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The Carnot Icemaker

  • #1
An ice-making machine inside a refrigerator operates in a Carnot cycle. It takes heat from liquid water at 0.0 C and rejects heat to a room at a temperature of 22.2 C. Suppose that liquid water with a mass of 86.2 kg at 0.0 C is converted to ice at the same temperature. Take the heat of fusion for water to be L_f = 3.34×10^5 J/kg.

How much heat |Q_H| is rejected to the room?

Q_H = -W = nRT_H(lnV2/V1)

(V2/V1)^gamma-1 = T1/T2 = Tc/Th
 

Answers and Replies

  • #2
Chi Meson
Science Advisor
Homework Helper
1,789
10
Q_H = -W
this part is not correct. The ejected heat into the room is more than the work done.
(V2/V1)^gamma-1 = T1/T2 = Tc/Th
This is not a required formula. Consider the Carnot efficiency formula
 
  • #3
i figured out the Qh and got 3.113x10^7 J but now it wants to know how much Energy E must be supplied to the engine, in joules. I know that E_int= Q+W but says im wrong... any help?
 
  • #4
alphysicist
Homework Helper
2,238
1
Hi horsegirlf09,

There are three energy transfers to keep track of: Qc, which is the heat removed from the cold reservoir or system; Qh, which is the heat expelled into the hot reservoir; and W, which is the work done by the engine. How are these three related?
 
  • #5
An ice-making machine inside a refrigerator operates in a Carnot cycle. It takes heat from liquid water at 0.0 degrees Celsius and rejects heat to a room at a temperature of 26.0 degrees Celsius. Suppose that the liquid water with a mass of 70.0 kg at 0.0 degrees Celsius is converted to ice at the same temperature. Take the heat of fusion for water to be L_f = 3.34x10^5 J/kg. How much heat |Q_H| is rejected to the room? Express your answer in joules to four significant figures.

I get this information to some site that i get research in google search....



____________________
Scotsman Ice Machine
 

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