I live in UK and wish to incorporate solar hot water heating into fully pumped central heating system. Do you think that the proposed changes shown in the attached would work without an expansion vessel and an air vent. Please note that the gas boiler has already got an air vent installed to the pipe work. Also attached the gas boiler electrical diagram/programmer incorporating the 2 port zone valves and solar controller.
Incorporate solar hot water heating into fully pumped central heating system
- Thread starter SBT
- Start date
OzSolar
Whatever you did, that's what you planned.
Many of us will not download attachments.
OzSolar
Whatever you did, that's what you planned.
I was only able to spend a few minutes studying it so I'm sure there's plenty I'm not seeing.
If the evacuated tubes are on your roof, they will be the highest part of the plumbing system therefore you will need a vent there.
Do you not currently have an expansion tank? Is that what 3 and 4 are? It's been while since I fiddled with this.
You will have to have an expansion tank somewhere in the system. You may have to install one on the solar loop if there a situation where the two-way valves can end up isolating the solar from the part of the system that has an expansion tank.
Here's probably the most important part of my advice.... Space hearting with solar often fails to be even remotely worth the hassle and expense. I've got a mountain of pumps and parts from systems people paid me to remove to support that statement. The challenge is that the peak demand is directly opposite the peak resource. If you're doing this because it's a fun project, then go for it and ignore this old curmudgeon.
Keep us posted!
WindWizard
Solar Enthusiast
Some changes need to be incorporated with what you are proposing. You are using the same coils for the boiler as well as the evacuated tubes. That will not work. I have a similar system with seperate coils for the boiler and also for the evacuated tubes.
The fluid that goes to the Evacuated tubes on the roof needs to be a glycol mix to prevent freezing.
You will need to purchase a new indirect water tank with two sets of coils.
Also you will need a seperate expansion tank, and an air Seperator on the roof.
Another item that I have that is needed is a UPS to keep the circulator pump going when the power goes out. If you lose power on a sunny day, then you will produce a lot of steam and destroy your glycol mix.
The fluid that goes to the Evacuated tubes on the roof needs to be a glycol mix to prevent freezing.
You will need to purchase a new indirect water tank with two sets of coils.
Also you will need a seperate expansion tank, and an air Seperator on the roof.
Another item that I have that is needed is a UPS to keep the circulator pump going when the power goes out. If you lose power on a sunny day, then you will produce a lot of steam and destroy your glycol mix.
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I am not a heating engineer, but (from my limited experience in such matters) totally agree with what @WindWizard said ^^^^. The fluid in the solar panels will need to a) not freeze and b) not boil.
Furthermore, as you don't have a sealed central heating system, your circulating water in the CH pipes will be full of crud from oxidisation and electrolysis (not to mention the remnants of the odd decayed mouse that fell into the expansion tank) and hence is not suitable for piping though the fine pipes of a solar panel.
Furthermore, as you don't have a sealed central heating system, your circulating water in the CH pipes will be full of crud from oxidisation and electrolysis (not to mention the remnants of the odd decayed mouse that fell into the expansion tank) and hence is not suitable for piping though the fine pipes of a solar panel.
Apologies if I'm stating something you already know and your aiming to do it differently, but what your trying to achieve is extactly what a thermal store is designed to do, along with a number of other major advantages, I can explain if it's useful. Im a plumber by trade and have some experience.
The main issue I see with the above diagram though is the amount of crap that builds up inside solar thermal panels is going to damage the boiler internals in next to no time. Solar thermal requires quite regular flushing. There's afew other potential schematic problems when it comes to thermal syphoning, but practicality wise. You could look into incorporating a plate type heat exchanger to keep the two seperate.
Other options would be fitting a twin coil cylinder, a thermal store as mentioned or look into a plate heat exchanger.
The main issue I see with the above diagram though is the amount of crap that builds up inside solar thermal panels is going to damage the boiler internals in next to no time. Solar thermal requires quite regular flushing. There's afew other potential schematic problems when it comes to thermal syphoning, but practicality wise. You could look into incorporating a plate type heat exchanger to keep the two seperate.
Other options would be fitting a twin coil cylinder, a thermal store as mentioned or look into a plate heat exchanger.
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