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Forum Index : Solar : Deciding if I should build this solar heater
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rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 01:54pm 11 Jun 2021
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Probably not sexy enough ... though one big drawback is that they simply are not 'reliable' for the likes of Joe Public or probably more likely, Mrs Joe Public.
And not unreliable in the sense that they break down, but unreliable in their consistancy of output ... pretty much the same as pv solar and wind!
I'm sure a system could be designed to incorporate solar panels into a roofing assembly to make it easy and economical to use. The concept is certainly simple enough.
I guess it needs a few things first ... for someone to work out if it's really worthwhile to do ... and then for them to believe in it enough to design and build it ... and then for a hard up ex cricketer or footballer to hawk it to the rest of us.
Nah! I don't think so.
And maybe it's because it is too simple ... no new technology to invent and sell ... just cobble together some old school solar panels, some fans and throw them in some enclosures.
You have a point there. Some of the things they come up with are simply crazy.
Great idea. You're too hard on yourself ... you can be funny and entertaining without even trying. Just tell it the way you see it ... and do what you did with the oil burner thing ... lots of experiments and show different setups. Your solar run fans would be a great topic ... and using excess solar to heat water for greenhouse heating or weed killing etc etc.
Yeah, I've seen your comments about this in the past ... time to throw something together. Especially seeing you have a use for a verandah ... perfect reason to do some experimenting. Make a great youtube video as well. Cheers, Roger
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 02:40pm 11 Jun 2021
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I've been a bit quiet here lately ... got behind with my paying work by spending too much time playing ... and had to knuckle down for a bit to try and catch up.
Had a fun experience today when I came in for luch. The unit had been off for the morning coz it was pretty dark and grey ... though by lunchtime was improving.
I switched on the fan and was instantly hit with a blast of hot air. Over a couple of minutes it climbed to 73 degrees ... and then took five minutes to drop to 60.
At the 14 minute mark it was at 46 ... then floated around 38-39 for another 25 mins or so because the sun came out. Then slowly dropped to 25 ... so I turned it off otherwise I'd have got back into my work and forgotten about it ... and then pumped the place full of cold air.
I really need to fit some auto controls ... but still trying to decide how to go about it.
I had thought it needed a variable speed motor to follow the available heat ... but after a few experiments of turning it off completely ... waiting for the heat to build up ... then running the fan flat out to pump all that heat in before it drops too low ... then off and repeat.
The jury's still out on that one.
And finally I should admit that I've committed to build a full scale version to go on the roof. This baby's going to have sixty tubes and will be exactly 4 meters wide by 2.4 high. I'll weld up the frame and dry assemble it in the workshop ... then drag it on the roof ... and reassemble the rest of it up there.
Managed to create a shopping list of material for the frame and got to the steel yard in time before they shut. Only hiccup was that they could cut down the angle and square tubing to size to fit my 7x4 trailer ... but they won't cut C-Section. Reckon it catches and tears the teeth off their saw!!! (this is a big steel supply place here in town)
They were kind enough to forklift an 8 meter length out onto the footpath for me ... so just as well I'd thrown in my battery angle grinder with cutting blade ... and visor too! Got it all home safely. They don't want customers cutting up steel on their property in case of accidents and of course insurance!
As I mentioned in a recent post of a bereavement, I spent a lot of time in the car over a few days ... and I kinda designed the new version in my head. Only last night I put it all down on paper, so we'll see how it goes.
Top image looks a bit like a combine harvestor.
And the hardest part at the moment is working out how I'm going to go from my rectangular ducts to a 10 inch round outlet.
Cheers, Roger
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 09:34pm 11 Jun 2021
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For the middle duct, you can buy both plastic and sheet metal cable ducting that has a removable lid. Available in a variety of sizes and very easy to work with.
Edited 2021-06-12 07:38 by WarpspeedCheers, Tony.
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578
Posted: 11:58pm 11 Jun 2021
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The design is very clever Roger. You should have a lot of heat going through there. From what I can see you have wisely made the centre the hot air but I don't know if it's worth insulating the outer casing as well? I spose any heat transmission ends up in the same place in the end. Maybe you should paint it black to try and pick up another degree of heat and increase the surface area by that much. :0)
The rectangular to round fitting shouldn't be hard to get at an AC suppliers. I have seen them. Depends what the sizes are as to if they have them as a fitting but they do make custom still all the time. Been with and to pick up stuff for my mate. They can knock it up pretty quick as well as it's everyday work for them.
