Abstract: The invention relates to a solar collector assembly comprising a hollow housing body that is at least partially transparent. An absorber means is contained in the housing and a vacuum pump means is connected to the housing. A particular process of operating the solar collector assembly also forms a part of this invention.Solar collector assemblies are used for converting sun energy into other forms of energy such as heat used to prepare hot water or heat for energy production. Many attempts have been made to design solar collectors having a compact structural shape and satisfactory efficiency to render them suitable as an energy source in dwelling houses. However, such a solar collector has not yet been attained.