cooling

FreeBrrd · August 2008

I building a little camper for my truck with a solar system for a few fans & lights. I've run into a few questions on cooling, insulation, etc. Can't find a good place to get answers. This seems like it might be ok place to ask. The forum has been so much help on solar stuff.

I'm planning on using one of the thin foil sound deadening, insulation (http://www.bondedlogic.com/insulator.htm). In the roof, I plan on having air flow through it. I'm not sure if the insulation should go above where the air flows thru or below. It's sort of like, if you had a house with air flow thru the attic, would you insulate the attic ceiling or the attic floor.

Does the air flow bring in the outside temperature or does the air movement cool the air?

Another question: Is it cooler to have a well insulated area closed to outside air or open to outside air? I prefer open, but cooler would outweigh.

The space I am dealing with is only about 4' x 7' x 4'. I plan on putting little awnings over the windows / fan inlets.

I can only afford a 64 Watt panel, battery, controller, etc. for now so only power 4 to 6 computer style fans and a couple of lights. I plan on adding an additional panel in the future, but can only fit 2. I'll put a couple of shaded fans blowing in and a couple blowing out. I could go with a swamp cooler, but it takes a lot more power - I could run it for maybe 8 hours / day which should be enough - and it costs more. I've got over the winter to see how stuff works. I don't have to move into the camper for at least another month.

Thank you

mike95490 · August 2008

Re: cooling

Amazingly enough, the bondedlogic site, has no R or db values for their product.
(whoops - found it buried in a .pdf and the the R values make no sense at all:
each inch of thickness = R3.9

Sound - 3/8 pad = < pick a freq & pick a #, it's all over, and useless unless you can translate ASTM C-423 via Type A mounting & E795 >

My suggestion: sheet polyisocyanurate insulation (tan/brown color) - High temps, easy to cut. 1" =R6
I don't know about what to suggest for vapor barrier.

Fans. Get computer fans with intake filter option. You will want filtered air. Keeps bugs out too! Use the fan to blow in to the camper, at a low level, and have natural venting up high, letting the warmest air out. That will work with an open window, and no power too. In winter, use a precut piece of foam to block the vents. Naturally, the exterior portion should be raintight. UV light will degrade the foam.

Check local ordinances about "camping" on Public Streets.
Santa Barbara, CA, has a community partnership with local churches, to allow "camping" in church lots, except when the church needs the lots. (Sunday AM) Venice, CA, is going the opposite route, to ban camping, and the plan is to have cops roust and ticket sleepers, and ignore the drug crime. Santa Monica, CA welcomes the homeless, as long as you can pay for parking. Much of the city is restricted to "resident zones" where residents get a sticker to allow them to park for longer than 2 hours.

In that small of space, a couple of LED lights will do you fine.

FreeBrrd · August 2008

Re: cooling

I wish I had posted here before. I just ordered the insulation yesterday.

I'm not too concerned with vapor barrier. With the size, few seams in plywood. Only corners. I'll seal there and screw holes. I piece of plywood for the roof. I think I'm going to paint the plywood before I put it all together. Windows are a bit tough because the walls are slanted like the truck cab.

I also have the fans. I got ones with a mesh screen on the outside, either mesh or the usual circular thing on the inside. I saw the filter ones. I may add that or adapt something from the hardware. Most of the stuff that bothers me goes right thru any of the filters - hepa, etc. I've got some 1/8" plexiglass to cover windows & vents when it rains or if it ever gets cold enough. I haven't used heat or closed the windows in the last several years except when the landscape folks are out recirculating the dirt (using leaf blowers).

I got two cold cathode lights - like mini florescents - and a couple of leds for night lights. I have a few other leds that I had bought to put in my tool box (I'm a carpenter & need to find tools in the dark in the morning). I may use them if needed. I also have rechargable lights that can recharge in my storage unit. I was going to put in a skylight, but that would add heat (and expense and time...).

I appreciate the 'parking' information. There is an amazing amount of stuff online regarding the situation. The parking is the part that is the most intimidating to me. I'm removing the rear window so I can drive away without getting out of the camper and walking around to the cab. If I have the money left, I'll get the sliding rear window. Otherwise just a screen to keep the kittens from underfoot.

So what about placement of the insulation - on the top of the roof cavity or bottom? I find logic either way. I emailed the manufacturer, but have not heard back.

mike95490 · August 2008

Re: cooling

Insulate the roof. Your carpet will deaden floor noise.

If needed, add a roof shade, like the old Range Rovers. I guess a luggage rack with a tarp over it will work.

Urban "camping" articles:
http://tinyurl.com/62vdz8 http://tinyurl.com/5tcd4f http://tinyurl.com/6gjsx9

FreeBrrd · August 2008

Re: cooling

I meant, in the roof, put the insulation just under the plywood sheething at the top so the air flows under it, or put the insulation under the rafters ontop of the plywood ceiling so the air flows over it. I think you answered that in having the vents at the top.

Roof shade would cover the solar panel.

thank you

niel · August 2008

Re: cooling

just as in the case of an attic in your home you want the floor of the attic insulated so the outside air circulates in the attic above the floor of the attic (ceiling of camper). the vented space above the insulation helps to cool the attic and takes excessive moisture or condensation away with that circulation.
in the case of insulations with a reflective surface this mandates an air space also between your ceilng and the insulation between .5 inch and 1 inch. if you have a reflective surface on both sides of the insulation this allows it to reflect heat away coming in from the outside in summer and reflect heat back in during the winter.

FreeBrrd · August 2008

Re: cooling

that's what I had thought before I thought too much

thank you (again). no more thinking for a while

cooling

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