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Solar Water Heating "I did it my way."


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Paul, thermosiphon solar hot water systems are great and that is a very simple and effective design to implement.

 

I did build one in outback Australia about 40 years ago but the design I built had a lower straight feeder with about 2 inch spacing between risers to the upper collector tube which carried the hot water to the tank.

 

At that time the recommendations were to use black paint for the backing and to cover your frame with glass, similar to current commercial designs.

 

Because most of Australia is desert or semi desert, temperatures below freezing overnight in winter, the circular design that you have shown was not as efficient as the straight riser design and I have no idea how they determined that.

 

But given we are in the tropics what you have should be able to scald you if you are not careful :)

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That'll work.  I have one concern: if you follow the spiral design for the panel then gravity may not work well (if at all).  I would tend to go for a bank of parallel pipes so the flow of warmer water never has to 'flow against gravity,' i.e. downwards.  I know it's more trouble to make.

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SkyMan

I was thinking of something similar to your top picture but remove the tank/faucet and insert a swimming pool. For that I thought it would be best to have both the cold and hot sides coming from/to different areas of the bottom of the pool so the hot water would rise through the pool heating the whole thing. Swimming pools here tend to be just a little on the cool side for me and the covered ones quite cool.

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SkyMan

That'll work.  I have one concern: if you follow the spiral design for the panel then gravity may not work well (if at all).  I would tend to go for a bank of parallel pipes so the flow of warmer water never has to 'flow against gravity,' i.e. downwards.  I know it's more trouble to make.

I think the spiral design lays flat and the movement of the water comes from the hot water expanding.
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I was thinking of something similar to your top picture but remove the tank/faucet and insert a swimming pool. For that I thought it would be best to have both the cold and hot sides coming from/to different areas of the bottom of the pool so the hot water would rise through the pool heating the whole thing. Swimming pools here tend to be just a little on the cool side for me and the covered ones quite cool.

 

Pool Water Heater Design. You won't need any additional pump. You just install a bypass valve, then route the water through the panels and back to the pool. 

 

 

Paul, thermosiphon solar hot water systems are great and that is a very simple and effective design to implement.

 

I did build one in outback Australia about 40 years ago but the design I built had a lower straight feeder with about 2 inch spacing between risers to the upper collector tube which carried the hot water to the tank.

 

At that time the recommendations were to use black paint for the backing and to cover your frame with glass, similar to current commercial designs.

 

Because most of Australia is desert or semi desert, temperatures below freezing overnight in winter, the circular design that you have shown was not as efficient as the straight riser design and I have no idea how they determined that.

 

But given we are in the tropics what you have should be able to scald you if you are not careful :)

 

No doubt. It is going to be hot coming out of the first panel (60 meters) of tubing. I can only imagine how much hotter out of the second one!

 

 

That'll work.  I have one concern: if you follow the spiral design for the panel then gravity may not work well (if at all).  I would tend to go for a bank of parallel pipes so the flow of warmer water never has to 'flow against gravity,' i.e. downwards.  I know it's more trouble to make.

 

No gravity at work here. Pressurized system. The panels will be on the roof. The water will be pumped via the ShurFlo, up to the roof and into the panels. The pump will come on when the valve in the shower is opened, pushing the water through the tubing, down to the bathroom and to the valve.

 

 

Water storage, hot or cold, you need to be aware of

Legionnaires' Disease

 

http://www.hse.gov.uk/healthservices/legionella.htm

 

Woolf, I would imagine the heated water would be higher than 60°C, wouldn't you agree? I mean, I am not sure, but I would imagine it would be heated higher than that, before it gets to the ends of those tubes.

 

Other precautions I will be taking, will be to make sure screens are on all tanks, make sure all tanks are sealed from any available light to prevent algae growth. I guess I could chlorinate the water, either manually or automatically injecting it? It was my understanding that I would not need to concern myself with that, here. Any other input you have about this, would be appreciated.

