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Forum Index : Solar : Deciding if I should build this solar heater
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| Davo99 Guru  Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
That's Kinda the thing. I didn't say 500W, I said 500Wh in reference to what Roger said about the array running 15 Min before the stored heat was used up. If it's only generating a KWh on an overcast day, then wether the fan runs or not I'd say is irrelevant. A Kwh of thermal energy into his home over even 6 Hours wouldn't raise the temp a single degree so IMHO, trying to capture that heat is pointless when even if you do, it will make no difference. I don't know what winter time radiation is where I or he is but I'd bet my house it's not remotely near 1000 w M2 and that's the dilemma. I'm guessing its probably around 400W M2 on a sunny winters day so if one were getting a tad over a kwh every 3 hours, I question the effectiveness of that in the areas we are looking to heat which are large rooms at a minimum and ideally making a dent in heating the whole house. I'd be pretty happy to get 500W M2 even 4 hours a day. I put up another 5x 270w panels today which are the standard 1X1.6 m2 Which is 8m2 and if I could get 4Kw of heat out of them, I'd be laughing especially seeing that's only half the array of 10 Panels I want to do. I think I'm going to be lucky to get that much thermal energy in October, maybe November and I sure won't be interested in warming the house in those months. I can't see the thermal energy I could recover being near that and again referring to what Roger said which I experienced today, an overcast day, I doubt if it would be much more than about 50W M2 and that's what I was referring to. On these days where we want the heat the most, there is so little available I question if adding another PV panel to drive the fan is worth it? Even if the fan is blowing air warm enough to be in the range required, I think there is going to be so little in actual Kw HOURS generated over the day it's not going to make an Iota of difference to the temp of a room let alone a house. I'd sure LOVE to be wrong though! As in the case of the array I am putting up, 16 m2 if it is doing 50Wh That's 800 WH over the day and if it's doing 100wh, that's that's 1.6 Kw all day. I don't think that's going to really take the chill off my little office let alone the house. What I was trying to opine is that putting on an extra panel to recover that and then having the problem of the fan blowing way to hard on a sunny day is not worth the trouble for the minimal and basicly useless amount of heat that would be recovered on the bad days. You win some, you loose some, you blow the living snot out of some, but in this case, I think it's a definite loss. Still, I was in the en suite Icebox earlier thinking how stupid cold it is in there and if I could get say 400Wh x 5 Hours, 2kwh a day in there, I'm sure it would be less of an icebox. whether that's 1o warmer or more, remains to be seen. In your case I'd say it has definite potential to save money and I more than get the feel good value. In my mind, one thing the roof recovery does is get back some of the lost heat through the ceiling we always hear about. That said, Like anything else solar reliant, I think it will be useless on the overcast crappy days as well BUT, on the days like we had here yesterday where it was quite sunny but still cold, it's a definite winner. My point was it would do nothing to put out the fire, even if you had 1000 people doing the same thing. It's too little to affect the critical mass. Exactly the same thing with this instance of heating. You have to overcome the losses before you increase the warmth and I don't think the amount of heat that would be gained on a crappy day would even go near that. Should that be the case, then whether the fan ran or not would make no difference to the end result. I get that too! Heard it a million times with my Veg oil proclivity. People want to make out your hobbies are taking you away from paid work as if one works every waking moment and does nothing else. In the case of the Veg, The money it saves me and what I have to earn taking away taxes, I'd have to be on a medical specialists income for it to actually COST me money. Never had such a well paying Hobby ( maybe solar comes a good second) ever and what it has allowed me to do and the freedom it has given me is huge. Sure not every hobby is like that but as you point out, it's a hobby and not intended to have an ROI. That said, the closer we can get to our goals in our hobbies like this, the more rewarding they will be and the more satisfied we will feel. Least that's how it works for me! :0) EDIT: Seems my estimation of winter radiation was pretty close to the mark. Found a chart that says Sydney in July which is the lowest radiation month is 380w m2 with a max of 4.1 for a seasonally adjusted array at an angle of 60o. That's what I was thinking for the array I set up today, making it steep. Rogers potential Yield will be closer to 350w M2 in winter for his location. That being the case, on a sunny day, with the 400W, 2 m2 Panel I intend to test with, should get around 3.2 Kwh Plus whatever I can make with the electrical energy. That should be 100Wh or 3.8 Kwh total. That sounds suspiciously good. Using 2 panels would be entirely practical and now we have a very worthwhile amount of thermal energy that WILL definitely make a difference.... on the sunny days at least. Quite enthused by those numbers to give it a red hot go. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Thanks Tony, I might have to order one of those. I was hoping ... but it is a pretty gutsy motor with quite a bit of friction to overcome with the brushes. Yes, maybe ... though I purposely left it in the same plane as the tube array because that's how it will be on the roof ... but it's going to need some finetuning. That's a good point ... but I think that maybe there is a limit to how much heat the tubes can store, perhaps depending on the temperature in the sun. eg if the day is mild and only 25 degrees in the sun, the tubes will only get to say 35 ... and it won't matter how long the sun hits them, they may not get any hotter ... ... but if the sun has a bit of bite ... they may keep accumulating until they get to 70 or 80. So it is possible that if the fan had been running ... it may have been able to draw out heat at that rate for the whole time. Of course this is all theory and probably nothing like that at all.  That is true, but I am going through the process of trying to understand how it all works and just hoping that one of these odd things will be a clue as to how to eke out more power ... so an extra 200-500 watts, on top of what I might already be getting could be useful over time. Has been the same here too. Yesterday and today have been really poor, just glad I'd had a good run up til now or I might have given up on the idea. I'd have to agree too that it has feelgood value. It has been a buzz to have a couple visitors and to take them up to the lounge and let them experience the warm air flow ... and then explain how it works. Both were quite excited about it. And it does depend if winter is going to be all like the last couple days ... or whether we will get a good sprinkling of sunny periods where the device can significantly warm part of our house. Even if winter is poor, the last couple weeks have shown very good results ... so the lead up to winter and heading out of winter when we do get cold but sunny days should definitely be worthwhile ... ... bearing in mind I aim on fitting one three times this size ... and if I can make the control automatic ... it's all gravy from there. Cheers, Roger |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
I did a few different things today. After Klaus's comments, I put a datalogger up in the ceiling to see what temperatures are like up there. Then I dragged out another panel to hook up in parallel because I couldn't get the fan to start this morning ... just too much cloud. Even with two the fan wouldn't run. I wanted to see if the tubes had built up heat so I used an AC fan on the outlet to suck air through ... and that was enough to jump start the DC fan. There wasn't sufficient heat in the tubes anyway ... more cold air again ... so I shut it down. I also fed a thermistor temp sensor mid way down into a tube to see exactly what temperatures were in there. Should have done that ages ago. Mid morning it was only 35 degrees. The fan was switched off so it wouldn't blow cold air and when I came back at 12:30 it was at 57. I switched on the fan and it ran (7.3V on two panels) ... and finally nice warm air inside. After 3 mins the tube temp was down to 47 ... and a few more again, 44. At the time the outlet temp was 25.2. I disconnected one panel and the motor stopped ... so I reconnected it. Later I was working and heard an unusual and loud racket outside, so went out to investigate. Thought it was a truck breaking down out the front or something. First thing I noticed was it was nice and bright out there ... but I couldn't hear anything until it started up again. I raced up to the heater and realised straight away that the fan was the problem. Seems the sun had come out and really powered up the poor fan. The noise was the shaft tearing out the hub of the fan and the fan bouncing around inside the housing melting the tips of the blades!!! Scrub one fan blade. It has nothing to hold it on the shaft anymore. Bit sad really after all the work of putting it together ... still serve me right for leaving it unattended. Live and learn. So it's back on an AC fan again. Maybe I'll have to build my own box for the standard Commodore motor and fan after all. Cheers, Roger |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Something I never understood until recently was that ... ... The annual energy yield per square metre is much higher for solar thermal collectors than for solar photovoltaic. Compared to PV, solar thermal collectors produce, on average, three times as many kilowatt-hours.  Source ... Cheers, Roger |
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Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 648 |
