Revolutionizing Industrial Heating and Cooling with Smart Waste Heat Recovery
Think about the last time you boiled water for pasta. Once the pasta was done, you probably poured that hot water straight down the drain without a second thought. Now, imagine that waste on an industrial scale…. factories across Europe do the same thing every single day with the heat they generate.
The problem? Industries consume over 3,000 TWh of energy annually in the EU, with heat requirements accounting for about 60% of this total. Yet, instead of capturing and reusing that energy, most of it just… disappears.
Similarly, cooling is a crucial yet energy-intensive process, especially in industries like food and beverage, pharmaceuticals, pulp & paper, and biofuels. In some sectors, cooling can account for up to 50% of total energy consumption.
This is where RE-WITCH comes in!
Funded by the Horizon Europe programme, this project tackles one of the biggest inefficiencies in industry: how to stop wasting heat and start using it to produce cooling and heating. A key project report is now out, “First release of industrial cooling needs and RE-WITCH technology specifications”, as a background study providing a comprehensive analysis of industrial archetypes and evaluating their suitability for RE-WITCH technologies.
The Challenge: High Energy Demand for Heating and Cooling
Cooling demand and the availability of waste heat sources are analysed, including renewable energy systems, in key industrial sectors: Food & Drink, Pharmaceutical, Biofuels, and Pulp & Paper. It characterises specific industrial processes (archetypes) within these sectors, focusing on key cooling demand parameters such as temperature levels and total energy consumption.
First, sectorial cooling demand is analysed based on data from literature. The Food & Drink sector demonstrates the highest cooling demand with the lowest temperature requirements, while the Bio-fuel sector exhibits the lowest demand. Detailed archetype descriptions follow, highlighting key processes within each sector. For the Food & Drink industry, dairy and beer processes are analysed. In the Pharmaceutical sector, ointment oil production serves as the archetype. The Kraft pulp-making process is selected for the Pulp & Paper sector, and biofuel archetypes are based on a widely reported production method. These descriptions illustrate that the lowest cooling temperature, approximately 4°C, is required in dairy and beer production.
Highlights include:
🔹 Food & Beverage: Requires low temperatures for chilling, freezing, and storage, while also demanding high temperatures for processes like pasteurization and sterilization.
🔹 Pulp & Paper: 93% of energy consumption comes from heat for steam generation, yet cooling is also essential for chemical stabilization and equipment maintenance.
🔹 Pharmaceuticals: HVAC systems account for over 50% of total energy use; strict temperature control is required for product integrity.
🔹 Biofuels: Both high-temperature processing (up to 250°C) and low-temperature cooling (below 30°C) are required at different stages.
How RE-WITCH Works: Transforming Waste Heat into Energy
RE-WITCH is developing thermally– driven cooling and heating technologies for industrial processes, optimizing the use of low-grade waste and renewable heat through new generation of adsorption and absorption chillers.
The report also outlines the basic requirements for adsorption and absorption technologies in these sectors. Adsorption systems, leveraging solid sorbents and low-grade heat, can achieve high efficiency with thermal and electric coefficient of performances (COPs) of 0.65 and >20, respectively, while ensuring compactness and cost-effectiveness. Absorption systems utilise lithium bromide-water pairs and innovative hybrid designs to address limitations such as crystallisation risk and narrow temperature ranges.
The Technologies behind RE-WITCH:
- Adsorption Chillers: Leverages the capacity of solid sorbent materials to adsorb and desorb water vapor, utilizing low-grade waste or renewable heat to drive the cooling process. This innovative approach eliminates the need for mechanical compressors, making it an energy-efficient and sustainable solution for industrial cooling applications.
- Hybrid Absorption Chillers: Integrates a mechanical vapor compressor in the absorption cycle, between the evaporator and the absorber. This hybridization significantly enhances system performance by leveraging the advantageous characteristics of both absorption and compression cycles.
- Dual Evaporator/Absorber Chillers: This architecture facilitates simultaneous cooling at two distinct temperature levels (for instance, 10°C and 20 °C), rendering it appropriate for industrial applications that demand variable cooling requirements. The strength of this configuration lies in the flexibility obtained by allowing each pair of absorbers and evaporators to operate independently, resulting in the elimination of the series flow configuration observed in conventional dual evaporator configurations. This parallel configuration reduces crystallization risks and optimizes the utilization of heat transfer surfaces.
Real-World Impact: Heating & Cooling in Industrial Sectors
RE-WITCH solutions are designed for direct integration into industrial processes, maximizing waste heat use.
💡 Pulp & Paper Industry:
The Pulp & Paper industry generates significant low-grade waste heat from processes like digesters, multi-effect evaporators, and air compressors (if any). Adsorption chillers are highly suitable here due to their ability to operate efficiently on low-grade waste heat (e.g., <90 °C), aligning perfectly with the industry’s waste heat characteristics.
💡 Breweries & Food Industry:
The brewery industry produces substantial low-temperature waste heat during boiling (in the Kettle/Copper), wort cooling, and from the hot liquor tank. Adsorption chillers can efficiently utilize this heat to meet the cooling demand for the fermentation and conditioning stages.
💡 Pharmaceutical Manufacturing:
The ointment manufacturing process involves significant cooling requirements, particularly during the cooling and homogenization step, where temperatures need to be reduced from 70 °C to 30–35 °C. Adsorption chillers are ideal due to their ability to utilize low-grade waste heat (e.g., from boilers or heated liquid phases) to provide cooling without reliance on high electricity consumption.
💡 Biofuel Plants:
The biodiesel production process involves several stages where low-to-moderate temperature waste heat (50–100 °C) is available, such as methanol recovery, transesterification, and biodiesel drying. A dual evaporator/absorber absorption chiller is ideal for this application due to its ability to handle multiple cooling demands simultaneously and optimize energy usage. For instance, this technology can provide cooling at the phase separation and washing stage simultaneously.
The Future of Sustainable Industrial Energy
By maximizing waste heat recovery, RE-WITCH provides industries with an efficient, cost-effective path to sustainability. Whether through low-temperature adsorption chillers or hybrid absorption heating and cooling, these next-generation solutions are setting the stage for a more energy-resilient future.
