As a relatively closed space, air circulation and passenger respiratory health are key considerations in the design and operation of elevator air conditioning. Elevator air conditioning uses multiple technical means and structural designs to maximize air quality while ensuring air circulation, creating a safe and comfortable riding environment for passengers.
Elevator air conditioning usually adopts the airflow mode of "upward delivery and downward return" or "side delivery and side return". Taking the common top air supply design as an example, the air outlet of the air conditioner is set at the top of the car, and the cold or hot air is blown out evenly through the blinds and diffused to the entire space along the wall or ceiling of the car, while the return air outlet is located at the bottom or lower side of the car. This design uses the difference in air density to form natural convection, avoiding discomfort caused by direct airflow to passengers, while ensuring that the air circulates in the car and reduces air retention in local areas. By optimizing the air duct shape and outlet angle through computational fluid dynamics (CFD) simulation, the uniformity of air flow distribution can be further improved to prevent the occurrence of airflow dead corners that lead to a decrease in air quality.
The filter device equipped with elevator air conditioning usually includes a multi-stage structure such as primary filtration and medium efficiency filtration. The primary filter mainly intercepts dust, hair, large particles of pollutants, etc. It is generally made of washable nylon mesh or metal mesh for easy regular maintenance; the medium-efficiency filter targets PM2.5, pollen, bacteria and other tiny particles. Some high-end air conditioners will also be equipped with activated carbon filters or photocatalyst filters to absorb harmful gases such as formaldehyde and odor, and decompose microorganisms in the air through photocatalytic reactions. These filter components work together to effectively purify the air entering the air conditioning system and reduce the risk of passengers inhaling pollutants. For example, in office buildings or hospital elevators with dense traffic, high-efficiency filtration systems can reduce the total number of bacterial colonies in the air by more than 60%, significantly improving the air quality in the cabin.
In order to avoid the increase of carbon dioxide concentration due to long-term circulation of air in the cabin, elevator air conditioning needs to design a reasonable fresh air introduction system. Some elevators will open a fresh air inlet in the machine room or shaft, and introduce outdoor fresh air into the cabin at a certain proportion through a fan, and at the same time, exhaust the same volume of dirty air through the exhaust device, forming a "fresh air-return air" mixed mode. The design of fresh air volume must comply with building regulations, usually calculated at 10-15 cubic meters per person per hour, to ensure that the carbon dioxide concentration in the car is less than 1000ppm. During special periods such as epidemics, some elevators can also temporarily adjust the fresh air ratio, or even start the fresh air operation mode to completely cut off the possibility of cross-infection of the air.
In a closed environment, the air conditioning system itself may become a breeding ground for microorganisms, so elevator air conditioning needs to use antibacterial materials and antibacterial technology. For example, the evaporator surface is sprayed with an antibacterial coating to inhibit the growth of bacteria and mold; the condensate tray is designed to be inclined and a drainage pump is installed to avoid water accumulation; the air conditioning pipeline is regularly exposed to ultraviolet light or ozone sterilization to destroy the DNA structure of microorganisms. Some smart elevator air conditioning are also equipped with air quality sensors to monitor the concentration of microorganisms in the air in real time. When the value exceeds the standard, the sterilization program is automatically started to ensure the hygienic safety of air supply from the air conditioner.
Elevator air conditioning creates a suitable microclimate environment by precisely controlling temperature and humidity. In summer, the temperature is maintained at 24-26℃ and the relative humidity is controlled at 40%-60%, which can not only avoid the accelerated metabolism and increased breathing rate caused by high temperature and stuffiness, but also inhibit the growth of mold; in winter, the temperature is maintained at 18-22℃, and the humidity is appropriately increased through a humidifier to prevent the air from being too dry and causing discomfort to the respiratory mucosa. A stable temperature and humidity environment can also reduce passengers' sneezing, coughing and other behaviors caused by cold and hot stimulation, reduce the risk of droplet transmission, and indirectly ensure respiratory health.
Modern elevator air conditioning is mostly equipped with intelligent monitoring modules to collect air quality data in the cabin in real time (such as PM2.5 concentration, carbon dioxide concentration, volatile organic matter content, etc.), and transmit it to the property management center through the Internet of Things platform. When an indicator exceeds the standard, the system automatically issues an early warning to prompt maintenance personnel to clean or replace the filter device and check the operating status of the fresh air system. Regular professional maintenance (such as cleaning the filter every quarter, checking the air tightness of the air conditioning pipeline every year, etc.) can also ensure that various air treatment functions continue to be effective, avoiding poor air circulation or reduced purification capacity due to aging equipment.
In places such as hospitals and laboratories that have extremely high requirements for air quality, elevator air conditioning will be upgraded to a medical-grade purification system, adding a high-efficiency filter (HEPA) and an electrostatic dust removal device, which can filter more than 99.97% of 0.3-micron particles, and equipped with an independent exhaust duct to prevent the spread of germs to other areas; in the hot and humid southern regions, elevator air conditioning will strengthen the dehumidification function to prevent condensation from accumulating and affecting equipment operation, while reducing mold growth; in the cold northern winter regions, the air conditioning system must have a cold wind prevention design to ensure that preheated air is delivered first when starting, to prevent passengers from inhaling cold air and causing respiratory discomfort.
Through the above-mentioned multi-dimensional technical means and refined design, elevator air conditioning has built a complete air circulation and purification system in a limited space. From airflow organization to filtration and sterilization, from temperature and humidity control to intelligent maintenance, every link is closely centered on the respiratory health of passengers, which not only meets the basic environmental comfort needs, but also plays an important role in public health and safety. With the continuous advancement of technology, elevator air conditioning will incorporate more intelligent and green air treatment technologies in the future to provide stronger protection for the safety and health of the elevator environment.
