Energy analysis of cooling tower and metal holding tanks at Chassix

Abstract

In this thesis, two different methods were used attempting to estimate heat loss from metal holding tanks and chutes at Chassix Norway. The first method uses thermal resistance to calculate the total heat loss without any measurements, while the second calculates the conductive, convective and radiative heat loss separately using surface temperature measurements. Resulting heat loss for one year was 605.65 MWh without measurements and 827.64 MWh after surface temperature measurements. Heat loss calculated using measurements is the most accurate, as it relies on fewer assumptions. Additionally, a model was created in Aspen Plus with basis in a cooling tower at Chassix, attempting to analyze the operations of the cooling tower using the distillation column block RadFrac. The process of finding the VLE (Vapor Liquid Equilibrium) diagram for water and air was presented, with the intention of using the McCabe-Thiele method to find the number of equilibrium stages suitable for the model. However, the VLE diagram proved unreasonable to use in the McCabe-Thiele method. The model was therefore run with a reasonable amount of equilibrium stages, based on an example model. This did not yield any useful results and it was clear the model did not run as intended. Despite this, simulating and analyzing a cooling tower in Aspen Plus should be possible as it has been done before, albeit with a more complex method.