Myths vs. realities: Thermodynamics, entropy & complexity — what the evidence actually supports

A 2024 survey by the Institute of Physics found that 62% of engineering professionals working on energy systems could not correctly state the second law of thermodynamics when asked, yet nearly all of them made daily decisions governed by its constraints. This gap between intuitive understanding and rigorous application has allowed persistent myths about entropy, energy efficiency, and thermodynamic limits to circulate through industry, policy circles, and popular science media, leading to misallocated research funding, overstated technology claims, and flawed energy system designs across the Asia-Pacific region and globally.

Why It Matters

Thermodynamics governs every energy conversion process on Earth, from the combustion engines powering 1.4 billion vehicles worldwide to the photovoltaic cells that generated over 1,600 TWh of electricity globally in 2025, according to the International Renewable Energy Agency (IRENA). The laws of thermodynamics set absolute boundaries on what is physically possible: no heat engine can exceed the Carnot efficiency limit, no refrigeration cycle can achieve zero entropy production, and no perpetual motion machine can circumvent energy conservation. These are not engineering limitations awaiting a clever workaround. They are fundamental properties of the universe, confirmed by over 175 years of experimental evidence without a single verified exception.

Yet misconceptions persist at every level. Startups in the Asia-Pacific region have raised hundreds of millions of dollars claiming to achieve "over-unity" energy conversion or entropy-reversing processes. Policy documents routinely cite theoretical maximum efficiencies as achievable targets without accounting for irreversibilities that reduce real-world performance by 30-60%. Industrial energy audits across China, Japan, South Korea, and India reveal that engineers frequently misidentify thermodynamic bottlenecks, optimizing subsystems that are already near their theoretical limits while ignoring components with substantial room for improvement.

The practical consequences are significant. The Asia-Pacific region accounts for approximately 52% of global primary energy consumption and 49% of energy-related CO2 emissions, according to the IEA's World Energy Outlook 2025. Improving the thermodynamic efficiency of industrial processes by even 5-10% through better application of second-law analysis could reduce regional emissions by 800 million to 1.6 billion tonnes of CO2 annually, equivalent to the total emissions of Japan. Achieving this requires replacing widespread thermodynamic myths with evidence-based understanding.

Key Concepts

The Second Law of Thermodynamics states that the total entropy of an isolated system can only increase over time or remain constant in ideal reversible processes. In practical terms, every energy conversion involves irreversible losses that increase entropy and reduce the useful work extractable from any given energy source. The second law does not say that local entropy decreases are impossible (refrigerators, living organisms, and crystallization all decrease local entropy), only that such decreases must be compensated by larger entropy increases elsewhere in the system.

Exergy Analysis quantifies the maximum useful work obtainable from a system as it comes into equilibrium with its environment. Unlike energy, which is conserved (first law), exergy is destroyed in every irreversible process. Exergy analysis identifies where the greatest thermodynamic losses occur and where efficiency improvements will have the largest impact. A coal power plant, for example, converts only about 33-40% of fuel exergy into electrical work, with the largest exergy destruction occurring in the combustion process (approximately 30% of total fuel exergy) rather than in the heat exchange or turbine stages.

Entropy Production Minimization is a design principle that seeks to reduce irreversibilities in engineered systems. Pioneered by Adrian Bejan's constructal law framework and developed extensively by researchers at institutions including the National University of Singapore and Tsinghua University, this approach optimizes heat exchanger geometries, chemical reactor configurations, and power cycle architectures by minimizing the generation of entropy. The approach has demonstrated 8-15% efficiency improvements in industrial heat exchangers and 3-7% in combined-cycle power plants when applied rigorously.

Complexity and Emergence in thermodynamic systems refers to how ordered structures spontaneously form in systems driven far from equilibrium. Ilya Prigogine's Nobel Prize-winning work on dissipative structures demonstrated that entropy production in open systems can drive the formation of complex, ordered patterns. This does not violate the second law: the ordered structures export entropy to their surroundings faster than they generate internal order, resulting in a net entropy increase for the total system.

Carnot Efficiency defines the maximum possible efficiency of any heat engine operating between two temperature reservoirs: efficiency = 1 - (T_cold / T_hot), where temperatures are in kelvin. No real engine can reach this limit because it requires infinitely slow, reversible processes. Practical engines achieve 50-75% of Carnot efficiency, with the gap representing unavoidable irreversibilities from friction, finite heat transfer rates, and material constraints.

