Building several greenhouses and need boiler ideas

[drumwerx]

I am new to the forum and have been reading everything I can on the forum.

I am wanting to build one nursery greenhouse and one very large greenhouse and expand to more greenhouses slowly.

The nursery will have room for water storage and a wood boiler. I want to heat the floors in both greenhouses.

I am also hoping that I can use some solar panels to heat the storage water when the sun shines unless this is not a good idea and have the wood boiler to keep it heated at night and during the colder days in the winter. I am not sure what I can grow in the winter because I will wait and see how everything works first.

I am thinking that the nursery might have tripple wall polycarbonate and the larger greenhouse will have double layers of poly.

The Nursery will have about 1500 under glass and the larger greenhouses will have 3000 sq ft under glass.

How can I figure out my heating requirements with just the wood boiler for the greenhouses. What kinds of things do I need to look at to make this work?

Thanks everyone.

 

[peakbagger]

If you have access to a library, Home Power had an article about two years ago about a solar greenhouse installation for a native american tribe in the Green Bay wisconsin area. If your library doenst have the issue, the alternative is to buy their back issue CD. THe article was oreinted towards the solar end but it did comment about how the system was integrated into their other heating systems.

 

[Rick Stanley]

Drumwerx,

Here's a simple calc that may get you started: http://www.littlegreenhouse.com/heat-calc.shtml

Rick

 

[WoodNotOil]

I would think this would be a good application for a Garn. You could also go the route of an Eko or Econoburn etc. with storage if you plan to do some of the work yourself to bring down cost. Do the heat loss calc and call some of the dealers and get some info from them. As far as solar goes, I think you are going to get a lot of solar gain already through the "glass" of the greenhouses. The cost of the solar may out way the benefit in your situation, not sure though... good luck.

 

[drumwerx]

Here's a simple calc that may get you started: http://www.littlegreenhouse.com/heat-calc.shtml

I used the calc program but the greenhouse I am building will be different and not sure how to use this. I am building a 3 sided walled greenhouse with only the south wall glazed in a quarter circle. I used the calc to get something and came up with 750,00 to 1,000,000 BTU heater needed. Can these units heat that much?

I would think this would be a good application for a Garn. You could also go the route of an Eko or Econoburn etc. with storage if you plan to do some of the work yourself to bring down cost. Do the heat loss calc and call some of the dealers and get some info from them. As far as solar goes, I think you are going to get a lot of solar gain already through the "glass" of the greenhouses. The cost of the solar may out way the benefit in your situation, not sure though... good luck.

The solar gain I get I hope that I can harness it. I am hopping that I can store the straight sun gain into water barrels or the water stoarge system of the wood boiler. I also want to use solar trickle down mats that are $100 each instead of std. panels for hot water and store that into big storage tanks or the same storage tank the wood boiler would be using. So if I can get these 2 things to give me a lot of heat storage then maybe the wood boiler will not have to heat them that much. WIth the calculations I did above I think that I will need a very expensive wood boiler. Not sure what these can do though.

 

[Sting]

Heating appliance investment will be steep -- no mater

You may be better served with a series of residential gasifier boilers vs on huge engine to charge your (variable size) storage -- fail safe redundancy easier to handle + you can fire as to your needs so your always operating at peek efficiency!


I heated 6000 square feet of glass with double poly of the north roof faces with 750,000 input NG boiler and several NG fired fanned units.

 

[hoth2oguy]

I would recommend getting a professional to do a heat loss calc for you. As well you may want to consider a pellet boiler with fossil backup given how much heat you need to produce.

 

[pybyr]

Somewhere, I heard of what sounded like an ingenious idea of putting radiant heat in the surface of greenhouse benches- that way the living things, and the air immediately above them, stayed warm without the entire space having to be maintained at the same temperature. I don't know enough about horticulture to know if this is a truly feasible idea, but it sounded intriguing.

 

[hoth2oguy]

yup, run the radiant tubing right in the plant beds. Also heard of heating the water in a hydroponic set up and getting a lot of benefit from the heat emitted from the water into the greenhouse. The heat transfer / loss calcs for that kind of thing are way beyond me, however!

 

[Piker]

If you purchase a one million Btu Econoburn (EBW1000), your investment will be significantly less than if you purchase the same amount of output in several smaller boilers. I don't know about the other gasifier mfg's.

The boilers will output what their ratings are, but be aware that solid fuel appliances do not have static output. The ratings are arrived at under ideal circumstances, ie proper moisture content in the wood, proper installation, etc etc. In addition, if you push a gasifier to it's limit regarding it's maximum output, it's burn time will be short. This is not a problem when using thermal storage, but if you use thermal storage, you also have to have a boiler with enough output to satisfy the heat load AND charge the storage tank in the desired amount of time.

