From pv magazine Germany
Germany’s Paxos has partnered with the TH Köln University of Applied Sciences to develop a solar roof tile that could be used to generate electricity and heat at the same time.
The photovoltaic-thermal (PVT) tile’s appearance barely differs from conventional roof tiles, which could make them attractive for homeowners. Paxos and TH Köln fabricated a tile prototype to test its temperature, walkability, high resistance to environmental influences, and safety. They also analyzed the glass to minimize optical losses through reflection or scattering.
They tested the prototype in a testing facility equipped with microinverters and an air heat pump.
“Thanks to the adjustments we made to the actual roof tile, the physical properties and also the energy yield have been significantly improved. The system was thus ready for continuous use under real conditions,” explained Christian Dick, project manager at TH Köln.
Image: Costa Belibasakis/TH Köln
Performance tests started under real conditions in October. The system shows comparable values in terms of electrical performance as a reference system with conventional, elevated solar modules.
“An air duct for cooling the solar cells was integrated into the solar roof tile, which improves the working point, just like the rear ventilation in conventional systems,” Dick said. “Our data shows that correspondingly comparable electrical performance is to be expected. According to him, initial data also showed an increase in the coefficient of performance of the heat pump by around a quarter, depending on the heat requirement and the prevailing weather conditions.
TH Köln said the results show that the solar roof tile can also make a contribution to the heating supply of a building, increasing the overall efficiency of the system.
“Many roof areas in Germany are not used to generate energy – this would be an important building block for the success of the energy transition,” said Julian Münzberg, a project manager at Paxos. “We would like to create an offer for the listed building and for people who have previously avoided solar because of the optics.”
Paxos has already sold the patents for the solar roof tile to an undisclosed photovoltaic manufacturer. It will take over series production. Paxos is also behind the PV roof tile that Meyer Burger will sell and is currently putting it into series production.
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Set it up so that, when the solar panels are covered with ice and / or snow, you can back-feed some heat into the panels, such that they shed the ice / snow and get back to generating power ASAP. Germany isn’t the only place that gets plenty of ice and snow on the roof.
Find a way to tie the heat pump into the building’s hot water supply. Many buildings need hot water year round but only need hot air for part of the year. They make hybrid hot water heaters which pull heat out of the surrounding air to heat the water; that’s just a heat pump mechanism. Is it really so hard to make a hot water heater that ties into an existing heat pump system?