Introduction to Refrigeration
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Questions and Answers

What does refrigeration aim to achieve?

  • Increase the temperature of the space
  • Extract heat from the surroundings and reduce its humidity
  • Cool the surrounding atmosphere
  • Maintain the temperature of the space lower than the surroundings (correct)

    • Which of the following is NOT mentioned as an important environment variable in the text?

  • Pressure
  • Temperature
  • Humidity
  • Color (correct)

    • Why is adaptation to unpredictable variations in the environment not possible?

  • Living beings do not have the required technology to adapt
  • The environment variables keep changing frequently (correct)
  • Living beings find it difficult to predict changes
  • The living beings are not capable of adapting

    • What is essential for living beings and non-living subjects in order to perform better and have longer lives according to the text?

    <p>Control of the environment (D)</p> Signup and view all the answers

    What is the literal meaning of refrigeration?

    <p>Cooling down confinement relative to surroundings (C)</p> Signup and view all the answers

    What does the mechanical device do in refrigeration?

    <p>Extracts heat from the space that needs to be cooled (B)</p> Signup and view all the answers

    What is the main purpose of refrigeration as described in the text?

    <p>Removing heat from unwanted spaces (C)</p> Signup and view all the answers

    Why does the text mention the example of spoilage of food products to explain the concept of refrigeration?

    <p>To illustrate the effect of temperature on food spoilage (A)</p> Signup and view all the answers

    In which scenario is heat pumped inside a space as mentioned in the text?

    <p>Refrigeration in a car during winter (D)</p> Signup and view all the answers

    What role does a refrigerator play in preserving perishable food products?

    <p>Removing unwanted heat from the food products (D)</p> Signup and view all the answers

    Why does the text mention that volume matters when discussing refrigeration?

    <p>To show the impact of volume difference on temperature change (C)</p> Signup and view all the answers

    How does the process of refrigeration affect molecular motion in perishable food products?

    <p>Slows down molecular motion (D)</p> Signup and view all the answers

    What is the purpose of a heat pump in the context of refrigeration?

    <p>Transfer heat from lower temperature spaces to higher temperature environments (B)</p> Signup and view all the answers

    Which component plays a crucial role in air conditioning according to the text?

    <p>Refrigeration unit controls (B)</p> Signup and view all the answers

    Why is heat removal crucial in refrigeration processes?

    <p>To preserve perishable items better (C)</p> Signup and view all the answers

    What is the primary function of a refrigerator compared to its surrounding environment?

    <p>Minimize changes in room temperature (C)</p> Signup and view all the answers

    What is air conditioning defined as?

    <p>The process of controlling temperature, humidity, cleanliness, and air motion simultaneously. (C)</p> Signup and view all the answers

    In what way does summer air conditioning differ from winter air conditioning?

    <p>Summer air conditioning cools the space and removes extra moisture while winter air conditioning heats the space and adds moisture. (B)</p> Signup and view all the answers

    Why is it important to control both temperature and humidity for human comfort?

    <p>Because temperature alone cannot ensure comfort. (C)</p> Signup and view all the answers

    Which of these is a key component of industrial air conditioning?

    <p>Air conditioning of computer rooms (B)</p> Signup and view all the answers

    What is the primary difference between comfort air conditioning and industrial air conditioning?

    <p>Industrial air conditioning is concerned with industrial spaces like computer rooms. (C)</p> Signup and view all the answers

    Why is it necessary to consider air purity in the context of air conditioning?

    <p>To maintain comfort levels for human beings (D)</p> Signup and view all the answers

    What is the purpose of a dehumidifier in the context of summer air conditioning?

    <p><strong>Remove</strong> extra moisture from the space (B)</p> Signup and view all the answers

    Considering all components, which is essential to achieve comfort in the context of air conditioning?

