SOLAR ENERGY COOLS MILK

Hot weather days cause often large fresh milk defect in southern developing countries dairy farms as well as in rural areas where there is a scarcity of energy sources that could run cooling equipments. Consequently, the possibility to use solar cooling starts to be considered an attractive solution. The aim of the work presented is to develop an innovative solar thermally driven cooling concept, to be used for received fresh milk in a dairy factory in the city of Marrakech, Morocco. The work has been carried out in the framework of the EC co- funded project (i.e., MEDISCO). The system is intended for refrigeration at 5°C in hot climates, and is composed of: medium temperature collector, single effect water ammonia absorption chiller, cold storage. The peculiarity of the configuration is the high temperature difference between the chilled refrigerant temperature, about -5 °C (in consequence of using an ice storage) and the condenser temperature (ambient temperature, which could exceed 35 °C). In these conditions, the absorption chiller must be driven by a medium temperature heat source (i.e. parabolic trough collector). Moreover, the selected chiller is directly air cooled, and has the main advantage of having no water consumption, low maintenance work and no legionella problems. . TRNSYS simulations were performed to select the appropriate system configuration, size of the solar collectors' field and the storage, heat transfer fluid and control strategy. A summary of the results is given. The choice of a proper solar assisted refrigeration system for hot climates , has to take into account the boundary conditions of the site and the application - i.e., level of temperature. The aim of the work presented it has been to develop an innovative solar thermally driven cooling concept, to be used for received fresh milk in a dairy factory in the city of Marrakech, Morocco. The work, carried out in the framework of the EC co-funded project MEDISCO (MEDiterranean food and agro Industry applications of Solar COoling technologies), investigated through simulations the optimum system configuration, size of the solar collectors field and the storage, heat transfer fluid and control strategy. Further a description of the system concept, industrial application load profile, model employed and simulation results is given.