Symbols

Units

l

Length

m

b

Width

m

h

Height

m

Thickness

m

r

Radius

m

d

Diameter

m

A

Area

m²

V

Volume

m³

Symbols

Units

C_P

Specific heat capacity

kJ/kg · K

C

Coefficient of radiation

W/m² · K⁴

d_h

Hydraulic diameter

m

d_e

Equivalent diameter

m

E

Energy

J

F

Force

N

g

Acceleration due to gravity

m/s²

h

Enthalpy

J/kg

m

Mass

kg

P

Power

W = J/s

Pr

Prandtl´s number

p

Pressure

Pa = N/m²

p_d

Dynamic pressure

Pa

p_s

Static pressure

Pa

p_atm

Atmospheric pressure

Pa, mbar

p_t

Total pressure

Pa

Dp

Pressure differential

Pa

q

Volume flow

m³/s

r

Heat of vaporisation

kJ/kg

R

Heat resistance

m² · K/W

T

Temperature, Kelvin

K

t

Temperature, Celsius

°C

t

Time

s

DT

Temperature difference

K

Dt

Temperature difference

°C

U

Heat transfer coefficient

W/m 2 · K

v

Velocity

m/s

Heat transition coefficient

W/m² · K

Emission factor, efficiency

Kinetic viscosity

m²/s

Density

kg/m³

Relative humidity

%

Efficiency

Heat conduction factor

W/m · °C

Symbols

Units

A

Absorption area

m² Sabine

c

Speed of sound

m/s

D

Level difference

dB

f

Frequency

Hz

i

Intensity

W/m²

L

Sound level

dB ref 2·10^-5 Pa

L_A

A-weighted sound
pressure level

dB ref 2·10^-5 Pa

L_P

Pressure level

dB ref 2·10^-5 Pa

L_W

Sound pressure level

dB ref 10^-12 W

L_WA

A-weighted sound
power level

dB ref 10^-12 W

L_i

Sound intensity level

dB ref 10 -12 W/m²

L_eq

Equivalent sound level

dB ref 2·10^-5 Pa

Q

Directionality factor

R

Room constant

R

Reduction factor

dB

T

Resonance time

s

Absorption factor

Wavelength

m