Modelling of Thermal Environment in Covered and Plinth Storage of Wheat as Effect of Colour of Plastic Sheet

Abstract

Traditional temporary storage methods used for crops are Cover-and-plinth (CAP), flexible silos, pit storage and bunker storage. The CAP is commonly adopted in India for storage of bumper crops. In India, about 16.8 Mt of wheat grains are stored in CAP storage due to insufficient indoor storage facilities. Black coloured plastic covers (250 micron) are used for CAP storage structures, which are exposed to open sun, get heated up due to characteristics of black colour resulting in build up of higher temperature of air surrounding the grain and higher grain temperatures. A solar energy based thermal model was developed for predicting wheat grain temperature while stored in CAP. The model was solved for the climatic conditions representing northern India (Haryana, Punjab and Uttar Pradesh). Around 10 to 12°C rise in yearly grain temperature from mean monthly ambient temperature could be observed with black cover. The model was validated with the two months of experimental data of CAP storage with black cover, which showed fair agreement with the experimental values. A white colour plastic cover was proposed with simulated results indicating to reduce the grain temperature by 6 to 8 °C.