Heat Efficiency of a Carnot Engine

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SUMMARY

The discussion focuses on the efficiency of a Carnot engine operating between two temperature reservoirs, T1 and T2. It is established that doubling the temperature of the warmer reservoir (T1) increases the engine's efficiency by a factor of 5. The efficiency equation ε=1-(T2/T1) is utilized to derive the relationship between the temperatures and efficiency. The challenge lies in solving for the efficiency numerically and determining the temperature ratio T1/T2, which can be accomplished using two equations with two unknowns.

PREREQUISITES
  • Understanding of thermodynamics, specifically Carnot engines
  • Familiarity with efficiency equations in thermodynamic systems
  • Basic algebra for solving equations with multiple variables
  • Knowledge of temperature scales and their implications in thermodynamic calculations
NEXT STEPS
  • Calculate the efficiency of a Carnot engine using different temperature values
  • Explore the implications of temperature ratios on engine performance
  • Investigate real-world applications of Carnot efficiency in engineering
  • Learn about other thermodynamic cycles and their efficiencies
USEFUL FOR

Students studying thermodynamics, engineers designing thermal systems, and anyone interested in the principles of heat efficiency in engines.

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Homework Statement


A Carnot engine operates between a warmer reservoir at a temperature T1 and a cooler reservoir at a temperature T2. It is found that increasing the temperature of the warmer reservoir by a factor of 2.00 while keeping the same temperature for the cooler reservoir increases the efficiency of the Carnot engine by a factor of 5.00. Find the efficiency of the engine and the ratio of the temperatures of the two reservoirs in their original form.


Homework Equations


ε=1-(T2/T1)


The Attempt at a Solution



I think we are supposed to get a numerical value for an answer but I don't think I have enough information.

So I start with

ε=1-(T2/T1)

The question states, "increasing the temperature of the warmer reservoir by a factor of 2.00 while keeping the same temperature for the cooler reservoir increases the efficiency of the Carnot engine by a factor of 5.00"

That means T1 will be doubled and once that happens, ε is quintupled, resulting in...

5ε=1-(T2/2T1)

The question asks for the efficiency, which I am supposed to answer with a numerical value. So I tried solving for ε.

ε=(1/5)-(T2/10T1))

I can't think of a way to solve this with 2 independent variables. Am I ignoring something from the question that would point me towards a value? Maybe I'm forgetting some mathematical property?

Once I have the efficiency then I can solve for the ratio of the two temperatures. Since it asks me for the ratio, I assume that knowing T1 and T2 are not required, so how could we solve for ε and get a numerical value?

Thanks in advance
 
Physics news on Phys.org
Use R for ##T_1/T_2##. Now you have 2 equations in 2 unknowns!
 
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Likes   Reactions: 1 person
BvU said:
Use R for ##T_1/T_2##. Now you have 2 equations in 2 unknowns!

Thanks! I knew it was staring at me in the face.
 

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