I really like the idea of running heat through the greenhouse benches. Sounds simple and very efficient.

cheers

 

[WoodNotOil]

I made this chart http://woodnotoil.googlepages.com/gassifiers a while back to compare some of the makes and models. There are more gasifiers available now, but it can give you an idea of what brands have large outputs. Give some of those companies a call and they can help you size.

 

[drumwerx]

Heating appliance investment will be steep -- no mater

You may be better served with a series of residential gasifier boilers vs on huge engine to charge your (variable size) storage -- fail safe redundancy easier to handle + you can fire as to your needs so your always operating at peek efficiency!


I heated 6000 square feet of glass with double poly of the north roof faces with 750,000 input NG boiler and several NG fired fanned units.

I like this idea with several smaller units. Like a pc with several hard drives in a raid configuration. With several, 2 or 3 units let say, go on at the same time. Or would it be possible to have one come on and when it burns and goes out another goes on and then the 3rd comes on. This way you just load the ones that were used. Is this what you are saying?

A 6000 sq ft greenhouse is huge. How did the NG work out? What kind of heat where you getting or average temperatures where you getting in the greenhouse? What are your average coldest temperatures at night?

What kind of water storage did you have for the NG? I do not know what kind of average water temperatures these things get. Also not sure what kind of temperature you need to use them for radiant heating for the root zone.

Do you think it is possible to use the heat gain from the sun to help warm the water storage tank or tanks? Or do I just have to put the water storage tanks in a well insulated room so I do not have that much heat loss during the cold nights. The reason I say this is there must be a way to warm the water from the sun in barells and send the warm water to the storage system during the day. Or is it that we just will not get the same kind of heat that you do from the sun like you do from the wood boilers. If these tanks are exposed in the greenhouse that have been warmed would they give off heat to the plants or would I just be loosing to much heat and defeating the radiant heat I will be using at night anyway. Also I read about a different solar panel called a trickle down mat that was about $100 per panel instead of the normal $700 to $1000. You just have to make these yourself.

 

[drumwerx]

I would recommend getting a professional to do a heat loss calc for you. As well you may want to consider a pellet boiler with fossil backup given how much heat you need to produce.

I like the idea of having the propane backup but would rather use wood for the boiler. That way I can get the wood for free and not be forced to keep paying higher and higher pellet prices.

 

[drumwerx]

If you purchase a one million Btu Econoburn (EBW1000), your investment will be significantly less than if you purchase the same amount of output in several smaller boilers. I don't know about the other gasifier mfg's.

The boilers will output what their ratings are, but be aware that solid fuel appliances do not have static output. The ratings are arrived at under ideal circumstances, ie proper moisture content in the wood, proper installation, etc etc. In addition, if you push a gasifier to it's limit regarding it's maximum output, it's burn time will be short. This is not a problem when using thermal storage, but if you use thermal storage, you also have to have a boiler with enough output to satisfy the heat load AND charge the storage tank in the desired amount of time.

I really like the idea of running heat through the greenhouse benches. Sounds simple and very efficient.

cheers

I understand the investment will be less and will look at both ways 2 smaller units versus the one large unit. I also see what you are saying about the storage. You have to make sure that the unit works well with the correct size water storage system. I posted some other ideas just above on helping the water storage set up with solar sun help and solar water trickle down mats and I am hoping I get more feedback from these ideas.

 

[drumwerx]

I made this chart http://woodnotoil.googlepages.com/gassifiers a while back to compare some of the makes and models. There are more gasifiers available now, but it can give you an idea of what brands have large outputs. Give some of those companies a call and they can help you size.

Thanks for the charts I will start calling some of these companies on Monday.

http://www.solarbubblebuild.com/build_images13.php
this rules!http://www.tdc.ca/bubblegreenhouse.htm

I checked into this and emailed the original inventor on this and they never had a real good way to keep the bubbles from freezing and automatically adding bubbles correctly. They were hopping that a large school or company would take it on and get a grant to work out some of the bugs in the idea. I do not think they have that all worked out yet.

Also Pike how do you like your

 

[pybyr]

I can see the point of having two for something like a greenhouse where you risk losing a crop- by having a certain amount of redundancy if one fails- but cost- wise, and complexity-of-plumbing and control-wise, I think you'd get into _severe_ diminishing returns with any more than two.

In fact, from anything I'm aware of, these are sufficiently robust and reliable devices that I think that unless you have an unusual absence of cost constraints, then Piker's point is a good one- get one very big unit- and then keep some spares on hand for critical items like blowers and controllers.