 

As a side note, when I was in Australia, God only knows what you would find in the huge tanks Aussies used to store their rain water in. The water also had a taste that took a bit to get accustomed to! I may be wrong here. But, I don't believe they did anything concerning chlorination, or any other preventative measures, prior to the water going into the tanks. Also, I never even saw a first flush type system on any home, during my time in Australia. 

 

 

I think the spiral design lays flat and the movement of the water comes from the hot water expanding.

 

No. Pressurized pumping, It will be similar to the way the original designer built his. The exception is, the panels will be on the roof, rather than a berm.

 

 

Is Algae build up a problem in a system like that?    

 

Algae can be a HUGE problem in rain water harvesting tanks. One must use preventative measures to prevent algae growth. Keep the tanks as dark as possible. No sunlight should be able to shine into them. Use screens on any inlets, outlets, or overflows on the tanks. 

 

---------------

 

One thing that has crossed my mind about this particular system is, the temperature / pressure getting too high during the day, while the water is not being used. I am a bit concerned that the tube may burst at some point, if either gets too high.

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mikejwoodnz

 

 

One thing that has crossed my mind about this particular system is, the temperature / pressure getting too high during the day, while the water is not being used. I am a bit concerned that the tube may burst at some point, if either gets too high.

 

a simple blow off valve with a whistle to alert you will fix that.

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As a side note, when I was in Australia, God only knows what you would find in the huge tanks Aussies used to store their rain water in. The water also had a taste that took a bit to get accustomed to!

LOL.. where I grew up we relied on a maximum 12" rainfall to fill a tank for drinking and cooking. The balance for laundry, showers/bath even brushing your teeth was from a dam which, no matter what we did was a milky brown color from suspended clay particles.

 

But what we found in my uncles rain water tank after it sprung a leak and had to be drained to fix was the carcase of a possum. Lord only knows how it got in the tank.

 

And prior to that we always used to reckon the water was the best tasting... :ROFLMAO: :ROFLMAO: :ROFLMAO:

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a simple blow off valve with a whistle to alert you will fix that.

 

I'm not runnin' a train station here! :P

 

 

LOL.. where I grew up we relied on a maximum 12" rainfall to fill a tank for drinking and cooking. The balance for laundry, showers/bath even brushing your teeth was from a dam which, no matter what we did was a milky brown color from suspended clay particles.

 

But what we found in my uncles rain water tank after it sprung a leak and had to be drained to fix was the carcase of a possum. Lord only knows how it got in the tank.

 

And prior to that we always used to reckon the water was the best tasting... :ROFLMAO: :ROFLMAO: :ROFLMAO:

 

After I saw that they found a dead cat, a dead bird, and other "similar" foreign objects in his 25,000L tank, I decided I would just leave the drinking of rainwater to him. :D

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Paul

 

Legionnaires' Disease is just something that you need to be aware of

specialy for showers the buggers get into the lungs via small droplets or mist

 

There have been cases where the hot water temp has been kept too low

and people have been sick

 

I think that the water temp in your pipes will be so high that the buggers will be killed

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Water storage, hot or cold, you need to be aware of Legionnaires' Disease

 

It's a good point and in Australia most outbreaks have occurred in evaporative air conditioners when the maintenance schedule did not adequately provide for cleaning/washing the moisture absorbent pads.

 

Modern evaporative air conditioners have a built in ability to carry out regular system flushing on demand and, as Paul says, the water temperature in his solar hot water unit should exceed 60C and in any case it is recommended to establish a regular flushing cycle of any water based system.

 

I am not sure how often that flushing cycle should occur but if you check the commercial manufacturers they tend to err on the side of caution.

Edited by No Fixed Address
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I think that the water temp in your pipes will be so high that the buggers will be killed

 

But, on the cold water side, the water stored in the tanks prior to being pumped into the house? That water will be well within acceptable parameters.

Now, you have me concerned a bit. I hadn't thought of this before you posted it.

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As long as mist or droplets dont get into your lungs there is no problem

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