Calculating work output of an engine, using ideal gas

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Homework Help Overview

The discussion revolves around calculating the work output of a Stirling engine operating with an ideal gas. The engine's parameters include the amount of gas, operating temperatures, and the volume change during expansion strokes.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to determine the work done by the engine per cycle by calculating energy input and output using the provided temperatures and amount of gas. Some participants question the clarity of the problem statement and whether the original poster's assumptions about needing to find energy values are correct. Others suggest that drawing a PV diagram may aid in understanding the cycle better.

Discussion Status

The discussion is ongoing, with participants exploring the problem's requirements and clarifying the original poster's understanding of the calculations involved. There is no explicit consensus yet, but suggestions for visual aids and further clarification are being made.

Contextual Notes

There is a noted lack of clarity in the original problem statement regarding what exactly needs to be calculated, which has led to some confusion among participants.

lagwagon555
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Homework Statement



A model Stirling engine uses n = 8.04 × 10–3 mol of gas (assumed to be ideal) as a working substance. It operates between a high temperature reservoir at TH = 98.0 °C and a low temperature reservoir at Tc = 25.0 °C. The volume of its working substance doubles during each expansion stroke. It runs at a rate of 0.7 cycles per second. Assume the engine is ideal.

How much work does the engine do per cycle?

Homework Equations



W(eng) = Qh - Qc

The Attempt at a Solution



I assume that you have to find the energy input and output by using the temperatures, and the mol of gas, taking into account it's an ideal gas. However, taking the first step is the problem. I have no clue how to work out Qh and Qc, from the given data. Or perhaps there's some other way you have to solve it?
 
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What does the problem actually ask you to calculate? You don't seem to have included that in the problem statement... does it actually say you need to find the energy input and output, or are you just guessing at that?
 
I can't believe I forgot to put that question in. I edited the original - sorry about that.
 
Have you drawn the PV diagram for an idealized Stirling cycle? If not, that would help with figuring out what's going on.
 

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