Low-cost orientation system for a concentrating solar collector with static reflector and tracking receiver

Abstract

A solar linear concentrator with a fixed reflector and a moving focus is under development. The main objective of the research is to develop a low – cost, roof integrated, solar collector suited for mid – range thermal applications, such as absorption cooling and industrial heat (90 – 200 ºC). This range of temperatures could be achieved with low concentration factors (9 - 15 suns). This range of radiation concentration is also well suited for the development of Combined Solar Heat and Power (CHP) systems integrating PV and thermal converters in the same unit [1]. Recently, this kind of application has gained much attention from the solar energy industry with several interesting development projects from both the industry and the academy [2]. The proposed solution is based on a static reflector with a moving linear focus (Figure 1). The basic geometric concepts were developed in the ‘70s [3] but the product development never passed beyond the experimental prototype stage. Nevertheless, a detailed ray-tracing modelling of the reflector behaviour shows clearly that it is possible to achieve a high optical efficiency into the target concentration range. Although the reflector is static, the sun path should be tracked by the receiver to be kept on the reflector focus. Therefore a precise and inexpensive tracking control system is of fundamental importance for a successful development of the collector