Cooling milk using sun energy

The company Tarre of Navarre in collaboration with the Public University of Navarre has built a prototype for cooling milk. This cooling and maintenance system takes the energy directly from a photovoltaic system and so there is no need to use batteries.

The prototype integrates two concentric cylindrical tanks in a single structure: the first one is a cooling chamber for the milk and the second one is a tank of frozen water. In this system the first tank is inside the tank of frozen water. That way milk is cooled without using any pumping system.
Due to the difference between the moment when the energy requirement is greater, that is, right after milking, and the photovoltaic generation process, that is, when sun irradiation is sufficient, there must be a solar energy storing system. Thus Maria Angeles de Blas, from the Public University of Navarre has proposed the use of energy produced during the state conversion from ice to water, as an alternative of the usual electrochemical batteries. Moreover, those batteries have a lot of problems, such as, high economic costs, need of maintenance and they contain highly contaminant elements.
The system has added a new concept to the cooling systems: the assembly of the photovoltaic system directly to the milk tank without using any kind of intermediary power conditioning system or any microprocessor. This way the technology used is simplified and energy requirement is reduced. It must be taken into account that milk needs to be cooled to 4 º C in a specific period of time and then it must be maintained in that temperature until it is taken away from the cooling chamber.
The storing range of the system is 2 days and a half when in the tank ice is at 80 % of its capacity. According to Maria Angeles Blas the results of the cooling efficiency of the system is similar to those reached by the usual systems, which use electrochemical batteries to store energy.
,Two cooling circuits
After studying several alternatives, they decided to have two cooling systems, similar but independent. So depending on the power consumption and on the photovoltaic energy stored, one or two systems will be working. So when the sun irradiation is high, the system will store energy, and that energy will be used for the second milking at night.
In order to adequate the working level, derived from the direct assembling between the solar generator and the cooling subsystem, to conditions of irradiation and temperature existing in each moment, the configuration of the photovoltaic field and the number of cooling circuits that are operating is changed. This way due to the available energy only one of the cooling circuits or both will be working.For further information please contact, ,I?aki Casado Redin,Public University of Navarre,e-mail: [e-mail]

Pays

Spain