APC InRow Specifications download pdf (Page 35)

990-4618C-001 InRow Chilled Water Air Conditioners Technical Specifications 29

Determining Cooling Capacity

IT equipment requires two acceptable limits in order for effective cooling to occur. These parameters are inlet

air temperature and flow rate of air through the IT equipment. It is entirely possible, though undesirable, to

design a computer room with enough heat removal capacity, but with an inadequate volumetric flow rate of

cool air supply. When this condition exists, IT equipment will be subjected to excessively high operating

temperatures on a localized basis due to recirculation, and cooling equipment will operate at less than optimal

efficiency. Schneider Electric provides the necessary data to prevent this undesirable situation. The first table,

titled “Recommended Capacity Limitations,” shows the capacity limits based on air flow of the InRow RC.

The following tables, titled “Performance Specifications”, show the recommended maximum amount of load

that should be placed upon the cooling unit solely based on heat removal capability. The lesser of the two

capacity numbers obtained from the “Recommended Capacity Limitations” table and “Performance

Specification” table should be considered the maximum load capable of being served by the InRow RC. A

definition of the terms in these tables follows:

IT equipment air flow (kW/CFM and kW/l/s) — The average cooling air flow rate demanded by IT

equipment in liters per second (cubic feet per minute) divided by the total actual power dissipation of IT

equipment in kilowatts.

Recommended capacity limit (kW) —The corresponding maximum load in kilowatts capable of being

served by the cooling unit solely based on conservation of volumetric air flow.

DB (°C and °F) — The dry bulb temperature in degrees Fahrenheit and Celsius of the return air stream to the

cooling unit.

WB (°C and °F) — The wet bulb temperature in degrees Fahrenheit and Celsius of the return air stream to the

cooling unit.

CW delta T (°C and °F) — The difference in temperature in degrees Fahrenheit and Celsius between chilled

water entering and exiting the cooling unit.

Sensible net capacity (kW and BTU/hr) — The sensible net heat removal capacity of fan heat, of the cooling

unit at stated operating conditions.

Total net capacity (kW and BTU/hr) — The total (sensible + latent) net heat removal capacity of fan heat, of

the cooling unit at stated operating conditions.

Sensible heat ratio (SHR) — The sensible heat ratio of the unit at stated conditions. Sensible Heat Ratio is the

ratio of sensible capacity to total capacity.

CW flow rate (l/s and GPM) — The volumetric flow rate of chilled water through the cooling unit in gallons

per minute, and liters per second, that is required to result in the stated performance. For base loads,

ACRC301S units should not have a flow rate greater than 1.3l/s (20.8 GPM), ACRC301H units should not

have a flow rate greater than 1.95 l/s (30.9 GPM), and ACRC500/ACRP500 series units should not have a flow

rate greater than 2.08 l/s (33 GPM); peak loads may exceed these flow rates by up to 25 percent for short time

spans.

Total CW pressure drop (kPa and ft H

O) — The differential pressure observed between inlet and outlet

chilled water connections for the stated CW flow rate.

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APC InRow Specifications Page 35