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Office/Computer Wall Cabinet

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Project by slooper posted 11-22-2008 07:07 AM 12577 views 0 times favorited 7 comments Add to Favorites Watch

This is a good challenge for you engineering types.

I put an 8’x8’ office in the corner of my workshop, really no bigger than a cubicle. Most people call it a closet, but the audience here understands that the workshop takes priority when it comes to space, even if I am a computer programmer by profession and need sufficient space for all my computer equipment, office storage and, of course, a desk. Hence the need for a really compact, functional and efficient computer wall cabinet which involves a bit of ingenuity.

The cabinet is incomplete, so here’s a sketchup diagram of the original design.

Cabinet Design

There are three components of this cabinet that posed real challenges. I’ll mention the first two for interest and focus primarily on the last as that’s where I need the most help.

Torsion Box Base
First, this wall cabinet and its contents supply a bit of heft and the cabinet has no place for legs to support it. So for the base I chose a torsion box for its strength. I jointed and planed 2×4s and sandwiched them between 3/4” and 1/2” plywood. It seems pretty rock-solid to me. You can see the amount of stuff already in it.
Wall Cabinet Heft

Rear Computer Access and Cord Management
Second, being that it will house a lot of computer equipment (4 computers, routers, modem printer, CD duplicator and battery backup), access to the back of the computers required full-extension slides and some organized way of taming all those cords. My rather crude approach here was to use a combination of electrical cable staples and Velcro cord straps strategically places to keep the cord movement away from catching on corners and getting trapped between drawer and cabinet. Think of how those printer carriage flat cables work. That’s what I was shooting for. (I’m open to better ideas if you have any.)

Full Extention Drawers for Rear Access

Airflow and Emissions
Third, and this is the most challenging, airflow must pass by the computer equipment within the cabinet to both cool them off and to send the exhaust, with it’s toxic metal emissions, out of the room entirely. In other words, a fan must blow that the bad air outside, new air must come into the room, and the path of the airflow must be drawn through the inside of the cabinet and over the computers in such a way to prevent the emissions from escaping into my small room. Think of a fire place, all the smoke must go up and outside not down. It is critical, not only to limit, but to eliminate the possibility of my breathing the toxic emissions as I got seriously ill because of them last winter when I did not give the room sufficient ventilation. Simply getting air through the cabinets wasn’t the challenge, though. It was getting airflow through two separate cases, or sections of the cabinet equally, or at least that stale air does not reside in either.

Interestingly, my problem solving skills from my computer programming background came into play. I’m presenting my solution before I do the work in hopes some of you may have better ideas.

Specifications
  • I have a 50 cfm bathroom fan with 6” ducting (for quietness) directly above the cabinet.
  • I have two 4” through-the-wall ventilators (with electro-static filters) for replacement air
Requirements
  • Air must flow equally through two, side-by-side cases, drawn out by a single fan.
  • If possible, NO air at all should seep into the room.

The challenge has two parts: 1) control quantity of air through each case (to avoid path-of-least-resistance problem) and 2) control the flow path through the cabinets (draw air in front of as well as behind computer equipment to “capture” all emissions.

My Solution

Forcing the air through the cabinet
Obviously I need to encase the fan above the cabinet so that air MUST pass through the cabinet, otherwise the path of least resistance will be to just draw the air directly from the room. So step one, build an enclosure for that space between the cabinet and fan.

Regulating the quantity of air in each cabinet:
Since there is only one fan for two cabinets, it’d be difficult to calculate the size holes I need in each to control the quantity of air coming through each. So, instead, I looked to the ventilators for my answer. The key is that the number of ventilators equals the number of cases through which I need to draw the air: TWO. If the most air possible coming into the room is through two 4” holes, then restricting each cabinet’s maximum airflow by a 4” hole above the case and just below the encased fan would serve as a regulator. I just need to make sure at least that amount of air can flow through the bottom. So at the base of each case I put in a mobile-home style floor vent (4”x8”). These vents also conveniently allow me to adjust the airflow in each cabinet as needed.

