Ask An Expert
Dan Fanning - LEED AP,
DC CEP, HCC
Projects & Engineering Manager – EDI, Ltd.
Dan has spent over 15 years as a general contractor and project manager in critical environments, incorporating the telecommunications, construction, and electrical and mechanical industries. His work includes complete project lifecycle management, equipment installation, and resource administration. Dan also designs and builds data centers, implementing evolving industry trends and technologies, as well as cost conscious performance strategies. Dan manages EDI’s Data Center Services Division’s general contractor licensing, primary design, cost modeling, and construction services.
Recently, Dan completed the US Department of Energy pilot Data Center Energy Practitioner Program (DCEP – established in 2010). Participation in this pilot program is by invitation only. Dan is now one of an anticipated 200 practitioners to be certified under this program by the end of 2011. As a Level I Practitioner, Dan is qualified to evaluate the energy status and efficiency opportunities in data centers under this new program. The key objective of the DCEP is to accelerate energy savings and reduce environmental emissions in the dynamic and energy-intensive data center marketplace.
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Q: How do I determine the cost of my mechanical unit's operation? I have five 15-ton air-cooled units.
A: To get it just right we would need to know the condenser model and your utility rate. The type of humidification and reheat will affect this number as well. Let’s assume the condenser is a basic CDF205 unit. First, we determine the electrical requirement for both the CRAC and CU using the product catalog or website - 36.1kW. Then, we determine the annual kilowatt-hours (kWh) - 36.1 * 8760 (hours in a year) = 316,236 * 5 (the number of units) = 1,581,180 total kWh. Next, you will need to look on your utility bill to get your kWh charge; don’t forget to include any taxes or fees. Assuming a utility rate of 7 cents per kWh, the total kWh cost would be 1,581,180 * .07 = $110,682.60 per year.
Q: I need to figure out how many BTUs are being produced in my racks. How do I do that?
A: If name plate BTU data is not available there is an easy rule of thumb you can use. First, you need to know the cabinet load. Let’s assume your cabinets are 5kW each - 5kW = 5,000 watts. 5,000 x 3.414= 17,070 BTUs. To convert to tons, another rule of thumb is to divide by 12,000. 17,070 / 12,000 = 1.4 tons per cabinet. These rules do not account for altitude or high ambient temperatures.
Q: Upper management does not support my request for under-raised floor cleaning. How important is it?
A: In short, very important. We assume you are using your raised floor as a supply air plenum. It is standard industry practice to have under floor cleaning as part of a scheduled maintenance plan. Any contaminates under the floor will be blown around in the plenum and can make their way into the critical server or storage equipment, which can affect performance or reduce equipment life cycle.
Q: We have an older data center and seem to run a gamut of problems when we add equipment. In particular, we have a low drop ceiling. I have maintained that this is affecting our mechanical performance. Would you agree?
A: That could very well be the case. I would need to know more about the symptoms your data center is experiencing, supply and return air paths, and just how low the ceiling is. But in general, a low ceiling makes for a less than optimum environment. If the opportunity is there to utilize the drop ceiling as a return air plenum, I would definitely look into that. Typically, this is a low price modification that will greatly increase your mechanical efficiency and flexibility.
Q: We have a newer data center with redundant UPS, generators, and FM-200. After an accidental FM-200 discharge, we are looking into different fire systems. What do you suggest?
A: You are not alone. The industry is turning away from clean agent where it is not necessary for this exact reason. We recommend an aspirating smoke detection system in conjunction with a normal fire detection system, coupled with a double interlock, pre-action sprinkler system. The aspirating smoke detection provides early warning, and if zoned properly, can lead you to the area of the source. This area can then be inspected and treated with FE-36 type hand-held fire extinguishers, if necessary. Don’t forget to have your installer include a reference detector to help prevent nuisance alarms.