Within Arizona(USA) is a beautiful cliff-dwelling built by the Sinagua people in 1100-1425 AD. Montezuma Castle (renamed to this by colonizers) has around 20 rooms, and is built using a method that today people call “passive solar building.”
“In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unlike active solar heating systems, it does not involve the use of mechanical and electrical devices.” Wikipedia
For the cliff dwelling, that included a design that ensured the buildings were hit with the heat of the low-winter sun, but protected from the high-summer sun by overhang. It also made use of ventilation, small windows and doors (to reduce temperature loss), and more.
This ancient knowledge is making a comeback in houses, but is really helping for greenhouses. Even in colder climates where temperatures can reach -40c(-40f), passive solar designs are enabling greenhouses to run all-year.
More Info:
Is the “heat collection system” just barrels of water or something more complex? I know water can hold onto a lot of heat.
Yes, water is very common! Another option I sometimes see is rock incorporated into the build in some way (like a stone wall).
Here's an example:
Thick stone walls are magic, lots of older houses in southern France, Italy, Spain etc are built with them and it keeps them at a pretty stable temperature inside year round.