Can a Thermosyphon Rankine Power Plant Produce 0.1-0.25 kW of Power?

[dmalwcc89]

Homework Statement

I am supposed to see if there is a feasibility of producing power in the 0.1-0.25 kW range. I am working with a thermosyphon Rankine power plant. It is an open ended design problem

My question is that I am getting hung up on finding the mass flow rate. My professor says to treat it as an ideal Rankine cycle, but there is no work input at the pump stage (virtual pump). I have calculated the systems at each spot, so I have all enthalpy values, all temp and pressure values and all entropy values at each station.

Homework Equations

Qin/m = h1-h4
Qout/m = h2-h3
Wp/m = h4-h3
Wt/m = h1-h2
Wcycle = m[(h1-h2)-(h4-h3)] = m[Wt/m-Wp/m]

The Attempt at a Solution

I have calculated Qin/m, and Qout/m. But I am confused as how to calculate Wcycle (net power). Because m is in the way, I cannot compare the value I get of Wcyc/m. So my question is, is m a value I need to compose on my own since it is open ended, or is there a way I am forgetting to calculate it? If I do need to make my own value, how do I come up with that value?

 

[Redbelly98]

You're correct in that you can only calculate Wcycle/m. If you have twice as much of the substance, the engine will do twice as much work.

So: what does m/t need to be, in order to generate 0.1 to 0.25 kW?

 

[Mene]

my response would be to first clarify the question and make sure I understand the problem correctly. It seems like you are trying to determine the feasibility of producing power in the 0.1-0.25 kW range using a thermosyphon Rankine power plant. The focus of your question is on finding the mass flow rate and calculating the net power (Wcycle).

In order to calculate the mass flow rate, you will need to consider the specific properties of the fluid being used in the Rankine cycle and the specific design of the system. This may involve considering factors such as the heat transfer coefficient and the efficiency of the pump. It may also be helpful to consult with your professor or refer to your course materials for guidance on how to approach this calculation.

As for calculating the net power (Wcycle), you are correct in recognizing that the mass flow rate (m) is a necessary component. This value can be determined by considering the overall energy balance of the system, taking into account the heat input (Qin) and the work output (Wcycle). Again, consulting with your professor or referring to your course materials may provide helpful guidance on how to approach this calculation.

In summary, it is important to carefully consider the specific design and properties of the system in order to accurately calculate the mass flow rate and net power. Consulting with your professor or referring to your course materials may provide helpful guidance in this process.