01 — Define the Duty
What must the equipment actually do?
- Move 15,000 m³/h of air
- Maintain 650 Pa static pressure
- Achieve a required filtration stage
- Transfer 800 kW between two water circuits
- Stabilize pressure in a closed hydronic loop
Home / Resources / Selection Center
Duty First. Model Second.
Select HVAC Components by Real Operating Conditions
A model number should be the result of selection—not the starting point. YONGFAN Selection Center helps engineers, contractors and system integrators organize the operating data needed to select HVAC components more accurately.
Start with the product family, then confirm the parameters that actually determine performance.
Airflow · Pressure · Load · Medium
How to Use the Selection Center
Four Steps From Requirement to Configuration
02 — Operating Conditions
Performance changes with the duty environment
Temperature
Pressure
Humidity
Medium
Water quality
Contaminant
Installation
Electrical
03 — Narrow the Range
Use the duty data to identify
- Product family
- Size
- Performance range
- Material
- Motor
- Pressure class
- Filter grade
- Control option
04 — Confirm Configuration
Check against the actual project before ordering
Especially important for smoke-exhaust equipment, explosion-proof products, high-efficiency filtration, chemical filtration, pressure equipment, and non-standard configurations.
Fan Selection
Start With Airflow and Pressure
A fan cannot be selected correctly from airflow alone. The same fan will operate at different airflow depending on the resistance of the system connected to it.
Required Airflow + Required Pressure → Fan Duty Point
YONGFAN’s current fan documentation repeatedly states that final model selection is confirmed against project airflow, static pressure and duty conditions.
Duty point, not free-air volume
Fan Duty Inputs
Seven parameters that actually determine the fan
Step 1 — Required Airflow
How much air must the fan move?
Provide design airflow in m³/h or m³/s.
- Ventilation calculations
- Air-change requirements
- Process exhaust demand
- Smoke-control design
- Heat-removal calculations
- Tunnel ventilation calculations
If only room dimensions and air-change rate are available, airflow can first be determined from the ventilation requirement.
Step 2 — Required Pressure
What resistance must the fan overcome?
Ductwork
Bends
Transitions
Filters
Dampers
Coils
Silencers
Louvers
Terminals
A fan that delivers the required airflow at 0 Pa may not deliver that airflow once installed in a real duct network. Always provide the design pressure where possible.
Step 3 — Operating Temperature
Standard ventilation or special duty?
Confirm the normal air temperature. Special applications may include hot process exhaust, boiler rooms, smoke exhaust and industrial process air.
Some YONGFAN fan families are available in configurations for elevated temperature or fire/smoke duty, but applicability must be confirmed by model and configuration.
Step 4 — Air Condition
What is in the airstream?
Clean
Dusty
Humid
Corrosive
Greasy
Chemically contaminated
Potentially explosive
This may affect fan architecture, motor position, material, surface protection and explosion-proof requirement. YONGFAN’s bifurcated T35-11 / BT35-11 architecture keeps the motor outside the main airstream and is documented for hot, corrosive, dusty and hazardous applications.
Step 5 — Installation Type
Where will the fan sit in the system?
- In-line duct mounted
- Wall mounted
- Roof mounted
- Cabinet mounted
- Free inlet / discharge
- Tunnel mounted
- Underground
Installation affects both the appropriate fan family and the actual system losses.
Step 6 & 7 — Noise & Electrical
Occupied-area targets and motor data
Noise: hotels, hospitals, offices and schools may prioritize acoustic performance more strongly than industrial process areas. Provide the project noise target where available.
Electrical: voltage, frequency, phase, motor type, speed, control method. Where applicable: VFD, dual-speed, explosion-proof motor, high-temperature configuration.
Which Fan Architecture?
Match the machine to the duty, not the catalogue photo
Axial Fan
High airflow + relatively low/moderate pressure
Typical applications: general ventilation, exhaust, large-volume air movement.
Mixed-Flow Fan
Compact installation + more pressure than conventional axial
Consider when the system needs extra pressure capability without a large centrifugal footprint.
Centrifugal Fan
Higher system resistance
Consider when the project has more demanding duct pressure requirements.
Roof Fan
Direct roof discharge
Consider when exhaust is discharged directly through the roof.
Bifurcated Fan
Motor outside the handled airstream
Consider for hot, corrosive, dusty or hazardous air where the motor should remain outside the airstream.
Tunnel Jet Fan
Thrust, not ordinary duct static pressure
Depends on effective thrust, tunnel air velocity, geometry, traffic, pollutant concentration and fire strategy. YONGFAN’s SDS/SDS(R) documentation specifies selection against project thrust calculations.
