Energy harvesting of building skins - an innovative renovation for gas-free heating

Within the framework of the Horizon 2020 project ‘ENVISION’ we have developed a new invisible façade integrated collector panel with a colored solar harvesting coating. This coating system and façade panel is developed with paint company AkzoNobel, prefab element producer Emergo and The Netherlands Organization of Applied Research (TNO). The potential of thermal collectors integrated in the façade is surprisingly high with an annual energy solar gain of 2.5 – 3 GJ/m ² in a south oriented façade and still a 1 GJ/m ² in a north facing façade.

Within the framework of the ENVISION-project [1], the performance of these façade collectors were tested at SolarBEAT, the outdoor research facility for innovative solar energy products of TNO. The performance of these panels is measured for different coatings. Laboratory tests have shown that even for the white façade collector up till 35% absorption can be achieved, using a nano-technology modified coating system. This means that we can include the technology seamlessly in all buildings with different colors. It will be a new heat source for heat pumps, next to the commonly accepted sources; air and water (from for example ground loops).

After testing the solution at SolarBEAT, the technologies are demonstrated in demonstrations in Italy and the Netherlands. In Italy, the demonstration focuses at connecting the harvesting panels to a district heating network of the University of Genoa. In the Netherlands, three social houses in Helmond and three social houses in Eindhoven have been renovated using the panels in combination with heat pumps. In Helmond a prefab façade with integrated panels was demonstrated, as well as separate panels on the façade walls. In Eindhoven, besides panels on the façade walls, also an energy shed was developed and shown.

By using the façade collectors with a surface area of 15m ² as a cold source for a heat pump, sufficient thermal energy is harvested to completely heat a reasonable insulated row dwelling for a whole year, including a strong Dutch winter. In principle, the technology can also be integrated in pre-fab Roof solutions as well as provide cooling next to heating.