Anyanwu (2004) carried out the design, construction and measured performance of a porous evaporative cooler for the preservation of fruits and vegetables. The experimental cooler had a total storage space of 0.014 m3. The cooler consisted of a cuboid shaped porous clay container located inside another clay container. The gap between them was filled with coconut fibre (Datta et al. 1987). A flexible pipe supplied water to fill the gap, thus keeping the coconut fibre continuously wet. Results of the transient performance tests revealed that the cooler storage chamber temperature depression from ambient air temperature varied over 0.1 to 12 °C. Ambient air temperatures during the test periods ranged over 22 to 38 °C. The results also illustrate superior performance of the cooler over open air preservation of vegetables soon after harvest during the diurnal operations. Thus, the evaporative cooler has prospects for use for short term preservation of vegetables and fruits soon after harvest.
Thiagu et al. (2007) compared the tomatoes ripened in evaporative cooling (EC) storage conditions (20°C–25°C, 92–95% RH) with control fruits stored under room conditions (28°C to 33°C, 45–65% RH) during summer in Mysore. Evaporative cooling ripened tomatoes on the 15th day reached 100% ripening index (RI) with a value of 2.48 for the ratio of redness to yellowishness (a/b) and hue angle (?) of 22.1° whereas the control tomatoes on the same day reached a maximum 83.3% RI with a/b ratio of 1.59 and a hue angle of 32.9°. The lycopene content of EC ripened fruits doubled that of the control. EC stored fruits showed lower values for rupture and shear stresses. The rate of moisture loss for control fruits was 6.5 times as great as for EC stored tomatoes.
Dadhich et al. (2008) constructed an evaporative cool chamber with the help of baked bricks and riverbed sand. Maximum and Minimum temperature and relative humidity were recorded inside and outside the chamber for a month. The inside temperature was found to be 10 to 15 °C lower than the outside temperature and inside humidity was about 30 to 40% higher than outside. It has been recorded that weight loss of fruits and vegetables kept inside the chamber was lower than those stored outside the chamber. The storage of fruits and vegetables as fresh was up to 3 to 5 days more inside than outside of the chamber.