I have been hunting round the net looking for a calculator or some calculation I could understand but not being too bright with these things, have come up without an answer.
What I want to know is what the heat transfer rate from hot gas ( say 500oC) is to water ( Under 20oC) through 2" steel exhaust pipe would be. I don't have the flow rates for the gas nor the water but something rough will be very helpful.
The practical situation is I want to know how many feet of 2" Exhaust tube I need roughly to transfer the heat from my 200Kw/ hr Waste oil burner into water to heat my pool and home. I'd like to get something pretty efficient so If I have a ball park figure I can always add some length to make sure I have enough area.
I realise there are a lot of different parameters but this is backyard engineering rather than pure science so close enough will be good enough in this case.
If anyone could give me an answer in BTU/ Kwh per Ft/ meter for the pipe or point me to a simple calculator or take an educated calculation as to how much length of pipe I need to sink the 200 Kw of energy, I'd sure be mighty appreciative.
I can't help you out with what you request but I can suggest some other things to think about ...
A 2" tube will be highly inefficient at transferring heat like you suggest. The gases in immediate contact with the tube will in fact cool down nicely but what about the majority of gases in the center of the tube ? I suppose you could insert a wavy strip of metal into the tube to induce turbulence to increase the heat exchange rate but how will you clean that contraption. You will have to count on regular cleanings to remove deposits just like any commercial heat exchanger.
Of course this brings me to the question of 'why not use something made for the purpose and rated with the data you want'?
If your water is 20 C you will have a lot of deposits and condensation happening - be sure to have proper drainage and make sure you build in features for easy 'rodding' of the heat exchanger tubing. This is usually done with a gun cleaning brush on a stick and is obviously quite messy. You will be much happier if the heat exchanger is located outside. On a diesel engine that produced less than a tenth of the power you are proposing, I cleaned my tubes every 100 hrs of operation for maximum heat transfer. That could probably be extended to 200 hrs but I didn't run anywhere near that cold. With a heat exchanger you would run cold water into the cold end of the heat exchanger and run it to the hot end. That gives you most efficient heat extraction.
How are you planning to store the heat in order to be able to use it for house heating ? You can run the heat straight into the pool but you are obviously limited to how hot you can make the pool. Because of that limitation, heating the house will be almost impossible unless your house is equipped with in floor radiant heating throughout that is set up for the small temperature difference (lots of tubing in the floor).
The way this is normally done is that you have a heat storage device (pretty substantial for the amount of heat you are generating ... think 1000 gallons as a starting guess). You run that water through your exhaust gas heat exchanger and heat it to just below boiling (assuming it is not pressurized) and you shut the burner off when this is achieved. You use that water to heat the house (I used water to air heat exchangers in my forced air heating system - the heat exchanger is in the air plenum by the regular heater and the regular heater is backup in case of failure of the hydronic system).
You have a water to water separate heat exchanger to heat the pool. Both pool and house heat exchanger systems are thermostatically controlled to maintain the right temperature and the waste oil burner is thermostatically controlled by the heat storage tank.
Any system that is exposed to freezing temperature needs to be protected with antifreeze. Since you don't want to mess with antifreeze in the large heat storage tank, you will want a small, separate hot water loop with antifreeze to go from the exhaust gas heat exchanger to the heat storage tank.
All loops will of course need circulation pumps.
Be aware that although a small exhaust gas heat exchanger can be used if you are dealing with a large temperature difference, you will have to size things totally different when your heat storage tank swings between 70 or 80 and 100 degrees C.
As you can see, things get quite complicated very quickly but you indicated 'efficiently' and a 2" pipe will definitely not cut the mustard. A proper heat exchanger will be able to efficiently deal with the burner energy and pass it on.
Note that I have not approached the subject of draft for the burner as I know nothing about that subject ... but it will need to be addressed, possibly by providing a much larger gas flow cross-section through the heat exchanger than the 2" pipe.
Good luck ! Let us know what the final outcome of the system will be as I am sure that there are lots of interested people .....
Jens is right on, the gas flow as well as the water flow will both try to build laminar flow, and the fluids in contact with the transfer surface will equalize, then act as an insulator to keep heat transfer from effecting the majority of the fluids. Much like the thin layer of water against the skin in a wetsuit acts as insulation to keep a diver warm. You need turbulence in both fluids to increase efficiency, but turbulators in the hot gas stream from the oil burner will make it hard to clean if not thought out carefully. Also as mentioned, you want to try and keep the fluid flows in opposition for best transfer. You also need as much surface area as you can get away with.
