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bobrok
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# Posted: 16 Nov 2010 09:30am
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I did a forum search and didn't find anything on the topic so I would like to create one. I am looking for a mechanically operated ceiling fan for my camp. It can be spring wound, weight or torsion driven, or anything that would allow a non-electric means of moving air. Primarily I want to be able to circulate heat down in the cold weather so that there is not such a difference in temperature between the ceiling and floor.
Has anyone ever seen one of these?
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MtnDon
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# Posted: 16 Nov 2010 10:47am
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I've never seen anything like that. I think the problem would be storing enough energy to provide the necessary speed on movement. A clock with it's slow moving hands is one thing, but a fan is quite different.
Is this just a "it would be cool" thing or a need because of no electricity? If the later, there are fans that run off 12 and 24 volts DC, ideal for off grid applications. We have one made by RCH. If anyone is interested just Google RCH ceiling fan.
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fooboo
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# Posted: 16 Nov 2010 11:45am
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Have you ever been to a Dave and Buster's? They have ceiling fans that are powered by a belt driven system and all the fans are interconnected. You might get some inspiration from that. Perhaps you could integrate a homemade wind turbine with a belt driven ceiling fan - the outside breeze would power your inside fan.
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islandguy
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# Posted: 16 Nov 2010 08:36pm
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Simple attic fans use wind to turn them and vent an attic space, but wouldnt circulate heat inside very well.
There was some discussion on this site before about mechanical powered fans. A weight driven mechanism could be used by incorporating an "escape" mechanism, such as a music box or clock mechanism, and there are, somewhere, plans on the internet for a weight driven movement made out of wood. A better alternative might be a fan driven by heat from the wood stove, assuming you have one. There are some commercially available that sit right on the stove and blow the heat around the room and use only stove heat for power. Good luck
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bobrok
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# Posted: 17 Nov 2010 05:59pm
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Thanks, MtnDon, fooboo & islandguy for the replies.
You have all made valid points and asked good questions, but before I get to deep into this (and in the interest of full disclosure) I want you to know that I have been guiding a thread on another forum on this topic for almost 2 years now. I am frustrated because although there is an enormous amount of interest and response, no one form that forum has come up with a working solution yet, although very close. I do have one contact with whom I have already spoken who claims to have made these fans and still makes them to order and I am going to pursue my conversation with him, but just haven't had the time to do so.
I don't want to bore anyone with details unless there is interest here, but I just had to pose the question since I have been absent from this forum for quite a while and I really want one of these.
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MtnDon
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# Posted: 17 Nov 2010 06:41pm
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bobrok, that sounds interesting. I'd love to see that thread if you could point us at it.
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islandguy
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# Posted: 17 Nov 2010 08:18pm
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An pendulum would work well, and be simple to construct. One large enough to run a fan for say,half an hour, would be fairly large though, and take up quite a bit of space. Ceiling fans use very little energy, so a mechanical powered one doesnt seem like it should present much of a problem. A flywheel would work as well, but would be difficult to get it to work for more than a few minutes at a time. Even a tank of water gravity feeding a small waterwheel or turbine would turn a fan and the time would only be limited to the size of the tank feeding the fan. Just some ideas, but I still think a weight driven movement is still the most likely way to make this work, and still be practicle.
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bobrok
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# Posted: 18 Nov 2010 11:16pm
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MtnDon, here it is for your reading pleasure: URL
As you will see this conversation has been going on for some time. Although I have stopped instigating and the posts have fallen off lately I still monitor the thread and respond when I feel necessary.
Very recently I received no fewer than 3 private e-mails in one week from people who wanted to know if I had found or built a fan. I know there is a lot of interest. When you get to the part with the Georgia Tech student that was about as close as we got to actually seeing one of these fans 'in the flesh'. "Gary" and I communicated privately quite a bit during and after his course and he sent me photos. Although they never quite achieved their course objective of building a useable working fan, (he explained the obstacles they ran into from a mechanical & time perspective) they did build a working prototype.
I hope you enjoy reading this and I look forward to your comments and those of others here as well.
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MtnDon
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# Posted: 19 Nov 2010 04:34pm - Edited by: MtnDon
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Interesting. The Dutch art/machine is cool, but to me, is more art than a practical, efficient machine.
It would be nice if the accompanying info stated the rotation speed of the fan or how long the unit would run on one weight fall. Judging by the length of the blades and their slender design I would guess it turns relatively slowly compared to a typical electric ceiling fan. Interesting gear train. See if you follow my logic on this and please have a hard look to see if it makes sense or if I've made some grossly incorrect assumption or calculation.
