ABSTRACT

An evaporative cooling system was developed in order to extend then shelf life of fresh fruits and vegetables. The system comprises of 0.075m3storage space, suction (4.3m/s), padding material slots, water reservoir (62.5 rn3 ), pipes and electric motor (0.5KW). Fiber glass (0.025rn) thick was used as a lagging material. Three different padding materials (rice husk, saw dust and plantain husk) of 0.06m each were used to test the cooling ability of the system. Also four fruits and vegetables (local pear, Avogadro pear, carrot and pawpaw) were also used to test the efficiency of the system. The results of the transient performance tests revealed that the evaporative cooling system chamber temperature and relative humidity depression from ambient air temperature varied over 16-26°c and 33-88% respectively. Ambient air temperatures and relative humidity during the test periods ranged over 26-33°c and 18-31% respectively. The shelf life of the vegetable produce inside the evaporative cooling system was extended by fourteen days although the proximate analysis revealed that the differences in proximate composition of fresh and stored fruits and vegetables are significant. Thus, the evaporative cooling system can he used for short term preservation of vegetables soon after harvest and it will be very useful in a developing economy like Nigeria. Potential improvements for evaporative cooling devices include improvements in materials used, mainly in absorbent pads