Abstract
In the work, the temperature field model is developed for the absorber of a round-pipe collector. As distinguished from previous models when the temperature of liquid was assumed to be constant over the entire pipe crosssection, the results obtained clearly show the temperature variations in the absorber’s cross-section. In the work, optimal values are found in the work for geometrical parameters of the collector (i.e. the plate thickness and the pipe diameter) that allow the highest possible temperature of liquid to be achieved.