Cascade Heat Pumps Upgrade Industrial Refrigeration Waste Heat

Application Area: Industrial Heat Recovery and Process Heating Integration
Industry Sector: Food and Fruit Processing

Fruit processing operations demand simultaneous, continuous heating and cooling. At its facility in the Netherlands, Kervo relies on refrigeration for cold storage, while downstream fruit processing stages require high-temperature hot water and steam. Conventional food processing architectures address these thermodynamic loads through decoupled utility networks, dissipating refrigeration rejection heat into the atmosphere via cooling towers or gas coolers while burning fossil fuels in dedicated boilers to generate heat. To optimize site energy balance, Kervo sought to capture rejected refrigeration heat and upgrade it into usable industrial process heat.

Integrated Transcritical and Hydrocarbon Cascade Design
System designer and installer Servex engineered an integrated thermal system combining transcritical carbon dioxide (CO₂) refrigeration with a cascaded hydrocarbon industrial heat pump boasting 800 kW of heating capacity. The cold-storage rooms are chilled by the transcritical CO₂ circuit, where compressors and electronic expansion valves capture thermal energy from the cooling cycle.

Rather than rejecting this heat, the thermal energy enters a multi-stage hydrocarbon heat pump circuit. The first stage utilizes an R600a (isobutane) cycle to generate process hot water at 90°C. A secondary cascade stage running on R600 (n-butane) upgrades the thermal output further, delivering high-temperature energy to generate process steam at 120°C. Brazed plate heat exchangers facilitate heat exchange across circuits, while dedicated industrial screw compressors provide the temperature lift required to reach the industrial supply thresholds. Variable frequency drives modulate compressor motor speeds dynamically, matching refrigeration and thermal uplift to shifting factory processing demands.



Phased Deployment and Modular Scalability
System installation was executed across two distinct milestones to ensure operational continuity. The baseline transcritical CO₂ refrigeration system and heat capture circuits were commissioned in 2023, while the hydrocarbon industrial heat pump cascade entered commercial operation in July 2026. The thermal plant employs a modular, plug-and-play framework, allowing future heat pump modules to connect directly into existing piping manifolds without redesigning the primary refrigeration cycle.

Optimized Thermal Balance Across Processing Workflows
Deploying the integrated cascade architecture eliminated thermal waste from Kervo’s cold storage infrastructure. Supplying 90°C hot water and 120°C steam directly to production lines displaced primary fuel combustion in auxiliary boilers, closed the thermodynamic balance between cooling and heating operations, and established a scalable blueprint for low-emission industrial food manufacturing.

Edited by Romila DSilva, Induportals Editor, with AI assistance.