Battery dry rooms represent over 43% of battery production energy usage, which is why Weiss Klimatechnik chose Cotes Ultradry dehumidifiers to meet the extremely dry air requirements of dewpoints below -78°C whilst reducing net energy usage of the battery dry rooms dramatically. 

"With the expertise of Weiss and the energy-efficient dehumidifiers from Cotes, this research facility in Münster will have one of the world's most energy-efficient battery dry rooms," -Dirk van Manen, Managing Director, Weiss Klimatechnik GmbH.

Cotes Ultradry dehumidifiers enable the drying room to operate at an energy consumption rate of just 16%. In contrast, competitors' solutions utilizing only one rotor consume energy at a much higher rate of 57%. This stark difference results in an impressive net energy savings of 85% when employing Cotes Ultradry Adsorption Dehumidifiers, highlighting their high energy efficiency.

The overall reason for the significant reduction in energy consumption of the dehumidifiers lies in the low nominal temperatures and efficient use of sustainable energy sources. Here, Cotes developed a patented technology called Exergic that does not need to burn gas and can source its energy from a range of sustainable sources.

"Our machines prefer temperature margins of 80-90°C, significantly lower than the closest competitors' solutions that run optimal conditions at 140-180°C and burn gas to reach those temperatures. Using lower temperatures means energy consumption is reduced and safety margins are better," -Thomas Rønnow, Business Development Manager and Owner of Cotes.

Cotes Ultradry Adsorption Dehumidifier environment



Lithium-ion batteries and other sustainable energy storage systems require extremely dry and extremely clean conditions during research and production. To ensure these conditions, Weiss Klimatechnik chose the most energy-efficient dehumidification system for drying air. The solution, developed by Cotes, not only fulfils every climatic requirement but also scores highly for energy efficiency. Saving energy is essential because drying air by adsorption can be highly energy-intensive. However, Cotes' dehumidifiers enable various energy-efficient fresh air treatment, regeneration air treatment and heat recovery processes.


The 3,000 m2 research facility includes around 1,500 m2 of cleanroom and dry room space and airlocks and equipment areas. In the dry rooms, the residual water content of less than 0.001g/kgTrl (grams of water per kg of air) is required. Cotes Ultradry adsorption dehumidifiers deliver dewpoints of below -78°C. Ultradry air is of paramount importance because lithium reacts powerfully with water, releasing explosive hydrogen, and even average humidity can cause exothermic reactions. As a result, certain areas of the facility must be run with extremely dry air.


  • Ultradry Adsorption Dehumidifiers with 3 rotors
  • 8 intake + 8 main units 
  • Supply dew point at -78,5°C
  • 2 persons in the dry room
  • Return air at 22°C
  • Energy source: Ammonia heat pump to heat hot water

Watch the video showcasing the project's progress. Pay close attention to the last 30 seconds, where you can see the Cotes UltraDry Adsorption Dehumidifiers neatly placed on the steel framework, ready to be installed in the clean and drying rooms.



Weiss Technik Logo

The Weiss Technik companies, part of the Schunk Group, include the product areas of environmental simulation, heating technology, air conditioning technology and pharmaceutical technology, Customers receive solutions and products that are used in research and development as well as in production and quality assurance. A strong sales and service organisation with 22 companies in 15 countries at 40 locations support the customers and ensures the operation of the systems - around the globe. The Weiss Technik companies are part of the Schunk Group based in Heuchelheim near Gießen.


Fraunhofer FFB Lithium-ion battery dry room dehumidification

The Fraunhofer Research Institution for Battery Cell Production FFB is a facility under the umbrella of the Fraunhofer-Gesellschaft. Its concept involves a combination of laboratory and production research for different battery cell formats – round cell, prismatic cell and pouch cell. Fraunhofer FFB employees research individual process steps or the entire production chain as required. Together with the project partners of the MEET Battery Research Center of the WWU Münster, the Chair PEM of the RWTH Aachen University and the Research Center Jülich, Fraunhofer FFB is creating an infrastructure with which small, medium-sized and large companies, as well as research institutions, can test, implement and optimize the near-series production of new batteries. The German Federal Ministry of Education and Research (BMBF) and the state of North Rhine-Westphalia are funding the establishment of the Fraunhofer FFB with up to a total of 680 million euros as part of the "Research Fab Battery Cells (FoFeBat)" project.



Cotes offers an Ultradry dehumidifier for battery dry rooms that uses our Cotes Patented Exergic Technology, enabling massive energy reductions, cost savings, and huge CO₂ emissions reductions of up to 95%.

Did you know that:

  • Dehumidification for battery dry rooms counts for 43% of energy consumption in battery cell production
  • Cotes Exergic Technology can cut battery dry room dehumidification energy consumption by 30-50%. The remaining energy required for drying the battery dry room can be sourced from waste heat or heat pumps, enabling a total reduction in a range of 80-90%.
  • It is possible to reduce the cost of the energy bill for dry room dehumidification by up to 66%
  • With the right dry-air solution for your battery dry room, it is possible to cut the total CO2 footprint of battery packs by 7-9%

If you are a car or battery manufacturer that wants to go green(er) and save costs, then reach out to us.

Cotes can help you find the right dry-air solution for your facilities and give you the competitive advantage of a more sustainable Li-ion battery.

Contact Vincent von Wieding, Head of Battery Manufacturing Unit for more information at






Are you curious about the potential energy savings for your battery dry rooms? Take a look at our free online calculator below.

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