For the high-density facility (400 cabinets in a room with 10,000 square feet of raised floor), the total annual cost savings was $137,395 and payback occurred in the second month. Because 29.5 percent of the CRAC units were placed on inactive standby, there was a 29 percent reduction in annual operating and maintenance costs. With the recaptured cooling capacity, datacenter managers can increase server density and defer capital costs, all while reducing operating expenses.
In the lower-density facility, with 12 water-cooled CRAC units and 7.5 hp fan motors, the total annual cost savings was $30,594, and payback occurred in the fourth month. This represents a 15 percent reduction in the annual operating and maintenance costs of the cooling units.
4. Tune the computer room
After installing the recommended sealing technology, it's critical to re-examine the heat load and all cooling unit settings to ensure you have taken advantage of all the efficiencies afforded by sealing openings that once permitted conditioned air to escape or hot exhaust air to circulate.
The computer room should also be evaluated for other opportunities to increase equipment reliability and further reduce operating cost. This requires an on-site investigation by an engineer who will physically open up the equipment and make detailed performance measurements. The engineer should:
* Determine the heat load by adding together all of the PDU or Remote Power Panel (RPP) outputs or by summing the UPS system(s) outputs.
* Evaluate the configuration of the cooling units on the raised floor by checking temperature and relative humidity set points and sensitivities. Are they at the correct setting and are they consistent throughout the room?
* Check the calibration of the return-air sensors. A key factor is to ensure that the instrument being used to monitor the calibration is properly calibrated.
* Check each cooling unit to verify if it is delivering its rated cooling capacity. Both airflow volume and temperature drop need to be measured to determine the delivered cooling capacity.
* Determine the required number of operational cooling units from the heat load data and the cooling capacity information. There should be redundant cooling capacity in every area of the room.
* Determine the proper number and placement of perforated tiles. Their arrangement must be adjusted within the cold aisle based on careful monitoring of IT equipment air-intake temperatures.
* Use an infrared camera to identify airflow circulation patterns and equipment performance issues and the options for improvement.
Driving energy consumption down means costs go down. Expert computer room remediation strategies provide near-instant energy savings, which in turn make it possible to increase server density without adding cooling infrastructure. Recommendations will likely include an investment in sealing technology and ongoing temperature and environmental monitoring, but the money and time spent will pay you back in significant energy savings.
Strong is professional engineer and senior consultant with Upsite Technologies and has been with the company since its inception in 2001.