In answer to your question, have you tried Engineeringtoolbox.com ? Lots of good heat transfer and heat exchanger info there, such as these tables.
http://www.engineeringtoolbox.com/heat-transfer-coefficients-exchangers-d_450.html
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html That second table the second listing shows a gas at atmospheric pressure to a liquid which probably best describes your project.
Many of their tables list the conductivity in watts/sq meter per degreeC per hour. Most of the tables show the conversion from this figure to BTU/sqft/F/HR. They also have an online calculator to convert the numbers for you.
http://www.engineeringtoolbox.com/thermal-conductivity-calculator-d_857.html
If I were trying to build a water heater, I might try forming a coil of 1/2" soft copper tube into a say 5-6" continous coil. then I would pass the hot gas up the center and shroud in back down along the outside of the coil, with a removable turbulator in the gaps. But since you mentioned pool water with chlorine?, copper is definitaly out as the chlorine will kill it in short order. Next would be a steel coil, like that used in the small oil fired steam cleaners. But that is probably not going to be easilly formed into a coil in the garage...
Good luck.
Or another option might be to use something like 3/4" Corrigated Stainless Steel Tubing(CSST) gas line to form a continous coil. If my math holds up, a coil of this formed around a 6" pipe would use about 1.83' per coil, so a 75' section would form 40 loops with a foot or so pigtail on either end. 40 loops X 3/4" per coil = a 30" X 6" ID tube to blow the hotgas from your burner into, and with an outer ductwork to return the hotgas back down the outside of the coil, you could probably put together a reasonably efficient homegrown collector. Not having the exact ID and OD of the tube to crunch numbers, I can only take a guess that 75' of this stuff will have between 390 and 700 sq/in of transfer area At around $170 for a 75' section, not a horribly expensive experiment. Fittings are redilly available and it is made from 300 series stainless so it should resist pool chemicals fairly well. You can easilly form it by hand around a piece of pipe. And it is available at a bunch of places(HD, Menards ect) although the 75' section will probably have to be ordered. About all you will have to do is strip off the outer yellow PVC sheething with a razor knife. It is only rated for a max of 25 PSI, but if you are just using a circ pump to push water thru it, you should never get anywhere near that pressure... They also make longer continous lengths, so you could have inner and outer coils and direct the gas flow back and forth down the length of the coils to allow more time for heat transfer and drastically increase your transfer area.
I am looking at a similar project to collect heat from a waste oil burner or a chip burner into a large mass storage tank, so I have had a few ideas bouncing around in my head for this:)
Good luck
The ideas of a coiled tube is all nice and dandy but how will you clean it ? Remember that exhaust gases flow in this tube. The corrugated tube is even worse as all the corrugations will fill up nicely with crud. IMHO it has to be a straight smooth tube (single pass) so that it can be rodded clean on a regular schedule.
One thing that has bugged me since I first replied ..... 200 KW and only a 2" exhaust pipe ?????? I can see 20 KW but even then 2" seems suspect if it has any length to it.
Wow this has been a fun question. I thought it odd that such a large discharge of heat, 200000watts/hr through a 2" pipe could possibly be laminar... turns out that the transition from laminar to turbulent flow is between 1ft/s and 2ft/s. Using the discharge temp as my reference I come up with 12.7 ft/s second to discharge 68000BTUs through a 2" pipe.
Because you picked the exact range where exhaust gases change their heat carrying capacity and density very drastically, I didn't get the length of pipe. BUT....and this is the big one....Can your burner push the exhaust out at 13 ft/s? If not then this question changes drastically. We need to know if your fan will be able to force the gas into the 2" restriction. If not then, we have to use bigger pipe. You have to move 40ft^3/s to realize the 68k BTUs you want. If this was an enigine, it would be no problem because they are positive displacement pumps, but if its a squirrel cage, it might gag on the little pipe and force smoke out the door..hate to say this but, I need more details.
This one gets my little gray cells bouncing off each other too.
I think I'd convert to 3 inch copper pipe. If I were using the 3 inch (or 4 inch if I scored a deal) I'd beat it up a little with a soft stroke sledge hammer. Or two 2 inchers with a cross fitting in the middle to mix things up.
Are you going to pump the water past or rely on some sort of thermosyphon?
Casey
QuoteMuch like the thin layer of water against the skin in a wetsuit acts as insulation to keep a diver warm.
Really?
OMG, I flubbed a conversion...I am getting some kind of crazy gas velocity...1834 ft/s to move 40ft^3/s through 2" pipe... maybe salamanders do this, or a jet...
Anyhow, the 2" pipe is losing 49 BTUs per foot starting at 932F but gradually transfers less and less as the gas inside cools. By the time its just above 212F its transfering 11BTUs per foot. I would say at that point it would be time to pull the pin and dump the gas before it condenses the steam (and acids).
