# Heat pump

## Homework Statement

A pump, operating at 10 W, is used to raise the pressure of a stream of water at 2.5 mol/s from 1 bar to 2 bar. At steady state, if the water temperature should remain constant at 25oC, how much heat exchange between the pump and its surroundings is required? Note that 1 bar = 105 Pa and C liq,water = 4.18 J g-1 K -1

PV=NRT

## The Attempt at a Solution

I tried to set up two equations. The first one is (1)(V)=NR(373+25) and the second is (2)(V)= NR(373+25)
and I dunno find out the heat exchange since there are some unknown data( Volume? Mole?)
[/B]

Chestermiller
Mentor

## Homework Statement

A pump, operating at 10 W, is used to raise the pressure of a stream of water at 2.5 mol/s from 1 bar to 2 bar. At steady state, if the water temperature should remain constant at 25oC, how much heat exchange between the pump and its surroundings is required? Note that 1 bar = 105 Pa and C liq,water = 4.18 J g-1 K -1

PV=NRT

## The Attempt at a Solution

I tried to set up two equations. The first one is (1)(V)=NR(373+25) and the second is (2)(V)= NR(373+25)
and I dunno find out the heat exchange since there are some unknown data( Volume? Mole?)[/B]
The solution to this problem has nothing to do with the ideal gas law. This is a problem in application of the open system (control volume) version of the first law of thermodynamics.

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