Win a copy of The Tourist Trail this week in the Writing forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education experiences global resources the cider press projects digital market permies.com private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • r ranson
  • Anne Miller
  • paul wheaton
stewards:
  • Joseph Lofthouse
  • Jocelyn Campbell
  • Mike Jay
garden masters:
  • Steve Thorn
  • Dave Burton
  • Joylynn Hardesty
gardeners:
  • Carla Burke
  • Pearl Sutton
  • Greg Martin

passive solar greenhouse ventilation

 
Posts: 3
Location: NW Arkansas
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I am new here so sorry in advace if I posted this wrong.  I am building a passive solar greenhosue with a earth battery.  I am looking a ventalion system that wont lost heat when not in use.  What are you guys using?  
 
steward
Posts: 4827
Location: Northern WI (zone 4)
1306
hunting trees books food preservation solar woodworking
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Douglas, welcome to Permies!  I'm using a series of vents along the ridge and along base of the south wall on my greenhouse.  Some of them open with automatic openers, others I just prop open.  When they're closed, their weight keeps them shut and weatherstripping keeps them somewhat sealed.
 
gardener & author
Posts: 1659
Location: Ladakh, Indian Himalayas at 10,500 feet, zone 5
258
trees food preservation solar greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
My greenhouse is attached to my earthen house, so it's also like an earth battery I guess.

I live in the high desert, with very cold winters but sunny most of the year, so in the summer it would overheat terribly if left to its own devices. I have a window at one end and a door at the other, as well as windows and doors on the north side into the house. So when I want the heat in the house, I open the doors into the house. In the shoulder seasons, ie fall and spring, I open the door and window at both ends for ventilation during the day whenever it seems likely to get too hot. In early fall and late spring, I leave those open day and night. For summer we take the plastic glazing right off, fold it up and store it away.  Last year we put the plastic up on 15th October and removed it in mid-April. Mid-Oct worked perfectly (tomatoes and other things didn't freeze in the greenhouse space before that even though they were open to the sky till then), but mid-April was too early, and my warm weather seeds didn't germinate until June. Every year the weather is slightly different.

Eliot Coleman says that a ratio of about 1:7 end:length ratio is good for ventilation, if you can remove the ends of a greenhouse for the summer. In my climate I think that might still get too hot in summer and cook the plants.

This window is not large enough to ventilate well, and at first I couldn't close it because the cat needed it as a door. Later I made a different cat door down at ground level and nailed plywood over the window.
attached-greenhouse-november-with-window-as-cat-door.jpg
[Thumbnail for attached-greenhouse-november-with-window-as-cat-door.jpg]
This window is not large enough to ventilate well, and I couldn't close it because the cat needed it as a door.
2018Oct-stone-raised-bed-before-greenhouse-was-covered-for-winter.jpg
[Thumbnail for 2018Oct-stone-raised-bed-before-greenhouse-was-covered-for-winter.jpg]
October before the plastic was installed
 
gardener & bricolagier
Posts: 2789
Location: SW Missouri
872
goat cat fungi books chicken earthworks food preservation cooking building homestead ungarbage
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Automatic vent openers they do not have to be electric. This type opens due to expansion when heated. The word I was looking up for you was "bimetal greenhouse vent openers" there are a lot of them around. Bimetal Vent opener at Lowes.

These are what people mean here when they say "automatic openers" not some electrical device on a timer system.

:D
 
Douglas Cole
Posts: 3
Location: NW Arkansas
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks for the info.  I got an openner that opens at 70 to 90 degrees.  If I put vent on south wall at the bottom what temp should it be to open.
 
Mike Jay
steward
Posts: 4827
Location: Northern WI (zone 4)
1306
hunting trees books food preservation solar woodworking
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Can you put the opener on the upper vent?  Mine opens around 90 degrees (up at the ceiling) so the greenhouse down at floor level stays in the 80s.  The lower vents stay open so air only moves through the greenhouse when the upper vents open up.
 
This parrot is no more. It has ceased to be. Now it's a tiny ad:
One million tiny ads for $25
https://permies.com/t/94684/million-tiny-ads
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!