BPJ
Ok, so I ran into the intergration problem between 49BTUs/ft and 11BTUs/ft..and I am afraid...seeing as I am afraid to intergrate...I would plug and chug with a spread sheet using smaller and smaller intervals... but before I do that, is there anyone who could possibly remember which intergal that one was? Is it like the efficiency of a cooling fin? I think I could answer the question for the guy, by assuming the velocity is transitional, and having the intergal solved...anybody? Buehler?
BPJ
Jens, the water would flow thru the corrigated pipe. The hot gas would pass thru the area formed by winding the tube around a mandrel. Visualize a large spring... The area that needs to be cleaned would be rather large and accessible by a chimney brush initially. The corrigations being perpendicular to the tubing length, when wound around a form and shaped/coiled into a larger tube, would line up parallel to the axis of the larger formed tube. How it is shrouded would determine how difficult it is to clean. If the shrouding can be completely removed, it might not be all that bad, perhaps even doable with a pressure washer... I guess I won't know till I build one:)
Like this:
http://www.ebay.co.uk/itm/KARCHER-HDS-601c-ECO-STEAM-CLEANER-BOILER-HEATING-COIL-/270504320385
The outlet of the Burner ( which I just went and measured to be sure) is 40mm. You can see a vid of the thing Running here: http://www.youtube.com/watch?v=v0CEk_f0N7E
In the vid the elbow sitting over the top of the thing is 4" to induce some secondary air. I did another vid of it the other week running horizontally and flat out at about 240Kw/hr and the thing does indeed sound like a Jet. Hopefully blowing the heat through a pipe right on the outlet and surrounded by a water jacket will quiet the thing Significantly as its far too loud to be running for practical purposes as it sounds in the open.
I am trying to build the HE as cheap as possible which is why I thought of using the exhaust pipe. I have rung some muffler shops and they tell me they don't have benders that can wind the pipe into a coil so I was thinking a loop ( Curved ends, straight in the middle) or a zig zag would do. I want to try and enclose the fire tube in a 44 gallon drum and pump the water through that.
I thought the bends and direction changing might induce some swirl in the gas and I was thinking to dent it a bit with a hammer or drill a hole every so often and weld in a bolt so the gas flow is disturbed and makes better contact of the hot gasses with the pipe. Exhaust Pipe here comes in 6.5m ( 20 ft?) lengths so I was wanting to get some idea of how many lengths I'd have to use to transfer the majority of the energy into the water which I want to jacket the pipe with.
I don't envisage cleaning being a big problem. The output of the burner is very clean and produces no smoke or carbon buildup due to the thing running an oversupply of air. I was also going to add a second air inlet near the top of the burner to make use of some of the excess air the blower is generating and ensure the cleanest burn possible. Even if I do get some buildup, It wouldn't be hard just to take off the burner and flush the whole thing with water and maybe a bit of caustic if need be.
As I thinking of building the thing, also not much problem just to run it dry and burn any buildup out as it will all be welded metal so nothing to melt or burn.
I have another burner of a different design which I tried running in a 44 gallon drum with a car radiator on the top and an fan sucking through it. I took out both ends of the drum and sat it on bricks so as to try and get some cold air mixing and lowering the gas temp. Even though the radiator was rated for nearly double the output I was creating, I couldn't get it the gas temps low enough and it started melting the plastic fans on the cold side of the radiator and seemed to damage the fins on the rad as well somewhat. I thought something that was impervious to overheating would be the way to go hence the pipe idea.
I don't like the idea of coils in the gas stream much as whatever you put the assembly in is always going to have more surface area of the container where the heat can escape, insulated or not, than the area of the tubing you want to pick up the heat. Plus in this case, when using something like 1/2 of 3/4 tubing, you'd need 100 miles of the stuff to absorb that much energy and copper pipe is BLOODY expensive here.
I'm very open to different ideas with this as long as it's relatively cheap and simple for me to build.
It seems I can build burners with no trouble at all, I have lots to learn about heat exchangers though which will allow me to put the heat to the work I want it to do!
Quote from: Ronmar on April 19, 2013, 12:02:03 AM
Jens, the water would flow thru the corrigated pipe. The hot gas would pass thru the area formed by winding the tube around a mandrel. Visualize a large spring...