It's hard to know the diameter of the gears. Maybe 12 inches for the large ones? One of the small photos would suggest maybe 12 inch diameter if the ceiling height was 8 feet. But that's a guess. If the ceiling is taller the gears would be larger. ??? Using the same picture the distance the weight pack could fall would be 6 feet or so maximum.
The way the weights are hung, the movable pulley multiplies the cable travel at the first large gear, the one with the cable drum, by a factor of two. So if the weights fall a distance of 6 feet, 12 feet of cable will be unwound from the drum.
If we assume the large gear to be 12 inches in diameter that would place the cable drum at a 6 inch diameter, estmating from the photos. A 6 inch drum has a circumference of 18.8 inches. Twelve feet of cable divided by 18.8 inches equals 7.6. That would be 7.6 revolutions of the large gear with the drum.
I enlarged the image and counted gear teeth. The large gear has 80 and the small gears 16, a ratio of 1:5 (large gear turns once driving the small gear through 5 revolutions). There are three sets of large/small interfaces for an overall ratio of 1:125. It's impossible to say for sure from the photos what the ratio from the set of bevel gears is but there is a good chance that from there up to the fan everything is 1:1.
So for every revolution of the large, cable driven gear the fan would turn 125 revolutions, by my estimation.
So it follows that the 7.6 revolutions of the cable drum gear will produce 950 revolutions of the fan. What sort of time interval of course depends on the speed of rotation. Sixty RPM's produces almost 16 minutes, 120 RPM nearly 8 minutes.
The information from the Dutch site states the weight pack is 120 kilograms, 264 pounds. Yikes! That is a lot of weight. There is a crank handle on the cable drum gear. So it appears that would be used to raise the weight back to its upper position. That amount of weight suggests to me there is a lot of friction in the machine. From the pictures there does not appear to be a speed regulation mechanism. There may be but it is not readily apparent. Perhaps friction is relied upon to moderate the speed of the fan. ???
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MtnDon
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# Posted: 19 Nov 2010 04:38pm
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Another thought from the other thread... Using torsional springs like from a garage overhead door. Winding those springs up takes a great deal of effort as the tension increases. Any mechanism using this as a energy source would have to incorporate some failsafe methods to prevent serious injury. Bones can be broken, or worse, if the tension stored in an overhead door spring is suddenly released.
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MtnDon
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# Posted: 19 Nov 2010 04:41pm
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Dutch art/machine links
one
two
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jjmofo
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# Posted: 20 Nov 2010 11:12am
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These little guys at Lehman's are heat powered.
http://www.lehmans.com/store/Stoves___Hearth_Accessories___Heat_Powered_Fans___Wood_S tove___88510?Args=
Could you take advantage of its mechanicals?
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PhylB
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# Posted: 20 Nov 2010 09:39pm
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Sounds like you need a heat pump, not a ceiling fan. Ceiling fans can't get the heat to the floor. They can mix the hot and the warm in the top half of the space OK, but not much of the coldest air is affected. If you had electricity, I'd say just mount any 6" fan in your rafters, pointing down toward the floor.
But without it, you can build a heat pump from a PC case fan that runs on 12v DC power and use any kind of ducting material as the conduit for the hot air from the ceiling to the floor. I've made both kinds, 110V Ac and 12V DC. Not hard to so and very effective.
I had seen a heat pump on the site below a few years back amd thought it was rather neat that he was selling a complete unit for comparably little. Now, he also sells just the 'works' and provides instructions to build your own. Check it out.
http://www.heatstick.com/_Heat%20Stk03.htm
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bobrok
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# Posted: 22 Nov 2010 10:25pm - Edited by: bobrok
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MtnDon,
I am impressed at the effort you have put into that gear work! Are you an engineer?
PhylB,
That type of device looks like a very simple way to move heat downward. I just happen to have two old computer towers sitting on my basement floor and might cobble something together to try out over the winter.
Thanks.
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MtnDon
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# Posted: 22 Nov 2010 11:47pm
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Quoting: bobrok Are you an engineer
Only 2 1/2 years towards a 4 year degree; then I got sidetracked by a hobby turned career.
The heatstick looks like a simple enough and effective method. It could even be used to move heat horizontally and then down as well.
