Which of the three methods for calculating the thickness of insulating layers is the most accurate?
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This post was last edited by feng_200108047 on 2011-7-8 at 15:34. I have been recently calculating the thickness of thermal insulation layers, but there are three methods available: 1. Calculating it by controlling the temperature of the outer surface of the insulation layer; 2. Calculating it by controlling the maximum heat loss; 3. Calculating it based on the thickness of the insulation layer required to achieve a certain temperature drop. Which method is more accurate? How do you calculate the insulation thickness? Are there any resources or convenient methods available? It would be great if there were pre-calculated values that I could refer to, as I’m not sure which method to use.
Reply to 1# — Lantian — We don’t do any calculations; there are tables available indicating which thickness of insulation is required in different situations.
Reply to 2# 03110205chen: Where is the table? Is it accurate or not?
Insulation and protection are not the same as thermal insulation. In simple terms, it involves keeping heat in or preventing heat from escaping. Check relevant sources in chemical engineering design – design firms provide more specific explanations on this
Reply to 4# TH373637: Protection and insulation are different; protection refers to the covering layer, while insulation is the same thing, right? Heat retention or insulation is a matter of which factor takes precedence – whether energy moves from inside to outside or from outside to inside. Hehe, that’s how it’s calculated in the books I’ve read. Posts shouldn’t disappear; why isn’t anyone answering them every time? . .
Reply 1# —Lantian— Personally, I think it should be calculated based on the maximum allowable heat loss. LZ, take a look at these two specifications. The commonly used standards for design purposes are SH 3010-2000 \"Technical Specifications for Insulation of Petrochemical Equipment and Piping\" and GB/T 8175-87 \"Guidelines for the Design of Insulation for Equipment and Piping\"; they can be downloaded for free from the Standard Sharing Network.
Reply to 6# yangke: There is actually another method, which is to calculate the thickness using the economic thickness approach – by calculating the heat transfer through thermal resistance. It turns out that everyone uses this method for calculations; it’s really confusing. The calculations are already complicated enough, and doing them twice would be unbearable. .
Reply to 6# yangke: I’ve read everything you mentioned. I’ve also read \"Design and Installation of Process Piping in Petrochemical Industries\", and the content is pretty similar; the differences aren’t that significant, aside from a few different methods used. .
If idealized, the calculation of heat retention should not be difficult, as there are formulas available for that purpose. The key issue is that any device or system always has supporting structures or external components, which means there are heat bridge losses. Therefore, accurately estimating or calculating these heat bridge losses is what’s most challenging.
Reply to 9# YQQCJXL: Even once it’s determined, there are still numerous factors to take into account, and derivatives are also required during the calculation process. Do you think that’s simple? You haven’t calculated it, have you?
Calculations can be performed using EXCEL; generally, the thickness is first determined based on the maximum heat dissipation amount, and then rounded off to calculate the temperature rise on the insulated surface. Of course, calculate it using the economic thickness