Seek help: in cold insulation calculations, the economic thickness is greater than the allowable loss thickness
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I need help. As stated in the question, if the economic thickness ratio is greater than the allowable loss thickness in the heat insulation calculation, is it a mistake in my calculations, or is it possible for the economic thickness ratio to be greater than the allowable loss thickness? Also, how should the thickness of the heat insulation material be determined?
This post was last edited by bfdlwolf on 2016-1-21 at 11:59. SH3010 stipulates: “For the calculation of the thickness of the insulation layer, the following principles shall be followed: 1. To minimize heat loss, the economic thickness method should be used to determine the thickness......” “For the calculation of the thickness of the thermal insulation layer, the following principles shall be followed: 1. If there are no special requirements from the manufacturing process, the economic thickness method should be applied; however, if this economic thickness is too small and the heat loss exceeds the maximum allowable level, then the formula based on the maximum allowable heat loss should be used for verification.” Similar provisions can be found in other standards as well. It is clear, therefore, that the standards set different requirements for calculating the thickness of insulation layers and thermal insulation layers. The original poster should clarify whether they are dealing with the calculation of the thickness of an insulation layer or a thermal insulation layer. There is no such thing as an “allowed loss thickness” in the calculation of the insulation layer thickness; could the original poster be mistaken?
So, it means that there is only one way to calculate the thickness of the insulation layer, which is using the economic thickness method, right?
No, there are the economic thickness method, surface temperature method, and thermal equilibrium method. To reduce heat loss, the thickness of the insulation layer should be calculated using the economic thickness method ； The thickness of the insulation layer intended to prevent dew formation on the outer surface should be calculated using the surface temperature method ； For insulation layers that allow a certain amount of heat loss in terms of manufacturing considerations, the thickness should be calculated using the heat balance method, and it is necessary to ensure that the surface temperature is 1–3 degrees higher than the dew point temperature℃
There are many algorithms, but generally we calculate based on economic thickness. Unless there are special requests.