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Source– This post on How heat impacts our lives is based on the article “What is heat? How does it animate engines and global warming?” published in “The Hindu” on 11th June 2024.
Why in the News?
Increasing global warming compels us to reconsider how heat impacts our lives.
About Heat:
1. Definition of Heat:
i) Microscopic View: An object’s temperature is the average kinetic energy of its particles. Heat is the thermal energy exchanged between two bodies at different temperatures.
ii) Macroscopic View: Heat is treated as a form of energy characterized using thermodynamics and statistical mechanics.
2. Heat Transfer:
i) When two bodies at different temperatures come into contact, heat flows from the hotter body to the cooler one until thermal equilibrium is reached.
ii) A medium can absorb heat in one location and release it in another, which is the basis for technologies like thermal power plants and air conditioning.
3. Conversion of Heat to Mechanical Energy:
i) Internal Combustion Engines (ICEs): This convert heat to work using the Carnot cycle, which has four steps: isothermal expansion, isentropic expansion, isothermal compression, and isentropic compression.
ii) Thermal Power Plants: Its operation is based on the Rankine cycle, involving four steps: isentropic compression, heat addition, isentropic expansion, and heat removal.
Note: Carnot Cycle describes the maximum efficiency of heat engines and Rankine Cycle is ideal form for thermal power plants.
About Applications of Heat:
1. In Industrial feild, heat is used in metallurgy, mining and refineries, chemical Reactions and semiconductor electronics.
2. It is used for centralized heating for homes and offices.
3. It is used in internal Combustion Engines (ICEs) and steam engines.
4. It is also used in transportation in the form of internal combustion engines in vehicles and aircraft and also thermal management in electric vehicles.
Heat role in climate change
i) Heat plays a central role in climate change through both mitigation and adaptation strategies.
ii) Effective management of heat production and adaptation to heat waves are essential to combat the adverse effects of climate change.
iii) The greenhouse effect is a key mechanism by which heat is implicated in global warming.
UPSC Syllabus: Science and technology
