Corn buring furnaces

John R. Hall

A company in Michigan makes them. It costs about $600 a winter to heat a home using the corn, usually harvested from two acres of corn. Check out www.ja-ran.com. I'd be happy to hear your feedback.

Greg Swob

We have an area farmer

who sells corn stoves and another who just began selling corn boilers. The latter is heating an indoor pool and the pool room with the boiler and he is his only customer to date. I'm not sure if the installation is complete yet. We were only in on the heatloss calc and helped with piping, heat exchanger & circulator layout. We feel there is little chance he can make this thing pay out. Except that he grows a few thousand acres of corn & what bushels the boiler will use will not be missed, nor will it be considered as part of farm income (he and the accountant have this part figured out). Very pricey appliances. Will advise if and when we get feedback. Greg

Mark Eatherton1

What happens...

if you use popping corn?

A friend of mine just installed a corn stove to offset his propane bill. Says it works like a champ!

ME

Steve Ebels

That greenhouse job

If it happens, that will be a good test. 18,000 sq.ft. under "glass". Actually a double wrap of polyethelene plastic.

The owner visited a HUGE greenhouse in Ontario and took pics of how they heated that place. They have 3 Cleaver Brooks that double as truck garages in the summer months, fired by nat gas. (yes they are that BIG) Water from these is circulated by 8, 20hp Taco's out to the distribution side. What they use for heat emitters was really quite neat. They have no fan coils at all. the heat is strictly convection and radiant based. Down each row of plants they have a pair of 2" steel pipes on "chairs" about 6" off the cement floor. The hot water is circulated through these. I don't know how many miles of this are in the place, which is approaching 70 acres. All of the pipe is welded and they use them as rails to run their picking carts down each aisle.

This is what my green thumb guy wants to do also. What I'm debating at this point is how to control the heat in the greenhouse using this type of system. It would be no problem with a regular boiler, especially a big condenser, to just ramp the temp up and down with the demand from an indoor control. Outdoor reset would definitely not work because of huge and instantaneous solar gain during the day. The point to ponder here is how to do it with these corn boilers he wants to use. They have a minimum "idle" setting that must be maintained or the coals will die out. Bad news if that happens. (can we say dead tomatos?)


I can lay out the piping to get close to a 20* drop but that still equates to about 120 GPM at a 1.2 million btu heat loss. That makes a mixing valve controlled by an indoor sensor very expensive. I haven't found one yet but I'm thinking I'd need a 6" valve.

The other option, and I don't even know if such a thing is out there, would be a variable speed drive for the system pump. This would ramp the system flow up and down to meet demand from the building. This was suggested to me by an engineer. (go figure) His thought was that you could maintain a constant water temp and modulate output by increasing or decreasing flow to the piping.

If I could get the guy off the corn thing, I'd set him up with a fully modulating Vertomat and vent it right into the greenhouse to provide CO2 for the plants. They burn with low enough CO to do this safely, with monitors of course. Let it modulate firing rate and water temp based on demand. Viessmann says they can furnish a control to do this.
That, to me, would be the bomb!!

Mark Eatherton1

Variable speed pump controllers...

B&G just brought theirs out, and Honeywell also has one ready for market. See, if you build it, they WILL come.

ME

hr

Generally

they use corn that is unfit for consumption, as I understand it. Corn can mold and go bad under certain storage conditions, this is what you want to burn. Not the good stuff we, or the livestock, can eat!

Wonder what happens when you burn "bio-corn' that genitically altered stuff they grow these days. Maybe that's where LD comes from

I did a web search and a few corn burners come up. Try one of the sites for a connection to a person actually using one. I'd be curious also. Seems very similar to pellet stove techonolgy. I'd like to see pellet boilers. Tons, mountains in fact, of saw dust and other wood working byproducts in my area where most hardwood comes from!

hot rod

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Boilerpro_3

Variable speed drives for BIG pumps

I believe B&G has what you might want I was just looking at two 5 hp series pumps, that I believe are grossly oversized for the system and it was suggested to use a variable speed drive to control them. I believe the drive accepts a standard 4 - 20 ma signal or a dc signal that is available on the Tekmar mixing controls. You could just use a couple of tekmar 361 injection pump controls with 2 NRF-33's each, they give about 70 gpm flow for each tekmar control and are under the maximaum amperage for the control.

Boilerpro_3

Variable speed drives for BIG pumps

I believe B&G has what you might want. I was just looking at two 5 hp pumps that I believe are grossly oversized for the system and it was suggested to use a variable speed drive to control them. I believe the drive accepts a standard 4 - 20 ma signal or a dc signal that is available on the Tekmar mixing controls. You could just use a couple of tekmar 361 injection pump controls with 2 NRF-33's each, they give about 70 gpm flow for each tekmar control and are under the maximaum amperage for the control.


