The document describes the YORK® YZ Centrifugal Chiller, an engineering guide (Form: 161.01-EG1, 0618) for a magnetic bearing centrifugal chiller.
Function Description
The YORK® YZ Centrifugal Chiller is a factory-packaged unit designed for cooling applications. It integrates a compressor, motor, variable speed drive (VSD), OptiView™ control center, evaporator, condenser, and purge unit, along with all necessary interconnecting piping and wiring. This chiller is optimized for ultimate performance, utilizing a next-generation low-GWP (global warming potential) refrigerant (R-1233zd) to deliver superior real-world performance and sustainability. It's designed to operate efficiently under various conditions, including part-load and full-load with reduced entering condenser water temperatures (ECWTs), aiming for lower operating costs and a high return on investment.
Important Technical Specifications
Capacity and Refrigerant:
- Cooling Capacity: 580 through 3500 kW (165 through 1000 Tons).
- Refrigerant: R-1233zd.
Compressor:
- Type: Single-stage centrifugal design, directly driven by a hermetically-sealed motor with a VSD.
- Impeller: Cast-aluminum, fully-shrouded, mounted directly to the motor shaft.
- Impeller Seals: Labyrinth geometry, sized for minimal thrust loading.
- Balance: Dynamically balanced and overspeed tested.
Motor:
- Type: Hermetically-sealed, high-speed induction motor.
- Bearings: Active magnetic bearings for lubrication-free operation, with mechanical bearings as backup for emergency touchdown situations.
- Cooling: Motor rotor and stator cooled by a pressure-driven refrigerant loop.
- Power Failure: Magnetic bearings remain operational during compressor coast-down using an uninterruptable power supply.
Variable Speed Drive (VSD):
- Mounting: Factory-packaged and mounted on the chiller in a NEMA-1/IP22 enclosure.
- Function: Varies compressor motor speed by controlling frequency and voltage.
- Power Factor Correction: Automatic displacement power factor correction to 0.95 or better (0.98 or better with optional harmonic filter).
- Start-up: Soft start with input current less than full load current.
- Protection: Door interlocked lockable circuit breaker, UL/cUL listed and CE approved ground fault protection, over-voltage and under-voltage protection, 3-phase sensing motor over-current protection, single-phase protection, insensitive to phase rotation, over-temperature protection.
- Power Connection: Single-point power connection with a circuit breaker disconnect.
Heat Exchangers (Evaporator and Condenser):
- Shells: Fabricated from rolled carbon steel plates with fusion welded seams or carbon steel pipe. Carbon steel tube sheets welded to ends. Intermediate tube supports from carbon steel plates.
- Refrigerant Side Design: Designed, tested, and stamped in accordance with local pressure vessel codes.
- Tubes: Copper alloy, high-efficiency, externally and internally enhanced, with "skip-fin" design for extra wall thickness at support locations. Expanded into tube sheets for leak-proof seal. Individually replaceable.
- Evaporator: Patented hybrid falling-film type, balancing flooded and falling-film technology. Features a spray header for uniform refrigerant distribution and a suction eliminator.
- Condenser: Shell and tube type with a discharge gas baffle and integral subcooler.
- Liquid Level Sight Glass: 38 mm (1.5") located on the side of both evaporator and condenser shells.
- Refrigerant Relief Valves: Dual relief valves on condenser and evaporator (or two single relief valves on evaporator with optional isolation valves).
- Refrigerant Charging Valve: 25.4 mm (1") on evaporator.
Waterboxes:
- Material: Fabricated of steel with integral steel water baffles.
- Connections: Stub-out water nozzle connections suitable for ANSI/AWWA C-606 couplings, welding, or flanged. Plugged 19 mm (3/4") drain and vent connections.
- Design Working Pressure: Standard 1034 kPa (150 psig) DWP; optional 2070 kPa (300 psig) DWP.
Water Flow Switches:
- Type: Thermal or differential pressure.
- Mounting: Factory mounted in evaporator and condenser water nozzles, wired to OptiView™ control panel.
Refrigerant Flow Control:
- System: YORK® variable orifice control system.
- Function: Continuously monitors liquid refrigerant level and electronically adjusts to optimize subcooler, condenser, and evaporator performance.
Refrigerant Purge Unit:
- Compliance: ASHRAE Standard 147 (at most one unit mass of refrigerant purged per one unit mass of air removed).
- Type: Automatic, self-contained, high-efficiency.
- Monitoring: Purge exhaust cycles monitored for potential system leaks.
