Most cooling systems require openings to both exhaust heated air and to allow fresh air to enter the enclosure, but there are situations in which aesthetic considerations rule out two openings. Built-in cabinets can also be a problem for the custom installer; frequently the only surface available for ventilation is the front, where openings are most visible.
Using only one small opening at the very bottom of a cabinet, trimmed with either a wood or anodized aluminum grille (wall-hung cabinets and cabinets on legs need no grille), the new "6-pack" fan module developed by ATM is powerful enough to quietly force heated air out through the gap (typically 1/8") between the cabinet's doors. (See the airflow diagram below.) Where doors close completely, small shims supplied with each system can be used to create narrow gaps. Like all ATM products, the System 4 is completely automatic; fan operation and speed is controlled by the temperature within the enclosure.
While it should not be the "first choice", the System 4 is appropriate to use when aesthetic considerations rule out other ventilation methods.