Engineering thermodynamics: choose a book and build an energy balance
Start by learning to draw a boundary and account for energy. A correct-looking equation is useful only when its system, property model and signs are clear. This guide helps you choose one main text and test what you can actually do with it.
Course topic: Engineering Thermodynamics
Study route and exercise: University Reading List editorial project. How we curate · Sources checked:
Scope and responsibility
A site-authored guide for a first undergraduate engineering thermodynamics course. The route and exercises below are editorial recommendations, not a university assignment or a claim of teaching experience. Chapter references mean Çengel 10th International Student Edition, Moran 9th edition and Yan’s 2022 open text; they are not interchangeable across editions. Progress by the checkpoints rather than a fixed weekly timetable.
Choose your starting point
I need a free starting point
Use Yan for boundaries, properties and the two laws. If your syllabus reaches detailed power or refrigeration cycles, arrange library access to the assigned full text before that stage.
My course assigns Çengel
Match the assigned edition and homework first. Use Yan to repair a concept, then return to the course problems; another commercial textbook need not be your first purchase.
I can choose my main textbook
Consider Moran if you want to organise solutions around a written model and systematic checks. Choose it as an alternative main text, rather than reading two full texts in parallel.
Compare the three books
Introduction to Engineering Thermodynamics
Claire Yu Yan · 2022
Free foundation and concept repair
- Choose it when
- You want legal full-text access and short sections with interactive practice.
- Use another route when
- Your immediate assignment needs detailed Rankine, Brayton or vapour-compression cycle calculations beyond this introduction.
- Selected reading
- Read chapters 1–3 for systems and properties, 4–5 for energy balances, then 6 for entropy and second-law limits.
- Limits and trade-offs
- Six chapters keep the entry route manageable. Carnot and refrigerator concepts are included, but dedicated chapters on detailed engineering cycles are absent.
Try before choosing
After Yan 4.4, draw a boundary around a sealed rigid vessel and a negligible-storage heater. Label 6 kJ electrical input and 1 kJ heat loss; write the energy balance before calculating.
Check your work: Your ledger gives ΔU=5 kJ. Zero moving-wall work does not remove electrical work; give the sign convention and identify which objects store energy.
Thermodynamics: An Engineering Approach
Yunus A. Cengel; Michael A. Boles; Mehmet Kanoglu · Edition: 10 (International Student Edition, Print) · 2024
Broad course text with engineering applications
- Choose it when
- Your lecturer assigns the tenth edition, or your course extends from basic balances to several engineering cycles.
- Use another route when
- You only need a free introductory route or have already selected another full course text.
- Selected reading
- First pass: chapters 1–5, then 6–8. Choose chapter 10, 11 or 12 for your first cycle project; defer the other specialist topics.
- Limits and trade-offs
- The breadth supports later study but makes a cover-to-cover first pass inefficient. This edition separates entropy and entropy analysis into chapters 7 and 8; check older problem references.
Try before choosing
For one cycle chapter listed above in Çengel, sketch its components and state points. For each state, list the two properties you would need to establish before using a table; do not guess numerical values.
Check your work: The state list distinguishes saturated and single-phase cases and identifies the needed table or relation. If property selection, not the cycle diagram, blocks you, revisit the properties chapter first.
Fundamentals of Engineering Thermodynamics
Michael J. Moran; Howard N. Shapiro; Daisie D. Boettner; Margaret B. Bailey · Edition: 9 · 2018
Systematic alternative main text
- Choose it when
- You benefit from making the physical model, assumptions and solution checks explicit on paper.
- Use another route when
- You must submit problems from another assigned text and cannot readily reconcile its numbering and property data.
- Selected reading
- Use chapters 1–4 for fundamentals, 5–6 for the second law and entropy, then 8, 9 or 10 for a selected cycle.
- Limits and trade-offs
- Its problem-solving structure is useful, but the order differs: closed-system energy precedes the main property chapter. The publisher’s contents PDF is a sample, not the complete free book.
Try before choosing
Use Moran’s fundamentals route to turn the same vessel scenario into a model sheet: system, assumptions, transfer arrows, governing equation and final check.
Check your work: A second reader can recover the 5 kJ change from your stated signs. Each neglected storage or transfer term has an explicit reason, rather than being silently deleted.
