Heat exchanger - efficiency of the cycle

In summary, the conversation discusses the possibility of the temperature at point 3 in a power cycle being above the critical temperature of 374°C and the implications for the efficiency of the cycle. The speaker also asks to see a TS diagram of the cycle to better understand the process. The conversation ends with the clarification that this is not a homework problem, but rather a point of curiosity.
  • #1
EastWindBreaks
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Homework Statement


T-s-Diagram-of-Vapour-Power-Cycle.png

Homework Equations

The Attempt at a Solution


Since we want the fluid to be in liquid state before entering a boiler, and super-heated water can only reach 374°C before entering super-critical state, suppose after the expansion, the temperature at point 3 is still higher than 374°C, does that mean the condenser must still reject enough heat to ensure the working fluid is in liquid form, since Q_out is large, the efficiency of the cycle won't be as good?
 

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  • #2
Let's see what your concept of the process looks like if the temperature at point 3 is above the critical temperature. Please show us the TS diagram, also showing, for reference, the vapor-liquid equilibrium region.

Is this really a homework problem?
 
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  • #3
Chestermiller said:
Let's see what your concept of the process looks like if the temperature at point 3 is above the critical temperature. Please show us the TS diagram, also showing, for reference, the vapor-liquid equilibrium region.

Is this really a homework problem?

its not a homework problem, I was just curious while reading about the textbook chapter on power cycles, since it is desirable to have high temperature input, I was thinking maybe that temperature can be so high that the temperature of the fluid coming out of the turbine might able to reach above 374 Celsius ?
 
  • #4
EastWindBreaks said:
its not a homework problem, I was just curious while reading about the textbook chapter on power cycles, since it is desirable to have high temperature input, I was thinking maybe that temperature can be so high that the temperature of the fluid coming out of the turbine might able to reach above 374 Celsius ?
OK. So let's see your TS diagram of the cycle. I'm particularly interested in the part of the path through the condenser (or cold sink).
 

1. How is the efficiency of a heat exchanger cycle calculated?

The efficiency of a heat exchanger cycle is calculated by dividing the actual heat transfer rate by the maximum possible heat transfer rate. This is expressed as a percentage and can range from 0-100%.

2. What factors affect the efficiency of a heat exchanger cycle?

The efficiency of a heat exchanger cycle is affected by factors such as the design and size of the heat exchanger, the temperature difference between the hot and cold fluids, the type of fluids being used, and the flow rate of the fluids.

3. How can the efficiency of a heat exchanger cycle be improved?

The efficiency of a heat exchanger cycle can be improved by increasing the surface area of the heat exchanger, using materials with high thermal conductivity, reducing the temperature difference between the fluids, and optimizing the flow rate of the fluids.

4. What is the role of the heat exchanger in a thermal power plant?

The heat exchanger in a thermal power plant is responsible for transferring heat from the steam produced by the boiler to the water in the condenser, thus increasing the efficiency of the power plant and reducing energy losses.

5. How does fouling affect the efficiency of a heat exchanger cycle?

Fouling, which is the accumulation of deposits on the surface of the heat exchanger, can significantly reduce the efficiency of a heat exchanger cycle. It can decrease the heat transfer rate and increase the pressure drop, leading to higher energy consumption and decreased performance.

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