Colour solar collectors without losing efficiency

Architects and designers have long requested a wider choice of colours for solar collectors to allow them to blend into a building´s roof or facade. The acceptance of solar energy systems as integrated elements of the building’s envelope is mainly limited by aesthetic considerations, and one aspect of importance is the colour of panels. Coloured solar collectors can be found on the market today, but the problem is that they are far from as effective as the black ones. This situation challenged the group behind the Wabaselcoat project, which has been running for a year now.

Wabaselcoat (WAter BAsed SELective COATings for intelligent façade collectors) is a R&D project within the M-ERA.NET program, an EU funded network which has been established to support and increase the coordination of European research programmes and related funding in materials science and engineering. Partners in the project are National Institut of Chemistry-Ljubljana (NIC), Chemcolor, FOSS and Aventa.

The goal of Wabaselcoat is to develop environmental friendly water based coatings (TISS-paint) in different colours that will keep, or even improve, the efficiency of the solar collector. The coatings will also have anti soiling effect and reduce dust and dirt on the collector surface. The first report on the results from the project activities is now published, and it looks very promising.

The results from the first year of activity are mainly related to experimental work on the paint, composition, application, aesthetics, efficiency, UV-resistance, durability etc. Based on a market study three different colour shadings were pre-selected, which should have the highest potential for acceptance by clients/customers in Europe. These colours have been tested on collector samples with very good results. In the next phase a wider colour range will be developed and tested in larger scale.


Aventa is participating in a new EU project – solar collectors in combination with district heating

A new Horizon 2020 project, RELaTED, that is focusing on heat delivery from solar collectors into district heating systems has been launched. The innovative aspect of the project is that the solar collectors are decentralized. Heat is produced where it is to be used and not in solar parks which require large land areas.

District heating (DH) systems are one of the most energy efficient heating systems in urban environments, with proven reliability within many decades already. DH systems are also  identified as a key to achieve the de-carbonization of heating energy in European Cities. Renewable and waste heat sources are foreseen at the same time as de-carbonized heat sources and the way to guarantee competitive energy costs with limited influence of fossil fuel supply price volatility. 

Traditionally, district heating plants are hierarchically organized with central energy production facilities delivering heat to a variety of distributed consumption locations. RELaTED will introduce an new concept in which a network of low-temperature energy sources / technologies (solar collectors, heat pumps) can be incorporated into a low-temperature district heating system. The goal is to reduce operating costs associated with heat loss and to make the systems greener without major investment costs.

The RELaTED concept will be demonstrated in five different district heating networks, both new and existing, in Denmark, Estonia, Serbia and Spain. The strategy is in many ways the same as for electrical smart grids, where end customers are both consumers and manufacturers (plus customers).

9 different nations are engaged in RELaTED and the project will last until 2021.

Aventa approved as a supplier to UNHCR

Aventa has received approval as a supplier to the UN High Commissioner for Refugees, UNHCR. First delivery contract has already been signed and 80 stand-alone solar collectors will be sent to a refugee camp in Uganda during Q1 2018. The solar collectors will supply hot water for hygiene purposes.

Aventa offers a self-circulating heating system (thermosyphon) for tap water based on polymer collectors. The system operates automatically without the need for electricity, pumps and control equipment, and it has a favorable price. The fact that the solar panels are made in polymeric materials means that there is no danger of corrosion and the low weight makes them easy to handle.

Representatives from UNHCR visited Aventa and our production facility in early October, and there has been a thorough review of both the product and the manufacturing process. Approval of Aventa as supplier and Thermosyphon collectors as a suitable product came during November. UNHCR has now established a collaboration between Aventa and EDILSIDER S.p.A Modular Housing. EDILSIDER is a contracted supplier to UNHCR on small prefabricated modular houses for refugee camps.


OPVT – Hybrid solar collector (PVT) in polymer materials

OPVT is a German R&D project, on which Aventa collaborates. The objective of the project is to develop a hybrid solar collector composed of an organic PV component and a polymeric solar thermal component for the cost competitive, renewable energy production of both heat and electricity. The collectors will be designed as building-integrated solar envelope modules in order to meet future energy scenarios, which are directed towards zero energy or plus energy buildings. Tomorrow’s building skins have to be transformed to multi-functional roofs and facades producing heat (cooling) and electric power. 

