There are two identical power plants(i.e same turbine dimension and same generator configuration). Both have a hot reservoir. Coal is burnt on both power plant to make the temperature of the hot reservoir to be 300 degree Celsius. After setting the temperature no coal is being burnt.

One of the power plant is working on a Rankin cycle and other one on organic Rankin cycle.

With every repetition of the cycle the temperature of the hot reservoir is decreasing in both the power plant.

Will the power plant operating on organic Rankin cycle operate for longer duration since low heat is required for ORC cycle to take place?

I think that power plant with ORC cycle will generate more electricity.

I think that I am able to properly convey my query. Please guide me through my query.

  • $\begingroup$ Have you worked out the Carnot efficiency for both scenarios? Well explained to you here : engineering.stackexchange.com/a/40027/10902 $\endgroup$
    – Solar Mike
    Feb 8, 2021 at 18:13
  • 1
    $\begingroup$ Is your question basically "are organic-cycle power plants more efficient"? $\endgroup$
    – Wasabi
    Feb 8, 2021 at 20:19
  • $\begingroup$ You did the math why the ORC plant should generate more elctricity? Then write it down. Makes it easier for us to understand your thinking. $\endgroup$
    – mart
    Feb 9, 2021 at 7:23

1 Answer 1


There is no "this plant is more efficient than that plant" standard that can be met. The efficiency of each will be determined by the temperature range they are designed for. Organic Rankine cycle efficiency will be specifically related to the temperatures for the phase change. The low temp ability for the organic process is because you can specify the phase change temperatures.


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