charlie tuna
Senior Member
- Location
- Florida
the results of a recent survey suprised me concerning the installation of vsd's to maintain system pressure on a domestic water system. it might be something other contractors may want to inform their customers about. we have converted some smaller buildings in the past and gathered data information on power consumption savings.
we just completed monitoring a larger building of 55 stories and the payback period is less than fouteen months. the present setup is 1-25hp and 2-50hp supplying the upper floors and 2-30hp supplying the lower floors. with data loggers we projected the total power to be over a half million kilowatt hours of consumption per year. drive manufacturers say the savings are 2/3.. our experiance is about 45 per cent. the drive installation cost would be returned in less than fourteen months. the system pressure would be maintained by pump speed. the smaller buildings have ressulted in pumps running about 52 cycles and increase to 55 or 56 cycles during water demand. at 52 cycles the horsepower consummed by the motor was near 50 per cent. during this study on the 55 story building their power rates increased from .068 to .076 cents per kilowatt hour due to fuel surcharges -- this alone reflected an additional cost of nearly $5,000. per year to operate the domestic water system. this may allow some contractors an idea or two!!!
we just completed monitoring a larger building of 55 stories and the payback period is less than fouteen months. the present setup is 1-25hp and 2-50hp supplying the upper floors and 2-30hp supplying the lower floors. with data loggers we projected the total power to be over a half million kilowatt hours of consumption per year. drive manufacturers say the savings are 2/3.. our experiance is about 45 per cent. the drive installation cost would be returned in less than fourteen months. the system pressure would be maintained by pump speed. the smaller buildings have ressulted in pumps running about 52 cycles and increase to 55 or 56 cycles during water demand. at 52 cycles the horsepower consummed by the motor was near 50 per cent. during this study on the 55 story building their power rates increased from .068 to .076 cents per kilowatt hour due to fuel surcharges -- this alone reflected an additional cost of nearly $5,000. per year to operate the domestic water system. this may allow some contractors an idea or two!!!