large boiler for my dad

[flyingcow]

brian, if you go with a Garn you really need seasoned wood. seasoned at least a year IMO. You've stated that getting a yrs wood ahead is not in the plan. Maybe the plan has changed.

FWIW- I have a dairy farmer that burns between 50 to 60 cord a year. He's as stubborn as they come. He has a Royal OWB.

 

[brian89gp]

Maybe the plan has changed

I might be able to convince him to change the plan if the benefits of a gassifier such as the Garn are appealing enough, such as sleep or being able to venture away from the wood pile for more then a few hours to actually do some work.

Similar results could be had from an OWB as well, just by different means. Instead of saving time by reducing the amount of wood he would save time by the amount of processing required for said wood.

Just gathering good options to present. That Royal 6490 looks like a possibility. Which model does your dairy farmer have and how long does he get on a burn between reloads?

 

[flyingcow]

I'm not sure which one he has. It's a pressurized unit. Doesn't look any better than any other OWB. Not sure how long between loads. Not very long.

 

[goosegunner]

I would do some more searching, Heaterman posted about his findings with a very large central boiler that performed very poorly for heat output vs consumption at a dairy farm. It would be similar in that the load was very large. It burned at a high rate but btu transfer was really bad.

There is also another user here with a royal outdoor that has expressed very high wood consumption even with dry wood for his residential setting.

gg

 

[bigburner]

The Farm 2000, this Idea should catch better, not sure why it hasn't. This has a large combustion chamber and will do a form of updraft gassification during the middle of the burn cycle, it's not needed at the end. These units allow for large logs, higher moisture and little or no creosote. I didn't know they were sold in the US. I used some ideas from them when setting up my unit. I have never seen one in person but I know that mine will [from a layer of coals in the bottom] turn 2 or 3 big wheel barrows full of wood in to a glowing mass in an hours or so. [then fan shuts off] I have rail road tracks in the back to protect the back wall, these will become red hot in an hour +/-. My point is - updraft gasification is real and it works. the negative is, it looses on start up [delay] . the positive is load and walk away. Get Dad this one.

 

[flyingcow]

brian, I wasn't endorsing the Royal unit. It's a typical OWB. My vote is for the Garn.

But with your btu needs, can you make use of storage? can you batch burn a big enough btu output to charge a large battery of water to go for another 12 hours just on storage?

 

[wrightk20]

The garn sure would be an easy plug and play deal. An owb sized for the load you have would end up using more wood than you already are. Possibly close to double the amount. I would think radiant heat in those greenhouses would be a good setup to look into. Either with insulating the floor and putting tubing down or possibly using some cast iron radiators so that you could use your stored water down to 100*F or less. The hanging modine heaters don't seem to work to well with water temp less than 130-140. The Garn would be an easy choice for me in your situation. Kevin

 

[brian89gp]

Heaterman posted about his findings with a very large central boiler that performed very poorly for heat output vs consumption at a dairy farm

I have been talking with him separately and he has mentioned this.

The Farm 2000, this Idea should catch better, not sure why it hasn't

my choice for an upgrade is a FARM 2000

I'll do some research into this

brian, I wasn't endorsing the Royal unit. It's a typical OWB. My vote is for the Garn

I know you weren't. I just hadn't been able to find a large unit on my own research, nothing else. The pricing is close between the large Royal and a Garn anyways.

The garn sure would be an easy plug and play deal. An owb sized for the load you have would end up using more wood than you already are

A Garn or a pellet boiler are my first choice too. Even though I don't have a unit, I am a die hard believer in a gassification boiler and it was in fact why I signed up 5 years ago to this site. Me personally, I would never own a OWB, but I am doing research for someone else and have to take their habits that may be hard to break into consideration. My girlfriend brought up a good point last night too, the OWB can take huge pieces of wood and burn them somewhat unseasoned but over the comming years the size of pieces my dad can handle will get smaller and smaller until they are the seasoned split size so why not just skip the middle and go with seasoned splits and get a Garn.

 

[brian89gp]

But with your btu needs, can you make use of storage? can you batch burn a big enough btu output to charge a large battery of water to go for another 12 hours just on storage?

Yes. The storage setup is complicated by the fact that there is only a heating need during the night. If it is reasonably sunny during the day there is enough solar heat gain to keep the greenhouse warm even if it is -10 outside. Also add to the fact that anything that can corrode will corrode on very short order if put inside the greenhouse due to the constant 80%+ humidity and the fertilizers in the water (types of salt typically...).

