Warning: This is a lengthy read. Some of you know I can write lengthy posts. LOL.
I have acquired some parts and have a plan. This is my first version enabling myself an outdoor unit and investing in the initial plumbing, including high end underground 1 1/4'' lines at about 160'. The heater will be at an easier location rather than the long lengthy process of feeding the current, inefficient, wood furnace in the basement.
I was originally going to build a quick and easy OHF to get me started. I have parts and plans for a second unit, collected as well, to make a downdraft gasser. This 1st unit consists of a tank in a tank build. I have an old school, solid home heating oil tank for the water jacket. I then got a free steal lawn roller that measures 48'' long with a 23 1/2'' dia. Perfect size for a burn chamber. Exhaust out the back and through the back of the heating oil tank. A door and a natural draft air feed.....KISS.
Plan A: I got the burn chamber 2 wks ago, and set it next to the oil tank. I then got to thinking of efficiency. And the brain storming began. My indoor wood furnace is an "updraft gasser." A second chamber at the back and sits horizontally. It's exhausted from the bottom, when the bypass at the top is closed, and fed heated air ,,, it works ok. If there are coals at the opening, it'll burn off most of the wood gas. It'll still smoke some out the chimney though, especially at idle.
Plan B: I got to thinking of longevity of the build. A thin walled burn chamber would burn out/rust out in a few years. Besides, the lawn roller has seam that's been repaired with some weld and there's a pin hole already on the edge from wear. Most likely why it was scrapped. I researched these last year when I first thought of using one. They're made with 12 or 14 gauge and cost $500 at TSC. I was excited to find the one I have until taking a good inspection of it.
I've decided to go with a thicker wall, of the same sized chamber. A friend of mine is an owner of a pipe fitting outfit. I'll most likely get something from him or, find an air compressor tank of a similar size. I have a vertical unit in my garage that needs a motor. I could use that if it's sizeable. I need to stay within a 24''dia. Anything much smaller is going to make feeding cumbersome. Oil tank measures 27'' across giving me an inch and a half on each side with the 24''dia....prefect for water circulation. I'll measure the compressor tank tomorrow. I have a 2nd vertical compressor with a 2 stage pump so, I don't mind sacrificing the other.
Plan C: Involves even better efficiency than the updraft.
I started thinking of secondary air tubes aka tube stove. Initial thoughts were of a sliding baffle plate at the top sitting on brackets, and with some air heated air fed tubes below. Baffle would be 3'' shorter than length of burn chamber. Slide it forwards via connecting rod out the front with a knob, above the door. That would put it in bypass mode. After loading, push the rod in to slide baffle back and exhaust thru front of chamber. I began to think of how much interior space this would use in the chamber. With a 6'' pipe flue coming from the back of chamber complicates space issues further. I want my exhaust to be horizontal and out the rear of the oil tank, easing installation before welding. This way the whole chamber can be slid in thru the front without trying to connect a horizontal flue pipe. I would have to box off a section, at the top inside, for a sliding baffle to work.
Revising this, with an 8'' square mild steel tube, welded on top of the burn chamber cylinder. It would run the full length plus thru the water and approximately 10'' out the back of the tank for 6'' chimney connection. The bottom of this tube would be cut out where it's welded to the cylinder. I'll refer this as the exhaust chamber. The cylinder will have 2 rectangular holes cut out, 8x3'' front and back. Using the cutouts, welded to a connecting rod, they would be positioned 3'' shorter than length of cylinder, and on each end of rod while leaving enough rod length to stick out past the front above the door. Slide forwards to open bypass and close the front hole. Slide back for normal operation.
I'm thinking of one 2'' square air tube about 3/4 the length of the cylinder, and close to the roof. Both sides and the bottom would have 1/8'' holes spaced an inch apart down the length. This single tube would run down underneath the center of the exhaust chamber, isolating it from cooler water temps. Air fed from a pair of 1'' round tubes coming from the face plate of cylinder, below the door. One near each corner. Interior of face plate will be shroud with K-wool blanket and boxed in the heavy gauged sheet. The feed tubes will be on the interior of the chamber, super heating the air supply, and connecting the front of the 2'' square tube. The square tube will fit into the supporting air tubes, while the back will sit in a bracket welded to the roof. Thus a replacement is easy to achieve.
