74 Questions
What is one of the functions of an air conditioning plant in a summer system?
Acting as a heat sink
Which media is NOT mentioned in the text for transferring energy in an air conditioning system?
Oil
What is the main purpose of a thermal distribution system in an air conditioning setup?
To circulate media
What factor is NOT mentioned as a consideration for selecting an air conditioning system?
Energy efficiency
In a winter air conditioning system, what role does the air conditioning plant play?
Acting as a heat source
Apart from energy, what else needs to be extracted from the conditioned space in the summer according to the text?
Humidity
What type of air conditioning system uses air as the media to transport energy from the conditioned space to the A/C plant?
All air systems
In the context of air conditioning systems, what is a 'single duct system' known for?
Supplying either cooling or heating through the same duct
What is the primary function of a humidistat in an air conditioning system?
Measuring humidity ratio and controlling humidifier output
How are dual duct systems different from single duct systems in air conditioning?
They use two separate supply ducts
What is the role of a thermostat in a single duct system?
Controlling supply air temperature based on conditioned space temperature
Why are single zone systems called 'single zone'?
They control temperature at only one point in the system
In single duct systems, what is retained within the conditioned space after leaving?
Recirculated part of return air
What characteristic distinguishes dual duct variable volume systems from dual duct constant volume systems?
'Variable volume' refers to adjustable airflow rates
What is a common feature of constant volume, single zone systems in air conditioning?
'Constant volume' refers to fixed supply airflow rates
What distinguishes unitary refrigerant based systems from other classifications of air conditioning systems?
Employing refrigerant as the fluid medium
What is the purpose of maintaining a minimum amount of outdoor air in the air conditioning system?
To conserve energy by utilizing outdoor air effectively
In all air systems, what temperature range would require 100% outdoor air?
13oC to 24oC
Why might it be difficult to provide air conditioning in high-rise buildings using all air systems?
As a result of space constraints due to the system occupying more space
What type of application is most suitable for all water systems in air conditioning?
Buildings with individual control of multiple zones
In all water systems, what type of energy is transported between the conditioned space and the air conditioning plant?
Water
What classification depends on the number of pipes used in all water systems?
Pipe system classification
Which advantage of all air systems allows for easier changeover from summer to winter?
Simultaneous cooling and heating provision
What could be a challenge in balancing air in all air systems with variable air volume?
Balancing air in large systems
How does using high-quality controls benefit all air systems?
By maintaining room temperature within ± 0.15oC and relative humidity within ± 0.5%
In a 2-pipe system of all water systems, what is the function of the two pipes?
Supply cold/hot water and supply return water
What system consists of two supply pipelines, one for cold water and one for hot water, and two return water pipelines?
4-pipe system
How is the airflow rate controlled in a fan coil unit?
By varying the fan speed
In a convector, how does heat transfer between the coil and surrounding air primarily occur?
Natural convection
What is used for transferring heat in a fan coil unit?
All of the above
What is the purpose of a cleanable or replaceable filter located in a fan coil unit?
To prevent dust accumulation on the cooling coil
How is heat transfer mainly achieved in a radiator?
Radiation
What is the purpose of a pressure relief valve (PRV) in a water line?
To maintain balanced flow rate
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?
Fan coil unit
How is heat transfer between cold/hot water and the conditioned space primarily achieved in the system described?
Combination of conduction, convection, and radiation
What kind of systems are fan coil units used with?
Both 2-pipe and 4-pipe systems
What is the main advantage of variable air volume (VAV) systems over constant volume systems?
Significantly lower power consumption in perimeter zones
In dual duct systems, what is a disadvantage related to space utilization?
Occupy more space due to separate cold and hot air ducts
How do dual duct systems achieve simultaneous cooling and heating in different zones?
By having separate ducts for cold and hot air
What is a common challenge associated with variable air volume (VAV) systems according to the text?
Precise humidity control difficulty
Why is it important to control the outdoor air in all air systems?
