Would it be possible to put a pump into a well-insulated loop with a needle valve and pressure transmitters on intake and exhaust side of pump and then just backcalculate the W the pump is putting into the water as a function of system resistance?
With my testbed it seems that pumps dump MORE heat into the loop when I throttle them during testing; pretty sure Bill sees this as well (I recall something about having to lower the set point on his chiller at low flow rates). Doesn't that sort of contradict the idea that they are pulling less power from the wall when there is more restriction? Or is the total power less but much more of it is being lost to friction?
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