Air Conditioning The Computer Room; Main Features Of The Floor-Duct Air Conditioners; Features Of Air-Conditioner For Computer Room - Mitsubishi Electric PUHY-P250YJM-A Data Book

V Wiring Design (PEFY-AF1200CFMR)
V

Air Conditioning the Computer Room

1. Main Features of the Floor-Duct Air Conditioners

This system is installed by building a floor over an existing floor and using the space between these two floors as an
air-conditioning duct. This system has the following characteristics:
ŒThe temperature and humidity can efficiently and reliably be controlled, since the air-conditioned air is sent directly to the
machine.
ŒIt provides a comfortable environment for the operator, since the air can be conditioned to best suit the needs of the operator
and machines.
ŒIt is favorable in terms of appearance because the air-conditioning duct is out of sight.
ŒThe location of the duct is irrelevant when considering adding new machines or rearranging the existing machines, since
the entire floor serves as the air duct.
Free-access top floor
CAUTION
ŒUnlike plenum ventilation and overhead-duct type conditioners, since the conditioned air is not mixed with the air in the room,
the air that comes out of the unit has to meet the predetermined conditions (constant temperature/constant humidity) at the
time the air exits the unit.
Close attention must be paid to the auto-controlling system.
ŒDust in the duct space (between the free-access top floor and the existing floor) must be thoroughly removed before
installing the unit.
ŒSince the existing floor is cooled by the unit, it may produce dews on the ceiling of the room down below.

2. Features of air-conditioner for computer room

Air-conditioner for computer room is designed to maintain a constant room temperature and humidity. For underfloor air supply
systems, providing air that meets predetermined requirements is a must.
The compressor installed in this unit runs year around.
The capacity controlled compressor regulates the outlet air temperature (or inlet air temperature) depending on the load
change.
The humidifier (Configure to Order) installed in this unit humidifies a room to a target humidity, and regulates the humidity.
With priority dehumidification control (a dehumidifier must be installed on site), a room is dehumidified to a target humidity.
Since the reheat function is not equipped, the room temperature may drop below the predetermined temperature due to a load
inside the room.
Therefore, the absolute humidity drops whereas the relative humidity may not drop to a target humidity.
Ceiling
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