Introduction to Refrigeration
78 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of refrigeration and air-conditioning?

  • To adapt to unpredictable variations in the environment
  • To control the environments of living and non-living subjects (correct)
  • To maintain a temperature higher than the surroundings
  • To extract heat from the surroundings for energy conservation

    • Why is adaptation to unpredictable environmental variations not feasible for living and non-living beings?

  • It allows for longer lives of the beings
  • It increases efficiency in performing tasks
  • It is impossible to adapt to unpredictable variations
  • It hinders efficiency and performance (correct)

    • What does refrigeration achieve in terms of temperature relative to its surroundings?

  • Maintains a temperature lower than its surroundings (correct)
  • Controls the humidity levels in its surroundings
  • Maintains the same temperature as its surroundings
  • Maintains a temperature higher than its surroundings

    • Which important environment variables are mentioned in the text as constantly changing?

    <p>Temperature, humidity, pressure, and air motion</p> Signup and view all the answers

    What does refrigeration achieve by extracting heat from the space under consideration?

    <p>Maintains a lower temperature than the surrounding atmosphere</p> Signup and view all the answers

    Why is control of the environment essential for living and non-living beings?

    <p>To provide comforts for better performance and longevity</p> Signup and view all the answers

    What was the working fluid used by Jacob Perkins in his hand-operated refrigeration system?

    <p>Ether</p> Signup and view all the answers

    Who obtained the first American patent for a cold air machine to produce ice?

    <p>Dr. John Gorrie</p> Signup and view all the answers

    In the 19th century, what was developed to replace natural ice?

    <p>Artificial ice producing machines</p> Signup and view all the answers

    What was the purpose of the vapor-absorption refrigeration system developed by Ferdinand Carre?

    <p>To meet the demand for ice during the civil war</p> Signup and view all the answers

    What was the heat source used to separate ammonia vapor in Ferdinand Carre's refrigeration system?

    <p>A burner</p> Signup and view all the answers

    What was the world's first installation of a refrigeration machine used for brewery?

    <p>James Harrison's system</p> Signup and view all the answers

    In which century were large-sized refrigeration machines developed?

    <p>20th century</p> Signup and view all the answers

    Who developed the first two-stage modern compressor in 1915?

    <p>Dr. John Gorrie</p> Signup and view all the answers

    What method was used to keep water outside homes overnight in ancient India and Egypt to produce ice?

    <p>Evaporation in cool, dry air with radiative heat transfer</p> Signup and view all the answers

    Who is credited with obtaining the first British Patent for a refrigeration system in 1790?

    <p>Thomas Hariss and John Long</p> Signup and view all the answers

    What is the precise meaning of air conditioning?

    <p>Controlling temperature, humidity, cleanliness, and air motion</p> Signup and view all the answers

    Why is external power always required in air conditioning systems?

    <p>To pump out or in the heat</p> Signup and view all the answers

    In the winter air conditioning system, what is added to the space being conditioned?

    <p>Extra moisture</p> Signup and view all the answers

    What does comfort air conditioning primarily deal with?

    <p>Residential buildings and offices only</p> Signup and view all the answers

    Which parameter is NOT considered essential for the comfort of human beings in air conditioning?

    <p>Air pressure</p> Signup and view all the answers

    What role does a dehumidifier play in summer air conditioning?

    <p>Removing extra moisture from the space</p> Signup and view all the answers

    Why is air motion considered essential for comfort in air conditioning?

    <p>To distribute conditioned air evenly</p> Signup and view all the answers

    What distinguishes industrial air conditioning from comfort air conditioning?

    <p>Includes control of air pressure</p> Signup and view all the answers

    What is the primary difference between summer and winter air conditioning systems?

    <p>Heating versus cooling the space</p> Signup and view all the answers

    What happens to the humidity levels during rain in Delhi and Kolkata?

    <p>Humidity decreases in Delhi but increases in Kolkata.</p> Signup and view all the answers

    What was the most important development in refrigeration systems after the 1920s?

