An experimental solar-powered adsorptive refrigerator tested in Burkina-Faso

An adsorptive solar refrigerator was built and tested in May 1999 in Ouagadougou, Burkina-Faso. The adsorption pair is activated carbon + methanol. The adsorber is also the solar collector (2 m², single glazed), the condenser is air-cooled (natural convection) and the evaporator contains 40 l of water that can freeze into ice. This amount of ice acts as a cold storage for the cold cabinet (available volume of 440 l). Elements such as valves and a graduated bottle are installed, but only for experimental purposes. Apart from these valves, and also ventilation dampers which are open at night time and closed at daytime, the machine does not contain any moving parts and does not consume any mechanical energy. Within the requirement of vacuum technology, the machine is relatively easy to manufacture, so that construction in Burkina-Faso is feasible. Experimental performance is presented in terms of gross solar COP. During the test period, irradiance were quite good (between 19 and 25 MJ m⁻²), but the ambient temperature was relatively warm (averagely 27.4 °C at sunrise and 37.4 °C at mid-afternoon). The experimental values of the gross solar COP lie between 0.09 and 0.13. Despite a warm climate, the performance of the machine compares favourably to previously published results.

Résumé

An adsorptive solar refrigerator was built and tested in May 1999 in Ouagadougou, Burkina-Faso. The adsorption pair is activated carbon + methanol. The adsorber is also the solar collector (2 m², single glazed), the condenser is air-cooled (natural convection) and the evaporator contains 40 l of water that can freeze into ice. This amount of ice acts as a cold storage for the cold cabinet (available volume of 440 l). Elements such as valves and a graduated bottle are installed, but only for experimental purposes. Apart from these valves, and also ventilation dampers which are open at night time and closed at daytime, the machine does not contain any moving parts and does not consume any mechanical energy. Within the requirement of vacuum technology, the machine is relatively easy to manufacture, so that construction in Burkina-Faso is feasible. Experimental performance is presented in terms of gross solar COP. During the test period, irradiance were quite good (between 19 and 25 MJ m⁻²), but the ambient temperature was relatively warm (averagely 27.4 °C at sunrise and 37.4 °C at mid-afternoon). The experimental values of the gross solar COP lie between 0.09 and 0.13. Despite a warm climate, the performance of the machine compares favourably to previously published results.