• The energy self-sufficient Grabenmeier agricultural farm, Ahlen

  • Operated by Winkelmann Land & Forst GmbH & Co. KG

  • Date of commissioning: Disconnection from the grid: 11 February 2020

heating, solar thermal, potable and service water
separation, pressure maintenance, make-up, manifold technology, water storage technology

Performance parameter

  • 3 photovoltaic systems with 30, 30 and 25 kWp

  • CHP unit with 14 kW electrical and 19 kW thermal output

  • Battery storage with 135 kWh

  • 2 grid-forming inverters, each 42 kW


  • The entire farm is energy self-sufficient—no water or electricity from outside. The main energy source is three photovoltaic systems. Excess energy is either stored temporarily in two specially manufactured Reflex storage tanks and/or used for rapeseed oil production in a rapeseed mill. The electricity is also used by heating elements for hot water preparation and backup heating. In case of a shortage of solar energy (e.g. in winter), backup is provided by a CHP unit, which is operated with self-harvested and pressed rapeseed oil. Since the farm, and with it all its animals and inhabitants, is dependent on a reliable energy supply, the entire system must run faultlessly and redundantly

Product solution

  • Dynamic pressure maintenance

  • Ventilation: Reflexomat RS 90/1 with Reflexomat primary tank RG 800

  • Underfloor heating: Variomat

  • Servitec 35-T vacuum spray-tube
    degassing system

  • 2× Fillset Impuls make-up fittings

  • 2× Fillsoft softening systems

  • 2× Reflex Storatherm Heat Combi 20000-S

  • 4× EFHR 19KW electro flange heaters

Achieved goals

  • Everything from a single source – pressure maintenance, degassing, water make-up, water treatment, and distribution and storage technology, come as a complete system from Reflex and Sinus. This means the products are coordinated with each other, ensuring maximum operational safety and efficiency. State-of-the-art control technology also guarantees monitored and automated operation.