5 replies to this topic

[lafondejs]

Dear All,

 

I need to design an air heater to heat up air from 27C to 160C. (Air flow rate is 3500 kg/h & pressure 0.5barg). And two options have been asked.

1. Using Steam – I will be able to design without any problem.

1. Using Electric heating coil – I have no idea how do the thermal design. I can simply calculate the heat balance, but I have no idea about how to arrange the electric coils (heating coil pattern and pitch ??) and also I have no idea about heat loss??

(Air side pressure drop < 0.05bar)

 

Can somebody guide me please?

 

Thanks.

 

[thorium90]

When I read your question I thought of a hair dryer...

 

A quick search off google reveals a useful paper

 

http://www.carnes.co...df/B233-234.pdf

Edited by thorium90, 10 February 2013 - 08:57 AM.

[lafondejs]

When I read your question I thought of a hair dryer...

 

A quick search off google reveals a useful paper

 

http://www.carnes.co...df/B233-234.pdf

Thanks thorium90,..

[Steve Hall]

For an electric heater you would purchase a standard unit, such as from Chromalox, www.chromalox.com. Let the vendor do the engineering.

[Art Montemayor]

lafondejs:

 

Steve Hall is giving you the correct advice.  What he prescribes is the smartest thing to do.

 

I've designed and built gas electric heaters - all with Chromalox elements.  That was some time ago when I was running gas plants in South America.  I learned how to do it from a Chromalox technician.  But I wouldn't do it anymore.  It is far more practical and secure when you rely on Chromalox to do the hard, dirty work or sizing and selecting the correct electrical elements.

 

You are wise in asking for advice before proceeding on your own.  The watt density required for each application is just one of the difficulties in selecting the correct element.  Chromalox can answer all your questions on the application and offer useful advice for a safe and dependable installation.  But you must be specific and furnish all the required basic data to them.

 

Good luck.

[lafondejs]

For an electric heater you would purchase a standard unit, such as from Chromalox, www.chromalox.com. Let the vendor do the engineering.

Thanks