A Simplified, Pragmatic Method for Determining Cost Effectiveness of UPS, Battery and Flywheel Alternatives

摘要

Specifying UPS systems today can be a true nightmare. 'Line Interactive', 'Double Conversion', 'Continuous Power', etc., etc - the marketing never seems to stop. The choice between DC alternatives such as wet batteries, sealed batteries, or flywheels is confusing enough. The author presents a performance-based approach for filtering out the hype and determining the right system for your particular application. The method is simpler than most, yet marries relevant practical performance criteria to real world cost concerns. After establishing your mandatory specification minimums for qualification, and both installation and basic operating cost issues, a weighting system processes the vendor-to-vendor differences in dynamic performance and site compatibility issues. Owners and their engineers change weighting as suits their particular application. For example, electrical efficiency weighs heavily at 23 cents per kWhr, but very lightly at 3 cents per kWhr. Upon completion of the comparison matrix, weighing factors are applied to bid prices and the decision is made. The primary objective of this paper is to provide a tool to the average critical power buyer for comparing the cost-effectiveness of dissimilar UPS technologies for specific applications. This is impractical if not impossible with conventional construction specifications. A secondary objective is to remove some confusion and perhaps a few myths normally associated with some construction specs.