The window unit took my attention today. It seems that the 9V battery works but gets very hot, very quickly. I also noticed that I had a cooler breeze inside the bus when the cooler outside air was blowing in through the open window.
Thinking about the cool air coming in through the window and combining that with a different form of ventilation makes more sense. Clearly I need to pump cool air in rather than hot air out. I had hoped my rear ventilation setup would have done everything I wanted. I was wrong there. It does serve a purpose though. I'm sure air flows in that direction now.
The new idea is a return to an old idea - to install a fan or fans to pump cooler air into the bus. I could put together a simple screen to pop into a window. That's not hard. I'd rather be able to pump cool air in though. I need to be able to filter the junk out of it.
Looking at the bus, I noticed a couple of panels under the driver's window that seem to be screwed rather than riveted. It's part of the heater assembly and has me wondering whether I could plumb into the air intake there and blow cool air from outside in through that intake.
Deciding not to attend the photo club on account of it being too little time to wind down and sleep though I've had less sleep when I was working retail, I set to work on the removable panel. Several screws proved resistant until hut several times with a hammer. One screw sheared when unscrewing and one head stripped. Needless to say, the Grabbit didn't work. I keep trying that thing and it never ever works. So, I resorted to my trusty angle grinder.
Investigating the vent on the side of the bus with the defroster fan on, there was no air movement. That was baffling. Clearly that vent is for something different. It is obvious therefore from today's investigations that I need to install an inlet vent. I'm tending toward installing my inlet at the front either behind the driver's seat or in the fridge compartment. I could install under the desk in the galley too though that'd be above the fuel tank which I don't feel is a good place, not to mention the problem of putting electricity in that side of the bus.
After I put the cover back, I returned to my window vent. This time, I put the battery holder from one of my $5 fans to power both fans. That wasn't too tricky. The problem came when the installed window unit kept falling inwards out of the window. With the battery pack and fans, it's now back heavy. I'll have to think on that. Meanwhile, with the fans set to suck, the temperature in the galley quickly dropped two degrees from 95 to 93, pretty closely matching the bedroom temperature of 92.4.
As can be seen, I propped the unit up with a stick. The cool breeze was very welcome! I'm giving more thought to installing inlet vents like my outlet vents but at the front of the bus. Given plenty insulation squirted in and removable vent covers, that could well be the answer. The alternative is a turbo vent behind the driver's seat - which would probably be a load easier.
That's pretty much all I did today. With a reverse switch and the falling problem fixed, that could become a useful cooking extraction fan. Truth be told, a roof vent would be better for many things but it's so tricky to install what with body ribs etc not to mention the problem of sealing it adequately.