Heat Recovery Technologies

What is Heat Recovery?

Heat recovery is the process of using thermal energy that would normally be dissipated into the environment. For example, heat generated by compressors, welders, turbines, engines, pumps, furnaces, and sterilizers can be effectively recovered and reused. The recovered energy can be used to power central heating (CH), domestic hot water (DHW), ventilation systems, and other technological processes.

Where Can Heat Be Recovered?

Heat can be recovered from many places—here are some examples:

• Waste heat from production processes - this is heat that has been used to a useful extent in terms of the production process, while the remaining energy is released into the environment. Examples include firing furnaces, bread-baking ovens, boilers, pasteurizers, sterilizers, etc.
• Heat from ventilation - energy recovered from ventilation systems can be reused to heat or cool buildings.
• Heat from cooled devices - this is heat that must be dissipated under normal conditions by forced cooling, such as in air compressors, electric drives, injection molding machines, exothermic reactions, etc.

What Are the Methods of Heat Recovery?

The basic methods of heat recovery are:

• Recuperation: the process of transferring heat from exhaust air to supply air in ventilation systems.
• Recirculation: the reuse of heat in the technological process in which it was generated.
• Regeneration: the process in which thermal energy is stored and later used in another process.

Advantages and Disadvantages of Heat Recovery

Heat recovery offers numerous benefits, such as energy savings, CO₂ emission reduction, improved energy efficiency, and increased energy security. By recovering heat, companies can significantly reduce their energy intake from external sources, directly translating into lower operating costs. Reducing the use of fossil fuels and utilizing recovered energy also helps to significantly cut carbon dioxide emissions, which is crucial in the context of global efforts to protect the environment. Improved energy efficiency allows companies to obtain white certificates and other forms of financial support.

However, implementing heat recovery systems is also associated with certain challenges and limitations. The biggest challenge is the initial costs, which can be significant, especially with advanced technologies requiring large capital expenditures. Another challenge is the technical complexity involved in adapting and integrating heat recovery systems into existing processes. This may require advanced technical knowledge and specialized solutions. Additionally, some heat sources can be difficult to recover due to poor heat quality or dispersion, limiting the effectiveness of heat recovery technologies under certain conditions.

Heat Recovery Advantages:

• Significant energy savings: heat recovery can reduce energy consumption from external sources by up to 80%, leading to lower operating costs.
• CO₂ emission reduction: by reducing the use of fossil fuels, heat recovery contributes to lowering carbon dioxide emissions.
• Energy efficiency improvement: heat recovery increases a company's energy efficiency, potentially leading to the acquisition of white certificates and other forms of financial support.
• Energy security: ensures stability of energy supply by reducing demand from external sources.

Disadvantages of Heat Recovery:

• Initial costs: implementing heat recovery systems can involve high capital costs.
• Technical complexity: the need to adapt and integrate heat recovery systems into existing processes may require advanced technical knowledge and specialized solutions.
• Technological limitations: some heat sources can be difficult to recover due to poor heat quality or dispersion.

Where Can Heat Recovery Be Used?

A heat recovery system works best in industrial plants that consume large amounts of heat energy. Industries where this technology brings the greatest benefits include the chemical, food, metallurgical, and paper industries. In the food industry, heat from furnaces or cooking appliances can be used to heat water or buildings. In the metallurgical industry, heat from blast furnaces can be recovered and used in other stages of production—similarly in the paper industry, where heat from paper dryers can be reused.

An interesting solution that we developed for Umicore, a client in the chemical industry, was to recover heat from several processes and then use it to cover 50% of the demand for steam, which could be replaced by hot water in the area of media heating. Heat recovery included cooling of fumes after the dryer, air compressors, chemical reactors, and ammonia towers. The effect was achieved already in the first months after our audit.

Heat Recovery Application Examples

In practice, heat recovery can bring huge savings, as specific examples show:

At Schumacher Packaging, the use of a heat exchanger on the blowdown system resulted in:

• Annual savings: EUR 188,000
• Annual energy savings: 15,500 MWh
• Annual CO₂ emission reduction: 5,284 tonnes

At Swiss Krono, the use of waste heat from formalin production resulted in:

• Annual savings: EUR 2,3 mln
• Annual energy savings: 112,481 MWh
• Annual CO₂ emission reduction: 35,700 tonnes

Heat recovery from industrial processes is not only a way to significantly save energy but also to improve operational efficiency and reduce environmental impact. By using advanced recuperation, recirculation, and regeneration technologies, companies can effectively reduce energy consumption, lower CO₂ emissions, and improve energy security. Although implementing heat recovery systems may involve high initial costs, the benefits resulting from their use are invaluable. It is worth investing in heat recovery to increase your company's energy efficiency and contribute to environmental protection.