Smart Building

Thermochromic coatings change their colour and transparency depending on the temperature. These coatings contribute to the energy efficiency of buildings by automatically regulating the heat flow and thus reducing the need for cooling and heating.

•  Reduction of heat radiation through window glass into the building
• Utilizing the effects of thermochromism, i.e. switching the energy flow by exceeding/falling below a certain temperature

Research focus

• Coating technologies for thermochromic elements on ultra-thin glass (approx. 100 µm) and other substrates
• Adaptation of the composition, process control and structure of the coating system for adapted switching temperatures
• Optimization of manufacturing costs through process developments in roll-to-roll processes
• Scaling up the process technology from laboratory to pilot scale

Minimization of heat losses through low-E coatings

Special low-emissivity coatings on glass reduce the emission of infrared radiation, e.g. in windows and glass façades, and thus improve their energy efficiency by minimizing heat loss. In doing so, low-e coatings allow visible light to pass through to a large extent, but reflect heat radiation (infrared radiation) back into the room. This keeps the interior warmer in winter and cooler in summer, which helps to reduce the heating and cooling energy requirements of buildings.

Research focus

• Optimization of the properties of low-E coatings
• Replacing scarce materials in the manufacturing process

Solar control coatings by Solar-Control

Solar Control coatings (solar control coatings) consist of ultra-thin layer systems that are applied to glass to reduce the amount of solar energy that penetrates the glass. These coatings allow most of the visible light inside the building, but block a significant amount of infrared radiation (heat radiation) and UV radiation on glass facades and windows. The main advantage of solar control coatings is that they reduce the heating of interior spaces by solar radiation without darkening the room significantly. This makes a significant contribution to increasing building comfort and offers potential energy savings in building air conditioning.

Research focus

• Optimizing the properties of SolarControl coatings
• Replacing scarce materials in the manufacturing process

A wide variety of surface functionalities and finishes are relevant for building interiors. Processes such as paint curing and surface modification of various substrates using electron beam technology are used here.

Research focus

• Coatings for decorative surfaces
• Easy-to-clean surfaces
• Antibacterial surfaces

In the construction and building sector, sustainable solutions for reducing energy requirements and improving the carbon footprint are more in demand than ever. In view of rising energy prices and strict regulations for lower energy consumption in buildings, innovative technologies such as perovskite and organic solar cells offer great potential.

The Fraunhofer FEP is developing new coating and process technologies that will significantly increase the durability and efficiency of solar cells and sustainably reduce costs and material requirements.

The institute is also working on new, optically effective surface structures for perovskite solar cells. The use of roll-to-roll nano-imprint lithography should minimize reflection losses and increase the efficiency of solar cells. This also opens up new applications in the field of design PV. 

Research focus

• Barrier layers for organic solar cells
• Development of flexible perowskit solar cells
• Research into new materials and coating technologies for sustainable, long-lasting solar solutions
• Innovative processes for structuring surfaces for design PV applications
• Development of novel combinations of permeation barrier and transparent electrode layers
• Development of new, optically effective surface structures for perovskite solar cells

Innovative coating technologies that maximize the efficiency of solar absorbers, thermochemical heat storage systems and adsorption chillers are crucial to advancing the heat transition. The Fraunhofer FEP develops customized coating systems that meet specific requirements for absorption, emission and heat conduction and thus sustainably support the use of renewable energies.

Efficient solar absorbers with optimized layer systems

High-performance solar collectors require absorber layers that effectively absorb solar energy and minimize heat loss. These layer systems absorb light in the visible and UV range and emit little infrared radiation, thereby increasing the efficiency of heat utilization.

Research focus:

• Optimization of absorption and emission characteristics through precisely coordinated layer thicknesses
• Long-term stability and temperature resistance of the coatings under cyclic loads
• Development of high-precision coating technologies for absorber tubes in solar collectors

Improved heat conduction in thermochemical storage systems

Zeolite-based thermochemical storage systems enable the seasonal storage of heat through adsorption and desorption. Special coatings increase the thermal conductivity and support the efficiency of heat storage and retrieval, which simplifies the use of the stored energy.

Research focus:

• Metallization of zeolite granules to increase thermal conductivity
• Porous layers for unhindered diffusion and rapid adsorption processes
• Efficient heat transfer solutions for storage and retrieval via heat exchanger surfaces

Compact and efficient high-temperature heat accumulators 

New hybrid materials are being developed to enable higher storage densities and smaller storage systems. The metallization of such materials improves heat conduction, which further increases the efficiency and compactness of the storage units.

Research focus:

• Development of hybrid materials for maximum storage capacities
• Increasing thermal conductivity through targeted metallization
• Integration of new storage materials in sustainable and scalable storage solutions

Increasing efficiency in adsorption refrigeration technology

The coating of adsorption chillers enables sustainable cooling using solar energy or waste heat. This helps to reduce the need for electrical energy for conventional compression refrigeration systems.

Research focus:

• Optimization of coatings to improve heat transfer in adsorption chillers
• Development of coated refrigeration systems for stationary and mobile applications
• Integration of adsorption refrigeration in industrial and mobile heat utilization systems