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Solar PV Water Heating

PostPosted:Sun May 12, 2019 6:18 pm
by ArchaicRider
Has anyone here had any experience of using any of the solar PV water heating add-ons?

I mean those gadgets that monitor the power use from / to the grid on properties that have solar PV and when exporting more than, say, 70-100 watts, divert that same excess power into a resistive (sp?) load such as an immersion heater.

I've been looking at Solar iBoost+ which looks fairly simple to fit myself. With a clamp on the correct feed wire by the mains in and a box to install by the immersion, as long as I can tell live from neutral from earth I should be all right.

I know that the payback for these is quite long when using gas for water heating but there is the environmental side to it too. With the country having quite long periods of coal-free electricity generation it would be nice if I could have periods of gas-free hot water production!

Interested in others' experience of these sort of products.

Thanks in advance

AR

Re: Solar PV Water Heating

PostPosted:Sun May 12, 2019 6:52 pm
by rjc101
I have a monitoring system from 4-noks called Elios4u that has this ability, I use it to turn a power socket on for battery charging from time to time. The product you list is a version of their own standalone solution https://www.4-noks.com/shop/solar-photo ... a/?lang=en

As we have a combi boiler the water heating side didn't apply, but the systems do work and help to ensure you use as much as you can rather than export it.

Re: Solar PV Water Heating

PostPosted:Sun May 12, 2019 8:36 pm
by Colonel Panic
We have been running a Solar iBoost for a few years and it is excellent; it halves what we would otherwise export - and with the way the subsidies are made we would "lose". It has paid for itself in spades.

Our hot water is ordinarily heated by oil. I have set the HW system to come on between 18:00-19:00, and so if there is any excess solar production during the day it goes in to heating the water, and if not then the boiler kicks in.

During approx 4.5 years (effectively 5 winters & 4 summers), our 16 panel 4kW system has generated a total of 18,300 kWh, of which 5,800 went in to heating the hot water, 5,800 was exported, and 6,700 was used by us. (During the same period we have imported 13,200 kWh).

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 9:28 am
by Sooty25
@ArchaicRider although I have no experience of the iBoost, I do know two of the manufacturers directors and some of their staff personally. It will do exactly what it says on the box and will be well supported. :thumleft:

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 10:33 am
by malcolmfrost
myenergi have a box called an Eddi which does that, they are also close to bringing out the Zappi which diverts Solar into electric car charging.

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 12:07 pm
by Trent772
And does anyone know how much these are and where you can purchase ? I have a tame coded electrician, don't need it installed.

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 1:32 pm
by Flyin'Dutch'
Amazon

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 5:38 pm
by ArchaicRider
Thank you to all, I'm quite confident now that it's the right thing to do.

Next I've to persuade Mrs AR that I'm allowed in her airing cupboard to fit the thing! :roll:

AR

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 5:54 pm
by Bill McCarthy
I haven’t googled but am interested in which would be more beneficial and cost effective - vacuum tubes to heat water or using solar panels to do the same. I have had the 6Kw wind turbine for the same period as CP and it has generated over 60 000Kw/hrs now. It has dramatically reduced my heating and electricity bills. I enquired of a local solar panels wind turbine installer and asked him about adding solar. He said he wouldn’t sell me them as they would never, or take a very long time, to achieve payback. I am still very interested in using a “spent” EV car battery for storage as highlighted on a previous thread - then solar might be worth it - provided these batteries can be had for near scrap value.

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 7:27 pm
by Flyin'Dutch'
Just been looking at the options (no solar panels but you never know) and one of these heating elements is about 400 quid and the steering is about another 300 plus installation.

For twice that amount you get a heat exchanger hot water boiler which is much much more energy efficient.

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 7:32 pm
by malcolmfrost
Bill McCarthy wrote:I haven’t googled but am interested in which would be more beneficial and cost effective - vacuum tubes to heat water or using solar panels to do the same. I have had the 6Kw wind turbine for the same period as CP and it has generated over 60 000Kw/hrs now. It has dramatically reduced my heating and electricity bills. I enquired of a local solar panels wind turbine installer and asked him about adding solar. He said he wouldn’t sell me them as they would never, or take a very long time, to achieve payback. I am still very interested in using a “spent” EV car battery for storage as highlighted on a previous thread - then solar might be worth it - provided these batteries can be had for near scrap value.

Where you live I guess wind is more reliable than solar! Down here my panels have generated 22kWh today alone, Ok it's been very sunny but I reckon that's really good, enough for around 60 miles in a Tesla and free!

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 8:08 pm
by Colonel Panic
malcolmfrost wrote:Where you live I guess wind is more reliable than solar! Down here my panels have generated 22kWh today alone, Ok it's been very sunny but I reckon that's really good, enough for around 60 miles in a Tesla and free!

How many panels do you have? I've generated 25.8kWh, and exported 11.4kWh. And even at 20:07L we are still generating 32W 8)

(Our system is nominally 4kW / 16 panel, but with ~3% transmission loss between the panels in a field and the house).

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 8:12 pm
by Trent772
Ordered - ta !

Re: Solar PV Water Heating

PostPosted:Mon May 13, 2019 8:13 pm
by Colonel Panic
PS Today's graph shows Mrs CP heating her studio early this morning prior to it being needed (grrrr), and how the Solar iBoost used a fair bit of what would others have been exported until ~13:00.


Image

Re: Solar PV Water Heating

PostPosted:Tue May 14, 2019 7:09 am
by Bill McCarthy
If I did go for solar I don’t think I could use its output, and Feed In Tariffs have disappeared. I have never known the wind direction to be stuck so long to the east and north east - we have had virtually no rain for two months (when it rains nearly every day at some point) . I have to phone in my turbine readings in a weeks time and this quarter will be well over £1000 return.
I am waiting for these EV car batteries to appear - then I will invest in an array of panels. The sun was up at around 05.30 this morning and it a cloudless sky at the moment.
Is there any benefit it making an array sun following ?