Air-Conditioning System Performance Quiz
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Questions and Answers

What is the refrigerating effect per Kg of ice when it melts at 0°C?

  • 100 K.cal
  • 50 K.cal
  • 80 K.cal (correct)
  • 120 K.cal

    • How is the theoretical Carnot efficiency for a refrigerating machine calculated?

  • T2 / (T1 - T2) (correct)
  • T1 / (T1 - T2)
  • T2 / (T1 + T2)
  • T1 / (T1 + T2)

    • What does the Co-efficient of Performance (C.O.P.) measure in a refrigerating cycle?

  • Efficiency of the compressor only
  • Latent heat of the refrigerant
  • Refrigerating effect per unit heat supplied (correct)
  • Total heat supplied to the system

    • Which of the following factors does NOT directly affect C.O.P. in refrigerating systems?

    <p>Cost of installation</p> Signup and view all the answers

    What does the KW per ton ratio measure in refrigerating systems?

    <p>Efficiency of the refrigerating machine</p> Signup and view all the answers

    What is essential to consider when selecting a refrigerant for better performance?

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

    In the formula for efficiency of a heat engine, 'Efficiencyc = (T1 - T2) / T1', what does T1 represent?

    <p>Condenser temperature</p> Signup and view all the answers

    Which of the following represents the correct relation stated for the efficiency of a refrigerating machine?

    <p>Efficiency = T2 / (T1 - T2)</p> Signup and view all the answers

    What happens to the refrigerating effect if the latent heat of fusion decreases?

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

    Which of the following best describes the role of the compressor in a refrigerating cycle?

    <p>Pumps the refrigerant to high pressure</p> Signup and view all the answers

    Which factor is critical in determining the refrigerating effect of a refrigerant?

    <p>The latent heat of fusion of the refrigerant</p> Signup and view all the answers

    What does a higher C.O.P. indicate about a refrigerating cycle's performance?

    <p>Greater heat absorption relative to energy input</p> Signup and view all the answers

    In the context of efficiency calculations, what do T1 and T2 represent?

    <p>T1 and T2 represent the absolute temperatures of the evaporator and condenser respectively</p> Signup and view all the answers

    How is the theoretical Carnot efficiency for refrigeration calculated?

    <p>By subtracting the evaporator temperature from the absolute temperature of the condenser</p> Signup and view all the answers

    What does the KW per ton ratio help assess in refrigerating systems?

    <p>The actual cooling capacity versus power consumed</p> Signup and view all the answers

    Why is it important to select a refrigerant with a better refrigerating effect?

    <p>It ensures maximum heat removal efficiency at minimal energy cost</p> Signup and view all the answers

    What happens to the efficiency of refrigerating machines if the temperature difference between T1 and T2 is reduced?

    <p>Efficiency decreases because more energy is needed for lower temperatures</p> Signup and view all the answers

    In the formula for C.O.P. of a refrigerating cycle, what does the numerator represent?

    <p>Heat absorbed from the refrigerated space</p> Signup and view all the answers

    What is the relationship between the latent heat of fusion and the refrigerating effect based on the given content?

    <p>Higher latent heat correlates to a greater refrigerating effect</p> Signup and view all the answers

    What key factors impact the net refrigerating effect in air-conditioning systems?

    <p>Refrigerant used, efficiency of components, temperatures of evaporator and condenser</p> Signup and view all the answers

    Which of the following best describes the refrigerating effect?

    <p>It represents the heat absorbed by each kilogram of refrigerant</p> Signup and view all the answers

    In the efficiency equation for a refrigerating machine, what does T2 represent?

    <p>The temperature of the evaporator in absolute terms</p> Signup and view all the answers

    Which scenario reflects an increase in the efficiency of a refrigerating machine?

    <p>Descending T2 while maintaining T1 constant</p> Signup and view all the answers

    What key role does the refrigerant play in the performance of an air-conditioning system?

    <p>It determines the heat exchange capabilities within the system</p> Signup and view all the answers

    How is KW per ton ratio significant in assessing refrigerating machine efficiency?

    <p>It indicates the energy efficiency of the refrigerating process</p> Signup and view all the answers

    What happens to C.O.P. as the efficiency of the refrigerating cycle improves?

    <p>C.O.P. increases with enhanced cycle efficiency</p> Signup and view all the answers

    In terms of selecting a refrigerant, why is a better refrigerating effect important?

    <p>It ensures faster evaporation at lower temperatures.</p> Signup and view all the answers

    Which factor can negatively impact the performance of an air-conditioning system?

    <p>High evaporator temperatures</p> Signup and view all the answers

    What is the refrigerating effect of 1 Kg of ice melting at 0°C?

    <p>80 K.cal</p> Signup and view all the answers

    Which formula represents the theoretical Carnot efficiency for a refrigerating machine?

    <p>$\frac{T2}{T1 - T2}$</p> Signup and view all the answers

    What does the Co-efficient of Performance (C.O.P.) in a refrigerating cycle express?

