SECTION 23 8419 PACKAGED POOL DEHUMIDIFICATION AND

SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
PART 1 - GENERAL
1.01
SCOPE: This natatorium pool dehumidification system shall control humidity and provide
ventilation air. The system shall be capable of exhaust air with exhaust air energy recovery.
1.02
GENERAL: The DESERT AIRE Select Aire dehumidifier shall be a heavy-duty, commercial /
industrial grade, heat recovery dehumidification system. It is to be completely assembled and
factory tested. The unit must include the following minimum parts and components:
compressor(s), evaporator (dehumidifier) coil, full-capacity condenser (hot gas reheat) coil,
blower, blower motor, refrigeration valves, water-cooled condensers (optional), and electrical
controls.
A.
The unit shall be constructed with staged, dual refrigeration circuits. Single circuit
systems shall not be allowed. Each circuit shall contain a dehumidifier coil and a fullcapacity hot gas reheat coil that can be controlled to provide simultaneous or
independent heat rejection.
B.
Options: The system shall reject heat to the following additional condenser(s) with the
corresponding purpose:
1.
Reheat, Water, and Remote Condenser Ready (RWROC): (Circuit A and / or
Circuit B) This design combines all the heat sink options. Heat shall be directed
to one of the following; to the air on a call for air heat; to the water on a call for
water heat; to a remote condenser on a call for air cooling.
1.03
SUBMITTALS: Submit the following technical and performance data: dimensions, capacities
under all operating modes, data on all factory-supplied accessories, and warranty information.
Submit supporting technical and performance data of the basis of the system design with the bid
documents.
1.04
QUALITY AND SAFETY ASSURANCE: The complete unit shall be built and tested in the U.S.A.
All parts and components shall be UL, ETL or ETLc listed. The manufacturer of the
dehumidification system shall have a minimum of ten (10) years of experience in the production
of these systems, including local reference installations.
1.05
INSTALLATION AND OPERATION DATA: An Installation and Operation manual shall be
included with each unit, complete with the following minimum information: Start-up checklist,
service and maintenance instruction, air balancing instruction, operation and control details, and
power and control schematics.
PART 2 - PRODUCTS
2.01
ACCEPTABLE MANUFACTURERS:
A.
2.02
Desert Aire, Dectron, Pool Pak
UNIT DESCRIPTION
A.
Enclosure: The unit shall be fabricated per the following method; The base rails and
supports shall be 12-gauge galvanneal steel channels; corner posts and side posts shall
be formed of 16-gauge galvanneal steel; top panels and removable side panels shall be
16-gauge galvanneal steel. Removable panels with insert nut screw sites shall be
provided to allow easy access to all internal parts and components. The electrical control
23 8419.1 - 1
SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
box and switch panel shall be enclosed in a separate compartment, complete with a
hinged door.
B.
Paint and Finish: Prior to painting, all metal parts shall be pretreated to remove oils and
dirt and rinsed with an ionized solution. Painting shall be by a powder coat technique to
assure positive adherence with a high-impact finish. All sides of panels shall be painted
after manufacturing. The paint shall be High Yield Polyester. The paint shall be rated to
meet a minimum of 1,000-hour salt spray test (ASTM B117), have a minimum Direct
Impact Resistance of 160 in-lbs (ASTM D2794), have a minimum flexibility of ¼” Mandrel
(ASTM D522, Method B) and a minimum 1000-hour Humidity Resistance (ASTM D2247).
The unit color shall be light gray.
C.
Refrigeration System:
1.
Refrigerant: The system’s operating refrigerant shall be R-410A only.
D.
Compressors (18 to 30 HP): The compressors shall be a dual circuit, heavy-duty scrolltype. The circuits shall be staged. The compressor shall be equipped provided with
high- and low-pressure safety switches, with internal protection from overheating. The
compressor shall be externally vibration isolated. The use of semi-hermetic compressors
is not acceptable.
E.
Receiver: The unit shall include a refrigerant receiver with rotolock service valves. The
receiver shall be sized for full-system refrigerant capacity to allow system pump down,
and for operating at the highest efficiency over a wide range of load conditions
F.
Evaporator Dehumidifier Coils:
1.
Fins: Fins shall be die-formed, aluminum and shall be damage resistant.
Extruded fin collars provide maximum heat transfer. Fin spacing shall be 10 FPI
(fins per inch) maximum. The coil shall be a maximum of 38” in height to avoid
water carryover to the reheat coil and re-evaporation into the air stream.
