Author Topic: solar for hot water? (Read 5771 times)

northfifeduckling · « **on:** August 03, 2014, 03:51:19 pm »

We have 2 systems , 1/2 of the house runs on wood the other on oil/solid fuel combined as needed. I'd love to add water heating solar to at least one system. Can it be done on DIY or/and what would it cost? We don't have large areas of roof space left as the main south facing roof is occupied by solar pv.
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Just noticed the older thread - apologies for doubling up. I've now read the replies there but my main question is if it can be combined with a double system.
The thought of having to use wood and oil in the summer just to have hot water annoys me on each sunny day that I am wasting the resource from above...
I will pass on the technical info from other thread to the man so he can have a think but any new ideas for our circumstances would be appreciated.

sss · « **Reply #1 on:** August 03, 2014, 06:03:49 pm »

Have you thought about adding one of those devices that diverts your solar PV to heat the immersion first to heat the water?

northfifeduckling · « **Reply #2 on:** August 03, 2014, 06:11:50 pm »

I don't think we can do that as we're not off grid but on the feed-in system...

sss · « **Reply #3 on:** August 03, 2014, 08:44:04 pm »

http://www.immersun.co.uk/

Quote

The immerSUN monitors the electricity which is about to be exported to the grid and diverts it to the immersion heater

I think this is the doofar and it works with feed in system. I am sure other brands are available

Dreich Pete · « **Reply #4 on:** August 03, 2014, 08:52:01 pm »

So you just want your hot water to be from the solar HW system, is that correct. If so, then a single or double panel should be enough to heat your water. Remember, unless it is hooked up to a system to generate electricity via the heat exchange method (can't remember the proper name). The hot water is from the supply and fed to the well insulated tank. As such it is a standalone system that has no effect on the on-grid/off-grid systems and can therefore be installed by yourself.

We're looking into adding a solar HW system to pre-heat the water to the GSHP hot water.

northfifeduckling · « **Reply #5 on:** August 03, 2014, 09:31:50 pm »

That's correct, Pete.
Financially it might not be possible to install a panel on both ends of the house. The side with the oil/solid combo has probably the better roof (S/W) but the side with the wood stove system might be easier...
What would one of these panels cost and can it be done on DIY? Or what roughly does an installation cost?

regen · « **Reply #6 on:** August 03, 2014, 10:04:29 pm »

If you have a hot water tank or better still a thermal store then fitting an immersun type device is the cheapest way to go as well as being the simplest and if you are grid connected all the better. The immersun costs about £300 with fitting at about £200 max. and it will divert most of the spare kw via the immersion element. A 4kw PV system will gve about 2000kwh per year but you do need a 300litre plus tank with a bottom entry imersion to get the most out of it.

Regen

juliem · « **Reply #7 on:** August 17, 2014, 08:45:03 pm »

I had solar panels for the water installed 8 years ago .My main moan is that the dishwasher and washing machine are both cold fill...so unable to make use of the hot water. Also made the mistake of not getting a shower off the solar panels as shower needs to be below the tank to get enough water pressure(shower needed to be on ground floor) .That leaves us with an abundance of hot water and only being able to use it for having baths and washing the car.Luckily we do not pay for water as we have a borehole Also the tank will probably need replacing soon...awkward job and more expense. My ideal is a house without any water tanks anywhere....no risk of leaks. .
I have a woodburner with a back boiler which also heats the water in the tank...and there is also an immersion heater which if all else fails I can use to heat the water.
I think to get it right..you really need a new build.