Consider a binary geothermal cogeneration plant like that in Fig. P18-94 using geothermal water at 165oC with

Question:

Consider a binary geothermal cogeneration plant like that in Fig. P18-94 using geothermal water at 165oC with isobutane as the working fluid. The mass flow rate of geothermal water is 175 kg/s and the net power output is 6.9 MW. It is determined that geothermal water leaves the plant at 85oC (state 6) and leaves the heater at 65oC (state 7). The fresh liquid water, heated to 75oC (state 9), is used for space heating and returns to the cogeneration plant at 50oC (state 8).
(a) Determine the rate of space heating provided by the system and the mass flow rate of water used for space heating.
(b) Determine the thermal efficiency of the power plant and the utilization factor for the entire cogeneration plant.