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Htri Warning-Excessive Latent Heat

excessive latent heat

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#1 nastaran

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Posted 22 April 2021 - 01:17 AM

Dear All,

 

There is a warning in HTRI for "air cooled condenser" as the following:

 

An excessive latent heat >2556 kj/kg (1100 BTU/lb) has been calculated for the hot fluid at isobar no.  1 around increment no.   7.  Using specific heats, the program calculates the incremental sensible vapor duty and the sensible liquid duty, and subtracts them from the total incremental duty.  The latent heat has been limited to 2556 kj/kg (1100 Btu/lb).  Check the specified heat release curve, liquid and vapor specific heat, and enthalpy values; rerun the case.."

 

 

I have checked the physical properties and they seems logical.would you please help me to understand the reason of this warning.The physical propertis has been attached

 

Thanks.

 

 

Attached Thumbnails

  • Capture6.JPG


#2 Pilesar

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Posted 22 April 2021 - 07:22 AM

between line 4 and line 6 of your data table, 973 kg/hr changes phase with duty of 0.81 MW. That calculates to a very high latent heat.



#3 IGC

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Posted 23 April 2021 - 02:14 AM

I've never used the "Total duty from the inlet", heat release curves before.  Weird.  

 

For the given flowrate there though and the corresponding duty changes, almost 0.05 weight fraction change for almost 0.5 MW of duty?  That seems very large for a heat exchanger, more along the lines of energy requirements to melt the unit.  


Edited by IGC, 23 April 2021 - 02:14 AM.


#4 nastaran

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Posted 26 April 2021 - 04:36 AM

between line 4 and line 6 of your data table, 973 kg/hr changes phase with duty of 0.81 MW. That calculates to a very high latent heat.

Thank you for your reply but I couldn't understand the reason of this warning.Do you mean that there is some thing wrong with the physical properties ?Would you please explain more?

Thanks a lot



#5 Pilesar

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Posted 26 April 2021 - 07:20 AM

Your data shows unusually high latent heat (higher than water) which results in a warning that you check your data.for errors. The HTRI program has a limit to the latent heat it will use in its calculations. I have found the HTRI customer support to be helpful and you may wish to contact them to see if you can force the calculations to use the data you supply. Your heat curve is unusual and may be beyond the modeling ability of the HTRI software.






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