237450.pdf

237450 - 1 VARIABLE REFRIGERANT

FLOW (VRF) SYSTEM

SECTION 237450 – VARIABLE REFRIGERANT FLOW (VRF) SYSTEM

GENERAL

1.1 RELATED DOCUMENTS

A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section.

1.2 ACTION SUBMITTALS

A. Product Data: For each type of product. Include rated capacities, operating characteristics, and furnished specialties and accessories.

1. Materials of construction, including casing construction details and finishes.

2. Wiring Diagrams: For power, signal, and control wiring.

1.3 BASIS OF DESIGN

A. The VRF system used as basis of design for this project and specified in the following sections is a Daikin Applied VRV-IV heat recovery system. Alternate systems may be substituted from the manufacturers listed in the following sections provided the materials of construction equal the basis of design, and the layout and scheduled performance is maintained. Final approval of substitutions will be determined by COR.

1.4 QUALITY ASSURANCE

A. The units shall be listed by Electrical Testing Laboratories (ETL) and bear the ETL label.

B. All wiring shall be in accordance with the National Electrical Code (N.E.C.).

C. The units shall be manufactured in a facility registered to ISO 9001 and ISO14001 which is a set of standards applying to environmental protection set by the International Standard Organization (ISO).

D. All units must meet or exceed the 2010 Federal minimum efficiency requirements and the proposed ASHRAE 90.1 efficiency requirements for VRF systems. Each combination shall be rated in accordance with Air Conditioning, Heating and Refrigeration Institute’s (AHRI) Standard 210/240 and bear the AHRI label.

E. A full charge of R-410A for the condensing unit only shall be provided in the condensing unit.

1.5 DELIVERY, STORAGE AND HANDLING

A. Unit shall be stored and handled according to the manufacturer’s recommendation.

1.6 WARRANTY

A. The units shall be covered by the manufacturer’s limited warranty for a minimum period of five (5) years from date of installation.

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B. In addition the compressor shall have a manufacturer’s limited warranty for a period of seven (7) years from date of installation.

C. The system shall be installed by a contractor with extensive install and service training.

The mandatory contractor service and install training should be performed by the manufacturer.

PRODUCTS

2.1 MANUFACTURERS

A. Daikin Applied

B. LG Electronics

C. Mitsubishi Electric

D. Trane

2.2 SYSTEM DESCRIPTION

A. Variable capacity, heat pump heat recovery air conditioning system VRF (Variable Refrigerant Flow) zoning system or approved equal.

B. The variable capacity, heat pump air conditioning system shall be a Daikin Variable Refrigerant Volume Series (heat/cool model) split system. The system shall consist of multiple evaporators using PID control, and Daikin VRVIV outdoor units as scheduled.

The outdoor units shall be direct expansion (DX), air-cooled heat pump air-conditioning system, inverter driven variable speed compressor, multi-zone split system, using R-410A refrigerant. The outdoor unit may connect an indoor evaporator capacity up to 130% to that of the outdoor condensing unit capacity. All indoor units are each capable of operating separately with individual temperature control

2.3 OUTDOOR UNIT

A. General:

1. The outdoor unit is designed specifically for use with VRF series components.

2. The outdoor unit shall be factory assembled and pre-wired with all necessary electronic and refrigerant controls. The refrigeration circuit of the condensing unit shall consist of a scroll compressor, motors, fans, condenser coil, electronic expansion valves, solenoid valves, 4-way valve, distribution headers, capillaries, filters, shut off valves, oil separator, service ports and suction line accumulator.

Liquid and suction lines must be individually insulated between the outdoor and indoor units

3. The outdoor unit can be wired and piped with outdoor unit access from the left, right, rear or bottom.

4. The connection ratio of indoor units to outdoor unit shall be permitted up to 130%.

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5. The sound pressure level standard shall be for the specified models at 3 feet from the front of the unit. The outdoor unit shall be capable of operating automatically at further reduced noise during night time.

6. The system will automatically restart operation after a power failure and will not cause any settings to be lost, thus eliminating the need for reprogramming.

