Simple installation

VAV SYSTEM FEATURES( One Of Many Types )

• Electric or Pneumaticor Digital Controls

• “In Duct” &/or “At Diffuser”Locations

• Pressure, Temperature And/Or Flow Sensors

------------------------------------------- VAV The Current State

Of TechnologyIn HVAC !

• Good site to visit & seeanimations of various VAV systems types!

• How different systems work and why !

POSSIBLEMAIN DUCT

VAV

Fan

Sp

eed

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Current Basic Commercial HVAC Systems

VAVs partial open Typically

Fan

17

HVACGeneral Rules of Installation

Distance from InDuct to Air Outlets.

Do not exceed 20 meters

It’s more of an art than a science.

Even the Prosdon’t always agree !

GENERAL COMMERCIAL “Duct Cell” PLACEMENT. You Have Two Options !

1] You can place ALL duct cell units in the “plenum”.

OR IF there are reasons that this approach might not work;

2] Then review the duct blueprint and split the duct system into sections that

have approximately the “ =< ft2 coverage” of the duct cell you have

selected . Then place a cell at any suitable upstream “insertion point”

for that section. REMEMBER: Sq Ft coverage ( 8’ ceilings) ~= CFM

Sum-total cfm = 3000

400cfm

400cfm

500cfm

500cfm

600cfm

600cfm

500cfm

500cfm

1000cfm

1000cfm

300 ft duct Plus anIn-line

VAV valve

Sum-totalcfm=3000

6000cfm

54” x 8”~3500 cfm

1750 sum cfmRadiusBends

50 ft

41” x 8”duct

EXAMPLE # 3

Bahrain- Multi Story Bldg - ½ of floor• Total of 5,118 sq ft per floor- 3 floors • 8 ft drop ceilings – 10 ft total• 4 air handlers = 2 mains & 2 overload• 1 cell guideline 2000 sq ft - very bad air

InsideWalls

2140 sum cfm

Possible cell locations

VCD boxReturn air registers

32”x 8”900cfm

Loading Issues • A/C only runs at night• Return air is Via dead space• Occupancy can spike to 150