Off-grid buildings are those that are self-sufficient in energy and don’t need a grid connection. They are almost always private homes, which makes Fluid Solar House in Adelaide a notable example: it’s a unique off-grid office building, a world first for its type.
Fluid Solar is a company that specialises in affordable clean energy and efficient modular housing. It made sense to create a headquarters that embodied their core principles, and at the same time it offered an opportunity to road-test some pioneering ideas. Off-grid buildings are rare at this scale, and a flagship HQ would demonstrate the viability of their technologies. The building opened earlier this year, ran for a month on the grid while everything was tested, and then shut off the connection.
The most distinctive feature of Fluid Solar’s building is that it uses a hybrid energy system that combines solar PV and thermal. The roof has a 150Kw solar thermal collector array, with heat stored in a large thermal bank in the underground car park.
This thermal bank is basically a lined and insulated underground pit filled with water and gravel, and it can hold heat for months. It runs the whole building’s heating needs, and it also handles the cooling. An air conditioning system that runs off hot water is counter-intuitive, I realise. It involves something called a solar thermal absorption chiller, and you can read up on it here. Given the growing use of air conditioning around the world, it’s a really important technology.
The rest of the roof is given over to PV, and as you can see from the cutaway above, the roof is constructed at the optimum angle for sunlight. 90% of the energy storage is thermal, but there’s a bank of extra batteries for good measure. On sunny days, excess energy can be collected and driven away through the 11 electric car charging points in the car park.
As buildings go, Fluid Solar House is not the most attractive, but it’s packed with innovative passive and renewable energy technologies. Feel free to geek out on the technical details here.