Along with the 1'' of K-wool on the face plate, plans are for 5 lengthwise rows of fire brick on the bottom of cylinder with some sand tossed underneath supporting them. A few more against the rear plate will insulate the coal bed keeping it hot from cooler water. I'm factoring in an approximate sized door of 18'' tall by 16" wide. This will be insulated with 2'' K-wool and encased with 1/4'' steel. I'd like a 2'' round furnace sight glass for viewing the secondary burn. Primary air will enter the sides of the faceplate, and below the secondary intakes, via a connecting tube with a central solenoid operated draft door. Primary air will be delivered with a pair of 2'' square tubes with 3/8 holes drilled on 3'' spacing. These will also be replaceable and sit along the tops of the fire bricks. Of course, there will be some support brackets welded into the oil tank to support all this weight for the cylinder to sit on.
I'm considering extending the primary cross tube out away from the faceplate, allowing room for a secondary air cross tube manually adjustable intake. With this, and the sight glass, I can adjust the secondary for optimal burn at idle. Also considering a draft inducer via chimney, Polar furnace style, over natural draft.
I've calculated water volume to be a little over 200 gals. Cylinder calculates in at 94 gals, not including the smoke chamber. To use the full space of the oil tank, I'm adding an old 30 gal well pressure tank attached to the top fittings. Filled with about 15 gals will leave room for expansion and reach my goal of 200 for heating 4500 sq ft of house.
Goals are:
1. To burn off the smoke at idle, leaving the remaining functions of the water furnace as normal operation.
2, Good water circulation with supply from the bottom front of tank, and return at the top rear.
3. Have a furnace that will last much longer than my original plan. I'll be able to repurpose this to heat my future 48x40' shop and the 800ish sq ft rental house already here. That's after I gather the parts and materials, and build the downdraft gasser for the house. i do have a 420 gal LP tank for that burn chamber......
Again, sorry for the lengthy post. For all you furnace guys and tube stove owners, thoughts and criticisms are welcome.
I have acquired some parts and have a plan. This is my first version enabling myself an outdoor unit and investing in the initial plumbing, including high end underground 1 1/4'' lines at about 160'. The heater will be at an easier location rather than the long lengthy process of feeding the current, inefficient, wood furnace in the basement.
I was originally going to build a quick and easy OHF to get me started. I have parts and plans for a second unit, collected as well, to make a downdraft gasser. This 1st unit consists of a tank in a tank build. I have an old school, solid home heating oil tank for the water jacket. I then got a free steal lawn roller that measures 48'' long with a 23 1/2'' dia. Perfect size for a burn chamber. Exhaust out the back and through the back of the heating oil tank. A door and a natural draft air feed.....KISS.
Plan A: I got the burn chamber 2 wks ago, and set it next to the oil tank. I then got to thinking of efficiency. And the brain storming began. My indoor wood furnace is an "updraft gasser." A second chamber at the back and sits horizontally. It's exhausted from the bottom, when the bypass at the top is closed, and fed heated air ,,, it works ok. If there are coals at the opening, it'll burn off most of the wood gas. It'll still smoke some out the chimney though, especially at idle.
Plan B: I got to thinking of longevity of the build. A thin walled burn chamber would burn out/rust out in a few years. Besides, the lawn roller has seam that's been repaired with some weld and there's a pin hole already on the edge from wear. Most likely why it was scrapped. I researched these last year when I first thought of using one. They're made with 12 or 14 gauge and cost $500 at TSC. I was excited to find the one I have until taking a good inspection of it.
I've decided to go with a thicker wall, of the same sized chamber. A friend of mine is an owner of a pipe fitting outfit. I'll most likely get something from him or, find an air compressor tank of a similar size. I have a vertical unit in my garage that needs a motor. I could use that if it's sizeable. I need to stay within a 24''dia. Anything much smaller is going to make feeding cumbersome. Oil tank measures 27'' across giving me an inch and a half on each side with the 24''dia....prefect for water circulation. I'll measure the compressor tank tomorrow. I have a 2nd vertical compressor with a 2 stage pump so, I don't mind sacrificing the other.
