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Forum Index : Other Stuff : Anyone do any real form of " alternative" heating or cooling?
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rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 792
Posted: 12:17pm 05 Apr 2021
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When you put it like that it's hard to argue with.
Wow, 80kWh a day ... that's a lotta juice.
We've got a huge north facing roof and plenty of east facing ... but minimal west. Still, I have to walk before I can run.
That multiplication factor of 2.4 was for winter in Sydney I assume. Where did you find those figures, that is very handy information ... what about the rest of the country?
I wasn't planning on fitting 25kW of panels ... maybe 15 ... but will give me a good excuse to aim for more. And I still expect I'll be running the wood heater for some time, so should be no real issue.Cheers, Roger
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577
Posted: 01:43pm 05 Apr 2021
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No Doubt that Solar powered AC is far and away the easiest, most efficient and most practical form of heating and Cooling... If you can generate the power.... and maybe to a good degree if you can't.
Yeah, sure is. That wasn't just the AC, was the water heating and everything else as we are ALL electric. The sewage system pulls about 3 Kwh a day on it's own. Lately without heating we have been doing around 20-22 KWh a day. I don't know how people get down to half that as some seem to. Maybe gas hot water and cooking but we are a long way off.
I don't think east or west makes that much difference as long as it's not shaded. Obviously east makes power in the morning and west in the afternoon but apart from that....
I am going to try some east panels on the verandah. Haven't put them there so far because the roofing is transparent and the Mrs Didn't want it to bee too dark. Not really sure it's going to make that much difference and as I can get 7 panels up there, , over 2Kw of 400's, I think it's worth it for winter. Already have them on the other side and they do well in the afternoon.
Yes, sorry, I wrote that poorly.
No idea now, maybe the solar quotes website? I was looking through that the other day so maybe there. The site I use for calculating outputs is:
https://pvwatts.nrel.gov/index.php
You can put in YOUR particular Data and I have found the estimations amazingly accurate. Putting in the numbers for ideal tilt and orientation, I get around 2.9x for winter and only about 5 for Summer. That was varying roof angle and looking at lowest and highest months not an average so also some flexibility there. It would of course depend on your roof pitch, orientation etc. I would say though that 2.5-3 x would be close to the money but also, depends on the amount of over clocking on your panels.
I had 6.2 Kw of North facing panels on a 4 KW inverter few days last week and was consistently making 32 Kwh which surprised me as some days were quite hazy but I have learned that can either be nothing or significant.
32/4 = 8X inverter capacity which I thought was pretty good for a single orientation array at only 50% overclocking. As can be seen, Throw another couple of KW of panels east or west and 10X would be easy to achieve as I have before. I may have got more with a 5 KW inverter but then again, probably not a lot as it would only make up on the peak time the 4 KW was clipping and not any different for most of the morning and afternoon.
Going by the calculator, May, June and July are worst for me taking a steep dive in generation ability. Hard to imagine it's going to get cold so soon with another 30O day here today. The solar generation chart shows the nosedive though.
The one thing with solar is you can't have too much. If I didn't have a big tree out the front, I'd put up another 20 Kw on the east roof.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 10:13pm 05 Apr 2021
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That is an excellent calculator, and pretty much agrees with my own observations over the last several years.
The only thing I can add, is that it suggests panels directly facing the sun give highest output, which is undoubtedly true. However, in conditions of total grey evil cloud cover, directly up facing panels will always beat anything else by a small margin.
Its very helpful in deciding where to add any new extra panels if you have a choice of location. Edited 2021-04-06 08:14 by WarpspeedCheers, Tony.
Haxby Guru Joined: 07/07/2008 Location: AustraliaPosts: 418
Posted: 11:10pm 05 Apr 2021
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North facing is good if you don't have many panels and just want to maximise production, but if you are completely off grid, consider an East West orientation with oversize panels. Assuming a generous panel array, you want to maximise the hourly use of the sunlight while you have it, not just the production of kwh. So You won't cycle the batteries as much, and will recharge them as soon as day breaks. Getting that late afternoon sun is good for air con cooling and cooking before the sun sets.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 01:05am 06 Apr 2021
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I have an east west facing combination elevated to sixty degrees. It works really well in summer, adds at least an hour of useful solar at sunrise and sunset.
The sun actually rises and sets BEHIND my main north facing array in summer.
But throughout mid winter, the sun stays in the north and never reaches a high elevation, and the east west passive tracker is just not an efficient use of roof space in winter.
This was a bit of a surprise and a disappointment, but the "solar calculator" bears this out. I may pull it down and replace it with up facing panels for a much better result on really cloudy days during winter. Edited 2021-04-06 11:06 by WarpspeedCheers, Tony.
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577
Posted: 04:52am 06 Apr 2021
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Yes, I have found it extremely helpful and enlightening and it's save me a lot of time and trouble. Like anything, the parroted mantras on the net are often Purist and misleading in creating the impression of how things HAVE to be.
I was convinced I was going to have to tilt the panels on my 5 and 8o shed roof but punching the numbers into that calculator showed I'd be better off with them at roof angle over all and what I'd loose in winter wasn't really here or there anyway. That alone was a big wake up call.
I have punched a lot of numbers into that calc and printed things out I have put in a binder book for future reference. It's interesting how far things can be off the prescribed idea and loose very little over all and make gains in other ways.
