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Forum Index : Solar : Solar space heating
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KarlJ Guru  Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
OK this is next on the list. ideal scenario for me would be hydronic and 100 or so evacuated tubes on the roof, even with 2nd hand bits I'm lloking at $15K here.....outside the budget. Next would be direct air heating, I have found a couple that look reasonably priced, looking for some feedback for you guys. 1)Solar venti -european thing http://www.solarventi.com.au/ was considering the SV30 which is about 3m x 1m x 100mm thick. and worth about $2900 + installation 2)the aus made http://www.sunlizard.com.au/content/solarclimatecontroloverv iew.html similar dimensions at about 1550 x 1200mm (2 collectors) these are about $4200 + delivery and installation. From what I've read the sunlizard would probably work better for heating as it is recycling air from inside the house hence the warmth kept in and the solar venti is drawing in outside air and heating/drying it, providing more airflow through the house. I'm inclined to go for the solar venti on price as obviously its one helluva lot cheaper at about 3/4 the $$ and looks simpler to install. I have also looked at the one that draws heat in from the roofspace but due to their distributor not even knowing what he was in for when he came to quote, I was that disgusted I showed him the gate. Luck favours the well prepared |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Solar space heating is a snap and you don't need a lot of fancy stuff. The key is your working fluid. I did this in Florida years ago and I used motor oil. It can be heated to around 900 degrees F in a closed system without any problems. I used a tracking concentrator and sooner or later I'll build another one and post the pictures and tutorial here. For now, put your thinking cap on and maybe just use a flat-plate collector. If you put your storage tank (insulated in 5" of beach sand of course!) at the top of the system, it will 'thermo-siphon' and you won't need a pump. The heated oil is passed through a standard fin-and-tube exchanger with a blower attached to spread the hot air around your house and you're done. That's about as easy as it gets. Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Loomberah Regular Member  Joined: 11/06/2008 Location: AustraliaPosts: 43 |
I've got 78 evacuated tubes, which easily boils the water in the 250l tank in the mornings on a sunny day, but that will be solved when I plumb in the 1000l stainless steel tank I picked up at an auction for $350. 2 X 24 tubes into manifolds + a 30 tube unit with 250l tank cost well under $4000 new. I've set it all up to thermosyphon, eliminating the need for a circulating pump on the solar heating side of things. The 1000l tank will also be part of the thermosyphon. At the moment I run a circulating pump through 2 hydronics radiators in the house and blow a small fan over them to extract quite a bit more heat than still air convection/radiation alone. That barely keeps the water from boiling on sunny days, even in winter. The house is still under construction, not many curtains and only some walls insulated and lined, so it cant keep the house warm all night on cold frosty nights, but does make it bearable in the afternoons and evenings if there has been some sun during the day. 6 hydronics radiators and a controller will eventually be installed, all up cost of that was about $2500 new including 200m of Pex-Al-Pex pipe. I'm planning on using all that heat in summer to generate electricity, but havent decided on exactly how yet- steam turbine, steam piston engine or Stirling engine. The only problem is with all these options is there is nothing suitable available to purchase, so its a DIY project, and steam turbine may be the easiest for me to build. So, $15000 with 2nd hand parts? Sounds like someone is trying to rip you off big time! 