2.
Tubes: Coils shall be fabricated from seamless drawn copper. The tubes shall
be hydraulically expanded into the fins to form a permanent metal-to-metal bond
for maximum heat transfer and stability. The coil shall be a minimum of eight (8)
rows deep. The use of an eight-row coil is needed to assure the maximum
moisture removal at all entering air conditions.
3.
The use of one (1) coil for dual circuits intertwined, or face split shall not be
acceptable.
4.
Each coil shall have its own drain pan.
5.
Testing: Coils shall be leak tested with 625 psig nitrogen.
G.
Refrigerant Condenser Coils:
1.
Air-Cooled Condenser (Reheat Coil):
a.
The reheat coil shall be positioned with a minimum of 8” clearance from
the DX coil to help prevent water re-evaporation.
b.
Fins shall be die–formed aluminum and shall be damage resistant. Fin
spacing shall be 12 FPI (fins per inch) maximum.
c.
Coils shall be fabricated from seamless drawn copper. The tubes shall
be hydraulically expanded into the fins to form a permanent metal–to–
metal bond for maximum heat transfer and stability. The coil shall be a
minimum of two (2) rows deep.
d.
Testing: Coils shall be leak tested with 625 psig nitrogen.
23 8419.1 - 2
SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
H.
Pool Water-Cooled Condenser:
1.
The dehumidifier’s Circuit A shall be equipped with a water-cooled condenser
that rejects heat to the pool and or spa water loop as scheduled.
2.
The condenser shall be tube-in-tube, cupronickel construction with CPVC stubouts.
3.
The type, size, and capacity of the water-cooled condenser shall be in
accordance with the unit schedule.
4.
Outdoor units shall have the condenser wrapped in insulation and heat traced.
The heat tracing shall be wired back to the control panel for an independent
120V power connection.
I.
Remote Air-Cooled Condenser: (Optional)
1.
The size and capacity shall be in accordance with the unit schedule. The system
shall be able to reject all the recovered heat (THR) from Circuit B to the outdoor
condenser.
2.
The unit shall be provided with a weatherproof electrical panel with factory
mounted door interrupt disconnect switch.
3.
The cabinet shall be painted galvanized steel. The sides shall be one-piece
construction. The unit shall be provided with lifting eyes located on the fan
discharge panel.
4.
The coil shall be constructed of copper tubing in a staggered design. Tubes shall
be hydraulically expanded into full-collared, plate-type aluminum fins. Coils shall
be factory leak-tested and sealed with caps.
5.
The fan motors shall be direct drive external rotor. All motors shall be factorywired with leads terminating in a weatherproof junction box located on the
outside of the unit cabinet..
6.
The fan diameter shall not exceed 30”. All units shall have a dynamically
balanced fan with aluminum blades and painted steel hubs.
7.
The fans shall be cycled based on internal head pressure on multiple fan units.
8.
Fan guards shall be heavy-gauge, closed-mesh steel wire with vinyl coating.
Guards shall be contoured for maximum rigidity.
9.
RC5 and RC8 Standard Series (Option): The condenser shall use a low 1100
RPM motor designed fan blade to produce 69dbA or less noise @ 3 meters in
accordance with AHRI Standard 370-2001.
J.
ElectroFin® E-Coating: (Optional): Coat the following coils with ElectroFin E-coating to
resist chemicals and corrosion. The coating shall be applied to the entire coil assembly.
1.
The coil shall be sealed, electro-statically charged, coated and baked. Fin
coating only applications shall not be accepted.
2.
(Optional) Evaporator coil, hot gas reheat coil, and any airside fluid auxiliary
heating coil shall be coated.
K.
Hot Water Coil: (Optional)
1.
The capacity shall be in accordance with the unit schedule.
2.
The coil shall be integral to the unit. No external duct mount coils are
acceptable.
3.
Fins: Fins shall be die-formed, aluminum and shall be damage resistant. Fin
spacing shall be 11-14 FPI.
4.
Tubes: Coil shall be fabricated from seamless drawn copper. The tubes shall be
hydraulically expanded into the fins to form a permanent metal-to-metal bond for
maximum heat transfer and stability.
5.
Coils shall be leak tested with 315 psig of nitrogen.
6.
The modulating or on/off control valve shall be provided and installed by the
mechanical contractor to meet the required flow rate and pressure drop listed in
the schedule.
