Last month, we discussed how a constant volume heating, ventilation and air conditioning (HVAC) system would continually pump the same flow rate of chilled water through the entire system regardless of the cooling load.
A recent question I received from an engineer in the Middle East had to do with a “double control” of boiler feed pumps (BFPs) at his power plant. The system was controlled both by set position of the valves as well as variable speed drives. I was intrigued.
Entrained air is typically measured by volume at atmospheric pressure and not by weight. While not a totally inclusive list, the following are the most common reasons for air entrainment in pump systems:
Though medium-voltage variable frequency drives (VFDs) are proven to improve operational efficiency and reduce costs, their electronic components can be negatively affected by the harsh environmental conditions in which large drives are commonly found.