Thermodynamics Topics
- Absolute Zero
- At this temperature atoms have no energy.
- Adiabatic Compression
- Compressing a gas without removing or adding heat.
- Adiabatic Cooling
- A method in which paramagnetic salts are pre-cooled, and then demagnetized, thereby producing further cooling.
- Adiabatic Efficiency
- The efficiency with which work is done with respect to heat gains or losses.
- Adiabatic Expansion
- The expansion of a gas, vapour, or liquid stream from a higher pressure to a lower pressure, with no change in enthalpy.
- Adiabatic Line
- A line on an indicator diagram that represents an adiabatic process.
- Adiabatic Process
- A process in which the system does not exchange heat with the surroundings.
- Adiabatic Saturation Process
- A process to determine absolute or relative humidity.
- Aerodynamic Heating
- The heating of a body produced by passage of air or other gases over the body.
- Aerothermodynamic
- A branch of thermodynamics relating to the heating effects associated with the dynamics of a gas.
- Aerothermodynamic Border
- An altitude at about 100 miles, above which the atmosphere is so rarefied that the skin of an object moving through it at high speeds generates no significant heat.
- Aerothermoelasticity
- The study of the response of elastic structures to the combined effect of aerodynamic heating and loading.
- Air Source Heat Pump
- These extract heat directly from the outside air and transfer it to water or air inside the building.
- Antoine Equation
- A simple 3-parameter fit to experimental vapour pressures measured over a restricted temperature range.
- Average Bond Enthalpy
- Average enthalpy change per mole when the same type of bond is broken in the gas phase for many similar substances.
- Bond Enthalpy
- Enthalpy change per mole when a bond is broken in the gas phase for a particular substance.
- Brayton Thermodynamic Cycle
- The thermodynamic cycle of the gas turbine engine. Sometimes known as the Joule Cycle.
- Carnot's theorems
- No engine can be more efficient than a reversible engine working between the same limits of temperature. All reversible engines working between the same two limits of temperature have the same efficiency.
- CHP
- Abbreviation of Combined Heat and Power.
- Chu
- Abbreviation of centigrade heat unit.
- Clausius, Rudolph Julius Emmanuel
- German mathematical physicist; restated the second law of thermodynamics; coined the term "entropy".
- Clausius statement
- No process is possible whose sole result is the transfer of heat from a colder to a hotter body.
- Clausius-Clapeyron Equation
- Predicts the temperature dependence of vapour pressures of pure liquids or solids.
- Coefficient of Performance
- The ratio of cooling or heating to energy consumption.
- Combined Heat and Power
- Electrical power generator set where the waste heat is used to heat water for building heat supply or for industrial processes.
- Conduction
- This is the process by which heat flows from the hotter region of a substance to the colder region without there being any net flow of the material itself.
- Cooling System
- System that extracts heat from a machine and ejects it to the surrounding world.
- CoP
- Abbreviation of Coefficient of Performance.
- Delta T
- A reference to a temperature difference. It is used to describe the difference in temperature of a heating or cooling fluid as it enters and as it leaves a system.
- Dulong-Petit Law
- The molar heat capacity is approximately equal to the three times the ideal gas constant.
- Empirical Temperature
- A property that is the same for any two systems that are in thermodynamic equilibrium with each other.
- Energy Balance
- The difference between the total incoming and total outgoing energy.
- Enthalpy
- Change in heat.
- Enthalpy of Atomization
- The change in enthalpy that occurs when one mole of a compound is converted into gaseous atoms.
- Enthalpy of Combustion
- The amount of energy released in burning completely an amount of substance.
- Enthalpy of Fusion
- The enthalpy change that occurs to melt a solid at its melting point.
- Enthalpy of Hydration
- The enthalpy change associated with placing gaseous molecules or ions in water.
- Enthalpy of Neutralization
- The heat released by an acid-base neutralization reaction running at constant pressure.
- Enthalpy of Reaction
- The heat absorbed or released by a chemical reaction running at constant pressure.
- Enthalpy of Solution
- The enthalpy change associated with dissolving a solute in a solvent.
