Aux 2 Unit 10 Air Conditioning Terms Flashcards

Aux 2 Unit 10 Air Conditioning Terms

What role does the air handling unit (AHU) play in an indirect expansion system?

C) It circulates chilled water to absorb heat from the air and distribute cooled air

What state is the refrigerant in when it exits the evaporator of a DX system?

B) Low-pressure vapor

What type of heat exchange occurs in the evaporator of a DX system?

C) Both sensible and latent cooling

What is "absolute humidity" in the context of air conditioning?

A) The mass of water vapor in a unit volume of air

What is a characteristic of a louvered damper in an HVAC system?

B) It has slats that can be adjusted to control the volume of airflow

What is the primary function of the vapour-compression refrigeration cycle?

B) To transfer heat from a low-temperature region to a high-temperature region

What is meant by the term "heating load" in an air conditioning system?

C) The amount of energy required to raise the temperature of a space to a desired level

What is the main function of the expansion valve in a DX system?

B) To control and reduce the pressure and temperature of the refrigerant before it enters the evaporator

What is an advantage of using a DX refrigeration system for air conditioning?

B) Direct cooling with high efficiency and simple design

What is the function of the expansion valve in a vapour-compression refrigeration cycle?

B) To lower the pressure of the refrigerant and regulate its flow

What does "cooling load" refer to in an air conditioning system?

B) The energy required to lower the temperature of a space to a comfortable level

Which setting adjustment helps an air conditioning system reduce humidity while avoiding overcooling?

C) Use the "Dry Mode" setting, if available

What is the physical state of the refrigerant as it exits the evaporator in a vapour-compression refrigeration cycle?

B) Low-pressure vapor

What happens to the refrigerant as it passes through the compressor?

B) Its pressure and temperature increase

What type of movement is associated with the closure of an automatic fire damper?

B) Rapid snap-shut movement to seal the duct

What is "sensible heat" in the context of air conditioning?

A) Heat that changes the temperature of a substance without changing its state

Why is it important to control the relative humidity in an air-conditioned space?

C) To improve comfort and prevent mold growth

Which of the following is a type of damper used to control airflow in an air conditioning system?

B) Butterfly damper

What happens to the refrigerant as it flows through the evaporator in a DX system?

C) It absorbs heat and changes from a liquid to a vapor

How is an automatic fire damper typically activated in a vertical air duct?

C) By a fusible link or temperature sensor that releases when exposed to high heat

Which of the following components is NOT part of a typical Direct Expansion refrigeration system?

D) Cooling tower

What is the condition of the refrigerant entering the evaporator?

C) Low-pressure liquid

Which component in an indirect expansion, chilled water air conditioning system is responsible for cooling the water?

C) Chiller

Why does the refrigerant release heat in the condenser?

C) To change from a vapor to a liquid state

What role does the reheat coil play in controlling humidity in an air conditioning system?

B) It reheats the air after dehumidification to maintain temperature without adding moisture

What is the primary purpose of an automatic fire damper in an air duct?

B) To prevent the spread of smoke and flames through ductwork during a fire

Which of the following is an example of latent heat?

B) The heat needed to boil water

Which of the following is the primary function of an indirect expansion, chilled water air conditioning system?

B) To cool the air by circulating chilled water that transfers heat from the air to a refrigerant-cooled chiller

What is the state of the refrigerant after it leaves the compressor?

C) High-pressure vapor

Which of the following is an example of sensible heat?

C) The heat felt when a room is heated by a radiator

How can the cooling coil in an air conditioning system contribute to humidity control?

B) By condensing moisture from the air as it cools, thereby reducing humidity

Which of the following components ensures the correct flow and pressure of refrigerant in the system?

C) Expansion valve

What type of fluid is used as the heat transfer medium between the chiller and the air handling unit?

C) Chilled water

What does "latent heat" refer to in air conditioning?

C) The heat required for a substance to change its state without a temperature change

Where does the phase change of the refrigerant from liquid to vapor typically occur in an indirect expansion system?

B) In the chiller's evaporator

What is the physical state of the refrigerant as it exits the condenser?

C) High-pressure liquid

What is the function of the cooling tower in a chilled water system?

B) To cool the condenser water before it enters the condenser

Where are automatic fire dampers typically installed in an air conditioning system?

C) In vertical air ducts or ducts passing through fire-rated bulkheads and walls

What is the defining characteristic of a Direct Expansion (DX) refrigeration system in an air conditioning setup?

B) The refrigerant directly absorbs heat from the air and changes phase in the evaporator

Why is an indirect expansion system often preferred in large air conditioning installations?

C) It allows for centralized cooling and better temperature control across large spaces

How does the air cooler function in relation to the evaporator in a DX system?

B) The air cooler directs warm air over the evaporator coils where the refrigerant absorbs heat

What is the state of the refrigerant immediately after it passes through the expansion valve?

C) Low-pressure liquid-vapor mixture

Which of the following best illustrates specific humidity?

B) The weight of water vapor per kilogram of dry air

What is "specific humidity"?

B) The mass of water vapor per unit mass of dry air

What advanced system can be used to automatically maintain the desired humidity level?

B) An integrated building management system (BMS) with humidity sensors

Which damper type is designed to adjust automatically to regulate airflow based on pressure changes?

B) Pressure-controlled damper

What is the effect of an oversized air conditioning system on humidity control?

C) It may fail to remove enough humidity because it cools the space too quickly

What component in an air conditioning system is used to add moisture to the air when the relative humidity is too low?

B) Humidifier

What is one of the primary methods used to control relative humidity in an air conditioning system?

B) Using a humidifier or dehumidifier in conjunction with the system

What adjustment can be made to the air conditioning system to lower the indoor humidity level?

D) Decrease the airflow rate over the cooling coil
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