The differences between medical purification air conditioning units and ordinary air conditioning units

The medical cleanroom air conditioning is a closed air handling equipment composed of multiple functional sections such as the air intake section (air mixing section), coarse and medium-efficiency filtration section, fan section, sub-high-efficiency filtration section, cooling and heating treatment section, humidification section, and air outlet section. The medical purification air conditioning unit equipment relies on the centrally supplied chilled and hot water, has high requirements for airtightness, and usually operates with the assistance of an automatic control system.

The air conditioning unit for clean operating rooms is a special equipment that directly supplies treated air to clean operating rooms and the areas serving them (or other similar places with biological control requirements). It includes refrigeration, heating, humidification, and ventilation devices, as well as special measures to control the growth of microorganisms. It can be a unitary unit or a split unit (excluding packaged air conditioning units).

In terms of structural forms, there are five major series: horizontal structure, ceiling-mounted structure, fresh air structure, rooftop structure, and fan coil structure. In terms of systems, there are chilled water type, direct cooling type, and heat pump type units for users to choose from.

Characteristics of Medical Purification Air Conditioning Units

The commonly mentioned purification air conditioning units use water as the carrier of cold and heat sources and are composed of purification fresh air units and purification circulation units, etc. They can be used in air purification systems of any purification level. The medical air conditioning purification system (such as a clean operating room) usually adopts a semi-centralized air conditioning purification system with centralized fresh air treatment and decentralized treatment in each room. The centralized fresh air conditioning unit is used to treat fresh air, emphasizing its final treatment state point, and it is hoped that the fresh air can bear the indoor moisture load. The air adjusted by the decentralized circulation units in each room controls the indoor temperature, achieving independent control of temperature and humidity.

Requirements for Medical Purification Air Conditioning Units

For the purification fresh air unit, it is advisable to give priority to the air filtration measures that can ensure the collection of clean fresh air to protect the air filters at all levels inside the equipment and the heat exchange equipment. According to the local ambient air conditions, a series combination form of one, two, or three filters can be adopted. When the annual average value of inhalable particulate matter PM10 outdoors does not exceed 0.10mg/m³, at least two levels of filtration, namely coarse and medium efficiency, should be set at the fresh air intake; when the annual average value of outdoor PM10 exceeds 0.10mg/m³, a high-efficiency medium filter should be added.

The cooling and heating capacity, air supply volume, and total fan pressure or the external static pressure of the purification fresh air unit and the circulation unit should have sufficient margins according to the climatic characteristics of the location, the cleanliness of the cleanroom, and the pressure difference relative to the adjacent rooms. The control program, sensors, actuators, etc. of the purification fresh air unit and the circulation unit should meet the accuracy requirements of temperature and humidity control, and the air volume and cooling and heating capacity of the unit should be continuously adjustable. Before leaving the factory, the purification fresh air unit and the circulation unit should undergo thermal performance and tightness tests and issue a certificate of conformity. When maintaining a static pressure of 500Pa, the air leakage rate of the unit should not be greater than 1% for Class I and Class II clean places, and the sampling inspection rate is 100%; for other clean places, it should not be greater than 2%, and the sampling inspection rate should not be less than 30% and at least 1 unit. When the unit must be disassembled for transportation due to site conditions, it should be assembled and re-sealed on the installation site, and the air leakage rate test should be carried out. The control index and sampling inspection rate of the air leakage rate are the same as the requirements before leaving the factory. When installing the purification fresh air unit and the circulation unit, vibration isolation should be considered. The unit should be kept horizontal, and effective measures should be taken to prevent horizontal displacement. The connection between the unit and the external electrical pipelines, water pipelines, and air ducts should all adopt flexible connections, and the electrical pipelines must be kept airtight. When installing the purification fresh air unit and the circulation unit, the drainage of condensed water and steam condensate water in different sections should all adopt independent indirect drainage with water seals, and it should ensure that the unit can drain smoothly within 5 minutes when put into operation under summer operating conditions. When using the fresh air humidification method of centralized pre-treatment to supply fresh air to multiple circulation units, in order to ensure the humidity index, the surface air cooler and humidifier of the unit should consider sufficient humidity adjustment capacity. In order to ensure that the indoor humidity control is met, it is required to install a direct expansion refrigeration unit or a special chiller for low-temperature chilled water in the fresh air purification air conditioning unit. For the all-air system that uses fresh air to undertake the standby air supply, dehumidification measures should be taken to control the humidity of the fresh air supply.