The chinese passive solar greenhouse uses the sun’s heat more efficiently than a regular greenhouse.
It’s built to very specific dimensions and contains reflective surfaces, thermal curtains and solar heat absorbers such as water barrels and concrete blocks which absorb heat during the day and dissipate it again at night time.
These greenhouses are becoming popular because they don’t require additional heating, like many small scale greenhouses and most large scale commercial greenhouses.
These greenhouse farmers were able to grow tropical plants in January in the fairly cold state of Missouri in their very well designed passive solar greenhouse.
The best guide to a passive solar greenhouse is from the missouri agricultural extention, the same place these photos are from. See http://aes.missouri.edu/bradford/education/solar-greenhouse/solar-greenhouse.php