Design and Performance Evaluation of Small-Scale Off grid Solar Thermal Energy Milk Pasteurization System with CFD

Abstract

A milk pasteurization system was developed by utilizing solar thermal energy for off-grid periods of rural or urban milk products. This work sited on the warm climate condition of Doyogena. Doyogena is located in Kambata Zone, S.N.N.P.R ., Ethiopia. The milk pasteurization process consumes a huge amount of energy, using solar energy for the pasteurization process decreases the required conventional energy. While milk is a perishable food item and needs careful handling from source to supply. Unreliable handling of milk creates harmful pathogen and spoilage microorganisms and milk-borne diseases in developing countries especially in Ethiopia leads to millions of deaths and billions of illnesses annually. Milk producers in Doyogena, the study area not used any milk preservation systems. Therefore milk pasteurization system is one of several interventions that can improve public health. The purpose of this work is to analyze the performance of the solar energy-based system for the small-scale milk pasteurization process with a low-cost helical tube heat exchanger immersed in the milk storage tank. The effectiveness of the milk pasteurization system has been studied using CFD (computational fluid dynamics). The system uses 2.42 the gross area of an inclined evacuated tube solar collector and the solar radiation intensity on the inclined surface of the location has been analyzed from available solar data. The monthly average useful energy received by the collector ranges from 650Wh/ to 10720Wh/ and the maximum hot water temperature exit from the collector ranges from 79 to 82.32 using water as heat transfer fluid(HTF). Energy loss by convection heat transfer to ambient, the hot water temperature in the thermal storage tank (inlet to the helical tube heat exchanger) found to be 70 to 78 which above the required pasteurization temperature ranges from 65.5 to 69 . Overall results indicate that solar-based milk pasteurization system was viable technology in this manner and it achieved the acceptable milk temperature range being heated to kill microorganisms that leads to milk spoilage. I am recommended using an integrated storage system to optimize the system for large-scall milk pasteurization