I had a like a half plenum made years ago so I could cut a slot in the ceiling and recess a paper holder up there. Was going to box it in with gyprock by mate said get this made and then just put it up there and paint it. Came up really well and was cheaper and a heck of a lot easier than doing the gyprock.
There is a Plastic Duct brand my mate uses called " Aussieduct". If My mate uses it, must be good. It's actually called " Trunking" generically and is mainly used for cabling and pipe cover. The AC profile would probably be a bit small for what you want at only 100MM but there is another one that's 150x 75 which may flow a bit more air which I think you'll need with so many tubes.
The weather here has been abysmal for solar. Cloudy and wet all day and down to a sub zero Night. Back to Jugs of warm water on the car windows because the wipers won't get the ice off. Last 2 days didn't make it to double figures. Little diesel couldn't keep up so I ran the AC briefly here and there and didn't take long to get the place up to temp and cut out on the thermostat.
Times like this you definitely need a backup heat source.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 12:35am 12 Jun 2021
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Haha, now you tell me. Thanks for that info Tony ... if I'd have known about it I certainly would have considered them.
I had frequented the local salvage yards looking for something to use, but knowing I want to braze the aluminium tubes onto or into it ... there weren't too many options.
What I settled on was to use two lengths of aluminium angle and braze the tubing directly into holes cut in that. Then use them as the backbones of the duct, with a flat sheet joining them at the bottom and a cover bent up for the top.
Mmmm ... I'm not sure if I do have it right or not, but the plan is to have the cool air blow in through that central duct and straight down through the ally tubes and back up inside the evac tubes bringing the heat with it.
Then the hot air is forced into the outer space, which is insulated ... and out the other end.
Some of that heat is going to be lost/absorbed by the central duct carrying cold air ... but it is also preheating the cold air ... so I didn't think it was worthwhile insulating the two. Besides each lot of insulation bites into the duct volume and I wanted to keep that as small as possible.
That's very handy to know, thanks Dave. I had given up on the aircon guys because I couldn't even buy simple duct fittings from our local suppliers. Looks like I'll need to make some calls and go to Adelaide probably.
Ours has had some ups and downs ... but I'm still amazed at how often the sun does still pop out and just how much heat I can extract during those times.
Of course without the wood fire I'd be in trouble ... but already the reduction in wood useage is well worthwhile.
Ouch! Hasn't been anywhere near that bad here yet ... though they did say we had the coldest minimum temp ever recorded here for one day in May.
I think that in the month or so of running this thing, there's only been about 4 days when it was not worthwhile turning it on. The rest of the time there have been at least a few hours each day, right up to maybe 6 or 7 hours of decent heat.
Yes, most definitely. Love our wood heater, despite the work.Cheers, Roger
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578
Posted: 12:41am 12 Jun 2021
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I am loosing count of how many comments I have read and continue to read in different solar forums of people complaining because they had a power outage and the solar wasn't suppling the place and they think there is either something wrong with it or pissed off they weren't told it wouldn't work when the grid was down.
I would well Imagine people bitching because they turned the solar heat on at 10Pm and it didn't work. Never cease to be astounded at the money people will spend without doing one bit of homework or research as to what they are buying.
Made me laugh because the sarcasm is spot on with reality. A mate that was putting on solar before Christmas had a hard time believing that a famous Cricketer would promote a company that was about the most shoddy in the solar Business. Took a bit to convince him looking up reviews etc before he took my word for it.
Maybe I could get one of those Bimbo celebrities that are only famous for being famous and have no other discernable accomplishments or done anything of merit ( unless you count a Sex tape) to promote it? Probably have their Brainless followers whom don't even own a home signing up for it. Alternatively, Just put it on facetwitgramchat and pay an Indian company to give the accounts a Millions likes and I'll be able to sell Ship sandwiches without the bread.... Hmm, why bother developing a product when you COULD do that?
Now THAT I would take as a Highly Plausible Reason. But there is a way around it I think..... I'll Just buy all the old Circuit boards off Tony and other guys here that are no good and do some flashy Pictures of " The latest technology in computer controlled thermal management Microprocessing" and put an old board in a case with every install.