Isolation Mounting:
- Standard: Four vibration isolation mounts (nominal 25.4 mm / 1" operating height) with neoprene pads.
- Optional: Level-adjusting, spring-type vibration isolator assemblies (25.4 mm / 1" deflection) for field-installation.
Voltage Variations:
- 60 Hz: Rated 460V (Min 414V, Max 508V), 400V (Min 360V, Max 440V), 380V (Min 342V, Max 423V).
- 50 Hz: Rated 415V (Min 374V, Max 456V), 400V (Min 360V, Max 440V), 380V (Min 342V, Max 423V).
Shipping Weights (Maximum, without refrigerant):
- FB2910/CA2110: 5950 kg (13100 lb)
- FB2912/SA2512: 7650 kg (16850 lb)
- FA3312/SA2512: 8600 kg (18300 lb)
- FA3312/CA2512: 8850 kg (19500 lb)
- FA3314/SA3314: 10900 kg (24000 lb)
- FA3914/SA3314: 11750 kg (25900 lb)
- FA3914/CA3314: 12800 kg (28200 lb)
- FA3916/SA3916: 16050 kg (35350 lb)
- FB4816/SA3916: 18250 kg (40250 lb)
- FB4816/CA3916: 20100 kg (44350 lb)
- FB4818/SA4418: 23000 kg (50700 lb)
- FB5618/SA4418: 25450 kg (56100 lb)
Usage Features
Efficiency and Performance:
- Real-World Efficiency: Designed for continuous operation with cold ECWT and full condenser flow, optimizing performance under off-design conditions (up to 99% of operating time).
- Improved Efficiency: Up to 7% better at part-load and an additional 5% at full-load compared to previous designs.
- Capacity Control: Fully modulating control from 100% to 10% of design capacity without hot gas bypass (HGBP), using variable speed control and mechanical flow regulation. Automatically adjusts to maintain constant leaving chilled liquid temperature at optimized efficiency.
- Operating Range: Expanded operating range and improved performance through patented combination of hardware and software.
- IPLV/NPLV: Information standardized within AHRI Certification Program.
Control System (OptiView™ Control Center):
- Type: Factory mounted, wired, and tested microprocessor-based control system.
- Interface: Full screen graphic display with keypad and soft keys.
- Monitoring: Monitors chiller operation, sensors, actuators, relays, and switches. Continuously monitors system operation, records shutdowns (safety, cycling, normal), and provides status/warning messages.
- Capacity Control: Controls leaving chilled liquid temperature and adjusts motor current via Variable Geometry Diffuser (VGD) and VSD.
- Data Display: Graphical representation of historical and present operation. Displays information in SI and Imperial units, and supports multiple languages.
- Security: Three levels of access and passwords to prevent unauthorized changes.
- Networking: Common networking protocol through Building Automation System (BAS) for increased remote control, 24-hour performance monitoring, and compatibility with existing BAS communications.
- EMS Interface: Supports Remote Start, Remote Stop, Remote leaving chilled liquid temperature setpoint adjustment, Remote current limit setpoint adjustment, Pulse Width Modulation, Remote "Ready to Start" Contacts, Safety Shutdown Contacts, and Cycling Shutdown Contacts.
Refrigerant Containment:
- Design: Factory-packaged to minimize joints and leaks.
- Testing: Thoroughly leak tested at the factory.
- Service Valves: Conveniently located for refrigerant transfer to a remote storage/recycling system.
- Optional Isolation Valves: Factory-installed in compressor discharge and refrigerant liquid lines for isolating and storing refrigerant charge in the condenser.
Multiple Unit Arrangements:
- Parallel Arrangement: Chillers connected in parallel for both chilled and condenser water circuits. Units load and unload at equal percentages of design full load.
- Series/Parallel Arrangement: Chilled water circuits in series, condenser water circuits in parallel. All chilled water flows through both evaporators.
- Series Counter Flow Arrangement: Chilled water circuits in series, condenser water in series counter flow. All water flows through both evaporators and condensers.
Application Data:
- Location: Virtually vibration-free, can be located at any level in a building with sufficient support. Requires a level mounting pad or foundation (within 6.5 mm / 1/4").
- Clearance: Sufficient clearance for service and maintenance, especially at one end for tube cleaning.
- Indoor Installation: Operating temperatures from 4.4°C to 40.0°C (40°F to 104°F). Dew point temperature in equipment room must be below entering condenser water temperature.
- Water Flow Rates: Evaporator: 0.91m/s to 3.66m/s (3.0 fps to 12.0 fps). Condenser: 1.0m/s to 3.66m/s (3.3 fps to 12.0 fps). Two-pass units limited to 134kPa (45ft H2O) water pressure drop; three-pass units limited to 201kPa (67.5ft H2O).
