DX air conditioning system is direct expansion air conditioners, to put it plainly, is that the unit itself has a compressor, because the liquid refrigerant in its refrigeration system directly evaporates (expands) in its evaporator coil to achieve the The air (that is, the air inside the air-conditioned room) absorbs heat and cools, so it has the name. "Direct Expansion Air Conditioning Unit" English is: Direct Expansion Air Conditioning Unit, shorthand: DX A / C or DX Air Conditioning Unit.
Direct expansion air-conditioning units include various forms of air-conditioning products, such as unit air conditioners, ceiling air conditioners, ceiling air duct machines, multi-line (also known as "one-to-multi" units, variable frequency multi-line, etc.), roof-type air conditioners Machines, including: dehumidifiers, precision air conditioners, etc.
Just hold one point firmly, that is: the direct expansion air-conditioning unit is the refrigerant to directly perform the heat exchange with the air to be processed, without secondary heat exchange in the middle, namely: refrigerant-air. The most common large-scale central air-conditioning system currently composed of chiller units and air-conditioning end units is different from direct-expansion air-conditioning units in that the heat exchange method is: refrigerant-water-air, that is, the refrigerant first The water absorbs heat to generate chilled water. The chilled water is then sent to the end units such as fan coils in the room through the pipeline. The fans in the unit circulate air to heat exchange the indoor air with the chilled water in the coils to generate "cool air". .
That is, the direct expansion air-conditioning unit is a "primary refrigerant" system.
According to the above analysis, it can be seen that: household air conditioners, including wall-mounted machines, cabinet machines, window machines, ceiling machines, etc. are all direct expansion air-conditioning units. In shopping malls, office buildings, and other occasions, the central air-conditioning system with a refrigeration station (refrigeration main room) is obviously a water system, and does not belong to the expansion air-conditioning unit.