PVT collectors were a major topic at the Eurosun conference held in mid-September in Freiburg, Germany. Three sessions featured presentations on new developments and projects in the field. Particularly valuable were the contributions by Bharat Chhugani from the German Institute for Solar Energy Research Hameln (ISFH) and Laetitia Brottier from French PVT collector manufacturer Dualsun. Both presentations included detailed monitoring results from PVT-assisted heat pump heating systems, demonstrating that seasonal performance factors well above 3 can be achieved. And both organisations are part of the German research project IntegraTE XL.
PVT collectors reduce the required ground loop area
Chhugani presented the design and implementation of a heating system combining brine-to-water heat pumps, PVT collectors and ground loops for two multi-family buildings near Hamelin, Germany. The two prefabricated timber buildings have highly insulated building envelopes and contain a total of 18 apartments. “Because of the existing mature trees, only a limited area of the gardens with a maximum of 532 m² per building was available for the ground loops,” reported the ISFH researcher.
During the system design, Chhugani calculated how much the required ground loop area could be reduced by installing PVT collectors on the roofs while still achieving a seasonal performance factor of 3.52 (see Figure 1). The calculations showed that installing 20 m² of PVT collectors per building would reduce the required ground loop area by around 20%. With 40 m² of PVT collectors, the ground loop area could be reduced by as much as 38 %. The developer, Hamelner Wohnungsbau-Gesellschaft, ultimately opted for the 38 % smaller ground loop area of 385 m². The pipe spacing was reduced to 0.5 m, and 48 m² of PVT collectors were installed. The collectors were supplied by German company TWL-Technologies. The aim of the building design was to develop two identical buildings that could be prefabricated in series while operating energetically independently.
