heated by the winds

[Mentally Moribund]

I have been remodeling my house and triing to get it more air tight and insulated.  When I moved in there was no insulation and the previous owner had $600+ a month gas bills for heating!  I have gotten it down to about $300 which is still horrable for a 1200 sqft house.  I have built a wind gen for the sole purpose of aiding in the heating of my house.  I wanted to build a water heater and run hosing through the floor, however, There is not enough crawl space to do this (although I plan to do this in my garage and build a second wind gen to heat my garage, which ironically is well insulated).  Anyway, Here is my nw thought - a heated rug, much simular to a electric blanket.  

I found a company (http://www.speedheat.com/us/index.htm)that makes this product already but its too pricey.  Any sugestions?

[walsdos]

Am in a similar situation and have used water rad which I hope to utilise. However , family and friends with in floor heating swear by them.More comfort,Even heat distribution, Smaller temperature gradient, lower energy consumption.

  If at all possible lay a cement upper floor incorporating the heater pipes.Fluid heating gives the flexibility to use any heat source.

Good luck.

[iFred]

I can find no real differance between this and a heating blanket. would try a heating blanket for a test just to see what will happen.

[p0lizei]

My thought is that a heating blanket would be more efficient than using the elctricity from your turbine to heat water to heat your house.  That is an excellent idea, plus you don't have to muck around with piping and water pumps (you'd probably use glycol, that's what I've always seen in use for this purpose).  

My goodness, this goes down in my Book of Whoa Ideas.  Good job mate :0D

[Chagrin]

Heating a tank of water would store the energy more economically than a bunch of batteries.  

[rotornuts]

This is the driving force behind my renewed interest in wind power. I want to run an electric hot water tank on wind and run the hot water through a heat exchanger and move it around via forced air. The heat exchange is basicaly a section of duct with copper tubing coiled in it. Hot water goes through the coil, air goes through the duct and presto hot air.

here's one I built as a test.

This is one section of 6" duct with 50' of 1/4" copper tube in it. couple with a 250 cfm duct fan it works although off the top I can tell you that 1/4" copper is too small. I will try 3/8" next.

If you are allready using forced air this is a cheap way to go and water has a distinct advantage: in a well insulated storage resevoir it will stay hot long after the wind stops blowing, absolutely perfect for wind power.

[iFred]

OK, this is absolutely HOT! Now wait one darn minute. I have a space heater about 50,000 btu. IF I where to build one of these to preheat water for my hot water tank, would this not restrict the exhaust flow thereby increasing it to make up for the difference and using more fuel? Or would it not? In which case this makes sense? help!, loosing mind...

[tecker]

  I follow this looks like a good addition to any gas exhaust pipe increase the size and add the copper coils .

[tecker]

  Put the coils close to the pipe and use copper stand offs to keep the electrolysis down.

[rotornuts]

This concept can work in many ways. You could as you say possibly use it to recapture heat from a gas heaters exaust provided you don't restrict the flow of exuast causing it to back up into your house(carefull with that). You can heat water with wind, run the hot water through the copper, forced air through the duct and as I said presto hot air! I've seen this idea used to recapture heat from drain pipes and preheat water headed for the hot water tank. I suggest googling around for anyone interested - type in, heat exchanger copper coil, to get some ideas. The reason for not placing the coils closer to the wall of the pipe was to maximize air flow around the pipes, that's also the reason for the cap in the center at the exaust end of the duct, to force the air to flow around the copper pipe. At first I had no cap at the end and the air flowed mostly through the center and little heat was tranfered to the air.

Another thought I've been having is to make a coil or several from one piece of copper to place in the square exaust or outlet section on my funace ahead of where the air is ducted around the house and use the existing system completely.

Surface area and the speed at which you pass the fluid to be heated(air, water, hot exuast gas for heating the water etc.) will help determine the tranfer efficiency.

This is one to play with. It's an old idea with many possibilities.

[troy]

Dear Fred,

The original poster is suggesting to heat the water from wind manufactured electricity, then pipe that hot water through his nifty duct with copper coil for heated air, the now heated air to be circulated in his house.  That should work great, providing he has a big enough mill to make a real difference.

Your idea to recapture heat from the exhaust stream of a fossil fueled heating appliance would work, BUT...

1.  It may cool the exhaust enough to cause corrosive condensation to form, then you'd need a condensate pump and a good plan to get the flue to drain properly.  Stainless steel would also not be a bad idea.  Stealing heat from the exhaust until condensation occurs is exactly the difference between a conventional furnace and a high efficiency furnace.  All the high efficiency furnaces have a provision for condensate pumps.
   
