Heat from an infinite reservoir?

In summary: An infinite capacity in this context means that the reservoir can hold an unlimited amount of heat.A nuclear power plant.Yes, evaporation and condensation of the precipitation cycle is a simpler model for the formula.In summary, a refrigerator needs to pump heat from a low temperature reservoir to a high temperature reservoir. The low temperature reservoir has infinite heat capacity, the high temperature reservoir does not.
  • #1
Dawei
30
0
Hello,

For a refrigerator, if a low temperature (TL) reservoir has infinite heat capacity, what is the heat QL that is coming from it?

I have W = Qh - QL and I believe I know what Qh is, but I need a better way to express QL, something involving TL, TH, and/or W.

I know QL = CpdT, but obviously that does not help in this case...
 
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  • #2
Can you please elaborate on your question more?
 
  • #3
Hm, I guess it wasn't quite straightforward. It's just a simple refrigerator, pumping heat from a low temperature reservoir to a high temperature reservoir by inputting work W.

The low temperature reservoir has infinite heat capacity, the high temperature reservoir does not.

I'm trying to find an equation for the heat flowing from the low temperature reservoir.
 
  • #4
Both reservoirs are assumed to have infinite heat capacity. That's the only way to achieve a steady-state with a constant temperature for each.

...so I'm not clear on what the issue is here either.
 
  • #5
russ_watters said:
Both reservoirs are assumed to have infinite heat capacity. That's the only way to achieve a steady-state with a constant temperature for each.

The other reservoir, the hot one, does not have infinite heat capacity, it is maintaining a constant temperature because it is losing heat at the same rate that it is coming in from the refrigerator.
 
  • #6
Dawei said:
The other reservoir, the hot one, does not have infinite heat capacity, it is maintaining a constant temperature because it is losing heat at the same rate that it is coming in from the refrigerator.
In that case, it's an open system - and the cold reservoir would work the same way.
 
  • #7
Dawei said:
I'm trying to find an equation for the heat flowing from the low temperature reservoir.

Let H represent the hot temperature energy and L represent the low temperature energy.

H=L
 
  • #8
What is the 'infinite capacity', a nuclear power plant?
Is the evaporation and condensation of the precipitation cycle not a simpler model for the formula?
The Earth supplies the infinite heat, the atmosphere the infinite cooling and it rains all the time.
[However none of the above is truly 'infinite'.]
 

1. What is an infinite reservoir?

An infinite reservoir is a theoretical concept used in thermodynamics to represent a source or sink of heat that has an infinite capacity to supply or absorb heat without changing its temperature. It is often used as a simplification in calculations and models.

2. How is heat transferred from an infinite reservoir?

Heat is transferred from an infinite reservoir through a process called heat transfer, which can occur through three mechanisms: conduction, convection, and radiation. Conduction is the transfer of heat through a solid material, convection is the transfer of heat through a fluid, and radiation is the transfer of heat through electromagnetic waves.

3. What is the significance of an infinite reservoir in thermodynamics?

An infinite reservoir is significant in thermodynamics because it is a boundary condition that allows for the analysis and understanding of heat transfer processes in a simplified way. It allows scientists to make assumptions and approximations that make calculations and models more manageable.

4. Can an infinite reservoir actually exist in real life?

No, an infinite reservoir cannot exist in real life. It is a theoretical concept used in thermodynamics to simplify calculations and models. In reality, all sources and sinks of heat have finite capacities and will eventually reach equilibrium with their surroundings.

5. How does an infinite reservoir affect the efficiency of a heat engine?

An infinite reservoir does not affect the efficiency of a heat engine. In fact, the efficiency of a heat engine is determined by the temperatures of the hot and cold reservoirs and is independent of their size or capacity. This is known as the Carnot efficiency and is the theoretical maximum efficiency that a heat engine can achieve.

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