Section 236500
Cooling Towers
	PART 1 GENERAL
1.01	SECTION INCLUDES
A.	Closed-circuit, forced-draft, counter-flow cooling towers with hybrid operation.
1.02	REFERENCE STANDARDS
A.	ASME B31.5 - Refrigeration Piping and Heat Transfer Components 2016.
B.	ASME Section VIII Boiler and Pressure Vessel Code
C.	ASTM B117 - Standard Practice for Operating Salt Spray (Fog) Apparatus 2018.
D.	ASHRAE Standard 90.1 - Energy Standard for Buildings Except Low-Rise Residential Buildings
E.	CTI ATC-105 - Acceptance Test Code 2000.
F.	CTI STD-201 OM - Operations Manual for Thermal Performance Certification of Evaporative Heat Rejection Equipment 2017.
G.	CTI STD-201 RS - Performance Rating of Evaporative Heat Rejection Equipment 2017.
H.	ISO 9001 - Quality management systems -- Requirements 2015.
I.	NEMA MG 1 - Motors and Generators 2017.
1.03	SUBMITTALS
A.	Product Data: Provide rated capacities, dimensions, weights and point loadings, accessories, required clearances, electrical requirements and wiring diagrams, and location and size of field connections. 
B.	Shop Drawings: Indicate suggested structural steel supports including dimensions, sizes, and locations for mounting bolt holes.
C.	Manufacturer's Certificate: Certify that cooling tower performance, based on CTI STD-201 meets or exceeds specified requirements and submit performance curve plotting leaving water temperature against wet bulb temperature.
D.	Manufacturer's Instructions: Submit manufacturer's complete installation instructions.
E.	Operation and Maintenance Data: Include start-up instructions, maintenance data, parts lists, controls, and accessories.
F.	Warranty: Submit manufacturer's warranty and ensure forms have been filled out in Owner's name and registered with manufacturer.
1.04	QUALITY ASSURANCE
A.	Manufacturer Qualifications:  Company specializing in manufacturing the type of products specified in this section, with minimum twenty years of documented experience and ISO 9001 certification.
B.	Installer Qualifications: Company specializing in performing the type of work specified in this section with minimum [_____] years of experience and approved by manufacturer.
C.	The Evaporative Heat Rejection Equipment shall comply with the energy efficiency requirements of ASHRAE Standard 90.1.  
1.05	REGULATORY REQUIREMENTS
A.	Products Requiring Electrical Connection: Listed and classified by Underwriters Laboratories Inc. as suitable for the purpose specified and indicated.
1.06	DELIVERY, STORAGE, AND HANDLING
A.	Factory assemble entire unit. For shipping, disassemble into as large as practical sub-assemblies so that minimum amount of field work is required for re-assembly.
B.	Comply with manufacturer's installation instructions for rigging, unloading, and transporting units.
1.07	WARRANTY
A.	One year warranty after start up, or eighteen months from date of shipment, whichever occurs first. Warranty to include coverage for defects in material and workmanship.
B.	Fans, fan motors, variable speed controller, bearings, sheaves, drive shafts, gears,  couplings, and mechanical equipment support must be warranted against defects in materials and workmanship for a period of five (5) years.
	PART 2 PRODUCTS
2.01	MANUFACTURERS
A.	Basis of Design: Baltimore Aircoil Company
B.	Closed-Circuit, Forced-Draft, Counter-Flow Cooling Towers with Hybrid Operation:
1.	Baltimore Aircoil Company; Nexus Modular Hybrid Cooler: www.baltimoreaircoil.com
2.02	MANUFACTURED UNITS
A.	Provide a modular hybrid, forced draft counterflow cooler. It must be provided with a full controls package that provides modes to optimize water and energy savings, and eliminate any potential for spray water system freezing in cold weather climates.  The entire unit and controls package shall be factory-wired and tested.  The controls will be integral to unit operation with single point power connection. Provide controls to allow for future system expansion. 
2.03	COMPONENTS
A.	Cold Water Basin:
1.	Provide type 304 stainless steel basin with drain/clean-out connection. Basins constructed of 301 stainless steel are not acceptable. 
1.	The spray water collection basin and all of its components and accessories will be fully accessible while the unit is in operation. Proper lockout-tagout procedures must be followed when servicing electrical components. The cold water basin is to be located at work bench height from base of unit to facilitate easy inspection and maintenance.
2.	Basin will allow no spray water to be exposed to sunlight. 
2.	Provide factory-installed collection basin accessories:
1.	Pan Strainer(s) will be all Type 304 Stainless Steel construction with large area removable perforated screens.
2.	Type 304 Stainless Steel Overflow connection
3.	Factory-wired and installed motorized large orifice drain valve
4.	Factory-wired and installed motorized make-up control water valves and Type 304 stainless steel connection
5.	Factory-wired and installed stainless steel high and low level alarms
6.	Factory-wired and installed water conductivity sensor
7.	304 Stainless steel threaded connection for water treatment system. 
