If a walk-in cooler needs to maintain a high moisture level in the air, what should the logical evaporator temperature difference (TD) be?

To maintain a high moisture level in the air within a walk-in cooler, the evaporator temperature difference (TD) should ideally be around 20 degrees. This TD is crucial because it balances the need for cooling with humidity control. A lower evaporator TD allows for better heat exchange, which means the evaporator coil can effectively remove heat while retaining moisture in the air. This helps in creating a humid environment, which is often required for certain food storage applications, such as fresh produce, that benefit from higher moisture levels to preserve quality and shelf life.

If the evaporator TD were too low, it might result in insufficient cooling, while a TD that is too high would lead to excessive dehumidification, causing the environment to become too dry. Therefore, 20 degrees is seen as a practical and efficient balance for maintaining the necessary humidity while ensuring adequate cooling in a walk-in cooler setup.