Multi Flow Technology Energy flow management

Intelligent management of energy flows

Storing solar energy and being able to use it around the clock is one thing – efficiently combining the output from a photovoltaic system, energy storage system and additional power sources is quite another. This is where Multi Flow Technology from Fronius comes in, providing intelligent energy control for maximum self-consumption rates and optimum utilisation of the storage system.

Advantages of Multi Flow Technology

Conventional inverters only allow one energy flow at a time; simultaneous current flows are not possible. This means the energy generated is not used optimally. Fronius inverters with Multi Flow Technology can control different energy flows in parallel and in all directions. This has many advantages.

Maximum efficiency with DC-coupled batteries
DC and AC coupling: integration into an existing PV system
Reliable power supply even during a power failure
Control of battery charging and battery usage

The energy flows in an energy storage system

Photovoltaic generator

The PV generator can supply loads in the household and charge the battery at the same time. If there is a surplus, it can be fed into the grid.

Loads

Loads in the household can be supplied by the PV generator and the battery at the same time.

Battery

If there is a surplus, loads are supplied and the battery is charged in parallel. When there is a consumption situation, power is supplied by the PV generator and the battery.

Additional AC source

The inverter can use energy from an additional AC source to charge batteries, for example, from wind turbines or existing PV systems.

Inverter

The inverter controls the energy flows in the storage system.

High self-consumption rate through simultaneous energy flows

Multi Flow Technology allows simultaneous energy flows in all directions, which means less grid usage and less feed-in – i.e. lower costs and a higher yield.

In this application, for example, a Fronius Symo GEN24 6.0 Plus with PV production of 6 kW can supply the household with 3 kW and at the same time use the other 3 kW to charge the battery*.

*possible with BYD Battery-Box Premium HVS/HVM

Reliable power supply even during a power failure

In backup power mode, for instance during a power failure, Multi Flow Technology provides a backup power supply from the PV system and the battery. The PV system can supply the household with solar energy even if the battery is already discharged.

In this application example, in the event of a power failure, the loads in the household are supplied with power and the battery is charged at the same time*.

*possible with BYD Battery-Box Premium HVS/HVM

Expanding the PV system to include a storage unit and a hybrid inverter

Owners of a PV system without a storage unit can retrofit their PV system with one and use the advantages of the Multi Flow Technology for their own benefit.

In this application example, when there is a surplus (green line), the loads in the household are supplied with power and the battery is charged at the same time. When there is a consumption situation (blue line), power is supplied by the PV generator and the battery.

Enlargement of the PV system with AC coupling

Multi Flow Technology allows both DC and AC coupling of the storage system. It is therefore possible not only to integrate the storage solution into existing PV systems, but also to incorporate small wind generators or mini-cogeneration units into the storage system.

In this application example, when there is a surplus (green line), the loads in the household are supplied with power and the battery is charged from the DC and the AC side. When there is a consumption situation (blue line), power is supplied by the DC and AC-side PV generator and the battery

Fronius comes in top for fifth time

Fronius GEN24 Plus and BYD Battery-Box Premium: this combination has once again achieved top rankings at the Energy Storage Inspection 2024. The Energy Storage Inspection is carried out annually by HTW Berlin and is considered Europe’s most important study on the efficiency of PV storage systems. As part of this inspection, the duo made a great impression for the fifth time in a row thanks to their exceptional efficiency.

Find out more about the energy storage device inspection

The AC charging function: Even more flexibility for the storage system

Inverters with Multi Flow Technology can draw an AC charging current from additional energy sources or the grid, in parallel with other energy paths. This means the inverters are capable of performing many additional functions:

Coupling with other energy sources

Alternative energy sources such as micro-cogeneration units or wind turbines can be connected to the photovoltaic system via the AC charging function. System owners can temporarily store excess energy from these complementary sources in the battery. This ensures a reliable energy supply, even during periods when the PV system is only supplying small amounts of solar energy – in winter for example.

Using time-dependent electricity tariffs

More and more electricity suppliers are delivering electricity to customers according to timedependent tariffs. Via the AC charging function, system owners can charge their energy storage unit from the grid during low-tariff periods (if permitted), then supply the household via the battery during high-tariff periods.

Minimum charge for backup power situations

The AC charging function ensures that the battery always retains a certain minimum charge, which can be made available during a power failure. If a grid shutdown is announced, system owners can fully charge their storage units in good time thanks to the backup power function.

Conservation charge

If little or no solar energy is available over a prolonged period – for example, if the photovoltaic system develops a fault – the AC charging function kicks in to prevent deep discharge of the battery and so extend the battery service life.

Improving grid quality

Photovoltaic storage systems with an AC charging function make an active contribution to improving grid quality, as during periods of high feed-in, loads can charge their storage systems and thus relieve pressure on grids.

Storage & energy management with Fronius

Multi Flow Technology in action: learn all about Fronius hybrid inverters, comprising the SnapINverter and the GEN24 Plus product series, combined with battery storage units from BYD and LG Chem. Our experts will show you how heating and cooling become part of the overall solar energy system through energy management, and also present intelligent solutions for charging electric vehicles. Watch the video

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