The OPVT project aims to develop a more efficient combination of PVT by using organic photovoltaic cells with a positive temperature coefficient for the efficiency, which will permit higher operating temperatures. The organic solar cells have physical properties favouring the combination with polymeric solar collectors. The new collector will introduce a significant improvement with regard to costs and performance compared to existing PVT-products of metal-based solar collectors and silicon-based solar cells. By applying new materials like organic solar cells combined with solar collectors of polymeric materials, a better fit is obtained between the combined output in terms of renewable electric and heat energy. Added values will be the design as building-integrated solar envelope modules, superior ecological life-cycle balance, lower weight, dimensional flexibility and expected lower cost of the produced energy for the end-user.

Fraunhofer ISE (Institute for Solar Energy Systems) initiated the OPVT project together with German industry partners. Aventa was invited to participate as producer of state of the art polymeric solar collectors. Fraunhofer ISE is Europe’s largest Solar Research Institute, world leading in the field of solar energy research, both within PV, ST and solar building research.

Solar collector installation in progress at Ilseng Prison

Statsbygg* is looking to utilize solar energy. This summer, the agency signed a contract with Aventa for the delivery of a new solar heating system to Hedmark prison, Ilseng Deparment, in Hamar. Installation of 270 square metres of solar collectors that will contribute to the supply of domestic hot water commenced this week. Roof tiles are removed from the south-facing roof of the barracks and replaced with solar collectors. The total heat store volume is 8 400 litres. According to schedule, the installation should be completed by mid- December.

Ilseng Prison has the capacity to house 86 low-risk prisoners. Most prisoners are serving short-term sentences.

* Statsbygg is the Norwegian government’s key advisor in construction and property affairs, building commissioner, property manager and property developer.


National Institute of Chemistry in Ljubljana showcased NorDan Solar at the 2016 MOS


The MOS is one of the largest and most important trade fair events in Slovenia with 1,500 exhibitors from 35 countries and more than 125,000 visitors. A new feature this year was the Crossroads of Science and Economy element, supported by the Ministry of Education, Science and Sports. This special part of the exhibition promoted cutting-edge technologies and new technological innovations and processes. The National Institute of Chemistry in Ljubljana was one of several scientific institutions present at the stand. The institute has developed a special type of color painting – TISS coatings – that will improve both the efficiency and aesthetics of solar collectors. The NorDan Solar concept with solar collectors integrated in traditional window frames was used to illustrate state-of-the-art solar collector solutions.

NorDan Solar is a new window-integrated solar collector concept where polymeric absorbers are integrated in standard window frames. When integrated in new or existing buildings, the NorDan solar collector replaces the cladding. This is both favorable for the architectural expression, and in terms of the limited use of materials compared to traditional façade-mounted solar collectors. However, the most prominent advantage with this new solar heating product is that it is embodied in a unit which carpenters and other skilled installers are familiar with handling at the building site.


AventaSolar solar collector undergoing testing for verification of expected lifespan


Aventa recently visited the German research institute for solar energy – Fraunhofer ISE, in Freiburg – where our solar collectors have been a part of the experimental set-up  for several years. The solar collectors are primarily undergoing accelerated aging tests, which will determine their lifespan under various conditions. Ad hoc testing of the collectors is also being carried as part of our product development programme. 

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Demonstration of Aventa Solar Technology in Copenhagen


Planning of pilot projects was on the agenda when the partners in the Nordic Built project “Active Roofs and Facades in Sustainable Renovation” met in Malmö recently. The goal is to show solutions for sustainable renovation that can be integrated in existing buildings, with regards to architecture, comfort and energy efficiency. The Aventa technology will be used at a demo-site at the Technological Institute near Copenhagen, and at a CO2 neutral kindergarten In Copenhagen.

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BioSol – 100% renewable heating


BioSol represents a new concept for heat transfer from a stove into a water-based heating system, which combines high efficiency and negligible risks. A solar system is directly coupled to the heating system. The energy demand for space heating and hot water preparation can thereby be 100% covered by renewable energy in terms of firewood and solar energy. 

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