Dear All,
My qurey is regarding storage tank heat loss calculation. I have prepared excel sheet for the calculation using the article published by Jimmy D Kumana and Samir P Kothari i.e. Predict storagetank heat transfer precisely. I do have this article in pdf format but not attached as not sure if I would breach any copyright policy, however it would make easy to understand and compare my calculation with the article if I do so. I would like to attach with the permission of Art/moderator. Problem description and query are as below.
Problem Description:
Six Storage tanks [rectangle in shape] are filled up with Isopropanaol (liquid 1) at the initial temperature of 45 deg C and it is required to maintain the liquid temperature at 30 deg C. All the tanks are placed adjacent to each other with minor gap in between. Tanks are stored in a closed building maintained at room temperature let's say 10 deg C and a wind speed of around 2miles/hr.How long will it take to drop down temperature from 45 to 30 deg C with/without insulation OR after what time tanks are required to heat up with/without insulation ? Data is given in the attached excel sheet.
Query:
I have considered Isopropanol as a liquid in the storage tank. My calculation gives around 38hrs to drop down temp from 45 to 30 deg C without insulation and around 102 hrs with 25 mm glass wool insulation [you can select the insulation thickness in the calculation]. I don't have the actual data which can guide me how much it should tanke. However, me and my seniors think it should not take such long time for temperature drop down.
Has someone come across similar problem or done the calculation using this article?. I am not here to challenge the article but feel there may be some mistake in my part. I would be happy is somebody validate this calculation.
Note: I have used the first iteration while the article has used number of iterations for more accuracy.
Thanks in advance.
Regards,
KR
[alert]To get the final version of the spreadsheet, visit our Hall of Fame Downloads. Do not use the attachments in this thread. The Download section contains the finalized version of the spreadsheet.[/alert]
Storage Tank Heat Loss Calculation Based On Kumana and Kothari Article
#1
Posted 28 September 2009  11:51 AM
#2
Posted 22 June 2010  05:13 PM
I saw your post and the spreadsheet. I would like to communicate with you regarding a somewhat different tank problem and would like to get your insights. I am new on the forum and am not familiar with the procedure. Would it be possible communicate via a direct email?
#3
Posted 02 August 2010  03:59 AM
I am no expert but I think there's a mistake in your calculation  when you calculate the Grashof number for the vapour at wall. You should have used the height of the vapour instead of the liquid.
#4
Posted 27 December 2010  05:35 PM
let you try this xlsheet for wet area calculation.
Hope this helps
Breizh
Attached Files
#5
Posted 27 December 2010  08:17 PM
#6
Posted 03 January 2011  02:31 AM
*Regarding the paper which supports the xcel sheet , I don't undestand why in equation 24 the temperature in Rankine degree is divided by 100 .
equivalent coefficient for radiative heat transfer (24)
hR = 0.1713*eps* (((Tws+460)/100)^4 ((Ta+460)/100)^4))/(TwsTA)
**Now in the xcel sheet equation 24 , there is a "mix up of unit " for the temperature , the Stefan boltzmann constant is expressed in BTU/h ft2 R4 and the temperatutre are in C in the spread sheet
Breizh
#7
Posted 03 January 2011  07:54 PM
Breizh:
Thx; This will be useful for calculation of the wetted area anyway. But unfortunately it doesn't answer my question.
equivalent diameter D = 4* Area concerned by heat transfer / wetted perimeter
#8
Posted 08 January 2011  12:01 PM
If you haven't done so, please replace the attachment with the equation correction in your original posts and add a notation as such. We don't want to keep attachments with known errors in the forums. Nice work on the spreadsheet!
Please find attached a revision of the spreadsheet as posted by KR originally. I tried to contact her directly; but as I didn't get any reply, I updated the spreadsheet myself.
Revision notes at Storage Tank Heat Loss Calcs  Rev.1 31.12.2010.xls:
1) Correction of calculation of the Grashof number of vapor phase to direct to the correct cell;
2) Note added that I suggest the use of the effective length or hydraulic diameter to the roof rather than the equivalent diameter (see engg. toolbox for difference between the two). However, I didn't change this.
