by modifying the heat collection, e.g. by defocusing or by changing the position of heat-receiving elements

Full Title

Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors (control arrangements F24S50/00) > Preventing overheating or overpressure (by draining the working fluid F24S40/60) > by modifying the heat collection, e.g. by defocusing or by changing the position of heat-receiving elements