Sizing a wood boiler for two hoop houses

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SRNursery

New Member
Jul 20, 2021
4
Virginia
I'm looking to purchase a wood boiler to heat two hoop houses that are currently under the construction. The hoop houses are located in USDA zone 7a of Virginia and are each 20x50 feet, roughly 12ft at the peak, wrapped in 6mil poly film with 8mm twin wall polycarbonate front and back faces. We hope to keep the hoop houses around roughly 60-65 F during the coldest months around here for hemp plants. The average temp during cold months around here is about 35-40 F. We expect poor insulation due to the 6mil film covering both hoop houses.

Wood supply is no issue as we work with a tree company who hauls all different types of logs back daily and we also have capabilities to cut and split the wood.

The budget is around $7,000. If anyone could point me in the right direction that would be great.

Thanks
 

stoveliker

Minister of Fire
Nov 17, 2019
907
Eastern Long Island NY
How are you going to be sure you are burning dry wood when burning that much? Are you going to be able to store 2 years worth of split, stacked and preferably covered wood? Wet wood wastes a lot of energy in evaporating the water in it, creates a lot of pollution, and creosote (fire hazard).
 
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E Yoder

Minister of Fire
Jan 27, 2017
549
Floyd, VA
Is this going to be inflated double poly? That would help some, but greenhouses are a big BTU load.
$7,000 is pretty low to get a wood boiler installed.
 

SRNursery

New Member
Jul 20, 2021
4
Virginia
Is this going to be inflated double poly? That would help some, but greenhouses are a big BTU load.
$7,000 is pretty low to get a wood boiler installed.
The plan is to have a single poly film with another film of panda plastic covering for light dep. We may explore double poly with a blower if it reduces the BTU requirement drastically.

The $7,000 is for the unit only, we have a guy who will install the pipes and heat exchangers that we are budgeting for separately.
 

Bad LP

Minister of Fire
Nov 28, 2014
1,588
Northern Maine
Is this going to be inflated double poly? That would help some, but greenhouses are a big BTU load.
$7,000 is pretty low to get a wood boiler installed.
Will 7 K even buy a boiler??
 

E Yoder

Minister of Fire
Jan 27, 2017
549
Floyd, VA
7k might buy a pretty basic model but barely, the EPA restrictions wouldn't apply to a greenhouse hookup so a cheaper conventional updraft model could be used.
An EPA approved gasification model will be over $10k to heat that large of greenhouse space. Maybe more like $12k.
 

salecker

Minister of Fire
Aug 22, 2010
1,433
Northern Canada
Read everything on this site you can for the next few weeks.
Budget is small,good shopping could get you a good used gasifyer if you are patient
Get cutting and splitting now so you can use the free wood next year or maybe even the year after,depending on what wood you get for free.
Line up this years wood befor the demand of cold weather shows up and everyone is looking for dry wood.
 

SRNursery

New Member
Jul 20, 2021
4
Virginia
7k might buy a pretty basic model but barely, the EPA restrictions wouldn't apply to a greenhouse hookup so a cheaper conventional updraft model could be used.
An EPA approved gasification model will be over $10k to heat that large of greenhouse space. Maybe more like $12k.
It looks like I ran the budget wrong in my initial post, we are willing to spend over $10k on a unit. Just looking for sizing advice
 

SRNursery

New Member
Jul 20, 2021
4
Virginia
Addressing the comments about wood- our parent company hauls several dump trucks of oak, ash, hickory, etc daily from tree service. Wood will not be a limiting factor with the unit
 

stoveliker

Minister of Fire
Nov 17, 2019
907
Eastern Long Island NY
Addressing the comments about wood- our parent company hauls several dump trucks of oak, ash, hickory, etc daily from tree service. Wood will not be a limiting factor with the unit
The question is not wood. The question is DRY wood. Oak needs two years or more to dry. Otherwise you'll have a dripping creosote fire hazard on your hands.
 

maple1

Minister of Fire
Sep 15, 2011
10,777
Nova Scotia
Addressing the comments about wood- our parent company hauls several dump trucks of oak, ash, hickory, etc daily from tree service. Wood will not be a limiting factor with the unit
It also has to be processed.

How much are you thinking you might use? I'm not familiar with hoop houses but that sounds like a huge load. I would suspect 20 cords at bare minimum. Of dry stuff. Straight off the truck would be a lot more. An inefficient boiler more again.
 

salecker

Minister of Fire
Aug 22, 2010
1,433
Northern Canada
Addressing the comments about wood- our parent company hauls several dump trucks of oak, ash, hickory, etc daily from tree service. Wood will not be a limiting factor with the unit
Yes you mentioned that ...
DRY WOOD is what you need,that is going to be your biggest problem for a couple of years till the green stuff is dry after you split and stack it