15601_en.doc

SECTION 15601

CENTRAL REFRIGERATION EQUIPMENT FOR AIR CONDITIONING

PART 1 - GENERAL

1.1

APPLICABLE PUBLICATIONS

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

Air Conditioning and Refrigeration Institute (ARI) Publication

590-86 Reciprocating Water-Chilling Packages.

Italian Superior Institute for Accident Prevention and Safety at Work (ISPESL)

D.P.R 27 April 1955 No.547

European Standardization Committee (CENELEC) Publication

Document 11.74 European Norms for Motors.

International Electrotechnical Committee (IEC) Publication

IEC 72, 72A

Dimensions and Output Ratings for Rotating Electric Machines

Italian National Institute for the Unification of Standards (UNI) Publications

UNI 8011

(1979+1982) Refrigerating Plants. Safety Requirements.

UNI 8199

(1998) Acoustics - Acoustic Test of Air Conditioning and Ventilating Systems - Contract Guide Lines and Method of Measurements.

UNI 5634

(1997) Identification Systems for Pipelines and Canalizations Conveying Fluids.

1.2

RELATED REQUIREMENTS

The provisions of Section 15050, “Basic Mechanical Materials and Methods”, apply to this section.

1.2.1 Qualification of Manufacturer and of Installation

Upon request, the Contractor shall furnish proof that he is complying with the paragraphs titled "Service Record" and "Installation" below.

1.2.2 Service Record

The Contractor shall furnish only products of a manufacturer, which are of a similar material, design, and workmanship as has been in satisfactory field operation in a similar application for a period of 2 years. Products having less than a 2-year field service record will be acceptable if a certified record of satisfactory field operation for not less than 6000 hours can be shown. In either case, modifications to the equipment which have satisfied the field operation record will be permitted only when proven that the modifications will not increase maintenance or operating costs or decrease product life, and provided that such modifications do not accomplish any of the following:

a.

Increase rotative speed in excess of 20 percent;

b.

Reduce metal thickness in section subject to high pressures or vacuum;

c.

Change lubricating system or bearing;

d.

Change refrigerant;

e.

Decrease in the design of surface area of condensers or evaporators of package water chillers.

1.2.3 Installation

The Contractor shall assure that all installation is carried out under the direct active supervision of persons who have adequate technical qualifications and experience, and that a sufficient number of trained personnel and adequate facilities are available to perform the installation.

1.3

CORROSION PREVENTION

Equipment shall have a zinc coating or a duplex coating of zinc and paint.

1.4

ELECTRIC MOTORS

Furnish motors with their respective pieces of equipment. See Section 16402, "Interior Distribution Systems" for controllers, contactors and disconnects. Motors shall conform to and shall have electric connections provided under Section 16402, "Interior Distribution Systems."

1.5

SAFETY REQUIREMENTS

1.5.1 Machinery Guards

Fully guard drive mechanisms or other moving parts. Provide guards fabricated of steel and expanded metal rigidly mounted, and readily removed without disassembly.

1.6

SPECIAL TOOLS

If any part of equipment furnished under these specifications requires a special tool for assembly, adjustment, setting, or maintenance thereof and such tool is not readily available on commercial tool market, it shall be furnished with equipment as a standard accessory. Special tools are those a refrigeration mechanic would not normally own.

1.7

MANUFACTURER'S SUPERVISION

Provide the services of competent factory representatives to supervise the installation, test, start-up, and adjustment of water chillers and pumps, and to instruct Government personnel in the proper operation and maintenance of the equipment.

