January Update Enclosing the Greenhouse

Its been a busy fall, what with creation of the Aquaponics Association (yours truly is Secretary of the US Chapter). But I finally got a chance during the holiday break to enclose my greenhouse. Not much growing going on, but the fish are all doing fine, even through the nasty cold snap that swept through the eastern United States in early January.

I shot a bit of video on January 1st, when it was cool (55 degrees) but sunny. With the greenhouse enclosed, it got up to 83 degrees inside. Nuts! Slipping into the greenhouse was a bit like getting off the plane in a tropical locale.

For the roof of the greenhouse I simply have a double thickness of 3.5 mil plastic - though I dont have this inflated, there is still insulation value from the small air pockets between the two sheets. This is a time when "rumpled" helps.

Ive been wanting to install some method of measuring temperatures, but the Stout family has collectively decided to be fiscally responsible in 2012. So no impulse purchases of environmental monitoring equipment for Meg. Ive gotten a kickstarter project approved which would let me ask the collective crowd to contribute to the monitoring experiment (for prizes!). Ill see about going live on that project in the next week or so.

Anyway, heres video of the state of things on January 1st, starting with a snippet of video from September to explain how I get 10 foot wide sheeting to cover a greenhouse.

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Keeping things warm

I hate working outside in the cold.

Unfortunately, I didnt get my two heating solutions finished before cold set in. With work, family, and short days, Ive not had the time Id hoped to finish things off.

Another concern Ive had is getting things too warm. Since my greenhouse is so tiny, I had visions of scalding water and melted plastic. So I wanted to measure temperatures with the rocket mass heater without it being connected to the greenhouse.

This past week I finally got the rust stripped off and painted the drum and lid (from a second-hand 22.5" Weber grill) with high temperature paint. The high temperature paint is supposed to be able to go to 800 degrees Fahrenheit without out-gassing or burning off.

Ive got a video here showing how I assembled the innards. I want to be able to disassemble the rocket mass heater, so making the components of cob isnt my first choice. If I had a chance to do this over, I would cut two 8 inch holes into the base plate or "lid" of the barrel.



Ive found that its a bit tricky getting these heaters to start. The method that ended up working for me is to start off with crumpled newspaper and a wax & eggcarton fire starter. Then feeding in small diameter sticks with the occasional piece of junk mail works great.

In my initial burn, I found that the top of the barrel (inside the domed lid) got to about 400 degrees Fahrenheit. The sides of the barrel warmed my hands when held about an inch away, and the top of the domed lid provided a similar level of diffuse heat.

If I had a greenhouse that was taller and could make a second version of this, I would consider having the heater inside the greenhouse. My greenhouse is short, however, so the roof plastic would only be a few inches above the domed lid. And this first version has the big rough rectangular hole for the exhaust, so I would be concerned about the exhaust fumes leaking in the enclosed space.

My next step will be constructing a nicer base out of bricks and connecting the exhaust to the duct work and structure inside my greenhouse.

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