It is proposed that solar energy be used to warm a large collector plate. The energy would in turn, be transferred as heat to a fluid within a heat engine, and the engine would reject energy as heat to the atmosphere having assumed temperature of 20°C. Experiments indicate that about 1880 KJ/m²h of energy can be collected when the plate is operating at 90°C. The minimum collector area that would be required for plant producing 1 KW of useful shaft power will be approximately

Question

Question

Download Solution PDF

It is proposed that solar energy be used to warm a large collector plate. The energy would in turn, be transferred as heat to a fluid within a heat engine, and the engine would reject energy as heat to the atmosphere having assumed temperature of 20°C. Experiments indicate that about 1880 KJ/m²h of energy can be collected when the plate is operating at 90°C. The minimum collector area that would be required for plant producing 1 KW of useful shaft power will be approximately

This question was previously asked in

BPSC AE Paper IV General Engineering 19 Dec 2024 Official Paper

Attempt Online

View all BPSC AE Papers >

15 m2
30 m2
10 m2
20 m2

Answer 1

Concept:

The collector absorbs solar energy to operate a heat engine. The maximum efficiency of the engine is given by Carnot's principle. The useful power is calculated by multiplying collected solar power with Carnot efficiency.

Calculation:

Source temperature: \( T_h = 90^\circ C = 363~K \)
Sink temperature: \( T_c = 20^\circ C = 293~K \)
Collected solar energy: \( 1880~kJ/m^2 \cdot h = \frac{1880000}{3600} = 522.22~W/m^2 \)

Carnot efficiency:

\( \eta = 1 - \frac{T_c}{T_h} = 1 - \frac{293}{363} = 0.1939 \)

Useful power per m²:

\( 522.22 \times 0.1939 = 101.28~W/m^2 \)

Required power output: 1 kW = 1000 W

\( \text{Area} = \frac{1000}{101.28} \approx 9.87 \approx 10~m^2 \)

Download Solution PDF

Question

Answer (Detailed Solution Below)

Detailed Solution

More Performance of Heat Engines and Reversed Heat Engines Questions

More Second Law of Thermodynamics and Entropy Questions

More Thermodynamics Questions