Research on the space temperature control of grain bins with groundwater and heat exchanger

Abstract

As the grain temperature in a grain depot increases in spring and summer, deterioration of stored grain by mildew and pests can become serious. To solve these problems, a temperature control technique for the storage bin using a heat exchanger, fan coil units (FCU) and the abundant groundwater resources in Hangjiahu Lake in southern China was studied. The results indicated that the head-space temperature (HST) of the treated bin was controlled effectively; the maximum HST was less than 26°C. The maximum grain temperature of the surface layer (GT-SL) of the grain mass was less than 25°C in the treated bin, the increasing rate of GT-SL was stabilized. The average grain temperature (AGT) in the whole grain mass was less than 18.3°C. In the control bin, maximum HST was about 36°C, maximum GT-SL reached 28.7°C peak temperature, meanwhile, the rate of temperature increase in grain layers was rapid, with the AGT of 21.0°C. Using heat exchanger technology for 11 wks, the electricity cost was 1.175 RMB/t of grain. Therefore, a quasi low temperature grain storage (QLTGS) has been achieved in the experimental bin with this new method in Zhengjiang Province, China. It will have an important significance for safe grain storage. Keywords : Grain storage; Low-temperature Grain storage; Groundwater; Heat exchanger; Fan coil unit