Check your preparation
A heater draws 2 kW for 90 s. How much energy is supplied?
180 kJ, because 1 kW = 1 kJ/s. A balance over a process uses energy; a steady-device balance commonly uses a rate. Do not combine kJ and kW in the same sum.
Does a sealed rigid tank have zero heat transfer and zero work?
No. Sealed excludes mass transfer, rigid excludes volume-change boundary work, and adiabatic excludes heat transfer. Electrical work can still enter a sealed rigid tank.
Can Celsius temperatures be used in every thermodynamic ratio?
No. A 20 °C temperature change equals 20 K, but temperature ratios in Carnot limits require absolute temperatures. For example, 300 K / 600 K = 0.5; subtracting 273.15 before taking that ratio changes its meaning.
Six steps with a concrete output
Outputs marked ready: 0 / 6
These are your own study marks, not an assessment. They are not sent to this site.
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1. Draw the system before choosing an equation
Selected reading: Çengel 10: chapters 1–2; Moran 9: chapters 1–2; Yan: chapter 1.
Make this: Sketch a sealed tank and a steady turbine. Label mass, heat and work arrows; convert 2 kW over 90 s into energy.
Check your work: Explain which transfers each boundary permits and recover 180 kJ without confusing power with energy.
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2. Make a property ledger
Selected reading: Çengel 10: chapter 3; Moran 9: chapter 3; Yan: chapters 2–3.
Make this: Using states from your chosen book, list phase, two independent properties, the table or model used, and units for u, h and v for three states.
Check your work: Explain why saturation temperature and pressure alone cannot determine the quality of a two-phase mixture. Justify an ideal-gas assumption before using it.
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3. Close an energy balance
Selected reading: Çengel 10: chapter 4; Moran 9: chapter 2; Yan: chapter 4.
Make this: Solve the original tank example below, then identify the additional boundary-work term if the wall were replaced by a moving piston.
Check your work: Recover 80 kJ of stored energy and 355.7 K. Explain why a rigid wall removes expansion work but does not remove electrical input.
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4. Follow energy through a steady device
Selected reading: Çengel 10: chapter 5; Moran 9: chapter 4; Yan: chapter 5.
Make this: For an adiabatic steady turbine, take mass flow 1.5 kg/s, inlet enthalpy 3200 kJ/kg and outlet enthalpy 2600 kJ/kg. Neglect kinetic and potential energy changes; find shaft power.
Check your work: Obtain 900 kW output. State the assumptions and explain why enthalpy already includes flow work, so an extra pv term would double count it.
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5. Test feasibility with the second law
Selected reading: Çengel 10: chapters 6–8; Moran 9: chapters 5–6; Yan: chapter 6.
Make this: Test an engine claiming 60% efficiency while exchanging heat only with reservoirs at 600 K and 300 K. Write a reason for accepting or rejecting it.
Check your work: Reject the claim: the reversible upper bound is 1 − 300/600 = 50%. Energy conservation alone does not establish feasibility.
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6. Build one complete cycle account
Selected reading: Çengel 10: choose chapter 10, 11 or 12; Moran 9: choose chapter 8, 9 or 10. Yan supplies the foundations; use a full text for a detailed engineering cycle.
Make this: Choose one power or refrigeration cycle from that text. Produce a state table, component balances and efficiency or COP; change one operating parameter using the same property source.
Check your work: Define the denominator of efficiency or COP, check energy closure and second-law restrictions, and explain which idealisations limit the result. Finish one cycle before adding another.
Worked exercise
Original example: electrical heating in a sealed rigid tank
A rigid tank contains 2.00 kg of air initially at 300 K. An internal electrical heater receives 100 kJ through its wires while 20 kJ of heat escapes to the room. Find the final uniform air temperature.
Assumptions
The system is the air plus a heater with negligible energy storage. No mass crosses the boundary. Tank-wall energy storage and kinetic and potential energy changes are neglected. Model air as an ideal gas with constant cv = 0.718 kJ/(kg·K), supplied for this exercise. Heat into the system is positive; work out is positive.
- The wall does not move, so volume-change boundary work is zero. Electrical work still crosses the boundary: W = −100 kJ. Heat leaves, so Q = −20 kJ.
- Apply the closed-system balance: ΔU = Q − W = −20 − (−100) = 80 kJ.
