New systems for converting waste heat into cooling, dramatically reducing refrigeration costs

In the food industry, refrigeration costs account for 30% to 70% of total energy consumption, depending on the type of production. However, a large share of the heat generated by technological processes—cooking, pasteurization, sterilization, drying—is wasted. New heat-to-cold systems radically change this model, transforming residual heat into useful cooling.

How heat-to-cold technology works

These systems are based on special thermodynamic cycles (e.g. reversed Stirling cycle, absorption/ammonia–water systems, or solid-state phase-change solutions) that capture waste heat at temperatures of 60–120°C and convert it into refrigeration energy. Instead of purchasing electricity for conventional compressors, cooling is effectively “self-generated,” powered by a resource that until recently was considered waste.

In practice, surplus heat is collected via heat exchangers, passed through the system’s thermal generator, and the resulting cooling is delivered to refrigeration rooms, rapid cooling tunnels, or storage facilities.

Direct applications in food processing plants

• Slaughterhouses and meat processors – scalding, cleaning, and sterilization processes produce large volumes of hot water. Heat-to-cold systems can cover 30–50% of cooling demand for cutting rooms and cold storage.
• Breweries – wort boiling generates heat that can be converted into cooling for fermentation tanks.
• Dairy processing – pasteurization releases heat at temperatures ideal for absorption-based cooling systems.
• Frozen food industry – rapid freezing tunnels can be partially powered by renewable cooling, reducing electricity consumption during peak hours.

Economic advantages

• 20–40% reduction in refrigeration costs, depending on the amount of available waste heat.
• Fast ROI: most installations achieve payback periods of 2 to 5 years, even shorter in countries with high energy prices.
• Reduced dependence on electricity, a major advantage in the context of volatile energy markets.
• Higher durability: absorption-based systems have few moving parts and require limited maintenance.

Climate benefits

Renewable cooling reduces both energy consumption and CO₂ emissions, especially when it replaces large compressor systems using refrigerants with high global warming potential. Some European plants have reported reductions of 400–800 tonnes of CO₂ per year.

Heat-to-cold technology is becoming one of the most promising solutions for the food industry. Converting waste heat into cooling is not just a technical innovation, but a complete paradigm shift: factories can become nearly energy-autonomous in refrigeration, significantly reducing costs and environmental impact.

(Photo: Freepik)