Why conventional control valves are the root of the problem:If the action of a control valve supplying water to an individual loop had no effect on the other loops, the loops would not cycle and excessive water would not be supplied to the closest loops to the pump and starved to the loops furthest from the pump. This more steady state operation will cause the delta Ts across the coils to rise and the flow rates to fall to achieve increased energy savings. This action can be achieved one hundred percent of the time with a control valve that will not change its delivery at each set point as the pressure drop across it changes. The term to describe the fixed flow rate with changing pressure drop is "pressure independence". |