Won't that Bugger the Chineeese when they go to rip off the idea and try to reverse engineer it?
I have hit a snag before the rush of blood to the head even got out of control. The Mrs being too clever for my good, Immediately picked up when I showed her the plans for the verandah, asked where the transparent panels were for skylights and were they going to do every other panel as she didn't want that side of the house being dark.
Errrr,,,, ummmmm,,,, ahhh...... I said for that width didn't need it as there would be plenty of light coming under the roof. She didn't buy that for a second although I think it's true. Of course when I said I want to put panels right along there...... I could hear the cartoon sound effect of skidding tyres in my head.....
BUT.... looking at that wall, there is only the ensuite window which I want shaded to keep the heat out and as much time as not, probably more, we use it at night anyway. There is my my cave...errr, office which I have a canvas shade down over all the time as I have been accused of being a Night owl all my life and am happier in the dark than the light and the daughters bathroom which she has the heat lamps on any time she is in there. The other ones are the Toilet and Laundry which are tiny little windows anyway.
I told her all the rooms have lights and if she wants, I'll put in an LED which will be permanently on when the sun is out like in the kitchen so when the sun is out, the rooms are lit..... Better than they would be now probably. Works well in the Kitchen. Having a 250W Panel driving a couple of 12W lights mean they work even on cloudy days and make it brighter than it would be with the skylight she wanted and I didn't.
Spose I could put a couple of LED strips right along under there run off a panel or 2 to simulate the daylight. Will need some lighting anyway.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 01:18am 12 Jun 2021
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Should be o/k. In summer the verandah will shade, and offer some welcome relief from excessive glare. In winter the sun will be much lower in the sky, and even on gloomy days, still plenty of light.Cheers, Tony.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 02:46pm 13 Jun 2021
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Yes, agreed. In fact it would be very common I'm sure, even though common sense would tell them what to expect.
I read a meme yesterday with words to the effect ... "50 years ago our car owners manual told us how to adjust the valves ... todays manuals have to tell us not to drink the contents of the battery!"
I've been reminded occasionally that sarcasm is the lowest form of wit ... but I don't really know any other way to deal with some situations.
Yeah, yeah ... as long as you make it one with really bulbous lips .. they'd have to be the most convincing and believable as to knowing what they're talking about. NOT!!!
That's a shame. Still, you're only just starting. You'll work out a counter argument for sure
Amazing what they can come up with if they don't like an idea. Now it's your job to work out what the real reason is.
We have the same trouble here with a couple spots in the house, especially the kitchen. My wife often mentions a skylight, but when I looked at the work involved I came to the same conclusion as you ... though of course I've only thought about it and not followed through.
See, there you are, Tony has the answer for her right there.
Now all you have to do is somehow make her think it's her idea ... mmm!
Well, we have one day left for our long weekend and I still haven't even unloaded the trailer. But I did make awesome progress in cleaning up the shed and organising space to build this thing. I should have done that years ago when we first got here, but waste too much time online instead of doing stuff.Cheers, Roger
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578
Posted: 11:26pm 13 Jun 2021
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When I bought my Tractor, The amount of safety Notices outdoes the actual instruction Manual about 3:1. The guy gave me a saftey induction that took over 30 Min and had a list of the points he had to address. Clearly people have come up with ways of hurting themselves and stupidity I couldn't think of if I tried. When Dad got his new Tractor was the same thing only the safety induction ( with a little operation instruction: here is where the fuel goes, do not Urinate in it or try to run the machine on Paint stripper) took a solid hour.
Much of it is Government Mandated both of the guys said. Takes a bit of digging to find what the Tyre pressures should be or how much oil they take but lots of warnings not to stop the thing on a 45o hill and walk in front of it without the brake on or don't defeat the safety lockout and put your feet under the mower deck while it's turning.
I looked up Skylights and they were expensive and prone to leaking and said to be one of the biggest causes of problems in a house. My father has one in his Kitchen and despite about 5 Builders and as many hacker like me getting on and in the roof trying to seal it up, still leaks.
I just used a panel on the verandah in an out the way spot to the rest of the arrays and hard wired it to a couple of LED's. Wiring goes under the tin so no roof penetration and they come on even on the darkest days. When they go out you can't see where you are going anywhere else in the house so work perfect. Cheap, easy, convenient, no potential problems. I bought a box of the lights and have them elsewhere in the house and they cost me $9 ea with the transformer. If they burn out, I'll just replace them.
