Solar Assisted Absorption Machine for the Fermentation Cooling and Maceration Heating Processes in the Winemaking Industry

Abstract

Two of the key processes in winemaking are alcoholic fermentation and must maceration, both of which have a high demand of energy. Fermentation is an anaerobic process carried out by the metabolic action of a microorganism. During this process the temperature has an important effect on the fermentation kinetics [1,2]. As the fermentation is exothermic, most of the wineries use a cooling system composed of mechanical refrigeration cycles and cooling towers in order to control the process temperature. After the fermentation, the must is macerated at temperatures close to 30°C, during which the phenolic materials (e.g. tanins and coloring agents) are leached and balanced. The aim of this study is to assess the thermal performance of a novel system composed of an absorption machine driven by solar and biomass energy sources, thus investigating the behavior of the system in an industrial winemaking process. This system consists of a lithium bromide absorption machine, a solar thermal collector field and a biomass water heater. The system operates in different modes during summer and winter seasons, taking advantage of the seasonality of both the solar resource availability and the heating and cooling demands of the processes. The results indicate that the proposed system is able to supply 25% of the cooling demand during the summer and between 30 to 50% of the heating demand during the winter.