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Part 5: Thermodynamics

Temperature, heat, entropy

54 entries· Edition 2019FR→ About this part

5-1thermodynamic temperature

T

Θ

K

·kelvin

partial derivative of internal energy with respect to entropy at constant volume and constant number of particles in the system: where is…

5-2Celsius temperature

5-2

Celsius temperature

t

ϑ

d e g C

·degree Celsius

temperature difference from the thermodynamic temperature of the ice point is called the Celsius temperature , which is defined by the…

5-3linear expansion coefficient

5-3.1

linear expansion coefficient

α_{l}

K^{- 1}

·per kelvin

relative change of length with temperature: where is length (iso80000-3) and is thermodynamic temperature (t5-1)

5-3.2

cubic expansion coefficient

α_{V}

γ

K^{- 1}

·per kelvin

relative change of volume with temperature: where is volume (iso80000-3) and is thermodynamic temperature (t5-1)

5-3.3

relative pressure coefficient

α_{p}

K^{- 1}

·per kelvin

relative change of pressure with temperature at constant volume: where is pressure (iso80000-4), is thermodynamic temperature (t5-1), and…

5-4pressure coefficient

5-4

pressure coefficient

β

P \frac{a}{K}

k g \cdot m^{- 1} \cdot s^{- 2} \cdot K^{- 1}

·pascal per kelvin, kilogram per metre second squared kelvin

change of pressure with temperature at constant volume: where is pressure (iso80000-4), is thermodynamic temperature (t5-1), and is volume…

5-5isothermal compressibility

5-5.1

isothermal compressibility

κ_{T}

P a^{- 1}

k g^{- 1} \cdot m \cdot s^{2}

·per pascal, metre second squared per kilogram

negative relative change of volume with pressure at constant temperature: where is volume (iso80000-3), is pressure (iso80000-4), and is…

5-5.2

isentropic compressibility

κ_{S}

P a^{- 1}

k g^{- 1} \cdot m \cdot s^{2}

·per pascal, metre second squared per kilogram

negative relative change of volume with pressure at constant entropy: where is volume (iso80000-3), is pressure (iso80000-4), and is…

5-6heat, amount of heat

5-6.1

heat, amount of heat

Q

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

difference between the increase in the internal energy (t5-20.2) of a system and the work (iso80000-4) done on the system, provided that…

5-6.2

latent heat

Q

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

energy released or absorbed by a system during a constant-temperature process

5-7heat flow rate

5-7

heat flow rate

\dot{Q}

W

\frac{J}{s}

k g \cdot m^{2} \cdot s^{- 3}

·watt, joule per second, kilogram square metre per second cubed

time rate at which heat (t5-6.1) crosses a given surface

5-8density of heat flow rate

5-8

density of heat flow rate

q

φ

\frac{W}{m^{2}}

k g \cdot s^{- 3}

·watt per square metre, kilogram per second cubed

quotient of heat flow rate and area: where is heat flow rate (t5-7) and is area (iso80000-3) of a given surface

5-9thermal conductivity

5-9

thermal conductivity

λ

(κ)

\frac{W}{m \cdot K}

k g \cdot m \cdot s^{- 3} \cdot K^{- 1}

·watt per metre kelvin, kilogram metre per second cubed kelvin

quotient of density of heat flow rate (t5-8) and thermodynamic temperature gradient that has the same direction as the heat flow

5-10coefficient of heat transfer

5-10.1

coefficient of heat transfer

K

(k)

\frac{W}{m^{2} \cdot K}

k g \cdot s^{- 3} \cdot K^{- 1}

·watt per square metre kelvin, kilogram per second cubed kelvin

quotient of density of heat flow rate (t5-8) and thermodynamic temperature (t5-1) difference

5-10.2

surface coefficient of heat transfer

h

(α)

\frac{W}{m^{2} \cdot K}

k g \cdot s^{- 3} \cdot K^{- 1}

·watt per square metre kelvin, kilogram per second cubed kelvin

quotient of density of heat flow rate and the difference of the temperature at the surface and a reference temperature: where is density of…

5-11thermal insulance, coefficient of thermal insulance

5-11

thermal insulance, coefficient of thermal insulance

M

m^{2} \cdot \frac{K}{W}

k g^{- 1} \cdot s^{3} \cdot K

·square metre kelvin per watt, second cubed kelvin per kilogram

inverse of coefficient of heat transfer : where is coefficient of heat transfer (t5-10.1)

