https://engineers.academy/product-category/level-3-courses/level-3-national-diploma-nd-courses/ Level 3 Engineering Principles - Thermodynamic Systems Equations Sheet

1. LEVEL 3 ENGINEERING PRINCIPLES – THERMODYNAMIC SYSTEMS EQUATIONS
Heat Transfer Equations
Subject Equation Variables and Units
Heat Transfer Q = mCΔT
Q = heat energy in Joules (J)
m = mass in kilograms (kg)
C = specific heat capacity in Joules per
kilogram Kelvin (J/KgK)
ΔT = change in temperature in
degrees Kelvin (K)
Lv = latent heat of vaporisation in
Joules per kilogram (J/kg)
Lf = latent heat of fusion in Joules per
kilogram (J/kg)
P = thermal power in Watts (W)
t = time in seconds (s)
Heat Required for
Change of State
Q = ml
Q = ml
Thermal Power P =
Q
t
Thermal Expansion Equations
Subject Equation Variables and Units
Change in Length ΔL = αL ΔT
ΔL = change in length (m)
α = thermal expansion coefficient (K-1
)
Lo = original length in meters (m)
ΔT = change in temperature in
degrees Kelvin (K)
L = length (m)
New Length L = L + ΔL

2. Gas Laws
Subject Equation Variables and Units
General Gas
Equation
PV
T
= C
P = pressure in pascals (Pa)
V = volume in cubic meters (M3
)
T = temperature in Kelvin (K)
C = arbitrary constant
m = mass of gas in kilograms (kg)
R = specific gas constant (J/Kg)
P V
T
=
P V
T
Ideal Gas Law PV = mRT
Heat Transfer in Gases
Subject Equation Variables and Units
Change in
Internal Energy
ΔU = m𝐶 ΔT
ΔU = change in internal energy in Joules (J)
ΔH = change in enthalpy in Joules (J)
m = mass in kilograms (kg)
Cv = specific heat capacity at constant
volume in Joules per kilogram Kelvin (J/KgK)
Cp = specific heat capacity at constant
pressure in Joules per kilogram Kelvin (J/KgK)
ΔT = change in temperature in
degrees Kelvin (K)
W = work done in Joules (J)
P = pressure in pascals (Pa)
ΔV = change in volume in cubic meters (m3
)
Change in
Enthalpy
ΔH = m𝐶 ΔT
ΔH = ΔU + W
(where 𝑊 = 𝑃𝛥𝑉)