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Power Factor Correction: Not Snake Oil
My buddy working for Bonneville Power Administration for nearly 30 years and I got together earlier this summer for some R&R in Montana. The authors of Reducing Power Factor Costs (Bonneville Power Administration) explain power factor correction with the illustration of a horse pulling a railroad car down a railroad track. If the horse can pull the railcar straight without veering to the left or to the right, then achieving a "power factor" of 1.0 is ideal -equate this to efficiency. While riding some huge beasts through Glacier National Park with my buddy, I was mindful of the horse carrying me near the roaring waters of a glacial river and what the guide told us about the few minutes of expected survival time for those falling into the chilling rivers or lakes within the park. I remained hopeful that my horse would stay parallel to the river and walk a straight and narrow path - equate this to blind trust.
Either the publicly traded companies Fluke, Power-Save Company and the research from Bonneville Power Administration are all wrong as the skeptics maintain, or as I believe, the same skeptics are shooting from the hip with bad information.
With 1.0 power factor being a high goal, I knew several months ago that our building is or should be pretty efficient. I also knew about every penny being spent on improvements and what projects including construction of our new space involved. What I didn't have were metrics taken from the main panel revealing the energy savings to qualify the performance of the capacitors we procured from Power-Save. I did know that we (my offices and a technician's home) enjoyed an 18/17 percent reduction in billable kilowatt-hours. Previously, I conducted a brief phone interview of another user of the same gear from Frederick County Public Schools and noted that they already performed the same exercises I was about to have done. The exercise of pulling the panel cover off and connecting the probes of the Fluke 1735 was a drill that I put the electrician through more than once.
Here's what we found:
With the Power-Save 1200 unit powered off (dedicated breaker) and the HVAC running; Leg 1 draw 3.1 kilovolt amps (KVA) with a Power Factor of .936; Leg 2 draw 3.0 KVA with a Power Factor of .911
With the Power-Save 1200 unit powered on and the HVAC running; Leg 1 draw 3.0 kilovolt amps (KVA) with a Power Factor of .994; Leg 2 draw 2.8 KVA with a Power Factor of .974
So on Leg 1 we are using .1 KVA less current and the Power Factor improves .058 to .994; on Leg 2 we are using .2 KVA less current and the Power Factor improves .063 to a Power Factor of .974 This is just one system and not all the components that include fans, pumps, motors, and compressors. All of which are found in the data center.
The science of power factor correction is true. The capacitors reduce the drawn amperage used by fans, pumps, motors, compressors or anything with an inductive load. Less amps consumed equate to savings in what the utility company bills (they bill in kilowatt hours). While the amperage is reduced slightly, remember that how long the devices run (time or kilowatt hours) is what racks up the charges on the bills. It is still important to also remember that the candidates for power factor correction will have motors, pumps, fans, and compressors and aged gear over 10 years. Power Factor correction works in residences, businesses and any place using 200 amp single phase or 200/400 amp three phase services that have any of this gear.
The payback on my unit is around 2 years while my tech's is about 15 months because his kilowatt-hour (KWH) rate is higher, around .146 per KWH (BG&E) vs. mine, which is .09 per KHW (Allegheny Power). Power factor efficiency is still really a snapshot of a specific system (such as our HVAC) operating. It is possible to isolate most of the gear and turn off (breakers) to all other gear then measure each system or gear separately. Time is better spent by inventorying what gear is used on which panels along with the age of the gear to qualify each panel for the expense of power factor correction.
There's an old saying about putting your faith into something is different than putting it on something. The horse I rode in Montana, aptly named Rock, is a Friesian breed that I did put my trust, blindly on. I endured no harm and knew he is in control. Earlier, I relied in the research of many others far more qualified in power and power correction.
I am not only depending upon the scientific evidence that Fluke published in a case study of their own, but having seen the results taken from my site with the 1735 attached with its numerous umbilical cords tied to my electrical panel recording every detail. The local rep and tech support engineer from Fluke previously assisted my electrician, who is my buddy too, that I've known for many years. Months earlier, we both had doubts about this gear advertising that power factor correction saves money. So we installed the box, made no additional energy saving changes and continued to monitor the next 4 months of billing to validate the savings.
Power Factor correction improves the efficiency of gear operating within your electrical distribution systems not the utility companies'. The Power-Save capacitor does reduce cost by reducing amperage or current drawn and used for any device using an inductive load (motors, pumps, fans and compressors). These devices generate less heat and the capacitor unit acts as a primary TVSS (Transient Voltage Surge Suppression) system.
All the experts lined up to show me that in one snapshot, for one example given, that power factor correction is possible and works as advertised. The only thing left for me to do to appease the anonymous critics is to rub a little snake oil on. Power Factor correction results do vary and for us it proved a beneficial exercise - one of a little faith and a little science netting me a painless and reasonable ROI.