Reason why the cooling capacity required for central air conditioning in the full fresh air mode is much greater than that in 100% recirculation mode mainly includes the following points:
Temperature and Humidity Difference: The full fresh air mode means that the air conditioning system entirely relies on the fresh air introduced from outdoors to regulate the indoor environment. This fresh air usually has a significant difference in temperature and humidity compared to the indoor air. Especially in summer, the outdoor air can be very hot and humid, requiring the air conditioning system to use more energy for cooling and dehumidification to achieve a comfortable indoor level.
Increased Air Handling Volume: In the full fresh air mode, the air conditioning system deals with external air that has not been temperature-regulated. In contrast, in recirculation mode, the air has already been partially cooled and treated, so less energy is required to further adjust it to the desired temperature.
Thermal Load Consideration: In full fresh air mode, the thermal load that the air conditioning system needs to consider includes the sensible and latent heat of the outdoor air, while recirculation mode mainly deals with the heat load generated indoors. The introduction of fresh air increases the total heat load that the air conditioning system needs to handle.
Air Quality Requirements: In some applications, such as hospitals, laboratories, or specific industrial environments, due to air quality requirements, more fresh air volume may be needed, directly increasing the workload of the cooling system.
Overall, the full fresh air mode requires the air conditioning system to handle more air with greater variations in temperature and humidity, leading to a significant increase in cooling capacity. To meet the comfort and air quality standards in this condition, the system design needs to consider a greater cooling capacity.
