Vapour Absorption vs Vapour Compression Systems
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Questions and Answers

What is the primary method to provide mechanical cooling?

  • Vapour compression refrigeration (correct)
  • Air conditioning fans
  • Vapour absorption refrigeration
  • Thermal insulation

    • In compression refrigeration cycles, what advantage do highly compressed fluids at one temperature have?

  • They evaporate immediately when expanded
  • They get warmer when expanded
  • They tend to get colder when expanded (correct)
  • They stay at the same temperature when expanded

    • What advantage do vapour-compression refrigeration cycles have regarding thermal energy?

  • They require minimal thermal energy
  • They exploit the large thermal energy required to change a liquid to a vapour (correct)
  • They have high thermal conductivity
  • They don't rely on thermal energy

    • What is the benefit of the isothermal nature of vaporization in vapour compression refrigeration?

    <p>It allows extraction of heat without raising the working fluid temperature to that of what is being cooled</p> Signup and view all the answers

    What is the main challenge in refrigeration and air conditioning systems?

    <p>Removing heat from a low temperature source and dumping it at a higher temperature sink</p> Signup and view all the answers

    Why do compression refrigeration cycles take advantage of highly compressed fluids?

    <p>To get colder when allowed to expand</p> Signup and view all the answers

    What did Carrier present in an ASME meeting?

    <p>Rational Psychrometric Formulae</p> Signup and view all the answers

    When did air conditioning for comfort begin in motion-picture theatres?

    <p>1920 in Chicago</p> Signup and view all the answers

    What is the working substance under study in air conditioning?

    <p>Moist air</p> Signup and view all the answers

    Is moist air considered a pure substance?

    <p>Only when moisture does not condense or evaporate</p> Signup and view all the answers

    Which gases make up the fixed part of moist air?

    <p>Oxygen and nitrogen</p> Signup and view all the answers

    In what kind of laws can perfect gas laws be applied?

    <p>To both dry air and water vapor</p> Signup and view all the answers

    What are the four basic components of all vapor compression systems?

    <p>Evaporator, Condenser, Compressor, Expansion Valve</p> Signup and view all the answers

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

    <p>Control the flow of condensed refrigerant back into the evaporator</p> Signup and view all the answers

    Why is the Carnot vapor compression cycle not suited for practical refrigeration systems?

    <p>It involves wet compression of the refrigeration vapor</p> Signup and view all the answers

    What is the purpose of a throttle valve in a vapor compression system?

    <p>Throttle the refrigerant from high to low pressure regions</p> Signup and view all the answers

    Why is wet compression undesirable in a refrigeration system?

    <p>It requires two different fluid phases to be compressed</p> Signup and view all the answers

    Which component is responsible for raising the pressure of the refrigerant in a vapor compression system?

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

    What component controls the flow of condensed refrigerant back into the evaporator?

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

    Why is an isentropic expansion preferred over throttling in a vapor compression cycle?

    <p>Isentropic expansion produces more work output</p> Signup and view all the answers

    What happens during wet compression in a vapor compression cycle?

    <p>The liquid droplets react with the lubricant in the compressor</p> Signup and view all the answers

    In which path of the Carnot vapor compression cycle does dry compression occur?

    <p>1-2-3-4</p> Signup and view all the answers

    What is the main reason the Carnot vapor refrigeration cycle is not suitable for use in refrigeration systems?

    <p>Low efficiency</p> Signup and view all the answers

    In a vapor compression refrigeration cycle, what process is used to achieve the desired expansion from state 4 to state 5?

    <p>Throttling in an expansion valve</p> Signup and view all the answers

    How does a vapor absorption system differ from a vapor compression system?

    <p>Use of absorbent and generator</p> Signup and view all the answers

    What is the function of the absorbent in the absorber of a vapor absorption system?

    <p>Drawing (or sucking) the refrigerant vapour</p> Signup and view all the answers

    In a lithium bromide absorption system, what is used as the absorbent?

    <p>Lithium bromide</p> Signup and view all the answers

    What function does the generator perform in a vapor absorption system?

    <p>Heating the absorbent</p> Signup and view all the answers

    Who is known as the 'Father of Air Conditioning'?

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

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