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Modular Air Handling Units TECHNICAL CATALOGUE
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 1
Preface
About air handling units
The air handling unit (AHU) is one of the most essential and critical units to be considered when designing
an air conditioning system. Air T&D provides a wide range of AHUs for use in various applications from small
office premises to larger commercial and industrial applications.
Air T&D AHUs, with their plug-and-play design and inherent flexibility, can be configured and combined
specifically to meet the exact requirements of any building, no matter what it is used for or who is to work
there. Our systems are designed to be the most environmentally friendly and the most energy efficient on
the market. This means they have a reduced ecological impact, while, at the same time, keeping costs down
by minimizing energy consumption. When combined with the small physical footprint of the system, these
features make our AHUs ideal for all markets.
About this catalogue
This catalogue presents Air T&D’s standardized range of AHUs, which includes equipment for air flows
between 1,500 m3/h and 100,000 m3/h, with static pressures of up to 1000 Pa.
Special care has been taken in the preparation of the catalogue to ensure a user-friendly document. Only a
little effort is needed to obtain a rather precise overview of the air handling unit required, with clear, concise
information on the most important characteristics. Based on our experience, these are key data for the
start of any project.
Additional information can be used to identify each of the characteristics to be taken into account in the
precise, complete definition of each apparatus.
About Air T&D
Air T&D is incorporated in January 2015 in Singapore as a high-tech spinoff of Nanyang Technological
University. The company specializes in providing energy efficiency air treatment solutions. Through years
of research, our team has developed several cutting edge technologies, such as liquid desiccant based
dehumidification and air-conditioning systems, new comfortable and energy efficient air treatment
terminals - passive & active thermosiphon beams, etc. So far, we have more than 10 patents granted/filed
in the air treatment and distribution topics. The company focuses on providing sustainable solutions for the
air treatment and distribution of ACMV systems. Starting from Singapore, the company aims to be a major
player in ACMV area in Southeast Asia even all over the world.
Our mission, and the essence of our existence, is to identify and realize our customers’ future needs and
dreams, even those that they themselves may not yet be aware of. We can accomplish this goal by paying
careful attention to changes in social trends and conducting extensive marketing to win the hearts and
minds of customers. It is essential that we offer customers optimum convenience and comfort that are
always one step ahead of our competitors by providing customers with the highest quality products,
materials, and services for which we, as a manufacturer, will be absolutely responsible. Moreover, we will
continue offering products and services that provide customers with fresh excitement and continued
enjoyment.
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 2
Table of Contents
1. Features and Benefits ................................................................................................................................. 3
2. Configurations and Selections ..................................................................................................................... 6
2.1 Model Representation .......................................................................................................................... 6
2.2 Judgment of Left and Right Type .......................................................................................................... 6
2.3 Quick Model Selection .......................................................................................................................... 7
3. Components and Options ........................................................................................................................... 8
3.1 Diagram of Functional Sections ............................................................................................................ 8
3.2 Pressure Drop of Functional Sections ................................................................................................... 9
3.3 Combination of Commonly Used Function Sections ..........................................................................10
4. Specifications and Performances ..............................................................................................................13
4.1 Cooling Coil .........................................................................................................................................13
4.2 Heating Coil .........................................................................................................................................15
4.3 Filter ....................................................................................................................................................16
4.4 Fan/ EC Fan/ Fan Matrix Wall ..............................................................................................................19
4.5 Humidifier ...........................................................................................................................................22
4.6 Dehumidifier .......................................................................................................................................23
4.7 Energy Recovery Unit .......................................................................................................................24
4.8 Air Disinfector .....................................................................................................................................26
4.9 Electronic Dust Precipitator ................................................................................................................27
4.10 Activated Carbon Filter .....................................................................................................................27
4.11 Silencer..............................................................................................................................................28
5. Electrical and Automation System ............................................................................................................30
5.1 Electrical System .................................................................................................................................30
5.2 Automation System .............................................................................................................................32
6. Installation and Maintenance ...................................................................................................................35
6.1 Installation of Air Handling Unit ..........................................................................................................35
6.2 Usage and Maintenance .....................................................................................................................37
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Technological Innovation from NTU, Singapore 3
1. Features and Benefits
Superior Performance
High Quality
Designed For Maximum Flexibility
Industry-leading Energy Efficiency
System Optimization
Lower Installed Time and Cost
Low Noise Emissions
Casing Casings are made of aluminum frame with none cold bridge technology. The skeleton and double panel was
combined with special designed plywood. The casings have smooth inner surface, which can prevent
bacteria accumulation, and effectively improve pre-treated air quality. The casings are suitable for
applications with clean air requirements.
Panel
Panel is designed with none cold bridge double sandwich structure in which the standard configuration
of the outer layer is color steel plate, a n d the inner layer is high-quality galvanized steel filling with
polyurethane foam material of density of 48 kg/m3. The Panels can effectively prevent heat transfer. The
thicknesses of panels are manufactured to select in three nominal values: 25mm, 35mm, and 50mm.
Airtightness
Air tightness is achieved by double sealing between the skeleton and panel. The reliable and flexible sealing
material ensures good air tightness under either positive or negative pressure conditions.
Heat Exchanger
Cooling coil is made by seamless copper and aluminum fins. The copper tube and fins are sealed by 12MPa
hydraulic pipe expander, which ensures to minimize thermal contact resistance and maximize heat transfer
efficiency.
We provide four types of standard coil: 2 rows, 4 rows, 6 rows and 8 rows. The standard aluminum fin
spacing is 2.5mm. We can also tailor fin spacing upon user request.
The coil selection software can calculate parameters such as the number of rows, fin spacing, number of
loops so as to optimize the design to meet user's needs.
Drain Pan
A water tray is located underneath the cooling coil; it is designed to ensure smooth draining of condensed
water. The drain pan is coated with PE insulation layer.
Filter
The basic function of filter is to prevent the accumulation of dust on the internal surfaces of coils and panels,
extending the lifetime of the air handling unit. Three types of filters below are provided.
1) Primary Efficiency Filter: The filter material is an up-to-date polypropylene fiber, which
provides high dust-holding capacity and high filtration efficiency with lower resistance; it is an
ideal choice for pre-filter cell.
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 4
2) Medium Efficiency Bag Filer: It is made of new composite fiber material, with low resistance, high
dust-holding capacity and long life span. The bag filter has reasonable interior space dimensions
and allows the filter to achieve the lowest operating cost.
3) High Efficiency Filter: The filter material is ultra-fine glass fiber, which possess low resistance and
high efficiency characteristics. Filtration efficiency could be customized by to customer
demands; the filter configuration is strictly followed by the air velocity requirement, which
ensures the service life under normal operation.
Fan/ EC Fan/ Fan Matrix Wall
Three options are provided to follow the user demands:
1) Centrifugal fan: The fan uses double- inlet-double-width centrifugal type, with high efficiency
and low noise. The fan bearings are from the mainstream brands, which provide self-aligning
and self-locking functions. The accuracy of fan dynamic balance is G4.0, and it can significantly
extend the lifetime of bearings. Fan selection software can select the most efficient fan model
based on actual operating conditions to ensure the fan running in energy-efficient mode. The fan
is installed on a damping bracket, and connected with the casing through high-intensity and
flame-retardant flexible couplings.
2) "EC" (Electronically Commutated) Fan: The option for fans with brushless motors allows for units
with reduced dimensions. Controlled by means of a 0-10V signal even without a frequency
inverter, these fans are very versatile and easy to be used. The Air T&D AHU can be equipped
with EC motors by customer demand. The advantages for the manufacturer and end user include
superior integrated PID control, low noise and vibration, access to a wide range of operation
details, etc.
3) Fan Matrix Wall: It is a combination of smaller fans built into a wall section to replace a
traditional single large fan. This technology incorporates multiple direct-drive centrifugal plenum
fans, assembled in a rectangular array of four to 9+ fans, all discharging into a single plenum. The
fans used are specially designed and optimized for use. The use of multiple direct-drive fans
operating in parallel improves reliability by providing redundancy. Optimized fan wheel
construction and improved internal aerodynamics further enhance energy performance. The
advantages are the following: shorten the unit; quiet operation; energy savings through
optimized performance; redundancy; lower maintenance costs; and food for retrofits.
Fan Drive and Motor
For general Air T&D AHU with centrifugal fan, standard V-belt transmission structure is used, with Taper
Lock to confine the bush pulleys and narrow side of the V-belt. The wide ramp configuration of the narrow
side of V-belt allows it has a higher drive efficiency and higher service life than ordinary V-belt.
The squirrel-cage three-phase AC motor will be used in general structure, complying with IP Enclosure
Ratings, and F class motor insulation. Motor is placed inside the fan section, and placed on top of the
damper bracket through special damping pads, together with the fan. An adjustment device is in the bottom
of the motor, which allows easy adjustment of belt tightness.
Dehumidifier
Air T&D provides the most energy efficient Liquid Desiccant Dehumidification System (LDDS) and Liquid
Desiccant Air-Conditioning (LDAC) on the world market. Through the breakthrough on the design and
operation of LDDS & LDAC technologies, our products can achieve 30% to 50% energy savings when applied
to residential and commercial building HVAC systems.
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Technological Innovation from NTU, Singapore 5
Both LDDS &LDAC have been effectively integrated with various energy sources, including two-way heat
pump, chilled water and condensation heat in existing system, and combination of renewable energy and
grid power. Some key innovations are implemented, such as Energy Recovery, Vacuum Regeneration,
Intelligent Control, Hybrid and Distributed Operation, and Zero crossovers, etc., resulting in industry-leading
energy efficiency.
