Views: 598 Author: Doris Jiao Publish Time: 2025-09-11 Origin: Site
Air handling units (AHUs) are the core equipment of air conditioning systems. It can cooling, heating, humidify, and filter air according to different application scenarios, and is widely used in various public and commercial spaces. AHUs are mainly classified into four types: ceiling-mounted, jet-type, horizontal, and vertical. Although their core functions are consistent, the classification is essentially based on matching the installation space with functional requirements.
This document provides a detailed explanation of AHU classifications, core configurations, operating parameters, performance advantages, and application scenarios, serving as a reference for user selection and application.
1. Installation Method
Ceiling - mounted air handling units adopt a hoisting installation design. It has a compact structure and small size, does not occupy floor space, and only needs to be fixed inside the building ceiling using special hoisting brackets (ensure the ceiling load-bearing capacity is at least 1.2 times the unit weight).
During installation, sufficient maintenance space needs to be reserved (usually 300–500 mm around the unit). The ceiling interior should be well-ventilated to prevent heat buildup during operation. The unit’s inlet and outlet ducts need to be accurately connected to the duct system inside the ceiling to ensure airtightness and reduce air leakage.
2. Air Supply Distance
Due to its compact size and moderate fan power and pressure, the air supply distance is typically 7.5–40 meters. This type of unit is suitable for short-distance air supply and is usually used with local indoor air ducts or air diffusers to achieve precise air treatment in small areas (e.g., small offices, meeting rooms, hotel guest rooms), avoiding increased air resistance, energy consumption, and temperature loss caused by long-distance air supply.
3. Key Advantages and Application Scenarios
Its main advantage is saving floor space and offering flexible installation, especially suitable for areas with limited floor space.
Applicable scenarios include hotel guest rooms, small offices, hospital wards, library reading rooms, and other small or decentralized air treatment areas.
1. Installation Method
Jet AHUs can be installed in two ways: ceiling and floor-standing. The ceiling installation is similar to ceiling AHUs, but the unit body is equipped with a special jet air outlet. The floor installation form requires placing the unit in a flat floor area (with a damping pad such as a rubber cushion to reduce vibration), or elevated 100–200 mm above the ground for easy cleaning and maintenance.
During installation, attention should be paid to the orientation of the jet air outlet. The angle should be adjusted according to the indoor space layout and air supply requirements (0 - 30°angle adjustment can be achieved) to ensure that the jet air flow can cover the target area. At the same time, flexible pipes should be used for the connection between the unit and the air duct to reduce the impact of vibration on the air duct and ensure stable air supply.
2. Air Supply Distance
The core advantage of jet AHUs is long-distance air supply. Using special jet airflow technology, high-pressure airflow creates a jet effect that overcomes air resistance, allowing air supply distances of 20–50 meters, with some large models reaching over 60 meters. These units do not require complex duct systems and can deliver conditioned air directly through jet nozzles, reducing duct investment and resistance losses.
3. Key Advantages and Application Scenarios
Advantages include long air supply distance, uniform airflow distribution, and reduced ductwork, lowering installation costs and space usage.
Applicable scenarios include large shopping malls, supermarkets, gymnasiums, exhibition halls, and train station waiting halls—large, high-ceiling spaces (typically ≥4 meters) requiring efficient air circulation and temperature control.
1. Installation Method
Horizontal AHUs are installed on the floor in a horizontal layout. They need to be placed on a flat surface (with cement leveling or steel base) to ensure stable operation.
Units can be customized in size and are typically modular, allowing for combination of different sections (e.g., filter, cooling, heating, humidification). Duct connections usually use flanges with sealing gaskets (e.g., temperature-resistant rubber) to ensure airtightness. Sufficient maintenance space must be reserved (500–800 mm on both sides, 400–600 mm on top).
2. Air Supply Distance
With larger fan power and higher pressure, and matched with proper duct design, the air supply distance can reach 27–55 meters. These units are suitable for medium to long-distance air supply and can distribute conditioned air to multiple rooms or large areas with stable airflow and high temperature control accuracy (±1°C).
3. Key Advantages and Application Scenarios
Advantages include a wide airflow range (Ruidong horizontal AHUs: 2000–50000 m³/h), full functional sections, and high heat exchange efficiency, meeting complex air treatment needs.
Applicable scenarios include large offices, hotel lobbies, hospital outpatient buildings, library halls, and shopping mall floors—medium to large centralized air treatment areas.