Ahhhh, I see ..... yes, that would easily clean with a pressure washer but I am not sure how efficient it would be. I could see having a loose (removable) baffle type thing in the middle and a shroud on the outside and that could work very well and be extremely easily cleaned. Cool (hot) idea :)
Quote from: glort on April 19, 2013, 01:13:51 AM
The outlet of the Burner ( which I just went and measured to be sure) is 40mm. You can see a vid of the thing Running here: http://www.youtube.com/watch?v=v0CEk_f0N7E
In the vid the elbow sitting over the top of the thing is 4" to induce some secondary air. I did another vid of it the other week running horizontally and flat out at about 240Kw/hr and the thing does indeed sound like a Jet. Hopefully blowing the heat through a pipe right on the outlet and surrounded by a water jacket will quiet the thing Significantly as its far too loud to be running for practical purposes as it sounds in the open.
I am trying to build the HE as cheap as possible which is why I thought of using the exhaust pipe. I have rung some muffler shops and they tell me they don't have benders that can wind the pipe into a coil so I was thinking a loop ( Curved ends, straight in the middle) or a zig zag would do. I want to try and enclose the fire tube in a 44 gallon drum and pump the water through that.
I thought the bends and direction changing might induce some swirl in the gas and I was thinking to dent it a bit with a hammer or drill a hole every so often and weld in a bolt so the gas flow is disturbed and makes better contact of the hot gasses with the pipe. Exhaust Pipe here comes in 6.5m ( 20 ft?) lengths so I was wanting to get some idea of how many lengths I'd have to use to transfer the majority of the energy into the water which I want to jacket the pipe with.
I don't envisage cleaning being a big problem. The output of the burner is very clean and produces no smoke or carbon buildup due to the thing running an oversupply of air. I was also going to add a second air inlet near the top of the burner to make use of some of the excess air the blower is generating and ensure the cleanest burn possible. Even if I do get some buildup, It wouldn't be hard just to take off the burner and flush the whole thing with water and maybe a bit of caustic if need be.
As I thinking of building the thing, also not much problem just to run it dry and burn any buildup out as it will all be welded metal so nothing to melt or burn.
I have another burner of a different design which I tried running in a 44 gallon drum with a car radiator on the top and an fan sucking through it. I took out both ends of the drum and sat it on bricks so as to try and get some cold air mixing and lowering the gas temp. Even though the radiator was rated for nearly double the output I was creating, I couldn't get it the gas temps low enough and it started melting the plastic fans on the cold side of the radiator and seemed to damage the fins on the rad as well somewhat. I thought something that was impervious to overheating would be the way to go hence the pipe idea.
I don't like the idea of coils in the gas stream much as whatever you put the assembly in is always going to have more surface area of the container where the heat can escape, insulated or not, than the area of the tubing you want to pick up the heat. Plus in this case, when using something like 1/2 of 3/4 tubing, you'd need 100 miles of the stuff to absorb that much energy and copper pipe is BLOODY expensive here.
I'm very open to different ideas with this as long as it's relatively cheap and simple for me to build.
It seems I can build burners with no trouble at all, I have lots to learn about heat exchangers though which will allow me to put the heat to the work I want it to do!
Woaaa .... way out of left field for that one. A most impressive burner indeed, totally different than what I had in mind! ... and very cheap to build!
Of course what we are seeing here is probably less than 1% efficient and probably requires constant supervision but definitely interesting!
Running the exhaust through a bunch of elbows in a 45 gallon drum and at the speed of gas flow we are seeing would probably result in lots of turbulence and laminar flow would not be an issue.
I suspect (but don't know) that no matter how you slice this, efficiency will not be stellar but with input energy being free or very cheap, this should not be a big concern.
If I were in your shoes, I would first try and establish what happens when you put a significant amount of pipe on the exhaust. Will the burner still work as well ? What will the noise be like ? I would also contemplate what Ronmar posted - introduce the exhaust into the bottom of a 45 gallon drum and take a soft 3/4" copper pipe which should be easily bent in a big loop, maybe use a 30 gallon drum on the inside to plug the central hole but fill it with water to absorb additional energy.
I am not sure if I am describing it well and I don't know how to do diagrams ... let me try again ...,
Take a 45 gallon drum, forget the elbow on the output of your burner, set it in the middle underneath your drum, and blow the exhaust straight up into the 45 gallon drum. Set a 30 gallon drum into the center of the 45 gallon drum on some fire bricks, maybe reinforce (welded plate?) the bottom of the 30 gallon drum that is receiving direct flame. The exhaust gases will hit the bottom of the 30 gallon drum (that is filled with water) and will deflect to the sides and forced up through the gap between the 40 an 45 gallon drums. BTW, I do not know how the diameter of the two drums compare and if the gap is suitable, Anyway, to continue, you have one or more large coils of soft copper curled in the gap with water running through it/them and the exhaust of the burner running on the outside of the copper pipe in the gap. I hope that makes sense .....
