Air Conditioning Systems Introduction
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Questions and Answers

What is one of the functions of an air conditioning plant in a summer system?

  • Circulating media
  • Introducing fresh air
  • Acting as a heat sink (correct)
  • Acting as a heat source

    • Which media is NOT mentioned in the text for transferring energy in an air conditioning system?

  • Air
  • Oil (correct)
  • Refrigerant
  • Water

    • What is the main purpose of a thermal distribution system in an air conditioning setup?

  • To circulate media (correct)
  • To act as a heat sink
  • To introduce fresh air
  • To act as a heat source

    • What factor is NOT mentioned as a consideration for selecting an air conditioning system?

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

    In a winter air conditioning system, what role does the air conditioning plant play?

    <p>Acting as a heat source</p> Signup and view all the answers

    Apart from energy, what else needs to be extracted from the conditioned space in the summer according to the text?

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

    What type of air conditioning system uses air as the media to transport energy from the conditioned space to the A/C plant?

    <p>All air systems</p> Signup and view all the answers

    In the context of air conditioning systems, what is a 'single duct system' known for?

    <p>Supplying either cooling or heating through the same duct</p> Signup and view all the answers

    What is the primary function of a humidistat in an air conditioning system?

    <p>Measuring humidity ratio and controlling humidifier output</p> Signup and view all the answers

    How are dual duct systems different from single duct systems in air conditioning?

    <p>They use two separate supply ducts</p> Signup and view all the answers

    What is the role of a thermostat in a single duct system?

    <p>Controlling supply air temperature based on conditioned space temperature</p> Signup and view all the answers

    Why are single zone systems called 'single zone'?

    <p>They control temperature at only one point in the system</p> Signup and view all the answers

    In single duct systems, what is retained within the conditioned space after leaving?

    <p>Recirculated part of return air</p> Signup and view all the answers

    What characteristic distinguishes dual duct variable volume systems from dual duct constant volume systems?

    <p>'Variable volume' refers to adjustable airflow rates</p> Signup and view all the answers

    What is a common feature of constant volume, single zone systems in air conditioning?

    <p>'Constant volume' refers to fixed supply airflow rates</p> Signup and view all the answers

    What distinguishes unitary refrigerant based systems from other classifications of air conditioning systems?

    <p>Employing refrigerant as the fluid medium</p> Signup and view all the answers

    What is the purpose of maintaining a minimum amount of outdoor air in the air conditioning system?

    <p>To conserve energy by utilizing outdoor air effectively</p> Signup and view all the answers

    In all air systems, what temperature range would require 100% outdoor air?

    <p>13oC to 24oC</p> Signup and view all the answers

    Why might it be difficult to provide air conditioning in high-rise buildings using all air systems?

    <p>As a result of space constraints due to the system occupying more space</p> Signup and view all the answers

    What type of application is most suitable for all water systems in air conditioning?

    <p>Buildings with individual control of multiple zones</p> Signup and view all the answers

    In all water systems, what type of energy is transported between the conditioned space and the air conditioning plant?

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

    What classification depends on the number of pipes used in all water systems?

    <p>Pipe system classification</p> Signup and view all the answers

    Which advantage of all air systems allows for easier changeover from summer to winter?

    <p>Simultaneous cooling and heating provision</p> Signup and view all the answers

    What could be a challenge in balancing air in all air systems with variable air volume?

    <p>Balancing air in large systems</p> Signup and view all the answers

    How does using high-quality controls benefit all air systems?

    <p>By maintaining room temperature within ± 0.15oC and relative humidity within ± 0.5%</p> Signup and view all the answers

    In a 2-pipe system of all water systems, what is the function of the two pipes?

    <p>Supply cold/hot water and supply return water</p> Signup and view all the answers

    What system consists of two supply pipelines, one for cold water and one for hot water, and two return water pipelines?

    <p>4-pipe system</p> Signup and view all the answers

    How is the airflow rate controlled in a fan coil unit?

    <p>By varying the fan speed</p> Signup and view all the answers

    In a convector, how does heat transfer between the coil and surrounding air primarily occur?

    <p>Natural convection</p> Signup and view all the answers

    What is used for transferring heat in a fan coil unit?

    <p>All of the above</p> Signup and view all the answers

    What is the purpose of a cleanable or replaceable filter located in a fan coil unit?

    <p>To prevent dust accumulation on the cooling coil</p> Signup and view all the answers

    How is heat transfer mainly achieved in a radiator?

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

    What is the purpose of a pressure relief valve (PRV) in a water line?

    <p>To maintain balanced flow rate</p> Signup and view all the answers

    What equipment is located inside the conditioned space and consists of a heating and/or cooling coil, a fan, air filter, drain tray and controls?

    <p>Fan coil unit</p> Signup and view all the answers

    How is heat transfer between cold/hot water and the conditioned space primarily achieved in the system described?

    <p>Combination of conduction, convection, and radiation</p> Signup and view all the answers

    What kind of systems are fan coil units used with?

    <p>Both 2-pipe and 4-pipe systems</p> Signup and view all the answers

    What is the main advantage of variable air volume (VAV) systems over constant volume systems?

    <p>Significantly lower power consumption in perimeter zones</p> Signup and view all the answers

    In dual duct systems, what is a disadvantage related to space utilization?

    <p>Occupy more space due to separate cold and hot air ducts</p> Signup and view all the answers

    How do dual duct systems achieve simultaneous cooling and heating in different zones?

