Making use of Belgium's digital electricity meters with my-PV

A 4-person household in Flanders, Belgium, has had a photovoltaic system since the beginning of 2021; a total of 7.9 kWp is distributed over the two roof areas of the house, an 8.5 kWh battery storage completes the investment.

Based on rising energy prices and the meanwhile expensive water heating with gas, the owner of the 200 m² single-family house came up with the idea to search for alternatives on the internet. There are different brands, but my-PV's AC•THOR was the only brand compatible with the P1 interface of the S211 or T211-D digital meter. This is an exclusion criterion for customers in Belgium due to the regulations regarding digital electricity meters. However, the products from my-PV fulfill this compatibility with a small additional gadget, the specially developed P1 interface.

The advantage of AC•THOR?

“We wanted to do more with the surplus electricity during the summer months, to use more of it ourselves. Then it occurred to us that the central heating needs gas to heat the water, while we – especially during the summer – feed a lot of excess electricity into the public grid,” John Michale, the homeowner, explains the considerations. "We wanted to save this gas and use the electricity from the photovoltaic system on the roof to heat the hot water in the future."

The entire system consists of two boilers connected in series. The 150 liter boiler is the central tank that is supplied with 200 liters of hot water, which is mainly heated by excess photovoltaic electricity in the summer months. From the largest 200 liter boiler, heated to +/- 70°C by AC•THOR, the water is piped to the other 150 liter boiler, heated to 55°C by the central heating, so there is always at least 55 °C warm water is available.

Due to the battery storage, the system works great between April and October. In the months with less sun, the hot water has to be heated conventionally due to the battery storage and the settings made there, since there is not enough photovoltaic surplus for the battery and hot water preparation.

Customer opinion

"Try it out!! It is very interesting that my hot water system with the AC•THOR consists of only three components: the inverter itself, the temperature sensor and the P1 interface. So you don't need to calibrate a complex connection!"

More information and details about the project in Belgium can be found here.