Analysis of Vacuum Evolution Inside Solar Receiver Tubes

In parabolic trough technology,the components used as solar receptor is formed by a steel tube confined inside a glass chamber.The space between both tubes is evacuated during the manufacturing process in current concepts.A new concept of absorber tube, currently under demonstration stage, HITECO, is based on the concept of dynamic vacuum, where the gas evacuation is produced in the solar field during the start up.The gassing and the outgassing processes are the main mechanisms controlling the equilibrium pressure and the gas composition in high and ultra-high vacuum systems. In the solar absorber tubes the mechanisms thatcontrol the condition inside the vacuum chamber are adsorption, absorption, desorption, permeation and leakage. All these phenomena have been analyzed in detail in current paper in order to define the performance evolution of absorber tubes placed in commercial solar fields.