A composite pipe material, co-created by Finnish companies QHeat and Exel Composites, has been shown to improve borehole energy efficiency by 10% at one QHeat’s geothermal wells at the site of the Lounavoima waste-to-energy plant. The glass fiber reinforced polymer (GRFP) material was proven to be suitable to the pressure and temperature conditions of underground applications, while providing the insulating capacity to improve energy efficiency in heat transfer.
Having previously worked with Lounavoima, QHeat was familiar with the plant’s requirements. It needed a cost-effective and sustainable solution to improve energy efficiency while meeting regulations. Prior to installing a heat storage system, the Lounavoima plant released its excess heat into the air during the summer. When ambient temperatures fell to -20°C in the Finnish winter, its emissions increased because of the supplementary oil burners needed to supply heat at peak times.
The energy saved by improving the plant’s storage efficiency equates to the heating requirements of 700 detached houses per year.
“The composite collector pipes improved the energy production and storage capacity of Lounavoima’s borehole by nearly 10 percent compared to the previous solution,” said QHeat CEO Erika Salmenvaara.
Bespoke solutions for subsurface challenges
The tailored composite collector pipes were developed to meet the Lounavoima plant’s specific needs, while also focusing on durability, sustainability, and recyclability.
The collector pipes needed to withstand their own weight two kilometers underground, while also insulating heat to ensure energy isn’t lost during transfer. Exel’s composite solution rose to the occasion, being metal-free, light-weight, optimized for flow and insulation, and recyclable. The choice of fiberglass might seem unconventional compared to acid-resistant steel or plastics. However, traditional materials weren’t a good fit for this case: metals conduct heat, and plastic lacks the mechanical strength required at such depths.
Composite materials can be applied well beyond geothermal energy, in areas such as wind and solar power, where their performance characteristics – lightness, insulation, corrosion resistance and long lifetime – deliver major benefits. This supports, among others, industries driving the green transition.
A collaboration with complementary strengths
The collaboration between the two parties was described as a “natural fit.” Exel Composites’ R&D department worked closely with QHeat’s engineers to tailor the composite tubes to the job’s specific environmental and performance requirements. The two teams went through several iterations, optimizing for sizing, connection methods, and thermal insulation vs mechanical strength trade-offs. Exel designed and manufactured the collector pipes, which QHeat installed using specialized tools
While QHeat owns the solution and patent for the geothermal well technology, Exel’s R&D team and decades of composites expertise played a crucial part in the co-creation project. Both parties were equally impressed by each other’s expertise.
“We got to work ambitiously and openly on a product that has the potential to launch us into new business areas and markets. We could demonstrate that the composite pipes have an estimated 50-year lifecycle and can be responsibly disposed of at the end of it,” said Pertti Kainu, Product Business Owner at Exel Composites.
Bringing Finnish engineering to international markets
The collector pipe project showcases how Finnish engineering and collaboration can accelerate the green transition. Designed, tested, and manufactured entirely in Finland, the Lounavoima collector pipes reflect both companies’ roots, but their sights are set firmly on international growth. QHeat is expanding in the Nordics and EU, while Exel’s international factories support smooth collaboration across markets.
“We’re taking QHeat’s thermal wells abroad, and Exel can bring their product development professionals into our international projects,” commented Salmenvaara.
Source: QHeat and Exel Composites