Automation System
Air T&D provides a complete BMS system, called “BSTAR”, with controller hardware, data acquisition tool,
HMI designer, and control function modules. BSATR can be used as perfect control solution of air handling
unit. Using this powerful platform, customers can design basic controls and some advanced functions for
Air T&D air handling units:
• Temperature control
• Frequency converter operation for constant air flow or duct pressure
• On-demand control
• Heating and cooling shunts
• CO2 compension control of fans
• Control of different types of heat exchanger
• Control of extra fans
• Control of temperature zones
• Communication via BACnet or Modbus
• Monitoring via a C/S or B/S interface
Rigging
There is a dual-use device provided at the bottom of the container box which allows flexible hoisting
for site conditions. The container segments could be separated into different parts and allows easy
shipping. The modular design allows easy replacements of AHU components, and makes on-site
installation process very convenient.
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Technological Innovation from NTU, Singapore 6
2. Configurations and Selections
2.1 Nomenclature
KDZ E 20 12 D W
1.
2. r
i
m
a
r
y
E
f
f
i
c
i
e
3.
Model Sample:
KDZE2012DW AHU:
Horizontal type; panel thickness is 25 mm; unit width is 20 mm; unit height is 12 mm.
Unit height = 12 X 100 + 25 X 2 + 80 = 1330 mm
Unit width = 20 X 100 + 25 X 2 = 2050 mm
Unit module and size calculation formula:
(1) Unit height = height index X 100 + panel thickness X 2 + base height
(2) Unit width = width index X 100 + panel thickness X 2
2.2 Judgment of Left-handed and Right-handed Type
Criterion
When the unit have chilled/hot water pipe,
o if the chilled/hot water pipe is at right side, and in the same direction as air flow,
the unit is known as right-handed type;
o Otherwise the unit is known as left-handed type.
When the unit does not have chilled/hot water pipe,
o if the access door is at right side, and in the same direction as airflow, the unit is
known as right-handed type;
o Otherwise the unit is known as left-handed type.
W: horizontal type, L: vertical type
Design serial number
Unit height index
Unit width index
Panel thickness: E=25mm, S=35mm, W=50mm
Modular Air Handling Unit
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Technological Innovation from NTU, Singapore 7
Air Intake
Air Supply
Remark
For Air T&D standard units, the access door, electrical wiring connection, and hot water pipe
are all located at the same side.
If customer has special requirements, please indicate them in the purchase order.
2.3 Quick Model Selection
Unit
Model
Nominal
Air Flow
(m3/h)
Air Velocity (m/s) Fan Impeller
Diameter (mm) 2 2.25 2.5 2.75 3 3.25 3.5
Air Flow (m3/h)
0606 1500 1230 1390 1540 1690 1850 2000 2150 180
0706 2000 1560 1750 1940 2140 2330 2530 2720 180
0906 3000 2200 2480 2750 3030 3300 3580 3860 200
0907 3500 2690 3030 3370 3700 4040 4380 4710 225
1007 4000 3090 3470 3860 4250 4630 5020 5410 225
1008 5000 3650 4110 4560 5020 5480 5930 6390 250
1208 6000 4590 5160 5730 6310 6880 7450 8030 280
1308 7000 5050 5690 6320 6590 7580 8210 8850 315
1309 8000 5830 6560 7290 8020 8750 9480 10210 315
1310 9000 6610 7440 8260 9090 9910 10740 11570 355
1410 10000 7220 8120 9030 9930 10830 11740 12640 355
1411 11000 8070 9080 10090 11100 12110 13120 14120 355
1511 12000 8760 9850 10940 12040 13130 14230 15320 400
1512 13000 9680 10890 12100 13310 14520 15720 16930 400
1712 15000 11190 12590 13990 15380 16780 18180 19580 450
2012 18000 13460 15140 16820 18500 20190 23950 25790 500
2013 20000 14740 16580 18420 20270 22110 23950 25790 500
2114 23000 16920 19040 21150 23270 25380 27500 29610 560
2314 25000 18720 21060 23400 25740 28080 30420 32760 560
2415 28000 21190 23840 26490 29140 31780 34430 37080 630
2416 30000 22760 25600 28450 31290 34140 36980 39830 630
2417 33000 23920 26910 29900 32890 35880 38870 41860 630
2418 35000 25910 29150 32390 35630 38870 42110 45350 710
2420 40000 28900 32520 34160 39740 43360 46970 50580 710
2621 45000 33190 37340 41490 45630 48780 53930 58080 800
2821 50000 35980 40470 44970 49470 53970 58460 62960 800
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Technological Innovation from NTU, Singapore 8
2823 55000 39520 44460 49390 54330 59270 64210 69150 800
2924 60000 42890 48250 53610 58970 64330 69690 75050 900
3026 65000 47660 53620 59580 65540 71490 77450 83410 900
3226 70000 51090 57480 63870 70250 76640 83020 89410 900
3228 75000 55180 62080 68970 75870 82770 89670 96560 1000
3428 80000 58880 66240 73600 80960 88320 95680 103040 1000
3430 90000 63240 71150 79060 86960 94870 102770 110680 1000
3632 100000 72630 81710 90790 99870 108950 118030 127100 1600
Note:
1. We suggest choosing unit type under air velocity of 2.75 m /s, and then determining unit size by the
nominal air flow.
2. When air velocity > 2.75 m/s, we suggest to install water demister in the unit.
3. If user requests for a nominal air flow greater than 100,000 m3/h, please contact us.
3. Components and Options
3.1 Diagram of Functional Sections
Functional
Section Diagram Remarks
Functional
Section
Name
Diagram Remarks
Mixing Section
When mixing section is followed by filer, access door needs to be added.
Wet film humidification section
Could be installed in cooling coil; need not to have independent section; it takes 600mm section to place separately.
Fresh/ Return/ Exhaust air section
High-pressure/ spray/ micro-fog humidifier
Provide drain pan; Could be placed beside cooling coil and share water Demister .
Plate type primary efficiency filer section
There should have inspection section before this section.
Fan section
Should have equally air distribution when air supply in middle section; Should have access door for inspection and maintenances.
Bag type primary/medium efficiency filer section
There should have inspection section before this section.
Fan section with diffuser
(均流段) Distribution section
Generally be placed behind the fan.
Cooling coil Section
Water Demister can be eliminated when wet film is placed after cooling coil.
Silencer
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Technological Innovation from NTU, Singapore 9
Hot water heating coil section
中间段
Generally used for inspection and maintenances
Steam heating coil section
Supply air section
Electrical heating section
Electrical heater should have interlocking control with the fan.
Plat Energy Recovery unit
Dry steam/ Electrode humidification section
Wheel Energy Recovery unit
Should leave some room for inspection and maintenances before and after this section
3.2 Pressure Drop of Functional Sections
Functional Section Pressure Drop (Pa) Functional Section Pressure Drop (Pa)
Mixing section 20 Steam heating section (1 row) 20
Cooling coil (2 rows) 40 Steam heating section (2 rows) 40
Cooling coil (4 rows) 80 Fresh air / return air / exhausted air
sections 20
Cooling coil (6 rows) 120 Silencer section 30
Cooling coil (8 rows) 160 Fan section with diffuser 20
Water Demister 60 Humidifier (60mm wet membrane) 25
Heating coil (1 row) 20 Humidifier (100mm wet membrane) 30
Heating coil (2 rows) 40 Humidifier (150mm wet membrane) 45
Heating coil (4 rows) 70 Humidifier (200mm wet membrane) 60
* The testing is under air velocity of 2.75 m /s.
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3.3 Combination of Commonly Used Function Sections
Section Combination 1: External Plate-type Filter + Cooling coil (Water Demister) + Fan
This is the most economic combination.
The combination 1 is allocated with the basic cooling coil and applied to general central air-conditioning
systems. It has the advantages with compact structures, small space occupation, and low investment.
Section Combination 2: Mixing + Plate-type Filter + Cooling coil (Water Demister) + Fan
It is the most economic combination with primary efficiency mixing air.
The combination 2 is allocated with the basic cooling coil and primary efficiency filter. It can handle fresh,
return, and mixing air, suitable for the temperature controlling requirements of the normal room. It has the
advantages such as compact structure and low cost.
Section Combination 3: Mixing Air + Plate-type Filter + Cooling coil (Water Demister) + Heating + Humidifying
+ Fan
It is most commonly used combination for air handling.
The combination 3 is allocated with the basic cooling coil, heater and humidifier, suitable for high
requirements of temperature and humidity control.
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 11
Section Combination 4: Mixing + Plate-type Filter + Cooling coil (Water Demister ) + Heating + Fan + Humidifying
+ Fan with Diffuser + Medium-Efficiency Filter + Air Supply
It is mainly used for purifying air.
The combination 4 is allocated with cooling coil, heater, humidifier and primary/ medium efficiency filter,
suitable for requirements of air purifying and temperature/humidity controlling.
Section Combination 5: Mixing + Primary/Medium Efficiency Filter + Cooling coil (Water demister) + Heating +
Humidifying + Fan + Diffuser + Silencer + Sub-high Efficiency Filter + Air Supply
It is used for high-purifying air-conditioning system.
The combination 5 is allocated with cooling coil, heater, humidifier and primary/medium efficiency filter,
suitable for requirements of air purifying, temperature, humidity and noise controlling.
Section Combination 6: (Top Layer) Air Supply + Medium Efficiency Filter + Middle Section; (Bottom Layer)
Mixing Air + Plate-type Filter + Cooling coil (Water Demister ) + Heating + Humidifying + Fan
The combination 6 is applied to the places which have the requirements of air purifying, temperature and
humidity controlling, and limited spaces.
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Technological Innovation from NTU, Singapore 12
Section Combination 7: (Top Layer) Fresh Air and Primary Efficiency + Plate-type Energy Recovery + Air Return
Primary Efficiency; (Bottom Layer) Ventilator + Plate-type Energy Recovery + Middle + Cooling coil (Water
demister) + Fan
It is an energy-saving air-conditioning system.
It is able to recover energy via ventilation, applied to the places which have small both Energy Recovery
and air flow.
Section Combination 8: (Top Layer) Air Return + Primary Efficiency Filter + Wheel Dehumidifier + Ventilation;
(Bottom Layer) Fan + Cooling coil (Water demister) + Middle + Wheel Dehumidifier + Primary Efficiency Filter
+ Fresh Air
It is an energy-saving air-conditioning system.