Gordon Loomberah weather +solar&UV, astronomy, photography, organic farm |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Hey! Here's a novel approach to solar heating: http://www.cansolair.com/ This fellow uses recycled soda pop cans in an effort to capture solar energy to heat his dwelling. He sells a product, but the idea is so simple you could DIY I'm sure. Give it a look-see. Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Eamon Newbie  Joined: 20/09/2009 Location: AustraliaPosts: 1 |
Karl7, from a product point of view, I will have to agree with you. The Solarventi SV30 is a fantastic heat producer and also is completely controlled by the sun, therefore no electricity bills. The other advantage is the product will not have any paint fumes coming through unlike what may come from the other mentioned products. The air that comes in from a Solarventi is clean, fresh, hot dry air. The other benefit is that the air is crisp dry and in turn kills allergy thriving spores, bacteria and dust mites. It is a solar dehumidifier. I may be biased but have good reason. I have used this product to resolve damp & condensation problems where reverse cycling air conditioners have failed. Brought natural space heating & clean air to cold overshadowed houses. All now running maintenance and cost free. We are now offering and installing the full range of Solarventi products in NSW, www.solair.com.au If you need more info, just ask..... |
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| greendreamin Newbie Joined: 02/02/2008 Location: AustraliaPosts: 20 |
hey have a look over on otherpower i have seen photos and some info on a few DIY ones overthere (sorry too lazy to search)they looked good had some performance figures and they were working in the snow, maybe worth a look if your interested.. Stu |
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| KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
I bought a fan! mounts in the roof space and moves warm air into the house so far my results are nothing short of awesome! winter=looser but spring and autumn a winner, no more gas heating. Its called a solectair and cost about $1100 plus inatall which took all of 3 hrs, keys into the existing evap air ducts and successfully heats the whole house. Karl Luck favours the well prepared |
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home heater Newbie Joined: 03/03/2010 Location: AustraliaPosts: 9 |
I painted my roof black, covered it with good glass from the recycle shop and pump heat into my house with a Mistral 6220-0 self shutting fan. It even collects heat while it is raining. Hot water is collected from the hot roof space with a few half inch copper pipes and the hot air blows through a car air conditioner condenser to collect more. Next part of the project is to extract hot air from saved hot water at night. My goal is to do without firewood, and I am sure it can be done with plenty of hot water saved from the days collection. This thing really heats the house, you cant leave it on flat out. It is thermostat controlled. Dont buy a system, make your own. do it yourself |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
What about the solar pool heating systems with the black tubing on the roof should work well with some heat exchangers in the house. Be rather basic to setup and would fit to any roof. Pete. Sometimes it just works |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=Downwind]What about the solar pool heating systems with the black tubing on the roof . . . The material used for solar heating pool water is usually plastic. To get the most out of a static panel system (active or passive) it really needs to be covered with glass, Lexan or some other clear solid that keeps the wind off the heating surfaces. This elevates the amount of heat trapped, but unfortunately, the plastic won't handle it and it'll burst. If you were to use copper tubing instead of plastic, the sky's the limit. Of course, the price tag will be up there in the sky somewhere too! I think the most cost-effective measure would be to scavenge some used potable-water solar panels, make sure they are in good condition and use them on the roof with oil as a working fluid. The oil will hold more heat before it wants to make a phase change than water will. If you plan ahead, you can install panels so they are either in parallel or series, remembering that in series, the oil will get scorching hot by the time it reaches the containment vessel. Also, be aware of the melting temperature of 50/50 solder or whatever the panels are constructed with. You don't want a panel to burst and cover your housetop with hot oil! By the way, I've only ever run oil in panels at ground level. Up on the rooftop may be inviting a visit from Murphy! I'd then store the heated oil in a containment vessel and to heat the house, I'd run the hot oil through a heat exchanger and mount the blower so the heated air enters your dwelling ON THE FLOOR. (A little note here: This type of system works on volume passed through the exchanger. It is better to have the same-size tubing in the exchanger as is in the rest of the system. You want lots of hot oil to pass through this quickly. Even if it doesn't exchange all its heat, it'll work better than trying to pass it slowly through smaller tubes. I've tried both ways and larger is better.) Most FAU (forced air unit) systems put the heated air into rooms at small vents on the ceiling here in the States. That makes about as much sense as taking a bath with your toaster; it's suicide. Heated air rises and as it does so, having entered at the floor, it passes its heat to the surrounding air. The "used" air should be recovered from near the ceiling and recirculated through the heat exchanger, then passed out again ON THE FLOOR. By the way (again), I have used water as well as oil and it works the same, except you run out of heat sooner. I had a small-ish unit I used to heat my garage workshop using water from my domestic water heater (also in my shop area) and it worked like a champ. I tossed it out by mistake, but I may build another one and if I do, I'll post some pictures here for you to see. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| neil0mac Senior Member  Joined: 26/12/2009 Location: AustraliaPosts: 210 |
