Quote:
Originally posted by myv65
The motor's inefficiency mainly goes off as convection for an inline pump. It obviously goes into the water for a submerged pump. The pump's inefficiency goes into thermal energy in the water. The pump's useful energy goes into circulating flow. All of the energy put into the pump's motor must eventually leave the box. Under steady-state conditions, energy leaving equals energy entering. For a while after starting up, energy leaving is less than entering with the excess showing up as thermal energy in the fluid (and kinetic energy of the moving fluid). After powering off, flow will slow to a halt and the fluid will cool to ambient. This is the release of stored energy and results in an energy output with no energy input.
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I see what you mean, but...
I think that what we're talking about here involves 2 things:
1-The efficient part of the pump (say 70%), which moves the water, which heats up due to friction.
2-The inefficient part of the pump (the remaining 30%), which includes (but not limited to) heat, which heats up the water through the pumps housing. This is reduced if the pump is in-line.