Green strategies for cool data centres

01 May 11

An IT reseller’s role as a strategic consultant to customers should never be underestimated. Your advice is often pivotal in your customers’ decision-making process, and in a highly competitive market your ability to offer advice that goes beyond the spec sheets of the products you sell sets you apart from the crowd.

One area often overlooked by strategic consultants is the green data centre. Don’t get me wrong – the data centre is one of the most active trading floors when it comes to reselling IT and communications equipment, but beyond the sale, what value can you add to the process as a trusted advisor?

Simply put, green equates to energy efficiency, which – if managed correctly – equates to CAPEX and OPEX savings for your customers. More importantly, these savings can be realised by following a number of basic strategies, some of which don’t require any additional spend and can be had using existing equipment or infrastructure.

Until recently, little attention has been given to the cost of energy used by IT systems. But as power consumption and electricity prices rise, energy costs are receiving more scrutiny from senior-level executives seeking to manage dollars. In fact, energy costs have now become one of the driving factors in decisions regarding data centre location and design.

There are a number of strategies that can be evaluated for reducing IT system energy consumption, most notably server consolidation and virtualisation. However, I’d like to focus instead on the heart of the data centre – the infrastructure, and more specifically, cooling.

Up to 50% of a typical data centre’s power is consumed by essential support systems, such as power, cooling and lighting. Next to technology systems themselves, the cooling system consumes the most energy in the data centre, accounting for 37% of data centre electricity use.

Demands on cooling systems have increased substantially in recent years as server densities have risen to unprecedented levels. This change has not only created the need for increased cooling system capacity, but has also exposed inefficiencies in existing approaches to data centre cooling.

As a result, cooling now represents the second highest opportunity for IT energy cost savings. And for a reseller it represents one of the biggest latent opportunities for adding real value to your customers’ investments.

The five strategies

Picture this scenario: you’re in a competitive tender for a large data centre project in Auckland, facing some of the biggest names in the business. The tender is fairly typical – a mid-sized data centre with a dozen racks, some IT equipment and basic infrastructure components. Aside from your winning personality you need a couple of aces to make your proposal stand out from the rest. What to do?

As a start, I can offer you five very simple, yet effective, strategies to show your customer how much you have invested in their solution. It’s not about product and price, but rather about adding value. It’s about efficiency, but efficiency without compromise.

1. Proper sealing

Cooling loss through floors, walls and ceilings, or the introduction of humidity from outside the critical facility, reduce cooling system efficiency. Therefore, the data centre should be isolated from the general building and outside environment as much as possible. This is the first step in any plan to increase efficiency. If the room is not properly sealed, all other measures for improving efficiency will be less effective. A data centre assessment, available through various consulting engineering firms or your cooling system supplier, can help identify areas where outside air is entering the controlled environment and recommend strategies for proper sealing.

2. Optimise airflow

Once the room is sealed, the next step is to ensure efficient air movement. The goal is to move the maximum amount of heat away from the equipment while using a minimum amount of energy. Optimising airflow requires evaluation and optimisation of rack configuration, air conditioner placement and cable management.

Further steps to optimise airflow include proper rack arrangement, computer room air conditioning placement and cable management.

3. Use economisers to achieve free cooling

In many locations, outside cool air can be used to supplement data centre cooling and provide "free cooling” during colder months. This is accomplished through the use of economiser systems. A recent study on building control systems found that, on average, the normalised heating and cooling Energy Use Intensity (EUI) of buildings with economisers was 13% lower than those without economisers.

There are two basic types of economiser systems: air-side economisers and fluid-side economisers. Choosing the type for a specific project depends on climate, codes, performance and preference.

4. Increase the efficiency of room air conditioners

Three factors are critical to optimising the efficiency of Computer Room Air Conditioning units: how efficiently the units operate at partial load, how efficiently the units are at removing sensible heat as compared to latent heat, and how well multiple units work together.

5. Deploy supplemental cooling

Supplemental cooling is a relatively new approach to data centre cooling. Over the years, raised-floor cooling proved an effective approach to data centre environmental management; however, as rack densities exceed 5kW, and load diversity across the room increases, supplemental cooling should be evaluated for its impact on cooling system performance and efficiency.

At higher densities, equipment in the bottom of the rack may consume so much cold air that remaining quantities of cold air are insufficient to cool equipment at the top of the rack. The height of the raised floor creates a physical limitation on the volume of air that can be distributed into the room, so adding additional room air conditioners may not solve the problem.

Keep it cool

Data centre cooling represents a significant opportunity for improving efficiency. As a reseller – and trusted advisor – it also represents one of the biggest opportunities to demonstrate the value of your service to your customers.

In many cases, relatively simple and inexpensive changes, such as improving room sealing, moving cables or other objects that obstruct airflow or installing blanking panels, can pay immediate dividends. In addition, new technologies, such as variable capacity room air conditioners and sophisticated control systems, should be considered for their impact on efficiency.

Finally, supplemental cooling systems provide a response to increased equipment densities that can increase the scalability of existing cooling systems, and keep the data centre efficiently cool without compromising its essential functionality, availability or power.

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