AskCodeMan

I'm designing an active solar house. In winter, the heat collector on the roof will produce hot air, which will be blown into the floor. In summer, the air blown into the floor will come from a vent in the north eave. When not needed, the hot air will be blown into a drying closet, or if that's already hot enough, outside. This needs some valves, at least one of which must be electrically controllable (the other can be flipped twice a year, but I'd prefer it be electrically controllable too). Do such valves exist?

I'm not sure about air valves such as you are speaking of - I did a quick Google search and did not find anything referring to air valves like that, although I am sure some other air valves could be adapted to that use.

That said, though, I believe your solar system would be more efficient collecting solar heat gain in water with anti-freeze and the transport/movement of the heat via moving water would be more efficient. I also believe you will find more information and system design, along with parts and equipment, on transferring the heat around with water.

I found a possible candidate on Price HVAC, though I don't understand their jargon well enough to tell.

The air, when heating, will be recirculated, so it should work as well as a conventional system that blows air through coils. The temperature will be steadier because of the thermal mass.

I think I'm going to blow cold air at the walls, rather than through the floor. That way I'd be walking on a warm floor even while cooling the house.

When it's hot out, walking on a nice cool floor makes you feel cooler.

Of course, much of the heat gain is through the wall, which is why most air conditioning systems blow the air toward the walls - cool the air coming in off the walls and the inside feels cooler, basically, if you keep the walls at a given temperature, then the temperature of the space within those walls feels more even.

When cooling, air flow helps you feel cooler; when heating, the air flow also makes you feel cooler (think of it as very slight wind-chill, same basic principle).