A small solar engine is used for water pumping in a desert area. Water is the working fluid.

Water enters the pump as saturated liquid at 50°C and is pumped up to 2 bar by a small centrifugal pump. The boiler evaporates the water at 2 bar, and saturated vapor at this pressure enters a small expander. The steam leaves the expander at 50°C and with a liquid fraction of 6%, and is subsequently condensed. The mass flow rate is 140 kg/hr and the pump is driven by a 0.4 kW motor. Determine the power output of this solar engine, the energy conversion efficiency taken as the net shaft work output divided by the energy transfer as heat to the fluid in the boiler, and estimate the area of the solar collectors, assuming the collectors can absorb 800 W/m². Use the tables in Appendix A.3 for data.

Data From A.3

A Boiler Feedwater pump Turbine Condenser M Generator G n Qc