Grain depth is an important factor in grain drying. Extra depth increases airflow resistance, decreasing the drying rate. This extra depth also increases fan power requirements and the cost per bushel of drying grain. Reducing the depth in a low temperature drying bin can speed drying, decrease the risk of grain spoilage and reduce drying cost. Typically, reducing the drying depth by one-fourth will reduce the energy cost per bushel by one-third.
When buying "deep" versus "shallow" or "low-profile" bins, it seems to make sense that the bin cost per bushel will be lower for a deeper bin. After paying for the concrete floor and roof, the cost of an extra ring or two results in cheap storage. However, this doesn't take into consideration the initial cost of a drying fan and motor or the cost of operating the drying fan.