Another device known as "constant temperature and humidity air conditioning unit", also known as "constant temperature and humidity air conditioning", "precision air conditioning", but more known as "constant temperature and humidity". Constant humidity machine", this type of product has just appeared in the country, has not yet developed a targeted relevant national standards, in the actual operation process, generally with reference to the air conditioning and HVAC design standards, in addition to the two sides agreed on the technical parameters, but also because of this, to a lot of non-professional companies have the opportunity to take advantage of.