23 8419.1 - 3
SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
2.03
UNIT LOCATION
A.
2.04
2.05
The unit shall be designed for a rooftop application with bottom return air connection and
schedule supply air connection. Unit to be mounted on structural steel.
VENTILATION AND EXHAUST AIR
A.
The unit shall include the Extended Air Select Aire™ Energy Recovery Ventilation Air and
Exhaust Assembly with up to 50% of the supply air volume for ventilation air with an
equivalent amount of exhaust air to provide a negative pressure in the space. Exact
amount of ventilation and exhaust air is as listed on the specification schedule.
B.
Extended Select-Aire™ with Auto Balancing Control: The integral control system shall
maintain the correct proportions of return air, supply air, exhaust air and ventilation air.
The system shall monitor the static pressure difference at three locations; the ventilation
air intake, evaporator coil and the zone vs ambient.
1.
By monitoring the pressure differential across the ventilation air orifice plate the
unit controller will modulate the ventilation air damper to ensure the correct
amount of ventilation air during occupied times. The amount of ventilation air can
be set through the unit controller.
2.
The system shall monitor the pressure differential across the evaporator coil and
shall modulate the evaporator by-pass damper to ensure the proper amount of
evaporator cfm therefore optimizing the moisture removal capacity of the system
at all times.
3.
The system shall monitor the pressure differential between the zone pressure
and the ambient pressure once the initial field air balance has been completed
and setup values entered into the controller. This shall vary the exhaust fan
volume via the fan motor VFD to help guarantee the negative pressure within the
space.
4.
The exhaust section includes a calibrated balance plate that allows the system to
automatically balance the volume of air between the cold and warm exhaust
based on the mode of operation.
SELECT-AIRE™ HEAT RECOVERY SYSTEM: (Optional) The unit shall be supplied with an
integral fresh air/exhaust air heat recovery system for the introduction of outside air, to comply
with ASHRAE Ventilation Standards 62.1-2010 and local health codes.
A.
The exhaust air can be exhausted either before or after the evaporator coil, providing the
ability to extract energy from the return air if heating is required. The control decision
shall be determined by the thermostat's heating and cooling set points.
B.
On a call for heating, it is desirable to extract as much heat as possible from the exhaust
air. Energy is recovered from the exhaust air by first passing it through the circuit “A”
evaporator coil in a cooling /heat pump operation. The cooled air is exhausted and the
“Heat Pump” energy plus the heat of rejection is returned to the air stream or water (as
required) as sensible heat. The minimum COP of this operation is 4.4.
C.
On a call for cooling, warm return air from the space is exhausted before the evaporator
coil when it is desirable to remove as much heat as possible from the building. The
refrigeration system serves to dehumidify and/or air condition the return air from the
space.
D.
Exhaust shall be achieved by a centrifugal blower, properly sized for all exhaust modes
listed in the unit schedule.
23 8419.1 - 4
SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
2.06
E.
The ventilation air is brought in through the integral plenum, and isolated from the
exhaust air. It shall include MERV 7, 2” thick, extended surface type filters and a
motorized, proportional modulating damper assembly.
F.
The warm exhaust, cold exhaust, and ventilation air dampers each shall be a motorized,
proportional modulating damper assembly. All dampers shall be "fail to close".
G.
In addition, a motorized, proportional modulating damper assembly shall be included
between the evaporator coils to ensure proper face velocity and system efficiency in all
modes of operation. (Occupied and Unoccupied,)
H.
The controller shall automatically adjust these dampers to maintain the specified flow
rates (R/A, O/A, and E/A) through the use of integral flow measurement devices.
I.
The Select-Aire heat recovery system shall use the "heat pump" principle to recover
energy on a call for heating by operating one of the dual refrigeration circuits in
conjunction with exhaust air.
ELECTRICAL CONTROL PANEL: The electrical control panel shall be easily accessible on one
side so that service can be performed from the side of the unit. It shall be of adequate size so as
to house all electrical controls and devices. The unit shall be provided with single point power
connection to serve controls, fans, and compressors, factory wired to the power connection lug
set. The electrical controls shall include low-voltage transformers to supply 24 VAC control
power, clearly labeled high- and low-voltage terminal strips, high- and low-pressure control (with
manual reset of the high-pressure cutout and automatic reset of low-pressure cutout), and an
anti-short cycling timer to protect against compressor cycling.
A.
