B09_40534737_AM02_Att1a_Chiller_Specification_0002.pdf

BUILDING NO. SC#

PROJECT NAME

BITH 236427-1

Air-Cooled Water Chiller

SECTION 236427 – AIR-COOLED WATER CHILLERS

PART 1 - GENERAL

1.1 SUMMARY

A. Related Documents:

1. Drawings and general provisions of the Subcontract apply to this Section.

2. Review these documents for coordination with additional requirements and information that apply to work under this Section.

B. Section Includes:

1. Design and construction of air-cooled chiller

2. Starters with disconnect switches

3. System control panel

4. Refrigerant charge, oil, and like start-up materials

5. Testing, start-up and instruction

6. Manufacturer’s field services for start-up and instruction.

C. Related Sections:

1. Division 01 Section "General Requirements."

2. Division 23 Section "Testing, Adjusting, and Balancing".

3. Division 23 Section "Instrumentation and Controls for HVAC".

4. Division 23 Section "Refrigerant Piping".

5. Division 23 Section "HVAC Pumps".

6. Division 23 Section "Fan Coil Units".

7. Division 23 Section "Indoor Central Station Air Handling Units with Coils".

8. Division 26 Section “Electrical Materials and Methods".

1.2 REFERENCES

A. General:

1. The following documents form part of the Specifications to the extent stated. Where differences exist between codes and standards, the one affording the greatest protection shall apply.

2. Unless otherwise noted, the referenced standard edition is the current one at the time of commencement of the Work.

3. Refer to Division 01 Section "General Requirements" for the list of applicable regulatory requirements.

4. Refer to Division 23 Section "Common Results for HVAC" for codes and standards, and other general requirements.

B. Air Conditioning and Refrigeration Institute (ARI):

1. ARI 550 Centrifugal and Rotary Screw Water-Chilling Packages

2. ARI 575 Method of Measuring Machinery Sound within an Equipment Space

C. American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE):

1. ASHRAE 15 Safety Code for Mechanical Refrigeration

2. ASHRAE 30 Methods of Testing Liquid Chilling Packages

D. American Society of Mechanical Engineers ASME:

1. BPVC Boiler and Pressure Vessel Code

E. ASTM International:

1. ASTM C 117 Test Method for Materials Finer than 75-Micrometer (No. 200) Sieve in Mineral

Aggregates by Washing

2. ASTM C 335 Test Method for Steady-State Heat Transfer Properties of Horizontal Pipe Insulation

F. National Electrical Manufacturers Association (NEMA):

1. NEMA 250 Enclosures for Electrical Equipment (1000 Volt Maximum)

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2. NEMA ICS 6 Enclosures for Industrial Control and Systems

G. National Fire Protection Association NFPA 70 National Electrical Code

H. National Institute of Occupational Safety and Health NIOSH TC-13F-4

I. Underwriters Laboratories, Inc. (UL)

J. 40 CFR Part 82 Protection of Stratospheric Ozone

K. National Electrical Manufacturers Association NEMA 250 Enclosures for Electrical Equipment (1000 Volt Maximum)

1.3 PERFORMANCE REQUIREMENTS

A. The refrigeration machine system shall include piping within the machine up to and including the flanged connection for chilled-water and condenser-water inlets and outlets; and control equipment and wiring within the machine, including the chilled-water and condenser pressure-differential switches, the unit-mounted variable frequency drive, auxiliary oil-pump starter and control and instrumentation devices specified.

B. Refrigerant: Refrigeration machine shall use R410Aa refrigerant.

C. Compressor assembly vibration shall not exceed 1.0 mil (0.03 mm) at the bearings.

1.4 SUBMITTALS

A. Submit under provisions of Division 23 Section "Common Results for HVAC, Review of Materials and Division 01 Section "General Requirements."

B. Shop Drawings:

1. Drawings of refrigeration machine, including dimensions prior to manufacture.

2. Complete wiring diagrams specifically for the proposed equipment. Include required wiring between unit and starter. Indicate locations of conduit connections.

