# [TECH] Steam Engine & Heat Engines
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**The Steam Engine** is the first practical technology for converting heat into mechanical work, developed by Watt, Newcomen, and others (1712–1790), and the foundational technology of the Industrial Revolution.
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## Overview
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Thomas Newcomen's atmospheric engine (1712) pumped water from mines. James Watt's improvements (1769 patent: separate condenser; 1782: double-acting engine; 1784: rotary motion) made the steam engine a general-purpose prime mover. By 1800 Boulton & Watt had sold over 400 engines; by 1850 steam power in Britain exceeded 1 million horsepower.
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The steam engine preceded formal thermodynamics — it motivated Carnot's analysis. The engine also created demand for precision machining, fuelling the machine tool industry and enabling the manufacture of other precision machinery.
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## Key Actors
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- **Companies**: Boulton & Watt (UK, 1775); Stephenson (locomotives, 1814); Corliss Engine Co. (US)
- **Inventors**: Thomas Newcomen (1664–1729), James Watt (1736–1819), Richard Trevithick (1771–1833)
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## Key Patents
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- Watt, J. UK Patent No. 913 (1769) — separate condenser
- Watt, J. UK Patent No. 1321 (1782) — rotary motion & double-acting engine
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## Economic Value
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The steam engine enabled the Industrial Revolution, which increased UK GDP roughly 14× between 1700 and 1870 and transformed global trade. Economists estimate the cumulative GDP gain from industrialisation attributable to steam at **$30–60 trillion** over two centuries (present-value adjusted estimates vary widely). Modern steam turbines generate ~80% of world electricity (~$2T/year generation revenue).
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## Notes
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Crafts & Harley (1992) estimate TFP growth from steam at 0.3–0.5% per year across the UK economy, 1760–1840. Weil (2012, *Economic Growth*) attributes ~25% of 19th-century UK productivity growth to steam. Modern gas/steam turbines: IEA World Energy Outlook 2023.
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# Parents
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* [SCI] Classical Thermodynamics⏎