    <p>Invention of new refrigerants like chlorfluor hydrocarbons</p> Signup and view all the answers

    What was a major advantage of chlorfluor carbons as refrigerants compared to NH3 and SO2?

    <p>Non-toxicity</p> Signup and view all the answers

    Which specialized field of refrigeration involves removing heat from substances in chemical, petroleum, and petrochemical plants?

    <p>Industrial refrigeration</p> Signup and view all the answers

    What are some examples of applications of air conditioning mentioned in the text?

    <p>Treating air to control temperature, humidity, cleanliness, and distribution</p> Signup and view all the answers

    Why is cooling required in buildings even in places where temperatures remain normal?

    <p>To remove heat generated internally by people and equipment</p> Signup and view all the answers

    What is the main purpose of comfort air conditioning in residential and official buildings?

    <p>To maintain comfortable conditions for people</p> Signup and view all the answers

    What role does air conditioning play in hospitals and medical buildings according to the text?

    <p>To maintain humidity levels and cleanliness</p> Signup and view all the answers

    In what way does spot heating differ from spot cooling?

    <p>Spot heating is more practical in cold weather while spot cooling is more effective in hot weather.</p> Signup and view all the answers

    What is the primary function of air conditioning in environmental laboratories?

    <p>To control humidity and cleanliness of air</p> Signup and view all the answers

    What is the purpose of maintaining a high temperature and humidity in one laboratory?

    <p>To study the behavior of animals in tropical climates</p> Signup and view all the answers

    In the printing industries, what problems arise if humidity is not properly maintained?

    <p>Curling or buckling of paper</p> Signup and view all the answers

    Why are textiles sensitive to changes in humidity and temperature?

    <p>To prevent rust formation</p> Signup and view all the answers

    How does air conditioning help in the manufacturing of precision metal parts?

    <p>Maintain uniform temperature to avoid expansion and contraction</p> Signup and view all the answers

    What is a major contributor to the cooling load in vehicles like planes, trains, and ships?

    <p>Heat from solar radiation</p> Signup and view all the answers

    What is the purpose of using a vapour compression cycle in air refrigeration systems?

    <p>To improve the efficiency of cooling systems</p> Signup and view all the answers

    What is the standard unit of refrigeration used?

    <p>Ton refrigeration</p> Signup and view all the answers

    Why do raw photographic materials deteriorate quickly in high humidity and temperatures?

    <p>Because of high humidity and temperatures</p> Signup and view all the answers

    What is the role of air conditioning in computer rooms?

    <p>Control temperature, humidity, and cleanliness of the air</p> Signup and view all the answers

    How does refrigeration help extend storage life for perishable food products?

    <p>By maintaining low temperatures above freezing point</p> Signup and view all the answers

    What is the purpose of the expansion valve in a refrigeration system?

    <p>To allow the liquid refrigerant to pass at a controlled rate after reducing its pressure and temperature</p> Signup and view all the answers

    What is the role of the condenser in a vapor compression refrigeration system?

    <p>To cool and condense the high pressure and temperature vapor refrigerant</p> Signup and view all the answers

    At what stage of the theoretical vapor compression cycle does the liquid refrigerant evaporate in a refrigeration system?

    <p>Expansion process</p> Signup and view all the answers

    What happens to the refrigerant in the condenser of a vapor compression refrigeration system?

    <p>It is cooled and condensed from a high pressure and temperature vapor to liquid</p> Signup and view all the answers

    What is the function of the receiver in a vapor compression refrigeration system?

    <p>To store the condensed liquid refrigerant before supplying it to the evaporator</p> Signup and view all the answers

    During which phase of the vapor compression cycle does no heat absorption or rejection occur by the liquid refrigerant?

    <p>Expansion process</p> Signup and view all the answers

    What happens to the pressure of the vapor refrigerant during isentropic compression in a vapor compression cycle?

    <p>Pressure increases</p> Signup and view all the answers

    How is the condensed liquid refrigerant supplied to the evaporator in a refrigeration system?

