Intelligent heat pump system keeps the air clean and conserves resources

Albert Rechtenbacher GmbH and SIMAKA Energie- und Umwelttechnik GmbH

The SME winners of the Energy Efficiency Award 2021 for the ‘From clever to digital’ category carried out an energy-efficient upgrade of its automatic plastic painting line. In order to also reduce emissions during the post-treatment of exhaust air, an exhaust air purification system is now used instead of the afterburning method that is customary in the industry.

The Simaka site

Participating companies

Albert Rechtenbacher GmbH and SIMAKA Energie- und Umwelttechnik GmbH

Project location

Bopfingen, Baden-Württemberg


Energy and environmental technology

Technologies used

Exhaust air purification system based on heat pump technology instead of a thermal afterburning system

Energy efficiency

Reduction of energy consumption: 1,243,000 kWh/yr   Thermal energy savings: 95% exhaust air purification process; 80% all other processes

CO2 savings

309 t CO2e/yr



Payback period

0–3 years

Funding programmes



Albert Rechtenbacher GmbH (Rechtenbacher) is based in Bopfingen auf der Ostalb, Germany, and is an expert in surface finishing and surface treatment. In 2017, it carried out an energy-efficient upgrade of its automatic plastic painting line. Various options for the post-treatment of exhaust air containing solvents were investigated in order to find one that complies with legal regulations and guarantees clean, environmentally friendly operation. The industry standard for purifying exhaust air is thermal afterburning. However, this method carries the disadvantage of consuming a large amount of fossil fuels.

This is why SIMAKA Energie- und Umwelttechnik GmbH developed and installed a highly efficient exhaust air purification system for Rechtenbacher based on its own heat pump technology. Rechtenbacher can now separate the solvents from the exhaust air using the condensation principle instead of a thermal afterburning system. The exhaust air is cleaned using an activated carbon filter. Doing so reduces gas consumption by 95 per cent and significantly reduces CO2emissions. The activated carbon is regenerated over the weekend using a heat pump, and the solvents are recovered. Using the heat pump technology is particularly efficient at Rechtenbacher because heating and cooling are needed at the same time. For heat utilisation, a COP of four is considered technically achievable. By simultaneously utilising the cooling process, the efficiency increases from a COP of seven to a COP of ten. The waste heat from the heat pump is used to do things such as heat the cleaning water for the system that washes the parts that are to be painted, for the conditioning of process air and for heating the building. What’s more, additional energy savings were achieved by installing energy-efficient heat pumps for recirculation or supply air operation in spray booths and various dryers.

Another view of Simaka


The heat pump-assisted exhaust air purification process is transferable to all businesses that emit volatile organic compounds (VOCs) and need to purify their exhaust air. Using heat pumps for simultaneous heating and cooling is recommended for all industries where thermal processes take place on a large scale.

Energy Efficiency Award 2021

Award winners 2021

Around 130 applications from Germany and around the world: the Energy Efficiency Award is once again a coveted award in the context of energy… Read more

Pictures: SIMAKA Energie- und Umwelttechnik GmbH