Drying Considerations for the 1996 Corn Crop

The com harvest season has already started on some farms and is rapidly approaching for many others. Current market opportunities and previous contractual arrangements have some farmers thinking about starting their harvest earlier than usual. Other factors also suggest that a substantial portion of this year\u27s crop could be harvested at moisture contents between 24 and 32%

Operational Considerations for Harvesting Corn Above 25% Moisture Content

Many of Kentucky\u27s grain farmers are interested in harvesting corn at higher moistures than in recent years because of potential market trends and weather patterns. Corn that was planted early is near maturity in many western KY counties and fortunately, the market is higher than in previous years. Additionally, most elevators are offering premiums between 25 and 50 cents per bushel for corn delivered prior to Sept. 15 this year, so farmers who have drying equipment are poised to take advantage of this rare opportunity. In contrast, late planted corn may be threatened by an early frost, so actually both groups of farmers are seeking information regarding the precautions and opportunities for harvesting corn at moisture levels higher than they may have experienced in recent years when weather has been favorable for field drying

Electronic Controls for Swine Buildings

This fact sheet discusses the use of electronic controllers to maintain the environment within swine barns. There are some special considerations when using electronic controllers to replace traditional control systems. Three main items are addressed in this fact sheet: 1) the selection of a controller, 2) installation considerations, and 3) protection against controller failure

Transient Overvoltage Testing of Environmental Controllers

The integrated electronic control system will provide a new method for the day-to-day management of environmental control of animal production systems. No standards are currently accepted for transient overvoltage protection of these controllers. To assess the adequacy of existing designs, a test circuit was designed and used for a transient open circuit over-voltage waveform (ANSI/IEEE C62.41-1980) of 16 environmental control units: a maximum spike of 770 V was applied to the power supplies, and a spike up to 100 V was applied to temperature sensor lines. For these relatively mild tests, no failures were noted due to power supply transients, but three units failed when subjected to transients on their temperature sensor lines. From this research it is suggested that an industry standard be adopted to define the minimum transient overvoltage design conditions by which environmental controllers should be tested

Mechanical Backup Systems for Electronic Environmental Controllers

A series of mechanical backup systems for electronic environmental controllers is presented for a typical finishing swine barn and a typical tunnel ventilated broiler house. The systems consist of mechanical thermostats and timers used in parallel with the electronic controller, designed to ensure animal survival in the event of controller or related hardware failure. For swine housing, three distinct mechanical backup functions are identified; for broiler housing, four distinct mechanical backup functions are identified. Schematic diagrams of the mechanical backup functions are provided and their implementation is described

A Survey of Electronic Environmental Controllers

Sixteen commercially available electronic environmental controllers were evaluated. The units were classified according to enclosure type, analog versus microprocessor based control, power supply, sensors, alarms, control relays and triac output, interval timers, outside temperature feedback, and retail price. An assessment of these controllers indicated several critical limitations in the application of this technology. The use of integrated controllers for animal production has the potential for substantial improvements in production efficiencies. If the limitations observed in the present controller technology, as represented by this sample, are addressed, industry acceptance of the technology can be accelerated. A uniform standard to address this technology is recommended and specific suggestions are provided for what the standard should address

Minimum Ventilation for Modern Broiler Facilities

New functions for whole-house broiler heat production as a function of bird age using modern straight run broiler growth rates are presented and compared to values in the literature. The approximations are based on field measurements of environmental conditions in modern broiler housing, using a technique that matches predicted to actual fuel use to estimate partitioning between latent and sensible heat. Development of a program utilizing these approximations to compute ventilation and heating requirements for temperature and humidity control in broiler housing is described. The program utilizes steady-state heat and moisture balances commonly used for design purposes, with hourly or daily time steps. Data input includes bird weight and numbers, house data including overall R-value and size, inside and outside temperature, and relative humidity. The program estimates ventilation for temperature and moisture control, minimum ventilation rate, and supplemental heat required. Example predictions are provided

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

An Aeration Duct Design Model for Flat Grain Storage

Traditionally most grain is stored in circular type bins which provide a convenient means for handling and management. With the excess grain production and government loan programs of the past few years, some producers have used rectangular structures and covered piles to complement their round storages. The recommended management practices used with round bins are still required in those alternative storages and may be more critical in obtaining a quality end product. One such recommended practice used with round bins is aeration. This practice is used to maintain a uniform temperature in the grain mass, preventing condensation and hot spots from occurring in the bins. For grain stored in piles and rectangular structures, aeration is generally conducted using above floor or flush mounted duct systems. The design of these systems is dependent on several factors including the configuration of the grain mass, the design airflow rate and grain volume and duct spacing criteria that will provide a relatively uniform distribution of air throughout the grain mass. The objective of this paper is to present a computer model that will determine duct sizes and duct spacing for aeration of rectangular storages based on system design requirements specified by the user. The model will be developed for use on the personal computer and should provide a useful design tool for extension engineers