Post on 27-May-2020
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Ventilation
2 Ventilation and Air-conditioning
Systems
Vladimír Zmrhal (room no. 814)
http://users.fs.cvut.cz/~zmrhavla/index.htmDptDpt. . OfOf
EnvironmentalEnvironmental
EngineeringEngineering
2
�Ventilation systems
Natural ventilation
� is the flow of outdoor air caused by wind and air density
differences
Mechanical (forced) ventilation
� is driven by mechanical work - fan
Hybrid ventilation
� combination of natural and mechanical ventilation
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� natural ventilation by louvers (permanent)
� shaft ventilation (permanent)
� interupted natural ventilation (time limited)
� infiltration (time limited)
Natural ventilation
heat source
depends on
external (ambient)
climatic conditions
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Mechanical ventilation
Air exchange in the room:
� exhaust-only ventilation system
� supply-only ventilation system
� supply and exhaust ventilation system
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5
Exhaust-only ventilation systems
Mechanical ventilation
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Mechanical ventilation
Local exhaust ventilation systems
� unitary exhaust
� central exhaust
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7
Supply-only ventilation system
Mechanical ventilation
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Supply and exhaust ventilation system
Mechanical ventilation
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9
Supply and exhaust ventilation system
� recirculation without exhaust
Mechanical ventilation
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Supply and exhaust ventilation system
� recirculation with exhaust
Mechanical ventilation
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Supply and exhaust ventilation system
� with heat recovery, recirculation, heating, cooling (drying),
humidifying, double filtration
Mechanical ventilation
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Pressure condition of the space:
�underpressure
Vs< V
exusually 15 - 30 Pa
400 Pa for work with radioactive materials
� overpressure
Vs> V
exe.g. clean rooms, operating room, …
min. 10 -15 Pa
� balanced
Vs= V
ex
Mechanical ventilation
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13
Local air supply
For local conditioning of air temperature or cleanlines
� air curtain
� air shower
� personalized ventilation
Mechanical ventilation
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Air curtain
a) door curtain with upward supply
b) two side curtain
Local air supply
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Air shower
� people protection in hot industrial work places with radiation
(steel foundry,…)
� higher air convection
Local air supply
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Personalized ventilation
� outdoor air supply directly to the breathing zone
Local air supply
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Hybrid ventilation
Solar chimney
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Heat Transfer
- convective
- radiant
Air-conditioning
Medium
- air
- water
- air + water
- refrigerant
Purpose
- comfort
- technology
- biology
- safety
Number of zones
- one - zone
- multizone
→→→→ single-duct, dual-duct
→→→→ cooled ceilings, fan coil units
→→→→ induction units (chilled beams)
→→→→ split, multisplit, VRV
Air-conditioning
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Air-conditioning
Single-duct air system with constant air flow
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Air-conditioning
Single-duct air system – VAV (variable air volume)
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Air-conditioning
Dual-duct air system
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Air-conditioning
Fan-coil unit system
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Air-conditioning
Induction unit, Chilled beams system
VP
P
VOb
Ob=I
OhOb, ChOb
Oh, Ch
Prim
VP
P
VOb
Ob=I
OhOb, ChOb
Oh, Ch
Prim
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Air-conditioning
Cooled ceiling system
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Air-conditioning
Refrigerant systems
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Split Multi-split VRV
Air-conditioning
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Thank you for your
attention