Does a courtyard improve comfort?
Courtyards have been built next to private houses for thousands of years. According to wikipedia, houses with a central courtyard were built in ancient times in China (siheyuan), Rome (domus), the Middle East and the Andes.
Courtyards are private open spaces shielded from public view and intrusion. They are often decorated, planted and furnished for quiet enjoyment.
Courtyards have various functions, but my interest is in one function only: the control of climate for human comfort, both within the courtyard and within the house. I hope members will want to share ideas, techniques and projects for using a courtyard in this way.
As I mention below, courtyards do not always improve climate control. Perhaps some members may have experienced courtyards that perform poorly, and what can be done to correct that.
Baruch Givoni's work
The authority in this field is Baruch Givoni. In his textbook "Man, Climate & Architecture" (1969, 1981) he explains the principles that apply, but does not analyse the use of courtyards. His later book "Passive and Low Energy Cooling of Buildings" (1994) does analyse courtyard performance. The final chapter "7. Cooling of Attached Outdoor Spaces" (pp.239-257) contains a wealth of advice.
Givoni's work, as shown by his chapter title (and book title), is concerned mainly with making courtyards cooler in hot, dry climates. Readers of this forum who plan to live where summers are hot and dry may consider enclosing courtyards if they can be kept cool without much energy use. In that chapter Givoni does not pursue the idea that a cool courtyard can be the source of cold air to cool the house during summer nights (nocturnal ventilation, or night purge). In other chapters he discusses nocturnal ventilation using cold air from various sources.
Givoni cautions that the use of courtyard houses through millennia in desert regions does not mean that a courtyard always improves comfort there. The passage can be found by searching (One time only!) on "givoni issues specific to adjacent outdoor spaces".
Other authorities
I have not found any detailed advice on designing or using a courtyard for climate control except that of Baruch Givoni. Steve Szokolay, in "Introduction to Architectural Science" (2004), page 68, recommends attaching courtyards to Australian houses in "hot-dry climates". His brief review echoes the advice of Givoni.
It is strange that no courtyard tradition exists in Australia, since several of the climate zones are especially suited to them. The authoritative web-site "www.yourhome.gov.au" is dumb on this topic.
Nick Hollo's book "Warm House Cool House" has a section on "Courtyard Houses". He says: "It is particularly beneficial in arid areas, where the courtyard can nurture a lush garden in contrast with the harsher surroundings, and provide cooled and moitened air to adjacent rooms." Here and elsewhere in the book he cites examples of houses with courtyards. To my mind, hardly any of them would function well enough to change the indoor climate.
My courtyard project
Recently, I had the small courtyard shown here built around the back door on the south side of my house. Every feature of this courtyard was intended to improve the climate indoors.
I have described the courtyard, with photos, and explained its function in my blog:
https://climatebysurly.com/2016/07/21/my-heat-control-courtyard/
There is much more about it on a special page:
https://climatebysurly.com/my-house-page/a-heat-control-courtyard/
I am monitoring its performance with thermometers, and will report the results as they come to hand.