Exel Composites and geothermal technology expert QHeat have completed their R&D project. The project revolves around providing composite tubes to store excess heat energy at the Lounavoima waste incineration plant located in Salo, Finland. Simulations found that glass fibre reinforced polymer (GFRP) tubes should allow the plant to store 14 GWh of heat in underground wells.
Exel Composites
Lounavoima geothermal plant.
Before installing a heat storage system, the plant released its excess heat into their air during the summer months. When ambient temperatures dropped to -20°C during winter in Finland, its emissions increased because of the supplementary oil burners needing to supply heat at peak times. By introducing these storage solutions, the plant can contain enough energy to heat 700 detached houses per year.
“60 per cent of all EU heat production comes from fossil fuels, and the remaining 40 per cent is still mostly combustion, like natural gas or waste incineration,” said Erika Salmenvaara, CEO at QHeat. “In the context that half of global energy use is for heating, we see the environmental gains that electrification of heating can provide.”
Salmenvaara continued, “It’s not perfect. Electrification of heating puts significant strain on the world’s ageing power transmission infrastructure, but innovative engineering can help there too. Grid-enhancing technologies are advancing rapidly, and, besides, heat pumps deliver up to 600 per cent more energy efficiency than using electricity directly.”
About the R&D project
The global composites manufacturer’s R&D department worked with QHeat’s engineers to tailor the composite tubes to the application’s specific environmental and performance requirements. The teams went through several iterations, working to optimise sizing, connection methods, and thermal insulation vs mechanical strength trade-offs.
GFRP is ideal for the pressure and temperature involved with underground applications. The partnership focused on the insulating capacity, ensuring energy efficiency in heat transfer is as high as possible.
“Heat preservation combined with the right mechanical performance was the biggest criterion to satisfy with these pipes,” said Tiina Uotila, Technical Sales Manager at Exel Composites. “However, we collaborated with QHeat to understand how we could make them easier to assemble and install, and to make sure that we have a defined, sustainable end-of-life route.”
Uotila continued, “Instead of going to landfill, these pipes will be co-processed into cement, where the reinforcement replaces raw materials and matrix replaces fuels.”
“I was impressed that Exel Composites’ head designer came on site with us in Salo to see the first pipes installed,” concluded Salmenvaara. “I also had the chance to visit Exel’s Mäntyharju factory in Finland. Then I understood its expertise, its design capabilities and the quality of its products.”