• By air;
• Electric;
• By water;
• By hot gas;
• Mixed (hot gas + water).
Whatever the process of defrosting and water is channeled to the outside of the chamber through drain pipes. These should be siphoned to prevent the ingress of outside air. In the negative temperature chambers the drains are heated in the section that is inside the chamber, the heating of the drains is usually done by electrical resistance even if another method of defrost is used in the evaporator.
