Industry-related greenhouse gas (GHG) emissions have increased continuously in recent years. Although industries share of global gross domestic product is declining, worldwide greenhouse gas (GHG) emissions from industry and waste/wastewater grew from 10.4 GtCO2eq in 1990 to 15.4 GtCO2eq in 2010. This represents over 30% of global GHG emissions, more than from either construction or transport.
Global energy demand is expected to increase 40% in the next 25 years, therefore it is vital to develop solutions to improve fuel use and efficiency in large energy-consuming processes. Energy harvesting techniques have the potential to recover 20% (140 terawatt-hours) of the waste heat energy lost by industry. This implies a reduction of 98 million tonnes of CO2 emissions per year, yielding potential cost savings to industry of 2.1 billion per year.
To realise this potential, solutions for waste heat recovery must become more adaptable to different industrial facilities and lower their maintenance costs. Thermoelectric technology could provide a commercially-viable means of achieving these goals.
LIFE-HEAT-R was a close to market project that aimed to demonstrate a new technology for directly converting waste heat into electricity, based on a thermoelectric principle called the Seebeck effect. The technology consisted of a modular unit using multiple thermoelectric generator cells controlled through a patented programmable control unit based on system-on-chip technology.
This technology would be demonstrated in industrial sectors with high levels of waste heat emissions, through five pilot sites (classified by temperature ranges) that would permit part of the wasted energy to be recovered in the form of heat and transformed into electricity. This would allow the energy to be used for other activities and processes. The net effect would be to reduce CO2 and other GHG emissions, due to the improved resource efficiency for the whole process.
The LIFE-HEAT-R project team developed and demonstrated highly-innovative technology that marked a break-through in the field of energy recovery and resource efficiency. The technology allows the direct conversion of heat generated by industrial processes into electricity, based on a thermoelectric principle called the "Seebeck effect". The project team designed, manufactured, installed and tested five prototypes incorporating the HEAT-R technology at five different industrial sites (Bodegas Torres, Distiller, Gomà Camps, Cementos Molins and CELSA), under various environments with different technical approaches. All the prototypes were composed of modular "Waste Heat Recovery Units" (WHRUs) that use multiple thermo-electrical generation cells (TEG cells), associated and controlled through a programmable unit based on "System-on-a-Chip" technology.
The project team faced numerous technical challenges and drawbacks, mainly linked to the high innovation level of the technology and to the COVID-19 pandemic. However, sufficient monitoring data was obtained to assess the technical viability, efficiency, and cost-effectiveness of all the prototypes. The technology was shown to be viable for generating electricity from residual waste heat. Its modular conception enables the retrofitting of existing equipment like boilers or kilns, and also its inclusion into new installations or equipment. The team concluded that the HEAT-R technology can be viable if coupled with boilers, , Yankee dryers, and clinker kilns.
Efficiencies obtained with the prototypes were between 1.94% and 4.24%, the maximum power generated varied between 14 W and 96.5 W, and the power density was between 32 and 566 W/m2. The performance, and hence the environmental benefits obtained, depended on several parameters, such as operating and ambient temperature, TEG cell quality, insulation materials, the heat collector type and the cooling methods. The most efficient prototype was the water-cooled device in direct contact with the waste heat source installed at the Distiller’s site ( boiler). This device reached a power density of 565.80 W/m2 and an efficiency of 4.24%.
Further technical developments and cost reduction will be necessary to prepare the technology for the international market, but project beneficiary, start-up company AEINNOVA in Catalonia (Spain), is confident that this will happen within the next few years. The company has attracted various post-LIFE funding to further improve the technology, including a European Innovation Council (EIC) accelerator grant in 2021.
The project’s HEAT-R technology will help industry comply with EU Clean Energy Transition policies. It enables the harvesting of waste heat from any heat surface, enabling part of the heat produced by industrial processes to be reused to generate electricity instead of being lost to the environment, thus improving the overall energy efficiency of industrial processes.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).