What methods are used to maintain high humidity in cold storage rooms for food storage?

The true cause of low humidity in cold rooms is the large temperature difference between the environment and the surface of the coils. The air unit is deposited on the surface of the coils which is colder than the ambient air. The lower the surface temperature, the lower the dew point of the air that is in contact with the coil. Humidity can be added to the air by means of steam jets, vaporizers, humidifiers, etc., but if the maintenance of low ambient temperatures requires coils with very cold surfaces, the introduced moisture will be deposited as frost in the Streamers. In order to achieve high humidity, the surface of the coils must be sufficiently large that the transfer of heat from ambient air to the refrigerant requires a minimum temperature difference.