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Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462
Posted: 08:06pm 30 May 2012
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[quote] … The introduced warm air is fresh air from outside, positivly replacing old cold air …
[/quote]
Hi,
Quite impossible here with just a few neighbours around using wood heaters.
Air is so foul, that all the houae air replacement has to be done early in the morning, or strategically during the day (depending on wind direction) and not at all at night.
Is there a way to use system like yours with (unfortunately) recycling air throughout the house?
George
home heater Newbie Joined: 03/03/2010 Location: AustraliaPosts: 9
Posted: 11:41pm 05 Jun 2012
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Hi Georgen, yes, you could recycle your air with a bit more ducting. Mine draws fresh air from under the iron corrugations. These are easily blocked with plumbers foam, then cut a suction vent inside the ceiling at the bottom of the roof. Take this vent to floor level so you are taking the coldest air to reheat, and introduce your heated air at the ceiling. Try to get the longest route for the air to heat under the roof. A bit of sisalation to direct your air flow. All vents need an air door to prevent thermosyphoning when not heating.
I painted the roof with blackboard paint thinned a bit, you are really only after a colour on the iron, not a thick coat of paint. Dark coloured colourbond would be good, doesn't have to be black. Glass shower screens work fine to cover the roof, just keep adding them as they turn up at the tip shop. Another one is those glass topped outdoor tables, they end up rusting their legs away, then they go to the tip shop. I screwed the roof screws in a bit so the glass misses them, shower screens and sliding glass doors have an aliminium surround so they miss the screws.
Thanks Glen, yes I have two refurbished hot water panels going and a third to do. The end is rusted out but a squirt of plumbers foam and cover with fibreglass and resin will fix that, and I have a large sliding glass door (tip shop again) to cover it. Often see panels on eBay cheap but interstate collection is the problem. Cant help with the smiley Glen, but I had a smile myself when my post went in, and with smiley!!! Will see if I can edit it out when I post this.
Allan ...........javascript:AddSmileyIcon('')do it yourself
Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462
Posted: 12:54am 06 Jun 2012
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Hi Allan,
Would you be able to show some pictures of specific parts of your system?
Our roof is covered with black concrete tiles.
They don't get too hot in winter, but even if air is 20 degrees or so it still eases work of the electric heater or AC unit.
I always agonise, why I cannot store summer heat for winter and winter freezing temperature for those scorching days in summer easily and cheaply.
George
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 11:42am 06 Jun 2012
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Update
Well, as luck would have it, my retirement plans have changed . . . for the better!
I'm in the process of purchasing a 5-acre ranch in Texas. When I move there, my current intention is to lay a serpentine stretch of half-inch soft copper on top of a layer of black asphault road material and then cover it with the same stuff, roll it, oil it and use it for a dual purpose. It will serve as both a walking surface as well as a heat collecctor in all seasons.
Texas' ground temperature in the summer soars above 115* F on pretty much a daily basis. Using pre-heated water from a solar array burried in asphault in addition to my infamous "Death Ray" concentrator, I'm going to make steam! I also intend using windmills to pump air and water in attempt to utilize the constant low-level prarie winds that blow on an almost-daily basis.
In the winter, when there's snow on the ground, I'll either back-flush it with stored warm water to keep the walking surface free of snow, ice and moisture or maybe just use stored compressed air from my air-pump windmills to blow the water out awaiting warmer weather.
By keeping the heat colletor at ground level, one or several tanks can be set upright on the ground and the entire system will "thermo-siphon" eliminating the need for a circulation pump. What could be easier?
As a side note here: I also intend scooping out a ginormous fish pond on the property and use that excavated dirt to buttress the sides of ground-level concrete and block structures to be used as storage and perhaps even living quarters, which will be tornado proof. Flooding may be an issue, but I'll cross that bridge when I get to it.
This project should be in full swing by the end of August, this year. I'll keep everyone in the loop, likely by new posts in both Solar, Windmills and maybe even in Other Stuff and not bring it back here, not wishing to hijack this thread.
. . . . . MacNothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462
Posted: 03:32pm 06 Jun 2012
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[quote]
. . for the better!
[/quote]
Congratulations !!!
Looks that you’ve got too cramped in your caravan, or offer was too good to refuse.
George
Jarbar Senior Member Joined: 03/02/2008 Location: AustraliaPosts: 224
Posted: 05:48pm 06 Jun 2012
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Really need to find the reason for that "javascript:AddSmileyIcon('')" text that pops up occasionally, got me beat
Could be the transit of Venus.
Anthony."Creativity is detirmined by the way you hold your tounge".My Father
"Your generation will have to correct the problems made by mine".My Grandfather.
powerednut Senior Member Joined: 09/12/2009 Location: AustraliaPosts: 221
Posted: 12:58pm 07 Jun 2012
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Hmm.. i thought that while water does hold more heat than oil, oil heats up roughly twice as fast... and sheds it twice as fast as well, making it pretty damn good if you do want to go with a 2 heat exchanger system.
and doesn't also ammonia hold heat better than water?
