Modelling ventilated potato bulk storage facilities

Abstract

The potential of improving the conventional potato bulk storage process is accelerated through this thesis by defining, calibrating and validating a spatially distributed storage model that includes multiple quality aspects. The calibration and validation was performed using large-scale experimental data. Potatoes are one of the world's staple foods. While their crops are seasonal, the demand for them is continuous, resulting in the need to store them and keep them well. As the climate conditions surrounding stored potatoes influence potato quality and vice versa, climate control is an efficient way to influence product quality. Potato storage facilities therefore widely use climate control to limit losses during storage. However, good climate conditions do not automatically guarantee a high-quality end product. At present, climate control in conventional storage facilities is based on rules of thumb, gathered by trial and error and through experiments that mainly can only be evaluated once a year. Because of that, and also as a result of the increased range of potato varieties, each with its own properties, as well as of changes in growth, climate and storage conditions, finding the optimal storage climate conditions is an art and science that advances very slowly. The use of product quality control in addition to climate control was already proposed in the early 2000s, but is still not yet widely applied in commercial storage facilities due to a gap in insights into particularly the spatial distribution of how multiple quality aspects develop during storage. The aim of this research was to fill a vital gap in the knowledge on how climate and the product quality development of potatoes interact during bulk storage, by developing a spatially distributed mathematical storage model, analysing the simulation results, and evaluating these with respect to experimental data from industrial bulk storage facilities. In this thesis in particular the temperature, moisture content and reducing sugar content interaction and development in a conventional bulk storage, with a cellar and perforated floor and ventilation capacities of 100-150 cube air per cube product per hour, is evaluated and theoretically improved. A 2-D and 1-D climate-product quality model for the evaluation of the complete bulk storage process are presented in this thesis. This study particularly concerns conventional bulk storage facilities for frying potatoes, but the research is also of value for different types of storage facilities and different agro-materials.