Does anybody have a good heat and power calculator for inside control cabinets, and what is the basis for assuming heat dissipation in say a PC with a 300W power supply?

 

http://www.sarel.fr/logiciels/clima/clima_31.exe

 

I have used the calculators or equations provided by the enclosure manufacturer. You should check with what they have first.

For a PC, 100% of the power consumed is converted to heat. How much power it consumes depends upon what hardware you have in the PC and could easily vary by a factor of 10, depending upon what you have installed.

The CPU, hard drive, graphics card, monitor, and power supply (efficiency losses) are the main power consumers. You can get power consumption figures for each of these from the respective manufacturers.

Alternatively, you can simply assume full rated power (e.g. 300W for the computer, plus the monitor consumption). This is good to use if you want a conservative estimate, and often the difference between full rated power and actual consumption may be too small to make any difference when sizing the cooling hardware.

 

I always add up the total wattage of all the heat producing elements in a panel. Power supplies are rarely loaded 100%, and not all devices are energized all the time, so this gives me a bit of a cushion in determining cooling requirements.

I usually oversize fans if required by 50% or so and put them on a thermostat so they only run as needed.

 

Try the Hoffmann catalog for a starter.

 

Responding to Garry Lonsdale's Jul 14 request for a calculator:

I use a "nomogram/graph for dummies" by Robert D'Aostino of Loral Electronics. It establishes the relationship between the three variables... heat, temp-rise, and enclosure surface area.

If any of you would like a copy, contact me.

Caveat:
It was constructed some 40 years ago. Nevertheless its accuracy is adequate for most technocrats!

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])

 

Although it isn't directly applicable to your question I've found Rod Elliot's writeup on audio amplifier heat sink design and application very useful http://sound.westhost.com/heatsinks.htm

Supercool (manufacturers of TEC-based cooling units) has a page featuring calculations
http://www.supercool.se/pages/calculate.html as does Marlow
http://www.marlow.com/TechnicalInfo/estimating_heat_loads.htm

Enclosure Manufacturer Software

Rittal http://www.rittal.com/com/service/Software/index.html
Hoffman http://www.hoffmanonline.com/Technical_Info/DownLoadTherSoft.htm

Electronics Cooling magazine has a lot of interesting articles on thermal management.
http://www.electronics-cooling.com/html/articles.html

I've used a simple Palm PDA application that gives decent results called "Epnltrz" by Soft-Toolz, but they appear to be defunct.

 

Dear friend,

I'm refering to the below attached link. I'll be interested to get the same copy. Would it be possible for you to forward me on mail address - [email protected]

Shailen Bhatt