    <p>By having separate ducts for cold and hot air</p> Signup and view all the answers

    What is a common challenge associated with variable air volume (VAV) systems according to the text?

    <p>Precise humidity control difficulty</p> Signup and view all the answers

    Why is it important to control the outdoor air in all air systems?

    <p>For proper ventilation purposes</p> Signup and view all the answers

    What is a significant advantage of maintaining a constant flow rate to each zone in dual duct systems?

    <p>Maintaining proper indoor air quality</p> Signup and view all the answers

    Which system improves energy efficiency by shutting down cooling or heating components based on outside weather conditions?

    <p>Dual duct, constant volume system</p> Signup and view all the answers

    'Balancing of dampers could be difficult if the airflow rate varies widely' - this statement relates to challenges faced by which type of system?

    <p>Variable Air Volume (VAV) systems</p> Signup and view all the answers

    'Occupy more space as both cold air and hot air ducts have to be sized to handle all the airflow rate' - this statement refers to which type of system?

    <p>'Dual duct' constant volume systems</p> Signup and view all the answers

    What is a key feature of dual duct, variable air volume systems compared to dual duct, constant volume systems?

    <p>Reduce air flow rate as zone load drops</p> Signup and view all the answers

    What is the term used for the air supplied to the conditioned space from the central plant in an air-water system?

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

    Which of the following is a disadvantage of all water systems compared to all air systems?

    <p>Difficulty controlling humidity in summer</p> Signup and view all the answers

    What is true regarding the use of solar or waste heat for winter heating in buildings with air-water systems?

    <p>It is possible due to the small temperature of hot water needed.</p> Signup and view all the answers

    Why is draining of condensate water considered a potential problem in air-water systems?

    <p>Drainage can cause health problems if water stagnates.</p> Signup and view all the answers

    What type of buildings are most suitable for all water systems using fan coil units?

    <p>Hotels, apartment buildings, and office buildings</p> Signup and view all the answers

    What distinguishes the ventilation provision between all water systems and air-water systems?

    <p>Air-water systems utilize primary air for ventilation in the conditioned space.</p> Signup and view all the answers

    What is a key feature of room terminals in air-water systems?

    <p>They are mainly in the form of induction units.</p> Signup and view all the answers

    How does an induction unit work within an air-water system?

    <p>By inducing flow of secondary air from the conditioned space</p> Signup and view all the answers

    What is the main purpose of chilled water supplied to the conditioned space in an air-water system during summer?

    <p>To offset building sensible cooling load only</p> Signup and view all the answers

    Why is simultaneous cooling and heating possible with 4-pipe systems?

    <p>Due to separate coils for heating and cooling</p> Signup and view all the answers

    What is a disadvantage of air-water systems mentioned in the text?

    <p>Complicated operation and control due to handling primary air and secondary water</p> Signup and view all the answers

    In air-water systems, what can lead to the coils in the conditioned space becoming dirty?

    <p>Poor quality of room unit filters</p> Signup and view all the answers

    What is a benefit of the absence of latent heat transfer in air-water systems?

    <p>Positive impact on odours in the conditioned space</p> Signup and view all the answers

    Why is it challenging to shut down the supply of primary air to unoccupied spaces in air-water systems?

    <p>Primary air supply is constant to all spaces</p> Signup and view all the answers

    Which type of air conditioning system is suitable for exterior buildings with large sensible loads?

    <p>Unitary refrigerant based systems</p> Signup and view all the answers

    What is a feature of unitary refrigerant based systems as described in the text?

    <p>Factory assembled with individual refrigeration systems</p> Signup and view all the answers

    Why are unitary refrigerant based systems suitable for various spaces?

    <p>Available in varying capacities and types</p> Signup and view all the answers

    What distinguishes a split type room air conditioner from a window type room air conditioner?

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

    'Package units of varying capacity and type' are associated with which kind of air conditioning system?

    <p>'Unitary refrigerant based' systems</p> Signup and view all the answers

    What is a major difference between room air conditioners and ductable systems with water cooled condensing units?

    <p>Location of the condenser fan with motor</p> Signup and view all the answers

    What type of control system allows for more precise control of zone humidity in HVAC systems?

    <p>Face-and-bypass control</p> Signup and view all the answers

    In the context of HVAC systems, what is a disadvantage of using a single duct, multiple zone system with reheat coils?

    <p>High energy consumption due to need for cooling and reheating</p> Signup and view all the answers

    What type of systems are suitable for spaces with uniform loads or requiring precision control, such as theatres and laboratories?

    <p>Single duct, constant volume, multiple zone systems</p> Signup and view all the answers

    Why is face-and-bypass control considered to be more expensive compared to coil control in HVAC systems?

    <p>It allows for more precise humidity control</p> Signup and view all the answers

    Which type of system occupies more physical space but allows for better control of zone humidity in HVAC systems?

    <p>Single duct, multiple zone systems with reheat coils</p> Signup and view all the answers

    What is a key advantage of using variable air volume (VAV) systems in HVAC applications?

    <p>Adjustable air volume supplied to each zone</p> Signup and view all the answers

    In the context of HVAC systems, what is a disadvantage of using a single duct, constant volume, multiple zone system?

    <p>High physical space requirement</p> Signup and view all the answers

    What is a key advantage of using single duct, multiple zone systems with reheat coils in HVAC applications?

    <p>Maintains constant supply air amount</p> Signup and view all the answers

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