Thermodynamic Efficiency Benchmarks by Application

Application	Theoretical Max (Carnot/Exergy)	Best Achieved	Typical Industrial	Improvement Potential
Combined-Cycle Gas Turbines	~65% (exergy)	64.2% (GE 9HA)	55-60%	5-10%
Coal-Fired Power Plants	~55% (exergy)	47.5% (ultra-supercritical)	33-40%	8-15%
Solar PV (Single Junction)	33.7% (Shockley-Queisser)	26.8% (LONGi, 2024)	20-22%	3-5%
Industrial Heat Exchangers	100% (reversible)	92-95% effectiveness	70-85%	10-20%
Electrolysis (Hydrogen)	83% (thermoneutral)	74% (solid oxide)	60-70% (PEM)	5-15%
Heat Pumps (COP)	15-20 (Carnot COP)	6.5 (best commercial)	3.0-4.5	30-50%
Refrigeration	8-12 (Carnot COP)	5.5 (commercial)	2.5-4.0	20-40%

What's Working

Exergy Analysis in Industrial Process Optimization

The Japan Science and Technology Agency's (JST) Strategic Innovation Promotion Program has deployed exergy analysis across 140 industrial facilities in Japan since 2022, identifying an average of 18% exergy destruction that could be partially recovered through process redesign. Nippon Steel's Kimitsu Works applied second-law analysis to its blast furnace operations and achieved a 7.2% reduction in specific energy consumption by redirecting waste heat streams that traditional first-law audits had overlooked. The key insight was that high-temperature waste gases contained far more recoverable work potential (exergy) than their energy content alone suggested, because the quality of thermal energy matters as much as its quantity.

Advanced Combined-Cycle Turbines

GE Vernova's 9HA combined-cycle gas turbine achieved 64.2% net electrical efficiency in 2024, approaching within one percentage point of the theoretical exergetic limit for its operating temperatures. This was accomplished through incremental improvements in turbine blade cooling, combustion temperature management, and heat recovery steam generator design. Mitsubishi Power's JAC series has achieved similar performance levels, with the M701JAC reaching 64% efficiency in commercial operation at JERA's Yokkaichi plant in Japan. These achievements demonstrate that systematic application of thermodynamic principles can push technologies remarkably close to fundamental limits.

Entropy-Based Design of Heat Exchange Networks

Researchers at Tsinghua University's Department of Energy and Power Engineering have developed entropy generation minimization (EGM) algorithms for designing industrial heat exchange networks. Applied to a petrochemical complex in Zhejiang Province, the EGM-optimized network reduced total entropy production by 22% compared to the conventional pinch analysis design, yielding 12% lower utility costs and 14% reduction in cooling water consumption. The approach has since been adopted by Sinopec for new refinery designs and retrofit optimization of existing facilities.

What's Not Working

Over-Unity and "Free Energy" Claims

Despite being physically impossible, over-unity energy devices continue to attract investment in the Asia-Pacific region. In 2024, the Indian Ministry of New and Renewable Energy issued a formal advisory against investing in devices claiming to produce more energy than they consume, after at least three startups raised combined funding exceeding $15 million on such claims. Similar schemes have appeared in Indonesia and the Philippines. The fundamental issue is not sophisticated fraud but rather measurement errors: systems that appear to produce excess energy invariably have unaccounted energy inputs (stored chemical energy, ambient heat absorption, or measurement instrument errors) that, when properly accounted for, confirm second-law compliance.

Misapplication of Maximum Efficiency Targets

Policy documents and corporate sustainability reports frequently cite theoretical maximum efficiencies as realistic improvement targets. China's 14th Five-Year Plan for energy, for example, set industrial boiler efficiency targets based on first-law analysis that ignored the thermodynamic quality of energy streams. When Tsinghua University researchers applied exergy analysis to the same systems, they found that approximately 40% of the targeted "waste" heat was at temperatures too low for practical recovery, meaning the policy targets were thermodynamically unachievable. First-law efficiency metrics alone systematically overestimate improvement potential because they treat all energy as equivalent regardless of temperature, pressure, or chemical potential.

Confusion Between Entropy and Disorder

The popular characterization of entropy as "disorder" continues to generate confusion in both public discourse and engineering practice. This metaphor, while useful for introductory education, fails for many real systems. Crystallization, protein folding, and magnetic ordering all represent processes where apparent "order" increases while total entropy also increases (due to heat released to the environment). Engineers who internalize the disorder metaphor sometimes draw incorrect conclusions about process feasibility. The rigorous definition of entropy as a measure of the number of accessible microstates (Boltzmann) or as heat transferred divided by temperature (Clausius) avoids these pitfalls.