The combination is able to recover energy via ventilation, applied to the places which have large amount
of both Energy Recovery and air flow.
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Technological Innovation from NTU, Singapore 13
4. Specifications and Performances
4.1 Cooling Coil
User can select coils by accurate calculation from chilled water, hot water, steam and direct expansion types,
to provide optimum performance conditions. In accordance with system requirements, copper tube
aluminum fin or steel tube-steel fin coils are used in Air T&D air handling units. While copper tubes up to
2x105 Pa pressure is used in steam applications, the use of steel tubing is required for higher pressure steam
applications. Standard tube diameters used are 3/8”, 1/2” and 5/8”. In aluminum finned designs, fins are
coated with epoxy, providing high corrosion resistance.
Cooling Capacity and Water Flow VS Return Air Flow
Unit
Model
Nominal
Air Flow
(m3/h)
2 rows 4 rows 6 rows 8 rows
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
606 1500 4.7 0.8 8.6 1.5 11.5 2 13 2.2
706 2000 6.3 1.1 11.4 2 15.4 2.7 17.4 3
906 3000 9.4 1.6 17.1 3 23.1 4 26.1 4.5
907 3500 10.9 1.9 20 3.4 26.9 4.6 30.4 5.2
1007 4000 12.5 2.2 22.9 3.9 30.8 5.3 34.8 6
1008 5000 15.6 2.7 28.6 4.9 38.5 6.6 43.5 7.5
1208 6000 18.8 3.2 34.3 5.9 46.2 8 52.2 9
1308 7000 21.9 3.8 40 6.9 53.8 9.3 60.9 10.5
1309 8000 25 4.3 45.7 7.9 61.5 10.6 69.6 12
1310 9000 28.1 4.8 51.4 8.9 69.2 11.9 78.3 13.5
1410 10000 31.3 5.4 57.1 9.9 76.9 13.3 87 15
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1411 11000 34.3 5.9 62.9 10.8 84.6 14.6 95.7 16.5
1511 12000 37.5 6.5 68.6 11.8 92.3 15.9 104.3 18
1512 13000 40.6 7 74.3 12.8 100 17.2 113 19.5
1712 15000 46.9 8.1 85.7 14.8 115.4 19.9 130.4 22.5
2012 18000 56.3 9.7 102.9 17.7 138.5 23.9 156.5 27
2013 20000 62.5 10.8 114.3 19.7 153.8 26.5 173.9 30
2114 23000 71.9 12.4 131.4 22.7 176.9 30.5 200 34.5
2314 25000 78.1 13.5 142.9 24.6 192.3 33.2 217.4 37.5
2415 28000 87.5 15.1 160 27.6 215.4 37.1 243.5 42
2416 30000 93.8 16.2 171.4 29.6 230.8 39.8 260.9 45
2417 33000 103.1 17.8 188.6 32.5 253.8 43.8 287 49.5
2418 35000 109.4 18.9 200 34.5 269.2 46.4 304.3 52.5
2420 40000 125 21.6 228.6 39.4 307.7 53.1 347.8 60
2621 45000 140.6 24.2 257.1 44.3 346.2 59.7 391.3 67.5
2821 50000 156.3 26.9 285.7 49.3 384.6 66.3 434.8 75
2823 55000 171.9 29.6 314.3 54.2 423.1 72.9 478.3 82.5
2924 60000 187.5 32.3 342.9 59.1 461.5 79.6 521.7 90
3026 65000 203.1 35 371.4 64 500 86.2 565.2 97.5
3226 70000 218.8 37.7 400 69 538.5 92.8 608.7 104.9
3228 75000 234.4 40.4 428.6 73.9 576.9 99.5 652.2 112.4
3428 80000 250 43.1 457.1 78.8 615.4 106.1 695.7 119.9
3430 90000 281.3 48.5 514.3 88.7 692.3 119.4 782.6 134.9
3632 100000 312.5 53.9 571.4 98.5 769.2 132.6 869.6 149.9
Note:
1. Chilled water is supplied at 7 °C, returned at 12 °C.
2. Under return air condition, entering dry bulb temperature is 27 °C, and wet bulb temperature is
19.5 °C.
3. The above parameters are for reference only; please contact us for customized working conditions, coil
configurations and cooling capacities.
4. The test is under air velocity of 2.75 m /s.
5. Please contact us if user requests for a nominal air flow greater than 100,000 m3/h.
Cooling Capacity and Water Flow VS Primary Air Flow
Unit
Model
Nominal
Air Flow
(m3/h)
2 rows 4 rows 6 rows 8 rows
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
Cooling
Capacity
(kW)
Water
Flow
(m3/h)
606 1500 10 1.7 19 3.3 24.6 4.2 27.8 4.8
706 2000 13.3 2.3 25.3 4.4 32.8 5.7 37 6.4
906 3000 20 3.4 38 6.5 49.2 8.5 55.6 9.6
907 3500 23.3 4 44.3 7.6 57.4 9.9 64.8 11.2
1007 4000 26.7 4.6 50.6 8.7 65.6 11.3 74.1 12.8
1008 5000 33.3 5.7 63.3 10.9 82 14.1 92.6 16
1208 6000 40 6.9 75.9 13.1 98.4 17 111.1 19.2
1308 7000 46.7 8 88.6 15.3 114.8 19.8 129.6 22.3
1309 8000 53.3 9.2 101.3 17.5 131.1 22.6 148.1 25.5
1310 9000 60 10.3 113.9 19.6 147.5 25.4 166.7 28.7
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Technological Innovation from NTU, Singapore 15
1410 10000 66.7 11.5 126.6 21.8 163.9 28.3 185.2 31.9
1411 11000 73.3 12.6 139.2 24 180.3 31.1 203.7 35.1
1511 12000 80 13.8 151.9 26.2 196.7 33.9 222.2 38.3
1512 13000 86.7 14.9 164.6 28.4 213.1 36.7 240.7 41.5
1712 15000 100 17.2 189.9 32.7 245.9 42.4 277.8 47.9
2012 18000 120 20.7 227.8 39.3 295.1 50.9 333.3 57.7
2013 20000 133.3 23 253.2 43.6 327.9 56.5 370.4 63.9
2114 23000 153.3 26.4 291.1 50.2 377 65 425.9 73.4
2314 25000 166.7 28.7 316.5 54.6 409.8 70.7 463 79.8
2415 28000 186.7 32.2 354.4 61.1 459 79.1 518.5 89.4
2416 30000 200 34.5 379.7 65.5 491.8 84.8 554.6 95.8
2417 33000 220 37.9 417.7 72 541 93.3 611.1 105.4
2418 35000 233.3 40.2 443 76.4 573.8 98.9 648.1 111.7
2420 40000 266.7 46 506.3 87.3 655.7 113.1 740.7 127.7
2621 45000 300 51.7 569.6 98.2 737.7 127.2 833.3 143.7
2821 50000 333.3 57.5 632.9 109.1 819.7 141.3 925.9 159.6
2823 55000 366.7 63.2 696.2 120 901.6 155.5 1018.5 175.6
2924 60000 400 69 759.5 130.9 983.6 169.6 1111.1 191.6
3026 65000 433.3 74.4 822.8 141.9 1065.6 183.7 1203.7 207.5
3226 70000 466.7 80.5 886.1 152.8 1147.5 197.9 1296.3 223.5
3228 75000 500 86.2 949.4 163.7 1229.5 212 1388.9 239.5
3428 80000 533.5 92 1012.7 174.6 1311.5 226.1 1481.5 255.4
3430 90000 600 103.4 1139.2 240.1 1475.4 254.4 1666.7 287.4
3632 100000 666.7 114.9 1265.8 218.2 1639.3 282.6 1851.9 319.3
Note:
1. Chilled water is supplied at 7 °C, and returned water at 12°C.
2. Under return air condition, entering dry bulb temperature is 35°C, and wet bulb temperature is 28°C.
3. The above parameters are for reference only; please contact us for customized working condition,
coil configuration and cooling capacity.
4. The test is under air velocity of 2.75 m /s.
5. Please contact us if user requests for nominal air flow greater than 100,000 m3/h.
4.2 Heating Coil
Air T&D uses finned galvanized steel tubes as electrical heater coil material. We also provide stainless steel
tubes as alternative coil material. All electrical coils are placed into a galvanized sheet casing. High capacity
electrical heating coils can be split into the desired stages upon demand.
