ROUTING EFFECTS ON THE THERMAL PERFORMANCE OF REFRIGERATED VEHICLES IN THE DISTRIBUTION OF PERISHABLE PRODUCTS
The temperature of chilled and frozen products along the distribution process must be maintained within close limits to ensure optimum food safety levels and high quality. The variation of cargo temperature along the vehicle routing sequence is represented by non-linear functions which depend on the process stage (line haul, unloading at customer’s premises, local displacements, etc.). The temperature variability is also correlated with the time required for the refrigeration unit to recover after cargo unloading, due to door openings and the cargo discharging process. The vehicle routing optimization strategy employed in traditional cargo distribution applications is generally based on a TSP (Travelling Salesman Problem) sequence, with the objective of minimizing travelled distance or time. It is shown in the paper that in order to maintain the temperature variability within adequate restriction limits, other routing strategies, apart from the TSP criterion, should be considered.