Basic Air Conditioning Fundamentals
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Questions and Answers

What is defined as the amount of heat needed to raise one kilogram of water by one degree Celsius?

  • Latent heat
  • BTU
  • Kilo-Calorie (correct)
  • Sensible heat

    • What type of heat results in a rise of temperature when applied to a body?

  • Enthalpy
  • Sensible heat (correct)
  • Latent heat
  • Critical heat

    • What happens to a gas when it is above its critical temperature?

  • It loses its enthalpy
  • It condenses into a liquid without any pressure change
  • It cannot be liquefied by increasing the pressure (correct)
  • It can be easily liquefied by cooling

    • Which of the following represents the latent heat of evaporation of water?

    <p>Both B and C</p> Signup and view all the answers

    How does pressure affect the boiling point of water?

    <p>Increased pressure raises the boiling point</p> Signup and view all the answers

    What is the term for the total heat content in a vapor?

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

    What is the latent heat of fusion of ice in terms of BTUs per pound?

    <p>144 BTUs/lb</p> Signup and view all the answers

    Which of the following measurements is equivalent to 1 Kilo-Calorie?

    <p>3.97 BTU</p> Signup and view all the answers

    What is the primary characteristic of latent heat?

    <p>It changes the state of a substance without changing its temperature</p> Signup and view all the answers

    At what temperature does water boil under atmospheric pressure?

    <p>100°C</p> Signup and view all the answers

    What is the primary measurement associated with Psychrometry?

    <p>Moisture Content in Air</p> Signup and view all the answers

    What does the Dry Bulb Temperature (DBT) measure?

    <p>Temperature of air measured by an ordinary thermometer</p> Signup and view all the answers

    What effect does the Wet Bulb Temperature (WBT) measurement have on the mercury column in the thermometer?

    <p>It drops as moisture evaporates</p> Signup and view all the answers

    How does the difference between DBT and WBT change as air is cooled?

    <p>It decreases until reaching zero at saturation</p> Signup and view all the answers

    At what point are Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) equal?

    <p>At complete saturation of air</p> Signup and view all the answers

    What is Dew Point Temperature (DPT)?

    <p>The temperature at which moisture starts condensing</p> Signup and view all the answers

    What does Effective Temperature (ET) combine to determine?

    <p>Temperature, humidity, and air movement effects on comfort</p> Signup and view all the answers

    What happens to moisture in the air when it is cooled further after reaching saturation?

    <p>It is expelled from air and condenses</p> Signup and view all the answers

    What occurs as air is heated regarding DBT and WBT?

    <p>DBT increases and WBT increases at a slower rate</p> Signup and view all the answers

    What is the relationship between relative humidity and the difference between DBT and WBT?

    <p>An increase in humidity decreases this difference</p> Signup and view all the answers

    What is the unit conversion factor between Kilo-Calorie and BTU?

    <p>1 Kcal = 3.97 BTU</p> Signup and view all the answers

    Which type of heat is responsible for changing the state of a substance without altering its temperature?

    <p>Latent heat</p> Signup and view all the answers

    What happens to the boiling point of water if the pressure is lowered below atmospheric levels?

    <p>The boiling point decreases</p> Signup and view all the answers

    At what stage can a gas be liquefied solely by increasing the pressure without lowering its temperature?

    <p>Below its critical temperature</p> Signup and view all the answers

    What is the latent heat of fusion of ice in Kilo-Calorie per kilogram?

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

    What is the relationship between enthalpy and its components?

    <p>Enthalpy is the sum of sensible and latent heat</p> Signup and view all the answers

    What is the latent heat of evaporation of water in Kilo-Calorie per kilogram?

    <p>538.75 k.cal/kg</p> Signup and view all the answers

    Which property is defined as the total heat content in a vapor?

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

    What condition must be met for water to boil at a temperature lower than 100°C?

    <p>Decreased pressure or vacuum</p> Signup and view all the answers

    How does sensible heat differ from latent heat?

    <p>Sensible heat changes temperature; latent heat changes state.</p> Signup and view all the answers

    What is the purpose of a Wet Bulb Temperature (WBT) measurement?

    <p>To determine the moisture content of air</p> Signup and view all the answers

    How does the difference between Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) change with an increase in humidity?

    <p>The difference decreases</p> Signup and view all the answers

    What does a Dew Point Temperature (DPT) of 100% relative humidity indicate?

    <p>Complete condensation of moisture</p> Signup and view all the answers

    What is Effective Temperature (ET) primarily used to assess?

    <p>Comfort levels in varying environmental conditions</p> Signup and view all the answers

    What occurs to moisture in the air as the temperature continues to drop after reaching saturation?

    <p>Moisture condenses and is expelled from the air</p> Signup and view all the answers

    What defines the term Dry Bulb Temperature (DBT)?