Fan Selection Data Checklist
Send the duty, not only a model number
- Airflow
- ______ m³/h
- Static / Total Pressure
- ______ Pa
- Temperature
- ______ °C
- Application
- ______
- Airstream Condition
- ______
- Noise Limit
- ______ dB(A)
- Installation
- ______
- Voltage / Frequency
- ______
- Special Duty
- Standard / Smoke Exhaust / Explosion-Proof
Checklist before model lock
Filter Selection
Select the Filtration System, Not Just the Grade
Filter selection requires a balance between air quality and air resistance. A filtration system with unnecessarily high resistance can increase the pressure requirement of the entire air system.
Selection should therefore begin with the filtration objective.
Efficiency × Resistance × Frame size
Step 1 — Primary Filtration
Larger particles and HVAC protection
Used for general HVAC protection and extending downstream filter life. Typical advantages: lower resistance, simple maintenance, washable options in selected types.
Step 1 — Medium Filtration
Protect the final high-efficiency stage
Used to remove finer particles and protect final high-efficiency filtration. YONGFAN’s F9 documentation positions medium filtration as an intermediate stage before HEPA terminals in pharmaceutical and electronics environments.
Step 1 — High-Efficiency
Where particulate control is critical
Applications can include cleanrooms, pharmaceutical environments, electronics and critical-process areas.
Step 2 — Required Efficiency
Follow the project specification
This may be expressed as project specification, filter class, ISO 16890 terminology, HEPA classification, or another applicable standard.
Do not automatically substitute one classification system for another. The required classification should follow the project specification.
Step 3 & 4 — Airflow & Resistance
Wrong airflow changes the whole system
A filter selected at the wrong airflow can produce different pressure drop, service behavior and system performance. Resistance affects fan selection. YONGFAN’s filtration material treats efficiency and initial resistance as key selection parameters.
Step 5 & 6 — Size & Environment
Especially for replacement and retrofit
Provide Width × Height × Depth for existing AHUs, filter banks and retrofit cleanrooms. Confirm temperature, humidity, dust loading, hygiene requirement and installation orientation. Non-standard dimensions may be considered where the product allows customization.
Step 7 — Final Filter or Multi-Stage System?
Consider the complete filtration sequence
Outdoor Air→
Primary→
Medium→
HEPA / Final
This can provide better lifecycle performance than expecting one final filter to handle the entire dust load.
If the target contaminant is dust / particles, use particulate filtration. If the target is H₂S / SO₂ / Cl₂ / NH₃ / VOCs / other gases, the project may require activated-carbon or dedicated gas-phase filtration. A higher-efficiency particle filter does not automatically solve a gas-contamination problem.
Particle or gas? Different systems.
Filter Selection Data Checklist
Send
- Airflow
- ______ m³/h
- Required Filter Stage
- ______
- Efficiency Requirement
- ______
- Initial Resistance Limit
- ______ Pa
- Dimensions
- ______ × ______ × ______ mm
- Operating Temperature
- ______ °C
- Humidity
- ______
- Application
- ______
- Downstream Filter
- ______
Stage · Grade · ΔP · Frame
Chemical Filtration Selection
Start With the Gas Analysis
Chemical filtration should not be selected by airflow alone. At minimum, identify the target gas, concentration, and whether you are protecting an indoor space or treating an exhaust stream. This distinction determines the system architecture.
H₂S
SO₂
Cl₂
NOx
NH₃
VOCs
Indoor Protection
Filtered fresh air, positive pressurization, recirculation purification, or combination systems. Typical environments: control rooms, server rooms, electrical rooms, instrument rooms.
Exhaust Treatment
If contaminated process air needs treatment before discharge, an exhaust-oriented system is required. The selection logic differs from corrosion-control systems used to protect rooms.
Protect a room, or treat exhaust?
Chemical Filtration Data Checklist
- Airflow
- ______ m³/h
- Room Volume
- ______ m³
- Target Gas
- ______
- Gas Concentration
- ______
- Application
- Indoor Protection / Exhaust Treatment
- Required Indoor Condition
- ______
- Installation Environment
- ______
Gas · Concentration · Duty
Heat Exchanger Selection
Start With the Thermal Duty
Not: “What connection size do I need?”
“What heat must be transferred, between which media, under what conditions?”
YONGFAN’s existing heat-exchange documentation uses heat source, temperatures, load and water quality as core selection inputs.
Load · ΔT · Pressure · Water quality
Step 1 — Heat Source
Confirm whether the primary side uses hot water, steam, or another applicable medium.
