Solar panels connect to stove pipes

Palerider

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I am trying to simplify and save some money by installing solar panels to provide summer hot water, I don't want the grant or new water tank, they are complicating my needs, the quote I got had too long a payback for me, less is more for me.

So, my back boiler stove has pipe work running to my existing tank in a convection loop all very successfully heating the water when there is a fire lit, I'd like to connect solar panels and all associated pipework into the hot pipework from the stove. This can be done by breaking into the side of the house and making the connections to the existing hot pipe from the stove, a non return valve close to the join will ensure flow in one direction only from the panels.

My logic is that as heat enters this pipe it will join the existing convection loop from the stove thereby heating the water.

Am I simplifying this or will it work, I can box in and insulate all solar pipework outside.
 

jpd

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The usual way to do this is to install a hot water tank with two convection loops - one for the boiler, one for the solar panels. The solar panel convection loop is filled with glycol so that it will not freeze and cause damage in the winter-time, so it would not be good practice to combine the two
 

Leo

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jpd spot on here. Is your back-boiler the only alternative to electric immersion element for water heating? If you have a central heating system that also heats the water tank, you would need a 3 coil cylinder.
 

Palerider

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Thanks for replies, I have electric immersion heating but like us all have a reluctance to use it too much....

The glycol might be the issue, I wonder if I added anti freeze to the heating system if that would resolve it.

It is a large cylinder but my gas/solid fuel is combined using one coil, it is a Frankenstein system, if I can I don't want to touch the cylinder just break into the heating pipe work after it leaves the stove.
 

Palerider

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The hot from the panels fed through the hot pipe at rear of stove, the return piped through the return at a T to the stove ?
 

JohnJay

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I'm no plumber, but I don't think this will work. For one thing, how will you stop your stove from heating your solar panels?
 

SparkRite

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I'm no plumber, but I don't think this will work. For one thing, how will you stop your stove from heating your solar panels?

<snip>............. a non return valve close to the join will ensure flow in one direction only from the panels.
............<snip>
Unfortunately for the OP he is over simplifying the operation of solar panels/evacuated tubes.
 

Palerider

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I'm no plumber, but I don't think this will work. For one thing, how will you stop your stove from heating your solar p
A non return valve on the cold water return to the panels would ensure no heat returning to the panels.

@SparkRite, I agree that I am trying to simplify, I have had a sales guy out to me saying this is not the way to do it but to me this is a bespoke system that is not undoable, I just don't want to spend on needless work.

I'm not interested in grants or dumping a perfecting good hot water cylinder and that frustrates the installer who is trying to make my required install fit the SEAI box.

I want panels to heat my water feeding into an existing system.
 
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Leo

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You will lose efficiency in your panels if you don't use glycol, plus you'll run a significant risk of boiling the system on hot days. Even with glycol panels can be damaged if circulation fails for any reason.
 

MangoJoe

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1. Why turn down the grant?
2. No idea of your household occupancy, but there's a huge advantage in having 300+ litres of water at 70 degrees - Def consider the tank upgrade again in my view. Also do you have enough heating coils as is? Incl OFCH etc?
3. You said yourself the existing stove pipework works well - I wouldn't be inclined to tap into it. My solar pipework is flexible and runs (unobtrusively) across the attic dropping straight into the tank - What's the issue with this principle?
4. Why reinvent the wheel? Can you not just let a good plumber implement a tried and trusted system that has been proven to work well everywhere else??
5. This proposal is seeking to economise while simultaneously refusing available grant aid and seems to aim to be obstinately in defiance of accepted practice. It might well work flawlessly, but I can just as easily imagine it being plagued with problems and I cannot understand the attraction of taking this route.....
 
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Palerider

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Thanks for the replies, I now understand my approach was too simplistic and will withdraw to contemplate.

The quote I got was to change out my tank and run pipe work though the attic and included the grant but the cost/ return was too long.

I will seek other quotes.
 

jpd

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To do it properly, you do need to change your tank - if this isn't economic, then so be it
 

Palerider

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Curious what is the view on this approach.

Solar PV ten panel system creates dc into a hybrid converter which converts the dc to ac Using a hybrid inverter and smart technology it first priortises power to the home with excess to battery storage and immersion, there should always be hot water as your existing immersion will be run by the electricity generated by the panels..

When more power is required than generated by the panels the excess will first be taken from the battery storage then from the grid.

No new tank or plumbing required, there is wiring and tech/smart meters required.

I got a quote today of around €10000 after a grant of €3100 and am going to get other quotes, I'm very interested..

Interesting that when I asked for references from satisfied customers I was told they could not provide this due to GDPR, not what I or anybody else whats to hear when references are required.
 

RedOnion

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Interesting thread over at:
 

roker

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You are not taking temperature difference into account. Most of the time the solar panels will be below the boiler temperature and pre heats the water tank and the boiler tops it up to temperature, the solar pump switches on when the panels are 5°C above the tank temperature ie. Solar panel 35° tank 30° or solar panel 65° tank 60° throughout the temperature span
 

Palerider

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Whilst I was simplifyin, I think the Solar PV panel set up with hybrid inverter battery and diverter to immersion is a good wiring solution without impacting plumbing and I am proceeding that way.
 
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