ABSTRACT
As a result of the need to minimize the huge losses of perishable agricultural crops produced in the rural communities and preserve their fresh qualities before getting to the consumer, at the farm and market levels, a storage system for fresh tomato was designed and constructed with the locally available raw materials. The storage system works on the principles of evaporative cooling involving the process of heat transfer from the storage chamber to the wet Hessian sack which encloses the cooling medium. A preliminary experiment was carried out during the harmattan period and a second experiment off-harmattan period. The result obtained during the off-harmattan period reveals that the equipment can store fresh tomatoes for 30 days at average temperature and relative humidity of 22.9�C and 98.2% respectively when the average ambient temperature and relative humidity respectively were 30.9�C 8nd 37.3%. Also, the result obtained during the harmattan period shows that the equipment could store fresh tomatoes for 23 days at average temperature and relative humidity of 17.1�C and 82.1% respectively when the average ambient temperature and relative humidity respectively were 25.15�C and 28.29%. Compressive strength of the stored produce varies between (o.550 N/mm2 - 0.122 N/mm2) and (0.550 N/mm2 - 0.081 N/mm2) respectively with the storage equipment and the control system from the initial to the final day of storage during the harmattan period. And also varies viii between (0.546 N/mm2 - 0.112 N/mm2) and (0.546.6 N/mm2 - 0.073 N/mm2) respectively with the storage equipment and the control system from the initial to the final day of storage during off-harmattan period. The initial state of the tomato before testing was green and the state at the end of the test during the the harmattan and Off-harmattan period was deepred with rot appearance. The duration of test were 30 days and 23 days respectively for off-harmattan and harmattan period, A factorial experiment was considered for estimating the effect of size, thickness of the Hessian sack and interraction of the variables under room condition. The result obtained during the experiments (off-harmattand and harmattan) reveals that the calculated effect of size of the storage system was statistically significant while the calculated effect of thickness of the Hessian sack and interraction between size and thickness of the Hessian sack was not significant at 0,05 confidence level. Cooling efficiencies of over 93% and 98% respectively was achieved with the storage system during the harmattan and off-harmattan period while the humidification efficiencies attained was 93% and 95% respectivley during the harmattan and off-harmattan seasons.