Alternative text

Maximum efficiency and savings: free cooling

Many applications, for example in process cooling, call for efficient refrigeration capacity even in winter and transitional periods. If ambient temperatures drop below the refrigeration supply temperature, it is possible to utilise a process of heat transfer between the ambient air and chilled water. This process, referred to as free cooling, lowers the demand for power – and increases your energy efficiency.

The advantages of the free cooling systems at a glance

Higher energy efficiency
due to lower demand for power
Lower operating costs
if a suitable free cooling system is chosen
Reduced power consumption
by up to 40 per cent
Up to 70 per cent of refrigeration requirements
are covered by the free cooling system – even in winter
Various versions available
depending on your needs: external, integrated, or thermosiphon function
Three operating modes
depending on the ambient temperature: free cooling mode, combined operation and compression mode
Also all the advantages
of our powerful air-cooled QUANTUM Air series
QUANTUM Air with free cooling systems

Three versions of free cooling

We at ENGIE Refrigeration are one of the few manufacturers to cover all versions of free cooling. Whether external, integrated, or with a thermosiphon function.

Free cooling can only work if the ambient temperature lies below the cold water temperature. The advantage of this process is that you do not need to run the refrigeration system’s compressors. This increases your energy efficiency as an operating company and also saves you money. Accordingly, it is especially suitable for applications with a chilled water intake temperature of around 13°C.

To make sure that the chosen solution always provides the ideal balance between free cooling capacity, investment costs and system dimensions, our portfolio includes various system solutions for free cooling. They all have one thing in common: they come from the range of air-cooled QUANTUM chillers, and are integrated mechanically, hydraulically and in terms of control systems.

The QUANTUM chiller’s PLC automatically switches from compressor mode to free cooling mode and back according to the operating conditions. Combined operation is also possible. With this intelligent regulation, you are always on the safe side when it comes to maximum energy efficiency and reducing operating costs

If an integrated free cooling module is suitable for you, you will benefit from the following advantages:

  • The space-saving solution is extremely compact and therefore requires very little space.
  • At the same time, it achieves a high free-cooling performance.
  • The integrated solution is especially suitable if your performance demand is high even in winter and transitional periods.
  • In process cooling in particular, for example in data centres, integrated cooling shows its full potential.
  • Low electricity costs in free cooling and combined operation save money.

In case of the integrated free cooling module, additional water-air heat exchangers are installed in the condenser modules. Flow through the sandwich structure with free cooling module and the condenser is produced by the same fan.


External free cooling modules offer operating companies the following advantages:

  • A high EER is achieved in free cooling mode.
  • You benefit from a significant reduction in power consumption.
  • Where climate control and process cooling are combined, an external free cooling module is unbeatable.
  • Thanks to the energy savings, the procurement costs will amortise quickly.
  • Electricity costs are considerably lower in free cooling and combined operation than in compression mode.

The external free cooling module is placed onto the chiller’s base frame and integrated hydraulically.

The thermosiphon function differs from the integrated and external versions. It offers operating companies the following advantages:

  • The cost of the thermosiphon function is relatively low.
  • You do not require additional heat exchangers.
  • A thermosiphon function is the right choice wherever there is a low performance demand for free cooling.
  • As with external cooling, the combined application of refrigeration supply and process cooling is possible.


Two motor-driven ball cocks bridge the compressor and the expansion valve in the refrigerant circuit to allow the refrigerant to circulate freely. The low ambient temperature causes the refrigerant to condense in the condenser. From there it flows into the evaporator, where it absorbs heat and evaporates.

QUANTUM Air with free cooling


free cooling modules are deployed with our ultra- efficient QUANTUM Air. In addition to the many advantages of a free cooling system, you will of course also benefit from our powerful air-cooled series. See for yourself:

  • Efficient re-coolers
  • Low-noise chiller operation
  • Silent compressor technology
  • Open-flash economizer
  • Two-stage oil-free turbo compressor
  • Generously dimensioned evaporator
  • Electronic expansion valve


Learn more about our QUANTUM Air

Would you like to talk to us and find out what version of free cooling is right for you?