|Hardin Iv, Robert
Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 8/21/2012
Publication Date: 8/21/2012
Citation: Hardin IV, R. G. ad Funk, P.A. 2012. Energy monitoring in gins - 2011. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). 2012 Annual International Meeting. Dallas, TX July 29 - August 1, 2012. Paper Number 12-1336884.
Interpretive Summary: According to a recent ginning cost survey, the average energy cost per bale was $5.18. This value represents the second largest source of variable costs for cotton gins, accounting for a quarter of variable costs. Energy use has not changed significantly in 50 years; consequently, a significant opportunity exists to improve gin profitability by reducing energy use. Studies of gin energy use have been conducted previously; however, this research only used data from utility bills or a single measurement during the ginning season. More comprehensive research is needed to understand causes of variation in electricity use at gins and identify specific opportunities in gins for energy conservation. Electricity and fuel use were monitored at two gins during the 2011 season. Motor loads were recorded for the large motors in gins: gin stands, fans, cleaning machinery, module feeders, and bale presses. Total power consumed by the gins was also monitored. Fuel consumption was estimated by measuring temperatures and air flow rates. The gins used 31.4 and 25.8 kWh.bale, less than the average electricity use, 41 kWh/bale, reported in a recent survey. The gins required 0.56 and 0.74 gal LPG/bale for drying and moisture restoration. Processing rate was the primary factor affecting electricity use per bale and also significantly affected fuel use. Seed cotton moisture and ambient temperature also affect fuel use. Different varieties of cotton ginned at significantly different rates; consequently, the energy used per bale was also different. Electricity used by different gin stand components indicated that further research needs to be conducted to improve gin stand controls to maximize processing rate while maintaining fiber quality. Less fuel per bale was used when ginning round modules than conventional modules, likely because the seed cotton was better protected from moisture. The bales on the ends of conventional modules required more fuel than the bales from the center, as wet areas in conventional modules are often found on the ends. Managers should operate gins at full capacity as frequently as possible and avoid idling equipment for long periods. To maximize processing rate and minimize fuel use, seed cotton must be properly stored so that cotton enters the gin at a suitable moisture content.
Technical Abstract: Energy costs are the second largest source of variable costs for cotton gins. Previous studies of gin energy use have only considered a single, instantaneous reading of energy use or examined monthly utility bills. More detailed information is needed to identify management strategies and system designs that can reduce energy use. Electricity use was measured and fuel use was estimated from air flow and temperature measurements at two gins during the 2011 ginning season. Electricity use averaged 31.4 and 25.8 kWh bale-1, with cultivar having a significant effect on processing rate and electricity use. The first stage dryer LPG use was 1.25 L bale-1 (0.33 gal bale-1 and 1.45 L bale-1 (0.38 gal bale-1). Only one gin operated the burner for the second stage drying system, requiring 0.32 L bale-1 (0.08 gal bale-1) LPG. Moisture restoration system LPG use was 0.89 L bale-1 (0.23 gal bale-1) and 0.38 L bale-1 (0.10 gal bale-1), although the lower value represented data collected mostly during the wetter portion of the ginning season. Round modules required less fuel per bale than conventional modules, as more fuel was used to dry the ends of conventional modules. Higher processing rates reduced electricity and fuel use per bale at both gins. For maximum energy efficiency, cotton ginners should operate at full capacity as much as possible and avoid idling equipment during significant downtime. Proper seed cotton storage, particularly with conventional modules, is also necessary to reduce fuel use.