Ventilation
2 Ventilation and Air-conditioning
Systems
Vladimír Zmrhal (room no. 814)
Dpt.
Dpt. Of
http://users.fs.cvut.cz/~zmrhavla/index.htm Environmental
Engineering
1
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
1
Natural ventilation
natural ventilation by louvers (permanent)
shaft ventilation (permanent)
heat source
interupted natural ventilation (time limited)
infiltration (time limited)
depends on
external (ambient)
climatic conditions
Mechanical ventilation
Air exchange in the room:
exhaust-only ventilation system
supply-only ventilation system
supply and exhaust ventilation system
2
Mechanical ventilation
Exhaust-only ventilation systems
Mechanical ventilation
Local exhaust ventilation systems
unitary exhaust
central exhaust
3
Mechanical ventilation
Supply-only ventilation system
Mechanical ventilation
Supply and exhaust ventilation system
4
Mechanical ventilation
Supply and exhaust ventilation system
recirculation without exhaust
Mechanical ventilation
Supply and exhaust ventilation system
recirculation with exhaust
10
5
Mechanical ventilation
Supply and exhaust ventilation system
with heat recovery, recirculation, heating, cooling (drying),
humidifying, double filtration
11
Mechanical ventilation
Pressure condition of the space:
underpressure
Vs < Vex usually 15 - 30 Pa
400 Pa for work with radioactive materials
overpressure
Vs > Vex e.g. clean rooms, operating room, …
min. 10 -15 Pa
balanced
Vs = Vex
12
6
Mechanical ventilation
Local air supply
For local conditioning of air temperature or cleanlines
air curtain
air shower
personalized ventilation
13
Local air supply
Air curtain
a) door curtain with upward supply
b) two side curtain
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7
Local air supply
Air shower
people protection in hot industrial work places with radiation
(steel foundry,…)
higher air convection
15
Local air supply
Personalized ventilation
outdoor air supply directly to the breathing zone
16
8
Hybrid ventilation
Solar chimney
17
Air-conditioning
Air-conditioning
Heat Transfer Number of zones Purpose
- convective - one - zone - comfort
- radiant - multizone - technology
- biology
- safety
Medium
- air → single-duct, dual-duct
- water → cooled ceilings, fan coil units
- air + water → induction units (chilled beams)
- refrigerant → split, multisplit, VRV
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9
Air-conditioning
Single-duct air system with constant air flow
19
Air-conditioning
Single-duct air system – VAV (variable air volume)
20
10
Air-conditioning
Dual-duct air system
21
Air-conditioning
Fan-coil unit system
22
11
Air-conditioning
Induction unit, Chilled beams system
P
OhOb, ChOb VP
Oh, Ch
VOb
Ob=I
Prim
23
Air-conditioning
Cooled ceiling system
24
12
Air-conditioning
Refrigerant systems
25
Air-conditioning
Split Multi-split VRV
26
13
Thank you for your
attention
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