Quite right with your last comment Roger, solar heat energy is much easier to recover than electrical energy is through solar photovoltaic cells. Its just a matter of collecting solar radiated energy via absorption and then move it along to where its required by convection. Davo, just a reminder, even the best commercial solar panels on the market today are just around the 25% efficiency mark. So your solar panel sq meter energy calculations above are way off the mark. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Is very sad about the demise of your fan. Although you could put the Commodore centrifugal rotor back onto the motor and fabricate a simple box housing for it. No doubt there will be some other surprises along the way, both good and bad, but its all very interesting and well worth the trouble. I think the next step forward might be that differential temperature controller. One sensor in the room, another in the hot manifold. The blower may cycle, but from what you have said, the thermal time constant of the tubes is in the order of many minutes to heat up and cool down so cycling on and off may be fairly slow. Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Yes but I was calculating on heat value not electrical. I did add in the electrical as a side benefit. Far as I can see, panels are much like a co-gen set up on an engine. It's actually the heat that's the main output, the electrical is a side benefit but adds to the overall efficiency. From comments way back and other things I have read, I was of the belief that they should harvest 1000W M2 in THERMAL energy if that is what is actually falling on them which is required to give their Full electrical output. I know that is rare and as I pointed out, not going to happen in winter, but from the calculations I found, a 400W panel should be doing something around 800W in heat and only 160W in electrical. ( I went conservative and real world saying 100W earlier) . Although the electrical sounds low, that's what it calculated out at unless I missed something again. If there is only 400 instead of 1000W falling on the panel, that's a 60 % fall off plus whatever inefficiency in the panel, 100W is probably close to the mark maybe with a built in pleasant surprise if one got 120W. If that's not right far as the thermal generation, can someone link me to some info that would allow me to calculate the amount of HEAT they should generate please? Far as I can see they are just a Flat collector with little difference to any other thermal solar collector so until enlightened, I can't see why they wouldn't do much the same heat output as any other thermal solar setup. I was looking at the little portable AC units last night on Gumtree etc. I think I'm going to get one of those and give it a try. They seem to be around 3X the efficiency of the electrical Input so may be a lot more efficient than running either the big ducted which heats more than I need and is pretty thirsty or the little fan heaters for a room. The Ducted is also 3 phase and I only have solar on 2 phases so costs there and even that 3rd of the power adds up significantly. It also struggles here in summer so having an additional unit or 3 would be a great help in summer when I don't really care about how much power is being used anyway. I saw many of them are Cooling only but also thought of a recent comment about putting a window unit in backwards. These things are Ducted through a window so If I got a Cooling only unit, I was thinking could put it out on the verandah and just Duct the what will be Hot exhaust inside. Only problem would be when the outside temp falls below the thermostat setting and the thing wouldn't want to cool any more. Bugger! Was thinking I might also be able to direct the exhaust air from the diesel burner towards the AC unit which would utilise that Kw of otherwise wasted energy. Window Types normally have a Recirc or fresh setting so if the portables Recirc I could do that without brining in the exhaust Fumes. Looks like I'll have to find a Reverse one. Seems to be an amount of them although not as poopular as the cool only so I'll see what I can find and give it a go. No shortage of these things for sale though.... which may be a worry in itself. Think I have also come up with a design for a Veg oil Burner. Only question is now do I make it water or air heat transfer? Obviously air will be easier but Mindful of what Tony said about hot Metal smell and there is no storage ability... although not sure how Important that is atm. Spose If I start with air I can always change it over to water later on if I need just by welding in smaller ports. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