    <p><strong>Temperature</strong>, <strong>humidity</strong>, <strong>cleanliness</strong>, and <strong>air motion</strong> control (C)</p> Signup and view all the answers

    What distinguishes a refrigeration system in summer air conditioning from a heat pump in winter air conditioning?

    <p>A refrigeration system cools the space while a heat pump heats the space. (C)</p> Signup and view all the answers

    In what context is control of air pressure included under air conditioning?

    <p>As part of both comfort and industrial air conditioning systems (C)</p> Signup and view all the answers

    Which historical figure obtained the first American patent for a cold air machine to produce ice?

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

    Who was known for developing the first British patent related to refrigeration in 1790?

    <p>Thomas Hariss (C)</p> Signup and view all the answers

    In the 19th century, what was developed to replace natural ice by artificial ice producing machines?

    <p>Refrigeration systems (B)</p> Signup and view all the answers

    Who used sulfuric ether instead of air or ether in a refrigeration machine around 1860?

    <p>Dr. James Harrison (B)</p> Signup and view all the answers

    What was the purpose of Dr. John Gorrie's cold air machine that produced ice?

    <p>To cure people suffering from high fever (D)</p> Signup and view all the answers

    What type of compressor did Dr. Alexander Kirk use in his cold air machine similar to that of Dr. Gorrie?

    <p>Reciprocating compressor driven by steam engine (C)</p> Signup and view all the answers

    What method was used to produce ice artificially due to the limited availability of natural ice?

    <p>Dissolving salt in water (B)</p> Signup and view all the answers

    In which century was there remarkable development of refrigeration systems to replace natural ice with artificial ice producing machines?

    <p>19th century (A)</p> Signup and view all the answers

    Which pioneer used ammonia and water in a vapor-absorption refrigeration system during the civil war?

    <p>Dr. Ferdinand Carre (A)</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 (C)</p> Signup and view all the answers

    Why is superheating of the suction vapour advisable in refrigeration systems?

    <p>To ensure complete vaporization of the liquid before it enters the compressor (C)</p> Signup and view all the answers

    What does superheating the suction vapour help achieve with some refrigerants like Freon 12?

    <p>Maximizing coefficient of performance (COP) (D)</p> Signup and view all the answers

    How does an increase in condenser pressure affect refrigerating capacity and power consumption per ton of refrigeration?

    <p>Effect is less severe compared to a decrease in evaporator pressure (C)</p> Signup and view all the answers

    What role does the degree of superheat play in most refrigeration and air-conditioning systems?

    <p>Actuating and modulating the capacity of the expansion valve (B)</p> Signup and view all the answers

    What effect does superheating of the vapour have on the specific volume of suction vapour?

    <p>Increases the specific volume (A)</p> Signup and view all the answers

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

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

    Which industry began to stagnate due to the use of NH3 and SO2 as refrigerants before the development of new refrigerants?

    <p>Refrigeration industry (B)</p> Signup and view all the answers

    What is one advantage of chlorfluor carbons over NH3 and SO2 as refrigerants?

    <p>Chlorfluor carbons are non-toxic substances (A)</p> Signup and view all the answers

    What is the primary focus of industrial air conditioning?

    <p>Making workers comfortable in harsh environments (A)</p> Signup and view all the answers

    What specific conditions does comfort air conditioning aim to control?

    <p>Management of temperature, humidity, cleanliness, and air distribution (A)</p> Signup and view all the answers

    What does spot heating aim to achieve?

    <p>Providing warmth to a specific area where a worker is located (D)</p> Signup and view all the answers

    What is the purpose of directing a stream of cool air onto occupied areas?

    <p>To keep specific areas tolerable for workers (B)</p> Signup and view all the answers

    'Comfort air conditioning' aims to ________.

    <p><em>Provide comfort temperature and humidity for occupants</em> (A)</p> Signup and view all the answers

    What is the primary purpose of air conditioning in the computer rooms?

    <p>To prevent localized high temperatures and maintain relative humidity for comfort conditions. (C)</p> Signup and view all the answers

    What is the major contributor to the cooling load in planes, trains, ships, and buses?

