Horizontal Ventilation Storage Facilities. Sweet potatoes are North Carolina's number one horticultural crop. Sweet potatoes are harvested in late summer and fall and stored for shipment throughout the year. Many of the large storage facilities have capacities of more than 400,000 bushels. To keep the sweet potatoes in good condition in these facilities requires sophisticated ventilation, temperature and humidity control. Computer controlled horizontal ventilation, a method new to sweet potato storage developed at NCSU, is being used successfully on approximately 4 million bushels of the 1995 crop.
Thermal Storage Immersion Hydrocooler. An experimental immersion hydrocooler has been designed, built and extensively field tested. This hydrocooler was developed to supply economical post harvest cooling for growers that do not have the large production necessary to justify the commercial hydrocooling units presently available. Besides its significantly lower cost, this unit employs several features that also lowers the per unit cooling costs significantly. Laboratory experiments have shown that of the several methods tested, hydrocooling by total immersion was the fastest, most through and most energy efficient hydrocooling method. The NCSU hydrocooler embodies a two million BTU thermal storage battery that significantly lowers the capital and operating cost of the unit.
Low-Input Cooling and Shipping System for Small Fruit. Five years of tests have been completed on an improved cooling and shipping system for small, high value fruit such as blueberries, brambles and cherry tomatoes. The system consists of an insulated container capable of holding approximately 500 pounds of fruit which is connected to a small portable air conditioning unit. After a period of cooling, the air conditioner is disconnected. The reusable insulated container is capable of holding the chilled fruit at an acceptable temperature overnight or during transportation to market. The quality of cooling that results from this system is identical to that from a stationary facility costing thousands of dollars more.
Improved Post harvest Handling of Horticultural Crops. This project has focused primarily on the heat and mass transfer of horticultural crops cooling. Ongoing research conducted at many locations including several research stations has focused on cooling difficult to cool crops including sweet corn, melons and peppers and cucumbers in pallet bins.
Instrumented Sphere. Mechanical damage to sweet potatoes during grading and packing was shown in some preliminary studies to be a major contributing factor in the reduction of quality and shelf-life. An instrumented sphere, a device developed by USDA researchers at Michigan State University was used to evaluated sweet potato packing lines for sources of mechanical damage. More than half of the state's sweet potato packing lines were evaluated. The results of these evaluations suggested that most of the damage was occurring during bin dumping or box filling. Individual reports were provided to the owners of each facility evaluated. Additionally, the general information from this study was the subject of more that a dozen grower meetings and the subject of several newsletter articles.
Greenhouse Heating System Contamination. The use of greenhouses for transplant production has resulted in many question concerning the environmental control of these structures. Of primarily interest has been air contamination by pollutants generated by improperly designed and maintained heating systems. In cooperation with the county Extension staff and faculty member in the Department of Horticultural Science, air samples were taken and analyzed when there were suspected problems. In many cases, problems were identified and corrective measured recommended that reduced or eliminated the problem. This information was made available in a variety of ways including grower meetings, publications and popular press articles.
Mini-Float Beds for the Production of Vegetable Transplants. Growers with small acreages of vegetables have not been able to enjoy the economic benefits of greenhouse transplant production. In order to make this technology available to small growers, applied research and extension work was conducted to demonstrate small heated structures for this purpose. More than a dozen on-farm tests were conducted to demonstrate this technology. A popular press article presenting this information prior to the 1992 growing season resulted in more than 600 written requests for plans and information.
Analysis of Greenhouse Storm Damage. A winter storm of March 1993, caused over $5 million in damage to North Carolina farm structures, principally transplant greenhouses. Wind damage generally occurred in the eastern part of the state with snow damage more prevalent in the west. Engineering analysis and wind tunnel tests were conducted to determine the exact nature of the structural failures and to devise measures to reduce damages in the future. Verification of both calculations and wind tunnel tests were used to determine that in most cases, the root cause of the damage was inadequately built foundations. These recommendations have since been incorporated into new design standards and guidelines used by manufacturers and growers.
Contents