Boilerpro

Lloyd Nichols

Wood pellet and corn boilers

I have been using a wood pellet and corn fired boiler made by Baxi (formerly HS Tarm) for the past three years. Last winter it took three tons of wood pellets to heat my 2300 sf
energy efficient home with a 55,000 btuh boiler. During a very cold run of 14 days last February I averaged 65 lbs per day. During "normal" winter weather I average about 40 lbs per day. The hopper holds 250 lbs so I can go several days between fillings. These boilers work very well on all grades of wood pellets (hard wood, soft wood, low ash and high ash) and they work well with any grade of shelled corn. There is more residue when corn or high ash wood pellets are used but with premium (normal) grade wood pellets it only takes about a minute or two per week to remove the ash. These boilers will spoil you they are so easy to use.

Available sizes and technical details can be seen on the website www.woodboilers.com. These European stoker boilers are new here in North America but they are starting to earn a good reputation amoung a a small but growing group of owners. Wood and biomass boilers are not for everyone but
high quality units offer a good earth friendly heating
alternative to people who want to use renewable energy.

hr

You may need some large buffer tanks, and

Lochinvar now offers them. RVU series available in 120- 500 gallon with 3 to 6" tappings. The cut sheet has a Quick Sizing table. I'd be glad to fax coppies if you need.

That is always the challange with solid fuel burning equipment. You really want a good hot burn, so well insulated BTU storage is best handled with large tanks.

Could you use injection mixing and stay away from large (expensive) mixing valves?

hot rod

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Steve Ebels

Fax number

Thanks Hot Rod. My fax is 240-371-3041 and I'd be interested in seeing that data. I haven't done but a few injection systems, all standard size residential. How big can you go with injection?

If the guy goes with this and I change the water temp to regulate the heat output, I would have to be able to go from nothing to around 170-180*. My meager common sense tells me that to get those high temps the injection pump would have to be able to dump all of the heat available into the main loop. Can this be done?

Colin

Corn/bio-mass boilers

Steve, so far we've only installed one. The Mfg. tells me it's a 100,000 btu which is close to the calculated load but w/ the total radiant-ly heated building (one zone) we can only get 10 to 30%injection pump speed before shutting down the injection pump because it causes to low of boiler return temp (130) and my concern is condensation.

The Mfg. tells me they have a way to get 160,000 out of it but we hav'nt gone that far yet.

The other problem we've encountered is as Hot Rod mentioned. We may have to add some type of storage, because when the thermostat satisfies on mild days the cycle timer that injects corn to keep the coals burning(2min. on / now 10 min. off) bumps the boiler temp up high enough (200+) to shut the timer curcuit off and the fire goes out.

So far it seems we've remidied that by changing the high limit to a SPDT high limit aquastat that when it hits the limit, energizes an isolation relay that shunts the room thermostat ie; temporary call for heat, to take the hot boiler temp down and keep it on line. Sort of a makshift dump zone if you will.

I'll try to find the disc w/the pictures.
Colin

Boilerpro_3

Steve, you should get about 70 gpm from one tekmar 361

with two NRF-22's. I'd look for some nice flat curve system lubricated pumps and check the amps draw to see what you could use.

Or you might want to try this setup. Use a variable speed set up along with an on off pump for injection. The variable speed pump takes care of low temp protection at warmer outdoor temps and ramps up to full speed once the return is at 140F. The on/off injection pump is controled by an aquastat on the return pipng set to come on when the boiler water is at 160F. Open attached pic. The injection pumps are the two grundfos pumps in the middle of the manifold.

In your case you might need 2 separate injection loops.... one piped to each half of a split main if you are controlling by an indoor sensor or on an outdoor reset curve. the one pump would vary in speed providing fine tuned control to the space, while the second could be cycled of an outdoor or indoor stat. Just some ideas.

BTW, for 120 Gpm . I believe a 3inch mix valve should work...depends on pressure drop and pump size. The engineers idea of varying the speed of the system pump has one major flaw. You could have delta tees of 100F form the beginning of the pipe run to the end, keeping the plants at the beginning of the piping way too warm and tose at the end too cold. Variable flow only seems to work well with emmitters like fan coils where temp drop through the coil is not an issue. Even here, I bet it could be a problem since at low flows water flow is laminar and once it turns turbulent, output jumps dramatically all at once, I'm told.

Just some thoughts.

Boilerpro

John R. Hall

Call me ignorant

But did we get off-topic and crosswire another subject -- or are we still talking about corn burning furnaces? Forgive me -- I am a lowly journalist.

Steve Ebels

You might be ignorant

But we still love ya John. If this project flies, I'll give you a call. I think it's going to be pretty neat and definitely off the beaten path.

John R. Hall

Thanks Steve

You know me too well, my friend. I'll keep an ear to the ground.

Colin

Photos......Finally found them

Burning corn in action at the worlds only original straw bale built museum in Carthage SD

Colin

Photos....Finally found um

burning corn in action at the worlds only original straw bale built museum in Carthage SD