7. The outdoor unit shall be modular in design and should allow for side-by-side installation with minimum spacing.

8. The following safety devices shall be included on the condensing unit; high pressure switch, low pressure sensor, control circuit fuses, crankcase heaters, fusible plug, overload relay, inverter overload protector, thermal protectors for compressor and fan motors, over current protection for the inverter and anti-recycling timers.

9. To ensure the liquid refrigerant does not flash when supplying to the various indoor unit units, the circuit shall be provided with a sub-cooling feature.

10. Oil recovery cycle shall be automatic occurring 2 hours after start of operation and then every 8 hours of operation.

11. The outdoor unit shall be capable of 100% heating operation at -10°F dry bulb ambient temperature and 70% heating operation at -20°F dry bulb ambient temperature.

B. Unit Cabinet:

1. The outdoor unit shall be completely weatherproof and corrosion resistant. The unit shall be constructed from rust-proofed mild steel panels coated with a baked enamel finish.

C. Fan:

1. The condensing unit shall consist of propeller type, direct-drive fan motors that have multiple speed operation via a DC (digitally commutating) inverter.

2. The fan motor shall have inherent protection and permanently lubricated bearings and be mounted.

3. The fan motor shall be provided with a fan guard to prevent contact with moving parts.

4. The outdoor unit shall be capable of operating at further reduced sound levels during night time.

D. Refrigerant

1. R410A refrigerant shall be required for outdoor unit systems.

E. Coil:

1. The condenser coil shall be manufactured from copper tubes expanded into aluminum fins to form a mechanical bond.

2. The heat exchanger coil shall be of a waffle louver fin and rifled bore tube design to ensure high efficiency performance.

3. The heat exchanger on the condensing units shall be manufactured from seamless copper tube with N-shape internal grooves mechanically bonded on to aluminum fins.

4. The fins are to be covered with an anti-corrosion acrylic resin and hydrophilic film.

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5. The pipe plates shall be treated with powdered polyester resin for corrosion prevention. The thickness of the coating must be between 2.0 to 3.0 microns.

F. Compressor:

1. Inverter scroll compressor shall be variable speed (PAM inverter) controlled which is capable of changing the speed to follow the variations in total cooling and heating load as determined by the suction gas pressure as measured in the condensing unit. In addition, samplings of evaporator and condenser temperatures shall be made so that the high/low pressures detected are read every 20 seconds and calculated. With each reading, the compressor capacity shall be controlled to eliminate deviation from target value.

2. The inverter driven compressor in each condensing unit shall be of highly efficient reluctance DC (digitally commutating), hermetically sealed scroll “G-type” with a maximum speed of 6,480 rpm.

3. Neodymium magnets shall be adopted in the rotor construction to yield a higher torque and efficiency in the compressor instead of the normal ferrite magnet type.

At complete stop of the compressor, the neodymium magnets will position the rotor into the optimum position for a low torque start.

4. The capacity control range shall be 24% to 100%.

5. The compressor shall be equipped with a crankcase heater, high pressure safety switch, and internal thermal overload protector.

6. Oil separators shall be standard with the equipment together with an intelligent oil management system.

7. The compressor shall be spring mounted to avoid the transmission of vibration.

G. Electrical:

1. The outdoor unit shall be controlled by integral microprocessors.

2. The control circuit between the indoor units, controller and the outdoor unit shall be completed using a 2-conductor, twisted pair shielded cable to provide total integration of the system.

2.4 FOUR-WAY CEILING CASSETTE UNIT (INDOOR UNIT)

A. General:

1. Indoor unit shall be a ceiling cassette fan coil unit, operable with R-410A refrigerant, equipped with an electronic expansion valve, for installation into the ceiling cavity equipped with an air panel grill. It shall be a four-way air distribution type, white, impact resistant with a washable decorative panel. The supply air is distributed via motorized louvers which can be horizontally and vertically adjusted from 0 degrees to 90 degrees. Computerized PD control shall be used to control superheat to deliver a comfortable room temperature condition. The unit shall be equipped with a programmed drying mechanism that dehumidifies while limiting changes in room temperature.