Myths vs. Reality

Myth 1: Entropy means everything inevitably decays into chaos

Reality: The second law applies to isolated systems only. Open systems continuously exchange energy and matter with their environment, enabling the spontaneous formation of ordered structures. Every living organism, every hurricane, and every convection cell represents local entropy decrease driven by larger entropy increases elsewhere. Industrial processes are open systems, and skilled engineering can create highly ordered outputs as long as total entropy (system plus environment) increases. The practical implication is that "entropy always increases" should never be used to argue that efficiency improvements are futile.

Myth 2: We are approaching the fundamental thermodynamic limits of energy technology

Reality: While some technologies (like combined-cycle gas turbines) operate within 1-2 percentage points of their theoretical limits, most energy systems have substantial room for improvement. Global average coal plant efficiency is 33%, versus a theoretical limit around 55%. Solar PV modules average 20-22% efficiency against a single-junction theoretical maximum of 33.7% (and much higher for multi-junction designs). Heat pumps achieve COPs of 3-4.5 against Carnot COPs of 15-20 for typical operating conditions. The opportunities for improvement are not marginal; they are substantial, but they require exergy-informed design rather than incremental optimization of existing architectures.

Myth 3: Waste heat recovery always makes economic sense

Reality: Not all waste heat has equal thermodynamic value. Heat at 60 degrees Celsius above ambient contains far less recoverable work (exergy) than the same quantity of heat at 500 degrees Celsius. Second-law analysis reveals that approximately 35-50% of industrial waste heat in the Asia-Pacific region is at temperatures below 100 degrees Celsius, where recovery costs frequently exceed the value of recovered energy. Economically viable waste heat recovery typically requires source temperatures above 150-200 degrees Celsius, where the exergy content justifies investment in recovery equipment. Policies mandating waste heat recovery without temperature-quality thresholds often result in negative-return installations.

Myth 4: Complex systems violate thermodynamic principles through emergence

Reality: Emergence and self-organization in complex systems are fully consistent with the second law. Prigogine's dissipative structures theory shows that complexity arises because of entropy production, not despite it. Systems driven far from equilibrium can spontaneously organize into complex patterns precisely because doing so increases the rate of entropy production for the total system. This has been experimentally confirmed in systems ranging from Benard convection cells to biological evolution. The myth arises from conflating "order" (low entropy of a subsystem) with "violation of the second law" (decrease in total system entropy), which are entirely different statements.

Key Players

Established Leaders

Siemens Energy operates some of the world's most thermodynamically efficient gas turbines, with the SGT-9000HL series achieving over 63% combined-cycle efficiency in commercial deployments across Asia-Pacific.

GE Vernova holds the world record for combined-cycle efficiency at 64.2% and invests heavily in advanced materials and cooling technologies that push closer to Carnot limits.

Mitsubishi Power (now part of Mitsubishi Heavy Industries) has deployed ultra-high-efficiency gas turbines across Japan and Southeast Asia, with a strong research program in hydrogen co-firing that maintains thermodynamic efficiency while reducing carbon intensity.

Emerging Startups

Echogen Power Systems develops supercritical CO2 power cycles that exploit the unique thermodynamic properties of CO2 near its critical point to achieve higher cycle efficiencies than conventional steam Rankine cycles for waste heat recovery applications.

Heliogen uses AI-controlled mirror arrays to achieve solar concentrations exceeding 1,000 degrees Celsius, enabling thermodynamically efficient industrial heat that approaches Carnot limits for high-temperature processes like cement and steel production.

Eavor Technologies, a Canadian geothermal company active in Asia-Pacific markets, uses closed-loop geothermal systems that optimize thermodynamic extraction from geological heat sources without the efficiency losses associated with open-loop hydrothermal systems.

Key Investors and Funders

Japan Science and Technology Agency (JST) funds applied thermodynamics research through its Strategic Innovation Promotion Program, with particular emphasis on exergy-based industrial optimization.

Breakthrough Energy Ventures has invested in multiple companies applying advanced thermodynamic principles to clean energy, including next-generation heat pumps and thermal energy storage.

Asian Development Bank (ADB) finances industrial energy efficiency projects across Southeast Asia that incorporate second-law analysis into project design and performance measurement.