That was what I was wary of and why I questioned the value of using 2 panels to get what was possibly an insignificant amount of heat. A single panel is as you saw getting dragged down in lower sunlight and even when the light is pretty good so you can have a mismatch in voltages and get away with it. When you have grossly more solar output than load, the voltage will push up to that of the panel output, in this case probably around 37V. rather than the Inlines, I wonder if you just used a car Radiator fan and put it in a Box, ( adding in some simple stators would probably help a LOT) and then just an output in the back and feed that through the system. The radiator fans move a lot of air and would probably do enough pressure. See how the cabin blower goes but maybe If you want 2 panels, Put a voltage converter on the thing to limit the voltage but I think that's going to kill the scaling effect of output to sun radiation and it will get to max output pretty quick and stay there. Single panel and Pulsed capacitor output may be the way to go with this so you can extend the low end output a bit. Going bigger on panel input I think will really kill the whole scaling idea. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Just reminded how poor solar is in winter. Finished the 2.7 Ground mount array which is pretty well optimised for tilt and direction and not quite getting 1.6 Kw out of it. Checked other arrays and started wondering what was wrong with them? Nothing other than it's winter. The time of the year when brute force solar still just isn't enough no matter how much you throw at the problem. Feeling the back of the panels, I'm struggling to see how there is 4-500w of heat there as should be conservative for 1.6 Sqm of area @ 400W Sqm. Might be worth while If I could enclose the back of each set of 5 panels on a day like today but big job to do that. Sun angle is so low. Anything a meter in front and more than 300MM tall causes shading. Next job, the east verandah roof. Don't want to think about the 7 panels and the Kw I might get out of that for my troubles. :0) |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Roger, Inspired by your work and great reporting, I tired the same method with a PV panels and Started a new thread so as not to derail yours with my much poorer testing. Have to say I feel like it's a case of humble pie with the doubts I had. The results were not at all what I expected and I can well see why you have been so enthusiastic about this. It would be interesting for you to try something similar with your better measuring capabilities and see how it compares. |
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| Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 648 |
Hi Roger, I just received the Elitech RC-5 logger and got it to log successfully, showing the graph on the computer screen. Which of the 4 options of file saving do you use to show the graph on these pages? I'm, not very computer savvy. Thanks |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I went out about 5 Pm this afternoon with the sun well behind the clouds and at the start of the twilight to bring in my Panel I was testing the heat output with. Supposed to be gloomy and wet tomorrow ( of course, just when I have a new experiment to play with!) so rather than ruin the cardboard backing, I brought the arrangement in under cover. As yet another surprise with this, The fan was running. The air was certainly cold but I was amazed the fan was powered at all. wasn't turning too fast but it was certainly running enough that I noticed it by the cold air on my hand when I went to pick the panel up. I suspected the converter may have had something to do with it so I disconnected and then reconnected it and the thing started fine and went back to it's slow rotation but positive output. To confirm my theory, I took the converter out of circuit and direct connected the blower to the panel. Not a sign of life. Not even a tiny little spark when flicking the wires. Put the converter back in circuit and away it went again. It was quite dark with the sun behind thick clouds as well as I suspected just above the horizon and carrying the panel down under cover, I noticed The GTI's on my westerly ( as well as the Northerly) arrays had dropped out... as overclocked as the westerly one in particular is. They weren't making enough power with all those panels in that light to keep the inverter going but that single panel on the converter was driving the fan. It seems the converters may be well more viable than I thought for your setup Roger. Seems they will follow the suns output quite well and as your tubes seem to generate heat when they see light virtually, the converter seems to allow the fan to run where they wouldn't otherwise. I appreciate your fan will be a lot more powerful than this one but a converter may solve the problem of overpowering with 2 panels if that's what you need. As my fan was running when there was no heat to be had at all, the converter may make your fan/ panel combination a lot closer to what you want to match the heat output of your Tubes. If it is a bit delayed in the morning, that's probably a good thing anyway. In the evening I suspect it will slow enough so as the fan won't blow cold air as the tubes should be ahead in efficiency. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