The water in the 30 gal drum could be preheated water that then runs through the copper pipe and on to your storage facility and back into the 30 gallon drum. The 30 gallon drum should be closed to avoid evaporative losses. There would be very little if any concern with exhaust back pressure because the effective exhaust diameter would be huge. Additional efficiency could be achieved bu insulating the outside of the 45 gallon drum or somehow recovering heat from this surface as well but that could be added later on. If necessary and deemed worthwhile, the hight of this contraption could be doubled to two drums high bringing the noise and any exhaust smell higher up as well as increasing efficiency at the loss of ease of cleaning.
The more I think about this the more I like it enormous possibilities .....
One could add fins on the outside of the copper tubes in the colder areas (top) to absorb more heat. These are, I believe, commercially available preformed and slide over the pipe and ran be (hard/soft?) soldered to the pipe. Don't know how cleaning would be effected.
Wow, so many thoughts, so little time to write them all down ...
Hi, thanks for the video...the easiest thing to do with your technology level is to find a used boiler, or gas fueled water heater and run the burner into the boiler's firebox. Failing that...use or make some sort of water tube boiler. Go look at the heating system in a steam pressure washer. The fire plays over coils, in which, the water circulates.
With what I see on the video, your problem is going to be welding all that pipe together and not having it leak. So look for something already built.
BPJ
Glort
That is why I was suggesting the CSST. It is used for gas installations all over the world and is fairly inexpensive. A 75' piece is $170 US and will form a coil 6" in diameter and 30" long(40 coils). A 250' section is around $390 us, and would allow you to form a multi layered coil. In answer to your outside surface area being a large heat loss, you simply wind a final coil as the outside then insulate around the outside of that. A 250' section would get you a 24" long heatex(32 coils) with 3 layers of coils one inside the other. One with a 6" ID, the next with a 9.25" ID and the last with a 12 3/4" ID. The hotgas would pass down the center of the innermost coil, then be turned back down between the first and second coil to pass alsong that passage. Back at the starting end it would again be turned back to pass bewteen the second and third coiled tube, with the third coil forming the outer layer along with an insulated skin. This would keep the hotgas surrounded by water.
I suggest the coil along the lines of the steam cleaner boilers. There is a reason they do this as a continous tube. Welded structures don't heat cycle well. Shell and tube boilers are not welded, they are swaged to allow for expansion and contraction of the structure. When you weld, the tubes will grow in length when heated and wear on that weld hardened union and cause cracks and leaks. Using coiled continous tube, the tube coil free floats and can expand and contract at will without failure. If my math is correct, 250' of CSST should be around 112 SQ/FT of transfer area...
Thanks for the very helpful input. Certainly plenty to think about and investigate.
Jens,
I think I understand what you meant with the drums.
I help a friend make Boiodiesel half a dozen times a year and part of that involves heating and drying the oil before processing. My friend used to cau 44 gallon drums in half and sit the 20L drums veg oil comes in here on top of the fire. Eventualy they would boil and the water would be driven off. Generally took an hour for an average oil/ water quality drum.
Looking on the net I got to thinking about the sides of a drum being a much larger area then the bottom. I got a 60L drum, cut a hole in the bottom so the wood for a fire could be put in there and drove a bit of rebar about 1/3rd the way up so the 20L drum could be inserted and suspended. I rested it out and could get a drum of oil to boil in about 5 min flat and the thing dry in about 20. It was a massive difference in speed and efficiency.
I took this engineering marvel over to my friend and he laughed..... Right till the time he saw how much faster the oil boiled and the heat going into it. We made 3 similar boiler drums in the end which was as many as we could keep up with.
As production volume increased, I made the burner in the vid so we could go back to the brute force method. We are going to get another drum, take the ends out split and open it up it to encase the Middle drum to0 make that more efficient. I can boil a drum of oil in 17min now, it would be awesome to achieve that in 5 Min!
Efficient it's not ATM but it serves 2 purposes. Between my friend, his sons and all their girlfriends, they service about 8 vehicles at his house so it generates quite a bit of used engine oil. He always was running to the tip to dispose of it and they only allow so much per trip. Now we use it to fuel the burner which saves him going out of his way ( well and truly) to take it to the disposal place and drys and heats the oil for Bio making.
Ronmar,
I googled the CSST and can only see one place listing it here but I'm sure it's available more widely. I'll ring around during the week and see what I can find and how much it is. I also see a listing for galvanised instead of stainless which might be good for testing things out initially at a lower cost. If it works well I'll use the gal till it fails and then get the stainless and build in whatever improvements become obvious.
Failing that I have had one more brainwave.