C. Product Data:

1. Refrigeration machine description and data, addressing items to be provided.

2. Sound-power data by octave band, at 100 percent of full load.

D. Test Data: Certified test report as specified in subpart 2.12, “Source Quality Control.”

PART 2 - PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Carrier, Trane, York.

2.2 CAPACITIES AND CHARACTERISTICS

A.

1. Unit Nominal Tonnage: 18.96 tons.

2. Cooling Efficiency: 9.530 EER

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3. Number of Compressors: 2

4. Number of capacity Steps: 2

5. Total Power: 23.87 kW

6. Sound Pressure: 61 dBA at 30 feet

2.3 AIR-COOLED CHILLERS

A. General:

1. Type: Motor-driven hermetic or open, rotary, scroll or centrifugal water-chilling machine, complete with accessories.

B. Compressor:

1. Each unit shall be equipped with a direct-drive compressor, operating at not more than 35,000 rpm, driven by a squirrel-cage induction motor. Units with speed-increasing gears shall operate between 10,000 and 30,000 rpm.

2. The compressor shaft-and-impeller assembly, and the rotor-shaft [-gear] assembly shall both be statically and dynamically balanced. There shall be no critical speed within the compressor operating range.

3. Select compressor to ensure stable operation at operating points from 15 percent to maximum-rated load at design conditions.

4. The rotor shall be built of noncorrosive material, unaffected by refrigerant contact. Compressor casing construction shall permit removal of rotor shaft. Provide casing joints with gaskets of suitable material to prevent inward and outward leakage.

5. Impellers shall be cast from high-strength aluminum alloy, balanced both statically and dynamically.

Impeller shall be proof-tested at least 15 percent above design operation speed.

6. Capacity control shall be by variable inlet guide vanes, automatically controlled, and capable of modulating performance from 15 percent to 100 percent rated unit capacity without surging. Provide single-stage units or three-stage units with inlet vanes in front of only one compression stage.

7. Provide suitable means to prevent entrained liquid from entering the compressor, and uniformly distributing the liquid refrigerant. Provide float-valve housing and float box, ASME BPVC-approved receding-type, spring-loading, relief valve suitable for attachment of relief piping (in accordance with applicable codes) and liquid-level sight gauge. Isolate vent piping from the relief valve with an ASME BPVC-approved isolation device in the piping. Provide braided flexible pipe connections to vent piping. Valve shall vent only enough refrigeration to relieve pressure, not the full refrigeration charge.

Install the vent piping in accordance with ASHRAE 15 and ASME BPVC.

C. Evaporator and Condenser:

1. Type: Construct of welded steel, in accordance with ASME BPVC Sec VIII for positive-pressure machines, and design for water circulation quantity scheduled. The total water side pressure drop from inlet to outlet shall not exceed that scheduled.

2. Tubes: Construct of 0.035 inch (9 mm) thick copper, rolled into grooved holes in the tube sheet and removable without affecting the strength or durability of the tube sheet or causing leakage at adjacent tubes. Water velocity in the tubes shall not exceed 10 fps.

3. Tube Sheet: Construct of carbon steel, welded to the shell. Provide sufficient intermediate tube sheets to prevent tube vibration, and space tube supports at no greater interval than 5 feet.

4. End Covers: Provide removable end covers on the condenser tube bundle constructed of high-grade fabricated steel, or other material suitable for the specified pressures. Each separable cover shall be removable so that the complete tube sheet can be exposed for cleaning.

5. Connections: Provide a 1 inch (25 mm) valved drain connection, and a 1 inch (25 mm) vent connection on each water box.

6. Relief Valve: Provide a relief valve to release refrigerant where recommended by the manufacturer.

7. Baffles: Provide suitable baffles to prevent direct impingement of gases upon the tubes, and to distribute the gas uniformly over the length of the condenser. Provide a carbon-steel baffle sheet, to segregate and collect the noncondensible gases for purging. Sheet shall be sufficiently thick enough to prevent corrosion of the condenser shell. Include a properly located connection to remove noncondensible gases and water vapor through purge and recovery units.