Just a thought. Using Macs motor oil as the fluid, pick up some 20+ year old Solahart panels (or similar, cheaply - on eBay/solar water companies? - panel and glass already assembled) and go from there? (It is usually the tanks that fail in those systems.) |
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| KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
I even had 100 evacuated tubes I thought I could use for this but summer is a real challenge to not blow up the tubes (water in glass and low pressure system) would have worked with a 1000L storage tank and constant circulation and various layers / connections to house / pool / hot water system. I could quickly see thousands of dollars dissappearing. If I do take it on at some point I will use heat pipe type evacuated tubes and keep the water out of the tubes. Karl Luck favours the well prepared |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
KarlJ As we get closer to summer, I had already intended building a very small (1 sauare meter) flat-plate collector and tank at the top, much the same as the Israeli Solahart system. I intend to throw in a twist or two, but it'll function very much the same. When I do, I'll post pictures and yakity-yak here so you can take a look at it. I used to have a concentrating collector, but it needed a tracking heliostart, which I cannibalized to build something else I thought I needed more. One of the "twists" will be a carry-over from that project. When I retire, I intend heating my entire home (a travel trailer which is about 200 square feet max -- hee, hee) using the thing I will soon build. Stay tuned. Edit: The new solar collector will cost no more than $100 by the way. That alone may be reason enough to stay tuned, eh? Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| lamont Newbie Joined: 22/07/2010 Location: United KingdomPosts: 1 |
Thanks for the information you have shared.I need some assistance regarding this.Can you please help me...? Pool solar heating |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
lamont Perhaps if you tell us what you want help with, it might help us help you. My Chinese made crystal ball is broken,  maybe someone else have a working ball?? 
Pete. Sometimes it just works |
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| jdaley Newbie Joined: 23/09/2010 Location: AustraliaPosts: 2 |
Mac what do you do in summer to shut the system down. It would be very hot otherwise? John Daley Melbourne |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mack On your solar hot water collector, I have made a small one using two car radiators in a suitable enclosure with a 6mm glass front that I picked up from the demolition shop, it was a sliding door, with a nice frame and all, for $30. A little pump with a 60 C thermo switch mounted in the panel so when the radiator gets over 60 C it turns on the pump and circulates to the storage tank. A bit rough and ready but it works well, even in winter. The storage tank is 200 ltr about 50 gal, it came from the dump op shop for $30 also. I think you could find plenty of dead HWS in your line of work. All the best Bob Foolin Around |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=jdaley]Mac what do you do in summer to shut the system down. It would be very hot otherwise? "My" system runs on the hot side anyway, since I use something other than water for the working fluid. If I wanted to shut it down, I'd toss a blanket over it. A unit large enough to heat my little travel trailer need only be about two feet square (collector size) with a "receiver" (tank) no larger than about 6 gallons. By the way, if you put the receiver higher than the collector, it "thermo-syphons" and you don't need a pump. Just a quick note on building these things: using used A/C evaporators or condensers is not the best way to accomplish the task. There are too many turns and interruptions in flow. A better way to go is to have one pipe in and one out, with the body of the collector a set of tubes all running the same direction with no turns or obstructions. I can't build anything until after March 17th 2011, but when that time comes, I'll post everything. Please be patient until then. Thanks. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| home heater Newbie Joined: 03/03/2010 Location: AustraliaPosts: 9 |
