Total heat exchange and two-way flow are common terms in the field of building ventilation. These two systems have different characteristics and functions while realizing indoor ventilation. The differences between the two are explained in detail below.

Definition and principle
1. Full heat exchange system:
A total heat exchanger is a ventilation device capable of energy recovery. It saves energy by carrying out heat exchange between indoor and outdoor air. Full heat exchangers use special physical processes to transfer heat from one side of the air to the other side of the air as it flows through the equipment, thus achieving the effect of reducing indoor temperature fluctuations.
2. Two-way flow system:
Two-way flow system is a new type of ventilation. It supplies air and exhausts air at the same time through air supply outlets and exhaust outlets arranged on the wall or ceiling. This system can effectively remove the dirty indoor air and introduce fresh outdoor air.

Second, working principle and characteristics

The working principle of the total heat exchanger:
The full heat exchanger carries out heat exchange through two separate air channels. When indoor and outdoor air flow through these two channels, heat will be transferred from the air on the high temperature side to the air on the low temperature side, so as to achieve heat recovery and utilization. This kind of system has the advantages of energy saving, reducing temperature fluctuation and improving comfort.
Working principle and characteristics of bidirectional flow system:
The bidirectional flow system mainly realizes ventilation through the simultaneous operation of air supply and exhaust outlets. This system can precisely control the amount of air supply and exhaust to keep the indoor air fresh and comfortable. In addition, the two-way flow system can also be controlled according to the needs of the zone, to meet the ventilation needs of different areas.

Three, the main difference
1. Functional differences: The full heat exchanger mainly focuses on the recovery and utilization of energy to reduce indoor temperature fluctuations; The two-way flow system pays more attention to the circulation and exchange of indoor and outdoor air.
2. Effect difference: the full heat exchanger can effectively recover heat, save energy, and reduce the cost of cooling or heating; The two-way flow system ensures fresh and comfortable indoor air.
3. Application scenario difference: Full heat exchangers are usually used in places with high requirements for energy saving and temperature control, such as homes, offices, etc. The two-way flow system is suitable for places where the ventilation volume needs to be precisely controlled, such as hospitals, laboratories, etc.

Iv. Summary
Total heat exchange system and two-way flow system have their own characteristics and advantages in the field of building ventilation. The total heat exchange system focuses on energy recovery and utilization to achieve energy saving and stable indoor temperature; The fresh air system two-way flow system pays more attention to the circulation and exchange of indoor and outdoor air, and improves the quality and comfort of indoor air. In practical applications, the appropriate system can be selected according to specific requirements and scenarios. At the same time, with the continuous development of science and technology, these two systems will continue to improve and innovate, bringing more possibilities and advantages to the field of building ventilation.