United Kingdom

CoolStream N natural evaporative cooler

CoolStream N provides low-cost adiabatic / evaporative cooling and ventilation principally for larger industrial premises with relatively high internal heat loads.

Product information

The CoolStream N adiabatic cooler helps keep larger internal spaces cool all year round. It doesn’t need to cost the earth: using the cooling power of water, it’s possible to achieve low energy cooling.

Fresh outside air is drawn in as the result of the natural thermal conditions within the building and passes through a wetted desorption medium and is cooled. The supply of cooled air at low level combined with removal of heat at high level via either natural or mechanical ventilators provide a pleasant temperature at the working area.

If the thermal movement is likely to be insufficient, the unit can also be equipped with continuously variable highly efficient EC fans.

Features and benefits

  • Evaporative cooling is up to 90% efficient.
  • A huge potential geometric face area (maximum of 20 m2 per unit) and high aerodynamic efficiency allow a large amount of air to pass through one unit to cool the low-level working areas.
  • Option of virtually silent EC fans to boost air flow and cooling capacity.
  • Modular design for easy installation and can fit into almost every type of wall.
  • High air quality: uses 100% outside air for cooling.
  • Low running and maintenance costs.
  • Simple and reliable technology.
  • Durable: with a corrosion-resistant aluminium casing. All components that come into contact with water are double coated.
  • Environmentally friendly and safe. No refrigerants (e.g. CFCs) used for cooling which would be harmful to the environment.
  • Highest degree of hygiene. Integrated water quality control system and tested to VDI 6022.
  • Digital control with master/slave operation, standalone operation and optional bus protocol (Modbus). Option for fully automatic control, comfortable control of room temperature and touch screen operation for up to 16 CoolStream N units in conjunction with exhaust ventilators or integration into a higher-level control system.

Applications for CoolStream N

CoolStream N is well suited to industries such as power generation, plastics, metal, or food, either as a new system or an add-on to existing natural ventilation systems.

CoolStream systems are popular with building operators and owners because of their low initial and running costs and low maintenance.

We offer you the CoolStream S for when only cooling combined with natural or mechanical ventilation is required. CoolStream S uses low-energy fans to move the air.

We offer you the CoolStream R as a second alternative for the complete air conditioning of industrial, semi-industrial and commercial spaces over the entire year. 

How adiabatic cooling works

Hot dry air is drawn across wetted media, resulting in an exchange of energy and a significant reduction in the temperature of the air. The warmer the outside temperature, the more efficiently evaporative cooling works.

Efficient and cost effective cooling - the hotter the better

If the ambient air is 30°C or above, the supply air can be cooled down adiabatically by at least 10°C. In general, the hotter the weather, the more efficient the cooling is. Evaporative cooling is up to 7 times more economical than conventional air conditioning systems, and has lower initial costs.

Cooling and ventilation in one system

Evaporative cooling involves supplying 100% fresh air and thereby maintains air quality. It is an enhanced input ventilation system, which means it can be used in spring and summer with the cooling function only being operated when conditions dictate. Excess heat is normally removed at high level via natural ventilators, providing a pleasant temperature in the internal space.

Boost your ventilation system with CoolStream N

CoolStream N is particularly effective in large spaces where a purely natural ventilation system cannot ensure a comfortable internal working climate. It is well suited for retrofit into existing natural ventilation systems to boost the cooling effect. The natural ventilation system is supported by the cooler inlet air, so that with the same free inlet area a lower room temperature can be achieved.


CoolStream N is mounted into the façade of a building. A conventional weather louvre system is fitted onto the outside of the unit. It is only 425mm in depth, allowing installation into most kinds of buildings.

Modular design – flexibility in design and installation

Its modular design and high degree of pre-assembly facilitate installation.

The modular system is available in 400 mm increments and up to 10 metres wide. It has four different heights between 666 mm and 2000 mm. Its largest standard geometric size is 20 m2. With only 425 mm overall depth and a wide variety of available paint finishes, the CoolStream N can be installed into most kinds of buildings.

Fan supported

If additional airflow is required, as an option CoolStream N units can be equipped with high-energy efficiency EC fans which provide the air flow the room needs. They operate independently from the conditions outside and operating at full variable speed, providing just the right amount of airflow.

Safe and environmentally friendly

The control system of CoolStream N is designed to ensure that water circulates safely, at the correct temperature. The process water is refreshed to avoid the growth of bacteria. The design prevents the incidence of sunlight and protects the desorption medium from the external environment. All this results in optimum water quality.

CoolStream N units have the highest degree of hygiene, with an integrated water quality control system, and they have been tested to and are in compliance with VDI 6022.

Energy and water efficient

CoolStream N units consume only around only around 50 litres of water per 10,000m³/h of supplied air, and use virtually no electric power.

Cooling tailored to the building

Colt can advise on all aspects of the ventilation design. With the help of the most advanced CFD calculations, Colt can provide support right at the start of the project and thereby provide definitive information as regards the expected performance and conditions within the conditioned space.

Limitations of application

CoolStream needs a suitable environment for it to be able to perform correctly.

It should not:

  • Be allowed to draw in air which is unusually humid or containing unusual amounts of particulates.
  • Operate with rain water, distilled and demineralised water or with contaminated drinking water.
  • Be used for the cooling of smaller spaces, spaces without the provision of exhaust air or spaces either with significant over- or under-pressure.
  • Be used in a space where a low humidity is needed or where there are corrosive gases.
  • Be used for the direct cooling of machines and processes which need an absolutely constant temperature and therefore constant cooling power independent of the ambient conditions, since the cooling power is higher in the summer than in the winter, and this depends on the weather.

Consult with Colt for further information.



Highly efficient evaporative cooling system for the façade. Provides cooled air as part of a balanced natural ventilation system, to keep the indoor climate cool. Uses only fresh outside air. Has an integrated water quality control system, and is fully hygienic. Can incorporate optional EC fans to boost air flow and cooling capacity if required. For combination with natural façade ventilators.

Size options


  • From 800 mm up to 9600 mm overall in 400 mm steps.


  • 666 mm
  • 1000 mm
  • 1333 mm
  • 2000 mm

Fan options

  • Natural cooling (no fans)
  • High-efficiency low noise variable 0-100% speed EC fans

Controls options

Touch screen controls, temperature and humidity options, BMS connections (ask Colt for further info)

Other options/ accessories

  • Two different pump sizes for different installation heights and free areas

Product video

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