Solid State Ventilator

I designed an air circulation system [1,2] for our tiny cottage that uses no moving parts. Think of it as a solid-state fan. It is driven by thermo-siphoning through the block wall behind the wood stove and chimney where the sun also shines. The hotter the wall, from wood burning or passive solar gain, the faster the air flows.

Until now the system had remained closed and the temperature differential between the floor and the top of the cottage 11′ above was typically about 10°F, sometimes more. This made the kid’s loft rather warm, often reaching 78°F which is to hot for comfort for us hot blooded Vermonters – we melt.

Will jack hammered open the base of the three air tubes this weekend which allowed the air circulation system to begin operating. The temperature differential between the floor and ceiling is now just a couple of degrees. Pretty impressive for a system that uses no electricity to power the circulation.

The air pipes in the ventilator have their lower openings at three different heights in three different rooms. The lowest one pulls air from the lowest point of the cottage in the fire wood bin under the stove. This causes air to flow past the wood continually drying it. Otherwise we might get air stagnation and some mold there. The next one up pulls air from the master bedroom floor. This catches the coldest air from our toes and lifts it up past the warm masonry to the ceiling. The third tube sucks air midway up the kitchen wall, 180° away from the bedroom vent.

Currently the ventilation system is not hooked up to our earth air pipes. When I make that connection it should further increase the efficiency of the system. I like to test things slowly so I can observe how each component works before connecting them.

I like simple systems. They take longer to think about and design but in the long run they save time and resources. No electricity. No maintenance. No whirring fan noise. Nothing to break down. I will admit that I designed the system so I can add energy efficient computer style fans if it didn’t work out the way I wanted. Always have a backup plan!

Outdoors: 31°F/30°F Cloudy, Drifting snowflakes
Farm House: 59°F/55°F First pillar form placed
Tiny Cottage: 66°F/65°F

About Walter Jeffries

Tinker, Tailor...
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5 Responses to Solid State Ventilator

  1. pablo says:

    Maybe I missed a post. Are you guys living in the cottage now?

  2. “Maybe I missed a post. Are you guys living in the cottage now?”

    Pablo, we moved in last Christmas Eve of 2007. We’ve been enjoying sleeping up there and other stuff since. Our shower has still been down at the old place. The transition is gradual. The old farm house is getting used more and more for farm work stuff and less and less for home.

  3. donald says:

    Evening Walter – first and foremost thanks for your blog. I truly appreciate your sharing of knowledge. I would also like to thank you for helping me think outside of the box in terms of feed. I moved onto my current farm about a month ago from a farm where we gave our four pigs a constant supply of grain which adds up fast. Since i’ve been on frog belly i have made connections with a local cheese maker for whey and bakery for old bread and it has made a difference. Our three yorkshires raised on an acre are healthy, happy, and are putting on weight. I think its from my TLC, in part at least. We are planning on expanding our herd and I was wondering if you had any advice on breeds? I was thinking chester white sows and berkshire boars and sows to begin with. I also wanted to ask your opinion on how many pigs should one reasonably raise per acre. We have enough land to keep all happy so that’s no problem. Thanks again.

  4. Donald, on breeds I enjoy having the mix of colors to see in the field but when it comes to slaughter I prefer blonds. For mothering, fast growth and large size the Yorkshire, which is the base of our herd, is supposed to be superior. For marbling the Berkshire, a component of our herd, is supposed to be superior. This is why we have mixed pigs and then select within them for the best of the best with each generation.. All that said, breed is a very personal choice, some people like one or the tother. There is also the whole issue of availability in your area of breeding stock.

    A sow should not be creating a stink in the summer, or any other time of the year in particular. If you live in suburbia people may smell with their eyes creating that problem but otherwise I would not expect a herd on pasture to make a problem for you and your neighbors.



  5. Oops, I answered part of someone else’s question here. I had meant to refer you to this post about pigs per acre.

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