Determine if Uninterruptible Power Supply UPS is Affordable

Electronics, Instrumentation & Electrical Database

Continued from:

• Determine if the selected UPS is maintainable.
  • of Selecting and designing a Uninterruptible Power Supply UPS

Evaluate if Uninterruptible Power Supply UPS is affordable: Although discussed as the last step in the selection process, affordability is often a limiting factor in the selection of an UPS. It is placed last because the pricing of the UPS can only be done when the type, configuration, and sizing are known. When considering the cost of an Uninterruptible Power Supply UPS (or any product, for that matter), it is best to consider the total cost, or life cycle cost, that will be incurred. For a UPS, the total cost includes the purchase price, installation cost, operating and support costs, and disposal costs. The acquisition and installation of the UPS typically constitute the greatest portion of the life cycle cost. A static UPS will cost between $100 and $250,000 while the cost of a rotary ranges between $5000 and $1,000,000 for single units. The cost of any needed auxiliary equipment must also be considered. At a minimum, a manual bypass switch is required to disengage the UPS from the input power and load during maintenance or repair. These switches are typically integrated into a static UPS but are standalone items with rotaries. In the latter case, the switches require additional cabling and support hardware. More sophisticated systems having automatic monitoring, switching, and control functions requiring additional components, adding to the complexity and cost of the system(s). As part of the installation costs, the costs associated with needed facility modifications should also be considered. If the UPS is operated under adverse conditions, availability will suffer. Specific precautions must be taken for dirty, hot, cold, corrosive, explosive, tropical and other adverse conditions. Additional air conditioning might be required for the UPS (or for the facility due to heat loads from the UPS). Rotary units may require additional or special ventilation equipment to purge toxic fumes from working areas. Floor units (usually static UPS for computer system backup) may require strengthening of the floor to support their weight. Large UPSs may require the construction of a separate building to house the unit. A rotary UPS or engine generator used in a cold climate will probably require thermostatically controlled lubricating oil, coolant heaters, and radiator louvers. All equipment manufacturers specify the temperature extremes, humidity, and other conditions for which the UPS was designed. Operating and support costs of the UPS are usually secondary to the costs of purchasing and installation. However, they can be substantial and should be included as a factor in the final selection. Operating and support costs include cost of fuel, maintenance, replacement parts, and taxes. Finally, when an UPS reaches the end of its life, disposal costs will be incurred. Disposal may simply consist of dismantling the UPS and selling the parts to a recycling company or dumping it at an approved refuse site. For UPSs containing dangerous or environmentally unsafe chemicals or materials, disposal is much more complicated and expensive. For example, disposal of lead acid batteries must be performed according to all federal, state, and local regulations. Lead-acid batteries should be reclaimed to avoid the regulatory requirements for hazardous waste treatment and disposal facilities. Reclamation may be included as part of a procurement contract for replacement batteries or contracts may be placed with a permitted reclaiming facility. In disposing of spent batteries, the facility manager must ensure that batteries meet all radioactive contamination requirements for uncontrolled release. A variety of UPS types and configurations can be selected. The costs can vary widely depending on the specific type and configuration selected. It is impractical to provide an all-inclusive cost comparison of all possible combinations of types and configurations.

References: “Joint Departments of the Army, Uninterruptible Power Supply System Selection, Installation, and Maintenance for Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR) Facilities, 31 May 2002.”