1.8

SUBMITTALS

1.8.1 Manufacturer's Data

Chiller

1.8.2 Shop Drawings:

1.8.3 Operation and Maintenance Manuals:

1.8.4 Posted Operating Instructions:

PART 2 - PRODUCTS

2.1

REFRIGERATION MACHINE

2.1.1 General Requirements

Refrigeration Machine: Use materials in construction of refrigerating machines suitable for purpose intended. Materials coming in contact with refrigerant shall be highly resistant to corrosion by the refrigerant. Equipment shall operate within standard operating range and speed recommended by manufacturer, and rating for a particular machine shall not be less than that shown in manufacturer's latest catalog information. The refrigerating machine and connected system shall be charged with refrigerant and lubricating oil. Construct and provide refrigerant-containing apparatus with safety devices. Refrigerant safety relief devices shall consist of a safety relief valve in accordance with ISPESL. For chiller furnish and deliver to the Contracting Officer’s Technical Representative one complete charge of lubricating oil in sealed containers in addition to that placed in systems. Parts weighing 25 kilograms (50 pounds) or more which must be removed for inspection, cleaning, or repair such as motors, condenser and cooler heads shall be provided with lifting eyes or lugs. The unit's input energy requirements shall not exceed 0.34 kW/kW of refrigeration. Sound, vibration and seismic criteria are specified in Section 15070, "Mechanical Sound, Vibration, and Seismic Control."

2.1.2 Air-Cooled Water Chiller

Provide single package unit factory assembled, designed, tested, and rated in accordance with ARI 590 with air-cooled condenser. Unit shall use environmentally safe refrigerants as per Montreal Protocol for "CFC-FREE" (R 407c) refrigerants. Provide not less than two independent refrigerant circuits for multicompressor units. Provide direct expansion shell and tube design, refrigerant circuits, including electric-motor-driven refrigerant compressors with integral crankcase heater, heat tape for all water containing portions subject to freezing, air-cooled condenser, receiver, chiller, piping, controls, and accessories mounted in a cabinet. Provide refrigerant, internal pressure relief device, solenoid valve, combination liquid-line strainer-drier, expansion valve, and service valves. Condenser discharge air shall be in vertical direction. Provide guards to protect fins from mechanical damage. Crankcase heaters are not required when scroll compressors, 8 seconds time delay, and discharge thermostats are provided. Rotary screw water chillers will not be considered for this project.

Controls: Provide factory-wired controls including adjustable thermostat for chilled water temperature control, high-low pressure control, low water temperature safety thermostat, ON-OFF unit switch, and nonrecycling pump-down relay. Controls shall interface with building system controls. Controls shall also include maximum operating pressure expansion valves and programming of microprocessor chiller controls or high temperature controller for operation of compressors in cool down mode for start-up or changeover when entering water temperature is in 15 to 32 degrees C range. Provide electrical interlock between water chiller and chilled water pump to prevent chiller from operating unless pump is running. Provide flow switch or flow sensors in chilled water return piping to stop compressor in event of water flow failure. Condenser fan electric motors shall be drip-proof, with built-in three-phase overload protection, mounted inside the casing. Compressor motor stoppage due to thermal and pressure overload shall require manual restart. Provide reduced voltage starting to limit inrush current. Coordinate with controls and electrical service provided. Provide control and interlock wiring. Provide thermostat controlled electric heater cable around Dx cooler and exterior piping for freeze protection down to -18 degrees C air temperature, to operate when ambient exterior air temperature falls below 4 degrees C. Provide low ambient head pressure control and hot-gas bypass.

b.

Chiller Control:

1.

General: Control panel shall provide chiller plant control. The control panel shall be factory programmed and require only minimal configuration at the job site. The chiller sequencing shall incorporate the following features and control strategies.

2.

Piping System: The sequencing panel shall support a single pump for the chiller.

3.

System Enable: System shall be capable of starting by all of the following: initiated by a time clock, by start/stop switch at unit, by the operator from the sequencing panel.

4.

Chiller Sequencing: On system startup, the chiller and associated pump are enabled.

On chiller shutdown, the associated shutdown pump shall remain on for at least one minute to provide machine protection.

5.

Setpoint Control: The system chilled water setpoint shall be adjustable through the control panel.

6.

Chilled Water Reset: The panel shall provide the option of either load based or ambient based chilled water reset.

7.

Display Adjustments: In addition to setup parameters, the user shall be able to view and edit the following system information though the panel display.

a.

System supply water temperature.

b.

System return water temperature.

c.

Active system setpoint.

d.

Chiller status (Auto/Manual) e.

System enable (Auto/Stop) c.

Weatherproof casing: Provide removable gasketed panels designed to exclude driving rain for access to compressors, motors, and controls.

2.1.3 Factory Supervision

2.1.3.1 Services of a factory-trained representative shall be provided for 2 working days. Representative shall advise on the following matters:

a.

