K, L, M, N, O, P

The heat transfer coefficient, also known as the k-value, is a measure of the quality of thermal insulation. It indicates the heat flow that passes through a square metre of a building component at a temperature difference of one degree Celsius. The smaller the k-value, the lower the heat loss.

Attachment on the fermentation tank in which biogas is collected and extracted

Colourless, odourless and flammable gas. Burns to form carbon dioxide and water. Methane is one of the most important greenhouse gases and is the main component of biogas, sewage gas, landfill gas and natural gas. Methane forms explosive mixtures with air.

The gases nitrogen monoxide (NO) and nitrogen dioxide (NO₂) are summarised under the term NOx (nitrogen oxides). They are produced in all combustion processes (especially at high temperatures) as a compound between the nitrogen in the air and the oxygen, but also by oxidation of nitrogenous compounds contained in fuel.

Portion of a mixture of substances reduced by the water content and the inorganic substance, usually determined by drying at 105 °C and subsequent incineration at 550 °C.

Organic fraction of the material introduced into the digester, related to the usable digester space volume per time unit; unit: kg oDM/m³*d.

Pre-treatment process step (e.g. crushing, separation of impurities, homogenization, chopping...)

Spatial areas in which a hazardous explosive atmosphere may occur due to local and operational conditions.