Energetic and economic optimisation of drying processes by integrating heat pumps

Drying processes require at least 15% of the total industrial energy demand. In some sectors, e.g. the wood industry, this proportion can reach 70%. Numerous studies have shown that up to 50% of primary energy can be saved by drying with heat pumps. However, this potential has so far only been realised industrially in exceptional cases, as the operation of heat pump dryers is much more complex than the operation of the individual system components.

The aim of the project is to develop various heat pump-assisted drying processes on a pre-competitive basis and to demonstrate their energy and economic efficiency for several industrial sectors. The focus is on convective drying processes, which are the most widespread and can be advantageously supplemented with heat pumps. The cross-industry interest of the 37 German and 15 Belgian companies involved from the fields of drying, heat pumps, the wood industry, bricks and ceramics, medicinal and aromatic plants, textile production, laundry drying, sewage sludge and fermentation residues is correspondingly high.

Based on the current state of science and technology, established and innovative technical solutions are analysed. The project focuses on the effective integration of heat pumps into the respective drying systems and their quality- and energy-optimised operation with largely automated process control under varying conditions. Scientific challenges result from thermodynamic and process engineering interactions between heat pumps and dryers. The project results will be demonstrated on a laboratory and pilot scale and on a production plant. Industry-specific possibilities and limits for economic realisation are shown. Industrial case studies and scientific publications serve to accelerate technology transfer.