ASHRAE Journal - February 2022 - 57

TECHNICAL FEATURE
pilot building, estimate the power consumption, select
an appropriate EUI that considers energy and area, calculate
EUI baseline, benchmark the building to other
similar buildings, conduct ASHRAE level II audit, and set
EUI target.
Building Information
General
Age: Built around 1989 (35+ years).
Location: 100 km (62 mi) from Riyadh, Saudi Arabia.
Building Function: Unmanned communications
building, which hosts radio, telephone and IT infrastructure
and support facilities (HVAC, dc power system,
fi re system, lighting, backup power generator, and
access control system) to provide secure and reliable
environment for operation of building.
Area: 375 m2 (4036 ft2), length 25 m × width 15 m
(82 ft × 49 ft)
Floors: 1
Operation: 24/7, Unmanned Loads: Critical IT ac and
dc equipment, dc power plant, HVAC, lighting, plug
load, water heating and miscellaneous (fi re, safety and
access controls).
Wall Construction: As-built drawing from 1988 shows
that the external walls have a total thickness of 350 mm
(13.8 in.) consisting of 200 mm (7.9 in.) thick CMU (concrete
masonry unit), 50 mm (2 in.) thick polystyrene
insulation board and 100 mm (3.9 in.) CMU. Internal
walls are covered with 15 mm (0.6 in.) thick gypsum
board walling.
Roof Construction: As-built drawing from 1988 shows
fl at roof consisting of 250 mm (9.8 in.) steel-framed concrete
slab. Insulation consists of waterproofi ng membrane
covered with a layer of aggregate gravels. The roof
is sloped for water draining. The ceiling appears to have
cable trays covered with rectangular panels.
Windows: None.
Doors: Single and double doors for air lock. As per
as-built drawings, doors are bulletproof, fi re rated
with security entry and exit as per Saudi Aramco
requirements.
Envelope Air Tightness: Good weather stripping on
doors and cabling penetration to the building with suffi
cient air lock.
Fuel Used: Electricity provided by utility with diesel
generator backup.
TABLE 1 Main differences between critical (precision) and comfort cooling.
PRECISION AIR
CONDITIONING
APPLICATION
RANGE OF COOLING/HEATING
CAPACITY PER INDIVIDUAL AIR
CONDITIONING UNIT
PROPORTION OF CAPACITY
SENSIBLE/LATENT
CONTROL ACCURACY
Cooling for Critical
Electronic
Applications
5 kW to 150 kW
(Partially Modular)
85% to 100%/
0% to 15%
0.5 K/+3%
Relative Humidity
HUMIDITY REGULATION
Controlled Humidity
(To Help Avoid
Electrostatic Charge)
AIR VOLUME
AIR OUTLET SPEED
5,000 m3/h to
30,000 m3/h
2.3 m/s
NOISE LEVEL IN ROOM 45 dB(A) to 70 dB(A)
DELIVERY OF OPTIONS
OPERATOR CONTROLS
CYCLE OF OPERATION
SOFTWARE AND FIRMWARE
UPDATES
USED WITH RAISED FLOOR
INSTALLATION
Very Large, Due to
Individual Production
More Intricate
24/7/365 Operation
Needed on a
Regular Basis
In Most Cases
COMFORT AIR
CONDITIONING
Room Air
Conditioning for Human
Occupants
2.30 kW
50% to 70%/
30% to 50%
1.2 K
Unregulated
Dehumidifi cation
(For Comfortable
Environment Cooling)
300 m3/h to 2,000 m3/h
0.2 m/s to 0.5 m/s
20 dB(A) to 40 dB(A)
Lower, Due to
Mass Production
Basic Temperature
Setting
Seasonal Operation With
Time-Dependent
Setpoint Changes
Not Normally Required
Very Rarely
On-Site Power Metering
A current transformer data logger was installed at the
main building incoming feeder and, therefore, data
logger readings and recordings were available for a onemonth
period.
Measurement was recorded every 15 minutes capturing
amperage (Amps), power (kW), active power (KVA),
reactive power (KVAR), energy (kWh) and power factor
(%). The collected data was quality inspected for compliance
with the equation KVA2 = kW2 + KVAR2. However,
small differences were found, which were attributed to
harmonics inside the building. Figure 1 depicts the raw
instantaneous power demand along the monitoring
F E B R U A RY 2 0 2 2 ashrae.o rg ASHRAE JOURNAL
57
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ASHRAE Journal - February 2022

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