Plan C: Involves even better efficiency than the updraft.
I started thinking of secondary air tubes aka tube stove. Initial thoughts were of a sliding baffle plate at the top sitting on brackets, and with some air heated air fed tubes below. Baffle would be 3'' shorter than length of burn chamber. Slide it forwards via connecting rod out the front with a knob, above the door. That would put it in bypass mode. After loading, push the rod in to slide baffle back and exhaust thru front of chamber. I began to think of how much interior space this would use in the chamber. With a 6'' pipe flue coming from the back of chamber complicates space issues further. I want my exhaust to be horizontal and out the rear of the oil tank, easing installation before welding. This way the whole chamber can be slid in thru the front without trying to connect a horizontal flue pipe. I would have to box off a section, at the top inside, for a sliding baffle to work.
Revising this, with an 8'' square mild steel tube, welded on top of the burn chamber cylinder. It would run the full length plus thru the water and approximately 10'' out the back of the tank for 6'' chimney connection. The bottom of this tube would be cut out where it's welded to the cylinder. I'll refer this as the exhaust chamber. The cylinder will have 2 rectangular holes cut out, 8x3'' front and back. Using the cutouts, welded to a connecting rod, they would be positioned 3'' shorter than length of cylinder, and on each end of rod while leaving enough rod length to stick out past the front above the door. Slide forwards to open bypass and close the front hole. Slide back for normal operation.
I'm thinking of one 2'' square air tube about 3/4 the length of the cylinder, and close to the roof. Both sides and the bottom would have 1/8'' holes spaced an inch apart down the length. This single tube would run down underneath the center of the exhaust chamber, isolating it from cooler water temps. Air fed from a pair of 1'' round tubes coming from the face plate of cylinder, below the door. One near each corner. Interior of face plate will be shroud with K-wool blanket and boxed in the heavy gauged sheet. The feed tubes will be on the interior of the chamber, super heating the air supply, and connecting the front of the 2'' square tube. The square tube will fit into the supporting air tubes, while the back will sit in a bracket welded to the roof. Thus a replacement is easy to achieve.
Along with the 1'' of K-wool on the face plate, plans are for 5 lengthwise rows of fire brick on the bottom of cylinder with some sand tossed underneath supporting them. A few more against the rear plate will insulate the coal bed keeping it hot from cooler water. I'm factoring in an approximate sized door of 18'' tall by 16" wide. This will be insulated with 2'' K-wool and encased with 1/4'' steel. I'd like a 2'' round furnace sight glass for viewing the secondary burn. Primary air will enter the sides of the faceplate, and below the secondary intakes, via a connecting tube with a central solenoid operated draft door. Primary air will be delivered with a pair of 2'' square tubes with 3/8 holes drilled on 3'' spacing. These will also be replaceable and sit along the tops of the fire bricks. Of course, there will be some support brackets welded into the oil tank to support all this weight for the cylinder to sit on.
I'm considering extending the primary cross tube out away from the faceplate, allowing room for a secondary air cross tube manually adjustable intake. With this, and the sight glass, I can adjust the secondary for optimal burn at idle. Also considering a draft inducer via chimney, Polar furnace style, over natural draft.
I've calculated water volume to be a little over 200 gals. Cylinder calculates in at 94 gals, not including the smoke chamber. To use the full space of the oil tank, I'm adding an old 30 gal well pressure tank attached to the top fittings. Filled with about 15 gals will leave room for expansion and reach my goal of 200 for heating 4500 sq ft of house.
Goals are:
1. To burn off the smoke at idle, leaving the remaining functions of the water furnace as normal operation.
2, Good water circulation with supply from the bottom front of tank, and return at the top rear.
3. Have a furnace that will last much longer than my original plan. I'll be able to repurpose this to heat my future 48x40' shop and the 800ish sq ft rental house already here. That's after I gather the parts and materials, and build the downdraft gasser for the house. i do have a 420 gal LP tank for that burn chamber......
Again, sorry for the lengthy post. For all you furnace guys and tube stove owners, thoughts and criticisms are welcome.