D. Motor:

1. Cable Connection Box: Provide a suitable cable connection box so mounted to provide full access to terminals. The cable connection box shall be capable of accepting the necessary feeder conductors.

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Size the cable terminals for the full-load current and suitabilities to accept copper conductors without excessive heating.

2.4 CONTROLS

A. Microprocessor Panel: Provide microprocessor panel for each unit, with individual gauges, and minimum 20-character light-emitting diode (LED) screen indicating purge-condenser drum pressure, high-, low-, and differential-oil pressure, evaporator-refrigerant pressure, condenser refrigerant pressure, evaporator entering and leaving temperatures, condenser entering and leaving temperatures, percent motor current, and operating hours. This panel shall contain switches to permit manual or automatic operation of the oil pump and purge pump; switch to operate purge oil-separator heater and pilot light to indicate its operation; front mounted rocker-switch with separate pilot light providing system energization and refrigeration machine AUTO-OFF control. Provide monitoring of low-evaporator temperature and differential oil-pressure cutouts. The panel shall contain a capacity control mechanism that limits the maximum amperage drawn by the compressor motor, by monitoring motor amperage and the inlet guide vanes.

B. Electronic temperature controller shall be capable of maintaining the set-point temperature to within 1°F (0.5°C). It shall have field-adjustable ramp-function loading to permit the rate at which the refrigeration machine is allowed to load from start to full load to be varied between 6 to 24 minutes. Temperature set-point shall be adjustable with a calibrated dial on the front panel.

2.5 INSULATION

A. Insulation: Flexible, elastomeric, closed-cell sheet insulation, 3/4 inch (20 mm) thick, suitable for outdoor installation; with a K factor not exceeding 0.27 at 75 deg F (24 deg C) mean temperature in accordance with ASTM C 177, and a water-vapor permeability of 0.15 perm-inch or less in accordance with ASTM E 96, procedure B; Armstrong “AP Armaflex,” Rubatex Corp. “R1800FS,” or equal.

B. Adhesive: Armstrong “520,” Rubatex Corp. “R373,” or equal adhesive recommended by the insulation manufacturer for this application.

C. Factory insulate cold surfaces of the refrigeration machine, except uni-shell vessels (cooler/condenser in one shell) shall be insulated in their entirety, including the condenser section.

D. Apply the insulation to the surface with adhesive over the entire surface and seal butt joints with adhesive.

Insulation installation shall be in accordance with application recommendations described in the Armstrong pamphlet “Specifications - Installation of Armaflex Insulations,” IP-2268, or comparable manufacturer’s printed installation recommendations.

E. Field insulate areas that show evidence of sweating during operation, using the same materials as the factory insulation.

F. Factory paint insulation and joint material to match refrigeration machine color; Armstrong “WB Armaflex Finish,” Rubatex Corp. “R374,” or equal water-based latex enamel coating for use over insulation provided.

2.6 FACILITIES MONITORING AND CONTROL (FMCS) INTERFACE

A. The chiller control system shall be compatible with building and provide a single point of interface of the chillers to the facility FMCS. Be responsible for hardware, software required.

1. The FMCS subcontractor shall wire the FACS to the chiller control panel termination point.

B. The interface shall provide monitoring of information normally available at the chiller control panel, the ability to change manual settings normally made at the chiller control panel, as well as the ability to change settings automatically, such as chilled water temperature reset, demand limiting, etc.

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2.7 SOURCE QUALITY CONTROL

A. Notify the NPS at least 3 days in advance of tests to allow Representative(s) to witness the tests.

B. Completely assemble the compressor at the factory, and hydrostatically tested either before or after assembly of shaft and rotor. After assembly, pressure-test the compressor with a mixture of refrigerant and air, and test the casing, joints and connections with an electronic refrigerant detector.

C. Conduct performance tests on the refrigeration machine in accordance with ARI 550 at the manufacturer’s factory under 100 percent, 75 percent, 50 percent and 25 percent load conditions to check performance capacity and efficiency, vibration, operating controls, and safety cutouts.