Heat Capacity and Water Flow VS Fresh/Return Air Flow
Unit
Model
Nominal
Air Flow
(m3/h)
Under return air condition (dry bulb
temperature is 15 °C)
Under fresh air condition (dry bulb
temperature is 7 °C)
Heat Capacity (kW) Heat Capacity (kW)
1 row 2 rows 3 rows 4 rows 1 row 2 rows 3 rows 4 rows
606 1500 4.7 9.6 12.7 14.9 5.7 11.1 15.2 18.3
706 2000 6.2 12.8 16.9 19.8 7.5 14.8 20.2 24.4
906 3000 9.3 19.2 25.4 29.7 11.3 22.2 30.3 36.6
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Technological Innovation from NTU, Singapore 16
907 3500 10.9 22.4 29.7 34.7 13.2 25.9 35.4 42.7
1007 4000 12.4 25.6 33.9 39.6 15.1 29.6 40.4 48.8
1008 5000 15.5 32.1 42.4 49.5 18.9 37 50.5 61
1208 6000 18.6 38.5 50.8 59.4 22.6 44.4 60.6 73.2
1308 7000 21.7 44.9 59.3 69.3 26.4 51.9 70.7 85.4
1309 8000 24.8 51.3 67.8 79.2 30.2 59.3 80.8 97.6
1310 9000 28 57.7 76.3 89.1 34 66.7 90.9 109.8
1410 10000 31.1 64.1 84.7 99 37.7 74.1 101 122
1411 11000 34.2 70.5 93.2 108.9 41.5 81.5 111.1 134.1
1511 12000 37.3 76.9 101.7 118.8 45.3 88.9 121.2 146.3
1512 13000 40.4 83.3 110.2 128.7 49.1 96.3 131.3 158.5
1712 15000 46.6 96.2 127.1 148.5 56.6 111.1 151.5 182.9
2012 18000 55.9 115.4 152.5 178.2 67.9 133.3 181.8 219.5
2013 20000 62.1 128.2 169.5 198 75.5 148.1 202 243.9
2114 23000 71.4 147.4 194.9 227.7 86.8 170.4 232.3 280.5
2314 25000 77.6 160.3 211.9 247.5 94.3 185.2 252.5 304.9
2415 28000 87 179.5 237.3 277.2 105.7 207.4 282.8 341.5
2416 30000 93.2 192.3 254.2 297 113.2 222.2 303 365.9
2417 33000 102.5 211.5 279.7 326.7 124.5 244.4 333.3 402.4
2418 35000 108.7 224.4 296.6 346.5 132.1 259.3 353.5 426.8
2420 40000 124.5 256.8 339.5 395.4 150.8 296.8 404.5 488.2
2621 45000 139.8 288.5 381.4 445.5 169.8 333.3 454.5 548.8
2821 50000 155.3 320.5 423.7 495 188.7 370.4 505.1 609.8
2823 55000 170.8 352.6 466.1 544.6 207.5 407.4 555.6 670.7
2924 60000 186.3 384.6 508.5 594.1 226.4 444.4 606.1 731.7
3026 65000 201.9 416.7 550.8 643.6 245.3 481.5 656.6 792.7
3226 70000 217.4 448.7 593.2 693.1 264.2 518.5 707.1 853.7
3228 75000 232.9 480.8 635.6 742.6 283 555.6 757.6 914.6
3428 80000 248.4 512.8 678 792.1 301.9 592.6 808.1 975.6
3430 90000 279.5 576.9 762.7 891.1 339.6 666.7 909.1 1097.6
3632 100000 310.6 641 847.5 990.1 377.4 740.7 1010.1 1219.5
Note:
1. Hot water is supplied at 60 °C, and returned at 50 °C.
2. Under return air condition, entering dry bulb temperature is 15 °C, and wet bulb temperature is 7 °C.
3. The above parameters are for reference only; please contact us for customized working condition, coil
configuration and cooling capacity.
4. The test is under air velocity of 2.75 m /s.
5. Please contact us if user requests for nominal air volume greater than 100,000 m3/h.
4.3 Filter
The basic function of filter cells is to prevent the accumulation of dust on the internal surfaces of coils
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Technological Innovation from NTU, Singapore 17
and panels, extending the efficient lifetime of the air handling unit. Dust accumulation is an unwanted
condition which reduces the heat transfer efficiency of coils. Additionally, use of high particle efficiency
filters is required for environments where the air must be kept free of air-borne harmful
microorganisms (pharmacological production facilities, operating rooms, clean rooms, microchip
production facilities). For this reason, various filter classes with the ability to filter particles of various
diameters have been developed.
Air T&D filter cells are distinguished for their design which reduces filter pass pressure drop by
minimizing the rate of filtration. To this end, cell dimensions are designed in proportion to filter
dimensions. The special spring clip casing design provides a high level of impermeability. This feature
is particularly important for air handling units since it could prevent microbiological proliferation. In
addition to these features, filter cells have been designed to facilitate easy maintenance thanks to their
wide filter covers and spring clip filter casings. Differential pressure stats for measuring filter
occupancy can also be used as an option. In Air T&D air handling units, various filtering options are
applied and optimum options are offered depending on the place of use and upon requirements. Filter
selection should be done by considering all these properties to extend filter life span and lower
maintenance costs.
Panel Filter:
Manufactured in G3 and G4 classes, these filters are produced from high quality galvanized steel, PVC
or fiberglass material. The decisive point in the design of these filters which have a gravimetric
efficiency of 85 - 95%, is creating a corrugated structure and hence a larger filtering surface. Panel
filters which can withstand temperatures of up to 180°C are used in Air T&D air handling units for pre-
filtration to lengthen the usage lifetime of higher particle efficiency filters. Panel filters are allowed to
be reused after washing, which lowers the operational and maintenance costs, and thus becomes the
most popular filter type of choice.
Bag Filter:
Manufactured in various classes from G4 to F9, bag filters are produced with galvanized frames as a
standard. The filtering element is produced from fiberglass. Its extended surface design leads to low
air flow rates, thus facilitating low pressure drops, high dust capturing capacity, long usage lifespan
and low energy costs. Bag filters are capable of providing solutions for all types of air handling units.
For example, rigid type bag filters with a plastic frame design are popular in the market since they can
be used in both downstream and upstream.
Pressure Drop for Different Filters under Air Velocity of 2.75 m /s
Filter type Initial Pressure Drop (Pa) Final Pressure Drop (Pa) Design Pressure Drop (Pa)
G3 plate filter 35 80 65
G4 plate filter 40 100 80
G3 bag filter 30 60 50
G4 bag filter 35 70 55
F5 bag filter 55 110 90
F6 bag filter 70 140 110
F7 bag filter 90 180 140
F8 bag filter 110 220 180
F9 bag filter 140 280 220
H10 150 300 240
H11 180 360 290
H12 190 380 300
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Technological Innovation from NTU, Singapore 18
H13 220 440 350
Filtration Performance for Different Filters
Filter Type Filter Material Filtration Class Filtration Efficiency Test Method
Primary Efficiency
Panel Filter
Synthetic Fiber G3 80 – 90 % Gravimetric Method
G4 > 90 %
Primary Efficiency
Bag Filter
Synthetic Fiber G3 80 – 90 % Gravimetric Method
G4 > 90 %
Medium Efficiency
Bag Filter
Synthetic Fiber
Or Glass Fiber
F5 40 – 60 % Colorimetric Method
F6 60 – 80 %
F7 80 – 90 %
F8 90 – 95 %
F9 >= 95 %
Sub-High
Efficiency
Filter
Glass Fiber H10 85 % Most Penetration
Particle Size (MPPS)
Filter Efficiency Configuration for Different Types of AHU
Types General
configuration Configuration for electronic factory
Purification class − Class 5 Class 6 Class 7 Class 8 Class 8.3
Primary efficiency G3 G4(F5) G4(F5) G4(F5) G4 G3
Medium efficiency F6 F8 F8 F8 F7 F6
Higher medium /sub-
high efficiency − H10 F9 − − −
Types Configuration for
tobacco factory Configuration for pharmaceutical industry
Purification class − Class 5 Class 7 Class 8 Class 8.3
Primary efficiency G4 G4(F5) G4(F5) G4 G3
Medium efficiency F7 F8 F8 F7 F6
Higher medium / sub-
high efficiency − H10 − − −
Efficiency Comparisons of Air T&D Filer in Europe, U.S.A and China Protocol
Unit model 0606 0706 0906 0907 1007 1008 1208 1308 1309 1310 1410 1411 1511 1512 1712
Filter
dimension
592 * 592
- - - - 2 2 1 2 - 2 2 - - 2 -
287 * 592
- - - 1 1 1 - - 2 2 2 - - - -
490 * 592
- 1 1 1 - - 1 - 2 - - 4 4 2 3
490 * 490
1 - - - - - - - - - - - - - 3
Unit model 2012 2013 2114 2314 2415 2416 2417 2418 2420 2621 2821 2823 2924 3026 3226
Filter
dimension
592 * 592
3 6 4 6 6 6 6 6 9 12 12 12 12 16 20
287 * 592
- - 2 2 - 3 3 - 3 - 3 7 7 4 -
490 * 592
3 - 2 - 2 2 2 5 - - - - - - -
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Technological Innovation from NTU, Singapore 19
490 * 490
- - - - - - - 1 - - - - - - -
Unit model 3228 3428 3430 3632 3634 4034 4234 4535 4835 5135 5435 5735 6036 6236
Filter
dimension
592 * 592
- - - - 2 2 1 2 - 2 2 - - 2
287 * 592
- - - 1 1 1 - - 2 2 2 - - -
490 * 592
- 1 1 1 - - 1 - 2 - - 4 4 2
490 * 490
1 - - - - - - - - - - - - -
Note:
The table above could only be used as reference for build-in panel filter, filter bag filter. The filter
dimensions provided in above tables are under Air T&D’s standard.
4.4 Fan/ EC Fan/ Fan Matrix
The air handling unit includes a fan cell for the purpose of facilitating air circulation through an aspirator
and/or ventilator, depending on the requirements of the environment. While forward curved fans are
preferred for AHUs within the low pressure range, backward curved fans can be used for AHUs within the
medium and high pressure ranges. In addition to these, fans are commonly preferred due to their efficiency
and low noise level operation. Depending on design conditions, plug (without scroll case, single inlet, direct
coupled) fans can also be used.
Fans used in Air T&D air handling units are manufactured from galvanized sheet metal. Forward and
backward curved fans are statically balanced according to the ISO 1940-G6.3 standard. Flexible connection
is used between the air exhaust and the unit body to dampen vibrations. Flexible connections which used
to connect the ductwork from outside are also available. Diffusers are installed to build interconnections
between the fan and other cells. The basic purpose of the diffuser is to distribute the air flow in the
subsequent cell evenly within the cell.
Performance Features for Different Fans
Fan types Forward curved Backward curved Radial
Characteristics Wide range for air flow, low noise
level, low rotation speed
Competitive efficiency, low noise
level, flat curve behavior, high
strength
Competitive efficiency, low
noise level, flat curve
behavior, high strength
Application
range
Low air pressure, or for occasions
with special requirements (e.g.
noise level)
Large air pressure, large air flow,
wide performance range
Large air pressure, large air
flow
Principle of
selection
Small air flow range, avoiding to
use fans with high rotation speed
Medium/low air pressure, large
air flow
Large air flow, medium to
high air pressure, especially
for purification air-
conditioning units
EC (Electronically Commutated) Motor Fans
Depending on global and nationwide research, the highest potential whereby electrical energy saving can
be achieved has to do with electrical motors. The leading factor in implementing this responsibility is EC
technology with the high energy economy it provides.
