Sensitivity Analysis of Saturated Steam Production in Parabolic Trough Collectors

Thermal and synthetic oil is the most common fluid used as heat transfer fluid in parabolic trough collectors for steam generation or producing high volumes of hot water. The solar field configuration using oil is the unfired-boiler configuration. The use of water as alternative heat transfer fluid is not new but is not extended. This paper presents numerical results related to the thermal-hydraulic behavior of solar fields producing saturated steam for industrial process heat applications considering two different types of small sized parabolic-trough collectors which are available in the market. A sensitivity analysis was conducted considering different design criteria and working conditions. The effect of inlet water pressure, temperature and DNI is analyzed. One of the conclusions extracted from the numerical results is that low working pressures can originate high pressure losses in the solar field depending on the absorber pipe diameter and steam pressure and, consequently, steam temperature in the solar field outlet can vary a lot even under small transients.