Passively heated and cooled house
This is a resurrection of an idea I had first in 2010. The gist of it is that I've got what I think is a solid plan for a house that both heats and cools itself passively, mostly just with the energy of the sunlight falling on it. It takes advantage of the change in angle of sunlight between summer and winter to change where it puts the sun's energy, and uses the heat to drive airflow in the summer, and just passively stores and radiates it in the floor and walls in the winter.
The drawing above is designed for the latitude of central New Mexico, about 35° N. It's also only a plan that will work in places that get a large amount of sunlight year-round. If it's often cloudy where you live this thing just won't work -- especially in the winter.
The linchpin of my house idea is the way it is broken into two levels, one on top of a hill and one on the north side. Doing this allows the entire house to benefit from warmth of shallow winter sun, while at the same time shielding the living room and kitchen from the harsh but high summer sun.
Allowing the summer sun to beat down on the upper level in the summer does serve a purpose though. Having two levels, one of which is exposed to sun while the other is not, should create a big heat gradient. Opening vents at the top of the house and the base of the north wall should cause a decent amount of air to be drawn from the cool, shaded north side through the house and out the top.
If I then have a lot of vegetation around the north vents and/or a fountain in the living room in front of them I can actually use the heat of the sun to cool my house for free!
How those same skylights warm the house in winter should be obvious, but I'd like to put a wood stove on the lower level for good measure anyway. Even if I don't need it all the time it's great to have a fire to sit next to.
The idea is then to have the kitchen and living room on the bottom and the bedroom and bathroom at the top.
Then in winter the bedroom and bathroom will be warmest at night, while the living room and kitchen capture enough sun to be pleasant in the day.
In the summer the living room and kitchen are shaded and cool in the day, using the heat in the upper level to ventilate them. Then at night all that heat goes flying out the top leaving the bedroom with a warmth that should be pleasant in our surprisingly chilly desert nights.
In the fall and spring you don't have to worry about climate control around here because it's just so unbearably pleasant all the time.
The other cool idea I had was to build a cellar under the bedroom, and then build the kitchen cabinets into the wall so that they open into the cellar as well as the kitchen. Then we can stock the cabinets from the back while standing in the pantry...like a supermarket!
The overall budget for building and equipping this house is looking like $20,000 to construct and equip with state of the art appliances an extremely efficient 600 square foot home (not counting the cellar).