2 research outputs found
Selection of Thermal Insulation Thickness of Cold Store Enclosures
This paper aims to set a mechanism in order to calculate the economical thickness of thermal insulation layer of external walls of cold storage plant based on a comprehensive techno-economic analysis of thermal insulation cost, in addition to the cost related to the production of necessary refrigeration to compensate for heat flow through the exterior walls into the cold storage and conservation plant. Some research that dealt with this topic provided techno-economic analysis for the cost of thermal insulation and the production of refrigeration based on exterior walls area of the cold storage plant, which does not make sense, and that it is difficult to determine the effect of the operational expenses. Therefore, the present study stems from the idea that the cold storage and conservation plant is dedicated to prolong the period of food conservation, so the course of techno- economic analysis has been shifted to take into account one ton of food stuff stored in cold storage and conservation plant to be refrigerated and conserved instead of considering the external walls area. In addition, this paper provides a more accurate formula to calculate the specific cost of refrigeration equipment bx in order to skip the percentage of mistake used to occur in calculating the overall standard heat transfer coefficient of external walls caused by applying the weighted average value of the specific cost of refrigeration equipment bxa. The obtained results resulting from the use of a computer-programmed method in techno-economic analysis of the cost enhanced the fact that the impact of cold storage plant capacity and specific cost of refrigeration equipment on the economical thickness of the insulation layer is correct. This justifies the concept proposed in this paper that associates the techno- economic analysis of costs to be the capacity of the cold storage plant instead of the exterior walls area unit, where obvious decease in the values ??of the operational cost Oc , Od and the minimum cost ( Pmin ) with the increase cold storage and conservation plant capacity. The results also show that economically optimal thermal resistance ( Ro.ec ) of heat transfer through the exterior walls and the economic thickness of insulation layer have been effected by the specific cost of refrigeration equipment . It has been noticed that bx decreases from 0.94- 0.54 with increase of the cold storage plant capacity from 400 to 5000 ton. This leads to 6% decrease in economically optimal thermal resistance and the economical thickness of the insulation layer. Keywords: thermal insulation, economical thickness, techno-economic analysi
Textural Quality and the loss in Nutrients of Potatoes and Carrots Affected by Blanching and Storage Conditions
As potatoes and carrots are important horticultural products and an important raw material for the food processing industry, so inevitably it is stored in fridges in order to be available all year long. Texture is a critical quality factor for vegetables. Successful production of acceptable products requires serious attention to textural changes and attaining of this aim involves a good knowledge of the factors that influence texture. Both the textural and the loss in nutrients of processed vegetables are influenced not only by variety and maturity at harvest, but by processing and storage conditions as well. Blanching combined with cold storage is an excellent preservation method to extend vegetables shelf-life. While many of the researchers in this area investigated the properties of those of thermally processed (sterilized, dehydrated, frozen) products, little attention has been given to the interactive nature of the stages in the various processing operations or to variations within a particular stage. The objective of this study was to investigate the effects of different blanching and storage conditions on textural and loss in nutrients of potatoes and carrots. Before Potatoes and carrots were frozen using plate and air blast, the samples were blanched using water and steam blanching with time variations within each method. The physical properties of interest were hardness, cohesiveness, and loss of sugar. The loss in sugar determined and the texture changes in the products during processing are illustrated. Keywords: loss in nutrients of potatoes, blanching, storage condition