- Variable Primary Flow (VPF): Operates successfully in VPF systems with minimum allowable evaporator tube velocity of 0.5m/s (1.5 fps).
- Water Temperature Ranges: Leaving chilled water temperatures from 3.5°C (38°F) to 21.0°C (70°F). Temperature deltas from 1.7°C to 16.7°C (3°F to 30°F).
- General Piping: Chilled water and condenser water pumps should discharge through the chiller. Piping should include offsets for flexibility, prevent drainage when pumps shut off, and be adequately supported independently of the chiller. Isolators in piping and hangers are desirable.
- Chilled Water Strainer: Maximum 3.2 mm (1/8") perforated holes, field-installed in the chilled water inlet line.
Maintenance Features
Serviceability:
- Field Serviceable: Designed for field serviceability by Johnson Controls service team.
- Installation: Designed to keep installation costs low, with minimal piping and wiring required for complete packaged units.
- Start-up: Requires supervision or performance by a Johnson Controls factory-trained field service representative for final leak testing, charging, initial start-up, and operator instructions.
Reliability:
- Durable Design: Based on successful YORK® compressor lines with fewer moving parts.
- Frictionless Operation: Active magnetic-bearing drive provides 80% fewer moving parts than oil-lubricated or refrigerant-lubricated systems.
- Component Testing: Majority of chiller components time-tested on tens of thousands of air-cooled and water-cooled YORK® chillers globally.
Certifications and Standards:
- AHRI Certification: Performance certified by Air Conditioning, Heating and Refrigeration Institute (AHRI) to Standard 550/590. Regularly tested for independent, third-party verification.
- Performance & Energy Standards: ASHRAE 90.1, AHRI Standard 550/590, IECC, GBCI, Eurovent (EN14511, EN14825), GB 18430.1, GB 19577/GB 50189, GB/T 50378, MEPS, ECBC, Greenmark.
- Sound Ratings: AHRI 575, ISO 9614/3744, JB/T 4330.
- Pressure Vessel Codes: ASME Boiler and Pressure Vessel Code – Section VII – Division I, PED, NB/T 47012, KHK.
- Electrical Codes: c/U.L., N.E.C., CE – Directive 93/68/EEC, IP, GB 5226.1, ETL.
- Safety Codes: ASHRAE 15, ASME, EN 378-2/A2, Machinery Directive (2006/42/EC), EMC Directive (2004/108/EC), EN 60204-1, GB 25131.
- Manufacturing Requirements: Manufactured in an EN ISO 9001 accredited organization, conform to CE Testing Services, EN 61000-6-2:2005 and EN 61000-6-4:2007 compliance.
Factory Testing:
- Johnson Controls offers factory performance testing for all chiller types, including performance, vibration, and sound. Can be performed as factory or remote customer witness tests.
Smart Equipment and Connected Chillers:
- Smart Equipment: Connects data streams to the cloud for insights into operations, maximizing system control, extending equipment life, and reducing operating costs.
- Smart Connected Chillers: Feeds YZ chiller data to a secure, cloud-based dashboard for historical data analysis, diagnosis, long-term trend observation, and issue investigation. Detects problems like tube fouling or low refrigerant charge. Enables proactive maintenance.
Convenience Considerations:
- Vent and Drain Valves: Evaporator and condenser waterboxes equipped with plugged vent and drain connections; optional field installation of valves and piping.
- Pressure Gauges: Optional installation of pressure gauges with stop-cocks and stop-valves in condenser and chilled water lines.
- Overhead Monorail/Beam: Can be used to facilitate servicing.
Thermal Insulation:
- Optional Factory Insulation: Prevents condensation on cold surfaces in environments with dry bulb temperatures of 10.0°C to 32.2°C (50°F to 90°F) and relative humidity up to 75% (19 mm / 3/4" thickness), 85% (25.4 mm / 1" thickness), or 90% (38 mm / 1.5" thickness). Designed for indoor installations.
- Removable Insulation: If applied to waterboxes at the job site, it must be removable for tube access.
Water Quality:
- Requires analysis by a water treatment specialist to prevent corrosion, scale, sedimentation, or organic growth. Corrective water treatment and periodic tube cleaning are recommended.
Refrigerant Relief Piping:
- Vent line must run from relief device to outside of building, include a cleanable, vertical leg dirt trap, and be arranged to avoid strain on the relief connection (flexible connection recommended).
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