Free cooling is a technology for generation and delivery of useful cooling energy with minimal consumption of electricity. The word “free” in its name illustrates the fact that its source – low-temperature ambient air - is readily available and free of cost.
How low is low enough?
Low-temperature ambient air means different degrees Celsius for different consumers. A key term here is the set-point temperature, in other words, the temperature which needs to be maintained in the manufacturing process or in the space that has to be cooled. The free-cooling mode becomes available when ambient air temperature drops by at least 2 degrees Celsius below the set-point temperature.
Who can use free cooling?
The most suitable environment for free-cooling technologies is a combination of a cold or mild climate zone and consumption of cooling energy all over the year, round-the-clock. This encompasses many manufacturing industries, data centers, and spaces where constant temperature and humidity levels must be maintained (clean rooms, cold rooms, certain areas of hospitals, etc.). Some examples of suitable manufacturing industries are the energy-intensive sectors of plastic, food, metal, and pharmaceuticals.
To understand whether you can benefit from free cooling, start considering the following questions:
- Are you in a cold or mild climate zone?
- Do you need cooling energy all over the year or only for a few months?
- How many kilowatts of cooling energy do you consume per month?
- If you have chillers, how efficient are they? How much do you (or would you) pay for electricity for cooling?
- Does your country provide subsidies for energy efficiency and reduced carbon emissions?
As this is just a starting point in the evaluation, do not hesitate to contact us for a detailed analysis and consultancy on free cooling feasibility for your environment.
Free cooling technologies
Free cooling systems, also called free cooling chiller plants, can be based on air-cooled or water-cooled electric chillers. Both integrate a “traditional” cooling mode with a free cooling mode when the ambient temperature values are appropriate. In the free cooling mode, the chiller compressors are automatically switched off and the only consumption of electricity is dedicated to the circulation pumps and fans, which ensure the distribution of the generated useful cooling energy.
The choice between the two technologies is determined by a number of factors, such as the availability of water and its cost, the available space for a chiller, the cost of electricity in the particular country and the period of time during the year in which free cooling can be used. Water-cooled chiller plants reach higher energy efficiency rate compared to air-cooled such, and occupy significantly less space.
Free cooling versus traditional chillers
The energy efficiency rate differs significantly between traditional electric chillers and such with free cooling functionality, not only in the winter but also in the summer. Here is a comparison of the average seasonal energy efficiency rates for the generation of 1200 kW of cooling energy:
|Air-cooled electric chiller||EER 2,5||EER 3,5|
|Free-cooling water-cooled chiller plant||EER 4,5||EER 24|
|Air-cooled electric chiller consumption||480 kW electricity||343 kW electricity|
|Free-cooling water-cooled chiller plant consumption||267 kW electricity||50 kW electricity|
Range of cooling capacity
From 400 kW to 1200 kW of cooling energy can be delivered by a single-module free cooling chiller plant. As the modules are scalable, practically any needed cooling capacity can be achieved.
Modern free cooling chiller plants have a dedicated software which not only decides when to turn on the free cooling mode but also how much cooling energy to produce based on the cooling energy need at any particular moment.
Free cooling chiller plants have a longer life-cycle compared to traditional chillers because of the reduced number of operation hours of the compressor during the year. All the maintenance and service activities are planned and monitored via a dedicated software, which also manages the switching between the ordinary and the free cooling modes.
Check our client testimonials and case studies to see the results achieved in different sectors.