That’s the extension to the St George’s School, Wallasey, Cheshire, designed in 1959.
The south wall of the building is nothing but glass, and the floors and walls of the building are made of very thick masonry and concrete which absorbs heat on sunny days and releases it on cold days.
Obviously the lighting and heat emitted by children in the building contribute to heating the building.
A book on solar heating, “Your Solar Energy Home” by D.Howell says (p.12), “When architect A.E.Morgan designed the building, higher authority insisted he include a boiler. Imagine what a delicious day it was for Mr Morgan when after four years occupancy and not a day of use from the boiler, he was allowed to remove it.”