Are there any technical spec about the released heat from hd7950 in kw or kjules?
I plan to put my 12hd7950 in duct system: fan -> air filter -> rig -> outside
Thanks
You can assume all electrical energy going into a computer is converted to heat. The TDP of a 7950 is 200 watts. It will be more if you overclock. It might be less...
http://en.wikipedia.org/wiki/Comparison_of_AMD_graphics_processing_unitshttp://en.wikipedia.org/wiki/Thermal_design_powerI'm sure some people here can tell you their own experience with how much a 7950 uses, most likely measured on the AC mains side of the PSU. So it will vary a bit with the efficiency of the PSU too.
200 watts = 0.2 kW = 0.2 kJ/s {since 1 watt is 1 J/s}