Advantages and Disadvantages of Different Kinds of Fresh Air Systems

PublishTime: 2019-06-20 08:36:04

As the city pollution is getting serious and living quality is improving, fresh air systems are also upgrading, coming in various functions. There’re mainly four types of fresh air systems: unidirectional airflow, self-balancing, bidirectional flow, total heat exchanging. Let’s have a detail look at them all:


unidirectional airflow

With a simple design, it’s the original form of fresh air systems, which only intake or exhaust the air. There’s no need to wash the tube as it serves as an outlet, which has no effect on the air quality of the new wind. Therefore, it has no maintenance cost.



Self-balancing fresh air ventilators, which are equipped with balancing devices on each tube of the intake, are able to keep constant air volume. With separated intake tubes, it’s not necessary to install a splitter, and every room can get balanced air volume. It’s easy to install and suits simple-furnished houses. However, it’s not a perfect way of filtering, and it can’t recycle the energy.


bidirectional flow

Bidirectional flow fresh air ventilators contain simple filtrating devices, which can filtrate some dust. However, the tubes need cleaning, and it’s difficult to clean. Compared with the natural unidirectional flow, it has an intake system and an exhaust system, which are both mechanically operated to form a bidirectional flow, and its flowing direction and device locations can be individually designed and arranged.


total heat exchanging

Compared with bidirectional flow ventilators, Total heat exchanging fresh air system has an energy recovery ventilator (ERV) between the intake and the outlet, which recycles sensible heat, as well as latent heat. It recovers the heat with the temperature and the partial vapor pressure difference between the intake flow and the outlet flow. In this way, it recycles the coolness or heat, and reduce the energy loss of cooling load or thermal load, which is unachievable with bidirectional flow systems. Total heat exchanging system is able to turn the intake air up or down, which decrease the load of air conditionals and is more energy saving.