I was surprised when I first read it and didn't really take any notice ... but after my experiences so far, when I read it again it jumped out at me. In the back of my mind I kinda thought the reason we don't read about solar air heaters is because they are a bit lame and don't really work very well ... but there are plenty of people aound singing their praises when you do look hard enough. Thanks for the condolences Tony, kinda serves me right. I should have known that a good burst of sun would likely be too much ... but I had decided yesterday was just one of those poor solar days and didn't think any more about it. Today I was going to be away and because of the forecast cloud and rain I said to my wife there was no point turning it on ... and I stoked up the fire before I left. Later in the day though, the sun was brilliant for several worthwhile periods ... so I need to stop writing off a day just because of the forecast or a gloomy start. And you are right, a differential controller would be a good start to getting this thing under automatic control. After yesterdays results with the temp sensor inside the evac tube ... I think that is going to be the place to identify just how much heat is available ... and when to turn it on. I am keen to datalog the temperature inside a tube for a few days and compare it with both the temperature in the sun and the hot air output temperature. I had initially thought the temperature inside the hot manifold would be helpful ... but it is usually just a degree or two higher than the output reading ... so not really useful. Yes, you did warn me ... just like me not to think it through. Exactly what did happen I think. I think if I had left it at one panel, it might have missed a few patches of mild sun ... but would have been a lot less chance of it going ballistic. I have been thinking that even though it might look like a backward step ... that if I can work out a system of control that works consistantly and well using the AC inline fans ... then I can apply that to a DC fan running off a panel or two ... and look into the voltage converter idea as well.. Thanks Dave and good on you for being prepared to do some experiments to find out if theory lines up with experimental data. I was with family today and caught up with a nephew who has almost finished his thesis about a particular scientific process or method. I asked if any of his writeup is backed by any experiments or practical work he has done ... but apparently not. I never went to Uni so I have no idea how it all works ... and it's no slight on my nephew, he's a brilliant kid and a real genius ... but theory only gets you so far ... then you gotta build something to prove your ideas. Well don't feel bad on my account ... I need to be challenged regularly and reminded of how things work ... like what might happen with too may solar panels on a 12 v motor!!! Haha, thanks for the vote of confidence, but I have just been blundering my way through trying out stuff as I go and (sometimes) listening to advice in here. It certainly sounds like a worthwhile direction to take, so I'll keep it in the back of my mind for now. Hi Klaus, pleased to hear you've received it. I don't recall making a choice on file type to save ... and I can't find it in the settings or parameters pages. It might have been a one time setting ... and I just chose the default one perhaps. When I plug in the logger (with the program open) ... it automatically downloads the data over 5-10 seconds ... and once downloaded I just click 'Graph' at the top to see the chart. If I want to compare a couple different graphs ... click 'History' and then highlight the files I want and then click 'View Details' over on the right hand side. Sounds intriuging Dave. Do you have a link for these converters so I can get a better idea of what they do please. I have to come over and read up on what you're doing ... sounds exciting. Cheers, Roger |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Pretty sure I linked to these some where before but that's the problem with informative threads! :0) This is the converter I have. Been using it on the inverter fan as well to stop that howling so much but never took much notice of how it followed the suns output. Time it slowed down the inverter was doing Minimal power anyway so wasn't an issue. Runs good and hard otherwise though. They are listed as 24V But some of the specs have them as 40V max Input. I have run them for couple of months above 30V and no problem so far. They do get a little warm, maybe hot but I put mine under the fan on the inverter so it's kept cool...ish. 40o day and nothing is cool, fan forced or not. You could put yours near the intake of the fan and gain another 1-2w heating. :0) |
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| Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 648 |
I use these converters in my caravan to get 12V from the 24Vnom lithium battery bank. So far there has been no problem whatsoever with them. They come in all sorts of configurations, I have one here that does 12V in to 24v out. Used that one to power a 18V battery drill from the car to drive a boat loader winch. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
