Energy self-sufficiency with E3/DC storage
An apartment block with E3/DC storage
In Wetzikon in the Swiss canton of Zurich, the dream of energy self-sufficiency has become reality for the owners and tenants in an exciting block of flats. The Quattroporte storage system from E3/DC plays a decisive role.
In SonnenparkPLUS, an ecological new construction project, ten residential units on five floors make up an energy reference area of 1,705 m2. The planners wanted to create a residential building that supplies its residents with their own solar energy around the clock, not only for electricity, but also for heat and e-mobility.
Energy house
The project was planned and executed by arento ag from nearby Hinwil. Architect Franz Schnider is a member of the company's management and is enthusiastic about energy houses. He describes their approach as follows: "First and foremost, we try to use as little energy as possible. We have a top building envelope, use highly efficient heating and ventilation systems and educate customers on energy consumption. The other piece of the puzzle is efficient solar power generation."
Off grid
The specifications aimed for full electric self-sufficiency. As planner, Martin Brawand from the energy technology company Windgate was faced with the not-so-easy task of creating sufficient generation capacity: "If the architect is planning a zero- or plus-energy house, we have to get to the point where we can at least cover the building's needs with the photovoltaic system." The simulations calculated in advance quickly showed: the potential of the roof area with 44.55 kWp would not be sufficient.
So the planners turned their attention to the two façades facing the sun and achieved a further 37.08 kWp by using the south and west façades. With the total capacity of 81.63 kWp, the first step had been achieved: the building will certainly generate more energy over the year than its occupants need, so it can be considered a PlusEnergy house. As advantages of the façade PV, the planners cite on the one hand its multifunctionality as a power generator and durable building envelope, and on the other its vertical surface, which can be adapted to the lowest point of the building.
Big storage
With ten flats, if the electricity storage system is to do much towards self-sufficiency, one leaves the usual capacity range of domestic power plants. An E3/DC storage system from the Quattroporte series with 78 kWh storage capacity is installed in the SonnenparkPLUS. The high capacity of the Quattroporte LINEA ensures self-sufficient supply throughout the night, reports Franz Schnider. Since commissioning, the apartment building has been practically self-sufficient, and even with winter the planners expect a degree of self-sufficiency of 63 % over the year.
All this is possible because the energy management system controls the entire building technology in a solar-optimised way: first, the solar power is used directly in the house, for heat generation and for ventilation. Of course, the storage tank is always charged in time so that self-sufficiency continues after sunset. Only then is the power fed into the grid, naturally with relatively high surpluses in summer.
But there is even more to sector coupling in the apartment building: the planners have provided four 22 kW charging stations for electric cars in the underground car park, which can also be operated with solar power via the energy management system.
The house planners took special care with the internal billing system, because despite all the sense of community, each household should only pay for its specific needs for electricity, heat and e-mobility. In all this, the grid operator in Wetzikon has almost become an "outsider": The household only needs one metering point in the house connection for feeding in surpluses and drawing residual electricity from the grid. Solar self-sufficiency in households: In Switzerland, it's easy!
Project: SonnenparkPLUS
Site: Wetzikon, Switzerland
External partners:
- Implementation: arento ag
- Planners: Windgate
Products & solutions: Quattroporte LINEA, 22 kW charging stations
