Pressure Losses in Small-Sized Parabolic-Trough Solar Fields for Industrial Process Heat
Abstract
Using parabolic-trough solar collectors (PTC) for industrial thermal processes in the temperature range up to 300'C is not new (Fernandez-Garc a et al., 2010), but in the last five years there is a boosted interest in this type of concentrating solar technology. The Capsol project was born under this framework with the objectives of design, developing, and testing a new PTC collector prototype (Fernandez et al., 2010). One of the problems that arise when designing PTC solar fields is how to deal with the pressure losses which are particularly critical when producing saturated steam. Depending on the industrial process, the specific heat demand and the inlet/outlet process fluid temperatures, a solar field configuration can be feasible or not. For the case study presented in this paper, a sensitive analysis of a small-sized PTCs solar field loop is performed. The PTC selected is the Capsol collector, which has a focal length of 0.2m and an aperture area of 2 m2 (1mx2m), and its steel absorber pipe has an inner diameter of 15 mm. From the results obtained, it is possible to conclude which loop length and nominal working conditions would be optimal. The study has been done considering the production of pressurized hot water and saturated steam.