Alexandre Voirol

Substituting fossil fuels with renewable energies will not be feasible without a notable expansion of seasonal energy storage. Seasonal thermal energy storages (STES) are expected to contribute significantly to this goal. The project SwissSTES systematically analyses STES potentials such as available and unused cavities, geothermal probe or pit storages and it develops novel STES technologies together with a systemic action and implementation plan for Switzerland. The highly interdisciplinary consortium brings together all relevant stakeholders from science, industry and society to promote the spread of STES in Switzerland. In this context, technical innovations but also social, legal and economic aspects play an important role. Furthermore, regional case studies pave the way for future pilot and demonstration projects throughout Switzerland.

The aim of the project is the development of a single covered PVT collector with high electrical and thermal efficiency and a self-securing overheating protection realised by absorber shifting. An aluminium roll-bond absorber is used as heat exchanger, which enables good thermal properties on one hand and smart integration of the overheating protection mechanism on the other. The development includes the construction of a prototype on a scale of 1:1, its performance measurement in the laboratory and an assessment of its behavior when exposed on the test roof of the institute.

Clean water, a reliable power supply and cooling systems for medicines and vaccines are not a given in many rural hospitals in Africa. To ensure better healthcare also in remote regions, the EU is supporting SophiA project, which relies on modular containers to produce drinking water, heat, cold and electricity using solar energy. SPF Institute for Solar Technology is part of the international team responsible for the solar technology, the Life Cycle Assessment of the SophiA systems as well as the energy management and control of the subsystems.

Off-grid locations, i.e. locations that are not connected to the public grid and are remote from major transport routes, are predestined for the use of local renewable energies such as solar energy, hydropower or wind power. In Switzerland, these locations include in particular alpine farms, mountain huts and mountain restaurants.

In this study commissioned by SwissEnergy, we have investigated the current energy supply situation of such sites and determined the technical possibilities for supplying them with renewable electricity and heat. In addition, we have looked at legal and economic aspects.

In the project HiPer-PVT we have developed a glazed (covered) PVT collector with a high electrical and a high thermal efficiency. Thanks to an overheating protection mechanism becoming effective at approximately 100 °C, this collector can be easily integrated into a thermal system. The concept of the overheating protection is that once the absorber reaches a predefined maximum temperature, it is brought into contact with the cover glass via a thermally activated lifting mechanism. This increases the heat losses and limits the stagnation temperature.