5-12thermal resistance

5-12

thermal resistance

R

\frac{K}{W}

k g^{- 1} \cdot m^{- 2} \cdot s^{3} \cdot K

·kelvin per watt, second cubed kelvin per kilogram square metre

quotient of thermodynamic temperature (t5-1) difference and heat flow rate (t5-7)

5-13thermal conductance

5-13

thermal conductance

G

(H)

\frac{W}{K}

k g \cdot m^{2} \cdot s^{- 3} \cdot K^{- 1}

·watt per kelvin, kilogram square metre per second cubed kelvin

inverse of thermal resistance : where is thermal resistance (t5-12)

5-14thermal diffusivity

5-14

thermal diffusivity

a

m^{2} \cdot s^{- 1}

·square metre per second

quotient of thermal conductivity and the product of mass density and specific heat capacity: where is thermal conductivity (t5-9), is mass…

5-15heat capacity

5-15

heat capacity

C

\frac{J}{K}

k g \cdot m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kelvin, kilogram square metre per second squared kelvin

derivative of added heat with respect to thermodynamic temperature of a system: where is amount of heat (t5-6.1) and is thermodynamic…

5-16specific heat capacity

5-16.1

specific heat capacity

c

\frac{J}{k g \cdot K}

m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kilogram kelvin, square metre per second squared kelvin

quotient of heat capacity and mass: where is heat capacity (t5-15) and is mass (iso80000-4)

5-16.2

specific heat capacity at constant pressure

c_{p}

\frac{J}{k g \cdot K}

m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kilogram kelvin, square metre per second squared kelvin

specific heat capacity (t5-16.1) at constant pressure (iso80000-4)

5-16.3

specific heat capacity at constant volume

c_{V}

\frac{J}{k g \cdot K}

m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kilogram kelvin, square metre per second squared kelvin

specific heat capacity (t5-16.1) at constant volume (iso80000-3)

5-16.4

specific heat capacity at saturated vapour pressure

c_{sat}

\frac{J}{k g \cdot K}

m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kilogram kelvin, square metre per second squared kelvin

specific heat capacity (t5-16.1) at saturated vapour pressure (iso80000-4)

5-17ratio of specific heat capacities

5-17.1

ratio of specific heat capacities

γ

1

·one

quotient of specific heat capacity at constant pressure and specific heat capacity at constant volume: where is specific heat capacity at…

5-17.2

isentropic exponent, isentropic expansion factor

κ

1

·one

the negative of relative pressure change, divided by relative volume change, at constant entropy: where is volume (iso80000-3), is pressure…

5-18entropy

5-18

entropy

S

\frac{J}{K}

k g \cdot m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kelvin, kilogram square metre per second squared kelvin

natural logarithm of number of equally probable microscopic configurations in a macroscopic system, multiplied by the Boltzmann constant:…

5-19specific entropy

5-19

specific entropy

s

\frac{J}{k g \cdot K}

m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kilogram kelvin, square metre per second squared kelvin

quotient of entropy and mass: where is entropy (t5-18) and is mass (iso80000-4)

5-20energy <thermodynamics>

5-20.1

energy

E

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

ability of a system to do work (iso80000-4)

5-20.2

internal energy, thermodynamic energy

U

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

energy of a system whose change is given by the amount of the heat (t5-6.1) transferred to the system and the work (iso80000-4) done on the…

5-20.3

enthalpy

H

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

sum of internal energy of the system and the product of pressure and volume of the system: where is internal energy (t5-20.2), is pressure…

5-20.4

Helmholtz energy, Helmholtz function

A

F

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

difference of internal energy of the system and the product of thermodynamic temperature and entropy of the system: where is internal…

5-20.5

Gibbs energy, Gibbs function

G

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

difference of the enthalpy and the product of thermodynamic temperature and entropy of the system: where is enthalpy (t5-20.3), is…

5-21specific energy

5-21.1

specific energy

e

\frac{J}{k} g

m^{2} \cdot s^{- 2}

·joule per kilogram, square metre per second squared

quotient of energy and mass: where is energy (t5-20.1) and is mass (iso80000-4)

5-21.2

specific internal energy, specific thermodynamic energy

u

\frac{J}{k} g

m^{2} \cdot s^{- 2}

·joule per kilogram, square metre per second squared

quotient of internal energy and mass: where is internal energy (t5-20.2) and is mass (iso80000-4)

5-21.3

specific enthalpy

h

\frac{J}{k} g

m^{2} \cdot s^{- 2}

·joule per kilogram, square metre per second squared

quotient of enthalpy and mass: where is enthalpy (t5-20.3) and is mass (iso80000-4)