Also, for what it is worth, even though the typical modern greenhouse is a "hoop house" that goes from the ground up, years ago, I was in a greenhouse where the footings were about 4 feet below ground level, and then the transparent part of the structure simply went up from that "knee wall"-- always seemed like a good idea to me, in that the net % of "outdoor surface" was reduced by the fact that a significant part of the volume was below ground. If your local geology and water table permit, perhaps you might want to do something like that, with ICF (insulated concrete form) sidewalls. Heck, while you're thinking along those lines, if you have a big site, what about a geothermal heat pump for moderate weather, and just use the wood for the serious cold?

 

[Sting]

http://forum.iburncorn.com/viewtopic.php?t=10263

Can you travel?

 

[WoodNotOil]

Heck, while you're thinking along those lines, if you have a big site, what about a geothermal heat pump for moderate weather, and just use the wood for the serious cold?

Not to start an argument, but I have heard geothermal is very expensive to install and you can pay a lot for the electricity while it is running. I would think it would be either wood or geothermal, not both. Too costly.

 

[jdboy9]

One of our local greenhouses has about 3 acres under glass. They use a Hurst (i think it what its called) biomass boiler. It burns all the waste from their dairy farm and heats all their needs. It is all computer controlled and the boiler itself is as big as a small two story house Maybe not what you are looking for but just I would throw that in.

 

[drumwerx]

I can see the point of having two for something like a greenhouse where you risk losing a crop- by having a certain amount of redundancy if one fails- but cost- wise, and complexity-of-plumbing and control-wise, I think you'd get into _severe_ diminishing returns with any more than two.

In fact, from anything I'm aware of, these are sufficiently robust and reliable devices that I think that unless you have an unusual absence of cost constraints, then Piker's point is a good one- get one very big unit- and then keep some spares on hand for critical items like blowers and controllers.

Also, for what it is worth, even though the typical modern greenhouse is a "hoop house" that goes from the ground up, years ago, I was in a greenhouse where the footings were about 4 feet below ground level, and then the transparent part of the structure simply went up from that "knee wall"-- always seemed like a good idea to me, in that the net % of "outdoor surface" was reduced by the fact that a significant part of the volume was below ground. If your local geology and water table permit, perhaps you might want to do something like that, with ICF (insulated concrete form) sidewalls. Heck, while you're thinking along those lines, if you have a big site, what about a geothermal heat pump for moderate weather, and just use the wood for the serious cold?

I will look into a larger one and think more on these lines.

As far as the greenhouse goes I am doing a North, West and East wall in Pumice to an R factor of 30. The south wall will have a 3' pony wall then the glazing begins going to the roof. So I will only have the south wall exposed and will be better off than a complete hoop house. The pumice will be in the ground and the radiant pex pipes on top of it so I will have great insulation to the earth.

Typically what kind of water temperature do you get from these boilers?

 

[Piker]

I made this chart http://woodnotoil.googlepages.com/gassifiers a while back to compare some of the makes and models. There are more gasifiers available now, but it can give you an idea of what brands have large outputs. Give some of those companies a call and they can help you size.

Thanks for the charts I will start calling some of these companies on Monday.

http://www.solarbubblebuild.com/build_images13.php
this rules!http://www.tdc.ca/bubblegreenhouse.htm

I checked into this and emailed the original inventor on this and they never had a real good way to keep the bubbles from freezing and automatically adding bubbles correctly. They were hopping that a large school or company would take it on and get a grant to work out some of the bugs in the idea. I do not think they have that all worked out yet.

Also Pike how do you like your

I don't have any experience installing any thermal solar, but from what I have been told, it is absolutely fantastic. It's relatively inexpensive, easily integrated with a boiler setup, and can produce quite a bit of output... providing the sun actually shines, which never seems to happen here in NW PA... thus thermal solar in my neck of the woods doesn't get used that much. If you look at some of the "cloudiest cities" lists on the net, western PA has quite a few right near the top.

I like the idea of having multiple boilers for the redundancy issue. One big boiler shuts down for some reason without a backup, and you stand to lose alot of money in product on a bitter cold night. One of two or 3 smaller boilers shut down, you might have problems keeping the temp up where you want it, but you will likely be able to at least keep your product from freezing until you get all of the units back up and running. This diversity of control will definitely cost you. If you are going to have a propane backup of some sort, my opinion is still to go with one wood boiler to meet demand.

On a side note: Econoburn will custom build a 1,000,000 Btu boiler for you with just about any size door. I recently had an EBW1000 priced out for a customer who wanted a 4' wide door by 3' tall so they could load wood via pallets with a fork truck into the firebox. Just something to think about.