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 20
The EC motor is a DC motor with electronic commutation. This means that the motor speed can be
controlled very effectively. The motor speed is controlled by how rapidly the magnetic flux in the motor
switches. The permanent magnets of the rotor create the magnetic flux in the motor. Speed control is
carried out using a control unit integrated with the motor. Control signal is in 0–10 V, starting at 1.4 V and
stopping at <1 V. The EC motor is efficient throughout its operating range and is brushless, requiring less
maintenance.
The Air T&D AHU can be equipped with an EC motors by customer demand. Details distinguishing it from
other products on the market, and some advantages for the manufacturer and end user are as follows:
- Process controller, speed control device or driver, electrical filters and overload protection (for
motor and electronics) elements are all within the motor.
- Low noise and vibration levels are achieved throughout the entire operational range.
- 100% speed control is available without using additional components.
- Fixed performance throughout the full supply current range.
- Integrated DC supply source for sensors.
- Programmable analogue outlet.
- Integrated PID, access to and ability to modify PID parameters depending on the algorithm.
- Integrated alarm, access to a wide range of failure, error and actual details throughout the
operation period depending on the EEP- ROM memory.
Fan Selection
System requirements influencing fan selection are air quantity, static pressure, non-standard air density,
noise level or use of the fan’s operating environment, as well as properties of the useable area and cooling
load. Air T&D will select fan types and customize fan schemes on user demands.
- The first step in a selection process is to select fan type. If that the fan is to be installed into an
AHU, the most common question is whether to select a centrifugal fan in casing or without
casing. Centrifugal fan in casing usually has slightly higher efficiency than a fan without casing,
but in an AHU it is more vulnerable to the installation effect, which reduces its efficiency.
Therefore, for AHUs, a backward curved centrifugal fan without casing is the preferred option for
majority of AHUs.
- The next step is to select a fan motor. Because of the high efficiency, EC motors should be used
whenever possible. Asynchronous AC motors with variable frequency drives are the second
option. When selecting the fan size, several sizes are usually able to provide the required airflow
and pressure in the operating point. The size, where the operating point is closest to the best
efficiency point and motor electrical input is the lowest, should be selected.
Fan Matrix
It is a combination of smaller fans built into a wall section to replace a traditional single large fan. The
custom air handling units they supply using this technology incorporate multiple direct-drive centrifugal
plenum fans, assembled in a rectangular array of 4 to 9+ fans, all discharging into a single plenum. The fans
used are specially designed and optimized for use. Each fan array is usually controlled by a single variable
speed drive, which controls the speed of all fans simultaneously. The use of multiple direct-drive fans
operating in parallel improves reliability by providing redundancy. Optimized fan wheel construction and
improved internal aerodynamics further enhance energy performance.
In a traditional system using direct drive motors, it is common to see motor loads at 1/4th to 1/8th of their
nameplate rating for a significant portion of their operation hours, resulting in reduced power factors and
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 21
lower fan and motor efficiencies. To more closely match site conditions, the fan matrix wall can be tuned
by turning one or more fans off to allow remaining fans and motors to be fully loaded at or near peak
efficiency. Air flow rates can be varied through use of a variable speed drive, by turning fans on and off, or
by using both control strategies in combination. The advantages are listed at the following as the key
reasons to employ this fan arrangement:
- Shorten the unit
- Quiet operation
- Energy savings through optimized performance
- Redundancy
- Lower maintenance costs
- Good for retrofits
The following is a sample drawing of Air T&D fan matrix wall (with 2 X 3 fan matrix).
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 22
4.5 Humidifier
The humidification unit is used to control the relative humidity of the ambient air by increasing the
absolute humidity of air in the air handling unit. The choice of humidification equipment is depending
on user requirements for the indoor environment. Various types of humidifiers can be used in Air
T&D air handling units according to the application type.
Saturated Steam Humidifier
The most commonly used humidification method is to use dry steam to humidify the air. The user
must provide 0.1 – 0.4MPa saturated steam source. We made use of double insulation steam
pipe clamp stainless steel as material for dry steam humidification equipment, which has a
beautiful appearance, corrosion resistance and extra-long lifetime. We provide a unique muffler
measures to enables absolutely silent injection process. The double insulation design ensures that
there is no condensed water discharge phenomenon occurs inside the tube, and can also achieve
high-precision humidification control.
Wet Film Humidifier
Wet film humidifier is the most simple and economical humidify equipment; users only need to
provide water. Wet film humidifier characterized by increase humidifying space, could also
eliminate or replace the use of water flap. However, due to the presence of humidification
hysteresis in control process, wet film humidifier are not suitable to be used in occasions with high
requirements on cleanliness and humidity. It is commonly used in comfort air conditioning systems.
Immersed Electrode Steam Humidifier
Electrode humidifier makes use of conductivity of water to heat up and produce steam for air
humidification, and it is suitable for offices, manufacturing plant, computer rooms and sterile field.
Due to its own characteristics, it will not cause fire when working under low water capacity; it is a
safe and reliable humidification method. However, it does have certain requirements on water
quality; generally, it uses tap water, but cannot use purified water or distilled water. The electrode
humidifier can perform precise adjustment of humidification.
Spray Air Washer Humidifier
T he working principle of h igh-pressure spray / high-pressure fog humidifier is to increase pump
pressure, and spray high-pressure water through the nozzle. Due to the small size of spray particles
ejected out from high-pressure nozzle, it has high humidification efficiency, humidity control
precision can be controlled within ±8 ~±12%. It is suitable to use in manufacturing industries.
Selection of Humidification Type
Humidification Type Isothermal humidification Equal-enthalpy humidification
Humidifier types Saturated steam
humidifier Electrode humidifier High-pressure spray humidifier Wet film humidifier
Humidification
principle
Introduce steam
directly
Current pass through
water and heat up the
water to produce steam
Spray high-pressure water
through nozzles, exchanging
heat with air and then
evaporating
Water evaporate
when air pass
through the wet film
Humidification
capacity Determined by humidifier itself
Determined air condition before humidification and
humidifier itself
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Technological Innovation from NTU, Singapore 23
Application range Suitable for high-precision control occasions Suitable for general precision control occasions
4.6 Dehumidifier
Quality HVAC systems that deliver consistent cooling and precision control are essential to the overall
operations and health of most commercial facilities. Nowadays, engineers and property owners are taking
dehumidification as a key consideration in the design of HVAC systems. The benefits are clear: the removal
of moisture in air could improve indoor air quality (IAQ), (or most of time we say IEQ, indoor environment
quality) as well as provide better indoor comfort level, in the meanwhile supporting facility operations and
maximizing the life of building, furnishings and equipment.
Air T&D dehumidification options help significantly reduce moisture-related damage and degradation to
the facility and other assets, preventing peeling paint, odor problems and loss of structural integrity. From
the moderate dehumidification requirements of typical office environments, to moisture-sensitive
museums, printing plants and surgical suites, the comprehensive approach of Air T&D offers solutions that
are right for users’ facility and budget.
Traditional Dehumidification solution
Name Cooling Dehumidification (Cooling Method) Rotor Dehumidification (Chemical Method)
Feature Cooling the air below the dew point, then
removing the condensed moisture Dehumidifying by the adsorption of solid drier
Scope of
Application
Applying for the temperature range higher
than the dew point Applying for low dew point
Rules of Selection Dehumidifier can remove all the indoor
moisture load
Reasonably distribute air flow, maximize the
dehumidifier capacity to achieve the best
dehumidifying effect
Note: Please contact our company if the customers have requirements of dehumidification; we will
design the units according to customers' specific parameters.
Air T&D Innovative Dehumidification Solution
Air T&D provides the most energy efficient Liquid Desiccant Dehumidification System (LDDS) and Liquid
Desiccant Air-Conditioning (LDAC) on the world market. Through the breakthrough on the design and
operation of LDDS & LDAC technologies, our products can achieve 30% to 50% energy savings when applied
to residential and commercial building HVAC systems.
LDDS: a series of standard products with single unit air treatment capacities ranging from 500
m3/h to 4,000m3/h. Since the products are modular designed, we can meet all users need
through module combination. Our professional design team can also tailor the design for any
special requirements from customers.
LDAC: The LDAC are designed for general building HVAC applications to realize independent
control of air temperature and humidity, with air flow ranging from 1000 m3/h to 40,000m3/h.
LDAC can integrate with existing HAVC components easily to supply cool, dry and clean air into
occupied space.
Both LDDS &LDAC have been effectively integrated with the following energy sources:
>>> Modular Air Handing Units
Technological Innovation from NTU, Singapore 24
• Utilize two-way heat pump to supply cooling and heating energy for dehumidifier and
regenerator simultaneously. This integration enables the system to operate independently and is
suitable for the application that renewable and cooling energy are not conveniently available
• Integrate the LDDS with existing HVAC systems to employ chilled water and condensation heat as
external energy to drive the de-humidifier and regenerator, respectively.
• Combine the renewable energy and grid power to drive LDDS operation. Our intelligent control
technology enables the system to operate in hybrid mode and seek a maximum usage of
renewable energy while taking the grid power as an auxiliary.
Key Innovations
Hybrid Operation: In conventional systems, desiccant solutions continuously exchange between
dehumidification and regeneration columns in order to maintain the pre-specified concentrations. Our
patented hybrid operation technology makes the desiccant solutions cycling inside the each tower for a
specified concentration range, and exchanges the solutions once the limit is reached to avoid the energy
waste and improve the system efficiency.
Energy Recovery: Conventional systems require a large amount of heat energy for solution regeneration.
Most of the heat energy is wasted as the regenerated air is discharged directly. Our LDDS &LDAC are able
to recover most of the heat with a hot water pipe energy recovery device. This structure innovation results
in 60% regeneration energy saving com-pared with the current technologies.
