
Principle of Conservation of Energy 49
3.17 The heat dissipating components of an electronic enclosure are cooled
by four fans that are mounted in front of the enclosure; two on the
left side and two on the right side. The air is drawn into the enclosure
through a 200 mm × 40 mm inlet in the back and pushed out of the
enclosure through two 80 mm × 40 mm exhausts in the front. The
total heat dissipation by the electronic components inside the enclo-
sure is 200 W. The air temperature and pressure at inlet are 55°C and
70 kPa. The maximum allowable exhaust air temperature is 70°C and
the air pressure at exhaust is also 70 kPa.
a. ...