It's amazing what creative designs are dreamt up prior to having AC as a crutch, including examples much older than that. For example, water pools in the centre of Roman courtyards[1], which lowered the temperately passively. Another example are windcatchers common the Middle East[2].
[1] https://en.wikipedia.org/wiki/Impluvium
[2] https://en.wikipedia.org/wiki/Windcatcher
[3] More examples: https://engineeringrome.org/2022/09/26/methods-of-temperatur...
I think I have seen a primitive but very effective heat exchanger in an old house. Normally, when you have a stove and chimney and hot gasses escape the house you also have a lot of cold air rushing in. In this house the hot air was directed around the whole length of the chimney and then through the mass of bricks that formed the stove so that the air coming in was already warm.
This allowed to very efficiently keep the entire house very warm while also nicely ventilated even in very, very cold weather with very little wood needed.
