ABSTRACT
Solar heat collectors may be classified according to the type of insulation, degree of concentration of sunshine, and nature of orientation. The engineering literature indicates that most of the possible combinations of insulation, concentration and orientation of solar heat collectors have been tried at one time or another. Concentration may vary from unity in flat-plate collectors to successively higher values as reflectors are employed in the shape of cylindrical parabolas, truncated cones, or paraboloids. F. A. Brooks has studied several types of natural-convection solar water heaters in use in California, and gives some quantitative data on performance but no correlation with measurements of solar intensity. Most domestic solar hot-water heaters depend upon natural circulation, with the tank above the collector level. The heat loss through the bottom of the collector boxes may be calculated by conventional methods; by use of sufficient insulation it may be made as small as is consistent with the value of the heat saved.
