Would this cool a caravan at all to any real extent.

[zionosis]

So I have a 20ft caravan and it gets really hot here in Australia. I actually built it from a caravan that was stripped. I have heavily insulated it. I want to run it fully off solar power.

Anyway there is a cool 500w air conditioner that is for sale but it's only in the USA. Literally I have found no low wattage air conditioners here in Australia (besides one that is $1300, The American one is only $130).


Anyway to the point. If the caravan is in the shade and it's heavily insulted if I was to build this, would it actually do any amount of cooling that is worth mentioning. I know Peltiers are not that effective but still wondering if it would actually reduce the temp by 6°C.

http://s20.postimg.org/o5645cilp/Untitled_1sdfsdf.jpg



I know that Peltier modules can't even move as much heat watts as they use which is bad compared to good air conditioners that can move 4w of heat to ever 1w used in power, Or at least the cheap air conditioners still move at least 3w for every 1w of power used.

But from the efficiency of a Peltier a 136w peltier is said to only be able to move 80w of heat. Then on the hot side you have 216w of heat to remove.

 

[beetlejuicegr]

I have a feeling that you can cool your caravan with solar panels but i dont remember where i read it. Oh they were using the whole solar panel as peltier device or peltier attached there. You can google around for that, you can also see that peltiers are a good experimental solution INSTEAD of solar panels completely but i am not physicist or electrician.

80mm fans perhaps are not ideal, i know that 120mm on the price range of 20ish $ are ultra silent and transfer more air (CFMs) on the same power

 

[zionosis]

I have a feeling that you can cool your caravan with solar panels but i dont remember where i read it. Oh they were using the whole solar panel as peltier device or peltier attached there. You can google around for that, you can also see that peltiers are a good experimental solution INSTEAD of solar panels completely but i am not physicist or electrician.

80mm fans perhaps are not ideal, i know that 120mm on the price range of 20ish $ are ultra silent and transfer more air (CFMs) on the same power

The high power 80mm are better because they would operate in a smaller tube. It's about the amount of power behind the fan. In these cases you need a fan that can really force the air. A centrifugal fan would be the best but there are none suitable for this. 120mm case fans are not suitable for this as they are too large and I would need a larger tunnel/tube to put them in and they don't have much power behind them. Touch them with your finger and they are very weak and are designed for more open usage.

Also solar panels cannot be used as a peltier element. They are not even similar in how they work. A peltier element can be used however to produce electricity if you apply heat to it. But it's not that efficient.


I have found my solution anyway. I found a proper air conditioner that has 1.6kw of cooling and it only needs 400w to run. This is perfect and will cool my van down very fast. 1600w of heat removed is better than the 240w of heat the peltiers would move.
I think the peltiers would work but I would end up being disappointed in finding out that the temperature in the van might drop 2°C over a few hours. lol.

At least the air conditioner will do it properly and can run from the panels.


I am not going to peltier route but keep in mind when I was talking about those 80mm fans I am not talking about your typical one. I have the typical ones and mess around and they are weak as ever. I am talking about the really thick high powered ones and they were to be inside a tunnel that was about 90mm diameter and the heatsinks on the original image post were not meant to be exactly that one used but more like this.

Also there does happen to be high powered 120mm fans I have found. Wouldn't call them case fans though. If I was to use the original heatsink in the original image and had a larger tube/tunnel then the 120mm fans I would get would be like this.

Uses 10 watts also. very high powered for it's size.

The typical 120mm case fans just move air gently and slowly, But still because of their size still move a decent amount of the air.

They only use about 2w typically and I in fact have one in my van in a really high window acting as an exhaust to get rid of the hot air. It runs straight from two little panels on the roof.
Those little panels cost me $6 and when the fan wears out I can just replace it since they cost $2 on ebay. Being sleeve bearing is why they wear out, but they are cheap and still last a few years at least.

 

[COLGeek]

Typically, solar units provide a charge to a bank of batteries and then into an DC/AC inverter to power the caravan. How much battery storage do you have with your rig?

 

[beetlejuicegr]

I would like to see CFMs for the fans you are mentioning. (plus you dont need too much either btw, thermodynamics..)
and one more question, here in Greece we do get 30+ under tree so i dont know if all this effort of yours for 6celsius less will be worth the trouble.

Dont forget the air you are taking in, isn't of a stable temperature. Are you sure a 36celsius going down to 30celsius will be fine? In my experience anything above 26 is ..