Regulators

Controlling Airflow Path
The back of the computers is where the heavy metals are emitted, so directing the air past this area is a must. But while having the air flow by the back of the computers would take the majority of emissions with it, having air flow past the front of the cabinet will prevent some of it from seeping into the room and into my lungs. In fact, it’d be ideal if I get a front-to-back and out airflow in each compartment. But since that’s not possible, at least not with my cabinet design, the closer I get to that the better off I’ll be. So above my “floor vent” and below my “regulator” hole, I’ll put peg boards, adding some bigger holes towards the front and back to help the air along the desired path.

I’m not sure how perfect this system will be, but it seems to be working in my mind. If any of you can think of a reason my plan will or won’t work, or if you have a better solution, I’m all ears.

Thanks,
Slooper





7 comments so far

View Bureaucrat's profile

Bureaucrat

18340 posts in 4713 days


#1 posted 11-22-2008 08:58 AM

Though certainly not elegant my solution would be: 1: remove the cases from the pcs, 2. make the base as holey as possible, hardware cloth wold do. 3. put filters under the base, 4. enclose the front and 5. hook hose from the top of the unit up to the exhaust fan. Not having any training in aerodynamics I have no idea that the physics of this works, it just seems like it should. Also if you have to get to the pcs a lot, effectiveness would drop.

-- Gary D.

View Rustic's profile

Rustic

3257 posts in 4657 days


#2 posted 11-22-2008 05:45 PM

I would think that you would want to enclose the front to keep the sawdust from clogging the computer components. As a Computer Support Technician, that would be my reccomendation. For air flow I would put “vent holes” with filters on the top and bottom. Just my 2 cents worth. Other than that I love the design and craftsmanship. So in a sense I agree with Bureaucrat.

-- www.carvingandturningsbyrick.com, Rick Kruse, Grand Rapids, MI

View slooper's profile

slooper

37 posts in 4540 days


#3 posted 11-22-2008 05:49 PM

Gary,

Thanks for the input.

I’m not sure why I forgot to mention this, but I plan on putting smoked glass doors on the front of the two computer sections (your #4) and leave a small gap for air to flow through.

As for hooking up hoses (#5), there just simply isn’t enough room (<3>d be to open-air static electricity, particularly if I heat the room which tends to dry it out.

Thanks again for taking the time to think this through. :)
-Slooper

View slooper's profile

slooper

37 posts in 4540 days


#4 posted 11-22-2008 05:55 PM

Rick,

I think I misled readers when I used the term “cubicle.” I only meant that in size. My office and shop are actually separate rooms with an airtight wall between them and a separate entrance, so as to be free from any sawdust as well as keeping the finishing odors from my office space. Fortunately for me, someone with your wisdom got to me before I finished the inside of my building. :)

Thanks,
-Slooper

View Dragonsrite's profile

Dragonsrite

136 posts in 4458 days


#5 posted 02-07-2009 11:57 PM

Slooper,

Would you please be so kind as to point me in the proper direction to learn more about the heavy metal emissions of computers. A google search only brought up info on contaminated soil issues; nothing about air quality during the useful life of a system.

-- Dragonsrite, Minnesota

View slooper's profile

slooper

37 posts in 4540 days


#6 posted 02-08-2009 12:46 AM

Dragonsrite,

You might try “Computer Toxicity”.

Here’s a site that lists some toxic materials used in computers including lead, beryllium, mercury and arsenic. Keep in mind that the fan constantly blows air over these components to cool them and blows the contaminated air into the room. With inadequate ventilation, it can accumulate in the room and reach dangerous levels quickly, which is what happened to me. Hence the reason for this complicated contraption.

http://www.canz.org.nz/Computer%20toxicity.htm

Good health to ya,
-Slooper

View Dragonsrite's profile

Dragonsrite

136 posts in 4458 days


#7 posted 02-08-2009 01:30 AM

Thank You, I’ll check it out.

-- Dragonsrite, Minnesota

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