A Prototype Steam Storage System for Power Production

Use of solar energy on a large scale is mainly limited to the sun duration hours, weather conditions and adequate solar thermal storage technology. A means of addressing this problem using local materials is provided. A prototype pressure storage system was designed using auto cad 2010 and fabricated using locally available materials. The steam storage system was tested using ASME 2000b guidelines for boiler and pressure vessels at a small scale. The maximum continuous rating for the storage system was 60 kgh^-1 maximum instantaneous demand 40 kgh^-1 , storage capacity 50 kgh^-1 and mean off peak load of 100 W was realized. The maximum test temperatures of operation obtained using seamless galvanized iron pipe was 264.7°C and 140°C using polypropylene pipes. The steam storage system operated between 1.0×10⁵ Pa and 1.0×10⁶ Pa. Its charging duration was twenty minutes and would discharge at the rate of 50 lh^-1 continuously after full charge with solar irradiance between 800 W/m² and 1020 W/m². The length of complete discharge for the heat transfer fluids was found to range between 4.4 hours and 6.9 hours. The power output for the heat transfer fluids were in the range of 251.8 W and 486.9W. The steam storage system was found to have an efficiency of 93.5% and a thermal capacity of 4.54×10³ kJ. This system presents a means of storing solar energy in form of steam during low energy demand and its conversion to power during high peak demand twenty four hours a day depending on the size of the storage and application and hence addressing the problem of variability and low density of solar energy.