3.	Provide a sloped collection basin that provides continuous turbulence of the water.  A factory-supplied solids separator and factory-installed basin sweeper piping system is an acceptable alternative. 
B.	Casing Panels and Framework:
1.	Casing panels: Galvanized steel protected by a thermosetting hybrid polymer. The polymer to consist of G-235 (Z700 metric) hot-dip galvanized steel prepared in a four-step (clean, pre-treat, rinse, and dry) process with an electrostatically applied, thermosetting, hybrid polymer fuse-bonded to the substrate during a thermally activated curing stage and monitored by a 23-step quality assurance program. Other coatings must be submitted to the engineer for pre-approval. Approved equals must have undergone testing, resulting in the following results as a minimum:
1.	When X-scribed to the steel substrate, unit to withstand 6000 hours of 5 percent salt spray per ASTM B117 without blistering, chipping, or loss of adhesion.
2.	When X-scribed to the steel substrate, unit to withstand 6000 hours of exposure to acidic (pH=4.0) and alkaline (pH=11.0) water solutions at 95 degrees F (35 degrees C) without signs of chemical attack.
3.	Unit to withstand impact of 160 in-lbs per ASTM D2794 without fracture or delamination of the polymer layer.
4.	Unit to withstand 6000 hours of ultraviolet radiation equivalent to 120,000 hours of noontime sun exposure without loss of functional properties.
5.	Unit to withstand 200 thermal shock cycles between minus 25 degrees F and 180 degrees F (minus 32 degrees C and 82 degrees C) without loss of adhesion or other deterioration.
6.	Unit to withstand 6000 hours of exposure to 60 psi (42,184 kg/m^2) water jet without signs of wear or erosion.
7.	Type 304 stainless steel may be supplied as an equal to eliminate the need for passivation, minimize maintenance requirements, and prolong equipment life.
----- ALTERNATE for 304 Stainless Steel -----
2.	Casing panels, framework, and fasteners will be constructed of Type 304 stainless steel. Type 301 stainless steel is not an acceptable alternative.
C.	Fans: Epoxy coated aluminum, radial type, with electronically commutated direct drive motors.
1.	Fan Coating: Comply with DIN EN 485-2.
2.	Factory installed and located outside of the wet airstream in the unit.
3.	Fan(s) must be constructed of an aluminum alloy designed to meet or exceed standard DIN EN 485-2, protected with an epoxy coating.
4.	Fan(s) must be both statically and dynamically balanced to provide for vibration-free performance.
5.	Provide fan plenum design with swing-out fan base with stainless steel hinge that allows for access and easy removal. For units with fans at the top of the unit, a davit assembly is to be provided for fan and motor maintenance and removal.
6.	Balancing: Fans will have maximum residual balance as per DIN ISO 1940.
D.	Motors and Drives:
Direct Drive System:
Electronically Commutated (EC) Drive system: Type F insulation with IP55 ingress protection. Full load efficiency of at least 91 percent, maintenance-free, permanently lubricated ball bearings, integrated thermal overload protection, PFC filter complying with IEC 61000-3-2, and integrated phase loss protection.

E.	Fan Guard: 304 Stainless steel wire mesh guards to prevent injury while fan is in operation.
F.	Heat Transfer System:
1.	Closed Circuit Heat Exchanger:
The heat exchanger will be constructed of a highly corrosion-resistant stainless steel alloy that exceeds accelerated cyclic corrosion test standard GMW14872. Type 316 stainless steel can be provided as equivalent.
1)	No field passivation required.
2)	Maximum allowable working pressure of 150 psi and tested according to UL1995.
3)	The heat exchanger shall provide a minimum efficiency of 1.0 nominal ton per 1.5 gallons of internal working fluid volume.
4)	Internal heat exchanger volume must not exceed volume listed on equipment schedule.
G.	Distribution Section: Polyvinyl chloride piping header and branches with ABS plastic spray nozzles.
H.	Drift Eliminators: Three pass PVC, drift loss limited to maximum of 0.005 percent of total water circulated.
I.	Basin Water Level Control: PVC, balanced piston type make-up valve with plastic float.
J.	Electronic Water Level Alarms: Must monitor and notify both high and low water levels. High and low alarm contacts included.  
K.	Hardware: Stainless steel nuts, bolts, washers, and tappers; assembled with phenolic epoxy coated, corrosion resistant washer head fasteners.
2.04	PERFORMANCE REQUIREMENTS
A.	This section is based on specific selections of equipment, and these selections relate to selection of related equipment. In substituting equipment, ensure that performance selection criteria matches that specified or that the selection of related equipment is acceptable or is revised to suit.
