Atch 2 - REVISED Salient Characteristics 16 SEP.pdf

Salient Characteristics for Data Center CRAC & Chiller Replacement

1. General Scope This document outlines the salient characteristics and minimum requirements for the procurement, delivery, and installation of replacement Computer Room Air Conditioning (CRAC) units and the supporting outdoor Air-Cooled Chillers for the Data Center. The new equipment must meet or exceed the performance, capacity, footprint, and efficiency metrics of the legacy equipment as detailed in the facility’s as-built schedules.

The systems operate as an integrated chilled water loop where the outdoor chillers supply chilled water directly to the indoor CRAC units to maintain precise environmental conditions within the critical data center whitespace.

2. CRAC Equipment Overview The indoor mechanical replacement includes six (6) downflow Chilled Water (CHW) CRAC units currently servicing the data center.

• Equipment Tags: CRAC-01, CRAC-02, CRAC-03, CRAC-04, CRAC-05, and CRAC-

• Cooling Method: Chilled Water (CHILL WTR)

• Airflow Configuration: Downflow (for raised-floor distribution)

• Location: Indoor Data Center

2.1. CRAC Mechanical & Fan Specifications

• Fan Type: Air Foil Plug Fan (or modern equivalent high-efficiency, direct-drive

Electronically Commutated [EC] fans)

• Drive Type: Direct Drive (to minimize maintenance and belt-shedding particulates in the white space)

• Motor Capacity: Up to 15.00 HP (must match or exceed legacy CFM and static pressure requirements)

• External Static Pressure (ESP): Designed for a minimum of 0.75 in. w.g.

2.2. CRAC Cooling & Performance Capacities

Replacement CRAC units must support the varying airflow and cooling load profiles defined by the existing design baseline:

Unit Designation

Total Airflow

(CFM)

Entering Air Temp

(DB / WB /

RH)

Chilled Water Flow

(GPM)

Min. Total Capacity

(MBH)

Min.

Sensible Capacity

(MBH)

CRAC-01 17,500 72°F / 60°F

/ 50%

75.0 352.0 310.8

CRAC-02 19,500 72°F / 60°F

/ 50%

75.0 352.0 310.8

CRAC-03 16,000 72°F / 60°F

/ 50%

75.0 352.0 310.8

CRAC-04 17,500 72°F / 60°F

/ 50%

75.0 352.0 310.8

CRAC-05 9,000 67.4°F /

57.8°F / 50%

15.0 214.8 90.0

CRAC-06 9,000 67.4°F /

57.8°F / 50%

15.0 214.8 90.0

Chilled Water Coil Performance (Baseline):

• Entering Chilled Water Temperature: Ranging from 44.0°F to 54.4°F (depending on loop conditions)

• Maximum Air Pressure Drop Across Coil: 0.4 in. w.g.

2.3. CRAC Filtration Requirements

• Filter Type: High-capacity Pleated

• Efficiency Rating: MERV 8 minimum (providing at least 70% dust spot efficiency)

• Maximum Initial Pressure Drop: 0.23 in. w.g. @ 500 FPM

3. Chiller Equipment Overview The outdoor utility replacement includes two (2) high-efficiency, air-cooled, packaged scroll chillers operating in a parallel N+1 redundant configuration to supply the indoor CRAC loop.

• Equipment Tags: CH-1 and CH-2

• Cooling Method: Air-Cooled Condenser Coils (utilizing environmentally friendly approved low-GWP refrigerants)

• Compressor Type: Hermetic Scroll (featuring multiple compressors per unit or digital scroll unloading to match partial load swings)

• Location: Outdoor Ground Pad / Chiller Yard

3.1. Chiller Performance & Capacity Specs

Each chiller must meet or exceed the performance capabilities of the legacy 115-Ton baseline units and accommodate existing outdoor pad limitations without structural yard expansions:

• Minimum Capacity (Tons): 115Tons at design ambient conditions

• Design Outdoor Ambient Temperature: 110.0°F

• Chilled Water Flow Rate (GPM): 233.3 GPM per chiller

• Leaving Chilled Water Temperature (LVT): 44.0°F

• Entering Chilled Water Temperature (ENT): ~51.7°F to 52.0°F (yielding a design Delta T of approx. 7.7°F)

• Maximum Evaporator Pressure Drop: 21.2 ft wg (approx. 9.2 psi)

• Minimum Part-Load Efficiency (IPLV): 15.3 EER or better

3.2. Chiller Mechanical & Condenser Specifications

• Condenser Coils: All-aluminum microchannel (MCHX) technology to reduce overall refrigerant charge and operating weight. Coils must feature protective corrosion-resistant e-coat encapsulation to ensure durability in outdoor environments.

• Condenser Fans: Direct-drive, low-sound composite AeroAcoustic vertical discharge fans with protective wire safety guards.

• Integrated Condensate Pump Assembly: Each CRAC unit must include an internal, factory-wired and plumbed condensate pump rated for a minimum of at total dynamic head (at with integrated spring-loaded discharge check valve).

