4 - Nontracking solar collection technologies for solar heating and cooling systems

Abstract

This chapter presents a review of nontracking solar thermal collectors. These collectors are suitable for low to medium temperature applications with a maximum of about 150°C. This range of temperatures is particularly suitable for solar heating and cooling applications. Usually these collectors collect both direct and diffuse solar radiation, so they are very effective collection devices. For this purpose there is no requirement to follow the sun trajectory during the day so they belong to the nontracking collectors. Some of the types presented may require seasonal tracking, ie, changing the tilt angle of a collector a few times per year. The frequency of tracking increases with the concentration ratio. Higher concentration ratio leads to higher collector operating temperature but also to higher tracking accuracy requirements. The types of collectors examined in this chapter are the flat plate collector, which is the most used collector type, and its variations, the diffuse reflector, reverse flat plate collector, compound parabolic collector, and evacuated tube collector.