5-12specific Helmholtz energy, specific Helmholtz function

5-12.4

specific Helmholtz energy, specific Helmholtz function

a

f

\frac{J}{k} g

m^{2} \cdot s^{- 2}

·joule per kilogram, square metre per second squared

quotient of Helmholtz energy and mass: where is Helmholtz energy (t5-20.4) and is mass (iso80000-4)

5-21specific Gibbs energy, specific Gibbs function

5-21.5

specific Gibbs energy, specific Gibbs function

g

\frac{J}{k} g

m^{2} \cdot s^{- 2}

·joule per kilogram, square metre per second squared

quotient of Gibbs energy and mass: where is Gibbs energy (t5-20.5) and is mass (iso80000-4)

5-22Massieu function

5-22

Massieu function

J

\frac{J}{K}

k g \cdot m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kelvin, kilogram square metre per second squared kelvin

quotient of the negative of Helmholtz energy and temperature: where is Helmholtz energy (t5-20.4) and is thermodynamic temperature (t5-1)

5-23Planck function

5-23

Planck function

Y

\frac{J}{K}

k g \cdot m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kelvin, kilogram square metre per second squared kelvin

quotient of the negative of Gibbs energy and temperature: where is Gibbs energy (t5-20.5) and is thermodynamic temperature (t5-1)

5-24Joule-Thomson coefficient

5-24

Joule-Thomson coefficient

μ_{JT}

\frac{K}{P} a

k g^{- 1} \cdot m \cdot s^{2} \cdot K

·kelvin per pascal, metre second squared kelvin per kilogram

change of thermodynamic temperature with respect to pressure in a Joule-Thomson process at constant enthalpy: where is thermodynamic…

5-25efficiency <thermodynamics>

5-25.1

efficiency

η

1

·one

quotient of work (iso80000-4) delivered by a heat engine and supplied heat: where is work (iso80000-4) and is heat (t5-6.1)

5-25.2

maximum efficiency

η_{max}

1

·one

efficiency determined by the quotient of the temperatures of the hot source and the cold sink: where is the thermodynamic temperature…

5-26specific gas constant

5-26

specific gas constant

R_{s}

\frac{J}{k g \cdot K}

m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kilogram kelvin, square metre per second squared kelvin

quotient of the Boltzmann constant (iso80000-1) and the mass (iso80000-4) of the gas particle

5-27mass concentration of water

5-27

mass concentration of water

w

k g \cdot m^{- 3}

·kilogram per cubic metre

quotient of mass of water and a specified volume: where is mass (iso80000-4) of water, irrespective of the form of aggregation state, and…

5-28mass concentration of water vapour, absolute humidity

5-28

mass concentration of water vapour, absolute humidity

v

k g \cdot m^{- 3}

·kilogram per cubic metre

quotient of mass of water vapour and a specified volume: where is mass (iso80000-4) of water vapour and is volume (iso80000-3)

5-29mass ratio of water to dry matter

5-29

mass ratio of water to dry matter

u

1

·one

quotient of mass of water and mass of dry matter: where is mass (iso80000-4) of water and is mass of dry matter

5-30mass ratio of water vapour to dry gas

5-30

mass ratio of water vapour to dry gas

r

(x)

1

·one

quotient of mass of water vapour and mass of dry gas: where is mass (iso80000-4) of water vapour and is mass of dry gas

5-31mass fraction of water

5-31

mass fraction of water

w_{H_{2} O}

1

·one

quantity given by: where is mass ratio of water to dry matter (t5-29)

5-32mass fraction of dry matter

5-32

mass fraction of dry matter

w_{d}

1

·one

quantity given by: where is mass fraction of water (t5-31)

5-33relative humidity

5-33

relative humidity

φ

1

·one

quotient of partial pressure of water vapour and partial pressure at its saturation: where is partial pressure (iso80000-4) of vapour and…

5-34relative mass concentration of vapour

5-34

relative mass concentration of vapour

φ

1

·one

quotient of mass concentration of water vapour and mass concentration at its saturation: where is mass concentration of water vapour…

5-35relative mass ratio of vapour

5-35

relative mass ratio of vapour

ψ

1

·one

quotient of mass ratio of water vapour to dry gas and mass ratio of water vapour to dry gas at saturation: where is mass ratio of water…

5-36dew-point temperature

5-36

dew-point temperature

T_{d}

K

·kelvin

temperature at which water vapour in the air reaches saturation under isobaric conditions

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