Pipes and Cylinders - Conductive Heat Losses
Conductive heat losses through cylinder or pipe walls.
Uninsulated Cylinder or Pipe
Conductive heat loss through the wall of a cylinder or pipe can be expressed as
Q = 2 π L (ti - to) / [ln(ro / ri) / k] (1)
where
Q = heat transfer from cylinder or pipe (W, Btu/hr)
k = thermal conductivity of piping material (W/mK or W/m oC, Btu/(hr oF ft2/ft))
L = length of cylinder or pipe (m, ft)
π = pi = 3.14...
to = temperature outside pipe or cylinder (K or oC, oF)
ti = temperature inside pipe or cylinder (K or oC, oF)
ln = the natural logarithm
ro = cylinder or pipe outside radius (m, ft)
ri = cylinder or pipe inside radius (m, ft)
Insulated Cylinder or Pipe
Conductive heat loss through an insulated cylinder or pipe can be expressed as
Q = 2 π L (ti - to) / [(ln(ro / ri) / k) + (ln(rs / ro) / ks)] (2)
where
rs = outside radius of insulation (m, ft)
ks = thermal conductivity of insulation material (W/mK or W/m oC, Btu/(hr oF ft2/ft))
Equation 2 with inside convective heat resistance can be expressed as
Q = 2 π L (ti - to) / [1 / (hc ri ) + (ln(ro / ri) / k) + (ln(rs / ro) / ks)] (3)
where
hc = convective heat transfer coefficient (W/m2K)
Related Topics
-
Heat Loss and Insulation
Heat loss from pipes, tubes and tanks - with and without insulation - foam, fiberglass, rockwool and more. -
Insulation
Heat transfer and heat loss from buildings and technical applications - heat transfer coefficients and insulation methods to reduce energy consumption. -
Thermodynamics
Thermodynamics of steam and condensate systems.
Related Documents
-
Butane - Thermal Conductivity vs. Temperature and Pressure
Online calculators, figures and tables showing thermal conductivity of liquid and gaseous butane, C4H10, at varying temperature and pressure, SI and Imperial units. -
Conductive Heat Transfer
Conductive heat transfer takes place in a solid if there is a temperature gradient. -
Copper Tubes - Heat Losses
Heat loss from uninsulated copper tubes vs. temperature differences between tube and air. -
Copper Tubes - Uninsulated Heat Losses
Heat loss from uninsulated copper pipes - dimensions ranging 1/2 - 4 inches. -
Ethane - Thermal Conductivity vs. Temperature and Pressure
Online calculator, figures and table showing thermal conductivity of ethane, C2H6, at varying temperature and pressure - Imperial and SI Units. -
Ethylene - Thermal Conductivity vs. Temperature and Pressure
Online calculator, figures and table showing thermal conductivity of ethylene, also called ethene or acetene, C2H4, at varying temperature and pressure - Imperial and SI Units. -
Hydrogen - Thermal Conductivity vs. Temperature and Pressure
Online calculator, figures and table showing thermal conductivity of hydrogen, H2, at varying temperature and pressure - Imperial and SI Units. -
Insulated Copper Tubes - Heat Loss
Heat loss to surrounding air from insulated copper tubes. -
Nitrogen - Thermal Conductivity vs. Temperature and Pressure
Online calculator, figures and tables showing thermal conductivity of nitrogen, N2, at varying temperarure and pressure, SI and Imperial units. -
Oil Filled Tanks - Heat Loss
Heat loss from insulated and uninsulated, sheltered and exposed heated oil tanks. -
Oil Pipes - Heat Loss
Heat loss in W/mK and Btu/hr ft oF from oil tubes ranging temperatures 10 - 38oC (50 - 100oF). -
Pipes - Bare Surface Heat Loss
Heat loss vs. surface temperature. -
Pipes - Insulated Heat Loss Diagrams
Heat loss (W/m) from 1/2 to 6 inches insulated pipes - ranging insulation thickness 10 to 80 mm and temperature differences 20 to 180 oC. -
Pipes - Insulated Heat Loss Diagrams
Heat loss (W/ft) diagrams for 1/2 to 6 inches insulated pipes - ranging insulation thickness 0.5 to 4 inches and temperature differences 50 to 350 oF. -
Pipes Submerged in Oil or Fat - Heat Emission
Heat emission from steam or water heating pipes submerged in oil or fat - forced and natural circulation. -
Pipes Submerged in Water - Heat Emission
Heat emision from steam or water heating pipes submerged in water - assisted (forced) or natural circulation. -
Piping - Recommended Insulation Thickness
Recommended insulation thickness for heating systems like hot water and low, medium or high pressure steam systems. -
Propane - Thermal Conductivity vs. Temperature and Pressure
Online calculator, figures and tables showing thermal conductivity of liquid and gaseous propane at varying temperarure and pressure, SI and Imperial units. -
Solids, Liquids and Gases - Thermal Conductivities
Thermal conductivity coefficients for insulation materials, aluminum, asphalt, brass, copper, steel, gases and more. -
Steam Pipes - Heat Losses
The amount of condensate generated in a steam pipe depends on the heat loss from the pipe to the surroundings. -
Steam Pipes - Heat Losses (W/m)
Heat losses from un-insulated steam pipes. -
Steel Pipes - Heat Loss Diagram
Heat loss from steel pipes and tubes - dimensions 1/2 to 12 inches. -
Thermal Resistivity and Conductivity
The ability of a material to resist flow of heat. -
Water - Thermal Conductivity vs. Temperature
Figures and tables showing thermal conductivity of water (liquid and gas phase) with varying temperature and pressure, SI and Imperial units.
