1 or 2 heat exchangers
1 or 2 heat exchangers
(OP)
Hi,
I'm dealing with a project, where it was designed a heat transfer system between the boiler circuit and the process water, that has 2 heat exchangers instead of just 1. Of course that it has a simple circuit with a pump, to connect both heat exchangers.
I have searched in Holman and found an example that made the economic analisys between both options. In that case, it was better to have just 1 heat axchanger.
Can anyone give me the opinion about this? I would like to know better the reasons behind this option and why in some applications they are used.
Thanks!
I'm dealing with a project, where it was designed a heat transfer system between the boiler circuit and the process water, that has 2 heat exchangers instead of just 1. Of course that it has a simple circuit with a pump, to connect both heat exchangers.
I have searched in Holman and found an example that made the economic analisys between both options. In that case, it was better to have just 1 heat axchanger.
Can anyone give me the opinion about this? I would like to know better the reasons behind this option and why in some applications they are used.
Thanks!





RE: 1 or 2 heat exchangers
Good luck,
Latexman
RE: 1 or 2 heat exchangers
Two exchangers in parallel could be specified either because a single exchanger was too large for the plant's preferences or to allow one unit to be taken off-line for cleaning/repair while the plant continued at partial rates.
Typically two exchangers providing the same total surface area are more expensive than a single exchanger though that might not be true for all applications with exotic metallurgy, design conditions? I don't know, I don't have the data to say yes or no, just throwing it out as a possibility.
RE: 1 or 2 heat exchangers
thanks for the reply.
I think it might be correct. Maybe the if it was selected just 1 HX, probably it would be too bigger or something...
I attached a simple scheme of the parallel installation.
Thanks
RE: 1 or 2 heat exchangers
TD2K has clearly expressed the possible temperature "crossover" reason for a series arrangement. Besides, generally, smaller units in series are more efficient, i.e., need less total surface area that one larger unit for the same duties.
RE: 1 or 2 heat exchangers
Thanks for the reply.
25362,
I understood your point, but can you take a look at the file that i've attached to see this particular case?
Thanks
RE: 1 or 2 heat exchangers
I've looked at the sketch. J.P.Holman's Heat Transfer 4th Ed., brings the relevant considerations in point 10-8.
RE: 1 or 2 heat exchangers
As i said before, i've taken a look in Holman. Maybe that's the same example... I will see closely and after i will reply again commenting what i've learned.