D. Pressure Test Requirements: The cooler waterside shall be hydrostatically tested at 225 psi gauge for a working pressure of 150 psi gauge, and the condenser waterside shall be hydrostatically tested at 225 psi gauge for a working pressure of 150 psi (1 035 kPa) gauge. The refrigerant side shall be tested at 1-1/2 times the working pressure.

E. If the equipment fails to perform within the tolerances set forth in ARI 550, correct the problem and retest at no additional cost to the University. If the machine still fails to perform, the University will reject the refrigeration machine.

F. Submit a certified test report confirming performance as specified.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Install chiller package on concrete foundations, sole plates and sub-base. Align, level, grout, and bolt in place.

B. Arrange piping for easy dismantling to permit tube cleaning.

C. Provide auxiliary water piping necessary for oil-cooling units and purge condensers.

D. Refrigerant Piping: Provide refrigerant hot-gas and liquid piping for remote condenser units in accordance with the manufacturer's requirements and the drawings.

E. Provide pressure-relief discharge piping from relief valve to outdoors. Provide stainless-steel flexible connector at the refrigeration machine as detailed on the drawings. Discharge shall be at least 15 feet above grade, and 20 feet away from building opening. Provide size recommended by chiller manufacturer, terminated with gooseneck facing down.

F. If no factory-mounted oil cooler chilled-water-piping circuit is provided, provide field piping in accordance with manufacturing recommendations, including valves, filters and drains.

G. Connect purge-unit discharge piping into main system pressure-relief piping upstream of flexible connector.

H. Before units are started, pump new grease into bearing housing to force out old grease and provide adequate lubrication.

3.2 FIELD QUALITY CONTROL

A. Manufacturer’s Field Services:

1. Provide service of a factory-trained service engineer to supervise testing, evacuation, hydration, charging of unit, and start-up; make necessary adjustments; and instruct the University’s operator on the care, operation and maintenance of the system.

2. Provide five 8-hour days of service for the first unit, and two 8-hour days for each additional unit.

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B. Notify the University at least 24 hours in advance of field tests to allow University Representative to witness the tests.

C. Operational Control Tests:

1. Demonstrate proper functioning of the entire operational control of the chiller. Verify proper operation as specified in part 2 of this section, including oil pumps, liquid-line solenoid valves, crankcase heaters, thermal-expansion valves, chilled-water and condenser water flow switches, and adjustable temperature controllers.

2. Demonstrate chiller capacity control by varying the chiller load. The capacity range to be tested shall be from no-load to full-load and back to no-load. The chiller shall demonstrate stable operation without excess vibration or noise. Verify each step of the multi-step control (cylinder unloading and/or compressor staging).

D. Safety Control Tests:

1. Demonstrate proper functioning of safety cutouts in accordance with safety control requirements of part 2 of this section.

2. Demonstrate that manual resetting is required to restart compressors for safety cutouts.

3. Demonstrate proper operation of interlocking between chillers and condenser-water pumps, and between chillers and chilled-water pumps.

4. Simulate variables to activate safety control actions.

5. All safety control tests shall be verified by electric signals at the compressor motor starters or actual stopping of the compressors.

E. Running and Warning Indicators Test:

1. Demonstrate proper functioning of indicating lights.

2. Testing of running and warning indicators may be performed concurrently with safety control tests.

F. Site Tests:

1. Pressure Test: After assembly of the complete unit on the job, pressure test the unit with a mixture of refrigerant and air, and test connections and welds with an electronic leak-detector torch and make refrigerant-tight. The complete unit shall be dehydrated by producing a vacuum to 0.3 inch Hg absolute and maintained for four hours. At the end of this period, stop the pump. The vacuum shall be maintained in the refrigeration unit for a period of 24 hours without gaining more than 0.1 inch Hg absolute pressure.

2. Provide sufficient refrigerant and dry nitrogen for pressure testing under manufacturer’s supervision.

3. Provide instruments required for conducting tests.

3.3 DEMONSTRATION

A. Schedule operation and maintenance instruction period with the University Representative. Submit operation and maintenance manuals in advance of instruction period.

END OF SECTION 236427