The importance of energy efficiency in today’s data centers has grown significantly and has become more complex in recent years. To maintain high data availability, all components of the data center infrastructure must perform the assigned tasks to avoid any data center downtime requiring appropriate energy support. The technical infrastructure is fundamental to all information technology (IT) infrastructures and it includes power supplies, technical coolers, and technical security. Any downtime value of the physical infrastructure, no matter how low, has an essential impact on the IT service performance. In general, for every watt your computer equipment uses, data centers require more than two watts of power. Think of this case, which will really say you the importance of having the most efficient data centers.

In my previous article, we have seen the different methods to calculate the efficiency of a data center. Don’t you want to know how can we achieve better PUE, DCiE, CUE and WUE by improving the efficiency of the data center? In the data center realm, maximizing the energy efficiency without impacting the reliability should be the goal of virtually every data center owner or operator. The path to that goal involves some basic design and practice issues, as well as more sophisticated methodologies. In order to achieve the goal of efficiency, you need to understand five major areas which are having a major influence on defining DC efficiency. Understanding these details in depth will give you all the better ideas to avoid any of these circumstances which will help us to make a better decision. These areas are as below,

• Factors that Impact Efficiency
• Power Systems Efficiency
• Cooling Systems Efficiency
• IT Systems Efficiency

Factors that Impact Data Center Energy Efficiency

I would say, the factors that affect the DC efficiency is one of the foremost consideration you should have from the initial thought of building a new data center. If you have the question of why? Having the idea of the below factors will give you a better understanding of this.

1. Site Location

Selecting a site location that is physically secure and has reliable access to power, water, and communications is an important first step. Moreover with the rising awareness of “free cooling” The average and highest temperatures (as well as humidity) will directly impact the energy efficiency of the cooling systems. Of course, while not directly related to the facility energy efficiency per se, attention to the cost of power and its fuel source should not be overlooked. Energy costs are highly location dependent and are based on local or purchased power generation costs (related to fuel types or sustainable sources such as, hydro, wind or solar), as well as any state and local taxes (or tax incentives) incentives which can provide lower costs, energy efficiency rebates or tax benefits.

For example, when you are having a multi-national company and need to build a data center for your operations. One of your major considerations would be to have it in Europe/America than in the Middle East where you can utilize efficient cooling methods such as ‘free cooling’ and ‘evaporated cooling’. Isn’t it making sense for having a better site selection?

2. Facility Occupancy and Power Loading Rate – Design vs. Actual

The energy efficiency of any data center will be directly affected by the actual percentage of the design load being used. The lower the load utilization compared to its design maximum, the lower the efficiency. This is directly related to its occupancy rate. If the site will not be heavily occupied for the first several years, a modular design should be considered to mitigate the impact of under-utilization. In addition, most data centers never operate 100% of design load capacity primarily for ensuring equipment reliability and maintaining uptime. Depending on the organization culture, typically systems are operated at no more than 80-85% of design ratings (some may push to 90%) before it is considered “full”. This is a necessary, but prudent compromise of reliability vs. energy efficiency.

3. Oversize Design Capacity Impacts Efficiency

 When deciding on the design capacity of the data center, there are many competing factors that influences the decisions. The fear of making it too small and running out of space or power in only a few years is a very realistic scenario and fear. In recent years the growth in computing power demands and power density has made many data centers that were built less than 10 years ago functionally obsolete, a real risk of then looking for additional space or power that is not readily resolvable with a dedicated single site. Conversely, over-sizing will mitigate that risk, but decrease energy efficiency.

4. Modular Design

 One method to mitigate the potential of over or under-sized data centers is modular design. Capacity planning and modular capacity designs can help mitigate the risk of capacity or functional obsolescence. In some designs, the total space and utility capacity is designed and built up front, but only individual sections are fully outfitted with the UPS, generators and cooling equipment. This saves both upfront capital costs and recurring maintenance expenses. Moreover, it also helps improve energy efficiency at each stage, since the smaller sections are more fully occupied and operate at a higher efficiency. This modular design still allows for planned expansion, without the energy efficiency penalty of under-utilization.

5. Proper and Continuous Maintenance

Regardless of how well designed and built, the equipment must be maintained for proper operation. In the past, this was mostly driven by the need to ensure reliability to avoid system failure. Today, while this is still the key requirement, ensure optimum energy efficiency is also part of the maintenance goals. This is particularly true for cooling systems, whose efficiency and effectiveness falls off rapidly if filters become clogged and cooling towers are not rigorously cleaned, as well as other required maintenance and system optimization for changing internal heat loads and external ambient weather conditions.

6. Power Density

 Power density is a reflection of how much computing equipment can be placed in each rack. A data center with a lower power density would mean that you may need to use more racks (and white space) to house the same amount of computing equipment than at a higher density site. Power density is typically expressed in two ways; watts per square foot or Kilowatts (kW) per rack, or sometimes both. This is primarily based on the design and type of data center cooling system. Many older data centers cannot effectively or efficiently cool more than 5 kW per rack (some even less), and in some cases, their energy efficiency goes down beyond 3 kW per rack. Even today, not all newer data centers can accommodate medium (5–10kW per rack) or “high-density” racks which require 10 kW or more per rack.

So we have discussed some of the factors that are involved in data center efficiency. But that’s not the end and we should understand what are the energy efficiency methods involved in power, cooling, IT and facility areas too. Don’t miss out on those articles too.

Knowledge Credits: Datacenterknowledge.com

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