He usually does have the answer and it was a very Valid point. I think she is wary because the Verandah at the other end of the house makes the Kitchen dark even though half the roof is transparent. By the same token I have already provided the answer to that so not sure what the objection is. main Verandah is going to be less light when I'm done because I'm planning panels over that side where the transparency's are as well. This new bit will only be 1/3rd as wide so should let good light in anyway. Main rooms it will affect are the cave that has the canvas Blind over it now and the daughters bathroom that is 90% used early morning and at night.
Both bathrooms have Highpower LEDS around the Mirror as well as in the ceiling so they can see to put on their war paint. They have them on when ever they are in there anyway so we could have a Night 30 Days long and it still wouldn't affect them.
Again, the sarcasm is right on the Money. Doesn't seem like a low form of wit to me when it accurately and succinctly provides the key solution to a significant problem. And provides a laugh as well.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 12:46pm 14 Jun 2021
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Yes, I can believe that. And the government seems to be advised by totally inept people who need to make themselves appear useful, so they just dream up all this crap and dump it on everybody else.
Yes, 100% correct. All the important and useful stuff is buried in between all the other rubbish.
The woman across the road from our old place went to visit a friend and ran up to give him a hug ... except his ride on mower blades were still spinning ...
Meanwhile after multiple surgeries and skin grafts she's still in a lot of trouble.
Short of him leaping off and tackling her head on before she got that close, I don't know what else he could have done. I know our mower takes some time to wind down even after you throw it out of gear.
I have to do that here. Like you said, a single panel on the patio roof alongside would be perfect for it.
I recently replaced a circular fluro with a similar shaped led fitting in the kitchen and the improvement was marked. I just need to find the right fitting to fit between that light, four downlights, three other lights, three aircon vents and a flipping ceiling fan. It's a huge area, but the ceiling is busier than Bondi Junction.
Yeah, I get a laugh out of it often, though it's not something that's appreciated here at home ... so I just resort to it on the internet with like minded individuals. Cheers, Roger
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 03:05pm 14 Jun 2021
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I bought a supposed datalogger multimeter ... an Owon BT41T, which I have been using to monitor various temperatures etc ... but it's really a crap system as far as I can work out. Actually thoroughly disgusted in it to be honest.
The data recording works via bluetooth to a suitable device ... eg a mobile phone ... but of course as soon as the phone goes out of range or there's a hiccup ... the recording stops and unless you're on the ball the whole effort is wasted.
Being a holiday today, I left my phone alongside the meter for the day so finally got some worthwhile readings ... but then it's a major pain to extract anything from that data.
I finally just screenshot the crude graph the phone shows and photoshopped it into my normal system just to highlight how hot it gets inside these tubes.
I do have a question if any of you boffins know ... what program can I use to graph my figures. They are presented in excel ... but I could not make that show a graph ... too many data points I think.
Cheers, Roger
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 03:01am 20 Jun 2021
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I've given up on the data logger side of the Owon meter for the time being.
I ended up doing what Klaus suggested and modified one of my Elitech loggers by removing the temperature sensor off the board and fitting it to the end of a longer lead so I could get it down into an evacuated tube.
The temperatures I get from down inside the tubes are now within a few degrees of what comes out the outlet.
Before, they seemed to be around 10 degrees higher using the Owon and its temp probe.
When I removed the probe, the fibreglass sleeving has started to show signs of browning already (after about a week) ... so must be pretty hostile inside the tubes.
I need to post a few charts showing the new comparisons ... but in the meantime ...
Cheers, Roger
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578
Posted: 05:52am 20 Jun 2021
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I enjoy keeping up with the latest instalments of hour Heater Roger. Very good also you can put some numbers on the output I can relate to and have an understanding of.
If your low atm is 1200W, That is going to be significant heating when you do build the full size version and will definitely make an appreciable difference to the temp of your home.
I have been keeping mine around 19-20 this last week and I check the wall, floor and furniture temps. They tend to be very stable and might drop to about 18 in the mornings as I usually turn the heater down at night just to keep the chill off but it's not like I'm trying to get a 10o or more temp rise. I do find it is pretty easy to get those couple of degrees.