• Dual-Float Safety Interlocking: Sump includes primary operational float switch and secondary high-water safety overflow float switch.

• • Dual-Float Safety Interlocking (Leak Detectors): Sump includes primary operational float switch and secondary high-water safety overflow float switch.

On high-water detection, the unit controller shall instantly: Force the chilled water modulating valve completely closed. Shut off the steam humidifier and electric reheat.

• Annunciate an audible and visual "HIGH CONDENSATE WATER LEVEL" fault on the local display. De-energize summary alarm contacts to trip external warning indicators.

• Steam Generator Humidifier: Self-contained electric electrode steam cylinder humidifier with auto-flush cycle and field-replaceable disposable cylinders.

Modulating steam output: (). Automatic water-level monitoring and auto-flush conductivity management to prevent mineral scaling.

• Low-Ambient Operation: Standard operation down to –20°F ambient (requiring integrated head-pressure fan controls and factory-installed wind baffles) to support winter-time data center cooling loads.

• Evaporator: Single-pass, brazed plate direct expansion heat exchanger constructed of ANSI 316 stainless steel, insulated with 3/4-in. closed-cell foam and wrapped with factory freeze protection heaters down to -20°F.

4. Electrical Requirements (All Equipment) All indoor and outdoor mechanical systems must be fully compatible with the facility's existing electrical infrastructure:

• Operating Voltage: 460 V AC

• Phase/Frequency: 3 Phase / 60 Hz

• Power Connection: Single-point electrical connection at each unit-mounted terminal block or integrated non-fused disconnect switch.

• Chiller Safety Locks: Electrical components must have high short-circuit current ratings (minimum SCCR of 65 kA) to protect internal motor circuits.

5. Piping, Hydronics & Loop Infrastructure The mechanical contractor must align replacement piping and accessories with the parallel N+1 as-built hydraulic schematic:

• Common Chilled Water Header Flow: Sized for a combined maximum design flow of 466.0 GPM.

• Piping Material: Type-L seamless copper tubing or schedule 40 carbon steel piping with Victaulic-style mechanical couplings to isolate structural vibrations.

• Air Separator: Inline centrifugal-type air separator with automatic air vents installed at the system's highest and warmest return points to prevent loop cavitation.

• Expansion Tank: Diaphragm-type expansion tank, pre-charged and rated for a maximum system working pressure of 150 psig, located on the suction side of the pumps.

• Water Filtration: A 40-mesh Y-strainer with an integrated blow-down ball valve must be installed at each chiller's evaporator inlet.

6. Self-Contained Controls Architecture The control system for both the chillers and the indoor CRAC units is entirely self-contained and stand-alone. The installation does not connect to a centralized Building Management System (BMS). All staging, failover, safety interlocking, and diagnostics must be handled autonomously by unit-mounted microprocessors and hardwired field interlocks.

Stand-Alone Chiller Plant Automation

• Lead/Lag Master-Slave Interlink: Chillers CH-1 and CH-2 must feature factory-integrated, autonomous master/slave sequencing controls via dedicated communication cabling between the two chillers (peer-to-peer without central supervisory controller).

• Automatic Lead Rotation & Equalization: The stand-alone controller shall automatically equalize run hours across compressors and chillers based on configurable operating hour thresholds.

• Autonomous Auto-Failover: In the event of a fault, loss of flow, or power failure on the lead chiller, the lag chiller shall automatically start and ramp up to full capacity without manual intervention.

• Loop Temperature Control: Internal microprocessors shall modulate capacity (staging scroll compressors and electronic expansion valves) based solely on the integrated leaving chilled water temperature sensors.

• Local Human-Machine Interface (HMI): Each chiller must be equipped with an exterior weatherproof, backlit display screen providing:

• Direct local adjustment of chilled water setpoints and schedule.

• Real-time display of entering/leaving water temperatures, suction/discharge pressures, and motor operating hours.

• Onboard diagnostic alarm history storing at least the last 25 fault events with timestamp data.

Stand-Alone CRAC Unit Controls

• Unit-Mounted Microprocessor: Each CRAC unit must feature an independent, factory-programmed digital microprocessor controller mounted inside the unit casing.

• Local Interface Display: Door-mounted full-graphic touchscreen or backlit LCD display allowing local technicians to:

• Configure temperature and humidity setpoints independently.

• View real-time return air temperature, supply air temperature, and chilled water valve position.

• Access diagnostic menus, run-time counters, and alarm history logs.

7. Footprint & Site Coordination

• Indoor Footprint Constraints: CRAC replacement units must fit entirely within the structural limits of the existing Bravo 2000 floor grid (24" x 24" floor panel dimensions, 18" raised floor height).

• Outdoor Pad Clearances: Chillers must fit on the existing concrete equipment pad while maintaining National Electrical Code (NEC) clearances (minimum 4.0 ft clearance on electrical panel doors and 3.5 ft to 6.0 ft airflow clearance around condenser coils).

• Modifications to the equipment pad, isolation rails, and piping transitions required to fit the new units are within the contractor's scope, provided the overall pad dimensions are not exceeded.

7. Footprint & Site Coordination