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PhylB
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# Posted: 23 Nov 2010 09:59pm
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Glad you like the concept. It really does a pretty nice job. First time we made one was back in the 80's for a friend who lived in an apt in NYC. One of the 1930's buildings, 14' ceilings, 6-7' windows. You could probably make popcorn off the air at ceiling level and still feel like you'd be skating on ice if you spilled water on the floor. Made it liveable. Oh, and in the summer, we hung it the other way around, to pull the ac air up.
If you use flexible ducting - like silver dryer vent - you can bend it around obstacles. For that type of configuration, I'd recommend 2 fans, one midway and the second close to the exhaust end.
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bobrok
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# Posted: 24 Nov 2010 07:18pm
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PhylB, on your 12v DC heat pump version I assume you used a PC cooling fan since that is what you mentioned, but tell me if it was something different. In any event what I'd like to know is what size rechargeable battery I'd need to use to power a PC fan and how much operating time I could typically expect from it.
The whole concept of my post here was to make a non-electrically powered device, but this idea seems so simple in concept (portable and lighweight) that it might work for me if I didn't have to lug too many more batteries back and forth with me. I would want to operate this separately from my PV system.
Thanks for your input.
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PhylB
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# Posted: 24 Nov 2010 09:56pm
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bobrok,
For the DC pump, we used a PC fan wired to a lighter plug, for use in a 12V battery bank system that was connected to a 45W solar panel and a 10W vawt. I'll have to do some research on alternate power, like the rechargeable batteries you mention. I know that there are lower voltage fans, 3V and maybe 5V, but I'm unfamiliar with those configurations or the amount of power they draw. Also, I have no idea what they cost. A new PC fan averages around $5.
The PC fans we used draw less than a watt - about .70-.80w, so running the pump 24hr would draw about 18 - 20watts a day. The drain on your PV system would be quite low. You could probably offset it with a simple trickle charger, like the ones you can buy for a car battery on eBay at around $20, added to your current system.
I'll do a bit of research and consult my nephews - the electricians - for a better idea of the options.
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bobrok
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# Posted: 26 Nov 2010 07:26pm
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Thanks for the offer PhylB. I do appreciate it. I'm up at my camp right now and trying to do all sorts of temperature measurements off the ceiling, floor & midpoint so I can get some hard data on temp differentials. It's consistently about a 15 - 20 degrees (F) difference between the high & low points even as the place heats up. My ceilings are only 8 feet so I don't really have a lot of clearance for a ceiling fan. I may rig one up just to see how effective it is but your comment about a ceiling fan not being very effective on moving the coldest air off the floor worries me about this whole concept now. Looking forward to seeing what your 'exert associates' might have to say about powering a small duct fan. I may also reassess the power drain on my pv system. The problem I see is that if the batteries cannot power the fan long enough I would have to resort to generator (AC) power and have to swap out the DC fan for an AC fan.
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fasenuff
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# Posted: 27 Nov 2010 10:58am
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Last summer I bought at Walmarts a 12v fan that will work on either 12v or 8D batteries. It will operate for about 24 hrs on the D batteries or use very minute amount of my 12v battery. It worked so well I bought a second one. Since firing up the wood stove I have mounted one ib the rafters of the new cabin and set it on low(they are 2 speed) and faced it downward with a switch in line so I can turn it on and off with out climbing in the rafters. It has helped a lot with circulation of the heat. I plan to mount one in front of the gable vent to move out heat from the attic this summer. Cost was low and it so far has been a dependable fan.
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bobrok
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# Posted: 27 Nov 2010 03:43pm - Edited by: bobrok
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Thanks fasenuff. I'm gonna check that one out.
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just trying to help
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# Posted: 30 Nov 2010 01:47am
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I JUST bought one of those myself last week to use as an exhaust fan at the rear window of my truck camper to control condensation and they are ridiculously powerful for how small they are! :)
I bought mine at walmart for under $20.00 (it was either $14.99 or 19.99, can't remember) but I found a link for the same brand at amazon here: http://www.amazon.com/O2-Cool-Model-1054-Indoor-Outdoor/dp/B000I4L15Q For some reason walmart.com doesn't have this one listed, but they have it stocked at my local store...
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bobrok
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# Posted: 30 Nov 2010 08:43am
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Thanks jtth. I checked it out and with a little clicking around I found that they also make a rechargeable version of that fan. Now this looks promising for me since it is self powered with its charge pack.URL
What I'd also like to do is make one of those tube fans like PhylB described above and power it with a rechargeable fan. I'm thinking about how I might find an old rechargeable devicelike an inflator pump and modify it to use in the tube fan.
Ahhh...winter project...and then an excuse to go back up this winter to try it out...love this idea.
