Download Determining Kilowatt Capacity of Data Center Space

 Determining Kilowatt Capacity of Data Center Space If the space has a dedicated Primary UPS module: 1. Determine the rating of the primary (non‐redundant) UPS unit(s) serving the space. If the unit(s) is rated in kW, this value should be used in calculating the number of kilowatts provided. 2. If the unit is rated in kVa (most battery‐backed UPS), this number must be multiplied by the power factor to determine kW. Common power factors are between .8 and .9. If spaces share Primary UPS power, but have dedicated Power Distribution Units (PDUs) It is common practice to “oversubscribe” UPS, by connecting more PDU load than could be supported by the UPS if all PDUs were simultaneously loaded to capacity. Because of this, additional investigation is required to determine the actual kW committed to a space. 1. Determine the rating of the primary UPS serving the space per the section above. 2. Determine the capacity of all primary (non‐redundant) PDUs served by the primary UPS. Insure that the final PDU configuration is used (no additional units will be added). 3. Determine the capacity of the dedicated primary PDUs for the space in question. 4. Divide the dedicated PDU capacity (#3) by the overall PDU capacity (#2) and multiply by the primary UPS capacity (#1) to determine the kilowatt capacity of the space. If space or rack share PDU power 1. This scenario is usually by‐the‐circuit. Capacity should be determined using the PDU or remote power panel (RPP) output breaker size for each primary (non‐redundant) circuit. 2. Output breakers can only be loaded to 80% of rating. Thus, a 20amp breaker provides 16amps of power. 3. For single phase circuits, multiply voltage x amps x .8 to determine watts For three phase circuits, multiply voltage x amps x 1.732 x .8 to determine watts Notes: 1. Always determine kilowatt capacity using only the primary electrical system components (UPS, PDU or RPP). Cost for the redundant capacity should not be included. Different costs per kilowatt are largely dependent on the topography (N, N+1, 2N) used. 2. Always use kW when completing calculations. Any capacities listed as kVa must be converted utilizing the power factor. 3. If distributed‐redundant PDUs are used rather than 2N in a shared UPS environment, the overall electrical distribution must be analyzed to determine the primary PDU loads. 4. 1kilowatt = 1,000watts