HYPP – the development of semi-transparent photovoltaic modules for building-integrated hybrid systems that make complementary use of sunlight for photosynthesis and photovoltaics
The objective of the HYPP project is to operate photosynthesis and photovoltaics using one and the same module. It involves development of a solar cell that allows the light wavelengths required for photosynthesis to pass through and yet absorbs as many of the others as possible. There are many options for using such a hybrid module, ranging from energy-producing building facades to greenhouses.
Plants only require certain parts of the light spectrum for photosynthesis. If we wish to make optimum use of sunlight in parallel with energy production we can use the remaining wavelengths to generate electricity through transparent solar cells. The HYPP research project therefore involves developing a hybrid system that couples a bioreactor with a photovoltaic module. There is a broad range of possible uses, from greenhouses to integration in the building envelope of residential buildings. The latter would allow building facades to produce electricity, heat and biomass efficiently on the same surface. The system could also be connected with wastewater treatment facilities for recycling nutrients and water.
In this project, funded by the Future Building research initiative, a market-ready bioreactor developed by project partner SSC is being used where microalgae swim in water between two internal glass panels, producing heat and biomass. The noble gas argon provides the heat insulation behind the two outer panels. Thin photovoltaic coatings can be applied directly to a glass surface. The solar power drives the bioreactor's pumps.
The Institute of Networked Energy Systems is developing a semi-transparent photovoltaic coating for this project. Solar cells developed at the Institute with an ultra-thin layer of germanium are particularly suitable for this. By combining the materials in an optimal manner the coating is made as penetrable as possible in the light spectrum plants can use between 650 and 710 and at around 430 to 450 nanometres. On the other hand, the sunlight for the remaining wavelength areas is absorbed as much as possible, in order to produce energy. To achieve a high energy yield, the solar cell is structured in such a way that light from certain wavelengths is reflected multiple times within the layers and thereby passes through the absorber multiple times. Yet sunlight from the rest of the spectrum simply passes through. This not only maximises the build-up of biomass: it is also possible to control the production of fats and pigments in the algae via the wavelength.
April 2017 until August 2019
The Future Building research initiative by the Federal Institute for Research on Building, Urban Affairs and Spatial Development
SSC Strategic Science Consult GmbH
Institute of Networked Energy Systems
Project Manager at the Institute of Networked Energy Systems
Dr. Martin Vehse