2. The indoor unit shall be completely factory assembled and tested. Included in the unit is factory wiring, piping, electronic proportional expansion valve, control circuit board, fan motor thermal protector, flare connections, condensate drain pan, condensate drain pump, condensate safety shutoff and alarm, self-diagnostics, auto-restart function, 3-minute fused time delay, and test run switch.

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3. Indoor unit and refrigerant pipes will be charged with dehydrated air prior to shipment from the factory.

4. Both refrigerant lines shall be insulated from the outdoor unit.

5. The 4-way supply air flow can be field modified to 3-way and 2-way airflow to accommodate various installation configurations including corner installations.

6. Return air shall be through the concentric panel, which includes a resin net mold resistant filter.

7. The indoor units shall be equipped with a condensate pan and condensate pump.

The condensate pump shall provide up to 21 inches of lift and shall have a built in safety shutoff and alarm.

8. The indoor units shall be equipped with a return air thermistor.

9. All electrical components are to be reached through the decorative panel, which will reduce required side service access.

B. Unit Cabinet:

1. The cabinet shall be located into the ceiling.

2. Three auto-swing positions shall be available to choose, which include standard, draft prevention and ceiling stain prevention.

3. The airflow of the unit shall have the ability to shut down one or two sides allowing for simpler corner installation.

4. Fresh air intake shall be possible by way of direct duct installation to the side of the indoor unit cabinet.

5. The cabinet shall be constructed with sound absorbing foamed polystyrene and polyethylene insulation.

C. Fan:

1. The fan shall be direct-drive turbo fan type with statically and dynamically balanced impeller with high and low fan speeds available.

2. The fan motor shall operate on 208/230 voles, 1 phase, 60 hertz with a motor output range from 0.06 to 0.12 HP.

3. The airflow rate shall be available in high and low settings.

4. The fan motor shall be thermally protected.

D. Filter:

1. The return air shall be filtered by means of a washable long-life filter with mildew proof resin.

E. Coil:

1. Coils shall be of the direct expansion type constructed from copper tubes expanded into aluminum fins to form a mechanical bond.

2. The coil shall be of a waffle louver fin and high heat exchange, rifles bore tube design to ensure highly efficient performance.

3. The coil shall be a 2-row cross fin copper evaporator coil with 17 FPI design completely factory tested.

4. The refrigerant connections shall be flare connections and the condensate will be 1-1/32 inch outside diameter PVC.

5. A condensate pan shall be located under the coil.

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6. A condensate pump with a 21 inch lift shall be located below the coil in the condensate pan with a built in safety alarm.

7. A thermistor will be located on the liquid and gas line.

F. Electrical:

1. A separate power supply will be required of 208/230 volts, 1 phase, 60 hertz. The acceptable voltage range shall be 187 to 253 volts.

2. Transmission (control) wiring between the indoor and outdoor unit shall be a maximum of 3,280 feet (total 6,560 feet)

3. Transmission (control) wiring between the indoor unit and remote controller shall be a maximum distance of 1,640 feet.

G. Control:

1. The unit shall have controls to perform input functions necessary to operate the system.

2. The unit shall be compatible with interfacing with a BMX system via BACnet gateways.

2.5 CEILING CONCEALED DUCTED UNIT (INDOOR UNIT)

A. General:

1. Indoor unit shall be a built-in ceiling concealed fan coil unit, operable with refrigerant R-410A, equipped with an electronic expansion valve, direct-drive DC (ECM) type fan with auto CFM adjustment at commissioning for installation into the ceiling cavity. It shall be a horizontal discharge air with horizontal return air configuration. All models feature a low height cabinet making them applicable to ceiling pockets that tend to be shallow. Computerized PID control shall be used to control superheat to deliver a comfortable room temperature condition. The unit shall be equipped with a programmed drying mechanism that dehumidifies while limiting changes in room temperature. A mildew-proof, polystyrene condensate drain pan and resin net mold resistant filter shall be included as standard equipment. The indoor units sound pressure shall range from 29 dB(A) to 43 dB(A) at low speed measured at 3.3 feet below and from the unit.