B.	Capacity:
1.	Water Flow: [_____] gpm ([_____] L/sec).
2.	Entering Water Temperature: [_____] degrees F ([_____] degrees C).
3.	Leaving Water Temperature: [_____] degrees F ([_____] degrees C).
4.	Entering Air WB Temperature: [_____] degrees F (______ degrees C).
5.	Ambient Air DB Temperature/Switchpoint: [_____] degrees F (______ degrees C).
C.	External Static Pressure: [_____] inch wg ([_____] Pa).
D.	Electrical Characteristics:
1.	[____] hp ([____] kW).
2.	[____] volts, single phase, 60 Hz.
3.	Disconnect Switch: Factory mount disconnect switch in control panel.
2.05	ACCESSORIES
A.	Water and Energy Conservation Control System: The closed circuit cooler control system will control all motor driven and optional electrically operated equipment including (but not limited to) the fan motor(s), pump motor(s), basin heater(s), vibration switch(es), damper actuators, conductivity controller(s), make-up and drain valve(s), and manufacturer supplied water level switches. The operation of all driven components must be manually overridden for equipment startup or troubleshooting. The status of all equipment must be available to be displayed on a panel mounted user interface.
1.	Design Requirements
1.	The control panel manufacturer shall be listed by Underwriters Laboratories as an approved manufacturer of industrial control panels. Use of commercial grade controllers from the building automation contractor shall not be acceptable. 
2.	The control panel enclosure shall meet NEMA 4x requirements.
3.	The closed circuit cooler control system shall have a Short Circuit Current Rating (SCCR) of a minimum of 65 kA at 460 VAC.
2.	Control Panel will include the following components: 
1.	Modbus and BACnet capabilities with 2-wire connection for Building Automation System (BAS) 
2.	Programmable Logic Controller (PLC) with 15 percent spare I/O terminals
3.	Fluid Outlet Temperature Sensor(s) [one per unit.] Refer to contract documents for quantity and location.
4.	Ambient Dry Bulb Sensor(s) [1 per unit.] Refer to contract documents for quantity and location. 
5.	Recirculating Pump Motor Starter(s)
6.	Main Circuit Breaker Disconnect 
7.	Control Power Transformer 
8.	High Basin Water Level Alarm Contact(s) 
9.	Low Basin Water Level Alarm Contact(s) 
10.	Relays, Fuses and Circuit Breakers for All Unit Equipment 
11.	UI Screen 
12.	Remote Access Device with cellular communication capability.  
13.	Relays
1)	Relays shall be of the plug-in base or terminal block type. Relays shall be rated for continuous duty operation. 
14.	User Interface (UI)
1)	Provide operator display as a stand-alone component with a separate programmable logic controller. Use of a computer for the process control will not be acceptable.
2)	The UI must be provided with a weather-tight cover mounted on the door of a NEMA 4 enclosure such that it will maintain the enclosure’s NEMA 4 rating.  
3)	The UI shall be industrially rated and certified for the following conditions:
(a)	Relative Humidity: 5 to 95% (Non-condensing) 
(b)	UI shall be rated for 50,000 hours of life 
(c)	The UI shall be industrially rated and certified for UL/ULC. 
3.	Operation
1.	The closed circuit cooler manufacturer shall furnish a description of the sequence of operation for the provided control system. 
2.	For all supported modes of operation, the panel shall utilize adaptive logic to allow for automatic adjustment between unit modes of operation based on real time system load and ambient temperature conditions. 
3.	Each unit shall be able to switch between the following unit modes of operation based on the customer set unit priority: 
1)	Energy Saving Mode – In this mode, the modular hybrid cooler shall operate with the basin water circulation pump(s) energized and the fan motor(s) running. The fan speed will be modulated based on real time leaving water temperature and ambient conditions for maximum energy efficiency. 
2)	Water Saver Mode – In Water Saver Mode, the modular hybrid cooler shall operate with the basin water circulation pump(s) de-energized and the fan motor(s) running. The fan speed shall be modulated based on real time leaving water temperature and ambient conditions for maximum water efficiency. 
3)	Balanced Water and Energy Saving Mode – In this mode, the individual modules will operate wet (circulating pump energized) or dry (circulating pump de-energized)  depending on the customer’s setting: 
(a)	Customer Priority Setting – While maintaining the desired process supply water temperature, the control system will automatically operate separate modules either wet or dry based on an integral sliding scale in the controls logic. The customer will have the ability to adjust their priority of energy or water savings by choosing a value on the sliding scale.
4.	Installation
1)	All wiring to the control panel shall be installed by a licensed electrician. The National Electrical Code and all applicable state and local codes shall be followed when installing this equipment. All power, control and sensor field wiring between the control panel and the closed circuit cooler must be provided by others. 
