Characteristic principle of hvac is household central air conditioning, central air conditioning its biggest characteristic, is the ability to create a comfortable indoor environment. And household generally fission air conditioning, it can only solve the problem of changes in temperature, and cannot solve the air handling process. The hvac are different. Its air handling process has the following steps: first is the air, in addition to the introduction of new wind, can handle air for cooling, then filtering processing, filtering processing, increased a few big characteristics: first increase electrical dust collector. , it can capture very small particles of dust, in general it can capture a micron dust, the dust within the scope of smoke, most of them are bacteria, viruses, or is peculiar smell so that it can filter out; Another is increased a humidifying equipment, the humidification humidifier can create our room around 40% relative humidity, so that people will feel very comfortable.