For proper ventilation purposes
What is a significant advantage of maintaining a constant flow rate to each zone in dual duct systems?
Maintaining proper indoor air quality
Which system improves energy efficiency by shutting down cooling or heating components based on outside weather conditions?
Dual duct, constant volume system
'Balancing of dampers could be difficult if the airflow rate varies widely' - this statement relates to challenges faced by which type of system?
Variable Air Volume (VAV) systems
'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?
'Dual duct' constant volume systems
What is a key feature of dual duct, variable air volume systems compared to dual duct, constant volume systems?
Reduce air flow rate as zone load drops
What is the term used for the air supplied to the conditioned space from the central plant in an air-water system?
Primary air
Which of the following is a disadvantage of all water systems compared to all air systems?
Difficulty controlling humidity in summer
What is true regarding the use of solar or waste heat for winter heating in buildings with air-water systems?
It is possible due to the small temperature of hot water needed.
Why is draining of condensate water considered a potential problem in air-water systems?
Drainage can cause health problems if water stagnates.
What type of buildings are most suitable for all water systems using fan coil units?
Hotels, apartment buildings, and office buildings
What distinguishes the ventilation provision between all water systems and air-water systems?
Air-water systems utilize primary air for ventilation in the conditioned space.
What is a key feature of room terminals in air-water systems?
They are mainly in the form of induction units.
How does an induction unit work within an air-water system?
By inducing flow of secondary air from the conditioned space
What is the main purpose of chilled water supplied to the conditioned space in an air-water system during summer?
To offset building sensible cooling load only
Why is simultaneous cooling and heating possible with 4-pipe systems?
Due to separate coils for heating and cooling
What is a disadvantage of air-water systems mentioned in the text?
Complicated operation and control due to handling primary air and secondary water
In air-water systems, what can lead to the coils in the conditioned space becoming dirty?
Poor quality of room unit filters
What is a benefit of the absence of latent heat transfer in air-water systems?
Positive impact on odours in the conditioned space
Why is it challenging to shut down the supply of primary air to unoccupied spaces in air-water systems?
Primary air supply is constant to all spaces
Which type of air conditioning system is suitable for exterior buildings with large sensible loads?
Unitary refrigerant based systems
What is a feature of unitary refrigerant based systems as described in the text?
Factory assembled with individual refrigeration systems
Why are unitary refrigerant based systems suitable for various spaces?
Available in varying capacities and types
What distinguishes a split type room air conditioner from a window type room air conditioner?
Location of the expansion valve
'Package units of varying capacity and type' are associated with which kind of air conditioning system?
'Unitary refrigerant based' systems
What is a major difference between room air conditioners and ductable systems with water cooled condensing units?
Location of the condenser fan with motor
What type of control system allows for more precise control of zone humidity in HVAC systems?
Face-and-bypass control
In the context of HVAC systems, what is a disadvantage of using a single duct, multiple zone system with reheat coils?
High energy consumption due to need for cooling and reheating
What type of systems are suitable for spaces with uniform loads or requiring precision control, such as theatres and laboratories?
Single duct, constant volume, multiple zone systems
Why is face-and-bypass control considered to be more expensive compared to coil control in HVAC systems?
It allows for more precise humidity control
Which type of system occupies more physical space but allows for better control of zone humidity in HVAC systems?
Single duct, multiple zone systems with reheat coils
What is a key advantage of using variable air volume (VAV) systems in HVAC applications?
Adjustable air volume supplied to each zone
In the context of HVAC systems, what is a disadvantage of using a single duct, constant volume, multiple zone system?
High physical space requirement
What is a key advantage of using single duct, multiple zone systems with reheat coils in HVAC applications?
Maintains constant supply air amount
Learn about the components and functioning of air conditioning systems, including the supply and extraction of energy like sensible and latent heat. Understand the role of air conditioning plants and thermal distribution systems in maintaining desired conditions within a space.
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