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hattie
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# Posted: 30 Nov 2010 12:00pm
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From Hattie's Hubby (cuz Hattie doesn't know what the heck you are talking about *S*) - Since you have a source of heat (ie woodstove), you should be able to use a "Stirling engine". They were invented in 1816 and are an EXTERNAL combustion engine. It's a closed cycle engine operating on the pressure created by air moving back and forth between heat exchangers. An external heat source (ie your stove) warms one exchanger. Lee Valley Tools in their Christmas 2010 catalogue sell one in kit form for $189 (item # 45K39.80 on page 13). A bigger version is being used to power Sweden's new super quiet submarine.
You would then gear down the output of the engine to run a fan. I am not saying the one that Lee Valley sell is big enough to do the job (although it might be), I am just giving you an idea that you might want to pursue.
From Hattie - boys and their toys, geesh!
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bobrok
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# Posted: 30 Nov 2010 12:49pm
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I've read about them and I believe they were discussed on my other forum way back towards the beginning of that thread somewhere.
The point I want to emphasize is that while I do have a source of heat, it is a propane heater unit with a thermostat. It turns itself on and off and doesn't constantly pump out heat. I don't think any radiant heat powered device will work when the heater is not running. And the purpose of moving heat down from the ceiling is to mix the air quickly during the camp warm up process and thus cause the heater to cycle even less often.
I do appreciate your comment. Thanks HH.
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wec502
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# Posted: 7 Feb 2011 12:01am
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What about a chain siphon? Power and speed regulated with the head (Fall) of the chain.
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larryh
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# Posted: 7 Feb 2011 09:31am - Edited by: larryh
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I have one of those little battery powered fans they are not going to answer the issue of moving heat off the ceiling in my opinion, but heck I could be wrong. My best guess is as has been said, a batter powered 12v fan using solar panels to keep it charged and running. I think that is going to be the closest thing to successful your going to get. I have never really used one of those stove top fans but they operate on the similar principle to the old kerosene run fans. Trouble was they put out more heat than the movement of air was worth. But maybe if you could tilt the fan to point towards the ceiling it might move a bit of air down, but I would be surprised you would know the difference.
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bobrok
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# Posted: 7 Feb 2011 07:17pm
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Quoting: PhylB I'll do a bit of research and consult my nephews - the electricians - for a better idea of the options.
PhylB: did you ever get any more info from your nephews?
I've since acquired two 12v. dc computer fans in good working order and am waiting for the time to rig up one of these gizmos. For starters, and to stay on the cheap side, I'm going to get my hands on a cardboard carpet roll tube from a store and just throw it together to see if it works in real time. If it does I'll tweak it to see what makes it work better. I like this fan concept so much that I'm abandoning the ceiling fan for now in pursuit of this.
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soundandfurycabin
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# Posted: 8 Feb 2011 04:16pm
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It's consistently about a 15 - 20 degrees (F) difference between the high & low points
Do you have a vented attic above your 8 ft ceiling? You could consider a different approach. With such a large temp difference between floor and ceiling, what's most likely happening is the heated air is rising to the ceiling, passing through gaps into the attic, and drawing in replacement cold air at floor level. If you can seal up the attic floor, you break that cycle and the temp difference will be much smaller. Get up there and use expanding urethane foam to seal up all the gaps you can. Use aluminum flashing and and high-temp caulk around chimneys. Add weatherstripping to the attic hatch. This might help...
http://www.jlconline.com/cgi-bin/jlconline.storefront/4d51b0ef05fb6eaf27170a32100a066 e/UserTemplate/69?s=4cdf59d30ba0403b27170a32100a0639&c=b4dc1d74a535ffbdc4d6441b1e1f22 3c&p=1
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bobrok
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# Posted: 8 Feb 2011 05:39pm
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Thanks for linking that article soundandfurycabin.
I do have a vented attic crawl space and I upgraded to R-50 fiberglass. I immediately noticed that this made the place much warmer and held the heat longer. Haven't hit the seams with caulk or foam but that is certainly something to look into. I don't notice any drafts at floor level so I don't think I am drawing in outside air to any great extent through the bottom areas. I think its just the striated heating levels that become so obvious in a small space.
Of course I do keep two windows cracked open for ventilation since I have a non-vented heater. I know this is counter-productive to keeping cold off the floor, but you've likely read on another thread here about the necessity of venting for heaters.
As I said above I'm going to cobble together a tube-type fan or fans and see how that works.
Best case will be to find a balance that works and live with it.
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