Roughly Calculating thermal losses

[Ryan DelaCourt]

Hi all,

Im currently woring on an improved heat exchanger which essentially is a block of t6 aluminium with an array of vertical Quartz tubes passing through (Block essentially has clearance holes which tubing pass through). fluid enters a fluid manifold at the bottom, travels upward and exits on the top of the assembly thorugh a mirrored fluid manifold.

Block is heated by cartridge heaters.

In theory I roughly have around 3.8 times more tubing surface area contact than existing design, so in theory it should out-perform our current design by quite a bit.

However I want to get a feel for thermal losses, currently there is no blanket or shoud around the heat exchanger so obviuously it is goign to be emitting a substantial amount of heat.

I do plan on introducing a blanket of some sort, but for the moment, i would like to get a rough idea of what thermal losses i should expect.

Can anyone help point me in the right direction ?

Thank you

R

 

[rb1957]

You're trying to heat (or cool) something. Why not measure it's temperature pre- and post- heat exchanger ? "all" you care about is the useful heat transfer, what does it matter is heat is being lost somewhere (unless you're trying to heat something) ?

another day in paradise, or is paradise one day closer ?

 

[BrianE22]

So this is just a block of aluminum in free air? For steady state, you would just need to calculate the convective heat transfer. Problem is getting an accurate heat transfer coefficient.

 

[LittleInch]

1) this should be in the heat transfer and thermodynamics forum (have you looked in there for answers)
2) for anyone to help you you need to provide some drawings / sketch / dimensions and some data on temperature, heat input / electrical input, flow rate, mass of the block etc.
3) when you out perform what do you mean? Heat transfer? heat output?, efficiency? What has changed form the original design? If you don't change the number of cartridges
4) Is heat loss convection? conduction? forced air? still air?

It all makes a big difference.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GregLocock]

Look in an old school thermo book, it'll have methods for working out your problem. Both of mine are elsewhere. You need one that talks about design of boilers and so on.

Cheers

Greg Locock


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[GregLocock]

This looks like a place to start

https://www.engr.colostate.edu/~allan/heat_trans/page4/page4.html

Cheers

Greg Locock


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[IRstuff]

How do the quartz tubes contact the block? An air gap would make the thermal losses moot.

TTFN (ta ta for now)
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