Yes that's one thing that can't do. Maybe others can but everything else I have found was overly complicated and time consuming to use. Everyone always talks about ideal conditions but very few thank about when you need the power most, when the conditions are poor.
That's for sure! Even if one is committed to a non ideal spot, it can help with showing what sort of generation may be achieved.
Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577
Posted: 12:28pm 07 Apr 2021
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Finally got round to doing some work I wanted to do today. Hard when the Mrs is on Holidays telling you what SHE wants done all day.
Thought I'd go through the pile of waste oil burners and found something suitable that as I recall, never really worked that well. Just a gas bottle with a large air inlet and a fairly small outlet.
I want this to sit under a Gas water heater which the original burner acted on the base as well as the flue through the middle. As I want a broad rather than a narrow flame, I got the plasma cuter out and opened up the hole considerably. I thought before I go any further I'll give the thing a test fire to see if it will be any good or not.
I don't want much heat out of this so I am going with a 12V Bilge blower for the air supply. Long time since I used that but I recalled a few fire ups I did and the heat output was quite good. The thing with these is they don't have much air pressure so the large inlet on the burner I chose was perfect.
I found a plastic PVC spigot I bought for something els that didn't work out so I glued that to the bilge blower to take the flange mount to a more useful 50mm round output that with a little stretching, was able to put the round spigot in the square inlet hole as neat as could be. 1st win for the job.
I Normally won't go near petrol for anything fire related but I did have a few Litres of some ethanol racing fuel sitting around so I thought I'd be brave and do the burner pre heat with that. Put in a bit of diesel, put in a little of the race fuel, gave the fan a flick to push out any vapors and... took a bit of lighting with the little blow torch.
Soon as I hit the fan, it went out! Added some more, same thing, poured in a lot and got the show on the road. This stuff is pretty weak. Guess it's like Glorified metho. I think it's the same as E85, mostly booze with a little petrol thrown in.
With a damper over the fan inlet I got the thing going and put a bit of heat in it and was pleased with the flame output. The air inlet isn't the best, don't know why I did it that way, and it pushes the flame a bit to one side but under the heater than may be a good thing as it will swirl on the base and prevent a boundry layer of cold gas and create swirl up the inlet till it hits the diffuser anyway although I might try it without.
Anyway, Test showed the burner is a good match for the blower and the job I want. Should push out the heat I want -IF- the flue through the middle of the heater isn't too small. It should do 10 KW gas flow as that's what it was rated for but I Might want a bit more out of it.
The other thing is the air pressure. The air is expanded but the combustion so if it can't get out, it can't get in. The flue may draw some but I want slower rather than faster gas speed. I may be able to put a radiator on the top of the heater and pull some energy out of that depending on what the gas temp coming out is.
I sat down and wired up the burner controller tonight, very simple, Just a PWM for the fan speed and a timer for the Fuel pump. The pump is a magnetic pulse type so no problem switching it on and off as many times as aI like because the thing in operation Pulls on like a solenoid and then comes back with a spring in operation.
I'll start withe 1 sec on and 10 Off and go from there. From memory that gave a pretty reasonable output last time I tried it with a patio heater.
By controlling the air and the fuel I can ajust the output and burning quite a bit. These things will burn with a really wide air range and because they usually run on excess air run totally clean. The thing to be careful of is at low outputs, excess air also takes too much heat out the burner. These things work with retained heat and it's the oil Vapours that burn, not the liquid oil. The heat needs to be retained and the burner kept hot in order to make sure that vaporisation happens.
I like to run the burners red hot as that means the oil is not only vaporised but all carbonaceous deposits are burnt off and the things don't need cleaning as I see so many other designs do. They chisel out coal like clinker which is just incompletely burnt fuel.
Tomorrow I'll hook up the controller, see if I can find something to get an idea of what the oil delivery is at a certain time per minute and give the thing a burn to try and get some base line settings. They may well alter once the heater is sitting on top creating a restriction as it will but at least I'll have an idea which way I'm going.
I bought a new Circ Pump for this heating setup and of course fund the old one I hadn't seen in years today looking for something else. Also Found some heater cores that have also been MIA. Have some I have had for literally 30 years and some I picked up a while back. The old ones are think can heavy, probably out of old Holden's and the new ones out of Subaru's are Thin, Light and aluminium. The Subaru ones look like they will flow air much more easily than the Holden ones but the Holden ones look like they could transfer much more heat.
My Chinese Diesel heater arrived today. Very complete kit I must say. I'll get to setting that up at some point. I am hoping brother in law will be able to provide at least a couple of hundred litres of old diesel out of the battle ship he is restoring. Been sitting for some considerable time and obviously the fuel is an unknown other than very stale. I can easily dry it and filter it and that's all I'll need for a burner. I dropped him off a couple of 200L drums at his marina yesterday so hoping they will be filled and maybe another for good measure.
I also managed to find my 2KW 24V Inverter today. I got out my old solar controller setup and put that on a Big Battery BIL also gave me but I'll need another to go with it. Not sure what I'll do with it yet, just really wanted to have a play with this stuff as it was my first foray into solar and I liked playing around.
Might Drop into the scrappy tomorrow and see if he has any decent water heaters, both electric and Gas. I'd be happy to get a larger gas heater than the little one I have so I know I could do more heat transfer with it. A 400L electric would be good for heat storage.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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