3) Degrees Celsius (^{o}C) is replaced by K for a correct calculation in SI units. Note: It is very important to be consistent in using the proper units. K is the correct temperature unit for SI units and not ˚C. By doing this, a slight different outcome of the heat transfer and heat loss was obtained as compared to the original spreadsheet. This is basically due to an error in the calculation of the radiation heat loss with ˚C instead of K.
4) Recalculation of temperatures introduced, by manual iteration to obtain a more accurate values for the heat transfer coefficients.
5) The formula for cooling of the tank changed. In the original revision, a linear calculation was used; however, the heat loss is a logarithmic relation. In this example the total mass of six separate tanks was used to estimate the time of cooling from 40 ^{o}C to 35 ^{o}C. This has been changed to one tank, as the cooling of the sole tank is not influenced by the number of tanks. The original cooling time was too conservative for these reasons.
For those who are interested, please check this forum the coming weeks as I'm in the process of preparing a spreadsheet for heat loss of a partly filled horizontal tank/drum/vessel.
Attached Files
Edited by Art Montemayor, 05 February 2012  01:41 PM.
increased font for legibility
#9
Posted 10 January 2011  11:30 AM
Thank you very much for your positive and proactive response to the discovered discrepancy in the submitted workbook.
All submitted information, workbooks, and data are given in our Forums for the benefit of ALL members and what you have done is help us all to not only enjoy the combined talents of all, but also made the contributions stronger, accurate, and applicable as potential useful tools in our professional lives.
I wish all our members would take this into consideration.
#10
Posted 10 April 2011  11:33 PM
Sandeep
#11
Posted 11 April 2011  01:24 PM
Completely and fully agree with you Enrico. Also waiting for you next spreadsheet for partially filled vessels. Thank  with warm regards  Sandeep
See the "Hall of Fame" download session. It's there.
#12
Posted 26 July 2011  07:38 AM
I was using the spread sheet attached on this thread. However, there is only one thing which is not clear to me.
Concerning equation 23, how did it turn out to as:
H (ground) = 8 * k(ground) / (3.1416 * Diameter)
Currently I am calculating the heat loss of a storage tank for liquid sulphur. I am planning to use the spread sheet for the initial estimate of heat losses.
By the way, our tank has a concrete ring 200 mm in height. The empty space below the tank will be filled with soil/sand.
Thanks!
#13
Posted 27 July 2011  08:05 PM
I am also in the same difficult situation as you, with regards to predicting the number of hours to cool down a tank because the ambient conditions vary at different locations. We could have arrived at the number of hours to cool down from 45 to 30 deg. C  but what if suddenly there was a heavy rain, storm or snow which may drastically reduce the cooling down period?
I think somebody has to comment further if this could trigger a vacuum inside the tank which could result in a disastrous collapse.
If I may add, is the attached tank heat loss calcs spreadsheet also apply to doublewalled cryogenic tanks?
robjul
#14
Posted 13 August 2011  05:49 AM
The formula relates to the conduction of a semifinite solid. The reference is: W.Rohsenow, 1973, Handbook of Heat Transfer.
I think you could simplify the bottom by assuming that the heat loss through the ground is completely via the soil. There was an article (please check the forums), which I think is by Thyco Thermal, that also specifies typical heat transfer coefficients for concrete skirts etc.
I hope this helps.
Regards,
Enrico
#15
Posted 13 August 2011  05:56 AM
The impact of a rainstorm is significant indeed. If a vacuum occurs or not depends on the capacity of your breathing valve or blanketing system. Probably Standard API 2000 describes something about rainstorms. I don't think it's a straightforward calculation anyway, as it's a dynamic situation. Probably you can assume a thin layer of cold water on the roof and repeat the calcs.
The formulas are applicable for cryogenic double walled tanks; however, you should further modify the spreadsheet. You should consider the heat transfer from the medium to the inner side (vacuum or perlite filled?) and from the inside to the outside. Probabaly you'll find readytouse data on the internet or on this forum.
Hope this helps,
Regards,
Enrico
#16
Posted 26 October 2011  05:35 PM
#17
Posted 05 May 2012  10:24 AM
what about spherical tanks? such as an propylene tank...
