Comparison Of Fresh And Frozen Products Transport
The main difference between fresh and frozen product is that fresh food (fruit, vegetables, not fully ripened cheeses) often has a metabolic charge (fee increases with temperature)and frozen products do not have an extra charge. Hence, fresh goods must be ventilated so as to provide ventilation to each piece of cargo so that the temperature does not rise in any position. On the contrary, frozen cargo should be as compact as possible and air circulation is required only for the outer surface of the CD cargo. The thermal inertia of frozen cargo is large and therefore the ventilated air in the vehicle to remove the heat transferred to isolation from outside the vehicle.
Test standards require temperature vehicles does not exceed -20C. If the vehicle has been to maintain the same conditions that many cold storage, transport temperature -25C to -30C. This situation means that the value of K should be lower than envisaged by standards, and loss of productivity in the refrigeration aggregate at low temperature, should be considered (Fig. 13.11 shows a typical curve of the power and efficiency of the unit)...