Excess PV power to activate floor heating in commercial buildings

Austrian solar company my-PV has designed a new rooftop PV solution that enables thermal concrete-core activation in commercial buildings.

The special configuration of the proposed solution, according to the company, is able to convey surplus electricity generated by the rooftop array to an electric underfloor heating system which, in turn, transfers the energy to the foundation concrete.

“Due to its high mass density, concrete is an excellent heat storage [resource],” said my-PV managing director Gerhard Rimpler, noting that the solid construction element absorbs heat and releases it again with a time delay. “This way, solar energy is only converted into heat where it is needed, directly in the floor,” he further explained.

This approach is being tested by the company at its new headquarters, under construction in Sierning, Upper Austria, which will also host a 100 kW PV system deployed on the rooftop and a facade, and which has a building surface of 858m². “It goes without saying that we are also proceeding completely according to our guiding principle of ‘cables instead of pipes,’ for our new company headquarters,” Rimpler stated.

Around 40 kW of electric heating wires have already been cast into 25cm to 50cm thick concrete. “The heating load of the low-energy house constructed with lightweight timber is significantly lower than 40 kW, but the excess energy can be temporarily stored by the construction element activation and released again later,” the company specified.

The proposed solution, which was tested through a series of simulations, is claimed to help reduce the building’s annual costs for water and power by around 67%, compared to standard heating. “The house of the future is solar-electric. This now also applies to heating in corporate buildings,” Rimpler affirmed.