(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A coal-fired plant generates 600 MW of electric power. The plant uses

4:8106 kg of coal each day. The heat produced by the combustion of coal is 3:3107 J/kg.

The steam that drives the turbines is at a temperature of 300C, and the exhaust water is at

37C. (a) How much thermal energy is exhausted each day by this plant? (b) How much ice

at -10C can be turned into steam at 100C per year by the exhaust from this power plant?

2. Relevant equations

Q=mL

Q=mcΔT

3. The attempt at a solution

For question a) all I did was take the coal used each day and multiplied it by the heat produce by its combustion. I found the thermal energy exhausted each day to be 1.584 x 10^14J. (I think this is right)

Question B is where I am having troubles.

This is the equation I got:

Q=mCice(0-(-10))+mLice+mCwater(100-0)+mLvaporization

q/(Cice(10)+Lice+Cwater(100)+Lvice)=m

where:

Lice=334 J/g

Cice=2.1J/gK

Cwater=4.2 J/gk

Lvice=2.256J/g

Q=1.584 x 10^14

Is this right? I getting confused about what energy I should and shouldn't take when trying to find the mass.

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# Homework Help: Thermodynamics: Waste heat and total ice converted to steam

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