REFERENCE · PHOTOVOLTAICS · DISTRICT HEATING
Sunshine that heats water in a boiler house:Solar water heating in a boiler house — 50 kVA PV source, Brezno
PV energy drives the heating spirals, controlled by irradiance and temperature
Customer challenge
A boiler house consumes electricity for water heating and circulation all year round. The operator wanted to cover this in island (off-grid) mode from its own photovoltaics — from an own source, independent of the distribution grid. The system had to control the heating spirals in real time by the instantaneous irradiance and water temperature, protect the system with an emergency thermostat and allow operation and supervision from a distance.
VONSCH solution - turnkey
VONSCH products supplied
NEXICONTROL 
Scope of delivery (technical specification)
- PV inverter NEXICONTROL 400 050 PV (50 kVA)
- Switchboard R-FVZ with control system (Simatic PLC) and visualization, IP65/20
- Control of heating spirals EH1–EH4 and the WILO circulation pump
- Irradiance and temperature sensing
- Remote supervision eWON, RS485/Ethernet communication
- Design, switchboard manufacture, installation and commissioning
Project in numbers
50 kVA
PV source output
NEXICONTROL
400 050 PV inverter
EH1–EH4
heating + WILO pump
2026
Brezno · Slovakia
What the customer gained
- Water heated from own sunshine — lower electricity purchase.
- Energy used on site, in island (off-grid) mode independent of the grid.
- Control by irradiance and temperature — heat when the sun shines.
- Remote supervision (eWON) — operation under control from Brezno.
- Inverter and switchboard from the manufacturer — service from Slovakia.
Why VONSCH
We reduce the risk of a wrong decision - from design to service you deal with a single partner who stands behind the solution.
- A manufacturer, not a reseller - we develop and build power electronics in Brezno, Slovakia.
- A turnkey solution - one responsibility from design through installation to commissioning.
- Service and spare parts from Slovakia throughout the entire lifetime of the equipment.
