Issue 4, June 2009
FOCUS POWER & COOLING
“Many data center managers don’t know the efficiency of their IT equipment or site infrastructure – or have a clear path in mind for maintaining and improving that efficiency. There is a lot of low-hanging fruit being overlooked, easy opportunities to reduce energy costs and become “greener” in the process”
Q: Compared to diesel generators and lead acid batteries, fuel cells provide better efficiency, reliability, service life, lower maintenance cost and emissions, while running quietly. What research have you done on fuel cells, and do you foresee this technology playing a key role in the sector in the near future?
A: The biggest barrier to fuel cell adoption today is the very high initial cost, compared with traditional backup energy sources. Most organisations have a hard time making a business case for the premium price, especially when existing solutions are still satisfactory.
However, we will see changes in the next five years or so, due to several forces. Increasing concern about environmental issues shines a harsh light on the dark side of traditional technologies: dependence on fossil fuels; emissions from diesel generators; and disposal of lead-based batteries. When we start to see greater tax benefits for green operations (and lower prices for maturing fuel cell technology), the technology will have to grow. Companies that seek the environmentally-conscious path will drive adoption of fuel cells, more than the experimental level of today.
At Eaton Power, we believe fuel cells represent an exciting potential for our customers. We continue to track trends in the industry, and we are working with a number of technology providers with an eye toward offering a commercially viable fuel cell offering as soon as practicable.
Q: Do you see data centers accelerating their technology refresh cycles to achieve the advantages of virtualisation sooner? What is the best strategy in order to plan for this change?
A: There is no doubt that virtualisation can be a good deal. Some analysts predict that virtualisation will improve server utilisation for a typical x86 machine from 10 to 20% to at least 50 to 60% in the next three to five years. One of our customers found the opportunity to reduce its portfolio of 1,000 servers to about 200 servers. Even if we assumed a utility rate of only 10 cents a kilowatt-hour, this customer stands to save $700,000 (£457,000) in the first year alone.
The prospect of such savings will drive more data centers to adopt virtualisation strategies in one degree or another – and that would translate into an accelerated pace of server replacement. But virtualisation will not be the salvation for everyone. Many data centers have to be designed to accommodate periodic peak loads far above daily loads, such as seasonal peak volumes for a retailer. In that case, having under-utilised or idle hardware sitting around is just par for the course. Virtualisation wouldn’t buy this data center much, if anything. The best strategy is therefore not a prescription but a process: stay abreast of new technology developments and regularly assess the ROI potential of replacing old technology. The business case will differ for every customer, geography and infrastructure.
Q: With power and heat rising higher in blade server racks – from one kW in 2000 to 14 kW and even 24 kW today – what are your thoughts about refrigerant-based cooling systems that provide up to 30 kW cooling per rack?
A: As much as 30 to 60% of the data center utility bill goes to support cooling systems. If that figure seems too high, it is. As data center managers struggle to reduce this burden, they have to weigh several variables. Are you better off paying the higher initial cost of refrigerant-based cooling modules (and enjoying lower energy costs over time), or spreading the IT load so average power level is less than 15 kW per rack, which can be supported with conventional air cooling (no new investment necessary)?
As with so many issues in data center design, the answer is, ‘It depends’. Where existing air cooling seems to be ineffective, we are often finding that the cooling system has been inefficiently deployed, or racks are set up in a way that produces hot spots. These issues can be minimised by best practices, such as distributing servers across more racks, alternating hot and cool racks or aisles, and carefully regulating air flow across the data center.
However, in areas of the country where energy and real estate costs are high, such as in Manhattan or California, a data center could more easily cost-justify refrigerant-based cooling. The higher initial investment would be repaid in lower utility bills for cooling systems and lower real estate costs, thanks to the ability to deploy more IT equipment in the same square footage.
Q: Power cost and energy usage can be reduced with simple solutions, such as only buying equipment with internal power supplies that are at least 80% efficient. How prevalent is this practice in the data center community?
A: Even a small data center can save tens of thousands of dollars simply by making wise choices in management practices, IT hardware, power and cooling infrastructure. For example, the three-year utility savings from an energy-efficient server can nearly equal the cost of the server itself. Couple this strategy with energy-efficient power and cooling systems, and a mid-sized data center with 1,500 servers could save millions of dollars, while reducing its carbon footprint.
Unfortunately, this issue isn’t getting serious attention yet. When selecting new hardware, buyers still tend to look more closely at initial purchase price than long-term operating costs. Now that high-profile organisations such as Google have announced energy- conscious choices in their data centers, we are seeing more interest.
Let’s hope power issues don’t have to reach crisis proportions before energy efficiency moves to the forefront of every planner’s agenda.
www.datacenterdynamics.com 45
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