2.07
Short Circuit Current Ratings (SCCR): The complete unit shall be rated in compliance
with NEC® 110.10 and UL 1995 at nameplate voltage maximum, when protected by
Class J, Class T or Class RK1 fusing. Electrical markings on the unit shall include, but
not limited to the MCA (Minimum Circuit Ampacity), the MOPD (Maximum Over-current
Protection Device) and the SSCR.
CONTROL SYSTEM:
A.
A digital control system shall be used to accurately and precisely control the DESERT
AIRE dehumidification system and the space environment. He controller shall have three
(3) levels of password protection.
B.
The controller shall provide precise system control and feature an easy-to-read display
which indicates actual operating and set-points. The display shall be remote mountable
up to 1,640 feet from the unit. The controller shall have a built-in occupancy timer.
1.
Relative Humidity Sensor: The unit shall include a relative humidity sensor to be
field-installed in the space or return air duct as specified.
2.
Aquastat: (Optional) The dehumidifier shall be provided with one aquastat per
pool or spa water condenser. The aquastat shall be installed by the mechanical
contractor in the main water loop upstream of the pool heater and dehumidifier;
constant water flow required across the aquastat.
C.
Airflow Switch: The dehumidifier shall be equipped with an airflow switch to prevent the
compressors from starting or operating on loss of airflow.
23 8419.1 - 5
SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
D.
Water Flow Switch: (Optional) The dehumidifier shall be equipped with one water flow
switch per water condenser. A water flow switch shall prevent condenser operation in the
event of loss of water flow. The unit shall be able to function normally in the
dehumidification mode when water flow is not present.
E.
BMS Compatibility The units controller shall have the following BMS compatibility:
F.
The unit’s controller shall be BACnet MS/TP compatible.
1.
The following Control Points shall be available as read/write through the on board
terminal or through the BMS system:
a. Zone Air RH Setpoint
b. Zone Air RH Deadband
c. Zone Air Temperature Setpoint
d. Zone Cooling Deadband
e. Zone Cooling Stage Deadband
f. Zone Heating Deadband
g. Energy Recovery Deadband
h. Pool 1 Temperature Setpoint (optional)
i. Pool 1 Temperature Differential (optional)
j. Pool 1 Stage Deadband (optional)
k. Pool 2 Temperature Setpoint (optional)
l. Pool 2 Temperature Differential (optional)
m. Pool 2 Stage Deadband (optional)
n. Network Occupancy Command (optional)
o. Network Event Command (optional)
p. Network Purge Command (optional)
q. Network Off Command (optional)
r. Remote Reset
2.
The controller shall include the following alarms:
a. Low Suction Pressure Circuit A
b. Low Suction Pressure Circuit B
c. High Discharge Pressure Circuit A
d. High Discharge Pressure Circuit B
e. Supply Air Sensor Failure
f. Zone Air Sensor Failure
g. Supply Fan Overload
h. Compressor Circuit A Overload
i. Compressor Circuit B Overload
j. System Shutdown
k. Low Supply Air Temperature
l. Exhaust Fan Overload
m. Low Voltage (optional)
n. Low Air Flow
o. Freeze Stat (optional)
2.08
CONDENSATE DRAIN PAN: The drain pan shall be 20-gauge stainless steel, sloped, and
positioned under the dehumidifier coil. The drain pan shall be TIG welded and securely attached
to the evaporator endplates to avoid shifting. The drain pan shall be fitted with a minimum 1”
MPT non-corrosive plastic drain connection. The drain pan shall meet all the requirements of
ASHRAE Standard 62.
2.09
INSULATION: The thermal and sound insulation shall be engineered polymer closed-cell foam
insulation (EPFI). Indoor units shall have 3/8” thick insulation and outdoor units shall have 3/4”
thick insulation. The insulation meets the following requirements.
23 8419.1 - 6
SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
NFPA 255 Flame Spread - 25
NFPA 255 Smoke Developed - 50
NFPA 255 Fuel Contributed - 0
NFPA 90A (2-2.4.2) and 90B
ASTM C5118 (Thermal Resistance)
ASTM C411 (Hot Surface Performance)
ASTM C423 (Sound Absorption)
ASTM C665 ( Fungi Resistance)
ASTM E90 (Airborne Sound Trans. Loss)
ASTM E96 (Water Vapor Transmission)
UL 94HBF (Horizontal Burn)
UL 181 (Air Erosion, Mold Growth, and Humidity)
ASTM C1136 (Mold, Mildew, and Moisture Resistance)
2.10
BLOWER: The blower housing shall be made of galvanized steel and mounted on permanently
lubricated, sealed ball bearings. The blower assembly shall be a double inlet forward curved fan
for models 18 – 40 and double inlet backward curved fan for models 45 – 60. All fans shall be
dynamically and statically balanced.
