In the HVAC industry and air-conditioning water system, we often hear FCU, AHU, PAU, RCU, MAU, FU, HRV, FAU, OAC and EAF, etc. - a series of strange nouns. So, what do the concepts represented by these letters mean? What is the difference between them? Recirculate the air in the room where the air is cooled (heated) after passing through the cold water (hot water) coil to keep the room temperature constant. It mainly relies on the forced action of the fan to heat the air when it passes through the surface of the heater, thus strengthening the convective heat exchanger between the radiator and the air, which can quickly heat the air in the room.
2, AHU (full name: Air Handling Units, air handling unit)
air handling unit , also known as air conditioning box, wind cabinet. It mainly relies on the rotation of the fan to drive the indoor air to exchange heat with the internal coil of the unit, and to filter the impurities in the air, so as to maintain the indoor temperature, humidity and air cleanliness by controlling the outlet air temperature and air volume. The air handling unit with the fresh air function also performs heat and humidity treatment and filtering functions on the air including fresh air or return air. At present, air handling units mainly have several forms such as ceiling type, vertical type, horizontal type and combined type. Among them, the ceiling-type air handling unit is also called a hanging cabinet; the combined air handling unit is also called a combined wind cabinet or a cabinet.
3, HRV full heat exchanger
HRV, full name: Heat Reclaim Ventilation, Chinese name: energy recovery ventilation system. The Daikin air conditioner was invented in 1992 and is now called " full heat exchanger ".This type of air conditioner recovers lost heat energy through ventilation equipment, reducing the load on the air conditioner while maintaining a comfortable and fresh environment. In addition, HRV can be used in conjunction with VRV system , commercial split systems and other air conditioning systems, and can automatically switch ventilation modes to further improve energy saving effects.
4, FAU (full name: Fresh Air Unit, fresh air unit )
FAU fresh air unit provides a kind of air conditioning equipment for fresh air, which is divided into household and commercial use.
Working principle: Fresh air is drawn from the outside and sent to the room through the fan after dust removal, dehumidification (or humidification), cooling (or heating) and other treatments, and replaces the original indoor air when it enters the indoor space. The difference between AHU air handling unit and FAU fresh air unit: AHU not only includes the fresh air condition, but also includes the return air condition; FAU fresh air unit mainly refers to the air handling unit with fresh air condition. In a way, it is the relationship between the former and the latter.
5, PAU (full name: Pre-Cooling Air Unit, pre-cooling air-conditioning unit)
pre-cooling air-conditioning unit is generally used in conjunction with the fan coil FCU, the function is to pre-treat the outdoor fresh air, and then send it to the fan coil ( FCU).
6, RCU (full name: Recycled airhandling Unit, recirculating air conditioning box)
Recycling airhandling unit is also called indoor air circulation unit, mainly sucks and discharges indoor air to ensure indoor air circulation.
7, MAU (full name: Make-up Air Unit, fresh air unit)
brand new air unit is an air conditioning equipment that provides fresh air. In terms of function, according to the requirements of the use environment, it can achieve constant temperature and humidity or simply provide fresh air.The working principle is to extract fresh air outside. After dust removal, dehumidification (or humidification), cooling (or heating) and other treatments, it is sent to the room through the fan, and the original air in the room is replaced when it enters the indoor space. Of course, the functions mentioned above must be determined according to the needs of the use environment. The more complete the functions, the higher the cost.
8, DCC (full name: Dry Cooling Coil, dry cooling coil)
dry cooling coil (referred to as dry coil or dry cooling coil), is used to eliminate indoor sensible heat .
9, HEPA high-efficiency filter
high-efficiency filter refers to the filter screen that meets the HEPA standard, and the effective rate for 0.1 micron and 0.3 micron reaches 99.998%. The characteristic of HEPA mesh is that air can pass through, but fine particles cannot pass through. It can remove more than 99.7% of particles with a diameter of 0.3 microns (1/200 of the hair diameter), and is the most effective filter medium for pollutants such as smoke, dust, and bacteria. It is an internationally recognized high-efficiency filter material. It has been widely used in high-clean places such as operating rooms, animal laboratories, crystal experiments and aviation.
10, FFU (full name: Fan Filter Units, fan filter unit)
fan filter unit is a terminal purification that combines fans and filters (high efficiency filter (HEPA) or ultra high efficiency filter (ULPA)) to form its own power supply equipment. To be precise, it is a modular terminal air supply device with its own power and filtering function. The fan sucks air from the top of the FFU and filters it through HEPA, and the filtered clean air is evenly sent out at the wind speed of 0.45m/s±20% on the entire air outlet surface.
11, OAC external air treatment unit
OAC external air treatment unit is called in Japan, it is used for feeding into closed workshops, which is equivalent to domestic fresh air treatment unit MAU or FAU.
12, EAF (full name: Exhaust Air Fan, exhaust fan )
EAF air conditioning exhaust fan, mainly used in public areas of the floor, such as corridors, stair front rooms, etc.
