ME elective: Energy Systems

Proof required

Link the public repo with 2.60J homework 1 written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Exergy balances name every destruction term.
• Dead-state conditions are stated.
• Answers match the published solutions, and misses are reworked.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of 2.60J homework 1, with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 14: Energy Systems, unit 1: Availability, exergy and energy conversion
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Exergy balances name every destruction term.
• Dead-state conditions are stated.
• Answers match the published solutions, and misses are reworked.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with 2.60J homework 2, 4 and 5 (where a problem asks for EES, a paid program, use Python with CoolProp) written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Combustion answers balance the reaction and state the air–fuel ratio.
• Cycle efficiencies are checked against an energy and an exergy balance.
• Answers match the published solutions, and misses are reworked.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of 2.60J homework 2, 4 and 5 (where a problem asks for EES, a paid program, use Python with CoolProp), with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 14: Energy Systems, unit 2: Combustion, gas turbines and combined cycles
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Combustion answers balance the reaction and state the air–fuel ratio.
• Cycle efficiencies are checked against an energy and an exergy balance.
• Answers match the published solutions, and misses are reworked.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with 2.60J homework 3 and problem 1 of homework 1 (compressed-air storage) written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Efficiencies are compared on the same basis (first or second law), stated.
• Storage answers give energy and power with units.
• Answers match the published solutions, and misses are reworked.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of 2.60J homework 3 and problem 1 of homework 1 (compressed-air storage), with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 14: Energy Systems, unit 3: Solar, fuel cells and storage
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Efficiencies are compared on the same basis (first or second law), stated.
• Storage answers give energy and power with units.
• Answers match the published solutions, and misses are reworked.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with the code or model files, the one command that reruns it, the convergence (mesh or step-size) study and the hand-calculation check, and a README that says how to rerun it and what limits the result.

What gets checked

• The code reproduces 2.60J homework 4 problem 3 within 1%, and one more point is checked by hand.
• The pressure-ratio sweep and the exergy breakdown are plotted with units and stated assumptions.
• The write-up explains where the largest exergy loss is and why.

Common mistakes

• A result that nobody else can rerun from the repo.
• A table with no explanation of the gaps.

Powstik Guide

A notebook that models a gas turbine with a steam bottoming cycle, using CoolProp for the steam side, in a public repo.

Steps

1. Write down what you expect before you start.
2. Model the Brayton topping cycle (air as an ideal gas) and the Rankine bottoming cycle, linked by a heat-recovery boiler. State every assumption: compressor and turbine efficiencies, turbine inlet temperature, a pinch point of about 10 K, the stack temperature and the dead state (25 °C, 1 atm). Treat the combustor as heat added, with fuel exergy about 1.04 times the lower heating value for natural gas. Check the code first against 2.60J homework 4 problem 3 and its solution. Sweep the gas-turbine pressure ratio and plot overall efficiency. Then draw an exergy-destruction breakdown by component.
3. Fill the predicted-vs-measured (or hand-vs-simulated) table.
4. Explain every gap with a cause someone can check.
5. Write the README and ask someone who knows the subject to check it.

README
ME 14: Energy Systems — Model a combined-cycle power plant
What I expected:
How to rerun it:
Predicted vs measured:
Why they differ:
Safety: hand tools and eye protection only

What gets sent back

• No convergence study, or no hand calculation that checks it.
• Machine tools, welding, pressure vessels, combustion, or springs and flywheels storing dangerous energy without a trained supervisor.

Resources

What a verifier looks for

• The code reproduces 2.60J homework 4 problem 3 within 1%, and one more point is checked by hand.
• The pressure-ratio sweep and the exergy breakdown are plotted with units and stated assumptions.
• The write-up explains where the largest exergy loss is and why.
• Check the engineering and the numbers, not just that it exists: do the units, the hand calculation and the table agree?
• Build photos show hand tools only and eye protection worn: no machine tools, welding, pressure vessels, combustion, or springs and flywheels storing dangerous energy (unless a trained supervisor and a proper workshop are shown).

You'll sign in first, then come straight back here.