Domestic Water Pump Cost Analysis;

ModernControls recently completed a proposal to upgrade a failing domestic water pump system for a Wilmington High-rise. The existing system has a primary pump with a hydraulic fluid mechanically operated unloader system to relieve pressure during periods of low or no demand. The motor however runs continuously. The backup emergency use only pump has a hand valve that is set to bypass water from supply to return to maintain water pressure. Neither assembly is very efficient and so both run near rated amp draw.

Our research began with the initial visit to the site to gather information. The second trip to the site was more clearly defined with the help of the product representative’s knowledge and experience with the product line.  We initially planned to install a pump package but found the physical constraints within the mechanical room too restrictive. We put the equipment package together with the product representative supplying the pump and us supplying the rest. A third visit to the site was not necessary to complete the proposal, however a third visit is planned to meet with the board members to explain the proposed equipment and how the replacement work would be scheduled to eliminate down time.

The pump manufactures representative found a 5 horse power pump that could provide the same results as the 7.5 horse power pump so we’re able to provide an initial cost savings by reducing the horse power by ⅓. The installation of a Johnson Controls variable speed drive and Metasys digital controls brings the projected cost savings to somewhere between 60% and 75%. The projected payback period for the installation is between 5 and 6 years, not bad for a necessary upgrade. With the focus today on green technology the availability of information to project cost savings gets better all the time. The projected cost savings calculation sheet used for this analysis accounted for the change in peak demand after the first year since this customer electric bill is based on a peak demand rate. If you’re wondering how much you could save by making changes, chances are someone already came up with a way to quantify it.