Heat exchanger insulation thickness

[MichaelDexter]

Hello
Do you have any simple way (program ) to calculate heat exchanger insulation thickness ?

I have shell temperature 180 deg C, shell diameter OD 610mm and I am looking for standard insulation thickness (using for example mineral wool) My preliminary assumption is temperature 30 deg C on external insulation surface

I didn't make it, it is my first time.

Unfortunately program on website

http://www.pipeinsulation.org/

doesn't work , and calculation on

http://www.kaimann.de/

is strange for me

 

[georgeverghese]

Optimum insulation thickness calcs should be based on the cost of the utility used to generate the heat lost.

Simple way of doing this would be to use a payback period of 3-5years

Prepare a graph with total cost over 5 years on the y axis and thickness on the x axis.

Total cost = Total installed cost of the insulation + cost of the utility (over 5 years) required to generate the heat corresponding to the heat loss at that insulation thickness.

Plot this out over a several thicknesses and you will see a minimum in the curve, which is the optimum thickness.

Presume you know how to calculate the heat loss over the HX external suraface area for each thickness.

 

[TD2K]

As George said, there's no such thing as standard insulation thickness, it depends on the cost of energy and the cost of insulation, type of insulation, ambient temperatures with a desired pay-back.

If you want a quick way, look up the thermal conductivity of mineral wool. Calculate the heat flow through the insulation for 1", 1.5", 2", 2.5", etc and see where the point of dimishing returns is. I'd estimate for most of the insulation thickness tables I've seen, you would be between 2" and 3" of insulation at that temperature.

 

[racookpe1978]

Further, as the thickness of insulation increases - obviously the weight, the cost, and time to install it increases. But also, the outside diameter of the final heat transfer surface also increases. Thus, the surface area losing heat to the room/environment increases, even though the surface temperature of that increased area decreases.

At some point - different for every pipe or pressure vessel and cost-of-heat-loss! - the extra insulation is not saving yo any money over time.