Example Of Installation - Hitachi ECONO-FRESH KIT EF-5GE Installation Und Betriebsanleitung

3.4. INSTALLATION
3.4.1. DUCTING ARRANGEMENT.
This unit has been designed for positive introduction of
the outdoor air for free cooling or other control. Check to
ensure that the following points have been previously
designed or arranged:
1. Resistance of Outdoor Air Duct.
In order to protect against a shortage of outdoor air
intake or excessive intake of outdoor air, which cause
and insufficient capacity of free cooling or uncomfortable
change of supply air during free cooling operation, keep
the resistance of the outdoor air duct within the following
guide range:
½
P < P
R
P : Pressure Loss of Return Air Duct at Designed
R
Supply Air Volume
P : Pressure Loss of Outdoor Air Duct at Designed
O
Supply Air Volume, Including the Outdoor Air Filter.
NOTE:
The balance between the outdoor air volume and the
return air volume depends on the arrangement of the
discharge air duct, return air duct, and installed duct
arrangement. Refer to point 3 for obtaining the
general idea and Technical Catalogue for details.
2. Pressure Relief Damper
When the building is of an air-tight structure, positive
pressure inside the building will be created during the
free cooling or all-fresh operation.

3.4.2. EXAMPLE OF INSTALLATION

1. Ducting Connection
Pre-drilled duct flanges are provided at the supply,
return and outdoor air intake connections. It is
recommended that a flexible duct connection be
installed to minimize sound and vibration transmission.
Supply Air Duct
Refrigerant
Piping
< 4 x P
O R
(*) Insulate
(Field-Supplied)
5 mm
Econo-Fresh Kit
RPI-5HP Unit
AS Motor Cable
Thermistor
Return
(Accessory)
Cable
Air Duct
3. Outdoor Air Filter
Provide a field-supplied outdoor air filter in the outdoor
air duct.
External Static Pressure of
Indoor Fan
B
Air Flow
Balance of Air Flow and Resistance of each Duct.
A: Supply Air Flow when Fresh Outdoor Air damper is fully
closed (Return Air Damper is fully opened)
B: Supply Air Flow when Fresh Outdoor Air damper is fully
opened (Return Air Damper is fully closed)
P : Pressure Loss of Supply Air Duct.
D
Po: Pressure Loss of Fresh Outdoor Duct.
PR: Pressure Loss of Return Air Duct.
2. Insulation
All ducts should be insulated
Especially the outdoor air duct, through which the
-
cold outdoor air flows in, must be sufficiently
insulated.
The lowest temperature of the entering outdoor air
-
flowing through the outdoor air duct is the lowest
temperature for heating operation at the installation
site.
Downward
Outdoor Air Duct
Gradient of Duct
(Fully Insulated)
Outdoor Thermistor
(Field-Supplied)
(Accessory)
Pressure Relief
Damper
(If Required)
Return Air Filter
(Field-Supplied)
INSTALLATION
A
Rain Hood with
Bird Screen
(Field-Supplied)
3