Green's function solution of the time-dependent solar collector problem

The Green's function for the time-dependent solar collector problem is derived and examined. It is found that the influence of a point source of irradiance propagates with the speed of the heat transfer fluid. This result contradicts some earlier work.An analytical expression is derived for the output fluid temperature in terms of the irradiance as a function of position and time. Fluctuations in ambient and input fluid temperatures are also considered.