2. The unit shall be completely factory assembled and tested. Included in the unit is factory wiring, piping, electronic proportional expansion valve, control circuit board, fan motor thermal protector, flare connections, condensate drain pan, condensate drain pump, condensate safety shutoff and alar, self-diagnostics, auto-restart function, 3-minute fused time delay, and test run switch. The unit shall be equipped with automatically adjusting external static pressure logic that is selectable during commissioning. This adjusts the airflow based on the installed external static pressure.

3. Indoor unit and refrigerant pipes will be charged with dehydrated air prior to shipment from the factory.

4. Both refrigerant lines shall be insulated from the outdoor unit.

5. The indoor units shall be equipped with a condensate pan and condensate pump.

The condensate pump shall provide up to 18-3/8 inches of lift from the center of the drain outlet and shall have a built in safety shutoff and alarm.

6. The indoor units shall be equipped with a return air thermistor.

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B. Unit Cabinet:

1. The cabinet shall be located into the ceiling and ducted to the supply and return openings.

2. The cabinet shall be constructed with sound absorbing foamed polystyrene and polyethylene insulation.

C. Fan:

1. The fan shall be direct-drive DC (ECM) type fan, statically and dynamically balanced impeller with three fan speeds available.

2. The unit shall be equipment with automatically adjusting external static pressure logic selectable during commissioning.

3. The fan motor shall operate on 208/230 volts, 1 phase, 60 hertz with a motor output range of 0.12 to 0.47 HP respectively.

4. The airflow rate shall be available in three settings.

5. The fan motor shall be thermally protected.

6. The fan motor shall be equipped as standard with adjustable external static pressure (ESP) settings.

D. Coil:

1. Coils shall be of the direct expansion type constructed from copper tubes expanded into aluminum fins to form a mechanical bond.

2. The coil shall be of a waffle louver fin and high heat exchange, rifled bore tube design to ensure highly efficient performance.

3. The coil shall be a 3 row cross fin copper evaporator coil with 15 fpi design completely factory tested.

4. The refrigerant connections shall be flare connections and the condensate will be 1-1/4” outside diameter PVC.

5. A condensate pan shall be located under the coil.

6. A condensate pump with an 18-3/8” lift shall be located below the coil in the condensate pan with a built in safety alarm

7. A thermistor will be located on the liquid and gas line.

E. Electrical:

1. A separate power supply will be required of 208/230 volts, 1 phase, 60 hertz.

2. Transmission (control) wiring between the indoor and outdoor unit shall be a maximum of 3,280 feet (total 6,560 feet).

3. Transmission (control) wiring between the indoor unit and remote controller shall be a maximum distance of 1,640 feet

F. Controls:

1. The unit shall have controls to perform input functions necessary to operate the system.

2. The unit shall be compatible with interfacing with a BMS system via BACnet gateways.

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2.6 CONTROLS

A. The control system shall consist of a low voltage communication network of unitary built-in controllers with on-board communications and a web-based operator interface. A web controller with a network interface card shall gather data from this system and generate web pages accessible through a conventional web browser on each PC connected to the network. Operators shall be able to perform all normal operator functions through the web browser interface.

B. System controls and control components shall be installed in accordance with the manufacturer’s written installation instructions.

C. Provide capability for future system expansion to include monitoring and use of occupant card access, lighting control and general equipment control.

D. Control system shall fully integrate with the Building Automation System (BAS). Refer to specification sections 230900 “Instrumentation and Control for HVAC” and 230993 “Sequence of Operation for HVAC Control”.

2.7 BACnet INTERFACE

A. General:

1. The BACnet Interfaces shall be made from stainless steel. Each interface shall have a battery backup and LED lights to display status/error.

