This research paper from 2006 looks into a simulation exercise of solar thermal systems consisting of uncovered solar collectors and/or air-to-water heat exchangers. The aim is to optimise their functioning and to compare the performances. This simulation has been carried out for the district heating net in Bishkek, Kyrgyzstan.
The simulation of this so-called multicomponent solar thermal system looks into a method to preheat cold water by using solar irradiance as well as heat of the ambient air.
It is concluded, among other points, that the investigated systems can achieve high energy gains in a cost efficient manner.