Gear Drive Advantage

A gear-driven compressor runs at higher impeller rotational speeds, but tends to have less vibration, and therefore less noise, than the larger, much heavier, direct drive units. Unique hydraulic bearings extend compressor durability.

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Easy BAS Integration & Chiller Plant Manager (CPM)

Daikin's exclusive Protocol Selectability^® feature offers factory-installed communication modules for BACnet®, LONWORKS® or Modbus® networks. QF selected BACnet communications for control and monitoring information to be sent to the BAS. This was accomplished without the need for costly gateways. The CPM offered by Daikin controls the primary chilled water pumps, condenser water pumps and cooling tower VFD, besides controlling the chiller plant.

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Power Loss Damage Protection

With the higher rotational speeds and much lighter running components compared to direct drive units, efficient hydrodynamic bearings are used. The shafts are supported on a film of lubricant, rather than running with metal-to-metal contact, typical of rolling element bearings. Under normal circumstances, the design life of the Daikin bearings is much longer than that of rolling element bearings. During the coast-down period, a compressed spring provides pressurized lubricant to the bearings. The compressors decelerate quickly due to low inertia. This is extremely useful while the compressor shuts down due to accidental power loss.

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Unloading to 10% Capacity

Daikin's centrifugal chillers offer unloading to 10% of full load for a single compressor chiller, without using inefficient hot gas bypass. This unloading capability, unique in the industry, provides improved stability of the chilled water temperature and less harmful cycling of compressors in installations subject to operation at low cooling loads. There are significant reasons for this beneficial operating characteristic, including:

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• ▶  Movable Diffuser: Daikin has pioneered the use of movable discharge geometry to lower the surge point of centrifugal compressors. The point at which the compressor enters a stall or surge condition generally limits compressor unloading. At low loads, low gas velocity through a fixed discharge area results in low gas velocities and the gas can stall or surge in the impeller. When in a stall condition, the refrigerant gas is unable to enter the volute due to its low velocity, and it remains stalled in the impeller. In a surge condition the gas rapidly reverses direction in the impeller, causing excessive vibration and heat. Daikin compressors reduce the discharge area as load decreases to maintain gas velocity and greatly reduce the tendency to stall or surge.
• ▶  Thermal Expansion Valves: There are three refrigerant control devices used in the industry: expansion valves, fixed orifices, and float systems. Of the three, only pilot operated thermostatic expansion valves, as used by Daikin, offer good refrigerant management throughout the entire chiller operating range. Expansion valves help the Daikin chillers achieve their industry leading capacity reduction capability.
• ▶  Liquid Injection: A small amount of liquid refrigerant is taken from the condenser and injected into the compressor discharge area. The liquid droplets absorb sound energy and reduce the compressor's overall sound level. The droplets evaporate and reduce discharge superheat.
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Cooling towers