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  1. billjg

    Efficient Motor Modulation

    I am a ChemE and am working on energy efficiency in pumping. 90% of the pumps out there are centrifugal with 60-70% best efficiency at one point on the pressure-flow curve. The design size is always larger than the operating size, so they actually operate at 50-60% efficiency or so. Worse, we...
  2. billjg

    Refrigeration Savings in Cold Weather

    Thank you for all of your responses. NickE, they probably use a heat pipe which is a tube closed at both ends partially filled with freon. One end is exposed to heat and the other exposed to cold. The cold end must be physically higher. Freon evaporates from the hot end, absorbing heat, and...
  3. billjg

    Refrigeration Savings in Cold Weather

    Is there any way to configure a chiller system to get free refrigeration in the winter? I need to cool water from 50F to 40F. In theory, in cold weather (<30F) I can; A. run the water through an air-cooled exchanger or B. pipe an evaporative chiller to a condenser coil exposed to cold air...
  4. billjg

    Materials of Construction for High Purity Water

    It is an open cooling tower. We will probably make provisions for occasional addition of potable water to keep the hardness up, monitor conductivity and monitor corrosion with a coupon rack. Thank you for your help! Bill
  5. billjg

    Materials of Construction for High Purity Water

    Thank you, bimr. This application is for a cooling tower for the purpose of clean operation and no purge. I have heard about the corrosivity of "demin" water on metals but never understood the mechanism. First of all, what consitutes "demin" water? 1 mmho/cm? 0.1? 0.01? I have heard that...
  6. billjg

    Materials of Construction for High Purity Water

    What should piping materials of construction be for RO, DI and distilled water? Roughly at what point (or points), in terms of TDS/mmhos, does the corrosivity of high purity water become a problem? Thanks, Bill

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