- Enthalpy of Sublimation
- The change in enthalpy when one mole of solid vaporizes to form one mole of gas.
- Enthalpy of Vaporization
- The change in enthalpy when one mole of liquid evaporates to form one mole of gas.
- Entropy
- Measure of the disorder of a system.
- First Law of Thermodynamics
- ΔU = ΔW + ΔQ
- Forced Heat Convection
- If the flow of gas away from a hot object starts by itself it is called natural convection. However, if the gas is forced past the object it is called forced convection.
- Freezing Point
- The temperature at which the vapour pressure of a liquid is equal to the vapor pressure of the corresponding solid form.
- Freezing Point Depression
- The freezing point of a solution is always lower than the freezing point of the pure solvent.
- Gas Turbine Efficiency
- For a simple cycle gas turbine the efficiency is determined by the pressure ratio of the compressor.
- Ground Source Heat Pump
- The heat is collected using a fluid that flows through pipes laid in the ground.
- Heat
- If a temperature difference exists between two points heat will flow from the point at the higher temperature to the point at the lower temperature. This flow will continue until equilibrium has been reached. The transmission of heat may be due to three different processes.
- Heat Balance
- A tabulation showing the percentages of the heat developed by combustion in the engine cylinder that are (1) delivered in the form of power at the crankshaft, (2) lost in friction, (3) lost to the cooling water, and (4) lost in the exhaust gases.
- Heat Capacity
- The amount of heat required to raise the temperature of a body through 1K.
- Heat Content
- The SI unit for heat content is the Joule per cubic metre.
- Heat Engine
- A device for converting heat into mechanical work.
- Heat Exchanger
- Device built for efficient heat transfer from one medium to another.
- Heat Flow Rate
- The SI unit of heat flow rate or power is the watt.
- Heat of Combustion
- The amount of energy released in burning completely an amount of substance.
- Heat of Fusion
- The enthalpy change that occurs to melt a solid at its melting point.
- Heat of Hydration
- The enthalpy change associated with placing gaseous molecules or ions in water.
- Heat of Neutralization
- The heat released by an acid-base neutralization reaction running at constant pressure.
- Heat of Reaction
- The heat absorbed or released by a chemical reaction running at constant pressure.
- Heat of Solution
- The enthalpy change associated with dissolving a solute in a solvent.
- Heat of Sublimation
- The change in enthalpy when one mole of solid vaporizes to form one mole of gas.
- Heat of Vaporization
- The energy required to vaporize one mole of a liquid at a pressure of one atmosphere.
- Heat Pipe
- A device that can transfer large amounts of heat with a small difference in temperature between the hot and cold interface.
- Heat Pump
- A reversible heat engine that acts as a furnace in winter and an air conditioner in summer.
- Heat Radiation
- This is the electromagnetic radiation emitted by a body as a function of its temperature.
- Heat Transfer
- Movement of heat from one body or substance to another. Heat may be transferred by radiation, conduction, convection or a combination of these three methods.
- Heating Ventilation and Air Conditioning
- Lists all Heating Ventilation and Air Conditioning topics in the Encyclopaedia
- HHV
- Abbreviation of Higher Heating Value.
- Higher Heating Value
- The standard measure of the energy released during combustion of a fuel, assuming the product water is in the liquid state.
- Integral Enthalpy of Solution
- The heat absorbed or released when a solute is dissolved in a definite amount of solvent.
- Isobar
- A contour line that corresponds to values measured at identical pressures.
- Isotherm
- A contour line that corresponds to values measured at identical temperatures.
- Joule Cycle
- The thermodynamic cycle of the gas turbine engine.
- Kelvin
- The kelvin is the unit of thermodynamic temperature.
- Kelvin-Planck statement
- No process is possible whose sole result is the absorption of heat from a reservoir and the conversion of all of this heat into work.
- Latent Heat
- The amount of heat required to melt (or vapourize) 1 kilogram of a substance.
- Latent Heat of Evaporation
- The amount of heat required to vapourize 1 kilogram of a substance.
