Joe Evans is responsible for customer and employee education at PumpTech, Inc., a pump & packaged system manufacturer & distributor with branches throughout the Pacific Northwest. He can be reached via his website www.pumped101.com. If there are topics that you would like to see discussed in future columns, drop him an email.
Energy consumption for a given volume of pumped fluid can be a bit perplexing. It has nothing to do with the flow rate of the pump. It involves the wire to water efficiency and head required. An increased flow rate will increase the horsepower required, but horsepower is an indication of the work performed per unit of time. A higher flow rate does more work in a shorter period of time. For example, if a 500 gallon-per-minute pump and a 1,000-gallon-per-minute pump have the same wire to water efficiency and are pumping against the same head, the energy required to pump 1,000 gallons will be the same. If the head is increased or the efficiency is lowered, its energy consumption per given volume will increase.