Mechanical Ventilation: Common examples of mechanical ventilation are fans and exhausts, which are used to get rid of excess humidity http://www.raidersrookiestore.com/Raiders-Lester-Hayes-Jersey/ , oning (HVAC) units http://www.raidersrookiestore.com/Raiders-Lee-Smith-Jersey/ , heat is removed through the processes of radiation and convection. The cooling medium or refrigerants take the heat away from the surroundings by evaporation. Since they work at low temperatures, moisture in the air condenses onto the coils, which is collected and piped out to a drain, thereby controlling humidity. These systems have filters that need to be kept clean or replaced, to prevent power losses and improve efficiency of the machine.