    <p>The temperature of air measured by a conventional thermometer</p> Signup and view all the answers

    In psychrometry, what is the significance of the principle of latent heat during the Wet Bulb Temperature measurement?

    <p>It results in a physical cooling effect on the thermometer.</p> Signup and view all the answers

    What happens to Wet Bulb Temperature as the air is heated?

    <p>It increases at a slower rate than DBT</p> Signup and view all the answers

    Which of the following statements best reflects the properties of specific refrigerants compared to water?

    <p>Their boiling points are generally lower than that of water.</p> Signup and view all the answers

    What describes the behavior of water boiling at an increased pressure?

    <p>It boils at a higher temperature than atmospheric pressure.</p> Signup and view all the answers

    Which statement best describes sensible heat?

    <p>It can be measured by a thermometer.</p> Signup and view all the answers

    What is the relationship between pressure and gas liquefaction at temperatures below critical points?

    <p>Gas can be liquefied by lowering temperature.</p> Signup and view all the answers

    What is the equivalent measurement of 1 Kilo-Calorie in BTUs?

    <p>3.97 BTU</p> Signup and view all the answers

    What happens to the boiling point of a liquid in a vacuum?

    <p>It decreases and can boil at a lower temperature.</p> Signup and view all the answers

    What is critical temperature in relation to gas states?

    <p>It's the temperature above which a gas can be liquefied.</p> Signup and view all the answers

    Which of the following defines enthalpy?

    <p>The total heat content of a vapor.</p> Signup and view all the answers

    What is the significance of Wet Bulb Temperature (WBT) in relation to air humidity?

    <p>It indicates a lower temperature at higher humidity.</p> Signup and view all the answers

    At what condition do the Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) become equal?

    <p>When the air is saturated with moisture.</p> Signup and view all the answers

    What happens as the pressure is decreased on a boiling liquid?

    <p>The boiling point decreases.</p> Signup and view all the answers

    What occurs when air is cooled further after reaching saturation?

    <p>Additional moisture condenses out of the air.</p> Signup and view all the answers

    What is the definition of Dew Point Temperature (DPT)?

    <p>The temperature where moisture starts condensing in the air.</p> Signup and view all the answers

    Effective Temperature (ET) is defined as:

    <p>An index combining temperature, humidity, and air movement.</p> Signup and view all the answers

    What happens to the Wet Bulb Temperature (WBT) as air is heated?

    <p>WBT increases, but slower than DBT.</p> Signup and view all the answers

    Dry Bulb Temperature (DBT) is primarily measured with:

    <p>An ordinary thermometer.</p> Signup and view all the answers

    What device or method measures the amount of moisture content in the air?

    <p>Psychrometry.</p> Signup and view all the answers

    Which condition indicates 100% relative humidity?

    <p>Dew Point Temperature (DPT).</p> Signup and view all the answers

    The difference between Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) indicates:

    <p>Relative humidity levels.</p> Signup and view all the answers

    What happens to the Wet Bulb Temperature (WBT) as humidity increases?

    <p>It increases but at a slower rate compared to Dry Bulb Temperature</p> Signup and view all the answers

    What is indicated by the fact that Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) are equal?

    <p>The air is fully saturated with water vapor</p> Signup and view all the answers

    Which term refers to the temperature at which moisture in the air begins to condense?

    <p>Dew Point Temperature (DPT)</p> Signup and view all the answers

    In the context of psychrometry, what does Effective Temperature (ET) combine?

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

    What happens to the difference between DBT and WBT as air is cooled?

    <p>It decreases until it reaches zero at saturation</p> Signup and view all the answers

    What key factor does Wet Bulb Temperature (WBT) depend on during measurement?

    <p>The relative humidity of the surrounding air</p> Signup and view all the answers

    Which statement best identifies the relationship between DBT, WBT, and humidity?

    <p>Higher humidity results in a smaller difference between DBT and WBT</p> Signup and view all the answers

    What does a higher Effective Temperature (ET) indicate in relation to human comfort?

    <p>Increased comfort levels in a noise-free environment</p> Signup and view all the answers

    Which factor influences the boiling point of water when changed?

    <p>The atmospheric pressure exerted on it.</p> Signup and view all the answers

    What distinguishes latent heat from sensible heat?

    <p>Latent heat does not result in a temperature change.</p> Signup and view all the answers

    What is the significance of enthalpy in thermodynamics?

    <p>It represents the total energy of a system including work done.</p> Signup and view all the answers

    What amount of heat is required to raise the temperature of one kilogram of water by one degree Celsius?

    <p>1 Kilo-Calorie</p> Signup and view all the answers

    What occurs when pressure is applied to a boiling liquid?

    <p>The boiling point will generally increase.</p> Signup and view all the answers

    How does the transformation of ice to water illustrate latent heat?