B. Electrical:

1. The BACnet Interface will require 24 VAC to power the unit. The Open Protocol Interface shall supply 16 volts DC to the communication bus on the terminal of the outdoor unit.

2. The Open Protocol Interface communication wiring shall be terminated in a daisy chain design at the outdoor unit, which is daisy chained to each indoor unit in the system and terminating at the farthest indoor unit. The termination of the wiring shall be non-polar. The remote control wiring shall run from the indoor unit control terminal block to the remote controller connected with that indoor unit.

3. Wiring shall be non-shielded, 2-conductor sheathed vinyl cord or cable and 18 AWG stranded copper wire.

C. Controls:

1. The Interface for use in BACnet shall provide the ability for a Building Management System (BMS) to control all indoor units. It shall be capable of controlling a maximum of 64 indoor unit groups (128 indoor units) connected to a maximum of 10 outdoor units.

2. The Interface for use in BACnet shall support operations superseding that of the Daikin centralized controller, local remote controller, system configuration, daily/weekly scheduling, monitoring of operation status, and malfunction monitoring.

3. The Interface for use in BACnet uses a standard open protocol based on ANSI/ASHREA Standard 135. The BACnet Interface has been certified by the

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BACnet Testing Laboratories (BTL). The BACnet Interface is compatible with BACnet IP (ISO16484-5).

4. The interface wiring shall consist of a non-polar two-wire connection to the terminals of the outdoor unit. The Interface for use in BACnet is wall mounted and is used as a translator between the BACnet Building Management System (BMS) and the VRF communication bus to maintain the optimal operation of the connected indoor unit(s).

5. The Interface for use in BACnet shall be equipped with one RJ-45 Ethernet port to support interconnection with a network PC via the Internet or Local Area Network (LAN). The Ethernet connection shall be capable of transmission on 10Base-T and/or 100Base-TX connection at 100 Mbps.

6. The Interface for use in BACnet shall be capable of being configured as a foreign device. It shall be capable of communicating across BACnet Broadcast Management Devices (BBMD) in different subnet networks.

7. The Interface for use in BACnet shall be capable of supporting Change of Value (COV) notification for all available objects.

D. Display:

1. The Interface for use in BACnet shall be approximately 10” x 10” in size.

2. LED display provides the interface’s operational status and alarm.

3. The Interface for use in BACnet shall be capable of displaying indoor unit objects on the BACnet building management system.

4. The Interface for use in BACnet shall provide the BACnet building management system the capability to command the setpoint temperature in 10F (0.10C) increments with a range of 600F - 900F (160C - 320C).

5. The Interface for use in BACnet shall provide the BACnet building management system the capability to display the room temperature in 0.10F (0.10C) increments with a range of -1200F - 1800F (-840C - 820C).

6. Error codes generated by the indoor units, outdoor units, branch selector boxes, and remote controllers shall be displayed on the BACnet building management system in the event of system abnormality/error with a two digit error code as specified by Daikin.

a. Communication errors between the Interface for use in BACnet and the BACnet building management system shall be displayed with a red flashing LED on the Interface for use in BACnet.

E. Basic Operation:

1. The Interface for use in BACnet will provide up to 28 objects that can be monitored/controlled via the BACnet building management system.

2. Capable of controlling up to 64 indoor unit groups (128 indoor units).

3. The Building Management System shall control the following group operations:

a. On/Off

b. Operation Mode (Cool, Heat, Fan, Auto, and Dry)

c. Single setpoint setting for Cooling and Heating in the occupied mode.

d. Fan status

e. Fan Speed

f. Up to 3 speeds (dependent upon indoor unit type)

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g. Vane direction (dependent upon indoor unit type)

h. 5 fixed positions or swing position

i. Remote controller permit/prohibit of On/Off, Mode, and Setpoint

j. Filter sign reset for indoor units

k. Disable the Intelligent Touch Controller

l. Forced off of indoor units

m. Forced Thermo-off of indoor units

n. Energy saving offset of indoor unit setpoint

o. Compressor status

p. Thermo-on status

q. Heater status

4. Capable of providing battery backup power for up to 3 years in total time for the clock.

a. Settings stored in non-volatile memory

F. Programmability:

1. The BACnet building management system shall support weekly schedule settings through its programming.

a. The schedule shall support the indoor unit:

