Product

Direct Expansion (DX) Air Conditioning Unit

Unit Overview:
The Direct Expansion air conditioning system is an all-air system consisting solely of an outdoor unit and an indoor unit. It requires no auxiliary equipment such as water pumps, cooling towers, or fan coil units, nor does it need condensate drainage piping, making installation and operation extremely convenient. With no moving mechanical parts or water pipes indoors, users are free from concerns over noise or water leakage, and maintenance is straightforward. The unit can be installed on rooftops or outdoor open areas, eliminating the need for an equipment room and reducing initial investment. Since no secondary refrigerant is required, the system operates with high efficiency. The unit offers comprehensive functions, including air purification, dehumidification, humidification, cooling, heating, and fresh air volume adjustment. It is suitable for a wide range of applications, such as shopping malls, restaurants, entertainment venues, office buildings, conference halls, and general industrial workshops, as well as clean environments in industries like pharmaceuticals, food processing, electronics, chemicals, scientific research, and machinery.

Working Principle:

Cooling Mode:
The outdoor finned heat exchanger acts as the condenser, while the indoor finned heat exchanger serves as the evaporator. The high-temperature refrigerant gas discharged from the compressor condenses into liquid in the outdoor finned heat exchanger, then passes through the expansion valve, where it is throttled and depressurized into a low-temperature gas-liquid mixture. This mixture flows into the indoor finned heat exchanger, absorbs heat, evaporates, and returns to the compressor, completing a refrigeration cycle. Simultaneously, the return air (or fresh air) from indoors passes through the indoor finned heat exchanger (acting as the evaporator) and is cooled. The treated cool air is then delivered back indoors by the indoor fan.

Heating Mode:
The outdoor finned heat exchanger acts as the evaporator, while the indoor finned heat exchanger serves as the condenser. The high-temperature refrigerant gas discharged from the compressor condenses into liquid in the indoor finned heat exchanger, then passes through the expansion valve, where it is throttled and depressurized into a low-temperature gas mixture. This mixture flows into the outdoor finned heat exchanger, absorbs heat, evaporates, and returns to the compressor, completing a refrigeration cycle. Simultaneously, the return air (or fresh air) from indoors passes through the indoor finned heat exchanger (acting as the condenser) and is heated. The treated warm air is then delivered back indoors by the indoor fan.

Unit Features:

1. The DX air handling unit primarily consists of an air handling unit and an air-cooled compressor-condenser unit, directly connected by copper pipes through which refrigerant flows. Air is cooled by the evaporator and undergoes further treatment before being supplied indoors.

2. Wide Applicability:
   The product series includes constant humidity, cooling/heating, and heat pump models. Constant temperature and humidity units meet the requirements of environments with strict temperature and humidity control, cooling/heating units are suitable for comfort applications, and heat pump units offer dual functionality, reducing heating operation costs.

3. Cost Savings:
   The unit can be installed on rooftops or outdoor open areas, eliminating the need for an equipment room and saving valuable space. It requires no auxiliary equipment such as water pumps, cooling towers, or fan coil units, reducing initial investment.

4. Easy Installation:
   The unit requires no on-site refrigerant piping or cooling water piping. Once ductwork is connected and power is supplied, it is ready for use, saving on-site construction time and costs.

5. High Efficiency and Energy Savings:
   The unit is equipped with high-performance scroll or screw compressors, offering high volumetric efficiency and energy efficiency ratios. Screw compressors allow convenient four-step or stepless capacity adjustment, ensuring high efficiency under partial loads. Refrigeration components such as expansion valves, filters, and solenoid valves are sourced from reputable international brands (e.g., American, Italian). The system requires no secondary refrigerant, further enhancing efficiency.

6. Quiet Operation:
   The unit utilizes high-performance scroll or screw compressors, ensuring smooth and quiet operation. Installed outdoors, only ductwork is required indoors, minimizing indoor noise.

7. Unique Structure:
   The unit features an aluminum alloy frame with clean, aesthetically pleasing lines. The top panel is specially designed to prevent water ingress. Door panels are made of polyurethane foam or cold-rolled steel plates, ensuring excellent thermal insulation. The electrical box is sealed for safety, and power wiring is enclosed within it, eliminating concerns about roof leakage.

8. Safe Operation:
   The unit includes multiple protections, such as high pressure, low pressure, overload, short circuit, phase failure, overheating, and under-pressure protection, as well as fire damper interlock protection.

9. Intelligent Control:
   The unit is equipped with an advanced control panel, which can be paired with handheld controllers for convenient operation both outdoors and in indoor control rooms. The panel features an RS485 interface for remote control capability.

10. Easy Function Expansion:
    The unit is designed with multiple functional sections, allowing easy implementation of air cooling, dehumidification, heating, humidification, filtration, and fresh air exchange.

11. The unit integrates related functional sections into a single module, reducing the overall length and footprint without compromising functionality.

12. With an optional remote control box, the unit can be operated and controlled from indoors, eliminating the need for outdoor adjustments.

13. If residual pressure requirements are specified during ordering, different fans and motors can be selected to meet the demands of various applications.