Greenhouse Physics Type Brain Twister.

[NotCranky]

I think there are a few people here would could get interested in a hoop house or greenhouse design question and have the knowledge to come up with good/efficient (math supported)ideas.

I have three black and dark green 5,000 gallon water tanks on a hill aligned in a row with a south solar aspect. In the afternoon a few days ago the water was 71F. On a typical January morning the outside temp was 41F and the water was 62F. Our coldest average nights are 44 with about 10 light to moderate frost days per year.

Unless I am totally out to lunch it looks like these tanks release 1,200,000 BTU’s dropping from 70F-60F and would do the same going from 60F-50F. So 2,200,000? I was hoping to design around that potential(unless I am out to lunch) and maybe more Solar heated stuff if necessary…like the possibility of an electric heated above ground fish tank(small swimming pool) in the greenhouse. Maybe added heat to the fish water would take the thing through the frost nights. Also I guess with almost all crops a few nights well under 50F(but not freezing) would not matter as long as most nights were warmer, which they would be. Basically looking at getting 10-20 degrees differential, through the night in the two or three coldest months. Probably use air circulation fans and an R value of 1 for the glazing(though the north sides could be insulated)

So what is the cold season potential here? How big can the house be w/o added energy? Tent them with plastic and build a monster? Also thinking about building a lean-to type structure against the south side but that would not be very large . Then I would insulate the exposed north side of the tanks. Water would probably get much hotter in the day time to give off more Btu’s at night.

Rustico,
Gentleman Farmer.

[NotCranky]

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[NotCranky]

Tanks, entry should say 15000 gallons.
http://www.bigpumpkins.com/Diary/DiaryView.asp?season=2011&grower=51490&action=L

[NotCranky]

Tanks, entry should say 15000 gallons.
http://www.bigpumpkins.com/Diary/DiaryView.asp?season=2011&grower=51490&action=L

[NotCranky]

Tanks, entry should say 15000 gallons.
http://www.bigpumpkins.com/Diary/DiaryView.asp?season=2011&grower=51490&action=L

[NotCranky]

Tanks, entry should say 15000 gallons.
http://www.bigpumpkins.com/Diary/DiaryView.asp?season=2011&grower=51490&action=L

[NotCranky]

Tanks, entry should say 15000 gallons.
http://www.bigpumpkins.com/Diary/DiaryView.asp?season=2011&grower=51490&action=L

[patb]

rustico

the question is how efficient the house is at insulation.

the other is your design limit.

The Average cold weather is 49F

9 days have broken 32F in 140 years.

The coldest day recorded was 25F.

i would suggest designing to 33F, and if you get an extreme cold weather event get some space heaters.

and set 4241 degree days for heating.

http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

here’s a good calculator, set your Insulation and details, and calculate your losses to match the BTU’s in your tank

[patb]

rustico

the question is how efficient the house is at insulation.

the other is your design limit.

The Average cold weather is 49F

9 days have broken 32F in 140 years.

The coldest day recorded was 25F.

i would suggest designing to 33F, and if you get an extreme cold weather event get some space heaters.

and set 4241 degree days for heating.

http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

here’s a good calculator, set your Insulation and details, and calculate your losses to match the BTU’s in your tank

[patb]

rustico

the question is how efficient the house is at insulation.

the other is your design limit.

The Average cold weather is 49F

9 days have broken 32F in 140 years.

The coldest day recorded was 25F.

i would suggest designing to 33F, and if you get an extreme cold weather event get some space heaters.

and set 4241 degree days for heating.

http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

here’s a good calculator, set your Insulation and details, and calculate your losses to match the BTU’s in your tank

[patb]

rustico

the question is how efficient the house is at insulation.

the other is your design limit.

The Average cold weather is 49F

9 days have broken 32F in 140 years.

The coldest day recorded was 25F.

i would suggest designing to 33F, and if you get an extreme cold weather event get some space heaters.

and set 4241 degree days for heating.

http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

here’s a good calculator, set your Insulation and details, and calculate your losses to match the BTU’s in your tank

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