When you cool a crate of milk pouches from 30 °C to 4 °C, you remove sensible heat. The temperature changes but the milk stays liquid. The amount depends on the mass and the specific heat of the product: water-rich foods such as milk, curd, vegetables and meat need roughly 3.5 to 4 kJ per kilogram for each degree of cooling.
In a cabinet, the sensible load includes warm product, the warmth of air that rushes in when the door is opened, heat conducted through the walls, and heat from fans and lights. It shows directly as a rise in cabinet temperature, and a thermometer or controller probe responds to it.
Sensible heat is the reason loading practice matters. Putting 20 kilograms of freshly cooked, still-warm gravy into a reach-in adds a large sensible load in one go, which raises the temperature of everything around it. Cooling hot food first, in shallow containers or a blast chiller, keeps the storage cabinet doing the job it was designed for.