We live near Portland, on the south west coast of Victoria. It is a cold climate and the most important thing for creature comfort here is heat. This blog is not what I am going to do, it is what I have done, my Solar Space Heating System is now three years old. I have a good collector, my north facing roof. I painted my roof black, covered it with toughened glass (sliding glass doors etc) from our recycle shop and pump heat into my house from under the iron roof. I have 30 square meters of glass, assuming 50% efficiency I can collect 15 kW around midday in full sun. This amount of heat does not take long to heat our small house. It does not need full sun to work and provides a surprising amount of heat in overcast weather. It has to be a very dull day not to provide any heat, and so far this year (May, 2012) we have only two days where the fan did not start. Hot air entering the house (via the bathroom) passes through an air to water heat exchanger (a recycled car air conditioner condenser) and warm/hot water is pumped to a storage tank, also in the bathroom. The bathroom has become her clothes dryer as well now. We can shower in a 30 deg bathroom when it is 15 deg outside. This thing really heats the house, you cant leave it on flat out. It is thermostat controlled and heats the house to 30 deg almost every day, even during the winter. Small heat collection systems that sit on your roof are not worth the money for heat output. A couple of computer fans will not move enough air to heat your house, I have been there. If we see the sun for an hour during the day in winter, I need to heat my house quickly, and a whole roof collector does that. Feedback for MacGyver using oil as a heat transfer medium, water holds over twice the amount of heat than oil, yes, you can heat oil to a higher temperature than water but my system doesn't get hot enough to boil water. Heating oil to a high temp requires concentrating reflectors. Using oil complicates the system with another heat exchanger. Only two other substances hold more heat than water, hydrogen and helium. When it comes to both a heat transfer and storage medium, you cant beat water. Hot water cylinders leak heat, I have two cylinders in the bathroom and they leak enough heat overnight to keep us at 20 deg in the morning. I have an unheated aquarium inside and the temp of the water hovers around 25 deg. Also in MacGyver's post, you have your air flow the wrong way around, better to introduce the hot air against the ceiling, soaking the ceiling and insulation with heat to slow your heat loss into the evening. The coldest air in the house is on the floor. A floor level vent will allow cold air to escape as the warm air pushes it out from the ceiling down. The introduced warm air is fresh air from outside, positivly replacing old cold air. No air is recycled and the air is replaced many times a day. I soak my house and contents with heat to last all night. Feedback for Karl, if you seriously want to solar heat, dont buy a Solarventi or Sunlizzard, they are too small, they fail when you need heat the most, when it is overcast and cold outside. When that sun peeks out for an hour or two, you have to pump heat, and not with computer fans. $4,200 for a Sunlizard? Hardly cost you $200 to make one of those, dont waste your money. Evacuated tubes are not worth the extra cost, flat plate collectors will heat plenty of water and you can pick them up second hand, often for nothing. Don't buy a system, make your own. Feeddack for Jdaley, a room thermostat turns the system off at your prefered temperature setting, or you can turn the system off altogether. You dont have to get on your roof and throw a blanket over it. Hot air rises so the only way to get your solar heated air down into your house is with a fan. I do overheat deliberatly during the day, knowing that we have a cold night to come. It was 9 deg outside this morning 20 inside from soaking the house with heat yesterday. I do live in a well insulated house (tin shed!!!). Anybody wants any advice or photos is welcome to email me. (jfscott(AT)optusnet.com.au)I have made my system mostly from recycled bits and pieces, a good start is an old air conditioner for both the fan and the condenser for a heat exchanger. The air door is actuated with an electric car door window winder. A Chinese solar controller controls the water part of the heating system and works very well. It is an SR868C8Q, off eBay. I can help with ccts to wire up a system, there isnt much to it, a thermostat in the roof to sense when there is enough heat to start the fan, another thermostat in the house to stop the fan at your preferred temperature, and a relay to operate the air door motor. Retired now, I was an electronics tech. Alternative energy is my hobby and I an currently making a 4.5mt blade for a 2.5KW wind turbine I bought 2nd hand. I use autocad and can draw files for anybody wanting them for laser cutting. Hi to Glen, I have a simmilar background to you, starting with the PMG in 1965 as a technician in training. javascript:AddSmileyIcon('  ')
do it yourself |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Alan Good post, sounds like you've got some interesting projects on the go. I like the solar air heater, making good use of the existing roof space. Yeah its surprising just how hot that type of collector can get, I have 2 solar water panels waiting to be put together and currently leaning against the shed, only a couple of square feet is exposed to the sun, and they get hot! I've been to Portland, nice part of the country, very pretty. Yeah, it was cold too, we went for a walk on the beach one windy morning and my ears have never been so cold
Glenn Really need to find the reason for that "javascript:AddSmileyIcon('')" text that pops up occasionally, got me beat. The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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