Servers are getting more powerful, many use multiple processors and hard drives. They’re are bigger and placed close to one another in racks. Data center is an environment where significant amount of heat is produced and traditional cooling solutions start to show their limitations. Liquid cooling solutions could be effective in reducing heat in server farms. However, the implementation of this solution hasn’t been popular or easy.
Liquid cooling has been used successfully in data centers to dissipate heat produced by servers. Air cooling is only useful if power consumption in each rack is below 5 kW. For smaller data centers, air cooling is the standard technology, but now because the heat density level rises significantly, liquid cooling starts to have more importance in the web hosting industry.
There are various types of liquid cooling technologies used by web hosting providers to remove excess heat generated by servers.
• Modular. It usually takes form as sealed cabinets that are placed at the base of server racks, with cooling capacity up to 30 kW
• Door. These full door units are fitted with large tubes that store chilled water.
• Rack. It is essentially racks with integrated cooling unit, power distribution and UPS. The cooling units pump cool water through tubing and coils to dissipate heat rapidly from the server interior.
• Liquid exchanger. This cooling solution involves heat exchanger filled with liquid refrigerant or chilled water and directly targeted to cool down hot spots.
• Mounted. Heat is dissipated by directing liquid coolant through sealed heat exchanger attached to the processors. The coolant has low boiling point and converted to gas quickly. Easily evaporated coolant can be more effective than chilled water as it can be replaced faster. Warm water has poor cooling ability and must be chilled again, which requires more energy.
Many web hosting providers have issues with heat and some of them need to expand the data center to manage the heat more easily. However, some are still against this solution and most data centers never use liquid cooling.
There are a number of scenarios in which data centers can benefit significantly from liquid cooling. A data center may need to be retrofitted quickly due to serious heat issues; however a transition to liquid cooling may raise some concerns including; is there any downtime while the liquid cooling is installed? Can liquid cooling improve uptime and reliability? What obstacles will need to be tackled when transitioning? Are the components durable enough to keep the coolant inside system and prevent leakage? Is the maintenance procedure simple enough? Can condensation be prevented inside the servers, in the racks and floors? These are a few concerns that should be addressed.
Another method is to install liquid cooling in new data centers. This is a much simpler process and can provide more benefits than retrofitting an existing cooling solution. Integration is simpler because the data center is designed with liquid cooling solution in minds.
Regardless of what type of liquid cooling solution used, there are a number advantages web hosts can get.
Liquid carries heat better than gas, for example water can dissipate heat 3500 times better than air, because water is a far better thermal conductor. Some special liquid coolant can perform even better than water. Due to its better cooling performance, web hosting providers can achieve higher server density. This will allow them to generate more profits per-square foot of data center space. As the result, web hosting providers can postpone the plan for the expansion of the data center.
Unfortunately, liquid cooling is more complex than fans and heat sinks. Consequently, this system requires more maintenance and can cause problems that must be anticipated.
These include, low coolant pressure, leaks, condensation inside the server and others. In addition, transition to liquid cooling can be time consuming and expensive, because the existing network and servers may not be designed to use liquid cooling.
Benefits of liquid cooling can outweigh the drawback, or vice versa, so web hosting providers need to evaluate their options carefully.