- Latent Heat of Fusion
- The amount of heat required to melt 1 kilogram of a substance.
- LHV
- Abbreviation of Lower Heating Value.
- Lower Heating Value
- The standard measure of the energy released during combustion of a fuel, assuming the product water is in the gaseous state.
- Miller Cycle
- A combustion process for the four stroke internal combustion engine where the intake valve is left open longer than it would be in an Otto cycle engine.
- Molar Heat Capacity
- The amount of heat required to raise the temperature of 1mol of a substance through 1K.
- Natural Heat
- A term that has generally referred to the heat produced within the body, usually the heat produced by the heart and the circulatory system.
- Natural Heat Convection
- If the flow of gas away from a hot object starts by itself it is called natural convection. However, if the gas is forced past the object it is called forced convection.
- Otto Cycle
- An idealized reversible cycle of four operations occurring in a perfect four-stroke petrol engine.
- Ratio of Specific Heats
- The ratio of molar heat capacity at constant pressure to molar heat capacity at constant volume.
- Second Law of Thermodynamics
- Clausius states: No process is possible whose sole result is the transfer of heat from a colder to a hotter body.
- Simple Cycle Gas Turbine
- Cycle consisting only of compression, combustion and expansion.
- Soil Heat Flux
- The amount of heat flowing into a cross-sectional area of soil per unit time.
- Specific Heat Capacity
- The amount of heat required to raise the temperature of 1kg of a substance through 1K.
- Stagnation Enthalpy
- The total energy or heat content of a system generated when the flow is brought to rest isentropically at a stagnation point.
- Standard Enthalpy Change
- A change in enthalpy associated with a reaction or transformation involving substances in their standard states.
- Standard Enthalpy of Formation
- The change in enthalpy when one mole of compound is formed from its elements in their most stable form and in their standard states.
- Standard Enthalpy of Reaction
- A change in enthalpy associated with a reaction involving substances in their standard states.
- Steam
- The gas phase of water.
- Super Heated Steam
- Steam heated above its saturation temperature.
- Super Heating
- The heating of a liquid above its boiling temperature without the formation of the gaseous phase.
- Superheated Vapour
- Vapour at a temperature which is higher than the saturation temperature at the existing pressure.
- Surroundings
- In thermodynamics, the surroundings refer to the universe outside the system.
- Thermal Conduction
- The transfer of thermal energy by collisions of the atoms or molecules within a substance.
- Thermal Efficiency
- Quantity of heat produced in relation to fuel input.
- Thermodynamic Equilibrium
- A system is at thermodynamic equilibrium if the energy it gains from its surroundings is exactly balanced by the energy it loses, no matter how much time is allowed to pass.
- Thermodynamic Free Energy
- The energy in a physical system that can be converted to do work.
- Thermodynamic Properties
- Basic qualities used in defining the condition of a substance, such as temperature, pressure, volume, enthalpy, entropy.
- Thermodynamics Books
- Lists all Books in the Encyclopaedia
- Thermodynamics Calculations
- Lists all Calculations in the Encyclopaedia
- Thermodynamics Conversions
- Lists all Conversions in the Encyclopaedia
- Thermodynamics Weblinks
- Lists all Weblinks in the Encyclopaedia
- Third Law of Thermodynamics
- For changes involving only perfect crystalline solids at absolute zero, the change of the total entropy is zero.
- Ton Refrigeration Unit
- Unit which removes same amount of heat in 24 hours as melting of 1 ton of ice.
- Vapour Pressure
- The partial pressure of a gas in equilibrium with a condensed form (solid or liquid) of the same substance.
- Vital Heat
- A term that has generally referred to the heat produced within the body, usually the heat produced by the heart and the circulatory system.
- Volume Thermal Expansion
- Relative change in volume due to temperature change.
- Working Fluid
- A fluid used as the medium for the transfer of energy.
- Zero Kelvin
- At this temperature atoms have no energy.
- Zeroth Law of Thermodynamics
- If two bodies are each in thermal equilibrium with a third body, then all three bodies are in thermal equilibrium with each other.
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