2.  If you are going to use water to reclaim the heat in the flue, you need to have redundant temp and pressure safeties in place in case you heat the water to boiling and cause a nice little bomb event.  One gallon of water superheated into steam and then released catastrophically has approximately the same energy release as a stick of dynamite.
   
3.  The new heat reclaiming flue should have the same available cross sectional area as the unrestricted flue, plus a bit more to compensate for the turbulence caused by the coil.  If you cool the combustion products too far, you lose your draft, which is really a thermosyphoning gas.  Really efficient heaters generally use forced draft (aka fan) to compensate for that reduced or non existant thermosyphon effect.
   
4. Your insurance company would happily deny any claim for damage to your house caused by a non-approved heating appliance. Unsympathetic inflexible jerks that they are.
   
   

Good luck, have fun and play safe,

troy

[walsdos]

Hello rotornuts,I have a water heat ex, 19"X19"X4 rows of tubes, in thew plenum of the forced air oil furnace.... v similar to auto rad. It allegedly transfers 100000 Btu's with water at 180deg F but in practice much less than that when compared with the 100000 Btu oil furnace.

    Experience suggests that water/ air heat exchangers are more efficient when the air is "sucked" through rather than "pushed" through.So you would likely be better off putting your coils in the inlet side of the blower.

[richhagen]

I suspect you could also modify a central air units a-coil for use as a heat exchanger with hot water/ethelyne glycol in a forced air heating system.  Rich Hagen

[richhagen]

Hi, Intuitively I would have placed the coils down stream from the blower.  Since the flowrate across the coils is determined by the pressure drop it seems to me that it shouldn't make a big difference which side of the blower the coils are on.  Since heat transfers by conduction, convection and radiation, it seems that higher pressure would make conduction rates of transfer slightly higher and have little effect on the other two.  As the air passes the coils it should expand a little as it is heated.  I'm guessing this would mean that you would move a slightly larger volume of air through your ducts if the blower was compressing the colder air (like a jet engine, only a lot less pressure difference).  I don't have the real world observations/measurements of this, so I was curious about yours.  Not meant in a harsh way, after all, I may be wrong, I am just curious. Rich Hagen

[rotornuts]

I've had the blower on both ends and I didn't notice a difference in tempature transfer (I actually measured the diff. with two thermometers) the best results came from blocking the core of the coil at the exaust end with a 12" long piece of 3" pvc with a cap on it (the same diameter pipe I used to wind the coil). The idea was to force the air to pass through the coil from the inner diameter to the outer diameter. In this configuration I was able to transfer 10 degrees from 130 degree water. Larger diameter copper tubing such as 3/8" and hotter water such as in the 170 degree range would improve this I believe signifigantly. Another thing to note is that It improves heat transfer to run the hot water from the exaust end towards the inlet so the air encounters the hottest water as it is exiting the exchanger.

[deerslayer660]

    in the heating trade we allways put the hot coil in plenem above the heat exchanger of furnace or in a air handler on the push side never put the hot coil or

hot air for that matter to the in side of a blower fan this over heats blower motor

and shortens motor life drastickly i change at least one motor a year for customers

who someone has done something like this for them  george

[nothing to lose]

I like that coil in the flue pipe Idea. I have copper tubing and lots of 4" flue pipe I have no use for. I may try this myself.

Something I was thinking about though maybe would help with the orginal post.

I will be heating water with my wood burner and an outdoor charcoal maker I am building instead of electric, but still hot water anyway.

In my trailer house the floor vents in each room are connected to a duct to an electric furnace in the center of the trailer. (I have Never used it!) I am thinking hot water radiator at the furnace, maybe use the condensor for the central air for this as it's alrady in place and just run hot water through it (I never use it either). Then I have hot air going into the duct at that point. Also run copper tubbing full of hot water through the existing duct, this keeps air hot and provides more heat on the way. Then at the air registers under the floor inside the duct, install small radiators such as used for car heaters, this provides more heat to the air right where it's needed as it exits the duct into the room.

I beleave that would work well. Just a hot radiator in my furnace I don't think would provide enough heat on it's own due to the high volume of air pushed by the blower at that point, but warming it there to begin with and also inline in the duct, I think it should be plenty warm at the room it heats.

