Central Air Conditioning system Direct expansion (DX) type

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Holtop Air Handling Fresh Air Purification Heat Recovery Ventilation Products Factory

DX Type Air Handling Units offered feature precision construction standards and allow air cooled direct expansion conditioning support. The equipment comprises indoor unit and outdoor unit support and allow between them direct connection without requirement of any water system process. Further, the AHU offers clean energy saving solution as desired by the customers. Some of its features include latest efficient design.

Holtop Suspended Ceiling DX Type AHU Direct Expansion Treated Fresh Air handling Unit

Combined with core technology of HOLTOP AHU, DX (Direct Expansion) coil AHU provide both AHU and outdoor condensing unit. It’s an flexible and simple solution for all building area, such as mall, office,Cinema,School etc.

Long piping design The pipe connection length between indoor unit and outdoor unit can reach 50m, and the maximum drop can reach 25m. The indoor unit and outdoor unit can be installed on site more flexibly.
Efficient refrigerant heat exchange flow pathEfficient two-in-one refrigerant confluence technology improves the liquid phase flow rate of the refrigerant, improves the overall heat transfer coefficient of the heat exchanger, and improves super cooling and strengthens the refrigerant transmission distance.
High efficient heat exchange fins The innovative high-efficiency low-pressure loss window fins are made of hydrophilic membrane aluminum, which can improve the heat transfer wet film heat transfer coefficient and improve the overall heat exchange performance of the unit.
Comfort Control SystemThe wire controller is simple and convenient, flexible in application, and widely used in small and medium-sized office-level business spaces.
Functional control system Building systems based on the MODBUS protocol can be directly connected to the centralized control system through the MODBUS communication interface standard on the unit, no need to access conversion equipment, and are suitable for large and medium sized air-conditioning locations. Dual Temperature Sensors Innovative design with two temperature sensors, one at return vent, and one at the control panel, to detect the indoor temperature around the room, and make sure the hot wind(winter heating mode) would be sent to each corner of the room uniformly.
Control network topology diagram
Advanced silencing technology, More quiet and reliable operation
High efficient heat exchanger
New U-shaped heat exchanger As the core element of the refrigeration system, the heat exchanger directly determines whether the air conditioning system is reliable and energy-saving. Holtop combined with many years of outdoor unit development experience and market demand, developed a new generation of U-shaped heat exchanger. Such advanced and efficient heat exchangers have made Holtop's HFM series highly efficient and energy-saving, and also meeting the Holtop Vision of "making air treatment more healthy and energy-saving". The airflow of the fan is effectively used, and the heat exchange area is fully expanded without increasing the space of the unit, and the heat exchange efficiency is greatly improved. Compact structure, high strength, more convenient for installation and maintenance. The use of hydrophilic membrane aluminum fins improves the heat transfer wet film heat transfer coefficient and provides the overall heat transfer coefficient of the unit.	U-shaped heat exchanger structureThe copper tube adopts φ7.94 thread copper tube, the flow rate is moderate, and the comprehensive performance of heat exchange defrosting is optimal. The distance between φ7 copper tubes is the smallest, the frost has a great influence on the heat transfer, and the frost layer is thick, which affects the defrosting time. The diameter of φ9.52 is large, the disturbance to the heat transfer boundary layer is small, and the heat transfer efficiency is low.
Green Refrigerant The Holtop HFM series SUSPENDED DX AIR HANDLING UNIT uses R410A as refrigerant, with zero ODP, to avoid damage to the ozone layer and at the same time, greatly improve cooling capacity.
Easy maintenance The whole unit uses frameless foaming boards to construct, and self-tapping screws to connect these boards, making it very easy to be disassembled for maintenance.
High ESP Design – Easy Selection The indoor unit generates a high ESP, making it possible to cover the whole area to avoid uneven distribution of temperature. Such feature makes solution and design much easier.
Wide Operation Temperature RangeEven at 15°C, the cooling function can be activated normally; Heating function can be activated at -10°C in winter.
Both return air and fresh air indoor units availableThe HFM outdoor unit can work with both return air and fresh air Indoor unit, to meet different customers’ needs.

Compared with other centralized and semi-centralized air handling systems, the DX Coil Air Handling system layout is simpler and more flexible, so it is widely used in shopping malls, office buildings, apartments, theaters, schools and other places.