The smog weather around the Spring Festival has suddenly brought the market of air purifiers. When consumers are shopping, the salesperson will enthusiastically introduce you to the magic purification effect of this air purifier. In the process, consumers may Will come into contact with a new word - clean air volume or CADR value, then what is the amount of clean air, what does the CADR value mean?

What is the CADR value? The English abbreviation of the CADR value clean air delivery rate, the Chinese abbreviation for clean air volume, refers to the clean air output ratio, is an internationally recognized purification performance indicator of the air purifier.

CADR is the ratio of clean air output by air purifiers obtained by the American Association of Home Appliance Manufacturers (AHAM) in accordance with rigorous testing standards. The higher the CADR value, the higher the purification efficiency of the purifier. CADR is a performance indicator that reflects its purification capacity, in m3/h.

The calculation method of clean air volume CADR is:

CADR=60×(ke-kn)×V

Where: CADR - clean air volume, m3 / h;

V——lab volume, m3;

Ke - total attenuation constant, min-1;

Kn - natural decay constant, min-1.

The attenuation constant can be calculated from the test value of the concentration change of the pollutants in the air before and after the operation of the purifier in the laboratory, and is calculated by the following formula:

Ct /Co=e-kt

Where: Ct——the concentration of pollutants after the t-time of the purifier, mg/m3;

C0——the concentration of pollutants in the background before the purifier works, mg/m3;

K——attenuation constant, min-1; (ignoring the natural decay constant)

t——The time when the purifier works, min.

Ignoring the natural decay constant, the above two equations can be combined into:

CADR=-ln(Ct- C0)V/t

According to the quality requirements of international air purifiers, in the applicable space, when the concentration of pollutants exceeds the standard limit of 5 to 10 times, the air purifier is turned on for 60 minutes, and the pollutants in the indoor air are required to be removed by 90%. Thus, in the above formula, the value of ln(Ct-C0) is -ln10, which is approximately equal to -2.3.

The above formula is simplified as:

CADR=2.3V/t

China Antibacterial FABRIC Network Latest Antibacterial Fabric Information