Photovoltaic hybrid boilers by fothermo

The photovoltaic hybrid boiler by fothermo can reduce your hot water costs by up to 100%. It uses primarily the energy of the sun. On cloudy days, additional heating can be provided automatically via the socket.

Characteristics

• 75% energy saving: A 2-4-person household can use an 80-liter photovoltaic boiler to obtain around 75% of the energy required for hot water preparation from the photovoltaic modules. The remaining energy is drawn from the grid, especially in the winter months. With economical hot water consumption, up to 100% of the requirement can be covered by the photovoltaic modules.
• 1500W electric post-heater: The powerful electric after-heating via the 230 V power network enables sufficient hot water to be produced even on cloudy and dark days. Once the boiler has completely cooled down or has been emptied, the water temperature can be heated back up to a high temperature within a short time.
• Digital display on the boiler: An LC display provides information about the system, such as: B. the water temperature, the power and the energy already used.
• Plug and play: The photovoltaic modules are simply connected using the MC4 plug connections. Since the entire system works in extra-low voltage, no electrician is required for its assembly and commissioning.
• Direct current use: Direct use of the direct current from the photovoltaic modules to heat the water. No inverter or battery is required for operation. This enables very easy commissioning and reduces costs and complexity of installation and operation.
• Warranty: 3-year manufacturer's warranty

 

Photovoltaic hybrid boiler at a glance – how it works

The photovoltaic hybrid boiler is the ideal solution for a cost-effective and sustainable hot water supply in your home. Hot water usually accounts for around 20 - 40% of the energy consumption in a household. Fothermo boilers are the easiest way to use the sun's energy directly.

With 550Wp from solar panels, the photovoltaic hybrid boiler heats the water using photovoltaic power. In order to have sufficient water available even on cloudy days, up to 2000Wp of photovoltaic power can be connected and/or the intelligent 230V auxiliary heating can be used.

The boilers are available in 30-liters and 80-liters sizes. The boiler is mounted on a load-bearing wall using two screws. A corresponding mounting device is already mounted on each boiler. A pressure relief and check valve are also included in the delivery. The water connection is made via two 1/2-inch connections with external thread.

 

1500W heating & assembly

If the sun does not provide enough energy to heat the water for a longer period of time, the boiler can be automatically reheated using the 230V reheating system. To activate the reheating system, the boiler's thermostat is set to a minimum temperature, for example, 35°C. As soon as the water temperature falls below the set minimum temperature, the water is reheated using 1500W electricity from the mains. The reheating process ends automatically as soon as the water has reached the set minimum temperature again. 

The maximum water temperature of the boiler is 65°C. When the 30-liters boiler is fully heated, around 72 liters of 34°C water can be taken from it, for example for showering. The 80-liters boiler delivers around 180 liters of 34°C hot water. The installation of the photovoltaic modules is very easy thanks to plug & play connections. The solar panels are connected directly to the boiler via the MC4 plugs. An extension cable can optionally be used for longer distances between the photovoltaic modules and the boiler.

 

Hybrid boiler without grid feed-in

In the connection plan without grid feed-in, the photovoltaic modules are connected to the photovoltaic hybrid boiler. The heating process begins immediately after the photovoltaic modules are connected. Two or more photovoltaic modules can be connected in parallel. An extension cable connects the photovoltaic modules to the boiler. If the output of the photovoltaic modules exceeds the output of the boiler, the boiler regulates the maximum output of the modules down. Since the entire system operates at extra-low voltage, no electrician is required for installation.

 

Hybrid boiler with 800W micro-inverrter and mains feed

When permitted by the local regulations, the excess photovoltaic power can be fed into the house grid via an 800W micro-inverter. The fothermo switching device is required as an energy manager for this. The switching device detects when the photovoltaic hybrid boiler has finished heating or when more photovoltaic power is available than the boiler can convert into heat. In these cases, the excess energy is fed into the house circuit. On particularly sunny days, the switching device starts feeding in partial surplus power from 1 - 2 modules early in the morning. This ensures that the house's basic electrical load is covered in the morning hours. This means you save not only on hot water costs but also on electricity costs.

 

Calculation of profitability

The classic 80-liters electric boiler is usually the largest consumer of electrical energy in the household. It generally consumes around 3,5 kWh of electricity per day. This corresponds to around 1277 kWh of electricity per year. With average electricity prices in Germany of €0,31/kWh, the annual cost of producing hot water is €396,02.

The photovoltaic boiler gets its energy primarily from the sun. For example, if three photovoltaic modules with 430Wp each (1,29 kWp total photovoltaic output) are connected to a boiler, these photovoltaic modules generate around 1200 kWh per year in Germany. A large part of the electricity generated can be stored in the hot water. On cloudy days, electricity must be drawn from the grid to heat the water.

 The photovoltaic hybrid boiler can generally reduce hot water costs by around 75%. This corresponds to around €300 per year.

You may see all the Fothermo products here.