With the power you will have available, I can see that having some storage will be needed to make full use of it. Here sunnd days will maintain temps but as soon as that sun goes ( and well before actually) the temps will drop and fast. I think with 3+ kilo on tap you will quickly get the house warm as you want it though the day and probably pretty early on. Would be a shame to have to switch it off so if you could put the heat to use it would be good.
You should be able to make a LOT of power that shoulder period coming into and out of winter and cut your wood heating by a good margin. If you could divert this energy to your pool in summer, You could boil the thing after a week. :0)
Have you done any more on the big setup construction?
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 01:48pm 20 Jun 2021
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Thanks Dave, and I appreciate the interest and encouragement. It's taken me a while to get comfortable with quoting my figures, but they are consistant and I am confident I'm not overstating my results.
Absolutely. That's what's been spurring me on so far because even this baby version makes a difference here on good days.
eg. the temperature in the lounge started this morning at 19.2 degrees ... and by mid afternoon was at 24.0 ... that's pretty close to 5 degrees gain ... and for me coming in from working in the shed, that's almost a bit too warm for my comfort.
Definitely not complaining though.
Ours is much the same through firing up the wood heater each evening ... and I feel a bit of a dill doing the rounds of all the thermometers in the place ... but I'm getting a pretty good feel for what is happening here.
Yeah, and I'm a bit embarrassed that I still haven't tried feeding the hot air in under a solar blanket to concentrate the heat onto/into the tiles.
And now that you're mentioning storage and after this mornings experience ... I can see that on a good day (like today) ... that after feeding in as much heat as we need ... I could turn it all off at say 2:30pm ... let the heat build up like it does ...
... and then at 5:30 as the cold kicks in on dark ... pump in the heat that has built up, before it dissipates overnight. Admittedly that would only buy us 10-15mins before it fades, so possibly not worth the effort. Have to try it.
Definitely. In the early days of my experimenting we had a few days of really poor conditions and I was having second thoughts ... but bad days are far outweighed by good days overall ... so definitely worth pursuing.
And there's no doubt we're saving on wood. I rarely feed the fire during the day anymore ... just evenings and overnight ... then nothing until the next evening.
Only time I do is if the forecast is bad and my wife will be home for the day ... and even then, the forecast is usually wrong and there's plenty of sun to kick things along.
Gulp! very little. I did order my 60x60x6mm aluminium angle which should be here Wednesday ... and I laid out the steel on the floor to get a feel for how it's all going to look.
I stalled over the weekend and made a trip to collect more shelves to finish what I started last weekend. Finished off the shelves and got more junk off the floor ... so now I have no excuses.
I do so little welding that everytime I do a project it takes me ages to get a decent weld ... and it's usually only when I'm nearly finished that the welds are starting to become presentable ... so I keep dragging my feet on starting.
I just need to knuckle down and do some practice first.Cheers, Roger
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 10:25pm 20 Jun 2021
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When this is in its final form with a differential temperature controller, and room thermostat, I think this is all going to work wonderfully well for you.Cheers, Tony.
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578
Posted: 01:49am 21 Jun 2021
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It will be good to see this and the numbers when it is finished. You should start a YT Channel and document your work Roger. it's something a lot of people would be interested in and could earn a few buck on the side for you. I find my old vids are becoming very handy. Stupid as it is, I am literally forgetting what I have already done. I search for some ideas on things and My own vids come up and I'm sitting there like a moron going " Oh, I already did that and worked it out" Yeah, nothing wrong with me at all!
Have to admit I'm having reservations with the solar heaters. We have had 3 weeks of mainly crap weather with only the occasional sunny day here and there. x10 on the output I would have got from having a whole array over the last week would still be less than I need for a day to keep the place comfortable through the day.
Last couple of days barely got into single figures and geez it made a difference. I cranked the little heater when the sun got low and by about 8 pm my daughter was turning it down and complaining it was too hot inside which I agreed with. Got out the thermo and we had the place hot enough to nearly peel the paint off the walls, 23!! Felt like 43.
This place is a disaster for heating and cooling with the endless glass. When it's cold you can go to a window and feel the cold air falling to the bottom. It's just an energy pit for heating and cooling. I am convinced that you can have all the insulation you like but without double glazed windows, it's like trying to keep a leaky bucket full of water.