1) On/Off

2) Each scheduled event shall specify time and target group

3) Each scheduled event shall include On/Off, Operation Mode, Occupied Cooling Setpoint, Occupied Heating Setpoint, Setup (Cooling) setback setpoint, Setback (Heating) setback setpoint, Remote Controller On/Off Permit/Prohibit, Remote Controller Mode Permit/Prohibit, Remote Controller Setpoint Permit/Prohibit, and Timed Override Enable

4) Setup (Cooling) and Setback (Heating) setpoints when unit is Off (unoccupied) by Group

5) An override shall be provided for use enabling indoor unit operation during the unoccupied period by the BACnet building management system programming.

2. The BACnet building management system shall support auto-changeover through its programming.

a. Auto-change shall provide changeover for both Heat Pump and Heat Recovery systems based upon the group configurations. This will allow for the optimal room temperature to be maintained by automatically switching the indoor unit’s mode between Cool and Heat in accordance with the room temperature and setpoint temperature.

b. Changeover shall change the operation mode of the indoor unit that is set as the Changeover Master. The Changeover Master indoor unit shall then change the operation mode of all indoor unit groups daisy chained on the same DIII-Net communication bus to the same outdoor unit in the Heat

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Pump system or the same branch selector box in the Heat Recovery system.

c. Changeover to cooling mode shall occur when the room temperature is great than or equal to the cooling setpoint

d. Differential to be determined by BACnet building management system programming

e. Changeover to heating mode shall occur when room temperature is less than or equal to the heating setpoint.

f. Differential to be determined by BACnet building management system programming

g. Guard timer

3. Upon changeover, guard timer will prevent another changeover during this period.

4. Guard timer should be ignored by a change of setpoint manually from the BMS, Intelligent Touch Controller, Remote Controller, or by schedule.

5. Guard timer to be configured by BACnet building management system programming (30 minute minimum recommended)

6. The Interface for use in BACnet shall support force shutdown of associated indoor unit groups

EXECUTION

3.1 INSTALLATION

A. Install units level and plumb.

B. Install indoor fan modules using manufacturer's standard mounting devices securely fastened to building structure.

C. Install ground-mounting, compressor-condenser components on 6-inch thick, reinforced concrete base; 6 inches larger on each side than unit. Concrete, reinforcement, and formwork are specified in Division 03. Coordinate anchor installation with concrete base.

3.2 CONNECTIONS

A. Piping installation requirements are specified in other Division 23 Sections. Drawings indicate general arrangement of piping, fittings, and specialties.

B. Install piping adjacent to unit to allow service and maintenance.

C. Ground equipment according to Division 26.

D. Electrical Connections: Comply with requirements in Division 26 Sections for power wiring, switches, and motor controls.

3.3 FIELD QUALITY CONTROL

A. Manufacturer's Field Service: Engage a factory-authorized service representative to inspect, test, and adjust field-assembled components and equipment installation, including connections. Report results in writing.

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B. Perform the following field tests and inspections and prepare test reports:

1. Leak Test: After installation, charge system and test for leaks. Repair leaks and retest until no leaks exist.

2. Operational Test: After electrical circuitry has been energized, start units to confirm proper motor rotation and unit operation.

3. Test and adjust controls and safeties. Replace damaged and malfunctioning controls and equipment.

C. Remove and replace malfunctioning units and retest as specified above.

3.4 STARTUP SERVICE

A. Engage a factory-authorized service representative to perform startup service.

1. Complete installation and startup checks according to manufacturer's written instructions.

3.5 DEMONSTRATION

A. Engage a factory-authorized service representative to train Government's maintenance personnel to adjust, operate, and maintain units. Refer to Division 01 Section "Demonstration and Training."

END OF SECTION 237450