Engineers or designers who need to transport hot fluids through pipe over a distance need to account for the natural heat loss that will occur along the way. These thermodynamic calculations can be quite complex unless certain assumptions are made, one being steady conditions and the other a lack of convection in the area of the pipe. Fortunately, for most practical applications these assumptions are valid and will allow for accurate results.
Determine the thermal conductivity, also known as the heat transfer coefficient, of the pipe material for which you are calculating heat loss. A link to a table with the values for most common pipe materials can be found in Resources.
Record the expected temperatures of the fluid to be transported through the pipe, and the air temperature outside of the pipe.
Use the following equation and simply substitute in the appropriate values:
Q= 2 (pi) k * L(T1-T2)/ [ln(r2/r1)]
where k= the heat transfer coefficient of the pipe material,
T1= the inside temperature of the pipe, which can be assumed to be the same as the fluid temperature,
T2= the outside temperature of the pipe, which can be assumed to be the same as the air temperature outside the pipe,
L= the length of pipe over which the fluid will be transported,
r1= inner radius of the pipe,
r2=outer radius of the pipe,
and the final value will yield the heat loss in the pipe. Use consistent units in your calculation; a proper calculation will yield a result expressed in heat loss per linear distance, such as watts per foot.
- Photo Credit pipe image by Artur Blaszak from Fotolia.com
The Temperature of a Steam Pipe
A steam pipe is simply a conveyance for steam. The steam is generally used to power an engine, whether it be a...
How to Calculate Heat Loss During Pipeline Depressurization
When a pressurized gas pipeline is rapidly depressurized (i.e., the gas is allowed to flow rapidly through an open valve to atmosphere),...
How to Insulate Pex
Insulating Pex pipe is no different than insulating around copper or iron pipe. The easiest and most economical form of pipe insulation...
How to Calculate Head Loss
Head loss is a common term used to describe two types of pressure loss in a liquid system. The first type is...
How to Insulate Heating Pipes
Insulating heating pipes is a great way to keep your heating system energy efficient. Pipes that are not insulated quickly transfer heat...
How to Calculate Heat Loss Through Windows
To determine a building’s energy efficiency, you can calculate heat losses from the structure. In a home or building, heat losses during...
How to Calculate for Heat Loss
Heat loss can be calculated manually or by using an automatic calculator or an online heat loss calculator. The transfer of heat...
How to Calculate Insulation Energy Savings for Bare Pipe
Pipes that carry hot liquid and gases will lose heat energy to their surroundings unless they are insulated. Insulation materials cost money---but...
How to Do Heat Loss Calculations for HVAC Systems
Homeowners and HVAC technicians use heat loss calculations to determine the heating system size necessary to maintain the most comfortable indoor environment...
Does Wind Chill Affect Objects Like Metal?
Wind chill refers to how fast the body loses heat when exposed to cold temperatures and wind. The colder the temperature and...
Steam Pipe Installation
Installing pipes for carrying steam involves certain considerations not necessarily applicable to other piping systems. Of course, the major difference is the...