Solar heating for MH. (1 Viewer)

[Robert 314]

I am full time in my mh, travelling around France. I wouldn't say I,m economical with my LPG but I often wonder if there's a solar heating unit somewhere out there suitable for a motorhome. Anyone know of something?

 

[Mikeco]

Yes it's called the Sun but it's only available at certain times, apart from that you need gas.

 

[DBK]

Do you mean solar heating to give hot water? If so I guess a domestic system might be adapted but from memory they all use large well insulated water tanks to store the hot water. The whole system would be heavy and bulky I think.

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[dave newell]

Its probably not realistically viable. Even a large motorhome will typically only accommodate a max of around 500 Watts worth of photo voltaic panels, assuming (possibly in error but feel free to research and prove me wrong ) water heating panels to be similarly rated on a Watt/surface area basis you're going to struggle to generate any meaningful heat unless you're on the equator in mid July in which case you probably won't need heating at all. I have a 7 metre, very well insulated panel van conversion and in cold weather (5 deg C or less) it requires a minimum of 2KW heat input to maintain a reasonable temperature inside.

D.

 

[Deleted member 29692]

assuming (possibly in error but feel free to research and prove me wrong ) water heating panels to be similarly rated on a Watt/surface area basis you're going to struggle to generate any meaningful heat unless you're on the equator in mid July in which case you probably won't need heating at all.

It's a different type of system. Solar hot water is an indirect cylinder system with a cylinder full of an anti-freeze type solution which is pumped round the panels and the hot water heated via coils in the cylinder. It doesn't heat it to usable temperatures, just increases the ambient temperature so the primary heat source (boiler or whatever) doesn't have to do as much.

Even if such a system was viable for a motorhome the weight of it would be a killer.

 

[mitzimad]

in warmer climes a lot of people use a black water container left out in the sun to supplement there hot water demands

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[Deleted member 29692]

in warmer climes a lot of people use a black water container left out in the sun to supplement there hot water demands

You see them a lot at festivals where they're called "solar showers"

Never used one so no idea if they're any good.

 

[Barclaybasher]

You see them a lot at festivals where they're called "solar showers"
Never used one so no idea if they're any good.

 

[mitzimad]

It's a different type of system. Solar hot water is an indirect cylinder system with a cylinder full of an anti-freeze type solution which is pumped round the panels and the hot water heated via coils in the cylinder. It doesn't heat it to usable temperatures, just increases the ambient temperature so the primary heat source (boiler or whatever) doesn't have to do as much.

Even if such a system was viable for a motorhome the weight of it would be a killer.

thats not quite true in hot sunny weather a good solar will get extremely hot which is why its usually mixed with cold for use
early direct systems suffered badly by overheating which is why they are now pumped so that flow can be stopped when its getting too much heat

only the coils a small header and panels contain glycol the cylinder is still filled with water
the biggest draw back for a motor home is they all work on bulk storage which would be impractical in a motor home

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[dave newell]

It's a different type of system. Solar hot water is an indirect cylinder system with a cylinder full of an anti-freeze type solution which is pumped round the panels and the hot water heated via coils in the cylinder. It doesn't heat it to usable temperatures, just increases the ambient temperature so the primary heat source (boiler or whatever) doesn't have to do as much.


Even if such a system was viable for a motorhome the weight of it would be a killer.

I understand all that, I was simply commenting on an energy level harvest point of view. Ignoring the weight issues you probably couldn't fit enough panel surface area to a motorhome to harvest sufficient energy to boil a kettle once a day never mind provide heat in meaningful levels.

D.

 

[Deleted member 29692]

thats not quite true in hot sunny weather a good solar will get extremely hot which is why its usually mixed with cold for use
early direct systems suffered badly by overheating which is why they are now pumped so that flow can be stopped when its getting too much heat

only the coils a small header and panels contain glycol the cylinder is still filled with water
the biggest draw back for a motor home is they all work on bulk storage which would be impractical in a motor home

A few years ago, when the systems were relatively new, a developer near here put systems in a couple of high end (bloody expensive) barn conversions. There was a manufacturing fault in the cylinders which caused the coils to corrode in a matter of weeks so that the glycol mixed with the fresh water. This made two things happen. The first one was that the tap water tasted of anti freeze. The second, and far more visually impressive, was that fresh water pumped around the panels. It happened to be winter so the panels full of fresh water froze and split. There was then a little warm snap, funnily enough over the Christmas holiday, where they thawed out again. The waterfall feature down the front of these new barn conversions was a sight to behold

 

[Deleted member 29692]

I understand all that, I was simply commenting on an energy level harvest point of view. Ignoring the weight issues you probably couldn't fit enough panel surface area to a motorhome to harvest sufficient energy to boil a kettle once a day never mind provide heat in meaningful levels.

D.

Absolutely. Unless, as you said, you happen to be sitting on the equator.

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[pappajohn]

You see them a lot at festivals where they're called "solar showers"

Never used one so no idea if they're any good.

Yes, they are....but you dont need to add any cold water to your shower.
Used one a lot on a yachting holiday around the Ionian islands.

 

[pappajohn]

This made two things happen. The first one was that the tap water tasted of anti freeze.

Why would you drink from the hot tap.....hot and cold are isolated.

 

[Deleted member 29692]

Why would you drink from the hot tap.....hot and cold are isolated.

No idea. It wasn't my house. Perhaps they noticed it when showering?

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[pappajohn]

Never thought about the inevitable gob full of water while showering.

 

[Reallyretired]

I suppose you could use a black bag type solar shower on the roof and feed the pipe in through the washroom window. Only useful when its sunny though.

My brother has solar water heating on his roof in sunny Yorkshire and reckons it's great, a bit heavy for mobile use though.

 

[TheBig1]

fitting an engine linked calorifier as used on boats would be a better idea

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[Robert Clark]

We've got solar thermal panels at home
Great in the summer but less useful in the winter for heating.
A system linked to your engine heater would be a good solution - alternatively invest in decent window insulation - keep the warmth in