1. Installation Method
Vertical AHUs are installed upright on the floor, occupying a small footprint (1/3 to 1/2 of horizontal units), suitable for narrow spaces like corners, equipment rooms, or corridor sides. The unit must be placed on a level surface, with adjustable feet (50–100 mm) for leveling to avoid vibration.
Air inlet and outlet directions are flexible—side inlet/top outlet or bottom outlet—depending on site requirements. Ducts are connected via flanged seals to prevent leakage. Maintenance doors are located on the front or side, requiring only 200–300 mm of top clearance.
2. Air Supply Distance
The air supply distance is between ceiling-mounted and horizontal types, typically 27–55 meters. Due to the taller structure and higher fan placement, airflow can be optimized using outlet designs (e.g., double-layer louvers, diffusers) to effectively cover mid-level spaces, suitable for medium-sized areas.
3. Key Advantages and Application Scenarios
Advantages include small footprint, flexible installation, and full functionality, enabling high airflow treatment in limited space.
Applicable scenarios include equipment rooms next to hotel corridors, auxiliary areas in small malls, hospital corridors, and areas near pantries or restrooms in office buildings.
1. Humidification and Filtration Configuration
(1) Humidification Function: Without changing the unit size, a wet film humidification module can be added. It uses natural evaporation, produces no white mist, and adjusts humidity automatically based on indoor needs (specifically matched according to the unit air volume).
(2) Filtration Configuration:
l Standard Filter: Return air inlet equipped with nylon mesh filter, a primary filter with filtration precision of 1–10 μm, effective for large dust particles, easy to clean and replace.
l Optional Filter: Primary panel filter (40–60% efficiency for ≥5.0 μm particles) can be selected. For higher cleanliness, medium or high-efficiency filters are available.
2. Cooling Coil Row Options
Cooling (or heating) coils are available in 4-row, 6-row, and 8-row configurations:
l 4 - row pipes: Smaller heat exchange area, suitable for small space with low heat exchange demand, compact and energy-efficient.
l 6 - row pipes: Moderate area, mainstream configuration, suitable for most cooling/heating needs (e.g., offices, hotel lobbies), balancing heat exchange efficiency and energy consumption.
l 8 - row pipes: Largest area, highest efficiency, suitable for high heat exchange demand scenarios (e.g., cold climates, high-heat equipment rooms, high-temperature/humidity fresh air). It can quickly adjust the air temperature and ensure the stability of the indoor temperature.
3. Operating Parameter Standards
Air handling units are divided into two operation modes: return air mode and fresh air mode:
Return Air Mode (mainly indoor air, ≤30% fresh air):
l Cooling: Chilled water 7°C/12°C, inlet air 27°C/19.5°C DB/WB, cooling capacity 10.5–377.9 kW.
l Heating: Hot water 60°C, inlet air 21°C DB, heating capacity 17.2–619.8 kW.
Fresh Air Mode (Fresh Air Mode (mainly handles outdoor fresh air, with a high proportion of fresh air, generally ≥ 70%, or even 100% fresh air):
l Cooling: Chilled water 7°C/12°C, inlet air 35°C/28°C DB/WB.
l Heating: Hot water 60°C, inlet air 7°C DB.
1. Efficient Heat Exchange:High - Quality Surface Coolers of Ruidong Self Made
Ruidong’s proprietary cooling coils use high-quality copper tubes with hydrophilic aluminum fins, manufactured using mechanical expansion for tight contact and high efficiency.
Coils are tested at 2.0 MPa for leaks. The 0.12 mm hydrophilic aluminum foil prevents water buildup and corrosion, extending service life.
2. Stable and Low-Noise Operation
l Dual-inlet centrifugal fans with dynamic and static balance testing for smooth, quiet operation.
l Low-vibration design reduces noise transmission by over 30% and prevents structural impact.
l Internationally branded bearings ensure long life and low maintenance.
3. Durable and Safe Structure
l Aluminum alloy frame with no thermal bridge, high strength, lightweight, and corrosion-resistant.
l Double-sided color steel panels with high-density polyurethane foam insulation prevent condensation and energy loss.
4. Easy Maintenance
l Self-tightening access door locks ensure airtightness and allow quick access for filter replacement or coil cleaning.
l CRAA certified, ensuring reliable performance and quality for demanding applications.
Thank you for choosing Ruidong Group. We are committed to delivering efficient, reliable, and energy-saving air handling solutions. If you have any questions during product selection, system design, or installation, please don’t hesitate to contact us. Our dedicated team is ready to provide expert support and help you create a comfortable, healthy, and sustainable indoor environment.
