The Geothermal Power Station · AI Generator #GEN-CC8C79E1

Physics · thermodynamics

Problem

A geothermal power station operates by extracting hot water from underground reservoirs and using it to drive a heat engine. The station pumps water from a geothermal well at temperature Th=180°CT_h = 180°\text{C} and rejects waste heat to a nearby lake at temperature Tc=15°CT_c = 15°\text{C}. The power station is designed to extract Qh=50  MWQ_h = 50\;\text{MW} of thermal energy per second from the geothermal source. (a) What is the maximum theoretical electrical power output of this geothermal station? (b) In practice, the actual power station achieves only ηactual=12%\eta_{actual} = 12\% efficiency. How much waste heat per second does the station dump into the lake? (c) If the lake has a volume of V=2.0×106  m3V = 2.0 \times 10^6\;\text{m}^3 and the station operates continuously, by how much would the lake temperature rise per day if there were no other heat transfer mechanisms? (Use ρwater=1000  kg/m3\rho_{water} = 1000\;\text{kg/m}^3 and cwater=4180  J/(kg⋅K)c_{water} = 4180\;\text{J/(kg·K)}.)

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