Unveiling the Pain Point of the Industry: The Phenomenon of Centralized Return Air in Ventilation Systems

Straight to the Point: Pros and Cons of Centralized Return Air

Our Viewpoint: The disadvantages outweigh the benefits, primarily due to overflow issues

Today, I bring to you an old problem: "Centralized return air or room-by-room return air?" . I want to talk about the technical defects and industry regression caused by cost.

Customers of ventilation systems are easily hurt because centralized return air fulfills all the imagination of non-professional customers:

1. Exceeding regular design and choosing a large air volume host: It caters to the imagination of ventilation volume. However, while the host is large, the distribution box is small, and the diameter reduction is too early, resulting in a substantial loss of air volume between devices. The fresh air often cannot reach the core comfort zone.

2. Having an overflow air diagram: This satisfies customers' imagination of exhaust air flow organization. However, without return air guidance, the wind is expected to travel around the core comfort zone and return. This is like assuming that the wind has emotions and can understand the owner's heart.

3. Having a centralized return air box: This meets the imagination of exhaust effect and noise. However, the main return air pipe comes directly into the living room from the fan. How can high-frequency noise be eliminated, and how can low-frequency noise be dealt with? Is it okay for the living room to bear the noise?

Causes of Centralized Return Air Phenomenon

The phenomenon of centralized return air is caused by the following reasons:

1. Consideration of installation materials and labor costs: Everyone knows that the cost of ventilation systems is linearly proportional to the volume. If the volume remains unchanged and the pipeline is halved, the auxiliary materials and labor will be significantly reduced.

2. Safety issues: ventilation punching is very sensitive. The property management of houses has high demands. Basically, you ask the property management, and the reply is not to punch. Total centralized return air can reduce 80% punching, and the delivery air pipe reduces another 20% pipeline, thus reducing 50% pipeline overall, including the behind-the-scenes labor and punching.

Drawbacks of Centralized Return Air

Large flats, row houses, and detached houses are becoming more popular, especially main bedrooms, which can easily exceed 30 square meters. How to handle it without a return air pipe? Overflow through the door gap? Have you calculated the resistance?

So, What Do We Recommend?

Whether it's ordinary ventilation or dehumidifying ventilation, the pipeline design and installation concept should be the same: ——Recommended air flow organization of the zonal supply and exhaust structure

Our approach is as follows:

1. Design the host according to demand, 100% (or above) restore the design air volume, considering the external static pressure of the equipment and pipeline resistance;

2. Correctly budget for the "most unfavorable loop resistance" to ensure the freshest air volume at the farthest end;

3. Design ventilation volume considering each pipe's capacity, noise, and resistance: It's crucial to ensure that each pipeline can handle the designed air volume without causing unnecessary noise or resistance that could hinder the system's efficiency.

4. Combine individual return air and centralized return air, fully considering the overflow problem: By combining these two methods, we can better control the airflow and prevent issues like overflow, which can lead to inefficiencies or discomfort in the living spaces.

5. Set up positive and negative pressure air outlets to guide the airflow direction and prevent dead corners of ventilation flow: By carefully setting up the air outlets, we can guide the air to flow in a way that maximizes comfort and efficiency and eliminates areas where air might become stagnant.

6. Partially centralize the return air to guide the fresh air used in the core comfort zone to polluted areas like bathrooms for secondary use: This approach not only ensures that fresh air reaches the most important areas but also makes efficient use of this air by redirecting it to areas where it can help improve air quality.

If you need more information or have any questions, feel free to reach out by email: sales@dpurat.com