Transition time effects in collector systems coupled to a well mixed storage

Using analytical methods it is shown how transition times of fluids in collector arrays and system piping affect energy collection in solar systems with a well mixed storage tank. To a very good approximation this effect can be accounted for by a reduction factor multiplying the collector heat removal factor, F_R. The effect is important especially for systems with a small ratio of storage volume flow rate to collector area, systems with a large fluid volume in the collectors and system with long connecting pipes. These all can be characterized by fluid transition times through collectors or piping which are not negligible relative to the fluid transition time in the storage tank. Such systems may appear as viable candidates in Industrial Process Heat applications.