Vacuum Regeneration: High desiccant solution regeneration temperature has been become a key barrier
for wide application of LDDS & LDAC. Our novel designed absorption-based liquid desiccant regenerator
can drastically reduce the regeneration temperature from 80°C (conventional type) to 40°C, thus most low
grade energy, such as solar energy, wasted heat from chiller, can be reused effectively to concentrate the
desiccant solution. Moreover, no fan is equipped so that the system is more energy-efficient and reliable.
Intelligent Control: The ability of liquid desiccant to remove water vapor from air is determined by the
temperature, flowrate and concentration of the solution. Air humidity ratio of dehumidifiers can be
controlled by regulating the three variables. We have developed an integrated controller with intelligent
algorithm. Through the advanced control technologies, the humidity ratio of supply air can be accurately
controlled from 3g water/kg dry air to 10g water/kg dry air.
Distributed Operation: In commercial and residential building applications, dehumidifiers are usually inside
the AHU rooms located in different floors. The heating sources, either waste heat from chiller or solar
energy, are available in plant room or on the roof top. The hybrid operation provides a possibility for
dehumidifier and regenerator running in different places which offers an opportunity for LDDS &LDAC being
efficiently applied in building ACMV systems.
Zero crossovers: Air T&D’s innovative design on solution distribution nozzle and vane type mist eliminator
can achieve both zero solution crossovers and minimal pressure drop.
4.7 Energy Recovery Unit
Energy Recovery units (ERUs) used in Air T&D air conditioning systems preheat or precool the fresh air taken
in outdoor conditions using exhaust air, bringing the enthalpy and temperature of fresh air to interior space
conditions. However, in these systems, if energy is taken from another system, Energy Recovery does not
occur. According to VDI 2071, the transfer of mass is not Energy Recovery. Thus, Energy Recovery cannot
be achieved by mixing air.
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Technological Innovation from NTU, Singapore 25
Sensible heat transfer is made primarily in ERUs. Latent heat can be transferred depending on the structure
of the HRUs. Air T&D provides three types of ERU for different application places, as shown in the following
table.
Selection of Energy Recovery Unit
Name Wheel Energy Recovery
equipment
Plate Energy Recovery
equipment Energy Recovery loop
Properties
High Energy Recovery efficiency,
cross contamination, high capital
cost. Sensible and latent heat (total
heat) recovery
Preventing air contaminations,
reliable operation, Sensible
and latent heat (total heat)
recovery
Completely isolated air
flow, sensible Energy
Recovery only
Range of
application
Products used in civil and industrial
buildings
Suitable for small air flow,
small recovery capacity
occasions such as hospital and
laboratories
Special occasions such as
animal laboratories
Note: Please contact us before ordering, we would provide dedicated design to meet user requirements.
Performance for wheel Energy Recovery
Air velocity m/s 1.5 2 2.5 3 3.5 4 4.5 5
H /W D Weight
Recovery
efficiency % 80 78 76 74 72 70 68 66
Air
pressure
drop
Pa 79 89 110 138 160 190 220 250
Models Air treatment capacity mm mm kg
500 m3/h 420 560 700 840 980 1120 1260 1400 750 320 94
600 m3/h 630 840 1050 1260 1470 1680 1890 2100 850 320 107
700 m3/h 890 1190 1480 1780 2080 2370 2670 2970 950 320 117
800 m3/h 1190 1590 1980 2380 2780 3170 3570 3970 1050 320 132
900 m3/h 1540 2050 2570 3080 3590 4110 4620 5130 1150 320 145
1000 m3/h 1920 2560 3200 3840 4480 5120 5760 6400 1200 320 161
1100 m3/h 2350 3130 3920 4700 5480 6270 7050 8300 1250 320 177
1200 m3/h 2810 3750 4680 5620 6560 7490 8430 9370 1350 320 204
1300 m3/h 3320 4430 5530 6640 7750 8850 9960 11070 1450 320 229
1400 m3/h 3870 5160 6450 7740 9030 10320 11610 12900 1550 320 252
1500 m3/h 4470 5960 7450 8940 10430 11920 13410 14900 1650 320 266
1600 m3/h 5060 6750 8430 10120 11810 13490 15180 16870 1750 320 301
1700 m3/h 5730 7640 8550 11460 13370 15280 17190 19100 1850 320 322
1800 m3/h 6450 8600 10750 12900 15050 17200 19350 21500 1950 320 346
1900 m3/h 7200 9600 12000 14400 16800 19200 21600 24000 2050 320 369
2000 m3/h 8000 10670 13330 16000 18670 21330 24000 26670 2150 320 392
2200 m3/h 9530 12710 15880 19060 22240 25410 28590 31770 2400 320 549
2400 m3/h 11410 15210 19020 22820 26620 30430 34230 38030 2600 320 693
2600 m3/h 13460 17950 22430 26920 31410 35890 40380 44870 2800 430 838
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Technological Innovation from NTU, Singapore 26
2800 m3/h 15680 20910 26130 31360 36590 41810 47040 52270 3000 430 913
3000 m3/h 18060 24080 30100 36120 42140 48160 54180 60200 3200 430 991
3200 m3/h 20610 27480 34350 41220 48090 54960 61830 68700 3400 430 1075
3400 m3/h 23330 31110 38880 46660 54440 62210 69990 77770 3600 430 1158
3600 m3/h 26220 34960 43700 52440 61180 69920 78660 87400 3800 430 1243
3800 m3/h 29270 39030 48780 58540 68300 78050 87810 97570 4000 430 1331
4000 m3/h 32490 43320 54150 64980 75810 86640 97470 108300 4200 430 1422
4200 m3/h 35880 47840 59800 71760 83720 95680 107640 119600 4400 430 1901
4400 m3/h 39440 52590 65730 78880 92030 105170 118320 131470 4600 430 2014
4600 m3/h 43160 57550 71930 86320 100710 115090 129480 143870 4800 430 2130
4800 m3/h 47050 62730 78420 94100 109780 125470 141150 156830 5000 430 2248
5000 m3/h 51110 68150 85180 102220 119260 136290 153330 170370 5200 430 2350
4.8 Air Disinfector
Building design and construction have been impacted by ever evolving ASHRAE standards, and owners are
becoming more and more focused on not only heating/cooling/moving so much air, but also making sure
the HVAC design provided is energy efficient. Along with energy efficiency, many owners are also looking
for HVAC designs which will maintain and/or enhance indoor air quality. Today people spend more time
indoors than ever before. It has been proven that the air we breathe can make us feel unhealthy, deficient
and tired. This in fact does affect our well-being along with productivity. People expect the air they breathe
to be reasonably safe and comfortable. Yet indoor air can be laden with mold, mildew, dander, bacteria,
and viruses. As a result of those paradigm shifts, many owners and engineering firms are turning to
disinfection to meet the new and emerging requirements.
Disinfection by UV and Ozone
Name Disinfection by UV Ozone Generator
Feature - The dose of Ultraviolet Germicidal Lamp for
Air-conditioning System needs to be in the
range of 6000-7000 µ W s/𝑐𝑚2 (the product
of the average intensity of illumination and
the time of wind through the UV field)
- the sterilization rate of the general bacteria
and viruses can reach more than 90%
- can prevent the cross-infection effectively
- Disinfection: Ozone is a kind of board-spectrum,
high-efficiency and fast sanitizer. It can kill all kinds
of bacteria, virus and microorganism which can
make people and animals sick.
- Detoxification: Ozone can efficiently remove the
toxic gases such as CO, NO, SO2 and mustard gas by
oxidation reaction. Ozone owns the functions of
deodorant and deodorization.
Scope of
Application
Disinfection on the functional segments of Air
Handling Units in static and dynamic states:
filter, cooling coil, condensate drain pan and
etc.
Dynamic disinfection of air flow.
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Rules of
Selection
The selection for the power and position of UV
disinfection is according to the average
intensity of illumination and the exposure time.
The model selection is according to the room volume
and cleanliness class.
Clean class 0.1K 1K 10K 100K
Concentration
(mg/𝑚3) 40 38 30 20
4.9 Electronic Dust Precipitator
High-voltage electrostatic air-purifying sterilizer uses high voltage to ionize the air, let the particulate
matter and the microorganism in the air be charged through the polarized area, then collect the
charged particles through the duct-controlling area which is charged by opposite charges to break
the cell wall in a moment and kill the bacterial and virus. The creative points of such technology
are:
• The resistance in the duct-controlling area is small, a n d duct-removing area can achieve
the maximum of board electrostatic dust removing through unit ventilation cross-section.
• The polarized area, the duct-controlling area and back- pressure area form three-area
high-voltage electric fields, which have the functions such as killing bacterial, removing dust
and odor with high efficiency.
Performance Parameters of High-Voltage Electrostatic Air-Purifying Sterilizer
Items Performance
Index
Items Performance Index
Dust removing
efficiency and
purifying effect by
one-time pass
PM1.0 >=98.9% Bactericidal efficiency after 30
minutes from start up
>=99.92%
PM2.0 >=99.5% Purifying efficiency of Methanol
(concentration after 1 hour after
start-up)
0.03mg/m3
PM5.0 >=99.4% Purifying efficiency of TVOC 85%
PM10 0.015mg/m3 The concentration of Ozone
generated during the operation
0.005mg/m3
Bactericidal efficiency by one-
time pass
>=94.69% Continuous operating results Efficiency
decreasing <=0.1%
Equipment Resistance 30Pa
4.10 Activated Carbon Filter
Principle
Activated Carbon Chemical Filter can clean the chemical pollutants in the air, such as odorant,
ammonia, SO2, VOCs and etc., satisfying the requirements of industry condition, environment
protection and civil use. We need to know the followings before we select the model of
Activated Carbon: type of the pollutants, concentration of the pollutants, a i r temperature and
relative humidity.
