Reciprocating Compressors

not exceed [_____] kW/kW kW/ton load at full load capacity. For

multicompressor units, not less than two independent refrigerant circuits

shall be provided. Chillers shall operate at partial load conditions

without increased vibration over normal vibration at full load, and shall

be capable of continuous operation down to minimum capacity. Provide

insulation for surfaces subject to sweating including the liquid cooler,

suction line piping, water boxes, economizer, and cooling lines. Insulation

shall conform to Section 15080 THERMAL INSULATION FOR MECHANICAL SYSTEMS.

2.2.1

Reciprocating Compressors

Provide with forced feed lubrication, crankcase heater, hot-gas muffler,

and suction strainer. Cylinder-unloading devices shall be unloaded when

compressor starts. Piston speed for open compressor shall not exceed

recommendations of manufacturer or 5 m/s 1000 fpm, whichever is less.

2.2.2

Helical Rotary Compressors

Positive displacement, oil-injected type, and driven by an electric motor.

Rotors shall be solid steel, Society of Automotive Engineers Grade 1141 or

1144. Shaft main bearings shall be either sleeve-design type with leaded

bronze or steel-backed babbit; or frictionless bearing design, ball or

roller type. Housings and covers shall be high-grade, cast-iron or

aluminum pressure castings. Lubrication system shall lubricate rotors,

bearings, shaft seal as well as rotor sealing and cooling. Provide an oil

safety cutout interlocked with the compressor starter to allow compressor

to operate only when the oil system is operational. Provide for

lubrication of bearings and shaft seals on shutdown with or without

electrical power supply.

2.2.3

Scroll Compressors

Three-dimensional, compliant, hermetically sealed design. Compressors

shall be mounted on vibration isolators. Rotating parts shall be factory

balanced. Main bearings shall be rolling-element type. Lubrication

systems shall be centrifugal pump type including oil level sight glass and

oil charging valve.

2.2.4

Liquid Coolers (Evaporators)

Tubes shall be seamless copper. On direct-expansion-type units, each

refrigerant circuit shall be complete with liquid solenoid valve and

expansion device capable of modulating to minimum capacity. For the water

side of liquid cooler, performance shall be based on a water velocity not

less than 0.91 m/s 3 fps and not more than 3.66 m/s 12 fpsand a fouling

factor of 0.00025.

2.2.5

Controls, Control Panels, and Gages

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NOTE: Specify required time delay for type and size

of unit after consulting current literature.

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NOTE: Specify lowest percent of full capacity

required. Check for availability before inserting

number in blank.

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SECTION 15601N

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