A.
Blower Discharge: The unit’s air discharge shall be as shown on the drawing.
B.
Blower Pulley Assembly: The driver pulley and the blower pulley shall be made of cast
iron. The motor sheave shall be a variable pitch type to allow for field adjustment of CFM
and external static pressure, and be dynamically and statically balanced. The drive
overload service factor shall be 1.3 minimum.
2.11
RETURN AIR FILTERS: The system shall be provided with MERV 8 disposable filters consisting
of 4” pleated filter.
2.12
WARRANTY: The unit shall be manufactured of the finest quality components which are readily
available as off-the-shelf replacement parts throughout North America. All components shall be
warranted for a period of two (2) years from date of unit shipment. Although the warranty begins
on the date of shipment, the manufacturer shall not replace any component without a valid startup report on file. In addition, the manufacturer shall provide the following extended warranties:
A.
Provide an extended 3-year compressor warranty for a combined warranty of 5-years.
B.
Provide an extended 8-year warranty on airside coils with ElectroFin E-Coating for a
combined warranty of 10-years.
2.13
APPROVALS/LISTINGS: The unit shall be labeled and listed by ETL or UL.
2.14
UNIT MANUFACTURER: The unit shall be manufactured by DESERT AIRE CORPORATION,
Germantown, Wisconsin, U.S.A. The manufacture must be an active member of the AHRI
Dehumidification group.
2.15
MODES OF OPERATION: In the dehumidification process, energy is transferred from the room
air to the refrigerant as it passes through the evaporator coils. The air, having been cooled below
its dew point, shall condense moisture as it passes through the cold evaporator coil. The
resulting energy generated by this condensing process, along with the power consumption of the
compressor, is given up as sensible heat by the respective condensers (air reheat coils, water
heating condensers) to be distributed as required. The system shall introduce make-up air
between the evaporator coil and the hot gas reheat coil.
23 8419.1 - 7
SECTION 23 8419
PACKAGED POOL DEHUMIDIFICATION AND HEAT RECOVERY UNIT
A.
2.16
The system consists of dual, independent refrigeration circuits. These refrigeration
circuits can operate independently or simultaneously and are staged to match the loads
and maximize the energy recovery process by utilizing the appropriate “heat sinks.”
Compressor unloading shall not be accepted.
SEQUENCE OF OPERATION: The dehumidifier shall maintain its moisture removal capacity in
all modes of operation, as specified in the unit schedule. Controls shall automatically operate the
dehumidification heat recovery system in response to system requirements and adjust its output
to maintain specified conditions. The heat recovery unit shall be capable of rejecting the total
heat of rejection (THR) to the air for space heating (reheat), to a remote air-cooled outdoor
condenser on a call for air cooling.
A.
The dehumidifier shall maintain its moisture removal capacity in all modes of operation, as
specified in the unit schedule.
B.
Partial or undersized condensers that can only operate in “series” are not acceptable.
C.
Fluctuations in moisture removal capacity due to partially sized condensers are not
acceptable.
PART 3 - EXECUTION
3.01
PREPARATION: Installing contractor to provide all labor, refrigerant, and material required for a
complete installation. (Minimum 3 feet clearance on all sides.) Work to be performed shall be in
accord with local codes, regulations, and OSHA standards.
3.02
DELIVERY, STORAGE, AND HANDLING: Customer to provide a suitable space for the
equipment with proper access and entries. Unit to be stored in a clean, dry place and protected
from the outdoor environment. Handle with care to avoid damage.
3.03
INSTALLATION: Unit shall be installed per plans and manufacturer’s installation
recommendations.
3.04
FIELD QUALITY CONTROL: Installing contractor to clean, check, and perform all preliminary
start-up procedures before final operation of the unit, per manufacturer’s recommendations.
3.05
PROVIDE COMPLETE OPERATION/MAINTENANCE MANUALS (IN ENGLISH) AND
INCLUDE THE FOLLOWING MINIMUM LISTS: electrical and control drawings, and refrigeration
piping drawings. Manufacturer’s representative shall instruct owners/operators of the unit
regarding its functions and sequence of operation.
END OF SECTION
23 8419.1 - 8