Austria-based my-PV has developed the alternating current model AC ELWA-E specially for smart home systems with integrated battery storage. The heating element is infinitely variable from 0 to 3,000 watts, adjusts its output to the power surplus once a second, and thus reacts very quickly. AC ELWA-E is integrated into the facility management system via Ethernet and has a standby consumption of less than 1.5 watts.
SMA-employee Manuel März was the beta-tester for this particularly flexible energy supply for one-family homes. A grid-connected photovoltaic unit with connected battery storage has been supplying his house in Borken with power since 2014. The building is heated using an air-to-water heat pump. In spring 2016 März upgraded the system to include an AC ELWA-E developed by my-PV.
Hybrid storage maximises self-consumption
The complex system is controlled by an SMA Sunny Home Manager. The photovoltaic plant first covers the current own power requirement and then charges the battery. The rest of the solar power then heats water for the heating system via the AC ELWA-E. Now that the photovoltaic unit not only supplies the house with electricity but also with heat, the heat pump is only used to generate energy as a last resort.
Thanks to the AC ELWA-E I was able to deactivate my heat pump completely during the summer months. That means a longer service life for such sensitive technology, is how März describes the advantages of the new system. Dr Gerhard Rimpler, CEO of my-PV GmbH, sees the advantage of AC ELWA-E over an auxiliary battery storage especially in terms of price. The cost of AC ELWA-E as additional storage capacity is nothing compared to the present cost of batteries, he says. On top of that, an existing system can be expanded with little extra effort.