COTTON GINNING HANDBOOK: Energy Utilization and Conservation in Cotton Gins

Gins have become more energy efficient. However, energy costs account for 25% of the total variable costs of ginning, including seasonal labor, increasing from 15% in 1994. Recent studies found that average electricity use at gins is approximately 35 kWh per bale, down from 53 kWh per bale reported in 1980. However, gins must continue to increase efficiency to remain profitable and consumers are increasingly concerned with the sustainability of textile products. This paper reviews recent research on energy use and conservation in cotton gins and offers suggestions on ways for gin managers to reduce energy use based on this research. Gins should focus on maximizing their ginning rate and sustaining this rate as much as possible during the ginning season. Increased ginning rates will reduce per-bale costs of not only electricity and fuel, but labor as well. Maintaining consistent material flow through the gin, matching equipment capacities, and minimizing downtime allows gins to produce more bales per shift. More than half the electricity at gins is used for material handling, primarily by the large centrifugal fans used to convey materials. The cost of conveying materials should be considered when designing or updating gins. Gins should use only the volume of air necessary for consistent conveying and adequate drying and need to eliminate unnecessary friction losses in conveying systems. To reduce fuel use, dryer control systems should be used to avoid excessive drying of cotton. Insulating drying systems might be economically feasible, particularly from the burner to the mixpoint. Gins also should consider strategies to reduce the prices paid for electricity and fuel.