Seasonal Aeration Rates for the Eastern United States Based on Long-Term Weather Patterns

Most aeration fans are sized to produce a minimum airflow rate of 0.1 m3/min/t (0.1 cfm/bu) in on-farm grain storage structures. At this airflow rate a significant amount of time is required to move a cooling front completely through a bin. The desired grain temperature and prevailing weather conditions will have a significant effect on required fan size. Thirty years of weather data were analyzed for the eastern United States to determine the amount of time available in temperature windows between 0 to 15.C and 0 to 17.C. Contour maps were generated with ArcMap 8.3 for the percentage of each month within the given temperature windows. A substantial amount of time (over 4% of the month) is available within temperature limits of 0 and 17.C between September and April. This indicates that airflow rates of at least 0.6 m3/min/t (0.5 cfm/bu) would be more adequate to completely move an aeration front through a bin for summer harvested grain in Southern regions of the United States. However, during July and August only the northern half of the United States would have a sufficient amount of time available for cooling grain below 17.C using an airflow rate of 0.1 m3/min/t (0.1 cfm/bu). The maps generated provide a starting point for sizing aeration fans in the eastern United States

Aeration Strategies and Fan Cost Comparisons for Wheat in Mid-South Production Regions

Numerous factors influence the sizing of aeration fans for summer-harvested crops. Thirty years of weather data for Lexington, Kentucky, were analyzed and the cost of aeration was compared for two axial fans (afan1, afan2) and one centrifugal fan (cfan1). Aeration costs were defined as the sum of the following components: the cost of owning the fan, the cost of electricity for operating the fan, a cost for wheat shrinkage during aeration, and a cost for dry matter loss (DML). The fans were selected to deliver airflow rates of approximately one, two, and three times the recommended aeration rate of 0.11 m3/min/t (0.1 cfm/bu). Aeration fan investment costs ranged from $709 (afan1) to$1739 (cfan1). Aeration costs for each fan were compared for four initial grain temperatures: 21.1°C, 23.9°C, 26.7°C, and 29.4°C (70°F, 75°F, 80°F, and 85°F); four harvest dates: 1 June, 15 June, 1 July, and 15 July; and two aeration temperature windows (0 to 15°C and 0 to 17°C). Generally, the total aeration cost increased with initial grain temperature, decreased with later harvest dates, and was not significantly affected by aeration temperature window. When the total cost of aerating the wheat was considered, the results showed that the most expensive fan (cfan1) was not appreciably more costly than the least expensive (afan1). It was also found that using fans with airflow rates above the minimum recommendation were successful in reducing the amount of wheat shrinkage and dry matter loss, which should provide the producer with a larger volume of better quality grain at market

Facility Costs of Centralized Grain Storage Systems Utilizing Computer Design

The item considered most often when estimating the cost of a grain storage facility is capacity. Of equal or greater importance is daily harvest rate. Other important considerations include drying method, materials handling equipment, energy cost, facility arrangement, labor requirements, grain quality and management ability. Only through a comparison of facilities which offer similar capacity, capability and convenience can the purchaser obtain his best system

Equilibrium Moisture Properties of Corn Cobs

Equilibrium moisture content-equilibrium relative humidity data for broken corn cobs have been determined for both desorption and adsorption conditions for three temperature levels and five moisture levels. The Modified Henderson and Chung equilibrium moisture equations have been fitted to these data by using non-linear regression procedures to estimate equation parameters. Both equations adequately represented the experimental data. A test of varietal differences indicated no significant difference in cob desorption ERH values for three selected corn varieties

A Computer Model for Analysis of Alternative Burley Tobacco Harvesting Practice

Agricultural operations and practices have been the subject of many computer models and simulations. Holtman et al. (1970) developed a corn harvesting simulator, and Morey et al. (1971) used simulation techniques to analyze net profit of a corn harvesting and handling system during a particular weather year. Further, Loewer et al. (1977) advanced a model that assessed alternative beef production strategies for the individual farm with land, energy and capital as constraints. Bridges et al., (1979) developed a design simulation oriented toward the individual producer that examines corn harvesting systems and compares them regarding investment and annual cost. The CATCH (Computer Analysis of Tobacco Cutting and Housing) simulation model (Bridges et al., 1980) was written to apply similar principles to the analysis of burley tobacco systems

Assessing the Benefits of Misting–Cooling Systems for Growing/Finishing Swine as Affected by Environment and Pig Placement Date

The NCPIG swine growth model was used to evaluate swine growth performance for Wilmington, North Carolina; Bardstown and Mayfield, Kentucky; and Oklahoma City, Oklahoma as influenced by the use of a misting–cooling system. Five pig placement dates (Julian days 106, 126, 146, 166, and 186) were evaluated for each location using 22 years of weather data (1978–1999). The use of a misting system, while quite variable, was found to be generally profitable, reducing the length of the time to reach market weight. As the placement date increased, the average return to misting ($/pig/year) decreased from$8.12 to $1.98 for Oklahoma City, from$6.00 to $1.16 for Wilmington, from$4.14 to $0.99 for Mayfield, and from$3.07 to $0.87 for Bardstown. Based on the prorated value of$1.39 per pig/per year for the cost of a misting system, probabilities for recovering the initial investment amount were determined for each pig placement date and location. These probabilities decreased as the pig placement date increased, except for Oklahoma City, which remained above 98% regardless of the date. For the locations other than Oklahoma City, the probabilities indicated that the earlier placement dates were more favorable for recovering the initial investment

Assessing the Benefits of Misting-Cooling Systems for Growing-Finishing Swine in Kentucky as Affected by Environment and Pig Placement Date

The growth performance of animals is often affected by extreme environmental conditions. In the case of swine, generally a cold environment will increase feed intake as the pig strives to maintain body temperature, while warmer environments may reduce growth, increase body maintenance demands, and subject the animal to environmental stress. Confinement houses are widely used as a primary means of modifying the environment to improve conditions for the growth of swine. Environment in these structures is usually controlled by natural or mechanical ventilation and by insulation for cold climates and limited use of evaporative cooling for summertime conditions