LowE technology for double membranes to increase the thermal efficiency of biogas plants

The question of energy efficiency and thermal efficiency is becoming more and more important, including in the biogas sector. To achieve significant reductions in the demand for heating and thus improve the energy efficiency of biogas plants, dbds – Deutsche Biogas Dach-Systeme GmbH uses patented Low Emissivity Technology (LowE). This involves a coating of aluminium particles applied to the PVC membranes in the factory on the outer face of the inner membrane or the inner face of the outer membrane. The principle of applying a coating with a low emmisivity is familiar from thermal insulation glazing, where it has become a tried and tested, state-of-the-art method.

An analysis of potential that was commissioned by dbds – Deutsche Biogas Dach-Systeme GmbH found that the LowE coating on the inner membrane of a sample fermenter with a diameter of 25.50 m, fitted with a double membrane shaped as a third of a sphere, resulted in a potential reduction in annual heating demand of between 12.6% and 19.1%. This analysis took into account the tank’s overall thermal losses, i.e. not just losses through the membrane roof but also losses through the tank floor and tank walls. The U-factor is around 2.21 W/(m²K) for double membranes with LowE coating compared to a U-factor of around 3.56 W/(m²K) for double membranes without LowE coating.

Low emissivity technology from dbds – Deutsche Biogas Dach-Systeme GmbH is thus an attractive solution for reducing thermal losses and improving energy efficiency. It does not require either additional insulation in the form of an extra layer inside the roof system or any additional work and expenditure during production or installation, since the membrane is already coated in the factory.