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

Father & Son


Big’Un & Archimedes

Big’Un, on the left, is the son of Archimedes and Big Pig. I was working on setting up the greenhouse pillar forms when I saw them posing so nicely. I walked over to the crest of the hill to snap this photo. Then I saw why they were looking down towards the road…

Oops, not the case – see here Turns out Archimedes is Big’Un’s step-father of sorts.


How it’s hanging…

Spot had noticed I left the gate open when I brought in the pillar forms for the greenhouse concrete pour. He was headed down the hill at a good clip to check it out.

Outdoors: 37°F/31°F Cloudy, drifting snowflakes
Farm House: 59°F/54°F GH1 Pillar bases set, 1 round bale to north
Tiny Cottage: 68°F/65°F