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Carbon filters can be used efficiently up to 40°C temperature and 70% relative humidity. In case high
efficiency pre-filtration (F7-F9) is used in applications, filters are not filled with dust particles which
allows them to continue their true function of capturing gas molecules more efficiently and for a longer
period of time.
Absorptivity of regular carbon decreases with increasing humidity, yet this is not an issue for active
carbon. Furthermore, in cases where the contact time is increased by lowering flow rate, active carbon
filters operate more efficiently. Another point which should be taken into consideration in carbon filter
selection is that they are 10-20% more adsorptive when loaded to 50% of their total capacity.
Properties
Manufactured as cylindrical cartridges, active carbon filter is used in the filtration of harmful and
malodorous gases. These filters are preferred in Air T&D air conditioning systems in cases where the
return air as well as fresh air needs to be purified for these harmful and malodorous gases.
Our company uses the Activated Carbon Casing which can be reused, having two types of the
frame: plastic and metal. Customers can entrust the professional factories to replace the Activated
Carbon (experienced users can replace the Activated Carbon by themselves), and they can reuse the
Activated Carbon after its regeneration as well. This will decrease the shipping fare of customers.
Activated Carbon Chemical Filters should be allocated before or behind the conventional filters.
The former is for protection, preventing the duct from obstructing the microporous structure of the
Activated Carbon. The latter is for pre-protection, preventing the powder of the Activated Carbon from
polluting the ventilation system.
Harmful Gases in Typical Places
Typical Harmful Gases Places Typical Harmful Gases Places
Methanol Interior Decoration,
Hospital
Odorant, VOCs Interior Decoration, Airports,
Offices
Acid Gases Paper-making, Micro-
electronics
Stink livestock farm, Slaughter House,
Sewage Treatment Plant
Alkaline Gases livestock farm, Micro-
electronics
Mercury Vapor Electroplating, Electrification
Sulphur Oxides, Nitrogen
Oxides
Micro-electronics Radioactive Gases Underground Projects, Caves,
Nuclear Power Plant
4.11 Silencer
Silencers are elements which bring noise levels to desired levels while attenuating noise within air handling
units or ventilation ducts. Sound attenuation is achieved through the porous material found within the
silencer. In Air T&D applications where low noise levels are called for, silencing units are placed in front of
and/or behind fan cells. The sound attenuation is achieved by the sound absorbent material which has been
manufactured from foam glass with a fire rating of A2. The foam glass is selected in the range of 20-50
kg/m3.
Properties
Frontal surfaces of silencers should be covered with sheet metal to prevent the air from passing directly
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over the foam glass material. If the air would be passed directly over the foam glass material, very high
pressure losses will occur in the porous environment, hence on the foam glass. While silencers serve basic
their function of attenuating sound, they cause pressure losses resulting from air flow within the air
handling unit or the ventilation duct. For this reason, silencers that are placed at specific distances should
be designed to make sure their frontal surfaces that are perpendicular to air flow will lead to minimal
pressure drops, hence eliminating needless pressure losses. For this reason, frontal surfaces of silencers
have plain, triangular and curved forms. Pressure losses occurring within the silencer cell has been
examined for a simulated silencer cell selected for the experimental setup.
Silencer Selection
Name Resistive Silencer Micro-perforated Silencer
Structure - Applying the galvanized steel to
form the frame.
- Using the sound absorbent material
inside and the screen board on the
surface.
Applying the galvanized steel and other steel materials.
Feature - Being able to absorb noise of
different frequencies by changing the
thickness of resistive silencer.
– The sound attenuation dose is large
and the head loss is small.
- Being able to broaden the range of silence frequency
and control the silencer with different central
frequency by changing the perforation diameters and
rate.
- The head loss is small and regenerated noise is low.
Scope of Application - The maximum air flow velocity is 10
m/s.
-Suitable for normal air-conditioning
systems.
- The maximum air flow velocity is 20 m/s.
- Suitable for clean air-conditioning systems or easily
dust-collecting cases.
Studies have shown that intake and discharge frontal surfaces of silencers should have a curved form. It has
been observed that this provides a 26% reduction in pressure losses occurring within the silencer cell.
Experimental studies have also shown that maximum sound attenuation is achieved with the silencer with
curved intake and discharge surfaces. For this reason, silencers with curved intake and discharge surfaces
are preferred in Air T&D air handling units.
Performance parameters of resistive silencer
Length of
Silencer (Modulus)
Values of noise attenuation under different Octave Band (dB)
63Hz 125Hz 250Hz 500Hz 1kHz 2kHz 4kHz 8kHz
6M 2 5 12 13 15 13 11 9
8M 3 8 18 19 22 18 13 11
12M 4 11 23 23 28 23 15 12
Performance parameters of micro-perforated silencer
Length of Silencer
(Modulus)
Values of noise attenuation under different Octave Band (dB)
63Hz 125Hz 250Hz 500Hz 1kHz 2kHz 4kHz 8kHz
6M 2 6 8 10 6 10 8 6
8M 3 8 9 12 7 12 10 8
12M 4 10 13 20 10 20 13 10
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5. Electrical and Automation System
5.1 Electrical System
According to customers' different requirements, Air T&D air handling units can select multiple electrical
controlling schemes, such as traditional direct starting, star-triangle starting and variable-frequency
starting/control. The main electrical components and elements of the control cabinet are all the
international mainstream products, in order to ensure the accurate controlling and electrical safety.
The Air T&D AHU is a ready-to-install functional part with an internal cabinet for all control and safety
apparatus. Only the electrical power supply and the control signals required from superordinate control
systems need to be connected to the installation site. It is factory tested and the test report is included in
the delivery.
Air T&D can extend the controlling functions such as local/remote switch control, BA control, interlocking
between fan and fire damper, interlocking between fan and other equipment, etc.
Schematic Diagram of Direct Starting (Motor Power ≤ 11KW)
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Schematic Diagram of Star-Delta Starting (Motor Power ≥ 15KW)
L1L2L3
QS
U V W
FU1
KM
KH
M3 ~
KMY
KM△
FU2
SB1
SB2
KM△
KM
KMY
KMYKT
KT KMY KM KM△
KH
Thermal relay
Circuit Breaker
Fuse
Delay Contact
AC Contactor
Stop Button
Start Button
Fan Motor
Description of Element
KH
QS
FU1-2
KT
KM
SB1
SB2
M1
Function Features:
- Fan starting and stopping controlling
- Output Power: Direct Starting for 0.25-11KW, star-triangle Starting for 15-55KW
- Indication for power, operation, and fault status
- Fire alarm interlocking device
- Circuit protection for overload, short circuit, anti-phase, loss of phase, overvoltage and under-
voltage, voltage imbalance
Variable-Frequency Starting/Control
A VFD provides adjustable speed control for single fan motor. Normally, an Air T&D AHU which has been
installed by VFD can vary the frequency within 30 to 50Hz in order to control motor rotation speed. It also
provides protection for the motor operation.
U V W
M23 ~
M13 ~
Disp
lay
VFD
1U
Fire contact
Heat Elimination Fan
Fan
L1 L2 L3L N PE
U1
1V
11
W1
1
U1
2V
12
W1
2
U1
1
V1
1
W1
1
U1
0
V1
0
W1
0
R S T U V W G
X1
COM
TA
TC
K1
FU1 U11
KM11
N
9
10
11
12
XT11
N
QF11
Terminal
Miniature Circuit Breaker
Fan Motor
Transducer
Cooling Machine
Auxiliary Contractor with Time
Fuse
Description of Electrical Element
XT11
QF11
M1
1U
K1
KM11
FU1
Notes for Variable-Frequency Starting/Control:
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- If using variable frequency motor, implement the controlling with the dotted-line part above,
and the power is 3/N/PE AC 380/220V 50HZ;
- If using the normal motor, no need the controlling of the dotted-line part, and the power is
3/N/PE AC 380/220V 50HZ;
- All alarms are inter-locking with Fire control.
Electrical Cabinet
• Installation Position: can be installed on the wall beside the units;
• Suggesting that the distance between the installation position and fan is less than 3m,
height (based on the operation plane) is greater than 1.4-1.5m.
• If the wire connecting distance is greater than 3m, the wire connection needs to be done by
customers themselves.
• The routing on site and the materials of duct should be done by customers themselves.
5.2 Automation System
All Air T&D handling units come equipped with Air T&D BSTAR software and controller mounted in a control
cabinet inside the unit. The controller is accessed by opening the external control cabinet door with an
emergency stop button. In order for the unit to run using the BSTAR controller and default controls program,
the VFD selector switch must be in “remote” mode.
The unit control program can be accessed using a computer with the Air T&D DAQ tool software and the
unit-mounted standalone display. The standalone display is mounted in a sealed cabinet on the front of the
unit next to the external disconnect. The operator display touch screen is an intuitive operator interface for
monitoring and changing building control functions. With the operator display you can:
• Choose specific chilled water flow within specified range.
• Choose specific air flow within specified range.
• Monitor space temperature, air flow, filter status, etc.
• Identify and troubleshoot problems.
• View and reset controller alarms.
Field elements
Type Elements Function and properties
Actuator
Motorized Flow
Control Valves
- Two-way: It is used to adjust the flow rate of the water entering the system
proportionally or On/Off controlled.
- Three-way: Allows the water coming from the system and the boiler to mix and
determines the ratio of mixture.
Damper Motors
- Normal: Air flow is used to control the control dampers in heating-cooling and
ventilation systems.
- Spring return: Air flow that has a safety function in heating-cooling and ventilation
systems is used to control the control dampers (e.g. freeze protection, smoke control,
hygiene).
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Sensor
Heat Sensors
- Duct type: It is used to measure the temperature in ventilation ducts.
- Room type: It is used to measure the indoor temperature in Heating-Cooling-
Ventilation systems.
- Outdoor type: It is used to measure the outside temperature.
- Freeze-free thermostat: It is used to protect the heating coils in the heating-cooling-
ventilation systems against the risk of freezing.
