A new video by the VDI ZRE shows resource efficiency with a practical example
In 2019, the Alois Müller company from the Allgäu region opened its Green Factory at its Ungerhausen location. The Green Factory is a virtually energy-self-sufficient production and office building. HVAC systems and components for metal construction are produced here.
A photovoltaic system on the roof of the production hall has a maximum power output of 1.1 MW and supplies two-thirds of the required electric energy. It also feeds power into the public electricity grid. Excess waste heat from the biogas-fired combined heat and power plant and from a pellet boiler is caught in a buffer tank with a capacity of 100,000 litres. This waste heat is later used within the company and also fed to a local heating network that supplies the neighbouring company.
The entire product planning is designed to optimise solar power usage. This works only if the procedures are digitalised. An intelligent ERP system provides the head of production with an overview of how power is going to be consumed over the next few hours and the electricity supply from the roof. Therefore, the production steps consuming the most energy are temporarily adjusted to the available electricity supply. This includes the production of the auxiliary and operating materials used as energy accumulators.
The energy accumulators used for the optimum exploitation of solar-electric energy include nitrogen produced in-house, fully desalinated water and compressed air. These media are usually produced while the sun is shining. Preferably on weekends, when production does not need energy. Furthermore, a 230 kWh lithium battery stores the solar power. When sunshine is lacking, a combined heat and power plant fired by biogas covers the demand of energy. A pellet boiler provides additional heat during extended cold periods. The company operates its own electric charging station with the self-generated power. Vehicles not affiliated with the company may also use it.