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Solar Energy Interview Questions and Answers for Experienced people on “Solar Refrigeration and Air-Conditioning Systems – 2”.
1. Solar air conditioning system uses _______ as its energy source.
a) sun
b) wind
c) electricity
d) motor
Answer: a
Clarification: Solar air conditioning system uses sun as its energy source. It is just like any other air conditioning system except that it uses solar power. A motor is not an energy source. Solar energy is converted to electricity to run the system.
2. Which of the following types of solar energy can be used to source air conditioning systems?
a) Passive solar and wind
b) Passive solar and photovoltaics
c) Vapour compressor and photovoltaics
d) Wind and solar thermal energy
Answer: b
Clarification: Passive solar, solar thermal energy and photovoltaics can be used to source air conditioning systems. Wind and vapour compressor are not types of solar energy.
3. What are the three heat exchangers used in an absorption type refrigeration?
a) Compressor, absorber and generator
b) Absorber, generator and adsorber
c) Absorber, regenerating intermediate heat exchanger and generator
d) Compressor, generator and adsorber
Answer: c
Clarification: The three heat exchangers used in an absorption type refrigeration system are absorber, regenerating intermediate heat exchanger and generator. These heat exchangers replace the compressor in a vapour compression refrigeration system.
4. What is the working fluid in vapour absorption type systems?
a) Platinum
b) CFCs
c) Freons
d) Ammonia
Answer: d
Clarification: Ammonia or lithium bromide is the working fluid in vapour absorption type systems. CFCs and freons are used in vapour compression type systems and are called refrigerants. Platinum is not used as a working fluid.
5. Absorption of ammonia in a liquid solution analogous to _______
a) condensation
b) evaporation
c) vapourisation
d) convection
Answer: a
Clarification: Absorption of ammonia in a liquid solution is analogous to condensation process. Evaporation and vapourisation concern with liquids turning into gas. Convection is a process of heat flow.
6. Which of the following best describes the process of vapour absorption refrigeration?
a) Absorbing fluid vapour into liquid carrier → producing vapours from solution by heating → thus cooling → pumping into a high pressure cycle
b) Absorbing fluid vapour into liquid carrier → pumping into a high pressure cycle → producing vapours from solution by heating → thus cooling
c) Absorbing fluid vapour into liquid carrier → thus cooling → pumping into a high pressure cycle → producing vapours from solution by heating
d) Absorbing fluid vapour into liquid carrier → producing vapours from solution by heating → thus cooling → pumping into a high pressure cycle
Answer: b
Clarification: The working fluid is absorbed into a liquid carrier which is then pumped into a high pressure cycle. This cycle produces vapours from solution by heating thereby cooling.
7. Which of the following use absorption refrigeration system?
a) Heating systems
b) Solar cooker
c) Waste heat from cogeneration
d) Solar stills
Answer: c
Clarification: Absorption refrigeration systems are used in large commercial and industrial installations. For instance, waste heat from cogeneration or process steam plants.
8. Which of the following is/are considered for calculating the overall efficiency of solar absorption refrigeration system?
a) Coefficient of performance of absorption system
b) Solar collection efficiency
c) Solar insolation
d) Solar collection efficiency and coefficient of performance of absorption system
Answer: d
Clarification: Solar collection efficiency and coefficient of performance of absorption system are considered for calculating the overall efficiency of a solar absorption refrigeration system. One can assume the solar insolation to be fairly constant and hence does not contribute towards efficiency calculation.
9. What is coefficient of performance?
a) Ratio of refrigeration capacity to input solar energy
b) Ratio of input solar energy to refrigeration capacity
c) Product of input solar energy and refrigeration capacity
d) Ratio of refrigeration capacity to input electrical energy
Answer: a
Clarification: Coefficient of performance can be defined as the ratio of refrigeration capacity to input solar energy. It basically describes the efficiency of the refrigerating system as it compares the input to output.
10. In solar vapour compression cycle, efficiency of Rankine cycle increases with _______
a) decrease in temperature of heat exchanger
b) increase in temperature of heat exchanger
c) the amount of heat supplied to the evaporator
d) the amount of cold air released from the system
Answer: b
Clarification: In solar vapour compression cycle, efficiency of Rankine Cycle increases with increase in temperature of heat exchanger. It does not depend on the amount of heat supplied to the evaporator and the amount of cold air released.
11. Efficiency of solar collector decreases with ______
a) decrease in temperature of heat exchanger
b) increase in temperature of sun
c) increase in temperature
d) the amount of cold air given to the system
Answer: c
Clarification: Efficiency of solar collector decreases with increase in temperature. This is because as the temperature of the working fluid increases, the difference between its maximum heating temperature and the current running temperature decreases. This decreases the ability to hold more heat.
12. Absorption refrigeration uses _______ mechanical power input as compared to vapour compression refrigeration.
a) greater
b) the same
c) the same working fluid as
d) negligible
Answer: d
Clarification: Absorption refrigeration uses negligible mechanical power input as compared to vapour compression refrigeration. Ammonia is used as working fluid in absorption refrigeration.
13. How is pressurization achieved in absorber refrigeration?
a) By dissolving refrigerant in absorbent in the absorber section
b) By dissolving refrigerant in absorbent in the evaporation section
c) By evaporating refrigerant from absorbent in the absorber section
d) By evaporating refrigerant in absorbent in the evaporation section
Answer: a
Clarification: In absorber refrigeration, pressurisation is achieved by dissolving refrigerant in absorbent in the absorber section. Evaporator section is used to evaporate the refrigerant.
14. In absorber refrigeration, the solution of working fluid (ammonia) is pumped to a low pressure with a big pump.
a) True
b) False
Answer: b
Clarification: In absorber refrigeration, the solution of working fluid (ammonia) is pumped to a high pressure. This is done with the help of a small/ordinary pump.
15. Vapour compression refrigeration system is less complex than absorber refrigeration system.
a) True
b) False
Answer: a
Clarification: Vapour compression refrigeration system is less complex than absorber refrigeration system. This is because the absorber refrigeration system uses thermal compression and not mechanical compression.
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