Passive solar heated house in the high Himalayas

My housemate explaining passive solar heating at my house in the high desert. You can ask me for details if you have questions, because being only 3:45 minutes this video doesn't have much detail.

Hi Rebecca,

You're right, the technical details are missing from the video...

...could you post a drawing for the trombe wall of the house?

if the outside wall serves as the trombe wall, what is the internal construction of the wall itself (does the wall have different layers of materials or is it homogeneous)?

how does the attached greenhouse attach to the house?

how is one floor air vented to the other floors (if at all)?

I like the fact this is being done in Ladakh!  Some monks have used reflective metals to heat their monasteries....I would welcome any and all pics and diagrams you post

I don't have a picture or diagram of the trombe wall. It's seen at 1:45 in the video. It's just a half-trombe wall. The downstairs south-facing wall is rammed earth, like the rest of the house, with windows that are not very large since the real winter glazing for the downstairs is the seasonally attached greenhouse. Upstairs, the south wall is largely windows, with a concrete-block wall up to only 2.5 feet high (the half-trombe wall), inside the floor-to-ceiling window, to absorb, store and moderate some of the sun's direct radiation. In the video at 1:10 and 1:45, Rohit is sitting on it. It's about 6 inches thick (because the standard cement or earth bricks in our area are 6x6x12 inches). It's painted black on the outside, facing the glass, to increase heat absorption from the sunlight. There is a 5- or 6-inch gap between the wall and the window -- That might not be ideal thermally, but I've lived with these type of half-trombe walls at our school for over 20 years, and being able to stick your arm inside for cleaning or maintenance is important. The beam above those windows is a reinforced concrete beam, because the roof is earthen and very heavy. All other lintels in the house are wood.

The greenhouse is attached to an iron frame with a type of long wavy wires called "clips" (I'm sure there's an American term but I don't know it) that you wedge into a narrow aluminum gutter that is bolted to the iron frame. It takes a small crew, at least 4 or 5 people, to put it on in November (excuse for a party to invite some of my former students), but only takes 30 minutes if at least one person knows how to do it. You hang the piece of UV-resistant plastic out over the top of the frame, pull it tight along the top, and wedge the "clips" (wavy long stiff wires) into the top edge of the frame, locking the top of the plastic in place. Then it's pretty easy to go down and clip the sides. We fix the bottom with a trench and soil, rather than clips. It is said to be helpful to to attach the greenhouse on a hot midday, when the plastic is as stretched and flexible as it's going to get (though maybe the metal frames expand more so maybe it doesn't matter). It takes only two people to remove the plastic in springtime.

The floors are not vented to each other, especially in winter, when the thermal buffer zone, ie stairwell and the east-west corridor along the north edge of the house, is closed off from the south facing rooms. The upstairs rooms do get a bit too cold at night in winter, these first two years, below 10C, which is not very nice. I was away for January this year, and I slept down in the living room for January last year, as did Rohit this recent January while I was away. I arrived on Feb. 8th and the house started warming up within a few days, and is comfortable even upstairs now, in late February.

The roof insulation is not great and I'm planning to improve it. It's only natural "straw-clay," about 6 or 8 inches thick. There's a gap 8 inches thick between the horizontal joists, hidden by the thin wooden ceiling, and I'm planning to put some more serious insulation in those spaces this year. I think it will make several degrees of difference. If the upstairs bedrooms stay above 12C on January nights, I'll be happy.

Thank you! my brother would probably like your passive solutions better than mine since these solutions here are barely even noticable parts of the house!

If I get it right, the corridor with the stairwell and storage space then acts as an unheated heat envelope.  It serves to buffer the inside warm living space from the outside more extreme cold temperatures, while still being useful indoor space.  Pretty great design!

Rebecca,  the north side corridor  has a sink and a washing machine(?) ,is the water supply  not effected by the cold?

My guess is that even though this part of the house is unheated, the attached heated part shares some heat with it, enough that it does not freeze.  

Right, the whole north side of the house is the unheated "thermal buffer zone": corridor, stairs, dry composting toilet, and storerooms. It does go down close to freezing, but in January (while I was away) this year it actually touched freezing according to the thermometer, so my housemate would run some water in the corridor sink whenever he passed it at night, and these indoor pipes didn't freeze or get blocked. It was an unusually cold and cloudy winter.

I'm planning to insulate the roof better this summer, and maybe put plastic over those corridor windows for the coldest month, and then I think the corridor will never go close to freezing again.

Ooh, I found some pictures that will help.

In summer with the plastic removed from the greenhouse frame, it can't overheat and cook the plants. I find it best to put the plastic on in mid-October and remove it in late April or even early May. Seedlings and cold-weather plants tend to get roasted on sunny days in April if we don't remove it, but tender seedlings can still get zapped by frost in May if we do. I try to cover tender seedlings at night after the greenhouse is removed, but of course mistakes get made...