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heat added to fluid by pump

heat added to fluid by pump

heat added to fluid by pump

(OP)
How do I calculate the heat added by a pump (turbine, PD, centrifugal)to the coolant on my chiller?

RE: heat added to fluid by pump

It is approximately equal to the power delivered to the pump which is not converted to hydraulic energy.

The hydraulic power that must be converted into energy and delivered to the pumped product is,

P_hydraulic = 144 x flowrate x density x (output_pressure - inlet_pressure)

flowrate ft3/sec
density lbs/ft3
pressures psig
P_hydraulic ft-lbs/sec

The Pump's Efficiency determines how much power must be applied to the pump shaft so it can deliver the hydraulic power into the pumped product.  Since some energy is lost during that process, more energy must be applied than is actually converted to energy and used by increasing the fluid's pressure.  The pump's efficiency determines how much extra energy is needed.

The pump's Efficiency varies with flow through your pump and can be read from your pump curve.

Power_Required at shaft = P_Hydraulic / efficiency

Power not used is converted to heat, of which most goes into heating the fluid.  It is of course equal to P_Required - P_hydraulic.

The units of Power (ft-lbs/sec) not used can be converted to Btu/sec by dividing by 778 Btu/ft-lb

   Going the Big Inch! worm
http://virtualpipeline.spaces.msn.com

RE: heat added to fluid by pump


BigInch is right, other energy effects -e.g., noise and heat dissipated through the pump casing- are considered to be too small to worry about.

RE: heat added to fluid by pump

Doesn't one have to include elevation difference between pump outlet and inlet nozzles?

Regards

RE: heat added to fluid by pump

Sailo,

If its a design situation, probably not.

Otherwise, it depends on where you think are good places to obtain your "inlet" and "outlet" pressure data, but if it was an existing installation, I'd just install some temperature gauges and read it directly.

   Going the Big Inch! worm
http://virtualpipeline.spaces.msn.com

RE: heat added to fluid by pump

BigInch-Check with a vendor-TDH, etc is from inlet to outlet flange,

Regards

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