#18
Posted 05 May 2012  12:25 PM
I think you are trying to find out information for your design of a saturated propylene spherical storage tank (to be found in another thread in our forums). That, in my opinion, is another totally different subject. As Enrico has ably explained to you, the basic design and formulas are to be found in the modified spreadsheet found in our Forum downloads. It is your job to use that basis and modify to reflect the conditions that you are imposing on your spherical tank.
Your spherical tank is a simple application from a process design pointofview. It deals with saturated, pure propylene. Therefore, the operating pressure inside the tank is equivalent to the corresponding vapor pressure of the propylene at the ambient temperature found outside the tank  assuming the tank is not insulated. But we don't know that  do we? You haven't furnished all of the basic data; you've just stated a general question.
You should be able to use the given spreadsheet and modify it to suit your basic conditions and scope of work.
#19
Posted 05 May 2012  08:28 PM
Many Thanks,
i attached my tank data sheet.
i want to know what kind of insulation shall be specified for this tank & how can i calculate its insulation ??
my basically question is about spreadsheet.
here we have some spreadsheet for download;
for fonds bombes surface mouillee, for vertical, for horizontal & for pipe heat losses calculation.
i want to know which one is useful for my spherical tank??
i should start with which one?
i cant attach any things,
operation temp.= 40 c
operation pressure= 2.34 barg
capacity=7400 m3
fluid=propene
hyper
Edited by Hyper, 05 May 2012  09:34 PM.
#20
Posted 17 May 2012  08:08 AM
Does anyone have a similar spreadsheet for the calculations for a vertical tank that is located outside?
Thank you in advance for the help.
Brent
#21
Posted 17 May 2012  01:22 PM
Have your read this thread?
The main topic of this thread has been a vertical, outside, atmospheric storage tank. And that is the basis for the spread sheet developed by Enrico. Isn't that what you are after?
#22
Posted 01 July 2012  01:26 AM
I doubt that the spreadshet is applicable to cryogenic tanks. The heat transfer / leak from these tanks is so complexl that there is no real way to calculate it with a spreadsheet. Only FEM / CFD software can do it very precisely. The cryogenic tanks heat leak are "qualified" with a test. See Iso standard ISO 21014 or EN 21213.
#23
Posted 02 July 2012  12:12 PM
Dear breizhonek; the article and the spreadsheet completmente applies to refrigerated tanks, you have detailed or investigated each of the equations or made minor changes to suit your system?
I have done calculations the refrigerated tank using Kumana article and making the necessary changes to in the spreadsheet. Between the points to Look is the Rayleigh number for the refrigerated tanks regime is turbulent heat transfer to the top and bottom, you can get from http://www.cheresour...ion/topic/15473 rayleighnumber /
You must also change the heat transfer area, equivalent diameter of the bottom and top of the tank and check the consistency between units of measurement, change the properties of air as in the spreadsheet area is occupied by dry air.
I think this is the most important thing to keep in mind. Good luck.
#24
Posted 06 February 2013  05:16 AM
Hi all,
I'm looking to calculate of the wind enhancement factor (or outside air heat transfer coefficient directly) rather than using the figure. However, I'm stuggling to find any reliable source that provides this.
Unfortunatly I don't have access to the Stuhlbarg article referenced in the Kumana Kothari article.
Can anyone help me with this?
Thanks in advance!
#25
Posted 06 February 2013  07:16 AM
1. Concerning the "wind enhancement factor", <http://www.cheresour...ninsulatedpipe> post no 23 by Breizh might be helpful. It includes curves to show wind effect on heat loss (not an algebraic formula).
2. Propylene sphere mentioned by Hyper must be semi refrigerated, as indicated by given data (operating temp=40 oC, press=+2.34 barg). This may be development of <http://www.cheresour...sphericaltanks>. Basic design for smaller local propylene spheres (fully pressurized  no refrigeration, 1979) did not specify insulation, semi refrigerated sphere shall require insulation.
3. Sincere thanks to Enrico Lammers for the usefull "Storage Tank Heat Loss Calcs  Rev.1 31.12.2010.xls" on the tank heat loss.
Edited by kkala, 06 February 2013  07:21 AM.
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