hvac Flashcards
(20 cards)
What is the main purpose of an air-based HVAC system?
To provide conditioned air (heated, cooled, or fresh) to spaces.
What is the role of a boiler in an air-based system?
To generate hot water for heating purposes.
What does AHU stand for?
Air Handling Unit.
What is the function of an AHU?
It houses the fan that blows air across a heating or cooling coil to condition the air.
What does the heating coil contain in an air-based system?
Hot water from a boiler.
What is the return duct in HVAC?
It brings used air from the space back to the air handling unit.
What is the supply duct in HVAC?
It distributes conditioned air from the AHU to the building spaces.
Why is fresh air introduced into HVAC systems?
To replace stale air and improve indoor air quality.
What component helps clean the air in an AHU?
Filters.
How is humidity added or removed in HVAC systems?
By using humidifiers or dehumidifiers within the AHU.
Why isn’t 100% fresh air used all the time?
Because it would be inefficient and require more energy to condition outside air.
What is a refrigerant?
A fluid used in cooling systems that changes temperature with pressure.
What is the function of a compressor in a cooling system?
To increase the pressure and temperature of the refrigerant.
What happens to refrigerant in an expansion valve?
Its pressure drops, causing it to cool.
Why is coiling used in refrigerant loops?
To increase surface area for heat exchange.
What is a cooling tower used for?
To reject heat from the system by evaporating water.
Name the four loops in a complex cooling system.
Air side loop, chilled water loop, refrigerant loop, heat rejection loop.
What is a DX system?
A Direct Exchange system where refrigerant directly cools air without a chilled water loop.
What are the spatial design implications of HVAC systems?
Requires planning for mechanical rooms, duct routing, cooling towers, and AHU placement.
What is the benefit of chilled water over air for long-distance distribution?
Chilled water retains temperature better and requires smaller piping.
