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Energy costs have skyrocketed in recent years and will continue to do so as long as the nation’s power grid operates at or near capacity. Energy providers expend more and more energy just to generate the electricity that consumers demand, thus the rising energy costs. The good news for the business world is that innovations have been made in power efficiency within the data center. Businesses can take some of that money back from the utility provider and save a bundle on their utility bills by implementing these simple strategies.
Data centers are very power hungry, not a surprising fact considering the amount of tasks they can process. However, it might be a surprise as to what in the data center consumes the highest percentage of energy.
Implementing simple strategies to reduce power consumption could save your company thousands of dollars per month.
Virtualization
Computer equipment has the highest power requirements of the data center. Overall power consumption can be reduced by deploying virtual servers. A virtual environment allows a server to take on the functions of multiple servers in one machine. Each function of the separate machines operates independently on the same machine in the virtual server, ensuring no hindrances occur from each function running concurrently on the same machine. A virtual server can even have multiple operating systems running on the same machine, each in its own virtual environment and running independently of the other operating systems.
Servers are built to process much more data simultaneously using multi-core processors. In times past, it may have been necessary to have one server perform functions due to hardware limitations and, as they say, “old habits die hard.” With all this processing power built into multi-core processors, why not leverage this additional processing power?
Multi-core processors are designed to handle hardware virtualization. Virtualized servers will utilize the processing capability of your equipment resulting in fewer machines. Fewer machines means the biggest power hog of the data center, the servers themselves, will not consume as much electricity as before.
Virtualization software has continuously been improved and is available to ease the transition to a virtual processing environment for both servers and workstations. The virtualization concept is transforming the server market and already cutting into the number of machines sold. The benefits are numerous and one of the biggest is the savings on your monthly electric bill.
Efficient Cooling
With cooling being the second largest energy consumption source in the data center, it’s important to continually assess the performance of your cooling equipment. The best way to cool the data center more efficiently is to ensure the site HVAC system is doing most of the work and airflow is correct into and out of all equipment. It is essential to make sure cool air is properly flowing into the data center and all vents are unobstructed. Take the time, in quarterly intervals to check all air filters and air ducts.
Commonly, site HVAC systems have the option to add an air economizer. If this has not been installed at your site, it should be considered. Air economizers reduce the work required by the HVAC system by circulating cooler outside air to the inside. To deal with the problems associated with higher humidity levels in the cooler air, the air economizer is equipped with a humidity monitor and the HVAC system makes the proper adjustments when needed.
Taking these steps will reduce the power requirements of the second biggest energy hog in the data center and, once again, the results will be observable on the energy bill.
KNOWLEDGE NUGGETT: Expect to pay 30% more for electricity generated by a conventional air conditioner as opposed to using a CRAC unit.
Air Circulation
Air flow is the third largest source of power consumption in the data center. Air circulation in this context is the intake of cool air at the front of the server and warm air, heated by the server mechanisms, pushed out the rear server exhaust. This is accomplished in the servers by fans turning on and off when needed. Oftentimes, these fans only turn on when the server reaches a certain load capacity or a certain internal temperature.
The amount of work done by the server air flow process can be reduced simply by having an optimized layout of the servers in the data center. It is important to build and test (simulate) a hot aisle/cold aisle configuration. Doing so will ensure the highest level of air flow is promoted by the floor layout.
A hot aisle/cold aisle consists of servers placed in a front to front and rear to rear layout throughout the data center. Cooler air is taken in through the front of the machines, so having two facing server racks inherently creates a “cold aisle” of air between them. Alternatively, at the rear of the server racks is the server exhaust from which the warmer air is expelled. A “hot aisle” is created where the backsides of two server racks are facing, the warm air rises and is circulated out of the room.
The HVAC supplied air should enter the room through the floor through perforated tiles in the cold aisle for the most efficient hot aisle/cold aisle configuration. This way, inherent qualities of the cool and warm air is used to promote proper circulation – heavier, cooler air in through the floor, and lighter, warmer air out through the ceiling.
UPS (Uninterruptible Power Supply)
Data centers depend upon UPS to ensure around-the-clock uptime. Currently, backup UPS’ come in three varieties that deliver power in three different ways with some methods more efficient than others. Even though the UPS is considered a power backup to the data center, as shown above it is the fourth largest source of power consumption so attention needs to be focused on increasing UPS power efficiency.
The first type of UPS, online, is attached to the main power line. There are two different methodologies using online UPS: double conversion and delta conversion. Double conversion online UPS constantly monitors the power flow into the data center through a rectifier, charger, and inverter. AC power flowing into the data center is converted to DC and then converted back to a constant flow of AC power. This constant monitoring and converting of the power flow results in a decrease in power efficiency of 10%-20%, a sizeable amount.
Delta conversion is a much more efficient method of online UPS. Delta uses the online inverter to generate the voltage difference between the line voltage and the actual voltage to ensure a constant flow of power instead of converting all power flowing into the facility. This method greatly enhances power efficiency up to 97%, an increase of 7% to 17% over double conversion.
Line interactive UPS technologies use AC line power to charge a DC power battery during normal operating conditions. This method differs from online UPS in that the system does have to switch to battery power when needed. When power fails, the battery power is converted back to AC for use in the data center. Line interactive UPS also conditions power flow to ensure proper voltage. Using line interactive UPS results in 90%-96% power efficiency.
Offline UPS is the third method for providing backup power. There are two methods for offline UPS: standby and ferro-resonant. Standby UPS relies on a switch to transfer data center power from the AC line to a battery backup source. Typically this switch time is about 1 to 5 milliseconds and many companies can live with that. Because the inverter is mostly operating in standby mode and only in use during times of power failure, standby UPS is able to operate at 95%-97% efficiency, the highest rate among all methods of UPS.
Ferro-resonant UPS uses a ferro-resonant transformer to virtually eliminate transfer time. Otherwise it uses the same methods as standby UPS to provide a backup power source. Some power efficiency is lost but a ferro-resonant UPS still operates at 90%-93% efficiency.
Perhaps your company can make a change to a more efficient UPS method. When researching the best option, potential data loss must always be considered. For some companies, for example, a battery-switching time of 1 to 5 milliseconds would be unacceptable.
Lighting
Data center lighting is the fifth largest source of power consumption. All too often, lights are left on unnecessarily. Data center lights should only be turned on during times of human intervention and this should be kept to a minimum. That being said, the lights in the data center room should only turn on when an employee enters the room, such as when an identification card is swiped to unlock the room.
Lights generate heat, however small, but any unnecessary heat in the data center room increases work for the HVAC and server rack cooling systems. Keeping lights off keeps the HVAC system and server cooling systems operating at the highest level of efficiency.
Human interaction in the data center should be kept to a minimum. Keyboard, video, mouse (KVM) switches should be used as much as possible. These (in many cases) allow data center servers to be administered from another location, outside the room where the servers are located.
Questions every business decision maker should ask:
1. Am I using virtualization technology to improve redundancy and reduce energy consumption?
2. Is the HVAC optimized and does my staff conduct maintenance on the filtration system in scheduled time intervals?
3. Do I have my server racks laid out correctly in a hot aisle/cold aisle configuration in the data center?
4. Could I use a more efficient UPS and/or make improvements to my current power backup system?
5. Am I using the correct lighting system in the data center and KVM equipment to manage all the data center equipment?
Correct answers will offer insight to what options your business can take to save money on electric bills. By taking advantage of some or all of these power-saving innovations, your company will see considerable savings each month due to reduced power consumption in the data center.
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