Buildings count for about 40% of the final energy consumption in Europe, and more than half of it is needed for space heating and cooling. Improving the energy efficiency in buildings is therefore a key challenge for the reduction of CO2 emissions: more specifically, space heating and cooling needs show a large potential for reduction, if only buildings could benefit from better insulation at an affordable cost.
The NanoPCM consortium developed a low-cost insulating polyurethane (PU) foam for the sustainable construction of buildings, able to store and release the energy within a closed area with outstanding performances. In winter, a building can then store the heat from the indoor environment during the day and release it at night when the temperature is cooler. In summer, the foam provides an enhanced insulation from the outdoor temperature, contributing to the indoor comfort.
The innovation lies in the successful integration of high performance Phase Change Materials (PCM) microcapsules into the foam, a real technological challenge: indeed, while PCM show an excellent potential for storing heat, they experience limited structure stability as well as poor heat conduction. The solution lies in encapsulating the PCM within a polymer matrix to obtain a stable PCM form. The thermal performance of the microencapsulated PCM is enhanced by adding nano-materials. Additional advantage, the synthesis of PCM microcapsules is performed through a sustainable manufacturing process presenting two key aspects in terms of resource efficiency:
· The PCMs can be based on by-products of different industries, as for instance the glycerine produced in biodiesel industry (upcycling of these secondary products);
· The microencapsulation is performed through an innovative spray-drying process that avoids waste production.
Phase Change Materials are then integrated to standard building insulation foams: the foam panels can be installed on walls and roofs following the existing standard procedure in building, avoiding any additional burden in the construction phase. Two demonstrators were built up in Poland and Spain to monitor the NanoPCM solution performance, showing promising results.
The laboratory test results showed a capacity to store 5 times more heat per unit volume than standards insulation foams, without any deterioration after numerous cycles of heating and cooling, ensuring a high performance over the entire building’s lifetime. In addition, when heating the samples under controlled environment, the NanoPCM products are maintained cooler than traditional foams, leading to a better insulation from the outside environment.
The buildings that will use such solution are then expected to increase their energy efficiency by at least 12%, with an estimated payback time of 2 years, a performance beyond the initial project target. Moreover, the results from the Life Cycle Assessment analysis showed a lower environmental impact when manufacturing and using the NanoPCM solution in buildings comparing to competing solutions on the market.
Why did it work?
The NanoPCM consortium, led by Acciona Infraestructuras -a leading European construction company based in Spain- channelled the synergies between complementary competences including Phase Change Materials expertise, thermal engineering, chemical engineering and Product Life Cycle analysis.
The project, completed in mid-2013, benefited from Public grant partial funding for R&D through the European Commission’s 7th Framework Programme (FP7-Nanosciences, nanotechnologies, materials and new production technologies, GA 260056).
A PCM pilot plant is operational with a maximum production of 80 tons per year, enough to insulate an area of 50000 m2 (the technology maturity is estimated at TRL 7). With regard to the innovative microencapsulation process, two patents were submitted (EP 2119498 A1; ES 2306624 A1).
Several industrial companies showed interest in incorporating the NanoPCM solution into their business units and feasibility studies are on-going.