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Free cooling: Is it a viable option for Indian enterprises?

Jasmine Desai, Principal Correspondent

Reduction of data center power consumption is now a top IT priority in Indian organizations, especially in today's challenging economic climate. This need is substantiated by the Data Center Purchasing 2009 Survey conducted by SearchDataCenter.in, which clearly indicates that reduction of power consumption is a major priority for Indian enterprises. More than 77% of the surveyed Indian organizations consider reduction of power consumption as a prominent data center agenda item for 2010. While free cooling can definitely be an option on this front, the practicality of this cooling method in India is still under explored.

"Free cooling" is a trend that can translate to several cost benefits from a data center front — if implemented right! Now that we have this part out of the way, it's essential to clarify that the "free" word in free cooling does not translate to zero implementation or usage costs. Free cooling just means that artificial cooling methods can be complemented by the use of natural air and water as cooling mechanisms. While this does come at a cost, it has its attendant benefits in the long run.

As a concept, free cooling means the use of outside air or water at a certain ambient temperature (preferably 21-25 degree Celsius) to cool data center equipment, instead of artificial air-conditioning or precision cooling. Free cooling can be achieved by two methods — air-side and water-side economizer based cooling.

Air-side economizers

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depend on air handling units which use cold outside air as the input. This cold air is filtered and then circulated within the data center. On the other hand, water-side economizer based free cooling methods rely on water towers (that use chillers). This chilled water is used for data center through high-end ducts connected to the racks. Selection of a free cooling method depends on your data center's location, climate, availability of equipment, and the resultant feasibility.

A data center which already uses precision cooling will have to install more equipment to use free cooling. On top of that, free cooling can be used only during certain months of the year.
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The Indian scenario

The majority of Indian organizations still remain skeptical about usage of free cooling. "Although Indian CIOs are very skeptical about free cooling, it's not possible to ignore its benefits, as compared to precision cooling. Free cooling offers substantial operational expenditure benefits and improvements in the data center's power usage effectiveness (PUE)," says Manish Bhatnagar, the vice president of APW President Systems Ltd's cooling solutions division.

Notwithstanding this, free cooling is considered as a business risk by many Indian CIOs, since data centers are critical resources. "India has a lesser number of free cooling implementations when it comes to core production environments. I have come across organizations which very seriously evaluated free-cooling, but could not take it beyond because of the risk factor. Also, there can be issues with free cooling if an organization uses high density servers," says Saji Thoppil, the general manager of Wipro Infotech's platform practice.

A successful free cooling implementation depends mostly on the data center's location. Most Indian organizations with captive data centers look for nearby sites, which may not be feasible from a free cooling standpoint. This issue is compounded by the lack of relevant climatic information. "There is dearth of sufficient data when it comes to the number of cooling hours available in a specific Indian city. The available calculators are meant only for the cities in Europe or U.S. Hence organizations will have to conduct independent studies to counter such problems." says Bhatnagar.

Locations which offer the ideal climate for free cooling (like those in remote North India) face infrastructural issues. Bad connectivity and poor power availability are the norm in these places. Another challenge is availability of skilled technical (IT support staff) in such areas.

Implementation challenges

Air-side economizer based free cooling methods can be quite challenging to implement in locations where unreliable climatic conditions can result in varying temperatures. Apart from this, air quality (the level of dusty and outside impurities) is poor in India. This can directly lead to failure of servers and other data center equipment. While it's possible to deploy air filters to save data centers from dust, this is not a completely safe arrangement.

Humidity is another glitch associated with air-side economizer based free cooling methods. "Humidity control is difficult, so levels can vary between 2% to 90% RH (Relative Humidity). This may be well beyond the ASHRAE (American Society of Heating, Refrigeration, and Air-conditioning Engineers) 9.9 standards. Hence you may require additional air-conditioning equipment," says Bhatnagar. When it comes to water-side economizers, corrosion of data center equipment (due to the usage of water) can be an issue.

On the cost front, free cooling can be substantially expensive to implement, compared to normal data center cooling methods. For example, today you can procure a precision cooling unit of 1 Ton capacity in the price range of Rs 11 Lakh. On the other hand, water-side economizer based free cooling equipment (which uses ducts attached to the server rack for water flow) can cost almost double this amount. These figures can add up on your capital expenditure front, since traditional cooling approaches are required to supplement free cooling methods.

A data center which already uses precision cooling will have to install more equipment to use free cooling. On top of that, free cooling can be used only during certain months of the year — not a very cost-effective solution. Such conditional feasibility for free cooling in India makes it suitable only for large data centers. Hence we are of the opinion that it will be quite a while before free cooling methods become common among Indian organizations.