Action Checklist

• Commission exergy audits of major energy-consuming processes, as first-law energy audits systematically overestimate improvement potential
• Train engineering teams on second-law analysis methods, particularly exergy destruction mapping and entropy generation minimization
• Require vendors to provide exergetic efficiency metrics alongside conventional first-law efficiency ratings for new equipment
• Evaluate waste heat recovery projects using exergy content (not just energy content) to avoid investing in low-temperature streams with poor economic returns
• Benchmark facility performance against theoretical thermodynamic limits to identify the subsystems with the largest gap between actual and ideal performance
• Incorporate Carnot and exergy analysis into capital planning models for energy infrastructure investments
• Establish thermodynamic literacy requirements for procurement teams evaluating energy technology vendors
• Review policy compliance targets using second-law analysis to ensure they are physically achievable

FAQ

Q: What is the practical difference between energy efficiency and exergy efficiency? A: Energy efficiency measures total energy output divided by total energy input, treating all forms of energy as equivalent. Exergy efficiency measures useful work output relative to the maximum theoretically extractable work, accounting for energy quality. A low-temperature waste heat stream may contain significant energy but very little exergy (recoverable work). A boiler may have 90% first-law (energy) efficiency but only 40% exergy efficiency, because it converts high-quality chemical energy into relatively low-quality thermal energy. Exergy efficiency reveals the true thermodynamic performance and identifies where the largest improvement opportunities exist.

Q: Can any technology exceed the Carnot efficiency limit? A: No heat engine operating between two thermal reservoirs can exceed the Carnot limit. This is not an engineering constraint but a mathematical consequence of the second law, confirmed by every experiment ever conducted. However, technologies like heat pumps and fuel cells are not heat engines and are not bound by the Carnot efficiency formula for heat engines. A heat pump can deliver 3-6 units of heat per unit of electrical work input because it moves rather than converts thermal energy. Fuel cells convert chemical energy directly to electricity without the Carnot limitation of thermal cycles, though they face their own thermodynamic limits related to Gibbs free energy.

Q: How should engineers evaluate vendor claims about thermodynamic performance? A: Demand exergetic efficiency data alongside first-law efficiency claims. Ask vendors to specify the system boundary used for their efficiency calculations, including all auxiliary power consumption and parasitic loads. Compare claimed performance against the theoretical thermodynamic limit for the specific application and operating conditions. Any claim exceeding 80% of the relevant theoretical maximum deserves scrutiny and independent verification. Claims of "over-unity" performance (efficiency > 100%) should be rejected immediately, as they violate established physical law.

Q: Why does entropy matter for climate and sustainability engineering? A: Every energy conversion and industrial process is constrained by entropy production, which determines the minimum energy input required, the maximum work extractable, and the unavoidable waste heat generated. Climate engineering solutions like carbon capture, hydrogen production, and industrial decarbonization all face thermodynamic minimum energy requirements set by entropy considerations. For example, the theoretical minimum energy to capture CO2 from ambient air at 420 ppm is approximately 20 kJ per mole, set by the entropy of mixing. Real direct air capture systems consume 150-300 kJ per mole, and understanding the thermodynamic floor helps engineers identify which process losses are fundamental and which are engineering challenges with room for improvement.

Q: Is the "heat death of the universe" relevant to engineering decisions? A: No. The thermodynamic heat death hypothesis describes the ultimate far-future state of an isolated universe reaching maximum entropy, on timescales of 10^100 years or more. This has no bearing on any engineering, economic, or policy decision. The Earth is an open system receiving continuous high-quality (low-entropy) energy from the Sun, and will continue to do so for approximately 5 billion years. Engineers should focus on local entropy management within specific system boundaries, not cosmological entropy trends.

Sources

• International Energy Agency. (2025). World Energy Outlook 2025: Asia-Pacific Regional Analysis. Paris: IEA Publications.
• International Renewable Energy Agency. (2025). Renewable Energy Statistics 2025. Abu Dhabi: IRENA.
• Bejan, A. (2024). Advanced Engineering Thermodynamics, 5th Edition. Hoboken, NJ: Wiley.
• Japan Science and Technology Agency. (2025). Strategic Innovation Promotion Program: Industrial Exergy Optimization Results Report. Tokyo: JST.
• Tsinghua University Department of Energy and Power Engineering. (2024). Entropy Generation Minimization in Petrochemical Heat Exchange Networks. Energy, Vol. 298.
• GE Vernova. (2025). 9HA Combined Cycle Performance Validation: 64.2% Net Efficiency Achievement. Atlanta, GA: GE Vernova Technical Publications.
• Prigogine, I. and Stengers, I. (1984). Order Out of Chaos: Man's New Dialogue with Nature. New York: Bantam Books.