PVT Nexus Research Network: bridge the gap between academia and practice

The PVT international research community is receiving support from Northern Europe. MG Sustainable Engineering from Sweden officially launched the PVT Nexus Research Network at the end of August. To kick things off, a one-day online conference was held on 27 August, at which a number of experts from IEA SHC Task 73 on PVT Heating Systems gave presentations sharing insights about market development and PVT reference cases. You find the recording of the conference here and the presentations for download here.

Maryam Shalaby from MG Sustainable Engineering introduced the PVT Nexus during the conference as a “Research Network for PVT technologies and systems” launched within the EU project PVT4EU. She listed different benefits that members will have from the network. “We offer internship opportunities within the network aiming to bridge the gap between academia and practice. Then we aim to encourage all network members to collaborate on ongoing projects, as well as work together on joined proposals to apply for funding from different EU Programmes”. Shalaby also highlighted that the network will help to expend the professional profile of its members through integration into international scientific networks.

“Task 73 participants can benefit greatly from the PVT Nexus Research Network and vice versa,” confirmed Dr María Herrando, Project Coordinator at the Spanish Institute ITA – Instituto Tecnológico de Aragón. “The network offers a platform to develop new proposals, launch collaborative projects, and most importantly, it helps to connect people to accelerate the deployment of PVT installations.”

Dr. Herrando co-leads the Modelling and Monitoring working group within Task 73, alongside Dr. Raquel Simón, R&D Engineer from Endef Solar Solutions, a Spanish PVT manufacturer. Both have also taken on mentorship roles within the PVT Nexus Research Network, supporting, for example, early-career researchers and PhD students in their work on PVT.

“The network complements the goals of Task 73 by encouraging interdisciplinary collaboration, offering targeted workshops, and bringing together researchers and industry stakeholders to overcome market barriers,” summarized Iván Acosta Pazmiño, Head of Engineering at MG Sustainable Engineering, following the successful launch of the network.

In the following sections, we take a closer look at the contributions made by Task 73 researchers during the online conference held at the end of August.

A look at the real market situation of PVT

Simón from Endef highlighted the significant amount of ongoing research in the field of PVT technology. According to her, a search on ScienceDirect yielded 12,157 research articles and reviews on the topic in 2024. Despite this extensive research activity, the market volume for PVT systems remains relatively small.

She pointed to several key factors contributing to the slow market development, including a lack of long-term reliability studies and low awareness among both the general public and installers. “It’s not easy to find an installer who can handle both the electrical and thermal aspects,” Simón noted. She also observed that many subsidy programmes exclude PVT collectors, instead supporting only photovoltaic or solar thermal technologies individually. This makes it difficult for PVT systems to compete with these subsidized alternatives.

Regarding the cost-effectiveness of PVT installations, Simón presented an estimated cost breakdown for a residential system. The data showed that PVT collectors account for less than 50% of the total system cost.

Figure 1: Estimated cost breakdown of a residential PVT system Source: Endef Solar Solutions

Recommendations for integration and control strategies

Qian Wang, Senior Researcher at the KTH Royal Institute of Technology in Sweden, presented the Swedish project DoubleUp, which will contribute to Task 73 on PVT for air heating. DoubleUp explores the dual benefits of combining PVT technology with thermal storage and HVAC systems, compared to standalone PV solutions.

“The real estate company Einar Mattsson is a partner in DoubleUp and is providing a modern student dormitory for a PVT air heating demonstrator,” Wang explained. The KTH team will develop and model various integration strategies for incorporating PVT air collectors into the building’s existing HVAC system. The apartment block, which consists of 100 small student flats, is currently heated via an air ventilation system connected to a ground-source heat pump with boreholes. The heat generated by the PVT air collectors can therefore be utilized in several ways: for domestic hot water, for recharging the boreholes, or for space heating via ventilation.

Installation of the PVT system is planned for 2026, after which it will be monitored as part of the DoubleUp project. “Our goal is to develop practical recommendations for the construction and HVAC sectors on how PVT systems should be integrated and controlled under Swedish climate conditions,” Wang added. The Einar Mattsson demonstrator will be one of several PVT air heating case studies to be documented and analyzed in detail within Task 73.

PVT produces six times more energy than PV

Dualsun is another PVT manufacturer that is heavily involved in Task 73. Marcus Kanewoff, CEO from Dualsun Nordic, represented the French PVT producer during the online conference. He presented a compelling visual – a pyramid – demonstrating how PVT panels can harness up to six times more energy from a rooftop compared to conventional PV panels alone. The green part of the pyramid stands for the energy from the surrounding air that can be used via the large heat exchanger surface at the back of many PVT elements.

Illustration of the multiple energy sources utilised by PVT collectors Source: Dualsun

This high yield from PVT collectors throughout the year can only be achieved, if the use of PVT heat is ensured during the summer months. In Sweden, where heat pump systems are often paired with geothermal boreholes, the heat from PVT collectors in summer can be used to regenerate the ground, enhancing the year-round efficiency of the system.

One notable example is the Heinöhem district on the Swedish island of Höno, which has undergone a 22-year energy transition. The district, now heated by brine-based heat pumps, uses boreholes and rooftop PVT collectors installed on the central heating facility as the heat source. A local district heating network supplies heat to 48 row houses and 46 apartments.

According to the energy contractor Enwell, oil consumption in the district is now virtually zero. The 94 Dualsun Spring 375 PVT panels (each 1.88 m²) installed at the site produce an average of approximately 160,000 kWh per year. This translates to around 907 kWh/m² annually – five times more than the solar electricity output alone, which was measured at 171 kWh/m²/year. “The PVT collectors in the Nordics contribute heat from early spring until late autumn due to utilising the surrounding air without the risk of stagnation in the solar circuit”, explained Kanewoff the advantages.

A video by Enwell also notes that the ground temperature in the boreholes has increased by 3°C due to summer regeneration, reducing the electricity consumption of the heat pumps by approximately 10%. “Heinöhem is a great example of a successful energy transition over 20 years from building energy class G to B,” summarized Kanewoff.

Heating center of the Swedish Heinöhem district with 94 Dualsun PVT panels on the roof installed in 2021 taken from the YouTube video of the contractor Enwell Source: https://www.youtube.com/watch?v=ormaW8HHJns

Websites of organisations mentioned in this news article:
Task 73 PVT Heating Systems: https://task73.iea-shc.org/
Institute ITA – Instituto Tecnológico de Aragón: https://www.ita.es/
Endef Solar Solutions: https://endef.com/en/
KTH Royal Institute of Technology: https://www.kth.se/en
Dualsun: https://dualsun.com/en/
Enwell: https://enwell.se/