Evaporative cooling question

[Anonymous]

Posted by: Dave (old forum transfer)
Posted - 05/31/2002 : 04:05:16

We live in Phoenix and I have decided to air condition my 20x20 foot garage with an evaporative cooler. The manufactuer states that I need one 12x12 unrestricted exhaust opening for every 500 cubic feet/minute of airflow. For the unit that I bought, that amounts to about two 2x4 openings. My supply vents and relief vents are both going to be in the ceiling. I'm worried about the efficiency of the unit and having some of the cold air immediately sucked out the exhaust vents before it has had a chance to cool the air inthe garage. Any thoughts? The only thing that I can think of is simply to seperate the supply and exhaust vents as far as possible from each other. Any better ideas out there?

[Anonymous]

Posted by: Wgoodrich
Posted - 05/31/2002 : 14:41:10

In my opinion both the incoming ducts and the exhaust ducts both being in the ceiling will work. The farther away from each other the incoming and the exhaust is from each other the more effecient the cooling system will be. The more are flow through the room the more capable it will be to cool. However the more volume in and out of that area and the closer the incoming to the exhaust the more cooling loss will be experienced.

If you can I would install the incoming in more numerous in number and smaller in inlet size and placed nearest the floor as possible. You should have your design of incoming placed so that the incoming vents can block heat induction through doors and window cracks and to block convection heat through the glass of those windows. Heat filming the windows will also help to limit heat influx from the sun rays if glass is facing the sun.

Remember the more dispersed the cool air coming in the more even the feel of cooling. The more heat influx that can be countered by a planned placing of cooling ducts the better the feel of the cooling.

Remember that heat rises. You goal should be for the cool are to come in low and rise as that cool air rises then is allowed to vent out the top of the area when that cool air is of no value left to provide cooling to that area.

If you can place you incoming as far away from the incoming splitting the difference if you have incoming placed around the room down low then the venting should be in the ceiling in the center of the room.

Just plan out your placement of ducting both cooling vents and exhausting vents.

Too much air flow in and out of that area is a waste of power usage but too little flow in and out of that area is insufficient design of cooling. Middle of the road with good planning with the above in mind is your best results concerning comfort.

Hope this helps

Wg