Testing water-chilling units under loaded conditions. Complete check out of all operating and safety controls and devices.

b.

Starting machine and instructing a representative of the Government as to its proper care, operation, and instrumentation.

2.2

PUMPS

Section 15181, "Chilled Water and Hot Water Piping."

2.3

EXPANSION TANKS

2.4

PIPE AND PIPE SYSTEM

PART 3 - EXECUTION

3.1

INSTALLATION

Equipment and components shall be completely installed in a manner to ensure proper sequential operation of the equipment and its controls. Installation of equipment not covered herein or in manufacturer's instructions shall be as directed by manufacturer's representative. Chiller shall be mounted on the ground at indicated on drawings. Proper foundations for mounting of equipment, accessories, appurtenances, piping, and controls shall be provided, including but not limited to supports, vibration isolators, stands, guides, anchors, clamps, and brackets. Isolation units shall be selected and sized, based on load-bearing requirements and lowest frequency of vibration to be isolated in accordance with Section 15070, "Mechanical Sound, Vibration and Seismic Control." Anchor bolts and sleeves shall be set accurately using properly constructed templates. Anchor bolts shall be of adequate length and provided with welded-on plates on the head and embedded in the concrete. Equipment bases shall be leveled, using jacks or steel wedges, and neatly grouted in using a non-shrinking type of grouting mortar. Equipment shall be located so that working space is available for all necessary servicing such as shaft removal, disassembling compressor cylinders and pistons, replacing or adjusting drives, motors, or shaft seals, access to water heads and valves of shell and tube equipment, tube cleaning or replacement, access to automatic controls. Electric isolation shall be provided between dissimilar metals for the purpose of minimizing galvanic corrosion. Keep equipment thoroughly clean and free from all debris with all oil, dirt, and paint spots removed until final acceptance.

3.2

FIELD TESTS AND INSPECTIONS

3.2.1 Inspection

Materials, equipment, and the completed installation will be inspected by the Contracting Officer’s Technical Representative. All equipment, materials, or work rejected because of defects or non conformance with plans and specifications shall be replaced or corrected by the Contractor as directed at no additional cost to the Government.

3.2.2 Tests

All tests shall be performed and everything required for test shall be furnished by the Contractor. Defects disclosed by the test shall be corrected by the Contractor at no cost to the Government. Tests after installation and prior to acceptance shall be performed in the presence of the Contracting Officer’s Technical Representative and subject to his approval. Equipment and material certified as having been successfully tested by the manufacturer in accordance with referenced specifications and standard will not require retesting before installation. Equipment and materials not tested at the place of manufacture will be tested before or after installation, as applicable, where necessary to determine compliance with referenced specifications and standards. When available, Government will provide water and electric power for testing.

3.2.2.1 Tests of Water Chillers, Pumps

Shall conform to Section 15950, "HVAC Testing/Adjusting/Balancing” for maximum sound criteria. Sound criteria test and data shall be submitted for approval.

3.2.2.2 Start-Up and Operational Test

The refrigeration system shall be started up and initially operated under the supervision of the manufacturer's representative. During this time, the various strainers shall be periodically cleaned until no further accumulation of foreign material occurs. Care shall be exercised so that minimum loss of refrigerant occurs when strainers are cleaned. Safety and automatic control instruments shall be adjusted as necessary to place them in proper operation and sequence. Operational tests shall cover a period of not less than 5 days.

3.2.2.3 Performance Tests

Upon start-up, final leak testing, and proper adjustment of controls, the systems shall be performance-tested to demonstrate that it complies with the performance and capacity requirements of the specifications and plans. Provide a full load test for all units after at least 30 days of operation. Testing shall be accomplished when it is determined by the Contracting Officer’s Technical Representative to be hot enough to provide full load. The system shall be tested for not less than 8 hours during which time hourly readings shall be recorded. At the end of the test period, the readings shall be averaged and the average shall be considered to be the system performance. Typed tabulated data taken during performance tests that will indicate that systems will produce required capacity shall be provided as required by Section 15950, "HVAC Testing/Adjusting/Balancing “.

-- End of Section --

Section 15601

Section 15601