Solution Found!
Answer: An experimental power plant at the Natural Energy
Chapter 20, Problem 45P(choose chapter or problem)
Problem 45P
An experimental power plant at the Natural Energy Laboratory of Hawaii generates electricity from the temperature gradient of the ocean. The surface and deep-water temperatures are 270c and 60c respectively. (a) what is the maximum theoretical efficiency of this power plant? (b) If the powerplant is to produce 210 kW of power, at what rate must heat be extracted from the warm water? At what rate must heat be absorbed by the cold water? Assume the maximum theoretical efficiency. (c) The cold water that enters the plant leaves it at a temperature of 100c. What must be the flow rate of cold water through the system? Give your answer in kg/h and in L/h.
Questions & Answers
QUESTION:
Problem 45P
An experimental power plant at the Natural Energy Laboratory of Hawaii generates electricity from the temperature gradient of the ocean. The surface and deep-water temperatures are 270c and 60c respectively. (a) what is the maximum theoretical efficiency of this power plant? (b) If the powerplant is to produce 210 kW of power, at what rate must heat be extracted from the warm water? At what rate must heat be absorbed by the cold water? Assume the maximum theoretical efficiency. (c) The cold water that enters the plant leaves it at a temperature of 100c. What must be the flow rate of cold water through the system? Give your answer in kg/h and in L/h.
ANSWER:
Solution 45P
Step 1
a) Equation for maximum theoretical efficiency is, η = 1 - (TC /TH)
Where, TC - temperature of the cold reservoir
TH - Temperature of the hot reservoir
TC = 6℃ = 273 + 6 = 279K (Provided)
TH = 27℃ = 273 + 27 = 300K (Provided)
Therefore, maximum efficiency, η = 1 - (279K /300K)
η = 1 - 0.93 = 0.07 or, η = 7%