There are Buck converters, boost converters and buck and boost. Different voltages and apperages but most of the Board types I have used are typically Chineeesse in that their rating are completely Bogus and nothing like stated. %0% is about as far as I push them. These metal cased ones seem the heavy hitters. I have never measured the load I have put on mine, I suspect I have never put 20A on it but I try to get these things over rated on purpose so they are under stressed.... or at their try output at least. That's pretty clever and I imagine that definitely would be putting the converter to the test with that sort of load. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
My apologies for having been AWOL. We've had a bereavement with an aunt passing away and things have been pretty hectic here. About the only thing I've done here apart from taking a few readings still ... is to have raised the whole array by placing a heap of pavers under each leg. Has got it more into the sun and is definitely making a difference. Under very similar conditions, on Sat morning at 9:30 the temperature inside the tubes before I turned on the fan was 41 degrees. This morning at 9:00, the temp was 93 degrees. Makes a big difference having only a couple inches of shade rather than a couple feet.  Cheers, Roger |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Sorry to hear of your Family loss Roger. Been down that road FAR too many times and only too well know all the ship that goes with it. Hope it's as easy as a situation like that can be for you and yours. Prime situation for a bad thing to turn into a nightmare but I hope you manage to get out of it as easy as hardship of it can be. Secondly, a hex or curse or pox on you my friend. I am watching FAR too many solar heating Vids!! It's not my thing, I am the guy burning oil, making fire and flames and being all politicly and environmentally incorrect ( as stupid as the accusations I have got for someone burning VEG oil) Not the sunshine and rainbows passive guy! Solar PV is one thing but this..... How the hell am I going to scare anyone with something as tame and quiet and non threatening as a SOLAR heater? Nope, this is just a passing brain fade. I'll fire up a 600Kw veg burner this week and scare the neighbours with it's literal jet like roar just to show I haven't lost the plot completely... yet! Don't know if you have shown the whole setup like that or I missed it or more likely my fast declining cognitive abilities have once again allowed me to enjoy something new for a second ( or 5th) time. That looks a REALLY good setup mate. I think the stacks of pavers in some way add to it. Look at that clever Spring mounting design for the fan. Provides spacing, reduces vibration and noise and made from on hand waste materials. Brilliant! That's a busy wall you have going there. My south wall is a bit the same and Mrs wants to move the water heater there as well to make the back west wall totally clear. I suggested that when we first got here and was Poo poo'ed. Guess it's not the suggestion but whom comes up with it that counts. 30 years of marriage next year, you think I'd have worked it out by now wouldn't you? Spose I'll have to buy her flowers or something for that one. Probably be spoiled and expect them every year then! Maybe I'll just give my Daughter money to bring home takeaway and call it good? I was sitting here this morning and Looked out at my ground mount array and saw the dew running off it and the sun gradualy creeping across out of the shadow of the sun and onto the panels. I then noticed some movement and saw it was steam rising up off the panels. Well there is your solar heating demonstration right there. I spose in reality its a bad thing, heat going forward instead of back but whatever heat is a bonus and once again I am reminded, cheaper and easier to forget the losses than try and make the setup more efficient. We were again Discussing putting a verandah across the back west wall for aesthetics and to keep the summer heat off. I mentioned Instead of a roof we could put panels and I could set them up for air heating. I quickly pointed out they could need a backing so we could have the plaster like finish insulating material she saw a while back at stratco and I'd just need to put some drain pipe as ducting which could also be enclosed. Said she's not worried what's on top as long as it looks neat underneath. Winner! That's a good 8M wide stretch and plenty of room for 2M long 400W panels. Think there is still 7 of them up the back so all good. The rest of the width can be some corrugated roofing. I may not even need to back the panels. If I have them on the beams on the top and then put the ceiling material/insulation on the bottom, the pace in between will be the hot air plenum itself. Duct the hot air up through the eves, into the ceiling and back into the house. just need a shut off damper or Diverter for summer. Would be good to really put something like this to work in a practical and aesthetically pleasing situation. