Energy Efficiency

Mitchell Lewis & Staver strives to provide energy efficient products that not only saves money for our customers but also benefits our environment. We will work with you to asses your needs and map out a plan to ensure that you get the best results possible. Here is one example of how we helped a customer save money and reduce the use of energy needed to maintain their equipment.

A small barley farmer was using a fixed speed pump to provide irrigation water to his acreage.  The pump was started by using across the line voltage.  During startup, the pump motor drew up to 4 times its normal running current.  The customer was charged based on this instantaneous start up current from the local utility company, not the running current.  Mitchell Lewis & Staver Co. was brought in to assess the situation and provide a more economical and reliable mean of providing water.

Having numerous years of expertise in the irrigation industry, Mitchell Lewis & Staver recommended using a Variable Frequency Drive (VFD) instead of the standard On/Off positions of the pump and a water line pressure switch.  A VFD will adjust the frequency of the power supply from 60Hz to something lower and back up to full speed as demand changes.  During startup of the pump, the VFD slowly brought up the pump speed, never exceeding the current rating of the pump’s motor.  As the line filled with water, the pressure switch signaled back to the VFD to adjust pump speed accordingly to maintain a predetermined set point.  As more wheels were turned on, the pump was sped up, as wheels were shut down, the pump slowed down.  The pressure switch/VFD combination could also turn the pump on and off as needed.  As an additional benefit, the slow ramping of pump speed and line pressure, reduced wear on the pump, motor and mechanical line components (water hammer).

After several weeks in use, it was calculated that the VFD/pressure switch combination produced an annual savings of $12.00/acre.  Typical sized farms can range from 4000-6000 acres in size, resulting in net savings of $48,000-$60,000 per year.  Depending on the systems needs and equipment provided, the cost cutting opportunities could be ever greater.