    <p>Heat from solar radiation. (A)</p> Signup and view all the answers

    What problem arises in printing processes if humidity is not properly maintained?

    <p>Static electricity issues. (C)</p> Signup and view all the answers

    What aspect of refrigeration is important for extending the storage life of perishable foods like meats and fish?

    <p>Using refrigeration to extend storage life. (A)</p> Signup and view all the answers

    Which industry is highlighted as a large user of refrigeration and air conditioning due to temperature sensitivity of materials?

    <p>Photographic products industry. (C)</p> Signup and view all the answers

    What role does air conditioning play in precision metal parts manufacturing?

    <p>To keep the temperature uniform, prevent rust, and minimize dust. (C)</p> Signup and view all the answers

    What is the significance of maintaining a relative humidity of about 65% in computer rooms?

    <p>For comfort condition. (B)</p> Signup and view all the answers

    What raw materials are particularly sensitive to changes in humidity and temperature?

    <p>Photographic materials. (B)</p> Signup and view all the answers

    What is the standard unit of refrigeration equivalent to?

    <p>The rate of heat transfer needed to produce 1 ton (2000 lbs) of ice at 32°F from water at 32°F in one day. (C)</p> Signup and view all the answers

    What is the primary function of a vapour compression cycle in refrigeration systems?

    <p>To circulate a refrigerant alternately condensing and evaporating throughout the system. (B)</p> Signup and view all the answers

    What is the term for the heat absorbed or extracted by the liquid-vapour refrigerant during evaporation per kg of refrigerant?

    <p>Refrigerating effect (C)</p> Signup and view all the answers

    What decreases due to the frictional resistance of flow of the refrigerant in the refrigeration system?

    <p>Suction pressure (C)</p> Signup and view all the answers

    In a refrigeration system, what does a decrease in suction pressure lead to?

    <p>Decreased refrigerating capacity (C)</p> Signup and view all the answers

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

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

    What happens to the net effect on the Coefficient of Performance when the suction pressure decreases?

    <p>It decreases (A)</p> Signup and view all the answers

    How does a decrease in evaporator temperature affect the compressor work in a refrigeration system?

    <p>It increases compressor work due to reduced pressure ratio (A)</p> Signup and view all the answers

    What results from an increase in condenser pressure in a refrigeration system?

    <p>Decreased refrigerating capacity and increased power consumption (B)</p> Signup and view all the answers

    How does a decrease in evaporator temperature affect the specific volume of suction vapour in a reciprocating compressor?

    <p>It increases (A)</p> Signup and view all the answers

    What is affected when there is a drop in evaporator pressure corresponding to a decrease in evaporator temperature?

    <p>Volumetric efficiency only. (C)</p> Signup and view all the answers

    What happens when there is an increase in discharge pressure due to frictional resistance of flow of refrigerant?

    <p>Increase in refrigeration cost. (D)</p> Signup and view all the answers

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

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

    What happens to the liquid refrigerant as it passes through the expansion valve in a vapor compression refrigeration system?

    <p>Some of it evaporates while its pressure and temperature are reduced (D)</p> Signup and view all the answers

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

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

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

    <p>To evaporate the liquid-vapor refrigerant at low pressure and temperature (C)</p> Signup and view all the answers

    What is the purpose of the compressor in a vapor compression refrigeration system?

    <p>To compress the low pressure and temperature vapor refrigerant (C)</p> Signup and view all the answers

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

    <p>It is cooled and condensed into liquid form (D)</p> Signup and view all the answers

    What happens during the throttling process through the expansion valve in a vapor compression refrigeration system?

    <p>No change occurs in the liquid refrigerant (A)</p> Signup and view all the answers

    Which part of a vapor compression refrigeration system stores the condensed liquid refrigerant?

    <p>Receiver (D)</p> Signup and view all the answers

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