Solar water heater

[pellow]

Anyone use a solar water heater? Looking at the evacuated tube type, can you get any grant if its for farm use and no domestic? Looking for anyone with experiences good and bad

Thanks

 

[f0ster]

if you are claiming a tariff you can not have a grant. they are worth while, you get free hot water, if you are going for a large array you will need somewhere to dump the heat when everything is up to temp.

 

[pellow]

if you are claiming a tariff you can not have a grant. they are worth while, you get free hot water, if you are going for a large array you will need somewhere to dump the heat when everything is up to temp.

can you let it boil over to dump heat?

 

[f0ster]

on a good day the array manifold can reach well over 200 deg if it has nowhere to dump heat, you would need something equivalent to the kw rating of the array. for a domestic install it is not usually required but an unused rad will do it, for a larger install a hot water fan coil heater, the smallest one has a max output of 20kw but it can be turned down to 5kw or anywhere in between. when you apply for FITs one of the questions asks about any grants received.

 

[pellow]

on a good day the array manifold can reach well over 200 deg if it has nowhere to dump heat, you would need something equivalent to the kw rating of the array. for a domestic install it is not usually required but an unused rad will do it, for a larger install a hot water fan coil heater, the smallest one has a max output of 20kw but it can be turned down to 5kw or anywhere in between. when you apply for FITs one of the questions asks about any grants received.

thanks, what would you call the size of a domestic outfit? the one I'm looking at is 2 metres by 1.5 metres

 

[f0ster]

that is only about 2kw depending on manufacturer. the array is sized to the storage tank usually.

 

[whatnow]

We've got an east/west design, similar size to what you're proposing. Heating a 300ltr DHW tank(think 300, maybe 200?). Used it for about 16 months now. Quite happy with it. You need to be wary of over heated water and either put a thermostatic mixer on the outflow so you don't get scalding water unexpectedly out the hot tap or be very wary. No grant here

 

[pellow]

anyone else using an evacuated tube heater? anyone recommend make and supplier? lots of cheaper ones on ebay

 

[___\0/___]

Hi @pellow did you ever fit this system? How is it working over the winter period?

 

[Dave645]

I have No clue if he did, but now you would be likely better off fitting solar electric and just use daytime solar to heat hot water with an immersion heater, it’s far less complex and you can use electric in many ways.
running cables is far easily than pipes, solar dumps, etc.

 

[pellow]

I haven’t fitted one, still planning too, if you use hot water I believe it’s the most effective renewable energy source

 

[Dave645]

I haven’t fitted one, still planning too, if you use hot water I believe it’s the most effective renewable energy source

I have one it’s very good, I have my solar tank setup as a pre heat for the cold mains to my GSHP so even if I get low winter effect where I see 30 degrees in my 700l store it saves me money by preheating the cold mains by that amount and, as they said it can go very hot, I have a solar dump setup to stop the system operating in over heat which cuts the roof off, when the tank hits 95 C
I have a pump that clicks in at 70C that’s just a ground coil loop, with a pump. I also have a way for the heat pumps tank to be also heated directly by the solar as it primes my hot water loop, as it has a pumped return to prime hot water to distant bathrooms. This goes through the heat pumps tanks so solar can heat both tanks to 70 C no problem even with the solar dump clicking in.
it’s amazing what heat you get on cold winter but sunny days

 

[Dave645]

Sunny cold day, actually a few days after that posts only 6 C outside in the sun, frost on the ground in the shade, the sun managed to heat both my tanks a total of 1000 litres of water tanks to 60 C by tea time. I am not saying they started from below 20 c but the roof can get hot even on cold days. To get to that temp means the roof was hotter. than 60c even on that cold winter day.

I fitted a velux solar roof system ( great flashing kit) with pump without there tank, I used a bigger tank designed for my system. it’s a pity I don’t think they do it now.