In this article, in a very simplified way, we see what is meant by free cooling, and how it can be a valid alternative, convenient under the right conditions.
Free cooling is a special cooling method which uses external temperatures to dissipate the heat inside a closed system. It is a very efficient solution which, if used in the right environments, can result in considerable savings.
There are many possible applications for this cooling system, ranging from manufacturing industries to support systems for server farms. It is extremely cost-effective, especially because with 100% free cooling access, the compressors are switched off, with considerable extra energy savings.
How free cooling works
The most common cooling systems are based on a closed circuit, containing water maintained at a constant pressure. It is a bit like the liquid cooling system found in the latest computers. This system does not require any external water, or for any water to be poured, as it always uses the same liquid, contained within the system itself.
Its operation is relatively simple: the water follows a precise route, absorbing heat from the machines or from the rooms, then carrying it to be cooled via free cooling. The device is usually placed on the outside and is designed to release the heat accumulated by the water in that environment, but without using any extra energy.
This phenomenon is possible thanks to a particular design feature. Free cooling systems operate, in fact, only if the external temperature is lower than the temperature of the hot water flowing out of the system. This allows for natural heat exchange which absorbs the heat from the ‘loaded’ water and makes it cool again, ready to repeat the cycle from the beginning.
In the right environmental conditions, it is easy to see why this system is so economical. From a cost point of view, the almost negligible energy consumption means considerable financial savings (for example, the cooling of a server room using free cooling costs around 34,000 Euros a year, while the cost using other systems can be over 296,000 Euros).
As far as environmental pollution is concerned, free cooling statistics are extremely positive, as it produces almost no emissions and energy consumption is close to zero. It is therefore a sustainable solution which factories are free to use according to their requirements.
Alternative solutions to free cooling and hybrids
The greatest limit of free cooling is the external temperature. In order to find out if this type of solution could be suitable for your business, the following guidelines can be used:
- If the external temperature is lower than that of the outflowing water, then free cooling will work;
- If this prerequisite is not present and the temperature varies according to the month and season, it is best to choose other options.
Operating without free cooling can turn out to be very costly compared to free cooling, although it guarantees complete independence from external variables. There is also an option which offers the benefits of free cooling combined with the versatility of traditional systems: the hybrid solution.
In this case, the cooling system allows for a device for free cooling to be positioned in series with another one using a refrigerant or compressor. In this way, the external temperature can be used when suitable and the chiller can be used during the colder winter months. This is a good way to save money, without too many restrictions.
Translated by Joanne Beckwith