Design of a Solar-Power Generator
A solar power system capable of heating water into steam to power a turbine/ generator needs to be designed. The problem definition includes the following information and system requirements:
• Each second, 0.9 kJ of solar energy strikes a square meter of ground.
• The target value for the real efficiency of this system is 26%.
• The system needs to produce an average of 1 MW of power during a 24-h period.
• The heat engine releases its waste heat into the surrounding air.
(a) Design a solar power system to fulfill these requirements. (b) Assuming the resulting steam powers an ideal Carnot heat engine that operates between T _{l} =25^°C and T_{ h} = 400^°C, calculate the upper bound on efficiency for the engine.
Approach
Following the general design process introduced in Chapter 2, we will first develop any necessary additional system requirements. Then, we will develop conceptual alternatives and converge on the most effective option.
We will then determine the more detailed geometric specifications of the system. Lastly, we will use Equation (7.13)
\eta _{c}=1-\frac{T_{1}}{T_{h}} (7.13)
to calculate the efficiency of the proposed engine.