Cooling water data-center
The number of datacenters continues to grow in response to the enormous amount of digital information stored and streamed. Even though technology continues to advance, the consumed power is rising as more cores and CPUs are packed into smaller spaces and server densities steadily increase.
The great amounts of energy used create massive heat which makes servers slow down or malfunction. In this context, efficient cooling has become a key building requirement and traditional cooling systems are not fulfilling the demands. Also, increases in energy prices have forced many IT technicians to confront the inefficiency of current practices.
Water vs air cooling
There are multiple ways to cool data centers, depending on their, computer capacity, energy costs, water availability, data load and server density. Popular options in the market include water-cooled plants and air-cooled plants. When comparing water cooling vs. air cooling techniques in data centres, you will find that air cooling is more popular but that water cooling may be more cost-effective.
Being a gas, air has poor heat conductivity, meaning that the amount of energy required to chill down air to required temperatures and to move it is becoming somewhat expensive. Water has much more capacity to remove heat than air and can therefore be far more effective to cool hotspots if it’s engineered and implemented in the correct manner. Using water-cooled systems versus air-cooled systems can significantly reduce your cooling energy costs. Surprisingly it can also reduce your water footprint. Because the water used in a power plant to make the additional power the air system needs is actually greater than the amount of water that would be used locally by a water cooled system.
The benefits of water cooling systems include:
- Tenfold increase in server density,
- Much less energy required for cooling,
- Less time for production and return on capital,
- No need for custom building architecture,
- Increased infrastructure reliability,
- No need for re-characterizing air flows prior to moves, adds or changes,
- Much improved work environment (noise reduction).
Water cooling has been a concern for many data center operators due to possible leakage, however this technology has matured to a point where that should not be a problem. The use of water to more effectively cool hotspots allows to optimize energy usage and provides the capability to operate high-availability and high-density datacentres for the future. In most scenarios water cooling is indeed considered a best practices method. Water-cooled technologies are even more efficient when “free cooling” is employed during periods of cooler weather.
In reality, cooling towers do not keep things cool as much as they reject heat, which they do by transferring heat from the water source to the atmosphere through the process of evaporation (latent) and sensible heat transfer, thereby reducing the water temperature. The industries use cooling water for various jobs and, as a result, there are also various types of cooling towers.
A properly chosen and maintained cooling tower can help organizations avoid problems in its operation. Choices must be made on the basis of size, efficiency, dynamics, and other factors.
Cooling make-up water treatment
Water sources that are applied in cooling towers often contains salts (such as chlorine, sulphates and carbonates), dissolved gases (such as oxygen and carbon dioxide) and metal ions (such as iron and manganese). The presence of these pollutants can cause a series of problems, including fouling, scale formation, corrosion and biological growth. Pathogen microorganisms, such as Legionella bacteria, must be deactivated. As such, cooling tower water treatment and disinfection systems are of primary importance to meet demands that differ from the standard ones for drinking water and swimming pool water.
Figure 1. Diagram of data center water cooling technology with make-up water pre-treatment by reverse osmosis membranes
Lenntech has engineered, manufactured and assembled several turn-key water treatment plant for cooling water supply for datacenters. Lenntech solutions allow a reduction of water consumption by 20-30% in the cooling units, and consequently waste water (blow-down) minimization. In addition, the purified water and the high recovery rate allow a reduction in the amount of chemicals used to maintain the cooling water quality.
This system can be containerized or skid mounted, compact, plug-and-play solution, minimizing site works and footprint.
