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Solar Thermal Collectors from Kvelsrud in Norway to Belgrade

- to produce hot water for consumption, and provide surplus heat to one of Europe’s largest district heating networks

Inaventa Solar is one of the few Norwegian solar energy companies basing its offering on its own production, and sales of systems and solutions produced in Norway. Since the foundation of the company in 2019, Inaventa Solar has invested millions into the establishment of a new “Beyond State of the Art” manufacturing facility at Jevnaker in Norway.

Production has already commenced, and we are in the process of delivering the first installation to Belgrade, Serbia. 72 square meters of solar heat collectors will be installed onto the roof of the UN primary school in Belgrade, providing hot water for the sanitary installation and general consumption. Furthermore, the surplus heat will be provided back into the city’s district heating system - one of the largest district heating networks in Europe.

Solar heat collectors integrated into the roof covering

The school building houses 1400 students in 55 classes. The school has a modern design, for which the solar thermal collectors fit perfectly. The solar collectors are integrated into the easterly tilted roof, and will form a natural and harmonic part of the overall school building In addition to traditional classrooms, the school houses special function rooms, and offices, as well as a gym, and courts for basketball, volleyball, football and team handball. The hot water consumption is relatively high, but the Inaventa Solar solar heat collectors will have sufficient energy production, so that there will be a surplus of heat, which will be channeled out into the district heating network connected to the school.


Solar heat into the district heating network

The purchaser for the solar heat collector installation is Beoelektrane, a company providing district heating to more than half of the 1.65 million citizens of Belgrade. The district heating network in Belgrade is one of the largest in Europe. Over the last decade, Beoelektrane has undertaken extensive upgrades of the district heating network to improve the energy efficiency and adapt to environment friendly energy provision. One of the sub-networks has been converted to a low temperature network, where building-integrated solar collectors are contributing to the energy balance, alongside other technologies such as heat pumps. It is into this low temperature network that the Inaventa Solar solar heat collectors will provide the surplus heating from the UN school, as a part of a prosumer arrangement.

Demonstration installation under the initiative of the EU Commission’s Horizon 2020-project RELaTED

The installation at the UN school is one of several demonstration projects under the initiative of the EU Commission’s Horizon 2020 project RELaTED, where both Beoelektrane and Inaventa Solar are partners. RELaTED focuses on innovative solutions for thermal energy provision from renewable energy sources into low temperature district heating networks. The application of solar thermal energy has a very central position, and in particular so-called distributed production, where thermal energy is produced at the location of the end customers, and not in dedicated solar heat collector farms. Solar heat collectors are integrated into the buildings where the energy will be used, instead of occupying large land areas. The goal is to reduce the operational cost connected to energy loss, and at the same time make the systems “greener” without incurring large initial capital investments.

"RELaTED can be an important trigger for further development within building integrated solar heat collectors in combination with low temperature district heating networks” said a representative from Beoelektrane.


The project is expected to gather a lot of interest and international attention, in particular in the European market.We hope to be able to demonstrate good practice for future projects within our district heating network”, said Ljubisa Vladic, Deputy of Production and Distribution Manager at PUC Beogradske Elektrane.

Read more about the RELaTED project at

Inaventa Solar AS

Pustutveien 18
N-1396 Billingstad

+47 485 00 588
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