For AC off-grid systems with frequency-shifting battery inverters, the photovoltaic power manager AC•THOR has now replaced the AC ELWA-F in the product portfolio.

Description

The newly built Seethalerhütte is located at nearly 3,000 meters above sea level and is operated by the Austria Section of the Austrian Alpine Club. It provides accommodation and gastronomy services. An 11.55 kWp photovoltaic system and a combined heat and power (CHP) unit supply the building with electricity and heat.

The battery storage system has a nominal capacity of 52.8 kWh. Once this is depleted, any additional surplus energy is used by the two AC ELWA-F units for heat generation before the PV system shuts down.

Why Hybrid Storage?

Under favorable sunlight conditions, typical battery storage systems can reach full charge as early as mid-morning. From that point on, excess energy in PV off-grid systems usually remains unused. The hybrid storage concept offers an innovative and cost-effective way to expand existing storage capacities while significantly increasing the utilization rate of PV off-grid systems. Generating heat with solar power becomes an efficient method to make use of surplus energy.

The cost of these additional capacities is incomparable to the current prices of battery storage. Investing in the my-PV solution requires only a minimal financial effort in comparison!

Functionality

Our product is specifically designed for operation with frequency-shift battery inverters. When used with compatible devices, the power controller detects available surplus energy through the AC grid. These inverters increase the frequency in the local AC grid once the battery is fully charged. The purpose of this is to signal the PV inverter to reduce power output, preventing battery overcharging.

my-PV detects this frequency increase and starts heating before the PV inverter shuts down. By continuously adjusting power to match the available surplus, only the excess energy is used for heating, preventing unnecessary battery discharge. Otherwise, once the battery is fully charged, the available solar energy would remain unused.

The Hybrid Storage Concept

In the chronological sequence of the hybrid storage concept, current loads take priority, followed by battery charging, and only after that, any remaining surplus energy is used for heating.

When implementing such systems, it is crucial that the battery always has a higher priority than heating during the charging process. This operational approach is recommended because electrical energy holds a higher technical and economic value than heat.

System Diagram

For this application, the AC•THOR has now replaced the AC ELWA-F in the product portfolio. It is powered, like any other load, via a standard socket. No additional wiring is required.

This is true "Plug-and-Play": Simply plug it in, and you're done! No additional wiring for communication is necessary!

Compatible Battery Inverters

The list of manufacturers capable of controlling the AC•THOR is continuously growing. Current information on this can be found under the compatible manufacturers section.

Product Details AC•THOR

• Nominal Voltage 230 V

• Power Regulation 0 – 3,000 W, stepless

• Network Connection Single-phase, protective contact plug

• Load Connection Protective contact socket for resistive loads

• Display Colour graphic, touch screen 2.83“

• Connection Cable 2.8 m

• Dimensions 135 x 210 x 65 mm

• For Frequency-Shift Battery Inverters 230 V, 50 Hz