I'm thinking of a central Square tube running say 3/4 the way up the drum. From each side of the square tube I can cut holes in it and weld a bit of round tube on which has been pre bent with a simple Bender at 90o to come out from the central tube wand using multiple round pipes, to form a branch structure much like a tree. I'm thinking if the pipes come out and then go at and angle ( say 45o)rather than straight up, that may help efficiency as well. I may also be able to put some staggered bend in the pipe, small angles and straight sections to get the pipe to run round the drum a bit making for less holes and welding and greater surface area.
I hope I can get the stainless or gal corrugated pipe cheap enough because I could use a smaller, say 1" diameter of that and weld it to a branch to use say 4 separate pipes to get the flow and it would be so easy to coil inside the drum and surround with water. I see on the info I found they say it's good for exhaust use and withstands 500oC with no problem so in this application where it is kept relatively cool with the water on one side. it should have no problem standing up to the Mega blowtorch. :0)
As a side note, I have looked at so many Vids on Youtube and there are a Myriad of waste oil burners on there.
It's also apparent that while a lot of these buners work, they are really only good as shed heaters because the way they work makes putting the heat to work other than air heating, a very difficult proposition.
Quote from: Dualfuel on April 19, 2013, 07:13:18 AM
Hi, thanks for the video...the easiest thing to do with your technology level is to find a used boiler, or gas fueled water heater and run the burner into the boiler's firebox. Failing that...use or make some sort of water tube boiler.
Yeah, That was my first thought... about 3 years ago. I wanted to get an old gas pool heater which is about the most common type boiler here and pull out the burner and stick in the oil burner. I could fire the flame down a length of tube with one end blocked with holes drilled in it to spread the heat and replicate the gas burners more closely.
Unfortunately about the closest I have come to finding an old gas boiler of any kind like that is to get the actual Heat exchanger out of one but it takes weird Diameter pipes with special Expensive flanges and is heavy as hell. Building a housing for it would take a bit and then there is the problem of insulating it.
If I come up dry on all the other concepts, I might have to revisit that.
Quote from: glort on April 20, 2013, 02:38:11 AM
I also see a listing for galvanised instead of stainless which might be good for testing things out initially at a lower cost.
Just a couple of cautions here:
Galvanization burns off at a pretty low temperature producing a TOXIC white gas. It is extremely important that you keep this in mind while welding and in your test burners. I don't foresee a problem with water on the inside but it could theoretically form large air bubbles allowing excessive localized heat.
Welding galvanized stuff usually makes a mess of the weld unless the galvanization is removed. Exhaust components are usually aluminized giving rust protection and the ability to weld stuff together.
Danger Will Robinson! Danger! Danger!
Finally got around to looking at your video, that is a pretty impressive burner. I am using a babbington burner to heat my garage. Here is a vid of the first one I built.
http://youtube.com/watch?feature=plcp&v=3ACukFExR4I
I made up a welded finned pipe(fins on inside and outside) about 6' long with a 6" ID. That sets inside an outer tube. The burner end of this thing sets in my garage. I run the burner thru the inside pipe and pump outside air in thru the outer pipe with a squirrel cage blower. I get a large volume of 250F air pumped into the garage. Heats it up from 30F in about 20-30 minutes.
I am in the process of desiging us a new ICF home with radiant floor heat. That is why I have been looking into ways to heat water with this burner or the output from a chip/pellet burner.
That's a Nice, neat and practical design.
My mate had one for heating his oil . Just the dregs of the Bio and the compressed air Feeding into A copper T piece and another bit that was flattened to make a spray Nozzle. He used to blast the flame through an old gas water heater that was lying on it's side. We calculated it was putting 33Kw of heat into the oil he was pumping through which wasn't bad.
The thing I don't prefer about Babingtons is that you need a compressor running to feed them. My mate wore out a couple before I came along with the fire drums then the oil burners.
I have always had this thing about heating my pool with waste oil so always was looking for high output designs and long run times. I am looking at smaller ones now but am actually finding them harder to build and operate than the big ones.
I have got one little one going, I put controls on the air as well as the fuel so the air can be stopped down to prevent overcooling of the burn chamber which brings an end to the show on my designs.
One thing you may care to look at one day is doing away with the compressed air on your design once its running. Heat it up as you would normally then if you lengthen the output tube and preferably make it a heavy gauge and then put some bits of pipe laying inside of that, they will act like glow plugs and you can just squirt the oil in and used forced/ blown air. It vaporises the oil on contact with teh hot bits of metal and will self sustain very nicely. Quieter and less energy to use a blower than a compressor.
I did one that had an internal switchback. It was a beast. Had to warm it up on gas then switched to oil and off it went. The more you turned it up ( slowly) the hotter and better it ran. I never got the thing to full tilt. I ran it connected to an electric leaf blower one time and had the oil drum on the shed roof but it needed more fuel pressure as it was making too much resistance to the oil to flow quick enough. I must drag that thing out one day and fire it up using a small diaphragm pump.
