The term, "Booster Station" technically applies to any system with multiple pumps connected to a common suction and discharge header. Although PTS has extensive experience with most all types of multi-pump booster systems, specific expertise has been acquired with high pressure skid mounted booster pumping systems used for domestic water distribution systems required for multi-story, high rise buildings, typically required for buildings with five floors and higher. Depending on the type, size and height of the building, the motor HP may exceed over 100 BHP for each pump, with annual electrical operating costs easily in excess of $15,000/year.
After analyzing several older stations using constant speed motors and pressure control valves (PCV/PRV), which was typical for most all stations installed before 2000, it was determined that the pumps were grossly oversized for both the actual required flows and pressures. This "trade secret" was identified by data logging the actual flow with a clamp on, ultra-sonic flow meter over a (7) day period at (1) minute intervals (10,080 data points). By properly selecting the "right sized" pump operating with a VFD, the required motor HP can typically be reduced by +50%, resulting with annual energy savings in excess of +75%!
The secret for obtaining optimum energy savings is to identify the "actual" required flows and pressures for properly selecting the "right sized pump". If the maximum system flow rate is at or near the maximum flow for the pump (run-out), then the pump with a VFD can run at a lower RPM, with significantly lower electrical power input when operating at the lower flow conditions, which is the majority of the time. Properly programming the Start-Stop pressures, time delays (control logic) with one or multiple pumps and selecting the proper bladder tank set up, if appropriate, for the specific application is also required for optimum results.
The shortest payback of less than 12-18 months, with the best ROI, is to just replace or add one right sized pump, with a VFD to the existing station. If the station is nearing the end of it's service life, a complete replacement skid may be necessary, using multiple right sized pumps, with VFDs and touch screen controller for flexibility and easy programming, optimized for maximum energy savings. Refer to the "Upgrade or Replacement Options" for more details regarding which option may be best for a given situation.
With applicable rebates from your local electrical utility, the cost of an on site study can be offset by as much as 75%. Additional rebates are also available if the study recommendations are implemented. Go to "Rebates" page for additional information.
UPGRADE OR REPLACE?
Upgrade with One Replacement Pump
Replacing one of three existing pumps with a right sized pump, operating with a VFD and a P.E motor, integrated into the existing controller and skid usually provides the best economic return. This pump now becomes the primary, with the existing pump(s) operating as they normally do, as a backup to the primary in case of a pump failure or insufficient flow. The VFD now controls the auto ON-OFF and speed for a constant discharge system pressure. The existing controller is basically unchanged, operating the same as before, including the normal alarms and fault protection.
Upgrade with One Additional Pump
With an existing two pump station, adding one additional right sized pump as the new primary, operating with a VFD and a P.E. motor should be considered. The new pump would be mounted next to the existing skid and tapped into both the suction and discharge header. The VFD would be programmed to operate completely independent of the existing pumps and controller. Low suction pressure and high discharge pressure protection and alarms should also be considered. The existing system would now operate as it normally would, but in the standby mode only, as a backup to primary in case of a pump failure or insufficient flow.
Replace Complete Booster Station
Replacing the complete station should be considered if it is at or near the end of its service life. The replacement cost for a new, very efficient station vs expensive repair costs for an inefficient system is now the best option.
Three, right sized pumps at 50% of rated capacity, with VFDs and P.E motors, all controlled by a very flexible, easy to program, touch screen control panel with all the required fault and alarm protection included will not only provide peace of mind, but also the best ROI over the long haul. Consideration prior to purchasing and installation is required to ensure that the skid can be transported through the access opening to the pump room and that the down time without water to the building is minimized and/or planned for.
Booster Station Manufacturers:
Replacing Old 100HP VTP
w/New 50HP Pump & VFD
Replacing (2) Horizontal Pumps
w/50% Smaller Motors & VFDs
Complete Replacement Skid
(3) 10HP w/VFDs vs (2) 40HP & (1) 30HP