Selection of Thermal Insulation Thickness of Cold Store Enclosures

Abstract

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 O_c , O_d and the minimum cost ( P_min ) 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 analysis