I am in several minds about the heat under the blanket. I had the diesel heater blowing on the floor. Made a Nice very warm spot. Because the place has a slab, once the heater was directed else where there was little heat retention. I believe the warmth just got milked away. the energy would have still been in the floor or radiated, probably some into the ground which would go back to the floor still being less cold but it did nothing really to keep the floor warm or re radiate the warmth.
Will be interesting to see how your more concentrated experiments go and I'm sure you will get some real Data which is more than I did.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 02:49am 21 Jun 2021
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Bubble plastic over the glass lets the light in but will make a very big difference to heat transfer. Better ask the Boss first though..............Cheers, Tony.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 11:52am 21 Jun 2021
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Another great day today ... Five and a half hours of 30 and above ... and seven hours of 25 and above ... and all with the fan on top speed.
There was a frost this morning and when I turned on the heater at 9:08 this morning the ambient temperature was only 8.1 ... yet the tubes were up over 80 degrees C already.
Cheers, Roger
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852
Posted: 12:34pm 21 Jun 2021
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Thanks Tony, it does look promising. I just need to stay the course ... and there are still several months of cold weather in front of us, so definitely need it finished as soon as possible.
Haha, mmmm ... not sure about that. I suppose it should be of interest to some people, though the biggest drawback is the fact that evacuated tubes are not exactly cheap ...
Having said that, I'm sure there's plenty of them pulled out and just thrown away when people give up on them for their water heater.
Need to make friends with plumbers who install and maintain them ... then collect any bits when they pull them out.
Haha, sounds like me when I'm having trouble fixing a board and I finally solve it ... then I go to write some notes on it in case I see the fault again ... and I come across notes from where I've had the exact same fault before ... Arghhh!!
There have been times I was ready to give up ... and that's why I decided early on I was going to have to go big with the thing ... to give it a chance to actually do something.
I think that's why others who have tried tubes never went very far, because with just a handful of tubes the result is so poor that they give up.
Ours isn't so much the glass, but the fact we can't close anything off ... so the heat just disappears. Have to admit I've wondered about hanging big heavy curtains across the passage and the lounge entrances to keep the heat up where we spend most of our time ... but somehow I don't see that going down to well.
Out of interest, what temperature comes out of that heater? ... coz mine of course is down between 25-35 most of the time ... so even less likely to make a difference.
I haven't recorded the floor temperature much at all like I intended ... I really need to do it more often so I have a baseline to compare with when I try the blanket.
Because ours is on a slab too ... I expect the heat to just 'disappear' when I try it ... the question being whether it slowly increases the temperature of it over a week or so ... or not.
Yeah, I am a bit slap dash with some of my experiments ... but I've slowly worked out what to measure and look at, to arrive at some meaningful conclusions (I hope). Cheers, Roger
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578
Posted: 12:07am 22 Jun 2021
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Mate, Don't let that worry you! People spend 10's of thousands on all sorts of things like Commercial Home batteries, solar panels, underfloor and Geo thermal heating and so it goes. The 90% Audience will be American and they either get things at a fraction of the price that we do or a fortune more ( Solar panels For instance) and still get them.
I think this would be Extremely interesting to a lot of people. 2 things you have to do: Try to make it light hearted and Funny as well as Informative. Give the vid an interesting title and write a good description. Might also help if you do lots of measurements because believe me, there are people that would ask for measurements on a Video showing how to drive a nail into a bit of wood. I get asked for "Plans" all the time. I tell them now you have been looking at them. If you can't read them, don't build it.
There always seems to be surplus clearances in the US as well where people pick things up " For Cheap" as they say. You also have to remember, -IF- you make if entertaining so the people interested in doing it aren't bored Shipless, There will also be a large Audience that will watch for entertainment and general interest. I have watched endless Vids on things I will never build but oddly enough, I have watched Very Few Vids to do with solar installation because all the ones I watched were boring as hell and most of them were just wrong or full of pedantic clap trap.
I think for something like this there would be a growing market with what is going on in the world and even people in the US suffering power shortages like it's a 3rd world backward village in the sticks.
No Shame in doing that! You must come across hundreds of things that all look the same and if you do it every day... Bit different for me.
