10 replies to this topic

[damaraju chaitanya]

dear all,

can you please provide any spread sheet for calculation of over all heat transfer coefficient?

did any one work for it?

 

Thanks & Regards

D.Chaitanya

[mansari]

It is simple. You can develop your own spreadsheet. Overall Heat Transfer Coefficient "U" is calculated using the following equation

 

U = Q/(LMTD x A) where Q is the heat duty Btu/h (calculated from m x cp x dT), LMTD is the Log Mean Temperature Difference Deg F and A is the heat transfer area ft2 (available from the heat exchanger data sheet). This method is commonly used for routine monitoring of the Overall Heat Transfer Coefficient in the industry.

[Hrehaan]

What are the different correlations available for calculating the HTC? Can anyone plz give the link or list of them.

When Iam calculating heat recovery for one of the after coolers in air compressor system, the hot side and cold side heat recovery is not matching. Can anyone plz guide??

[srfish]

Hrehaan,

 

For heat transfer correlations, refer to any book with the title "Process Heat Transfer". I don't believe it is unusual to not match heat loads on air coolers. It is difficult to determine the outlet temperature on the air side. The wind varying in direction and intensity and the amount of clouds all effect this temperature.

[damaraju chaitanya]

dear manasari, thanks for your response.

i need over all heat transfer coefficient 'U' for calculating heat transfer area 'A' of heat exchanger. i know the formulae for 'U' but which needs a lot of stuff to calculate like inside & ouside heat transfer coefficients of shell side and as well fouling, thermal conductivities e.t.c.... i am looking for how generally the value of 'U' will be taken in industry level

 

Thanks

[mansari]

Dear Dchaitanya, as suggested by Srfish, please refer to any standard text book on heat transfer to find out the correlations and methodologies. One such book is Rules of Thumb for Chemical Engineer, here you can also find typical range of "U" for specific application as you were looking for

[breizh]

Google should assist you :

 http://www.google.fr...iw=1107&bih=592

 

Consider using the search engine in this forum !

Breizh

[damaraju chaitanya]

okay i will continue my search. i just thought to follow any workings done by our CHERESOURCES users

 

Thanq all

[khan83]

Dear ansari, 

would you like to suggest how to calculate the heat duty of two phase heat transfer.... because the equation you suggested it does not contain any correlation with latent heat ( as per your above comment  q=mcpdeltaT), it can only be applicable for single phase heat transfer. thanks

[curious_cat]

Dear ansari, 

would you like to suggest how to calculate the heat duty of two phase heat transfer.... because the equation you suggested it does not contain any correlation with latent heat ( as per your above comment  q=mcpdeltaT), it can only be applicable for single phase heat transfer. thanks

 

Q= mass flow rate (kg / sec) * Latent Heat of Vaporization (kJ/kg)

[chengineer]

Heat exchanger iOS application

https://itunes.apple...633422031?mt=8#!

I think it may be helpful to introduce an application (Heat Exchanger) which can be used in solving heat transfer equation and designing double pipe heat exchanger with following features:

1. Calculating each variable in energy balance equation
2. Designing double pipe heat exchanger with real size of pipe
3. Calculating overall heat transfer coefficient(U)
4. User can define any fluid with specific properties or select from most common fluids used in industrial application
5. Data can be edited in both SI and USCS unit standards.
6. User friendly UI design