Step 2 — Primary Temperatures
Primary Inlet: ______ °C · Primary Outlet: ______ °C
Step 3 — Secondary Temperatures
Secondary Inlet: ______ °C · Secondary Outlet: ______ °C
Step 4 — Heat Load
Required capacity: ______ kW. If heat load is not available, flow and temperature difference may be used to help determine it.
Step 5 & 6 — Flow & Pressure
Provide primary and secondary design flows where available. Confirm system pressure. Existing YONGFAN documentation references 1.0, 1.6 and 2.5 MPa classes across applicable exchanger products.
Step 7 — Water / Medium Quality
Material selection can depend strongly on water chemistry: hard water, chloride content, corrosive media, seawater, process fluids.
SUS304
316
316L
316Ti
Titanium
Hastelloy
Copper
Which Heat Exchanger Type?
Plate
Compact footprint, efficient transfer, serviceable plates
Tube
When tube construction better matches medium, fouling or maintenance
U-Tube Storage
Heat transfer + hot-water storage both required
Floating-Coil Storage
Storage required, more demanding water quality, or service-favoring coil
Packaged Unit
Exchanger + pumps + controls as an integrated station
Architecture Rule
A storage-type exchanger may be more appropriate when peak demand buffering is required. A plate exchanger may be more suitable when compact heat transfer without storage is the main objective.
Heat Exchanger Selection Data Checklist
- Heat Source
- ______
- Primary Inlet / Outlet
- ______ / ______ °C
- Secondary Inlet / Outlet
- ______ / ______ °C
- Heat Load
- ______ kW
- Primary / Secondary Flow
- ______ / ______ m³/h
- Working Pressure
- ______ MPa
- Medium / Water Quality
- ______
- Storage Required
- Yes / No
- Available Space
- ______
kW · °C · MPa · Material
Valve & Hydronic Selection
Start With Function, Not Pipe Size
DN tells you the connection size. It does not tell you what the component must do. First determine the function.
Function first. DN second.
I Need to Control Room Temperature
Thermostat + Actuator + Control Valve
Depending on the terminal system. Confirm system type, control logic, valve arrangement and voltage.
I Need Automatic Water-Flow Control
Motorized Control Valves
Selection may require DN, flow, differential pressure, control method and actuator voltage.
I Need Hydronic Balancing
Balancing Valves
When the objective is to distribute design flow correctly between circuits.
I Need Pressure / Hydraulic Control
Hydraulic Control Valves
Depending on the required function.
I Need Pressure Stabilization
Pressure Stabilizing & Expansion Equipment
Confirm system volume, static pressure, working pressure, water temperature and expansion requirement.
I Need Water Supply
VFD or Non-Negative-Pressure Water Supply
Depending on available incoming pressure, required flow, required head and demand variation.
I Need Water Distribution
Distributors / Collectors
Confirm total flow, branch quantity, branch sizes and working pressure.
I Need Water Treatment
Define the water-quality problem first
Confirm water-quality problem, pipe diameter, flow, temperature and installation condition before selecting treatment equipment.
Valve & Hydronic Data Checklist
- Function
- ______
- DN / Pipe Size
- ______
- Flow
- ______ m³/h
- Head / Differential Pressure
- ______
- Working Pressure
- ______ MPa
- Temperature
- ______ °C
- System Volume
- ______ m³
- Voltage
- ______
- Control Method
- ______
- Existing Product / Drawing
- ______
Function · Flow · Head · Volume
When Online Selection Is Not Enough
Ask for Engineering Review When:
- The duty is outside the standard range
- The operating temperature is unusual
- The atmosphere is hazardous
- The medium is corrosive
- The equipment is pressure-bearing
- The project has strict certification requirements
- The installation dimensions are fixed
- Several products need to operate as one package
- The product is intended for fire or life-safety service
In these situations, use the Selection Center to organize the data, then send it to YONGFAN for final review.
From Selection to Technical Documents
After the product is identified
Product Page
Review the product range and technical characteristics.
Download Center
Access available datasheets, drawings, manuals, certificates and supporting technical files.
Technical Support
Request clarification where project-specific confirmation is required.
Send Us Your Selection Data
No Final Model Required
You can send an equipment schedule, BOQ, drawings, existing datasheet, or simply complete the relevant parameter list above. YONGFAN can then help determine:
Product Family→
Model Range→
Configuration→
Additional Data→
Final Confirmation
Equipment Schedule
BOQ
Drawings
Existing Datasheet
Fan Checklist
Filter Checklist
Heat Exchanger Checklist
Hydronic Checklist
Chemical Filtration Checklist