Not that For me, it's the amount of cloudy days that a setup of any scale is going to be useless. If I can't get any heat out of one or it's not in direct sunlight, the result will be the same X10. I can see it with my solar arrays the pitiful amount they are putting out some days as well. I looked yesterday and worked out my 3 inverters did less than half of what just one of those inverters will do most days in summer. And spring,,, and Autumn....
Find it in a home and Garden type magazine, point out how nice it looks and as I think it was you told me, make her think it was HER idea. I have noticed the women folk are distinctly NOT into saving energy or money around the house. seems easier and care free just to pay whatever bills... no matter how high, rather than do anything to save a buck.
Usually around 80o C.
There is a readout on the case/ heat exchanger temp and that goes from about 90 to 190 depending on the setting but the air on normal settings tends to be around 80. Can be a bit cooler if I set it Low and in Alpine mode which is a lean fuel setting and can be a bit more if I crank the thing. I also set the exhaust up in front of the intake so there is air being drawn from the exhaust pipe and across the little muffler that might make a degree or 2 difference. For the main middle setting I use, every time I have checked it's around 80 Though.
Unless one puts their hand or leg right up to the outlet, the heat tends to dissipate quickly though.
To make the slab increase in temp you would first have to be pumping more heat in than it's loosing. I expect that to be a significant amount. For a small house that has a 10x15M slab 150mm thick one would be looking at ballpark, 50 Tons of cement. Concrete is very roughly 1/4 the thermal mass of water ( hard to believe isn't it?) so that's about 12.5 ton thermal mass of water. To raise that amount of water ( with no losses) from 10o to 25 would require about 220KWH of heat input. Less than I would have guessed but I usually think in terms of water and On that I would have been close to the thought I had.
In practice I can see it easily being 2-3 Times that at least. You would have to heat the ground under the slab and you will have leeching going up the outer walls and then there is the floor radiating itself..... yeah, maybe 1000Kwh would be close to the mark.
However, as I have learned, there is ( in my feeble mind anyway) a difference between heating and stabilising. Even if you just stop the slab going to 5o, and never gets warmer or cooler than say the temp in autumn, then that's achieved something as far as comfort goes. I have never really heated the house above what it was when I started heating it and the ambient daytime temps of the great sunny days we were having and it's been so much more comfortable this winter. I am sure that is heating in a technical term but in my mind non technically, raising a temperature is heating, stabilising is something else.... and is much more doable on very limited power. I have gone the route of keeping the thermal mass warm this winter and I'm not sure if it saves any energy, I tend to think not, but the lack of the hot and cold swings is more than worth it.
If Ever I built a house, which I never will now, I would 200% have hydroponic tubes under an insulated slab. A thousand Kwh would be a walk in the park for an oil burner, I have them kicking out 600Kw without thinking about it but I would be practically limited to something like 200 Kw with an affordable ( used) heat exchanger. Even that is like 6 Hours allowing for warm up and the Comfort that would bring in having warm floors like that.... would be like living in paradise to me.
At my old house where we had floorboards, I Blew the output from a burner under there. The heat was wonderful but the fumes coming up and the fact I was pushing exhaust directly under there was not exactly safe nor something I did more than a few occasions. Was always going to set it up properly with a HE and pushing warm air under there with a radiator but we moved before I got that far.
I was at a friends mothers house a week ago looking to put solar on there. She has underfloor heating. OMG! Looking at the circuit board with the 3 phase individual 32A breakers and seeing the 6mm cable coming out the back of them into the circuits own contactor.... I thought the lights must go dim in the neighbourhood and the power meter spin like a turbine when this kicks in. The house is a BIG L shape as well so there is plenty of floor to heat and that wouldn't come up to speed in an hour.
Overall never seen a switchboard and power boxes ( yes 2 of them) on any private single dwelling home like that before. Said to mate this is going to be the best investment your mother ever made!... but anyway.
HA! You post numbers, I post "Felt warmer". I think we can tell pretty quick what is relevant and what is not. Doesn't really take much to know if something is working or not like this.
Sitting here now it's another lack luster overcast day. Can see the panel heater out there and I know it's doing nothing and I can't even hear the blower with the dodgy bearings vibrating. Not much solar action happening today and the rest of the week is going to be the same to worse. Won't make enough solar power to boil a kettle.
I'm going up the mountains to see my Doc now so I'm sure when I get back it's going to feel like a heat wave here in comparison.
Knew all that great weather we were having earlier would soon be made up for. :0(
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