Constant air volume
Constant air volume (CAV) is a type of heating, ventilating, and air-conditioning (HVAC) system. In a simple CAV system, the supply air flow rate is constant, but the supply air temperature is varied to meet the thermal loads of a space.[1]
Most CAV systems are small, and serve a single thermal zone. However, variations such as CAV with reheat, CAV multizone, and CAV primary-secondary systems can serve multiple zones and larger buildings.
In mid- to large-size buildings, new central CAV systems are somewhat rare. Due to fan energy savings potential, variable air volume (VAV) systems are more common. However, in small buildings and residences, CAV systems are often the system of choice due to their simplicity, low cost, and reliability. Such small CAV systems often have on/off control, rather than supply air temperature modulation, to vary their heating or cooling capacities.
There are two types of CAV systems that are commonly in use to modify the supply air temperature: the terminal reheat system and the mixed air system.[2]
The terminal reheat system cools the air in the air handling unit down to the lowest possible needed temperature within its zone of spaces. This supplies a comfortable quality to the space, but wastes energy.
The mixed air system has two air streams, typically one for the coldest and one for the hottest needed air temperature in the zone. The two air streams are strategically combined to offset the space's load. The mixed air system option is not as proficient at controlling the humidity, yet it does do well at controlling the temperature.[3]
References
- v
- t
- e
concepts
- Air changes per hour
- Bake-out
- Building envelope
- Convection
- Dilution
- Domestic energy consumption
- Enthalpy
- Fluid dynamics
- Gas compressor
- Heat pump and refrigeration cycle
- Heat transfer
- Humidity
- Infiltration
- Latent heat
- Noise control
- Outgassing
- Particulates
- Psychrometrics
- Sensible heat
- Stack effect
- Thermal comfort
- Thermal destratification
- Thermal mass
- Thermodynamics
- Vapour pressure of water
- Absorption-compression heat pump
- Absorption refrigerator
- Air barrier
- Air conditioning
- Antifreeze
- Automobile air conditioning
- Autonomous building
- Building insulation materials
- Central heating
- Central solar heating
- Chilled beam
- Chilled water
- Constant air volume (CAV)
- Coolant
- Cross ventilation
- Dedicated outdoor air system (DOAS)
- Deep water source cooling
- Demand controlled ventilation (DCV)
- Displacement ventilation
- District cooling
- District heating
- Electric heating
- Energy recovery ventilation (ERV)
- Firestop
- Forced-air
- Forced-air gas
- Free cooling
- Heat recovery ventilation (HRV)
- Hybrid heat
- Hydronics
- Ice storage air conditioning
- Kitchen ventilation
- Mixed-mode ventilation
- Microgeneration
- Passive cooling
- Passive daytime radiative cooling
- Passive house
- Passive ventilation
- Radiant heating and cooling
- Radiant cooling
- Radiant heating
- Radon mitigation
- Refrigeration
- Renewable heat
- Room air distribution
- Solar air heat
- Solar combisystem
- Solar cooling
- Solar heating
- Thermal insulation
- Thermosiphon
- Underfloor air distribution
- Underfloor heating
- Vapor barrier
- Vapor-compression refrigeration (VCRS)
- Variable air volume (VAV)
- Variable refrigerant flow (VRF)
- Ventilation
- Water heat recycling
- Air conditioner inverter
- Air door
- Air filter
- Air handler
- Air ionizer
- Air-mixing plenum
- Air purifier
- Air source heat pump
- Attic fan
- Automatic balancing valve
- Back boiler
- Barrier pipe
- Blast damper
- Boiler
- Centrifugal fan
- Ceramic heater
- Chiller
- Condensate pump
- Condenser
- Condensing boiler
- Convection heater
- Compressor
- Cooling tower
- Damper
- Dehumidifier
- Duct
- Economizer
- Electrostatic precipitator
- Evaporative cooler
- Evaporator
- Exhaust hood
- Expansion tank
- Fan
- Fan coil unit
- Fan filter unit
- Fan heater
- Fire damper
- Fireplace
- Fireplace insert
- Freeze stat
- Flue
- Freon
- Fume hood
- Furnace
- Gas compressor
- Gas heater
- Gasoline heater
- Grease duct
- Grille
- Ground-coupled heat exchanger
- Ground source heat pump
- Heat exchanger
- Heat pipe
- Heat pump
- Heating film
- Heating system
- HEPA
- High efficiency glandless circulating pump
- High-pressure cut-off switch
- Humidifier
- Infrared heater
- Inverter compressor
- Kerosene heater
- Louver
- Mechanical room
- Oil heater
- Packaged terminal air conditioner
- Plenum space
- Pressurisation ductwork
- Process duct work
- Radiator
- Radiator reflector
- Recuperator
- Refrigerant
- Register
- Reversing valve
- Run-around coil
- Sail switch
- Scroll compressor
- Solar chimney
- Solar-assisted heat pump
- Space heater
- Smoke canopy
- Smoke damper
- Smoke exhaust ductwork
- Thermal expansion valve
- Thermal wheel
- Thermostatic radiator valve
- Trickle vent
- Trombe wall
- TurboSwing
- Turning vanes
- Ultra-low particulate air (ULPA)
- Whole-house fan
- Windcatcher
- Wood-burning stove
- Zone valve
and control
- Air flow meter
- Aquastat
- BACnet
- Blower door
- Building automation
- Carbon dioxide sensor
- Clean air delivery rate (CADR)
- Control valve
- Gas detector
- Home energy monitor
- Humidistat
- HVAC control system
- Infrared thermometer
- Intelligent buildings
- LonWorks
- Minimum efficiency reporting value (MERV)
- Normal temperature and pressure (NTP)
- OpenTherm
- Programmable communicating thermostat
- Programmable thermostat
- Psychrometrics
- Room temperature
- Smart thermostat
- Standard temperature and pressure (STP)
- Thermographic camera
- Thermostat
- Thermostatic radiator valve
trades,
and services
- Architectural acoustics
- Architectural engineering
- Architectural technologist
- Building services engineering
- Building information modeling (BIM)
- Deep energy retrofit
- Duct cleaning
- Duct leakage testing
- Environmental engineering
- Hydronic balancing
- Kitchen exhaust cleaning
- Mechanical engineering
- Mechanical, electrical, and plumbing
- Mold growth, assessment, and remediation
- Refrigerant reclamation
- Testing, adjusting, balancing
organizations
- Indoor air quality (IAQ)
- Passive smoking
- Sick building syndrome (SBS)
- Volatile organic compound (VOC)
- ASHRAE Handbook
- Building science
- Fireproofing
- Glossary of HVAC terms
- Warm Spaces
- World Refrigeration Day
- Template:Home automation
- Template:Solar energy
This engineering-related article is a stub. You can help Wikipedia by expanding it. |
- v
- t
- e