Uninsulated or poorly insulated steam pipes are one of the biggest hidden energy losses in businesses. This tool calculates the heat loss per meter and total of the pipe, the amount of condensate created by this loss, the outer surface temperature and the annual energy loss ; it also compares it with the bare state of the same pipe.
Calculation method
Ts: steam temperature, Ta: ambient temperature, d: pipe outer diameter, D: insulation outer diameter, λ: thermal conductivity of the insulation at average temperature, α: outer surface heat transfer coefficient. α is calculated iteratively according to the surface temperature with the relations TS EN ISO 12241 from radiation (cladding emissivity ε) and natural or wind-driven convection.
Example
A 100 m DN100 pipe carrying 10 bar(g) of steam has a heat loss of approximately 72 W/m (7.2 kW in total), a condensate of 13 kg/h, and a surface temperature of 42 °C with 50 mm rock wool and aluminum cladding. If the same pipe were bare, it would lose 1,119 W per meter; insulation prevents 93.5% of the loss. In 6,000 hours of operation per year, this pipe loses 43 MWh of heat even when insulated.
Why is the choice of cladding important?
Low-emissivity coatings, such as polished aluminum, give off less heat by radiation; however, the surface remains warmer. Painted or non-metallic surfaces feel cooler but lose a little more heat. If you know the λ value of the insulation manufacturer, you can enter it in the advanced settings.
Use the economical insulation thickness calculation to find the most suitable thickness. To evaluate your steam system as a whole, you can take a look at our steam boiler guide and get a free quote for your project.