I'm very interested in Different burner designs, maybe there could be a section for people to post different ones up. Would be real interesting to see them.
Mine dosn't hardly use any air. I am injecting the air thru I think a .015" hole at 25 PSI. My compressor does not run constantly as the airflow is so small. It might cycle and top off the 25 gallon tank once every hour or so maybe? The air IS what atomizes the oil that flows down over the nozzle hole, so I don't think I want to do away with it. In fact, air is the only thing I use to power/control the burner. I have a 3 gallon pressure tank from an old air horn system that I put my fuel in. It is stood on end and the outlet at the bottom is tied to the burner with a 1/4" ball valve for on/off control. I apply very low pressure compressed air to the top of the tank(less than 1 PSI typically) with a regulator. I regulate this air pressure to control the burner output.
I didn't want a tall chimney on this heater since I wanted to be able to move it fairly easilly(it is pretty heavy). Since the heatex is so long and the chimney on the end is only about 18" tall, I added a 3" computer fan in to apply a little bit of draft air at the burner end. It is all run thru a plate that the garage door closes down over. I will put up a pic of it later...
Obviously you guys are approaching the moon and I'm still pretty fascinated with the teeter-totter.
Too much power to feed an on-demand water heater? Maybe ducted back a couple of feet?
All that heat is coming from WVO and a high volume fan?
Casey
Here is my garage heater and fuel tank. The smaller pipe down in front is the added draft air coming from a 3" computer fan mounted at the plate.
(http://i270.photobucket.com/albums/jj85/rmarlett/th_a72284403dab1f710d58a31779e023d2.jpg) (http://s270.photobucket.com/albums/jj85/rmarlett/?action=view¤t=a72284403dab1f710d58a31779e023d2.jpg)
Here is the outside end with about an 18" chimney. Hot gas passes up the inner tube and turns up thru an elbow and out the exhaust. Fresh outside air is pumped in around the outside of the heatex pipe and exits around the burner.
(http://i270.photobucket.com/albums/jj85/rmarlett/th_8276d5e276604a9cec050c61d43a5078.jpg) (http://s270.photobucket.com/albums/jj85/rmarlett/?action=view¤t=8276d5e276604a9cec050c61d43a5078.jpg)
There are two regulators mounted on top of the tank. One where the air quickfitting is, gets me 25 psi for the burner nozzle. The larger silver one is a lo pressure reg that gives me my fuel pressure air. With motor oil 3/4 psi has been about the sweet spot. The fuel exits at the bottom passes along the pipe and thru the coils located in the hot air stream where it get preheated before streaming down over the nozzle. For lightoff I preheat the coils and burner body with a torch, then put the torch in thru a access cover and turn on the fuel valve and away she goes... I startup the outside air blower after about a minute so it only blows warm air. After a run it continues to blow warm air for about 10 minutes after I turn off the burner.
(http://i270.photobucket.com/albums/jj85/rmarlett/th_27ffa0b5ae311b830ec4acd9c7c51e8b.jpg) (http://s270.photobucket.com/albums/jj85/rmarlett/?action=view¤t=27ffa0b5ae311b830ec4acd9c7c51e8b.jpg)
Thanks for the pics and Info. That gives a thickhead like me a much better idea.
That is a very original design. Never seen anything like it before. Also nicely efficient.
I was also under an incorrect impression with the Babbington. I had no idea they could use that little air. It makes a big difference to my impression of them. Going on that, I can see how such a system is very practical.
I wonder if it would be possible to generate a worthwhile amount of air pressure for one ( even a small one) with one of those mega Fish tank air pumps?
Quote from: LowGear on April 21, 2013, 02:32:39 PM
Obviously you guys are approaching the moon and I'm still pretty fascinated with the teeter-totter.
Too much power to feed an on-demand water heater? Maybe ducted back a couple of feet?
All that heat is coming from WVO and a high volume fan?
Casey
Comes from years of wasting time mucking round when I should have been doing more purposeful things in my case.
The burners I make now are technically Illegal in my part of the world. You have to have burners inspected, certified and licensed if they do over 500,000btu.
I can triple that pretty easy. :0)
Burning oil and burning it clean aren't that difficult when you work out a few simple things.
First one for me was heat. In my non atomised designs, you have to get the oil Output Hot and keep it that way so it changes from liquid to a gas.
You can't just do that in a coiled bit of 1/4" copper pipe, it will foul up in minutes from the residue any waste oil will leave behind. You have to do it in a chamber where it will either be blown out as invisible ash or burned out as carbon.
Second one was air and secondary air.