Most definitely if the storage is insulated as then any extra heat from overnight can be saved (less losses) for the next night. The Garn is nice in that it has a decent amount of storage built in. The downside is that it requires working pumps, fan coils, and piping systems to deliver the heat on demand and should you go to sleep with the trust that they will work through the night and they don't you just lost a lot of product in the matter of a couple hours and until the next year you have no hope of recovering. Plant sales are seasonal, you miss the target date for delivery (by needing to start over) and you don't have a market to sell it to so you got to wait until the next year. Double or triple redundancy would be required as well as backup power of some sort.

If going with a storage inside the greenhouse to heat via radiation off of the tank, as long as corrosion on the outside surface and proper sizing is done then it should work. Having the tank at 140* into the daylight hours just wastes the heat and the wood required to produce it. I would love to go this route because it means short of your tank bursting as long as the tank is up to temp you can be assured that the greenhouse will be warm for the next XX hours. No pumps to fail, no fans to fail, no worry of electrical loss, etc. Just have to figure out the the right right water temps for the overnight lows so that the heat isn't wasted heating the greenhouse during the sunlight hours.

 

[wrightk20]

The amount of electric load that it would take to run a Garn, pumps, and fans would be minimal. A small generator could easily supply power to the system to keep everything working. Sounds like you would need maybe some sort of system to alert you when temps in each greenhouse got down to a certain temp. Then it would give you time to either start a generator or change a failed pump or fan to get things back into operation. I just don't think that one big tank in each green house uninsulated would give you a controlled temperature that you would be looking for. Kevin

 

[brian89gp]

I was leaning on the side of fan coils and a generator too, easier to control and deliver the right amount of heat and not waste wood. 4A per fan coil (pump and fan), 2 fan coils per greenhouse, and 3 greenhouses. 3000W for the pumps and fans then whatever for the boiler, enough for a standard 4500/5000W generator to run so you are right.

Gotta run the cost of using long fin tubes vs the fan coil, I would imagine that a couple 100' runs of fin tube would be enough heat but need to run the calculations first. Would reduce the number of moving parts and electrical load which is never a bad thing.

 

[wrightk20]

I agree that some sort of radiant heat would be best. You would be able to use more of your stored heat if sized correctly. Kevin

 

[flyingcow]

You got alot to figure out Brian. Interesting, especially when you throw in the fact of one bad night ruins the season. The old barrel stoves don't break down.

 

[brian89gp]

Using 3-400 linear foot of fin tube to provide pump redundancy should also give the required BTU down to water temps at or below 140*, gives a storage system a lot of room to flex its muscles. Two pumps per greenhouse each driving half of the fin tube for redundancy. Something tells me that amount of fin tube is not as cheap as a fan coil and fan though.

How would I go about controlling a system like this? Constant on pump with a mixing valve? Any electronics need to either be water and humidity proof or outside of the greenhouse. The system would probably have antifreeze in it.

The old barrel stoves don't break down

Indeed they don't. And as a bonus they eat so much wood that you get to double check on them at least once every 2 hours

 

[brian89gp]

Well, it looks as if my mom is gonna talk some sense into him about downsizing and having a realistic amount of work to keep up with, one greenhouse most likely, two tops. Pellet is unlikely due to the ongoing yearly fuel cost where as wood is free. Due to downsizing the demand I would be able to catch up and get several years ahead on the firewood collecting and seasoning. Boiler is still preferred over forced air due to the heat storage capabilities of water. So it looks like 130k most likely with a possibility of 260k.

 

[heaterman]

I was leaning on the side of fan coils and a generator too, easier to control and deliver the right amount of heat and not waste wood. 4A per fan coil (pump and fan), 2 fan coils per greenhouse, and 3 greenhouses. 3000W for the pumps and fans then whatever for the boiler, enough for a standard 4500/5000W generator to run so you are right.

Gotta run the cost of using long fin tubes vs the fan coil, I would imagine that a couple 100' runs of fin tube would be enough heat but need to run the calculations first. Would reduce the number of moving parts and electrical load which is never a bad thing.

I think you'd probably be better off with the fan coils than baseboard in your application. 100' of baseboard @ 180 is going to average about 50-60,000btu's output. 200 feet would not pump out what you need plus BB would really restrict your operating temperature range.