Design of Power system for a Data Center
A data center with the dimension of 40ft Long x 30ft Wide x12ft High is located on the 12th floor of a high rise building in downtown Chicago, IL. The data center must operate all the time regardless of the availability of power from the utility. The loads can be categorized as high, medium and low critical. Table 1 shows the power rating of each cabinet and the critical level of each load. The cabinets are 12-ft wide x 6-ft High x 2-ft deep. Four of these cabinets must be strategically placed in the room to obtain the best heat exchange at minimum cost. The cooling registers are located on the floor and the exhaust registers are placed on the ceiling as shown in Figure 1. The cooling cost per BTU is $0.01. Each cabinet generates 30,000 BTU per hour and heat must be removed to operate properly. The cost of electricity is $0.1 per kilowatt-hour. Exhaust fan can help to remove heat faster. A 1000 cfm require a 1 hp motor.
Each highly critical load must be supported by 5 sources of power; such as one utility, 2 UPS and two generators.
Medium critical loads require utility, UPS and two generators.
Low critical loads require utility, UPS and a generator.
Select the sizes for of the two generators to provide power to the racks as well as cooling for High and Medium Critical loads.
The UPS must be able to withstand 20 minutes for Medium and low and 1 hour for High Critical Loads.
Determine the depth of Discharge and battery sizes and type using Table 2 information.
UPS costs $750.00/Kw for 20 minutes operation.
UPS costs $2500/kW for 1 hour operation.
Generator Costs $1000/KW.
Deliverables:
- Provide a drawing to show the location of each load in the cabinet to obtain proper cooling for each load at lowest cost and risk
- Provide a drawing for the cabinet layout
- Determine the size of cooling system (BTU)
- Calculate the size exhaust fans (CFM, hp)
- Provide the UPS size
- Calculate the Battery size and type in the UPS system
- Determine the Generator size
- Calculate the Total power requirement (with 20% safety margin)
- Determine the System Efficiency
- Calculate Total Cost of Cooling, UPS and Generators.
Table-1 Load per Cabinet
20 kW High Critical |
20 kW High Critical |
10 kW Medium Critical |
15 kW Medium Critical |
30 kW Low Critical |
30 kW Low Critical |
Table-2 Battery Information
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Figure-1 Data Center Cabinet Layout for Cooling