As far as how I like my Econoburn... well, I love it. As a dealer and a user, I couldn't be happier with the quality and simplicity of the product. Makes my life a lot easier from both a professional and domestic perspective. You are more than outside my sales region... but you are also more than welcome to pick my brain if you have any specific questions about the product, or need contact information.

cheers.

 

[Piker]

Water temps are simliar to any other boiler... no lower than 150 (controls prevent heat draw on the boiler when water lower than 150... reduces condensation in the heat exchanger) and as high as probably 200. You start going over 200, especially with the bigger boilers, and you are getting pretty close to the overheat setting.

cheers

 

[Sting]

You can make steam if you want -- but (IMO) that's not what you want = That's SOP greenhouse technology prior to the 60's -- yet steam out in the range is great because you can quickly sterilize soil batches right in bench

I would make a thermal mix (bypass) loop so your sending low temp water - mild energy out into the load radiation and keep only the plants and soil warm -- that will warm the air in the room days with solar gain -- at dusk, pull thermal blankets just over the crop to limit the radiation space and the crop will stay warm till dawn when the blankets are slowly withdrawn so as not to shock the crop whit the cold air from above.

But this is all old stuff we did back in the 70's to remain competitive -- I don't want to even think of operating at today's energy cost and (Walmart driven) consumer market

 

[drumwerx]

I don't have any experience installing any thermal solar, but from what I have been told, it is absolutely fantastic. It's relatively inexpensive, easily integrated with a boiler setup, and can produce quite a bit of output... providing the sun actually shines, which never seems to happen here in NW PA... thus thermal solar in my neck of the woods doesn't get used that much. If you look at some of the "cloudiest cities" lists on the net, western PA has quite a few right near the top.

I like the idea of having multiple boilers for the redundancy issue. One big boiler shuts down for some reason without a backup, and you stand to lose alot of money in product on a bitter cold night. One of two or 3 smaller boilers shut down, you might have problems keeping the temp up where you want it, but you will likely be able to at least keep your product from freezing until you get all of the units back up and running. This diversity of control will definitely cost you. If you are going to have a propane backup of some sort, my opinion is still to go with one wood boiler to meet demand.

On a side note: Econoburn will custom build a 1,000,000 Btu boiler for you with just about any size door. I recently had an EBW1000 priced out for a customer who wanted a 4' wide door by 3' tall so they could load wood via pallets with a fork truck into the firebox. Just something to think about.

As far as how I like my Econoburn... well, I love it. As a dealer and a user, I couldn't be happier with the quality and simplicity of the product. Makes my life a lot easier from both a professional and domestic perspective. You are more than outside my sales region... but you are also more than welcome to pick my brain if you have any specific questions about the product, or need contact information.

cheers.

When you say thermal solar is that called geothermal? Where I live I get about 300 days or more of sun a year.

In asking about the temperature of the water I guess I need to know what temperature do you need to have in a boiler to make radiant heat go to 35 degrees so nothing freezes or 65 so I can grow tomatoes. Then I know the low and the high in a 3000 sq ft area. How can I calculate this?

 

[Piker]

My kingdom for 300 days of sunshine per year. Back when I was just a pup, there was a list going around that had Meadville PA as the second cloudiest place in the united states next to seattle washington. It is rediculously cloudy here...

Geothermal and thermal solar are two different animals. Geothermal extracts heat from the earth's crust which maintaints a constant temperature of about 55 degrees. By using hundreds of feet of buried pipe, a few pumps, heat exchangers, and compressors, you heat your home off of the energy stored in the dirt... and a fair amount of electricity. Usually a large investment up front.

Thermal solar is basically just using the suns energy to heat water inside of a thermal solar panel, and then circulating that water to wherever you need it. The thermal solar panels are basically just tubes of water inside a box with a glass face on them. That might be oversimplified, but you get the jist. Like I said, it's relatively inexpensive, especially compared to photovoltaic solar, and it's a good supplement that is relatively easy to encorporate with a wood fired boiler system.

I guess I don't know 100% what you are asking with regard to the water temp. And to be up front with you, I don't know all the mechanics of a greenhouse and what you guys need as far as heating goes. I suppose if you put hot water heat in the benches below your plants, you wouldn't want to have 180 water going through them or you would cook your tomatoes before you get a chance to sell them. Basically, whatever temperature you need the water, you will just temper it or mix it... meaning the supply to whatever zone you are feeding will automatically draw some of the return water from that zone before it goes back to the boiler and mix it with supply from the boiler to keep the water temp down where you want it. My guess is, along with heat in the benches, you would probably want some air handlers as well. You could use the fans on the air handlers to keep the air moving inside when the weather warms up.

Am I the only person not watching the Super Bowl?

cheers