It is pretty close to the same as my mock up, except I didn't end up sloping in the sides toward the front of the AC and just made them 90 degree box shaped. I bent all of the aluminum on a $50 harbor freight bender.
I taped strips of paper in various places on the vent to watch the airflow and it does blow and suck in the correct areas as it should. I put some fiberglass screen on the inside of the outside vent grill to keep bugs/spiders out. This does not seem to impede the airflow. I attached the screen with dobs of JB weld. Dobs might not be a word since it is underlined in red. Am I babbling yet? I purchased the outside vent grill at either Lowes or Home Depot. If I had pants on I would go outside and measure it. Your dimensions sound right...you just want the vent to be large enough side to side to allow air to flow in both sides so it can be blown out the front.
Here is a picture from the inside without the vent cover on to give you an idea of the ducting. Note that before I added the cover I taped the seams of the shroud with a rubber type tape (like eternabond or something?) so if water blows in from the outside it will just collect in the pan. Oh yes, the bottom of the shroud is made up of an aluminum pan I bent up and sealed the corners with JB weld to make a water catch if the AC's condensation overflows. I have a sponge in each side to absorb the water and wick it up into the air where the ducting action will cause it to evaporate and assist in cooling the unit. Did that make any sense? So far I have not seen the water overflow the actual Danby pan, even in the humid NW.
I taped strips of paper in various places on the vent to watch the airflow and it does blow and suck in the correct areas as it should. I put some fiberglass screen on the inside of the outside vent grill to keep bugs/spiders out. This does not seem to impede the airflow. I attached the screen with dobs of JB weld. Dobs might not be a word since it is underlined in red. Am I babbling yet? I purchased the outside vent grill at either Lowes or Home Depot. If I had pants on I would go outside and measure it. Your dimensions sound right...you just want the vent to be large enough side to side to allow air to flow in both sides so it can be blown out the front.
Here is a picture from the inside without the vent cover on to give you an idea of the ducting. Note that before I added the cover I taped the seams of the shroud with a rubber type tape (like eternabond or something?) so if water blows in from the outside it will just collect in the pan. Oh yes, the bottom of the shroud is made up of an aluminum pan I bent up and sealed the corners with JB weld to make a water catch if the AC's condensation overflows. I have a sponge in each side to absorb the water and wick it up into the air where the ducting action will cause it to evaporate and assist in cooling the unit. Did that make any sense? So far I have not seen the water overflow the actual Danby pan, even in the humid NW.
Just an update on this little AC unit thread from last year. I built a shroud out of aluminum that directs the outside air into the side vents and blows the exhaust air outside. This allows the AC unit to be fully mounted inside on the side of the camper. On the hottest day we have had so far (90 degrees) it easily cooled the camper down to 67 degrees. I lined the outside of the aluminum shroud with 1 inch of polyisocyanurate rigid foam insulation. Eventually I will make a nice finished wood cabinet on the inside to cover the housing and just leave the front of the AC exposed.
Ok so through wall usually means the air conditioner has been designed to pull in air through the back of the AC and vent the air out of the same back. With our ducting, we are just doing the same thing. Here is a diagram of the airflow in the mockup I did which seems to work pretty well (tested with paper streamers to map the vector field of air flow). Obviously blue represents incoming air and red is the exhaust air that has passed through the condenser.
edit: the top two vent louvers on the external grill I used are also above the level of the Danby AC so some air can flow in there and across the top of the AC then down into the unit. The AC is 12 inches tall and the grill is 14 x 25.
edit: the top two vent louvers on the external grill I used are also above the level of the Danby AC so some air can flow in there and across the top of the AC then down into the unit. The AC is 12 inches tall and the grill is 14 x 25.