    <p>It absorbs heat without a temperature change.</p> Signup and view all the answers

    Which unit of measurement is equivalent to 1 Kilo-Calorie?

    <p>3.97 BTUs</p> Signup and view all the answers

    What is the primary factor that determines whether a gas can be liquefied when above its critical temperature?

    <p>The increase in pressure applied to the gas</p> Signup and view all the answers

    Which statement best describes the change in boiling point of water under varying pressure conditions?

    <p>Boiling point increases with increased pressure and decreases with lowered pressure</p> Signup and view all the answers

    What is the significance of enthalpy in thermodynamic processes?

    <p>It is the total sum of all forms of heat in a system</p> Signup and view all the answers

    What happens to the latent heat of evaporation when the temperature of water increases?

    <p>It may increase due to enhanced molecular activity</p> Signup and view all the answers

    Which of these statements about sensible heat is true?

    <p>It can be measured directly using a thermometer</p> Signup and view all the answers

    Under which condition can water boil at a temperature below 100°C?

    <p>When a vacuum exists above its surface</p> Signup and view all the answers

    Which measurement indicates the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit?

    <p>One BTU</p> Signup and view all the answers

    What is the implication of critical temperature for gas behavior?

    <p>It indicates the temperature above which a gas cannot be liquefied regardless of pressure</p> Signup and view all the answers

    What is the primary purpose of measuring Wet Bulb Temperature (WBT)?

    <p>To evaluate the cooling effect of evaporation</p> Signup and view all the answers

    How does the difference between Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) change with increasing humidity?

    <p>The difference decreases until it reaches zero at saturation</p> Signup and view all the answers

    At what Dew Point Temperature (DPT) is relative humidity considered to be 100%?

    <p>When air is saturated with vapor</p> Signup and view all the answers

    What does Effective Temperature (ET) combine to assess human comfort?

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

    What occurs when air is cooled further after reaching its saturation point?

    <p>Moisture in the air condenses and is expelled</p> Signup and view all the answers

    Which property defines the concept of Dry Bulb Temperature (DBT)?

    <p>The temperature of air without considering humidity</p> Signup and view all the answers

    In psychrometry, how is the relationship between Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) described when air is heated?

    <p>DBT increases faster than WBT, widening the difference</p> Signup and view all the answers

    What is the significance of measuring Wet Bulb Temperature (WBT) in relation to air humidity?

    <p>It assesses the moisture capacity of the air</p> Signup and view all the answers

    Study Notes

    Basic Air Conditioning Fundamentals

    • Kilo-calorie: The amount of heat needed to raise the temperature of one kilogram of water by one degree Celsius.
    • BTU: The amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit.
    • 1 Kilo-calorie = 3.97 BTU
    • Sensible Heat: Heat that causes a rise in temperature when applied to a body. It can be measured by a thermometer.
    • Latent Heat: Heat that changes the state of a substance (solid, liquid, or gas) without changing its temperature.
    • Latent Heat of Fusion of Ice: The amount of heat needed to melt ice without changing its temperature.
    • Latent Heat of Evaporation of Water: The amount of heat needed to evaporate water without changing its temperature.
    • Enthalpy: The total heat content of a vapor, calculated as the sum of sensible heat and latent heat.
    • Critical Temperature (Tc): The temperature above which a gas cannot be liquefied, no matter how much pressure is applied.
    • Critical Temperature (Tc): The specific temperature for a given liquid or gas, above which the gas cannot be liquefied.

    Temperature and Pressure Relationship

    • Water boils at 100°C when the pressure is atmospheric.
    • Increasing pressure on water increases its boiling point.
    • Decreasing pressure on water decreases its boiling point.
    • Boiling water doesn't always have to be hot. Low temperatures are possible with vacuum.
    • Refrigerants have similar properties to water in terms of boiling points.

    Psychrometrics

    • Psychrometrics: The measurement of moisture content in air.
    • Dry Bulb Temperature (DBT): The temperature of air as measured by a standard thermometer.
    • Wet Bulb Temperature (WBT): The temperature of air measured using a thermometer with a wet cotton sleeve. This measures temperature after water evaporates, pulling heat from the surrounding air.
    • Dew Point Temperature (DPT): The temperature at which air becomes saturated with water vapor, and moisture condenses. Relative humidity is 100% at this point.
    • Effective Temperature (ET): A combined measure of temperature, humidity, and air movement that relates to human comfort. It's an arbitrary index.

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    Air Conditioning Fundamentals PDF

    Description

    This quiz covers the essential concepts of air conditioning, including the definitions of kilo-calories, BTUs, sensible heat, latent heat, and enhtalpy. Understand the science behind thermal energy and how it relates to air conditioning systems. Test your knowledge on these fundamental principles of thermodynamics.

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