Here's an extremely interesting academic paper that was published recently:
"Utzon and the sun path as an organizing element of life in a house"
by Miguel Ángel Rupérez Escribano, Universidad Politécnica de Madrid
Fourth International Utzon Symposium (2014)
Link to pdf
Danish architect Jørn Utzon is best-known, of course, for the design of the Sydney Opera house (and for the fractious collaboration with engineers from Ove Arup's office on that project). His Bagsværd Church (Bagsværd, Denmark, 1968-76) is also a masterpiece of world architecture in the late-modern period. What may be less well-known is that Utzon designed dozens of houses around the world.
If you're thinking that the image above looks quite a bit like George Fred Keck's solar houses of the 1940s, you're right, it certainly does. Escribano concludes that Utzon was influenced by some of the main characters in The Solar House, particularly Keck and Frank Lloyd Wright:
"The selected houses designed by Utzon follow a common pattern, which has remarkable similarities with the American solar houses."
Escribano's excellent study goes further, looking closely at how Utzon adjusted the solar orientation of many of his homes to the southeast or southwest based on site and climate factors.
Although Escribano says that Utzon considered the sun "a useful element in heating the house" in cold climates, the paper does not suggest that Utzon aimed to quantify energy savings, or to call his houses "solar," as Keck and Wright did.