- For the stated constant-cv model, ΔU = m cv (T2 − T1). The heat capacity is 2.00 × 0.718 = 1.436 kJ/K.
- Therefore T2 − T1 = 80 kJ / (1.436 kJ/K) = 55.71 K, and T2 = 300 + 55.71 = 355.71 K.
Answer and interpretation
T2 ≈ 355.7 K (82.6 °C). The stored energy increases by 80 kJ, not by the full 100 kJ of electrical input.
Test the result
With no heat loss, the same model gives 369.6 K; 355.7 K is correctly between 300 K and that bound. At fixed mass and volume, p2/p1 = T2/T1 ≈ 1.186, so pressure rises. Redo the problem with 40 kJ heat loss: predict a lower temperature before calculating 341.8 K.
Change an assumption
When the tank wall also stores energy
Retain the original 2.00 kg air, 300 K initial temperature, 100 kJ electrical input and 20 kJ external loss. Change the boundary to air, negligible-storage heater and tank wall together. The wall starts at 300 K, has constant heat capacity 0.500 kJ/K, and reaches the same final temperature as the air. Keep the supplied constant cv=0.718 kJ/(kg·K) and all other original idealizations.
- The combined system still receives net 80 kJ; heat exchanged internally between wall and air does not cross its outer boundary.
- Its total heat capacity is 2.00×0.718+0.500=1.936 kJ/K. Therefore ΔT=80/1.936≈41.322 K and T2≈341.322 K.
- Air stores 1.436×41.322≈59.339 kJ and the wall 0.500×41.322≈20.661 kJ. These add to 80 kJ; treating all 80 kJ as air storage would answer the old model instead.
Answer and interpretation
The common final temperature is about 341.3 K. Wall storage lowers the predicted temperature relative to 355.7 K in the original negligible-wall-storage model, without changing the external energy ledger.
Test the result
Set the wall heat capacity to zero to recover the original result. With positive heat capacity and the same energy input, the temperature rise must decrease. This comparison tests a modeling assumption, not the safety or construction of an actual vessel.
Common mistakes
Equating rigid with zero work
Write the type of work beside each arrow. Zero volume change only removes the boundary-work term; electrical or shaft work needs its own accounting.
Choosing properties after doing the algebra
Identify the phase before selecting a table. Saturated mixtures need an additional property such as quality; ideal-gas formulae cannot replace every steam-table lookup.
Treating a balanced equation as a feasible device
A first-law balance can conserve energy for an impossible engine. Check the second law separately and use kelvin for absolute temperature ratios.
Before moving on
- Solve an unfamiliar closed-system and steady-flow problem with a labelled boundary, justified property model, consistent units and an independent check.
- Reproduce the tank solution without looking, then predict and explain the effect of changing heat loss before doing the arithmetic.
- Write a one-page cycle account naming its assumptions and the next topic you need. Revisit the stage whose checkpoint failed rather than buying another overlapping textbook.
Sources and edition checks
Sources checked:
- McGraw Hill — tenth International Student Edition and contents
The publisher confirms the selected tenth ISE, ISBN 9781266152115, and its chapter order. It lists ©2024 with release on 30 January 2023. Scope choices here are site editorial judgments, not an independent classroom evaluation.
- Wiley — ninth-edition frontmatter and contents
Wiley’s ninth-edition frontmatter and contents support the edition, problem-solving structure and chapter mapping. The linked PDF is a publisher sample; the guide does not claim that the whole commercial book is freely available.
- Claire Yu Yan / BCcampus — open textbook and publication details
The author’s BCcampus book page identifies the 2022 open text, full reading/download access and introductory undergraduate scope. Its noncommercial licence is distinct from permission to read it; this guide links to it and supplies an original exercise.
- Claire Yu Yan / BCcampus — complete table of contents
The author’s contents support the six-chapter route and the limits of its detailed cycle coverage. The six stages on this page are our study plan, not a published syllabus or assigned university sequence.
- Claire Yu Yan / BCcampus — section 4.4, closed-system first law
Section 4.4 supports the governing closed-system balance and stated sign convention. The tank data, calculation, follow-up check and teaching sequence here were created for this guide, not taken from its worked examples.
These are proposed study activities, not official course assignments or a claim that every book has been read cover to cover.