wth isthis good for?

[ivymike]

I have a concept heat exchanger design for water-to-water or air-to-water which varies thermal resistamce to set outlet temperature of one of the fluids, using no moving parts and without changing flow on either side of the hx. It costs too much to be used in the application for which I originally conceived it...anyone know of a place where such a unit would be useful?

 

[zdas04]

Would it work on oil/glycol? I'm thinking of an oil-flooded screw, if you control the temperature out of the screw (into the HX) in a very narrow band then the screw becomes a trouble free bit of kit. Flow out of the HX goes to an oil pump then splits off to bearing lubrication and injection oil. The oil out of the compression loop goes into a coalescing filter and then to the HX (lube oil is also dumped into the filter). I need the process to look at the temperature immediately out of the screw and maintain that constant. Temperature at that point is a function of (1) oil inlet temp; (2) gas inlet temp; (3) oil flow rate; (4) gas flow rate; and (5) compression ratios. All of which change moment to moment.

The most effective installation I've done is to flow the oil into a plate and frame HX with the glycol side sent to a fin-fan cooler. The control scheme is:
[ul]
[li]Vary the glycol pump within its design range (on the low side if you get to minimum flow it can turn off)[/li]
[li]Vary the oil pump speed within its design range (it can't turn off) [/li]
[/ul]

With this scheme I was able to maintain temperature out of the screw at +/- 0.5F, winter to summer, minimum gas flow to maximum gas flow, but it is expensive. Can your concept heat exchanger do this (and allow gravity flow of the glycol) which could eliminate the glycol pump and VFD, and possibly the oil pump VFD)?

David Simpson, PE
MuleShoe Engineering

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The plural of anecdote is not "data"

 

[KENAT]

Geothermal energy applications? Maybe not power generation but geothermal heating?

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[ivymike]

0.5F sounds ridiculously tight...but I can't rule it out offhand. The gravity flow however suggests a time delay bedore flow starts in earnest when heat load goes up...that worries me a bit. I will hve to see about whether I can round up any analysis support for a side project.