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Topics - mikenash

#1
Hi Guys

If you have off-grid and time & space on your hands - then you don't have to be very efficient, especially if you live on your own

Where I live there's lots of sunshine & I have a water supply from an elevated spring that gives me a 2-bar head - or maybe a bit more

So I have a "solar shower" with the solar part outside in the sun and the shower part inside in a conventional shower cubicle with hot & cold taps etc etc

The "solar panel" is a rectangle of 8mm black plastic sheeting measuring 1400mm X 1600mm, more or less - on a timber support frame, aligned to the sunshine, on which is wound 100 metres of 20mm black "alkathene" poly pipe - ordinary farm stuff - in a big, flat, sun-facing spiral.  It's held flat on the black plastic sheet by about a million cable ties

Cold water at 2 bar goes in and - when there's direct sunshine - really hot water come out and goes to the shower cubicle.  The water's hot-enough that you have to feed in quite a bit of cold.  There's enough hot water for a good shower and then enough left over to think "well I might as well stand here until the hot runs out as both the water and the energy are free

Of course there are two downsides:  There's no storage of hot water - it's just direct on line.  And it only works when the sun shines.  But, since I have a wetback on the stove for winter or overcast, and since I'm on holiday whenever I'm there - who cares.  When the sun shines you can have a shower

It has worked well for years.  And. since there are no moving parts, it will still be working well when I'm dead

Next, then, is a similar panel, probably mounted flat, and a nearby small insulated tank into which I would like to think water will thermosiphon, getting hotter and hotter with each cycle, whenever the sun shines.  I guess it's probably only 10% efficient in turning solar energy into hot water - but if it's simple and it works, then who cares?

My question is - does anyone have experience with a low-tech, thermosiphoning, pump-free, water heater?  If they do - I'd like to hear about it.  No sense re-inventing the wheel

Cheers, Mike
#2
I'm interested in the grounding/earthing question too

I have solar + inverter.  From time to time I use a Chinese Honda-clone petrol generator as well

The "wiring" in my shed is carefully done but there is no earth because there is no switchboard - rather there's an extension flex with a 10A plug which either goes into the inverter or the generator.  At the other end of the extension flex there's an RCD

I have been told both that I should and should not run an earth stake at the generator; also that I "could if you wanted" run an earth at the inverter

To my way of thinking - if there's fault current - the RCD will trip.  I don't see what contribution an earth stake will make unless there is a switchboard and a path to neutral/earth so that current can flow to blow a fuse or pop an overload

But I'd be interested in the thoughts of better-qualified folks

Thanks, Mike

T