Reddit mentions of The Solar greenhouse book

There's an out-of-print book simply called "Passive Solar Energy." It's got lots of great information; I bet it will be just what you are looking for as far as the physics of solar energy and thermosiphoning (which is essentially "heated fluid rises because it's less dense than cooler fluid"). I'm an engineer and I really think that book gives you all you need to know to have a basic working knowledge of solar heat gain and how various systems of solar energy capture operate. Here's a list of books I have found helpful and/or interesting in regards to solar energy:

• Passive Solar Energy - The top link is a link to pdf's of the chapters of the book.
  
  
• The Passive Solar Energy Book - VERY in-depth on passive solar theory, design, and construction.
  
  
• Solar Air Heating Systems - Another design and construction book, specifically about solar air heating.
  
  
  
• The Solar Greenhouse Book - Name says it all. It's all about passive solar greenhouses.
  
  
• A Golden Thread - Really interesting book about how man has worked with the sun in building design through the history of civilization.
  
  
  For earthships/earth-sheltered homes, I recommend these books:
  
  
• Earth-Sheltered Housing Design - One of the most detailed and complete books on earth-sheltering available. Not earthships, but the same ideas apply.
  
  
• Earth-Sheltered Houses - Another essential book for earth-sheltering houses. Author has built several of his own and remains an authority in the subject as well as cordwood building, for which he has also written books.
  
  
• Earth-Sheltered Solar Greenhouses - Combines two subjects for a very Permaculture-appropriate building technique.
  
  
• Earthship Vol I and II - Needs no explaining.
  
  
  From my experience in university studying fluid dynamics, I recommend not going any deeper into the subject than what you would find in the solar energy books I listed above. The subject is math-heavy, and the academic study of the topic is not going to help you with what you are interested in with permaculture. It's kind of like studying the abstract physics/math of electromagnetism when all you want to do is wire a house.
  
  Hope this helps!