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5.10 Important Refrigeration Components
5.10.1 Variable Capacity Compressor with VFD
The unique feature of the gForce Ultra is the application of variable capacity compressor. The quest for
greater energy efficiency is continuous; efficiency benchmarks are always moving up. That’s why Data
Aire is moving toward variable capacity compressor technology for quieter, more energy-saving perfor
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mance. Conventional compressors are designed to run at constant speed to handle a given capacity
requirement. But in data center applications, the capacity requirement varies. In these situations, a
constant speed compressor uses various capacity-regulation techniques and can be less efficient than
a compressor utilizing variable capacity technology. A variable capacity compressor (VCC), on the
other hand, saves energy and operates more quietly by varying speed to match the workload. Tests
with VCC compressors have shown an immediate energy savings and sound level reductions.
5.10.2 Electronic Expansion Valve
The Electronic Expansion Valve (EEV) is standard for this unit. This high efficiency feature provides an
EEV in place of the standard Thermal Expansion Valve (EEV). The EEV controls superheat through the
dap4™ controls by actively measuring suction pressure via a transducer attached to the suction line
and suction temperature via a thermal transducer strapped to the suction line. The EEV actively adjusts
the orifice size and resulting mass flow of refrigerant to maintain the superheat setpoint. The EEV
maintains more stable system balance and is more energy efficient. With variable capacity systems,
an electronic expansion valve is the solution to handle refrigerant mass flow variations.
5.10.3 High Pressure Cutout Switch
Each refrigerant circuit is protected by a high pressure cutout switch with manual reset button. The
switch is typically located in the evaporator near the compressor. The high pressure switch rating is:
R-410A Refrigerant
Setting
Cut-out (Open)
575 PSI
Cut-in (Close)
Manual Reset
5.10.4 Low Pressure Cutout Switch
Each refrigerant circuit has a low pressure cutout switch which features SPST open-low switch action
and automatic reset. The switch is typically located in the evaporator near the compressor. The low
pressure switch rating is:
R-410A Refrigerant
Setting
Cut-out (Open)
50 PSI
Cut-in (Close)
90 PSI
Summary of Contents for gForce Ultra
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