumption and CO₂ emissions.

Key factors in system planning include the source temperature – especially the return temperature to the heat source – the volume flow rate, temporal availability, and the chemical composition of the medium. Additionally, the temperature and capacity demands on the heat sink side, as well as integration into existing systems, define the technical system design.

Unlocking internal waste heat potential is one of the most effective strategies for reducing industrial energy costs. A pinch point analysis is recommended to optimize waste heat utilization. At the same time, this approach contributes meaningfully to the decarbonization of large-scale heating networks and enhances energy efficiency across production environments.