One question I have for you guys is how do you stop the thermo siphon effect happening in reverse when its night and cold out?
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 02:11pm 08 Jun 2012
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powerednut,
install a inline check valve.
They used amonia in the fefrigerators many years ago, a good phase change.
Mac46I'm just a farmer
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 03:27pm 08 Jun 2012
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Hi Home heater,
what sort of depth is the heated air space under the roof sheeting? is there an advantage to having a larger volume of air?
It is a brilliant solution that you have built, I am wondering if it can be adapted to other situations like sheds. There are a few houses around here that are double skinned with a colourbond tile over a corrugated iron roof with a thin batten separating the two I am guessing it would not take much to adapt this to heat the house.
Yahoo
I'm confused, no wait... maybe I'm not...
home heater Newbie Joined: 03/03/2010 Location: AustraliaPosts: 9
Posted: 02:38pm 12 Jun 2012
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Georgen,
Hi Allan, Would you be able to show some pictures of specific parts of your system? ====== email me if you like jfscott(at)optusnet.com.au
Our roof is covered with black concrete tiles. ====== Sorry to tell you that tiles leak too much air and take too long to heat. On saying that a north roof system would still work, but at lower efficiency, they will take longer to heat than iron, your tiles are the right colour. They have to be covered with laserlight or glass. I was in my mates tiled roof space a while back and it was very warm, red tiles, no covering. Whatever you put on your roof has to be properly fixed so as not to blow into your neighbours back yard in a storm.
I always agonise, why I cannot store summer heat for winter and winter freezing temperature for those scorching days in summer easily and cheaply. ======= There is no (affordable) insulation that will keep heat for that period of time. We (Portland, Vic) get enough winter sun to heat our house. More often than not there are a couple of hours sun. A hot water cylinder will go to luke warm in two days without heating. You would need a swimming pool in a (very large) thermos to save summer sun.
kent_323is,
Go solar, to heat with wind is a very big undertaking. Passive solar will go for many years unattended, have a read on the www for wind generator problems, even commercial generators have troubles. (add whisper 500 to your search) Designing your own large machine and getting it reliable is something some of us have tried, is a long process. Solar flat plate collectors are ultra reliable, available 2nd hand, collect lots of heat, have no moving parts, the exception being a little circulation pump.
Powerednut,
Hmm.. I thought that while water does hold more heat than oil, oil heats up roughly twice as fast... and sheds it twice as fast as well, ==== Thats because oil takes less than half the heat to make it the same temperature as water. You will be pumping more than twice the amount of oil to get the same amount of heat transfer. You can not beat water for domestic heat transfer.
and doesn't also ammonia hold heat better than water? ====== From what I have just read, yes, but you have to buy it, you have to have a vacuum pump and fridgies gauges to use it, it needs to be contained in a sealed system in steel pipes (it corrodes copper). You will shift all the heat you need to with easy to use, free, non toxic, non poluting and plentiful water.
One question I have for you guys is how do you stop the thermo siphon effect happening in reverse when its night and cold out? ======= Vent(s) must be fitted with a motorised air door. I made mine with electric car door window winders, which you will get for nothing. They need two micro switches fitted for end travel stops. Get the rear door mecanism, they havn't done much work.
Yahoo2
Hi Home heater, what sort of depth is the heated air space under the roof sheeting? is there an advantage to having a larger volume of air? ======= Mine is two inches(shows my age, 50mm then) but it doesn't matter. A larger volume of air will take a little longer to heat, but with 30 sq mt of glass collecting 15kw you wont notice the difference.
It is a brilliant solution that you have built, I am wondering if it can be adapted to other situations like sheds. ======= Any north facing corrugated iron roof with good sun can be used. Heat can be pumped from the shed into the house.
There are a few houses around here that are double skinned with a colourbond tile over a corrugated iron roof with a thin batten separating the two I am guessing it would not take much to adapt this to heat the house. ======== Now thats unusual, my guess is the tiles cover a rusting iron roof maybe. Yes, this will work fine. You will get a small leakage of air under the tiles but I dont see a real problem, colorbond tiles fit together pretty well. As long as the air flow starts at the bottom of the roof and extracted at the top it will work well. You will be loosing heat from under the old corrugated iron but tack a roll of sisalation under that to decrease heat loss if necessary. Hot air is generated between the colorbond tiles and the corrugated iron.
My thoughts on Evacuated Tubes:
Efficiency is of no importance, the energy is free.
They are capable of boiling water, creating steam and the need to vent it. They are now selling heat exchanges to get rid of excess heat in evacuated tube systems. A tube system should be installed for a winter collection angle which will reduce summer heat collection. Flat plate collectors do not have boiling problems.
