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Ok, here's my insulation plan for my van
Walls: 1" Polysi Foam insulation
Ceiling: 2" Foam insulation
Air Circulation: Fantastic-Vent 2250

Trying to decide if I really need air conditioning, but I have no idea how hot I can expect it to get in the can at a given outdoor temperature. For some reason I'm thinking 20 degrees hotter in the van without the fantastic-vent, but I have no idea how much the fan will mitigate that.

Here are the average high temps for the places we will be staying on our trip and how long we'll be in that temperature

28 degrees - 1 day
47 degrees - 1 day
52 degrees - 1 day
61 degrees - 6 days
63 degrees - 8 Days
64 degrees - 7 Days
65 degrees - 14 days
66 degrees - 2 Days
67 degrees - 2 Days
68 degrees - 12 days
69 degrees - 11 days
70 degrees - 27 Days
71 degrees - 15 Days
72 degrees - 38 Days
73 degrees - 22 Days
74 degrees - 35 Days
75 degrees - 61 Days
76 degrees - 2 Days
77 degrees - 20 Days
78 degrees - 20 Days
79 degrees - 9 Days
81 degrees - 11 Days
82 degrees - 16 Days
83 degrees - 1 Day
84 degrees - 10 Days
85 degrees - 3 Days
86 degrees - 7 Days
87 degrees - 4 Days
89 degrees - 2 Days
90 degrees - 1 Day

I'm sure humidity factors in somewhere, but that aside, do you think we'll be in the hotter temps long enough to warrant an air conditioner?
I think elevation also plays a significant role as the suns radiation increases 4% with every 1000ft gained.
Ok, for now let's calculate for sea level and I can add the 4% per 1000' later
I've seen temperature changes upwards of 50° in the sunlight.

When I had a heavily insulated cargo van, by mid afternoon the indoor temperature would be in the 140° to 180° range, and wouldn't cool off to comfortable until just about sunrise. Even with the doors open didn't seem to help, it was like the insulation trapped the heat and continued to radiate it for many hours.

In my humble opinion, if you're traveling in weather that is going to be uncomfortable, insulation or not, I'd have both heat and air conditioning available. You just can't trust Mother Nature, and where you're planning on 80° weather, could turn into 120° weather. Being prepared is a better choice than being miserable.
(02-15-2015, 12:12 AM)Matt71 Wrote: [ -> ]Here are the average high temps for the places we will be staying on our trip and how long we'll be in that temperature


While I am amazed at the level of detailed research you must have done to get those numbers I have to tell you that there are still at least a dozen other factors that are going to affect whether you feel a need for air conditioning, including:

Are the temperatures you listed annual averages or the average for the time of year you plan to be there?

What is the expected humidity?

Will you have something over your roof most of the time. With all the solar you are planning on, I'm guessing yes.

Will you be parking in the shade?

Will you be parking next to trees or plantings that cool off the air? Some kinds of trees and plants transpire a lot more than others. That means they evaporate a lot more water from their leaves. This cools the air significantly. Riding my motorcycle around (when I had one) I have noticed as much as a ten degree drop when riding past well watered groves of water-hungry trees. Drought-tolerant and coniferous trees don't do this nearly as much.

Will your van be actively ventilated all day?

How cool does the area get at night and are you willing to allow the interior of your van to cool off down to the coldest temperature in order to dissipate as much of the stored heat as possible?

How much equipment do you plan to run inside the van? Is there a way you can sink some of their heat outside the van? For instance, mount your inverter and battery charger directly to the floor with no insulation between them and the floor, thus allowing them to radiate their excess heat out through the bottom of the van. (Yes, in the winter, you are going to wish you had that heat, so you gotta balance all the considerations.)

Do you and your wife radiate a lot of heat. Some people seem to be furnaces, whereas others seem to be cool to the touch most of the time.

You seem to be planning to haul a lot of heavy stuff. This will act as a heat sink. Once it heats up in the day time, it will take a long time to cool off unless you have cool air blowing directly over all that mass.

Finally, do you ever sleep? This research must take forever.

My advice is to leave room for an air conditioner in both your van and your budget. Then, if you decide you need it you can pick one up along the way.
The whole concept to solar oven cooking is a dark sealed box heated by the sun. We had one green van that got so hot inside that we would open all of the doors and wait a few minutes just to let the heat out before we got in. It was nice on those cold early mornings when the sun would warm the van up but we spent the rest of the day outside. Even the roof of a white van just radiates heat down on a sunny summer day.

Now if your figures are averages, watch out. Average where we go is 75 at best, records are in the 90's. By then our trailer heats up like a oven without fans or AC and it is white and insulated. That's why I designed our solar around the ability to run a AC. Normally we can get by with a third of the total watts without that big load.
The temps are averages for the month we will be there and are for the closest city. Some of the smaller towns don't have weather stations, so a few times i had to get temps for a few miles away.

I can get the relative humidity from the same place i got the temps, but it might take a while to compile everything.

The roof will be covered with solar panels, probably mounted on plywood.

The amount of shade will vary. The times when we'll be above 80 are kind of spread out. Some days will be in Sequoia National Forest, Arches National Park, Mesa Verde National Park, Denver and the Black Hills

Where we park wil depend on if we're on shore power or not. If we're relying on solar we won't be in shade, but then again we won't have the juice to run the AC anyway if that's the case. Unless we go back to bringing a generator.

We'll probably run the fan all day. The model we plan on using can sense the temp inside the van and adjusts it's speed accordingly.

The areas that are above 80 all get down to about 50 to 55 degrees.

I do plan to vent the area around the power station. Was doing it for the batteries, but venting some of the heat from the inverter sounds like an added befit.

I don't think we radiate much heat. My wife is cold most of the time which is one reason we're following the warmer weather.

I do sleep about 6 hours a day. The research does take a long time, but I like it. It's the first thing I look at every day.
One thing to keep in mind is that the van will have its own AC that might cool things down a bit when we are driving as long as we keep the access to the back open. We'll be driving quite often, but not for extended periods.

Has anyone ever trie putting reflectix on their roof?

Oh and we're 90% certain we'll have a white van
A word of warning about Denver. I don't care what the average is at any time of year, our summer highs are mid 90's into the 100s. Even now at mid winter we are having record setting highs in the 70's while the average is 44. This is why we go to 10,000 ft to camp, when it's in the 90's up there, it is 105 in Denver. The only time we camped at lower elevations in a heat wave we had hook ups thankfully. I had to drop the awning down as far as possible to keep the sun off the trailer at 6 am.
You can take a page from Bob's excellent work on van living, and have a white plywood stand-off panel above the roof. Safari vehicles in sunny equatorial Africa use this technique too - keeps direct sun off the vehicle's roof. Makes a convenient way to mount you PV panels too.
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