Design of mobile raw milk chilling unit for rural areas

Transportation of raw milk from village to the dairy requires lot of care, as there is no chilling unit at the village collecting centre. Freshly collected raw milk at village co-operative societies is transported to chilling unit and the route is specified by the milk federation. In such a chilling unit, milk collected from many such routes is chilled and then transported to secondary processing unit once in a day. To maintain quality, the milk has to be chilled at village co-operative society level. Since, the quantity of milk collected is less (40–200 litre), chilling does not take place at this level. Bulk milk chillers are not suitable for this purpose. Currently, raw milk transport method is also not hygienic and loading-unloading methods are very crude without ergonomic consideration. A better solution for this problem is to transport raw milk stored in a refrigeration system, which has a proper layout, storage facility for milk cans, and handling equipment which will reduce the effort and time required to load and unload the milk cans.

Literature review on transport refrigeration of various food products was carried out by referring to books, journals, websites and refrigeration unit catalogues. Information regarding the present method of milk collection, primary chilling, transportation method of raw milk and documentation process was obtained from the Dairy Co-operative Societies. Information was also gathered by surveying the collection centres. Requirements to preserve the quality of the milk as well as information on duration of collection and transportation were collected. Data regarding the current trends of transport refrigeration were also collected. Heat loads were calculated as per the requirements. Based on the collected data, Product Design Specification (PDS) and Quality Function Deployment (QFD) were generated. Various concepts of the vehicle were sketched and a 2D layout was designed using AUTOCAD software. A final concept was selected and 3D model was created using ALIAS and CATIA geometric modeling software. A mock up model was built based on the final concept.

Heat loads obtained from calculations for route “G” and route “B” were 11125W and 9974W respectively. Weight calculations, cost estimation for the project and chilling cost were carried out. After chilling, the total price per liter of milk was approximately INR 28.70. This is a feasible alternative for good quality raw milk transportation. Chilling plant can be completely eliminated as mobile chillers are used for transportation of the raw milk.