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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #338232
Research Project: Defining, Measuring, and Mitigating Attributes that Adversely Impact the Quality and Marketability of Foods

Location: Healthy Processed Foods Research

Title: Development of wind operated passive evaporative cooling structures for storage of tomatoes

Author
item SUNMONU, MUSLIU - University Of Ilorin
item CHUKWU, OGBONNAYA - The Federal University Of Technology
item Haff, Ronald - Ron

Submitted to: Arid Zone Journal of Engineering, Technology and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2016
Publication Date: 8/1/2016
Citation: Sunmonu, M., Chukwu, O., Haff, R.P. 2016. Development of wind operated passive evaporative cooling structures for storage of tomatoes. Arid Zone Journal of Engineering, Technology and Environment. 12:94-102.

Interpretive Summary: In order to find an alternative cooling mechanism for freshly harvested crops in rural settings where electrical power is not available, a wind powered passive evaporative cooler was developed. Two cooling chambers (one cylindrical and one square) made from clay containers were (separately) inserted into larger clay pots interspaced with 7 cm of soil to form “pot-in-pot” and “wall-in wall” cooler designs. Each outside structure was wrapped with a jute sack, and the soil and the jute sacks were soaked with a salt solution. An exterior wind powered vane consisting of five aluminum blades rotated a shaft which extended into the cooling chamber to drive a fan blade. The total volume and storage capacity were 40,500cm3 and 31,500cm3 respectively for the square design and 31,793 cm3 and 24,728 cm3 for the cylindrical design. During the test period (month of October), average temperatures of 27.07 oC and 27.09 oC were maintained for the square and cylindrical designs respectively vs. an ambient average temperature of 33.6 oC, demonstrating the efficacy of either design for cooling. Furthermore, average relative humidity of 92.27% (square design) and 91.99% (cylindrical design) were measured vs. 69.41% for ambient air. Wind speed at the test location was consistently between 2.5m/s and 2.6m/s for the month.

Technical Abstract: A wind operated passive evaporative cooler was developed. Two cooling chambers were made with clay containers (cylindrical and square shapes). These two containers were separately inserted inside bigger clay pot inter- spaced with clay soil of 7 cm (to form pot-in-pot and wall-in wall) with the outside structure wrapped with a jute sack. The soil and the jute sacks were wetted with salt solution. Five blades were constructed inside the cooling chambers with aluminum material which were connected with a shaft to a vane located on a wooden cover outside the cooling chamber. The vanes (made of aluminum) were to be powered by the wind which in turn rotates the blades inside the cooling chamber. The total volume of 40500cm3 and storage capacity of 31500cm3 were recorded for the square structures while total volume of 31792.5cm3 and storage capacity of 24727.5cm3 were recorded for the cylindrical structures. During the test period, the average temperatures of 27.07oC, 27.09oC and 33.6oC were obtained for the pot-in-pot (cylindrical), wall-in-wall (square) and the ambient respectively. The average relative humidity of 92.27%, 91.99% and 69.41% were obtained for the pot-in-pot (cylindrical), wall-in-wall (square) and the ambient respectively. The average minimum and maximum wind speed recorded for the month of October was 2.5m/s and 2.6m/s respectively.