No doubt tubes come in different qualities and a bad lot will be more trouble than they are worth.
I looked at a new install a while back and noticed more than one tube hot, ie lost its vacuum. And thats a brand new system. Those tubes were faulty before they were installed. (I dont know where they were made)
They are fragile. They are a high tech device, a flat plate collector will last decades without attention.
Have a read on the www, there are some installers recomending flat plate collectors over evacuated tubes because of their problems.
The reliability, durability and lack of boiling problems of flat plate collectors makes them a better alternative. Remember, efficiency is of no concern as the energy is free.
Allan .................
12.30am, 23degC inside, 3degC outside, 12.06.2012
Edited by home heater 2012-06-14do it yourself
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 04:09pm 12 Jun 2012
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Many years ago when I worked as a Technical officer at "The Victorian Solar Energy Council" we funded and supported several solar home heating projects of various types.
All were expensive failures when looked at from the economic perspective and comfort level provided.
The idea that a solar collector and a heat storage system of some kind will keep you toasty warm all through winter is just not going to happen.
It only works when you have very high temperature variations from day to night, such as out in the desert. And most of the gain is achieved purely from thermal mass and good insulation, rather than active heating or cooling from a large stored heat source/sink.
Your best bet is to design your home with very high thermal mass, and high values of insulation, and design for passive heating and cooling using the greenhouse effect for heating, and convected air with evaporative cooling in summer.
Plant deciduous trees to provide summer shade and for direct solar gains in winter. Wide eaves keep the sun right off the walls in summer, but allow the low angle winter sun to stream in through large glass areas. Ventilate the roof space to prevent heat buildup in summer, ceiling insulation will keep you warm in winter and cool in summer.
Things that do not work are pumped hydronic systems and rock pile heat storages. It is simply not possible to store enough heat that will last long enough to be of much practical use. Active systems with very high heat storage are expensive to build and in my experience are always a big disappointment.
Several tens of thousands of dollars will buy a LOT of combustible fuel and kilowatt hours for air conditioning !!!!
If your cleverly designed energy efficient home requires very little additional heating or cooling except for some extremes of maybe a few days or a few weeks each year, the cost of running traditional heating and cooling will be minimal, and the comfort level much better.
Solar and wind power are ideal for electrical power and heating water.
For keeping you warm all through a freezing winter, without any supplementary heating, forget it.........Edited by Warpspeed 2012-06-14Cheers, Tony.
Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462
Posted: 02:13pm 13 Jun 2012
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Reminds me of article about sort of underground house in USA, in the area with snow in winter, that had R60.
Where 4 people and the dog produced enough body heat that no additional heating was necessary.
George
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 02:39pm 13 Jun 2012
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I can well believe it George.
In my youth I spent a couple of years in the Antarctic (on Australian bases)
We read about how the Eskimos lived quite (relatively) comfortable in an igloo, and how people had survived for long periods completely buried in snow from avalanches, and how Polar Bears hibernate buried under snow.
So we cut up some snow blocks with a chainsaw and built ourselves a little snow house.
With just a candle and body heat, the walls glazed to clear ice, which kept the drafts out. Still air and soft snow are both pretty good insulators and if suitably dressed, it did not feel all that cold in our little home.
Certainly warmer than out in the sub zero howling wind we could still hear outside.
Only yards away, the other guys in tee shirts drinking beer in central heated comfort and watching a movie thought we were both completely mad.
But it was definitely fun, and an experience to remember.Cheers, Tony.
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 04:00pm 13 Jun 2012
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[Quote=Powerednut]
One question I have for you guys is how do you stop the thermo siphon effect happening in reverse when its night and cold out?
There are three solutions to this question:
First, like Mac 46 said, you can install a check valve. If you do this, be sure to use what is called a "swing check" and mount it in the horizontal position and NOT vertically. It uses gravity and flow to prevent reverse flow. A spring check will just stay closed in a closed system.
Second way is to install what is called a "solar loop". This consists of running the inlet (cold) pipe in the shape of a loop. Heated liquid does not like to flow against gravity. Be sure the loop is longer (taller) than it is wide or it will find a way to cheat.
Third and best way is to construct the solar-heating application such that the collector is installed UNDER the receiver (tank). At night or when the air temperature drops, heat rises. It will NOT flow against gravity.
Hope that helps you out.
. . . . . Mac
Edited by MacGyver 2012-06-15Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462
Posted: 11:46pm 15 Jun 2012
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Noticed on E-Bay thermostat:
240V, 2000W
temp. range (-)9 to (+) 38 Deg C
The Thermostat has a Waterproof Probe with 2.3 Meters cable
Picture copy from E-Bay
Quite inexpensive alternative to turn on and off fan pushing warm air
and 2000W capacity could serve quite a few fans if needed.Edited by Georgen 2012-06-17George
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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')