Anything will burn clean if it is mixed with enough air. I was Burning some styrofoam the other night as a test and got that to burn clean. Sure burns hot as well.
You either have to supply an excess of air without overcooling the fire or you have to supply more air after the initial fire.
A lot of people thing of Burning oil as like burning tyres in the open, it just dont work that way. That said, I have often done the mental arithmetic of a tyre burner. There would be a lot of heat in that and shouldn't be hard to build a burner you loaded once a day and kept your home plenty warm for 24 hours.
If you built the thing so you could put them in whole there would be no processing like splitting wood and there would be endless sources giving you more fuel than you could possibly use.
Done right, there wouldn't have to be a bit of smoke or small though.
I have seen a load of different ways of burning oil and I have also seen some designs that appear more prevalent in different localities than others. The Japanese seem to have a design that is popular and the Russians another from what I have looked up. They all work, just in different ways. Some are passive, no external energy required, and others are active with fans or compressed air etc.
To me the trick is getting the heat to do the work you want.
I have seen endless vids where people burn the oil out in the yard, Putting it to work in a practical, safe fashion as Ronmar has is something quite different.
Burners can be simple as hammers as well.
I have one I use in My wood fire Pizza oven when I'm not allowed to burn wood.
The thing is literally a 2" bit of exhaust pipe with a 1/4" Bit of copper pipe coming through the side. It's just stuck through a hole I drilled in teh 2" pipe. I use a small blower form a car to power it.
I light this up on gas and have it aimed a a few bricks strategically placed at the end of the burner. After about 5min when things get hot, I slowly turn on the oil and watch the flame build and when it's running hard after a couple of Min, I turn the gas off. The bricks glow red ( near white if you crank the thing and leave it and hour or so) and evaporate the fuel. By the time it's really cooking, the oil seems to take 3 forms.
Some light fractions burn like a gas as soon as they hit the hot tube and burn with a blue flame. The next phase turns to whit vapor and ignites soon after it leaves the burning tube and the 3rd phase is liquid oil which burns on contact with the hot bricks. I see the exact same phases when running my turk style burner.
The thing is, this Burner is a steel pipe with a hole drilled in the side and a bit of copper pipe inserted to feed oil into the thing.
I couldn't imagine anything simpler except if you fed the oil from the end and didn't have to drill the hole! :0)
For me this all really comes down to going against the grain and making good use from a free waste product.
I get a lot of satisfaction out of that.
Quote from: glort on April 21, 2013, 11:23:11 PM
Thanks for the pics and Info. That gives a thickhead like me a much better idea.
That is a very original design. Never seen anything like it before. Also nicely efficient.
I was also under an incorrect impression with the Babbington. I had no idea they could use that little air. It makes a big difference to my impression of them. Going on that, I can see how such a system is very practical.
I wonder if it would be possible to generate a worthwhile amount of air pressure for one ( even a small one) with one of those mega Fish tank air pumps?
I have heard of people running them on old reefer compressors. A fish tank compressor might work as it is a pretty small volume of air...
There will be less sooting problems if the water leaving the exhaust heater exchanger is about 205F. Exhaust's first contact with the heat exchanger should be adjacent to where the hot water is leaving the heat exchanger.
Quote from: Ronmar on April 21, 2013, 12:57:45 PM
Mine dosn't hardly use any air. I am injecting the air thru I think a .015" hole at 25 PSI. My compressor does not run constantly as the airflow is so small. It might cycle and top off the 25 gallon tank once every hour or so maybe? The air IS what atomizes the oil that flows down over the nozzle hole, so I don't think I want to do away with it. In fact, air is the only thing I use to power/control the burner. I have a 3 gallon pressure tank from an old air horn system that I put my fuel in. It is stood on end and the outlet at the bottom is tied to the burner with a 1/4" ball valve for on/off control. I apply very low pressure compressed air to the top of the tank(less than 1 PSI typically) with a regulator. I regulate this air pressure to control the burner output.
I didn't want a tall chimney on this heater since I wanted to be able to move it fairly easilly(it is pretty heavy). Since the heatex is so long and the chimney on the end is only about 18" tall, I added a 3" computer fan in to apply a little bit of draft air at the burner end. It is all run thru a plate that the garage door closes down over. I will put up a pic of it later...
Ronmar,
If you don't mind my asking, how do you manage the "runoff" ?(a better term doesn't come readily to mind) of the excess oil from the Babington nozzle?
That has always been the hitch that stopped me from building a Babington burner. IIRC years ago as a boy, the article ran in either Popular Mechanics or Popular Science, of Mr. Babington and his nozzle - his first was a cast iron shift knob with a slit hacksawed in it.
Ron.