The adsorption cooling machine under solar radiation is represented in figure 1. It consists of the following elements:

— A solar collector containing the adsorption reactor, it is heated under the action of solar radiation, and desorbs a gas amount which is a function of the maximum temperature.

— A condenser inside which the desorbed cooler condenses.

— A tank where the liquid cooler is stored.

— An evaporator, in contact with the cold source, in which takes place the evaporation of the liquid fluid at the pressure of evaporation Pev to produce cold.

— Automatic valves working under the basis of the pressure.

All these elements are connected by tubes, necessary to move the cooling fluid along a closed circuit made of, the adsorber, the condenser, the evaporator and the adsorber.

At the beginning, the porous medium temperature is uniform at ambient one and at evaporating pressure. The reactor is heated by solar radiation, which causes an increases in temperature and pressure. Thus an in-homogeneity in temperature derive a temperature gradient, while the pressure remains uniform in the reactive beds. Then a first phase is characterised by an elevation of pressure until the condensing value following an isoster. When the pressure reaches the condensing value corresponding to saturated pressure of ammonia at ambient temperature, the valve Vc linking the adsorber and a condenser is opened, permitting the circulation of ammonia vapour to the condenser through a tube. At this moment, the condensing phase start at constant pressure. The heating reactor and desorption of ammonia continues, until the temperature at the centre of the reactor reaches a maximum value. Then valve Vc closes automatically and the cooling of the reactor starts following an isoster. The valve Ve is closed and a new phase begins, characterized by a fall of the pressure to the evaporating pressure. Then the valve Ve is opened which permit to entering the fluid in the adsorber, induced as a result of the adsorption of ammonia on the activated carbon.