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Thanks Dave, appreciate that. She was 94 and ready to go, and wanted to go. Makes it much easier to handle. Haha, serve you right ... you've got me watching gung ho oil burning videos and feeling totally inadequate. And yeah, solar air heaters are a bit girly, but at least the neighbours shouldn't be complaining about the noise and the fear of it all blowing up ... though you never know with some neighbours I suppose. I think most of the photos have been from the front so haven't shown the whole assembly ... so you're not losing it. I should have thought to post a shot like that earlier. I got five of those stands with my tubes, or variations of it. I'm really proud of my motor suspension device ... thinking of patenting it. My duct tape is a bit old and in the sun it slowly slides off, so the closest thing I had within reach was that offcut of pvc. Has worked a treat, so I've left it there. Haha, that sounds familiar. And fortunately that area is hidden and least travelled, so probably best to have it all in the one spot. Yeah well good luck with that. I see you like living dangerously. Yep, sounds like you have permission to me. I haven't seen any solar air heaters built into a roof structure, but no reason why it wouldn't work. Sounds like a great idea and gives you lots of scope starting from scratch. Make a great basis for your next youtube series too. Absolutely. The more I think of it the more I like it. Most of the building material people have various products for simply assembling verandahs and patios etc ... they could just as easily supply panels that connect together to form a solar air heater ... but which also doubles as a roof. Cheers, Roger |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I love looking at these Money saving, energy efficient, solar powered etc ideas but they all have one big drawback, it's incorporating them around your home without making it look like a junk yard. The vid I watched yesterday where the guy put can heaters on his hangar wall flush up against it was great. If anything it looked like a decorative feature. Sure, It was a tin walled shed but would have looked GOOD on a house. My North wall is 2/4 Covered with hedge and it's going to stay that way because the shading benefit in summer would vastly out do the heating benefit in winter. I thought about making heaters on stands that would be put round there for winter but there are no windows to duct the air through only doors so that is another complication and drawback to the idea. I am wondering why more things like solar heaters aren't done commercially? With panels, if an extrusion was made to go round the panels, they could slide into it, there could be a place for the backing to be attached, there could be provision on the extrusion to fit onto standard racking and probably some standard AC fittings and flanges made to connect it all up. It could not add much at all to the price of a solar setup, probably be retro fitted and would be a huge selling point in the increased efficiency and versatility of a system. So I'm left wondering why this isn't done even here in Oz? Being the pessimist I am, I wonder if it's something to do with the power and gas cos having an influence somewhere or other vested interests Kyboshing it? It's too damn simple and easy for someone not to have thought of it especially when you have organisations like the CSIRO and these days, all sorts of gubbermint grants and crowdfundng fortunes are thrown at anything environmental. If I had any incentive and motivation left in me, it's something I would put some time and effort looking into. There would have to be a market in it and when you have ridiculous flawed ideas like solar roads and other stupidity coming up all the time and fortunes thrown at that time and time again despite repeated failures, no way there couldn't be something in this. I don't think it would have to be a set the world on fire proposition, Even if it could be shown you could double the savings from a solar installation, that would have to be a HUGE selling point and like the rest of the system, it would be an ongoing yearly saving. Even if the install price doubled the system price, I may halve the payback time so no different in ROI. The fact that PV generation is so much lower in winter and this would offset it would make a big difference to the economics I believe. Was talking to a friend last night. He suggested I do a solar Channel. Hard to think how to make it entertaining but at least I could make it realistic. The pedantic Crap I see so many go on with on different solar channels is pretty laughable and it's clear many rely more on what they have read than hands on experience. I think a smart person with some engineering and maybe building experience would have this nutted out in no time. I have had the idea of just using panels for a roof for some time and I see there are some few people doing it, mainly DIY and over seas but the commercial companies are far and few between. For sealing and joining the panels, all I can see would be needed would be something like T shaped insert that went between and over the top edge of the panels. Have it made of hollow plastic extrusion so it had some ability to allow the panels to expand and contract and that's it. Could not be hard to make system components to do this. Edited 2021-06-08 16:03 by Davo99 |
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