    <p>The ratio of heat absorbed to equivalent heat supplied to the compressor</p> Signup and view all the answers

    How does a reduction in the temperature difference between T1 and T2 influence the efficiency of refrigerating machines?

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

    Which factor does NOT affect the refrigerating effect in air-conditioning systems?

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

    What is the importance of selecting a refrigerant with a good refrigerating effect?

    <p>It enhances system efficiency and performance</p> Signup and view all the answers

    Which of the following best describes the KW per ton ratio?

    <p>It is a measure of refrigerating machine efficiency under standard conditions</p> Signup and view all the answers

    What happens to the C.O.P. of a refrigerating cycle as its efficiency improves?

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

    What does a higher coefficient of performance (C.O.P.) imply about the refrigerating cycle's efficiency?

    <p>It reflects an increased cooling capacity per unit of energy consumed.</p> Signup and view all the answers

    In the formula for theoretical efficiency of a refrigerating machine, which relation accurately reflects the temperatures involved?

    <p>Efficiencyc = T2 / (T1 - T2)</p> Signup and view all the answers

    Why is it critical to ensure that a refrigerant has a better refrigerating effect?

    <p>It increases the total heat absorbed from the refrigerated space.</p> Signup and view all the answers

    What does the KW per ton ratio primarily assess in an air-conditioning system?

    <p>The relationship between input power and cooling capacity.</p> Signup and view all the answers

    What is the significance of latent heat of fusion in determining the refrigerating effect?

    <p>It defines how much heat is absorbed during a phase change.</p> Signup and view all the answers

    Which of the following best describes the impact of T1 and T2 on efficiency in refrigerating systems?

    <p>Lower T2 values increase efficiency.</p> Signup and view all the answers

    What would be the effect of using a refrigerant with poor refrigerating effect in air-conditioning systems?

    <p>Lower cooling capacity and increased operational costs.</p> Signup and view all the answers

    How does the theoretical Carnot efficiency formula for refrigerating machines relate to actual performance?

    <p>It provides a baseline for expected performance compared to real-world conditions.</p> Signup and view all the answers

    What does the refrigerating effect measure?

    <p>The amount of heat absorbed from the refrigerated space per unit mass of refrigerant</p> Signup and view all the answers

    Which formula represents the theoretical efficiency of a refrigerating machine?

    <p>Efficiencyc = T2 / (T1 - T2)</p> Signup and view all the answers

    What does the Co-efficient of Performance (C.O.P.) compare?

    <p>Heat absorbed from the refrigerated space to the energy input to the compressor</p> Signup and view all the answers

    Which of the following factors is critical for the performance of an air-conditioning system?

    <p>The refrigerating effect of the refrigerant used</p> Signup and view all the answers

    What is the significance of KW per ton ratio in refrigerating systems?

    <p>It measures the energy consumption relative to cooling output.</p> Signup and view all the answers

    When selecting a refrigerant, which characteristic is most essential?

    <p>Refrigerating effect of the refrigerant</p> Signup and view all the answers

    How does the temperature difference between T1 and T2 influence the efficiency of refrigerating machines?

    <p>A larger difference leads to lower efficiency.</p> Signup and view all the answers

    What does a higher C.O.P. indicate about a refrigerating cycle?

    <p>Greater efficiency of the refrigerating cycle</p> Signup and view all the answers

    Study Notes

    Air-Conditioning System Performance

    • Refrigerating effect is the amount of heat absorbed by 1 kg of refrigerant from a refrigerated space. It's measured in terms of latent heat of fusion (e.g., 80 Kcal/kg for melting ice at 0°C).
    • Refrigerating machine efficiency is similar to a reversed heat engine.
    • Carnot efficiency for a heat engine is given by T1/T2 where T1 and T2 are absolute temperatures in Kelvin.
    • Carnot efficiency for a refrigerator is given by T2/T1.

    Coefficient of Performance (COP)

    • COP is a measure of cycle efficiency, expressed as the ratio of heat absorbed from the refrigerated space to the equivalent heat energy supplied to the compressor.
    • COP = Heat absorbed from refrigerated space / Equivalent heat energy supplied to the compressor

    KW per Ton Ratio

    • A measure of refrigerating machine efficiency, calculated as KW per ton based on cooling rate (e.g., K.Cal/hr) and average KW input during a "standard" performance test.

    Energy Efficiency Ratio (EER)

    • EER is a popular efficiency measure for small to medium capacity unitary conditioners.
    • EER is K.Cal per hour per watt (K.Cal/hr-W).
    • Calculated using the formula: EER = K.cal/Hr cooling rate / Watts input.

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    Performance of Air-Conditioning Systems PDF

    Description

    Test your knowledge on the performance metrics of air-conditioning systems, including refrigerating effect, efficiency, and Coefficient of Performance (COP). This quiz covers key concepts such as Carnot efficiency and KW per ton ratio essential for understanding refrigeration systems.

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