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Cooling "Outside the Box"
Background: I was forced to build a pseudo 19" rack enclosure for some of my boxen.
The enclosure houses two wide body mid-towers, most of my networking hardware, a flatbed scanner, printer and has space below for two full towers. This is all crammed into a box 19 inches wide, 24 inches deep and 52 inches tall. Even without the two full towers installed there is enough waste heat generated to cause concern.
However, the enclosure was built with internal airflow in mind: The rear of the case was cased and had a provision for 1/4" thick MDF backpanels to seal the rear of the enlosure off. Likewise, the networking shelf had a slotted cover made for the front to allow cool air in. at the rear of each shelf in the case was a trio of 3 5/8" holes drilled in them to allow for upward airflow. The Scanner drawer and the printer shelf were isolated from the rear of the case by internal bulkheads which had holes drilled in them to allow for cable routing.
At the tops of the case, two 4 3/4" diameter holes were drilled and a Sunon120MM 5 Blade Fans was mounted overtop each of the holes.
These fans run at ~2500 RPM and are annoyingly loud (44dB or so at full yawn), so I added an Enermax 6 Fan baybus controller to tame the RPMs down to much more reasonable audial levels - 1600 RPM was the lowest RPM I could adjust the Fans to and still have them reliably start from a standstill.
The bezels on each of the mid towers were modified slightly to allow more air to flow into the frontt: this consisted of daylighting out all of the decorative front case holes in the plastic with a 1/8" drill bit.
The Two (Mid) Towers run 24x7: One is the Smoothwall box: It generates very little waste heat because it's processor is one of the underutilized Pentium IIIs on the planet: the motherboard is running a fair number of cards, but there isn't much happening there either (An unused SIS-based AGP VGA Adapter, a trio of PCI NICs and an ISA modem) under full load the board can pull about 125watts - this machine has yet to run at more than 10% of full load.
It's partner to the right is another matter entirely.
This machine is an Extended ATX Tyan Thunderbolt running a pair of PIII Katmai 600MHz Processors, ets...see the bottom of my Signature for all the gory details.
This case had a total of six fans running in it in a vain attempt to keep temperatures under control. With the side covers on, this dual P3 system will go to over 55 degrees C in about an hour assuming an ambient temperature of 23-25 degrees C.
Fearing the worst, I placed the Duallie and the Smoothwall Box in the top of the enclosure and fired up them up....after 30 minutes temperature monitors inside the cases rose from an ambient temperature of 23 degrees C and stabilized at 27 degrees C...with the HDDs running from 30 to 34 Degrees C.
I was flabbergasted! The 120MM case fans drew off all wasteheat from both machines with ease! The only way I can account for such a dramatic increase in cooling performance is that the cases are essentially sitting in a tunnel: the only way for cool air to enter is from the front: the only path out of the tunnel are the two 120MM exhaust fans. This scheme assures all warm air being drawn off in short order, with capacity to spare.
The enclosure houses two wide body mid-towers, most of my networking hardware, a flatbed scanner, printer and has space below for two full towers. This is all crammed into a box 19 inches wide, 24 inches deep and 52 inches tall. Even without the two full towers installed there is enough waste heat generated to cause concern.
However, the enclosure was built with internal airflow in mind: The rear of the case was cased and had a provision for 1/4" thick MDF backpanels to seal the rear of the enlosure off. Likewise, the networking shelf had a slotted cover made for the front to allow cool air in. at the rear of each shelf in the case was a trio of 3 5/8" holes drilled in them to allow for upward airflow. The Scanner drawer and the printer shelf were isolated from the rear of the case by internal bulkheads which had holes drilled in them to allow for cable routing.
At the tops of the case, two 4 3/4" diameter holes were drilled and a Sunon120MM 5 Blade Fans was mounted overtop each of the holes.
These fans run at ~2500 RPM and are annoyingly loud (44dB or so at full yawn), so I added an Enermax 6 Fan baybus controller to tame the RPMs down to much more reasonable audial levels - 1600 RPM was the lowest RPM I could adjust the Fans to and still have them reliably start from a standstill.
The bezels on each of the mid towers were modified slightly to allow more air to flow into the frontt: this consisted of daylighting out all of the decorative front case holes in the plastic with a 1/8" drill bit.
The Two (Mid) Towers run 24x7: One is the Smoothwall box: It generates very little waste heat because it's processor is one of the underutilized Pentium IIIs on the planet: the motherboard is running a fair number of cards, but there isn't much happening there either (An unused SIS-based AGP VGA Adapter, a trio of PCI NICs and an ISA modem) under full load the board can pull about 125watts - this machine has yet to run at more than 10% of full load.
It's partner to the right is another matter entirely.
This machine is an Extended ATX Tyan Thunderbolt running a pair of PIII Katmai 600MHz Processors, ets...see the bottom of my Signature for all the gory details.
This case had a total of six fans running in it in a vain attempt to keep temperatures under control. With the side covers on, this dual P3 system will go to over 55 degrees C in about an hour assuming an ambient temperature of 23-25 degrees C.
Fearing the worst, I placed the Duallie and the Smoothwall Box in the top of the enclosure and fired up them up....after 30 minutes temperature monitors inside the cases rose from an ambient temperature of 23 degrees C and stabilized at 27 degrees C...with the HDDs running from 30 to 34 Degrees C.
I was flabbergasted! The 120MM case fans drew off all wasteheat from both machines with ease! The only way I can account for such a dramatic increase in cooling performance is that the cases are essentially sitting in a tunnel: the only way for cool air to enter is from the front: the only path out of the tunnel are the two 120MM exhaust fans. This scheme assures all warm air being drawn off in short order, with capacity to spare.