New Solar Thermal Panel Project From Hawaii!
Steve has sent in this great solar thermal panel project, the great thing is it costs less than 30 dollars and provides a large amount of his hot water needs. Great stuff Steve. Use this space to leave comments on the project.
- Posted in : Pictures, Positive Change, Renewable Energy, Sietch News, The Naib
- Author :The Naib
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Does the plastic pipe break down to a harmful substance. ? I think copper may be safer for drinking.
The plastic pipes are used in irrigation and as such will not break down. Copper pipes of this length would have cost thousands of dollars. It could however have been down with copper, the plastic however works much better and is cheeper.
Nice piece pf work Steve. Only drawback of course is that you have to wait till mid morning to have that shower :-). I trust you have tried additional storage for the project? I’d be most interested to hear how/if its come on.
I have recently moved to New Zealand, and have been playing with something quite similar to your project for a short time now. It was refreshing to come accross your submission. Initially I want something to assist with heating a pool. Experiments so far look good, though I’m working on getting a permanent flow of warm water through the sunlight hours. At the moment the unit I’ve built can heat 10 gallons of water at 20 deg C to about 36 deg C in 60 mins of sunlight – though as you say, if the unit is left stable with no flow – the water will come out extremely hot. Will perhaps post the project when I make some more progress.
Cheers
Shane
Awesome, I wonder in cold climates if antifreeze (glycol) would work, or would it boil? you could make a heat exchanger out of an old fridge evaporator coil placed in a tank of water.
VERY Inovative,, One possible improvement to get some storage without a pump, would be to take the center end of the pipe and raise it about two or three feet, run lines to top and bottom of old hot water tank, and presto , Thermal Convection. This would make a pyramid shape of the tubing (pipe) , and, as the water heated up , it would go to the top of hot water tank and displace the colder water in the bottom of tank, back to the inlet (outside of coil) Glass here in Canada is cheap, (free if you look hard), However, heavy clear plastic would probably work to cover coil. And The thin plastic thermal safety blankets make extremely good reflectors, Good to see others experimenting with solar etc’ ,, All the best from Canada Ehy !
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hello,
i’ve made one but it doesnt work very well.
is a plastic ore glass sheet realy nessesarely for the functionality of the solar heater??
greetings from Holland
Hello Maurice:
If you live in a very sunny and hot place you might not need the glass top sheet, but I would say that without it you will suffer a very high loss in efficiency. The glass serves to trap the heat inside the unit, making it heat up faster and stay hot longer. Without the glass, any heat absorbed by the collector is going to radiate rapidly back into the air. Also the glass helps to keep wind from cooling the collector.
I would say in Holland you may need an insulated box AND a glass top sheet in order to get good results. This project was made in a tropical place, your climate is a bit cooler and will require greater methods of heat trapping.
Hope this helps.
ok thanks a lot.
(today it took me 4 houres to get 10 L of water from 15 to 50 degrees celcius, without glass ore plastic sheet) i will try with it.
At what elevation are you in HOVE?
I’d be careful using polymer pipes, especially for heating. Leeching of hormone-disrupting chemicals is more common in higher temperatures, so I’d recommend using metal pipes and painting them black. Other than that, fantastic idea.
Also, you might want to look into PV for your power needs, because it seems that electricity is quite expensive. And you obviously have the solar resources.
We’re thinking of using a similar system to extend swimming time in our pool each end of the warm season. I reckon the best way would be to first make a layer of polystyrene boards for insulation, cover them with aluminium foil to reflect any IR heat, then coil the hose and cover that with glass, sealing the edges with strips of polystyrene.
However, for aesthetic reasons, we’d prefer to use a dark green hose. Now, I realise that black absorbs heat more readily, but would the difference really be so great?
Steve
rock on, Last year I bought about a quarter mile of irrigation tubing 1 inch thick outside diameter. I was going to use it gor a geothermal heat exchange, tube was oging to be burried underground. Could I use this polyethelene tubing for a large scale project like yours? Allothether the tubing cost me about 160 dollars. I think 1000 feet of 1 inch tube (inside diameter = .875 inches) pie r ^2 would tell me that each foot holds roughly 7 cubic inches of fluid. or .03 gallons. I could store about 40 gallons in that length I think. Only thing that bothers me is will the tube being exposed to uv light for so long render it useless after a while?
I live in Belgium and even I can heat up water substantially with a similar panel (of course much more insulated and so on) but I can’t use the water that is heated for washing or drinking. This has to do with safety (legionalle etc) so I was thinking about other ways to use this hot water. Is there something else I can do with hot water? Is there a way to utilize the energy somewhere else or transform the energy to electricity?
At he moment I have hot water but no use for it…help me make something out of this project. Thank you all in advance!
Cheers.
Yavuz,
This problem can be overcome by setting up a system that stores the heat you’ve collected or transfers it to the domestic water that is safe to drink. The fluid that circulates through the coil is reused and is in a sealed system. In colder regions it’s common to add ‘anti-freeze’ to this fluid as well.
I’m not sure you will have the space, but here is an example. The hot liquid would be pumped through a coil in a barrel full of water transferring the heat to the barrel. The domestic water line would also pass through this barrel before it entered the normal heating system. This “preheats” the water, saving you energy and keeps the two systems completely separate.
This addresses several of the criticisms of the design (and the earlier version) including the growth of Legionella, contamination due to Freon or lubricant in the lines, or the use of plastics not rated for potable water.
It’s a more complex design that many commercial units have used for years, but it is a real improvement.
I believe that all plastics photo degrade over time. Not sure if it will get in the water but it clearly best to use copper for drinking water. However how often do you grab a cup of hot water from your tap?
That plastic tubing was not designed to run at high temperatures so be careful about mixing it with any water you plan on drinking. THere are some PEX tubing types that will safely work at elevated temperatures and may still be inexpensive. You could certainly find a way to use less tubing and absorb the solar energy with a metal plate. Try a sheat of maybe 0.04 aluminum simply painted with flat black paint and then silicone your plastic tubing onto the back side (perhaps one tube run every 3-4 inches). That way you could minimize the amount of tubing you need and so you could still stay in budget with something actually designed to run at high temperatures.
Hawaii is a perfect example of a location where very simple and inexpensive solar heating ideas can work. Obviously this same design would not provide much hot water in NY or MN but in an area where temperature rarely go below 20 C and are mostly in the 30 – 35C range it could be quite effective. Now of course if you want to do something about your cooling bill then you will need a design able to run at much higher temperatures so that you can run an absroption chiller or stirling engine.