• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies living kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education experiences global resources the cider press projects digital market permies.com all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • raven ranson
  • Jocelyn Campbell
  • Julia Winter
stewards:
  • paul wheaton
  • Burra Maluca
  • Devaka Cooray
garden masters:
  • Anne Miller
  • Pearl Sutton
  • Joylynn Hardesty
  • Shawn Klassen-Koop
gardeners:
  • Joseph Lofthouse
  • Bill Crim
  • Mike Jay

With a whole ton of thermal Mass, could I get away with no venting?  RSS feed

 
pollinator
Posts: 1527
Location: Denver, CO
44
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have a high tunnel, and don't want to go to the expense of installing an automatic vent opener. Could I just add so much thermal mass that all the extra heat is absorbed? Or would this not be physically practical?
 
author
gardener
Posts: 946
Location: 6200' westen slope of colorado, zone 6
65
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I think not possible. In my Colorado greenhouse, heat buildup in the summer is the biggest extreme of climate. Without ample venating (emphasis on ample), your plants will be severely heat stressed, if not cooked outright. I would say that planning the ventilation is a more important consideration than the heat retention. I would suggest two vents, to allow cross-ventilation. You will not regret having too much ventilation.

A greenhouse cools down slowly, but it heats up really fast. Plants do not like sudden temp changes, hot or cold. When your greenhouse is 65 degrees in the morning, and then heats up to 120 by 10am in the direct sun, your plants will suffer profoundly.

Thermal mass is simply not going to be able to absorb that kind of temperature change rapidly enough to matter. Even with a sophisticated 'climate battery', like Jerome uses at CRMPI, I think you are going to need vents for the sunniest days of the year. His greenhouses all certainly have external vents in addition to climate batteries.
 
Posts: 59
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Adam is absolutely correct.
Either manually or automatically would work--but it will have to be vented.

Mine just has windows that I open.
There is a brief time of the year when I must open them in the morning and close them at night, but most of the summer they just stay open.
 
Posts: 226
Location: South central Illinois, USA
2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

What Adam says sounds right to me, unless you're talking about winter only. In winter, you mebbe can get away with no, or very little venting. Our solar growhole is sorta dug into a hillside, and requires only a bit of venting in winter. We're close to St. Louis, so in summer, we don't raise anything in there... Too hot!

Used to be, there were these gizmos that would open and close vents w/o electric. Never seen one up close, but that would be something to look into...

Best of luck to you! TM
 
Posts: 268
Location: Colo
3
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I had a 6'x8' greenhouse kit at my old house in N Colo. Even with the door open and an automatic vent, the temps were approaching 145f in the day during June. I had to string out an extension cord and mount a box fan attached to a timer.

It was a bit of hassle, but the greenhouse was useless without it.

I'm no expert, but thats my experience.
 
Nothing? Or something? Like this tiny ad:
Food Forest Card Game - Game Forum
https://permies.com/t/61704/Food-Forest-Card-Game-Game
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!