DIY Solar Heat exchanger

[svengl]

I am planning to add a solar Heating system to my house.
I have a Gas Boiler. I would like to add a insulated water Drum where I would then have two coils in. One for the Solar loop and one for the Hot water tank intake. The Idea is to use the Water Drum as a heat storage during the day and if hot water is needed during the night or especially during the Morning it will preheat the water going in to the water heater.
Questions:
1. What are pro's and cons of a water heat storage?
2. what size would I need?
3. what size Coils should I use? (copper pipe ½;5/8? Single or triple parallel?)
4. Are there any plans for this kind of a heat exchanger
5. My thought was to use a big Plastic Drum, insulate it, do all of the Fittings thru the top, have one over flow to a drain that will double as overflow increase of a leak and as a Vent for moisture vapours.
Thanks for any comments

 

[kevindgas]

&

 

[Agile]

This site and most of us are located in the UK where the Queen lives!

Our standards and practices for using solar energy are probably very different from those where you are.

It would probably be better for you to find a good internet forum in the US if not in Canada.

Tony

INGENIEUR CHAUFFAGE

 

[svengl]

Thanks for the replies

I was hoping to get some suggestions where to go...

I think for the stage that I am in, it dose not realy matter if I am in the UK, US or china.

My design is not going to involve any presurized Vessel (except the Coils) And I dought that the water in the Tank would reach boiling temperatures..

Any way If some one has any suggestions where else to look...
Or some expiriance please let me know..

Greetings from the Cold (-20C) Canada

 

[kevindgas]

And I dought that the water in the Tank would reach boiling temperatures..

if you believe this then i'm glad i'm not living near you!!

my own system has had over 100C degrees on many occassions
and plastic tanks are not suitable in any form

 

[Norcon]

See this thread..............
//www.diynot.com/forums/viewtopic.php?t=143805

 

[Paul Barker]

It's a simple enough thing to divert the flow to a heat dump when the water store is up to a specific temperature.

In England it is clouds which are the bugbear, although the sun is relatively low in the sky right now we only get sight of the sun about one day a fortnight. So my solar store reaches about 20 degrees c 13 days out of 14 and 80 degrees C the one day the sun is out.

By all accounts in much colder places where the sky is clear possibly like where you are, solar panels are much more productive. It is sight of the sun which counts.

 

[svengl]

Wow temps over 100C…
That is exciting; I thought that it would be way less…
Ok, so plastic drums a no no. What are the limitations? Will the Plastic get brittle? Pex is used for Hot water? And it is under pressure. There would be no Pressure on my Drum.
What is a heat dump?
The reason why I am looking into this is our weather situation, it seems it is nearly reversed to England.
I live on the Prairies (Alberta) and here we have lots of Sun. I think I would rather have problems with Snow on the Panels and how to get it off.
As I am thinking of only preheating the intake to my main Water heater, even 20C seems to be a benefit.
My goal it to build this all by my self and try to build this as cheap as possible and therefore not to concerned about the final efficiency, so no expensive store bought solar boiler.
Thanks for all the comments, still rying to read thru th link thanks

 

[Agile]

Most plastic ( pex ) types of pipe are only rated for up to 80° C or less and at low pressures.

Of course your plastic tank cannot exceed 100°C if its open to the atmosphere.

However, you seem to think that plastic is easily able to stand even 100°. The reality is that most soften very seriously and if not designed for the purpose will deform and collapse.

Solar energy needs very special techniques, not even soft soldered pipes! We have to take a special course and assessment to qualify us to make solar installations.

Tony

 

[kevindgas]

Untitled

• kevindgas
• 6 Mar 2009
• 1

Untitled

• kevindgas
• 6 Mar 2009
• 1

just a couple of pics with my panel on overheat! 108C panel temp 64 top of cylinder and 66 bottom of cylinder

have a years temp records. with cylinder temp above 90C and hot water pumping round house still had to dump some water on 1 occasion when panel was 140C and cylinder at 102C

 

[BigBurner]

Untitled

• kevindgas
• 6 Mar 2009
• 1

Untitled

• kevindgas
• 6 Mar 2009
• 1

just a couple of pics with my panel on overheat! 108C panel temp 64 top of cylinder and 66 bottom of cylinder

have a years temp records. with cylinder temp above 90C and hot water pumping round house still had to dump some water on 1 occasion when panel was 140C and cylinder at 102C

What is the setup and sizes?

 

[BigBurner]

Look at this web site for good DIY systems:
http://www.builditsolar.com/

 

[svengl]

Thanks
This is a great resource and I have now so many more Ideas... And so little time..
I found here a few answers to my questions:
Build heater coils link:
http://users.telenet.be/hagim/zonne_energie/heat exchanger.htm
I assume this would be a heat Dump?
http://www.apricus-solar.com/html/solar_heat_dissipator.htm
Where would you send the exes Heat?

PEX Stagnatation test
http://www.builditsolar.com/Experimental/PEXCollector/StagnationTest.htm
And there are a few suggestions of heat storages out of Plastic.
Thanks Sven

 

[Agile]

By all means play around with that kind of DIY fun!

The amusement of that last web site is that the panel efficiency is deliberately made lower just to prevent lower stagnation temperatures.

Us qualified solar installers have to fit systems which will be safe and give a long life without failures.

A DIYer can do what he likes but if we were to fit yor plastic rubbish we would be likely to have expensive law suits.

A firm in the UK was heavily fined and put out of business after claiming that customers could save on their hot water and heating costs if they bought their solar systems.

Tony

 

[kevindgas]

A firm in the UK was heavily fined and put out of business after claiming that customers could save on their hot water and heating costs if they bought their solar systems.

Tony

not just the one tony at least two from dorset went that way