Energy-positive commercial building with DualSun panels – Lyon (FR)

KTR is the first commercial building renovated to be energy-positive with thermal and electric energy storage. Marc Campesi is head of the engineering firm that designed the project. His company was selected for the global renovation project, and following the installation, we got to ask him a few questions.

Please present yourself

I’m a highly engaged participant for sustainable cities. I’m a professional who believes that it is possible to combine human and economic development with respect for the environment. I design and realize living and working spaces for more than 20 years. My clients are private companies, industrial groups, and organizations that are looking to renovate or build their offices with an eco-responsable approach. I am located between Lyon and Paris with a multi-disciplinary team that includes engineers, architects, interior-designers, ergonomic specialists, and landscapers in order to offer my clients quality turnkey services.

Can you explain the history of this project ?

The KTR group is a world leader in mechanical transmission. In 2017, KTR France purchased a 900m2 building just outside of Lyon with the plan to move its headquarters. As the building dates from the 1970s, this acquisition was a real opportunity for Pierre Martin, CEO of KTR France, to concretely pursue an eco-responsable approach for the company.
The global renovation project presented to KTR France by Diagonale Concept includes a strong capacity of innovation on the part of KTR. This unique project is an energy-positive renovation project. The building is already going towards energy-independence over the past months, thanks to self-consumption of the electricity and geothermal energy storage at over 150 meters in depth.
How is the DualSun installation used in the the global energy system?
The installation of DualSun panels is a central part of the energy system: the electricity generated is used in the building and to power the heat pumps, the heat generated in the summer and inter-season months is stored underground for use in the winter months.

Why install DualSun solar panels ?

The double production of the DualSun panels particularly interested me. Above 25°C, the electrical efficiency of traditional photovoltaic panels slowly decreases. The presence of a water circulating behind the PV panels allows to cool the cells in the hot summer months and increase their efficiency, and simultaneously produce a large quantity of solar hot water. This solar heat is transferred to geothermal storage 150m underground.

How did you discover DualSun ?

I discovered DualSun by the eOspace Lyon club, which unites local actors involved in sustainable cities. The Swiss engineering firm Amstein&Walthert which is located in Lyon is very active with the club and collaborated with Diagonale Concepte for the KTR project. Amstein&Walthert is at the origin of the 2SOL concept which integrates the DualSun technology to produce solar energy which is stored in geothermal storage.

How did the installation go ?

The panels are relatively simple to install. Setting the correct parameters requires experienced professionals with the support of DualSun. The only difficulty is that the installation requires two experts, for the photovoltaic component, and for the thermal component. Innovation is never entirely smooth from the get-go, but overall, the installation process went very well.

Would you recommend DualSun ?

Yes. Even the installation has only been operational for several weeks. I really appreciated the technical support and presence of DualSun during the installation process. The building is connected and in several months, the first results will demonstrate the measured performance of the DualSun panels.