Abstract:

The solar energy is a renewable resource, clean and environmentally friendly. Instead of using electricity, oil or gas energy to drive the adsorption of refrigeration machines, solar thermal energy (solid adsorption, activated charcoal/methanol) is an attractive alternative, mainly in places in which the electrical power is not available. A group of four students were given the project of developing a workable refrigeration machine with the use of solar energy. The activated charcoal was put inside a solar heating tube consisting of two concentric tubes, the external is vacuum evacuated, and the inner tube filled with activated charcoal and covered with a layer of black copper oxide to absorb the solar radiation. The cycle of adsorption refrigeration consists of two steps the daytime process in which the methanol is separated from the activated charcoal, and the nighttime process in which the methanol is absorbed again by the activated charcoal. Using this cyclical process it is possible to obtain a temperature of 4ºC.

The students were able to construct and test the solar refrigerators successfully , this projects are done at the Universidad Nacional Autónoma de Mexico to develop learning skills and motivate students to the technical careers.

Keywords:

Solar refrigeration, adsorption, equilibrium, cooling, developing working projects.