    <p>Through the receiver output valve</p> Signup and view all the answers

    What happens to the medium when liquid-vapor refrigerant evaporates in an evaporator?

    <p>The medium absorbs heat from the evaporating refrigerant</p> Signup and view all the answers

    Which part of a vapor compression cycle stores the high pressure and temperature vapor refrigerant before being condensed?

    <p>Receiver</p> Signup and view all the answers

    What is one of the main benefits of superheating the suction vapour in refrigeration systems?

    <p>Ensures complete vaporization of the liquid in the evaporator</p> Signup and view all the answers

    What role does superheating of the suction vapour play in modulating the capacity of the expansion valve?

    <p>Increases the capacity of the expansion valve</p> Signup and view all the answers

    For which refrigerant is the maximum Coefficient of Performance (COP) obtained with superheating of the suction vapour?

    <p>Freon 12</p> Signup and view all the answers

    What is the primary effect of superheating the suction vapour in refrigeration systems in terms of specific volume?

    <p>Increase in specific volume of suction vapour</p> Signup and view all the answers

    Compared to the decrease in evaporator pressure, what is noted about the effect of an increase in condenser pressure on refrigerating capacity and power consumption?

    <p>It is less significant</p> Signup and view all the answers

    What is the equation for the refrigerating effect (RE) during evaporation?

    <p>RE = h1 - hf3</p> Signup and view all the answers

    What does the Coefficient of Performance (C.O.P.) represent in a refrigerating system?

    <p>Ratio of refrigerating effect to work done</p> Signup and view all the answers

    How does a decrease in suction pressure impact the Coefficient of Performance (C.O.P.) of a refrigerating system?

    <p>Decreases the C.O.P.</p> Signup and view all the answers

    What is the net effect of a decrease in suction pressure on the refrigerating capacity of a system?

    <p>Decreases refrigerating capacity</p> Signup and view all the answers

    How does a decrease in evaporator pressure affect the reciprocating compressor's capacity?

    <p>Decreases compressor's capacity</p> Signup and view all the answers

    What is the consequence of a decrease in evaporator temperature on a reciprocating compressor?

    <p>Decreases volumetric efficiency</p> Signup and view all the answers

    How does an increase in condenser pressure affect refrigeration capacity?

    <p>Decreases refrigeration capacity</p> Signup and view all the answers

    What happens to the Coefficient of Performance (C.O.P.) with decreasing evaporator pressure?

    <p>Decreases C.O.P.</p> Signup and view all the answers

    What effect does increasing condenser pressure have on power consumption?

    <p>Increases specific work</p> Signup and view all the answers

    What is the main reason for a decrease in refrigeration capacity due to an increase in condenser pressure?

    <p>Decrease in refrigerating effect</p> Signup and view all the answers

    What is the primary purpose of refrigeration according to the text?

    <p>Cooling down a space where heat is unwanted</p> Signup and view all the answers

    Why does the temperature inside a refrigerator decrease when food products are kept inside?

    <p>Unwanted heat from the food products is removed</p> Signup and view all the answers

    In the context of refrigeration, why do air-conditioned cars have to reject heat to the surroundings?

    <p>To lower the temperature inside the car by removing heat</p> Signup and view all the answers

    What is one of the main reasons for using refrigerators in homes and canteens?

    <p>To slow down bacterial growth in food products</p> Signup and view all the answers

    Why is it necessary for a refrigerator to transfer unwanted heat from food products to the surrounding environment?

    <p>To maintain a lower temperature inside the refrigerator</p> Signup and view all the answers

    What role does a heat pump play in maintaining comfortable temperatures in different seasons inside a car?

    <p>It rejects heat in hot seasons and absorbs heat in cold seasons</p> Signup and view all the answers

    What distinguishes refrigeration from natural heat flow processes according to the text?

    <p>Heat flow in refrigeration is always from high to low temperatures</p> Signup and view all the answers

    How does refrigeration influence the temperatures inside a car during summer?

    <p>By rejecting heat from inside, lowering internal temperature</p> Signup and view all the answers

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser