There are many articles about the data center and how to make it more efficient. There are fewer articles about the network closets and their efficiency. Many of the efficiency recommendations for the data center are valid for the network closet.
A major technology cost is electrical power: power to run the technology and power to cool it. Cooling IT technology can account for as much as 45% of the IT power bill. The cooler the temperature, the higher the power bill. Rising electrical rates makes it even more important to deliver cooling efficiency.
Paying Attention to Cooling
Network closet space is usually small, therefore designers tend to pack equipment densely together. This saves space but creates cooling problems. Too much in a rack and the equipment stays hot--too hot for too long. Data centers can be redesigned to be water-cooled to allow for the increased equipment density and its associated heat. This is an unlikely and expensive solution for the network closet.
The addition of Power over Ethernet (PoE) adds considerable heat due to PoE power supply in the LAN switch to operate IP phones. Another factor is the chip design in IT equipment. The faster the chip and the denser the components on the board, the hotter the equipment. So newer, smaller equipment can produce more heat per square inch then less densely designed slower equipment.
Prior to 2004, the operating temperature recommended for data centers was 72 degrees Fahrenheit. In 2008, improvements to the equipment had allowed this limit to rise to 81 degrees Fahrenheit, according to the ASHRAE Technical Committee 9.9 (American Society of Heating, Refrigerating, and Air-Conditioning Engineers). However, older equipment still requires a lower operating temperature.
Hot technology also means less reliable technology. According to the UpTime Institute, once the equipment operates at 88 degrees, reliability drops by 50%--another reason to manage cooling properly.
Recommendations for Cooling Efficiency
Each of these recommendations can be implemented separately. Some may already be in place. Others will require some investment and probably facility changes. Look at the ROI for these investments. The ROI should be profitable when you include the long term rate increases you may experience.
* Verify the highest operating temperatures that the equipment vendor recommends. Operate at that temperature, no higher, as this may negate your warranties and maintenance contracts. However running at a higher temperature that's still within the allowable range can reduce cooling costs.
* Physically inspect the rack density. Equipment may have been installed at the installer's convenience without considering the cooling requirements. This can produce hot spots that affect reliability and increase the cooling bill. Move the equipment around to balance out the heat production evenly.
* If you are located geographically where the outside temperature is below what is needed for cooling, consider economizers. By using the outside air, you reduce the cooling bill.
* If your cooling equipment is old, consider investing in more efficient systems that can monitor temperature better. The UpTime Institute has found that the average data center has 2.6 times more cooling capacity than needed. This applies to the closets as well.
* Get rid of old room humidifiers. Evaporative and atomizing humidifiers use far less energy.
* When building or rebuilding the closet, be as flexible in the configuration as possible. Flexibility will allow low-cost changes in the future that will keep up the cooling efficiency.
* Consider calling in energy design consultants who can recommend changes for cooling efficiency. This is a one-time cost that can save money for years.
* Monitor the entire space. This will help balance the cooling and reduce overcooling to compensate for hotspots. The monitoring should be in real time so that alerts can be issued when there are problems.
Cooling is an ongoing cost, and one that can be controlled. Cooling prevents problems but does not in itself produce useful work. It is like a tax. You have to pay for it, so design and operate to produce the lowest tax bill possible.
