Water Well Journal
Issue link: http://read.dmtmag.com/i/728580
present worth evaluation—for prospec- tive purchases is a logical and important analysis to conduct for an entire water system design or virtually any separate component. Beyond the obviously important technical and installation factors (design conditions, pump setting, bowl diame- ter, pump operational and cycling pa- rameters, pump curve shape), evaluating the potential payback and investment re- covery for the system and individual components such as comparing the use of a VFD to a control valve is a critical design function to perform. This will help the designer and client make in- formed judgments on a potential pur- chase well before it is actually made. The process itself is not hard to do. It may take additional time and effort to conduct these evaluations—but so too is providing the client with the most effi- cient and cost effective system. As I said, there are numerous spread- sheets and computer software programs, as well as various manual calculation methods, now available to help with performing these vital economic deter- minations and payback analyses. This type of analysis can be useful to the people paying the bill regardless of the system component—whether it is the well pump itself, choosing between water storage and multiple pumps, horsepower options, or deciding be- tween a variable frequency drive or a control valve. This type of economic analysis is used for the basic premise of whether to use one device over another for strictly the initial purchase price and power cost reasons. Other considerations should also be included in the decision-making process for using either a VFD on a VTP or submersible pump or for using a submersible pump for a deep well pumping installation over a VTP. Most of them are technical and related to motor life, electrical losses in the motor, and possible electrical currents through the motor bearings. We will cover many of these, includ- ing modifying the system design to in- clude a pair of submersible pumping units from the well, in the coming installments of The Water Works. Until next time, keep them pumping! WWJ WWJ October 2016 65 Twitter @WaterWellJournl Ed Butts, PE, CPI, is the chief engineer at 4B Engineering & Consulting, Salem, Oregon. He has more than 40 years of experience in the water well business, specializing in engineering and business management. He can be reached at epbpe@juno.com. Table 1. Well Pump Options Description Pump #1 Pump #2 Pump #4 Purchase price $15,900 $16,750 $8600 Installation cost $2000 $2000 $2000 Hours operation/day 5 5 5 Dollars/kWh (example: 0.05) $0.12 $0.12 $0.12 Motor HP 40 40 50 Pump head (feet) 225.0 (adj.) 225.0 (adj.) 225.0 (adj.) Pump flow (GPM) 156 156 156 Pump operating efficiency 54% 51% 43% BHP (brake HP) 16.41 17.38 20.61 Total energy cost/year $6177.35 $6283.07 $7732.14 Maintenance cost/year $1000 $1000 $1000 Years of service 20 20 20 Downtime losses/year $0 $0 $0 Life Cycle Cost: $161,446.97 $164,411.50 $185,242.71 Learn How to Engineer Success for Your Business Engineering Your Business: A series of articles serving as a guide to the groundwater business is a compilation of works from long- time Water Well Journal columnist Ed Butts, PE, CPI. Visit NGWA's Online Bookstore at www.NGWA.org for more information. ISO 9001 Quality System For Details on all the features of Pullmaster winches, please contact us for the name of your nearest distributor. Pullmaster Winch Corp. 8247 - 130th Street Surrey, B.C. Canada V3W 7X4 Tel: (604) 594-4444 Fax: (604) 591-7332 Email: info@pullmaster.com Website:www.pullmaster.com THINK TOUGH! S T A T E • • OO F • • TT H E • • AA R T • • HH Y D R A U L I C • • WW I N C H E S 19350-22nd Ave. Surrey, BC Canada V3Z 3S6 Tel: (604) 547 2100 Fax:(604) 547-2147 Email: sales-ca@team-twg.com Website: www.team-twg.com