Humidity Sensors
- Duct type humidity sensor: It is used to measure the indo- or humidity and
temperature in Heating-Cooling-Ventilation systems.
- Room type humidity sensor: It is used to measure the indoor humidity and
temperature in Heating-Cooling Ventilation systems.
Pressure Sensor
- Differential pressure switch: It is used to sense the dirtiness of the air filters and
determine whether the fans are operating properly or receiving "belt breakage”
warning.
- Differential pressure sensor: It is mainly used to adjust flow rates of the fans and
monitor the filter dirtiness in a sensitive way.
Controllers
Two types of controller were designed by Air T&D to control central air-conditioning and air handling system,
i.e., Universal Controller and Terminal Controller. Optoelectronic isolation technology is adapted here to
the controller for accurate data acquisition and stable operation. The controllers provided the various data
collection ports to satisfy all the central air-conditioning systems. The advantages of the controller are as
follow:
- Using ARM chips, with more powerful real-time processing capabilities
- A more powerful processor, and more analog/digital I/O port
- Complex logic arithmetic function
- A friendly human-computer interface
- Simple, easy networking with RS-485
- Low-power design, no heat sink
U13 (Universal controller) L13A (Terminal controller)
BSTAR Software
BSTAR, provided by Air T&D, is a unique project development platform and management system for building
automation, which integrates abundant functions such as monitoring, control, optimization, fault detection
and diagnosis (FDD), and energy management (EMS) for HVAC systems. Inheriting the following advantages,
this platform and its tools bring effective BMS design and facility operation, and will make the buildings
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more energy-efficient and eco-friendly.
Excellent user interface, configurable assembles and competitive integrations. These increase
staff productivity, improve plant reliability and life, and save time/money during maintenance.
Dedicated and High-valued function modules. Auto-tuning control, FDD, and energy efficiency
analysis and optimization fill the gap between industry and academy.
Flexible and Extensive. Modular and structured framework facilitates function extensions, and
makes it easy to integrate with/into other BMS by the self-defined or third-party plugins.
Using this powerful tool software, customers can design basic controls and some advanced functions for
Air T&D air handling units:
• Temperature control
• Frequency converter operation for constant air flow or duct pressure
• On-demand control
• Heating and cooling shunts
• CO2-compension of fans
• Control of different types of heat exchanger
• Energy measurement
• Control of extra fans
• Control of temperature zones
• Communication via BACnet, or Modbus
• Monitoring via a C/S or B/S interface
The following is a sample HMI drawing for an air handling unit designed with BSTAR.
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6. Installation and Maintenance
6.1 Installation of Air Handling Unit
Rigging and Installation Procedure
1) The chassis of AHU is allocated by forks and lifting holes. There should be a protection pad
between the lifting rope and the unit preventing from the abrasion of the unit panel when
conveying the units, which may affect the performance and installation accuracy of AHU.
Lifting ropes should be kept away all water pipes and air duct interfaces outside the unit
during the AHU lifting process.
2) The unit should be installed on smooth concrete base (or channel steel base) which should
be 200-250mm higher than machinery hall floor. The length and width of the concrete
floor should be 200mm longer than the exterior frame of the unit, and there should be
floor drains around. The length and width of the steel channel beam should be the same as
the exterior frame of the unit, and there should have drains. The steel channel beam
should be prepared by customers themselves.
3) There should be sufficient space (not less than 1m) around the AHU for the installation,
operation, daily inspection and maintenance, especially for the piping, wiring and service
besides AHU doors.
4) When assembling AHU on the site, all the functional sections should be sealed by sealing
strips and clamped by the clamping equipment from the inside of unit and bottom dock,
preventing from air leakage. The joints can be coated with sealant if necessary.
5) After assembling all the parts as a whole, the inside sundries should be cleaned out.
Connecting the external pipe to the inlet and outlet pipes of the unit after the external
pipe being cleaned out, preventing coil pipes from blocking.
6) Installing the valves and joints on the outside of the AHU for the inlet and outlet pipes.
However, the weights of the valves, pipes and equipment which are connecting to the
outside of the unit cannot be bear by the AHU itself.
7) The motor should be connected to the power supply with the protection devices, and the
unit casing should be grounded. Reduced Voltage Starting Mode should be taken into
consideration for the motor which is greater than 15kW.
8) Condensation water pipe of the cooling coil should be installed with water blocks in order
to ensure the fluent water drainage. The water blocks should be prepared by customers
themselves.
Recommendation for installation
• Air handling unit is mounted over a leveled building site (foundation or construction). The
site should be sized for the specific camera.
• The weights of the air duct and water pipes which are connecting to the unit cannot be bear
by AHU itself.
• Sections are mounted one to another with sealing rubber between them. Connection
between them is made with bolt connection.
• When connect the air handling unit to duct system, flexible connections should be used
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to prevent transmissions of noise and vibration.
• The supplying pipes for heating and cooling units should not prevent the unit
maintenance. It is advisable to connect them through flexible pipe-connections.
• The indicated directions of inlet and outlet of water sections and counter -flow between
water and air must be observed.
• When connecting the coils to the heat exchanger, please be careful to prevent from
damaging the copper pipes.
• As for the coils which share the same pipes, they need to be heat-insulated and dew-
insulated, and they should be allocated with drain pipes as well.
• To prevention of freezing of water coil unit is recommended at the inlet section (fresh air)
to mount multiple leaf damper equipped with spring return actuator. Cooling coil and
Heating coil should be protected for anti-freezing in winter.
• Must be ensured siphon, placed before condensation line is connected to the building
installation.
• For heat exchanging coils which use the cooling and hot water as medium, the bottom side is
the water inlet and the top side the water outlet. The result should be opposite if using the
vapor as the medium. Furthermore, if using the vapor as the medium, there should be a
valve for draining of condensate water in the outside pipes, and releasing vapor should
be after the accomplishment of condensate water draining.
• The design pressure for the coils is 1.6MPa.
• To make a repair or maintenance of the unit, enough space in front of it must be ensured.
• The size of doors and entry of the technical room should be considered with the overall
dimensions of the installed sections when mounted, repaired or maintained.
Unit Model B1 (mm) B1 (mm) B2 (mm) B3 (mm)
Minimum free area to access to
the technical room
B4 (mm) H2 (mm) H3 (mm)
AHU 06XX 1350 800 1100 1650 900 1900 1400
AHU 09XX 1600 800 1100 1900 900 1900 1650
AHU 12XX 1850 900 1150 2150 900 1900 1900
AHU 16XX 2100 900 1250 2400 1000 1900 2150
AHU 20XX 2360 900 1350 2700 1100 1900 2400
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AHU 24XX 2360 900 1500 2700 1200 1950 2650
AHU 30XX 2360 900 1650 2700 1300 1950 -
AHU 36XX 2360 900 1850 2700 1500 1950 -
AHU 45XX 2360 900 2200 2700 1800 2250 -
Note:
- B1 – maintenance and cleaning of air filters
- B2 – repair and replacement of fan
- B3 – repair and replacement of heat exchangers
- B4 – minimum width of the door of technical room
- H2 – height when fan or coil is repaired
- H3 – minimum height when heat exchanger is repaired
- Air T&D reserves the right to modify the provided data, subject to product development and
advanced experiments.
6.2 Usage and Maintenance
Guideline
1) Power supply for unit motor is 380V/ 50Hz three-phase voltage supply. Please check the fan
before start up, make sure the fan operates normally, and the fan impellers should not strike
with the fan casing. All electrical and mechanical equipment must be checked by professional
technicians before operation. The rotation direction of fan impeller must be correct; the unit
could be powered up after inspection without abnormalities found.
2) When the unit has multi-functions, user should consider the interlocking interaction
requirements among functional sections. For example, electric heater section should be turned
on after the fan is operating, while the electric heater should be turned off before the fan is turn
off.
3) System adjustment should be done before fan operation. For example, when the unit has no
load, the air supply must be cut off at 3/4 position to ensure the motor is operated under the
rated current so as to avoid motor overheating. Air inlet damper and Air Supply damper should
not be tightened under operation to avoid AHU deformation under high pressure. Set interlock
between damper and motor switcher if necessary.
4) Water filter should be installed on coil pipes to avoid pipe jam; the filter should be cleaned
periodically. The chilled water and spray water should be pretreated to clean and soften.
5) The conditions of filter dust deposition should be checked regularly; the filter is needed to be
cleaned or replaced when the resistance reaches the set point. Take out the filter and pad it, and
use compressed air to reversely blow the filter. Wash the filter with detergent, air-dry it before
reuse. Cleaning and replacement process should be done with caution to avoid damages;
inspection on tightness between filter and its frame must be done. Filters made by non-woven
fabrics should be replaced and avoid reuse.
6) Check belt elasticity and tear/wear conditions regularly. User could adjust the screw under the
motor to reset the slipping belt to correct position. Belt should be replaced under severe tear
and wear. Motor bearing and fan bearing should be inspected and refuel regularly to improve
operation efficiency and extend service lifetime.
7) Entire cleanness for air handling unit should be done after 1-2 years operation. The inner surface
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of coper pipe should be cleaned by chemical solutions to remove incrustation scale. Meanwhile,
user should use water or compressed air to clean heat exchange fins.
8) When AHU does not work during winter time, water should be discharged from the coil; when
the unit is running during winter time, please ensure continuous water flow within the coil, and
close primary air supply damper to avoid frost damage of the coil.
9) Modular AHU must be controlled under professional technicians. There should have strict
systems of responsibility and operation instruction. The management should be provided for
daily equipment operation and maintenance.
Note
Please refer to the user manual for more details for installation, use and maintenance.
The AHU models, parameters and specifications of Air T&D might be changed without prior notifications
since the products will be continuously modified and improved. Thank you for your understanding!
Air T&D Pte Ltd
Address: 86 Phoenix Garden, Phoenix Heights, Singapore 668336
Phone: 0065-67906538
Fax: 0065-67933318
E-mail: [email protected]
www.airtd.com.sg