Modelling and dynamic simulation of solar heat integration into a manufacturing process in Reunion Island

According to the International Energy Agency, solar thermal energy is rarely used in industrial sector, despite its capacity to generate heat with the existing technologies. Moreover, a large part of the firms of Reunion Island are in the food-processing industry, which is the most heat consuming sector according to these studies. Among them, the Sorelait-Danone company (yoghurt production) has decided to collaborate so as to analyze the potential impact of solar heat integration into its actual heat generation system. The company has a fuel boiler which generates 7 bar saturated vapor (corresponding to a temperature of 165 degrees C) at a nominal flow rate of 2,5 tons per hour. This boiler is supplied by a tank filled with water. In the latter, condensate coming from the process unit is mixed with the district's cold water, in order to compensate the vapor lost in the process. In this work, possibilities in terms of solar heat integration into the system have been investigated. 4 different cases have been simulated (direct or indirect integration, into the mixing tank or the boiler tank) and the corresponding saved fuel quantities have been estimated. The results of simulation show that in the best case, a fuel saving of 25 % can be expected with a total collector area of 600 m(2) for this company. (C) 2016 The Authors. Published by Elsevier B.V.