Reference no: EM132361365

Question - A small solar power station is being designed. A low boiling point working fluid is to be pumped to 450m² of glazed flat plate solar collectors. The vapour which is formed in the collectors and the remaining liquid are passed to a separation vessel. Here the vapour rises to the upper part of the vessel then passes to a turbine that drives an alternator. The liquid remaining in the vessel and liquid returning from the turbine's condenser are fed back through the collectors. In the event of there being no demand for electricity a mechanism is activated that repositions the collectors such that they face away from the sun. The collectors and drum are situated over a large concrete area for which there is no risk of fire. The vessel and collectors have a design pressure of 1200kPa gauge. When operating at the saturation temperature corresponding to this pressure, the solar collectors are 75% efficient in their conversion of solar energy to heat in the liquid/vapour. The peak rate of solar energy flux (direct and reflected) at this location is 1.3 kW/m².

a) In the event of their being no demand for electricity and the collector repositioning mechanism failing, determine the required vapour discharge rate, in kg/sec, of the safety valve fitted to the separation vessel.

(b) Select an appropriately sized and set "FIG 1541" safety valve from the catalogue data provided on the next page (which shows gauge pressure) Give clear reasons for your choice.