Another thing I had thought of is just install the hot water radiators in the rooms and remove the furnace ducts under the floor. Build a little box around the radiators and install a small fan behind it. Just blow the cooler floor air through the radiator to heat it and warm the room, or better yet make a small duct and take the heat off the ceiling sucking it down to warm and re-enter at floor level.

 Sort of like convection heat, forced air, and a ceiling fan all in one. Moving the hot air down from the ceiling helps alot, but my trailer cielings are to low to use fans.

I have had to use thoughs electric baseboard convection heaters before, and although they were a power hog, I liked them as far as heating the house then. Using water in the same way should work well but without the electric bill to follow!

My mother had hot water baseboard heat, worked by convection only (heating the rooms), was good, problem was the electric bill to heat the water!! ANY other way to heat the water and it would have been a good system, and thats a very large house!

Of course any type of hot water heat needs a hot water pump and that's been my hold up, finding one at a price I want to pay. Or even finding them at all, locally we have nothing here.

Anyway I think the water would be better than electric floor heat. First you either have to have electric when you want the heat, or batteries to store it for when you want the heat. Of course if the mills not spining a few days and the grid goes down (does that ever happen ) then that part of the system is down. With water heat a backup heater can be made that needs no real power other than the pump, so in an emergency like power outage you could use wood or propane/nateraul ect.. to heat water and the system is still working. Then a few batteries to power the pump or run a very small gennie as needed.

Floor heating sounds good, but I always think about when things don't work also! Electric blanket type floor heat may be ok off a mill if it works, but I think I'd only want it for suplimental heat and extra comfort and not actually count on it for anything myself. Kinda when it works great it's working, and when it's not, like oh well I don't really need it anyway, type of use.

Too many reasons for power to go out with the grid (and I expect it to get worse in future years, not better), though a mill doesn't worry about those reasons, but then a mill has other reasons to stop also. And does it ever go out on a nice, sunny, calm, warm, dry day?

[sh123469]

Where do you guys find these heating blankets?  I have never seen one available anywhere.

Steve

[Peppyy]

NTL, I have a mobile, (Ancient) home with a full addition and a full basement. I bought an outdoor wood boiler to heat with when I built the addition. I built my own radiant flooring system for the addition heat and simply put a 12"x12" water to air heat exchanger directly under the mobile home furnace. Closed the ductwork back up and hooked a line voltage thermostat to the heating fan. Works great!

.



I used 1/2" Kitec tubing on my radiant floor. Just used a double bubble radiant barrier under the floor joists. Got all the info from the radiant heat institute.

[speedheatus]

Hi there,

I am with Speedheat, and I wanted to let you all know that you can feel free to call us at 800-430-2690 if you have any questions about the under rug electric blanket application.

Sorry...I don't mean to spam, but it seems like we could really help all of you out a lot.

Thanks for your time.

[Roamer195]

If you're going to run any type of heater with wind or solar power, you're better off putting the power into a small heatpump compressor.

You can pull in 3-4kw of ambient outdoor heat for the cost of 1kw input to drive the heatpump.

The trick is to make your outdoor heat-exchangers with lots of surface area. Then circulate a 50:50 glycol solution through those exchangers and across the evaporator on the heatpump. You need to use a system loaded with the organic mix version of R12. Those refrigerants boil at temps around -40F. All the collectable heat is gathered during the "boiling" of the refrigerant(phase change). This means that anything above the boiling point of the refrigerant is an acceptable "source" temperature outside.

If you paint all your outdoor exhangers black and give them a south face they'll collect solar heat and boost the total system COP. This just means that you can collect more heat for the same amount of compressor input power.

[walsdos]

Hi Deerslayer, Don't know if you'll look back to this posting but here goes.... A friend and neghbour has a 20X20 heat exchanger with 24" window fan moving the air through it...Blowing resulted in frequent motor failures, sucking works successfully!!

  I have been thinking about this conumdrum and posit this theory:- Sucking expands the incoming air therefore lowering its temp. simutaneously increasing the differential and ( presumably) increasing the rate of heat transfer twixt air and copper pipes. Upon discharge from the, fan pressure and temp rise resulting in enhanced heating of the surroundings.

 Your experienced blower motor failures I do not dispute having adjusted my own to improve air flow only to find it overloaded and over heating, they must be running right at their limits

[walsdos]

PS Forgot to mention, and ask,my hot water coil ,20X20 with water at 170-180 can't put out enough heat,that is, it can't put out close to what .8 gph of oil can put out.  Any suggestions?