Efficiency of Rankine Cycle Using R141b - Confirmation Needed

In summary, the conversation discusses the results of a lab session on the Rankine Cycle using R141b as the working fluid. The obtained efficiencies for the theoretical, practical, and isentropic processes were 13.01%, 12.07%, and 5.90% respectively. These values were compared to the efficiency of a Carnot Cycle, which was found to be 79.34%. The lower efficiency of the Rankine Cycle is due to its use of irreversible processes and as an open system. Additional information about the Rankine Cycle and its efficiencies can be found on websites such as Engineering Toolbox and Wikipedia.
  • #1
Juggler123
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I've just completed a lab session on the Rankine Cycle using R141b as the working fluid and have obtained some values for the different effciencies in the cycle. I have that;

ηTheoretical =13.01%
ηPractical =12.07%
ηIsentropic =5.90%

I'm pretty sure I've followed the lab sheet correctly but I'm not 100% sure these answers are correct since they seem very low, I've also calculated that the thermal efficiency of a Carnot Cycle based on the maximum and minimum temperatures is 79.34% which is an awful lot higher!

I thought I'd be able to find some typical values for this type of experiment (or similar) online but I'm having real trouble finding any material to refrence my answers against. Could anyone help me please? Are these answers anywhere near correct and where can I find material online as a refrence point for these answers?
Thanks!
 
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  • #2
Yes, your answers are correct. The Rankine Cycle is not as efficient as the Carnot Cycle because it does not use reversible processes. The Rankine Cycle is an open system, meaning some of the heat used to generate power is lost to the environment, whereas a Carnot Cycle is a closed system, meaning all of the heat used to generate power is used efficiently. Therefore, the Rankine Cycle will always have a lower efficiency than a Carnot Cycle. You can find more information about the Rankine Cycle and its efficiencies on websites such as Engineering Toolbox and Wikipedia.
 

Related to Efficiency of Rankine Cycle Using R141b - Confirmation Needed

1. What is the Rankine cycle and how does it work?

The Rankine cycle is a thermodynamic cycle used in power plants to generate electricity. It works by using a fluid, usually water, to absorb heat from a source and convert it into mechanical work. The fluid is then cooled and recycled back to the beginning of the cycle to repeat the process.

2. Why is R141b used in the Rankine cycle?

R141b is a type of refrigerant that is commonly used in power plants because of its high efficiency and low environmental impact. It has a low boiling point and can easily be converted into a gas, making it ideal for use in the Rankine cycle.

3. What are the benefits of using R141b in the Rankine cycle?

R141b has a high thermal efficiency, meaning it can convert a large amount of heat into mechanical work. It also has a low environmental impact, as it does not contribute to ozone depletion or global warming like some other refrigerants.

4. How is the efficiency of the Rankine cycle using R141b measured?

The efficiency of the Rankine cycle using R141b is typically measured by the thermal efficiency, which is the ratio of the net work output to the heat input. This can be calculated by dividing the work output by the heat input and multiplying by 100%.

5. Is there any confirmation needed for the efficiency of the Rankine cycle using R141b?

Yes, confirmation is needed through experimental testing and data analysis to accurately determine the efficiency of the Rankine cycle using R141b. This involves conducting experiments and collecting data on the performance of the cycle, which can then be compared to theoretical calculations to confirm the efficiency.

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