idea

thats how solar pool heating works, the temp of our pool heating is well above 60
degrees when it comes down from the roof.
gmd

At about 300ml per metre for 19mm pipe, to get say 10L for a shower your would need to coil up 33 metres AND park the van in the sun. Perhaps a kettle of boiling water in a bucket topped up with cold is easier (thats what we do & use a 12v shower from Jaycar)

It's done for some swimming pool heaters but you end up covering the whole roof with pipe.

Good thought though :)

Adrian

Yeah but you normally get to the camp spot in the late afternoon and then the water will take a loooong while to heat up, if at all. Maybe if you stay a few days it will work ...and then it would have to be in summer.

Boil the billy, make a warm water mix in a bucket and use 12 volt shower. Or use plastic solar shower

Or get about two metres of small copper pipe from an air con blokes bin, bend it into small coils so it fits into a small saucepan, billy etc. Plumb that into your normal 12v shower after the pump and presto! Costs nothing! Takes about three minutes to heat the saucapan (on your normal gas cooker) filled with enough water to cover the coils of copper and then you can pump as much water as you like through the coils for continual hot water... no one misses out! Packs up pretty small. Have even got a small $5 metho burner now so that once the water is heated up on the gas cooker it can be transfered to the metho burner placed beside the shower area. Handy if it is away from your cooking area. There's enough heat in the metho burner to keep the water in the saucepan hot. Plus the metho lasts a long time so you dont have to carry much of it.

Someone here is using poly pipe on the roof of the bus they're converting ready for their retirement years. The above comments make it look like it won't be the best option. I don't know what type of van you have Chips, but why wait until you stop - you could have it working all day if your van can accommodate it.

A guy in rural WA sells a design for a DIY household solar HWS made of black poly pipe.

if the pipe was warm in white , paint it black see the temp go up heaps.

on a hot day walk on the tar with no shoes and you will burn your feet , walk on the white like and it very comfortable . Since white reflects the suns rays , it dosnt penetrate the plastic , in black it will almost double the temp

I got a call out to a farm property that was having problems with the over temp switch cuting out on a water heater. The farmer had run a temporary supply to a shed in black poly and left it in the sun, the water temp was over 80C by the time it got to the water heater. Be a prety hot shower I reckon.