Setting The Air Conditioners - Mitsubishi Electric PUHY-P250YHM-A Data Book

8-5 Setting the Air conditioners

(1) Air-Conditioning Load
1 Once the floor plan is made and the conditions for the air-conditioning system are set, air conditioning
capacity has to be determined by calculating the load.
2 Unlike the outdoor air, computer load remains constant throughout the year. However, it is possible
that there are considerable fluctuations within a day. This is due to the fact that, depending on the time
of the day, there are changes in the number of computers that are turned on and that the different
computer systems are in operation.
3 If there is a plan to expand the current computer system in the future, it is important to include the
load for the units to be added in the future when calculating the thermal load because it is practically
impossible to keep the computers off for days on end during the installation of the new units.
4 The following items need to be checked before calculating the unit capacity:
· Floor area of the computer room (m
· Total quantity of heat generated by computers
(2) Sample Selection of Air Conditioners
(2-1) Conditions
Computer-generated heat
Number of workers
Lighting
Temperature and humidity
Frequency
(2-2) Building Conditions
Windows
Inside Measurement
Surroundings
1 Coefficient of Overall Heat Transmission U (W/m
Outer Walls
Inner Walls
Ceiling
Floor (free access)
Floor
Windows
2 Internal Load
Number of People in the Room 5
Lighting
Calculator
Draft
3 Volume of Outdoor Air Intake
3
25m /h·person
2 )
Indoor ˚CDB/Indoor WBT : 24˚C/17˚C
˚CDB of the air going into the computer
(W: 4.5m, H: 1.5m)
Upstairs room, downstairs room, heat and air conditioning
Summer 3.6, Winter 3.8
2.05
Downward convection 3.36, upward convection 3.3
Downward convection 3.05, upward convection 4.56
Downward convection 2.42, upward convection 3.3
Summer 5.93, Winter 6.5
2
20W/m
20.9kW
0.2 times/h
38
20.9kW
5
2
20W/m
: 18˚C
60Hz
✕
2
Ceiling height 2.2m
2 ·K)
Window