2)	Control panel enclosure must be mounted to the closed circuit cooler. Separate brackets or stands are not acceptable.  

B.	(Optional) UV System: A factory-supplied UV system will assist in the treatment of bacteria and other microorganisms. System will be shipped fully assembled and wired for fast installation. Only one system will be needed for each unit, regardless of number of modules. 
1.	The system will be housed in a steel enclosure manufactured with G-235 galvanized steel protected by a Thermosetting Hybrid Polymer OR 304 stainless steel. All piping will be constructed of PVC OR 304 stainless steel for non-combustible construction. 
2.	Overall system power consumption must not exceed 100W. 
3.	A 254nm UV lamp will be housed in a stainless steel disinfection chamber and provide at least 60mJ/cm2 dosage to the circulating water to limit bacterial growth. 
4.	The UV lamp must be easily changed without the use of tools. Bulb life must be at least one year of continuous operation. 
5.	Circulation pump will be brushless and seal-less spherical centrifugal type with ceramic bearing and 24VDC motor. Pump flowrate will be designed to circulate sufficient flow to properly treat spray water. 
6.	Water quality must be maintained according to manufacturer’s guidelines. 
7.	System must be able to be completely drained. An automatic solenoid drain valve must connect to factory-supplied controls to drain the UV system to avoid freezing or debris accumulation. 
8.	The UV system must be integrated into factory-supplied controls for seamless equipment operation. 
9.	Sensors must monitor for pump failure, low UV intensity, and loss of UV light. Alarms will alert user of any sensors reporting values outside of specified limits.  
10.	Wiring connections will be housed in a terminal box with at least a NEMA 4X rating. 

C.	(Optional) Electric Immersion Heaters: In pan suitable to maintain temperature of water in pan at 40 degrees F (4.4 degrees C) when outside temperature is 0 degrees F (-17.7 degrees C) or -20 degrees F (-28.9 degress C) and wind velocity is 15 mph (25 kph); immersion thermostat and float control operate heaters on low temperature when the pan is filled. Heaters will be constructed of copper.
D.	Access Packages: See submittal documents for access package requirements. Platforms and ladders must ship assembled from cooling tower manufacturer.
1.	The cold water collection basin and all of its components and accessories will be fully accessible while the unit is in operation. Proper lockout-tagout procedures must be followed when servicing electrical components. The cold water basin is to be located at work bench height from base of unit to facilitate easy inspection and maintenance.
2.	Drift eliminators will be accessible and removable from the side of the unit and will not require any fixed access platforms or ladders from the base of the unit.  Units that require drift eliminators to be removed from the top of the unit shall include access platforms, handrails, and ladders to facilitate maintenance of the drift eliminators.
E.	(OPTIONAL) External Process Fluid Piping on multi-module units:  
1.	Provide factory pre-piped powder coated black steel modular header assembly for all coil connections to allow for a single inlet and outlet connection for process fluid piping.  Headers shall be designed to allow for expected thermal expansion and contraction, while allowing for field misalignment.
2.	(Optional) Provide factory pre-piped stainless steel modular header assembly for all coil connections to allow for a single inlet and outlet connection for process fluid piping.  Headers shall be designed to allow for expected thermal expansion and contraction, while allowing for field misalignment.
	PART 3 EXECUTION
3.01	INSTALLATION
A.	Install in accordance with manufacturer's instructions.
B.	Provide the services of the manufacturer's field representative to supervise rigging, hoisting, and installation, allowing for minimum of ____ per tower.
C.	Install tower on structural steel beams or as instructed by manufacturer.
D.	Connect condenser water piping with flanged connections to tower. Pitch condenser water supply to tower and condenser water suction away from tower. Refer to Section 232113.
E.	Connect make-up water piping with flanged or union connections to tower. Pitch to tower. Refer to Section 221005.
F.	Connect overflow, bleed, and drain, to floor drain.
3.02	FIELD QUALITY CONTROL
A.	See Section 014000 - Quality Requirements, for additional requirements.
B.	Provide the services of the manufacturer's field representative to inspect tower after installation and submit report prior to start-up, verifying installation is in accordance with specifications and manufacturer's recommendations.
3.03	SYSTEM STARTUP
A.	Start-up tower in presence of and instruct Owner 's operating personnel.
3.04	SCHEDULES
A.	Cooling Towers
1.	Drawing Code:
2.	Location:
3.	Manufacturer:
4.	Model Number:
5.	Cooling Capacity
1.	Water Flow Rate:
2.	Entering Water Temperature:
3.	Leaving Water Temperature:
6.	Entering Air WB Temperature:
7.	External Static Pressure:
8.	Number of Fan Motors:
9.	Motor Size:
10.	Heaters No. and Type:
	END OF SECTION