Minimizing greenhouse gas emissions through the application of solar thermal energy in industrial processes

The analysis of industrial energy usage indicates that low temperature processes (20 approximate to 200 degrees C) are used in nearly all industrial sectors. In principle there is the potential to use solar thermal energy in these lower temperature processes thus, reducing the environmental impact of burning fossil fuels. Using the model of an Austrian dairy plant, this research investigated the potential for, and the economic viability of, using solar energy heat processes in industry. Some industrial sectors such as food, chemistry, plastic processing, textile industry, building materials industry and business establishments can be identified as potential sectors for the application of solar energy heat processes. When assessing the (economic) feasibility of solar thermal energy, the investigation of these industries' energy systems has to focus on an integrated analysis of cooling and heating demands and to take into account competing technologies. Amongst these are heat integration, cogeneration, new technologies and heat pumps. Pinch analysis was used to investigate industrial energy systems and heat integration possibilities and proved to be a viable tool. Working from the basis of energy balances, Sankey diagrams, pinch analysis and environmental cost accounting, a newly developed investigation tool was applied in the case study of an Austrian dairy plant. This enabled a fast optimization of the system. Two different options for the integration of solar thermal energy into the production line were calculated, option I with a solar field of 1000 rn 2 and option 2 with a solar field of 1500 m(2). Natural gas savings of 85,000 for option 1 and 109,000 m(3)/a for option 2 can be achieved, resulting in a reduction of 170 tons Of CO2 per year, or 218 tons for options I and 2 respectively. Based upon option 1, return on investment is realised after less than three years of implementation. This research thus, indicates promising technical and economical feasibility of using solar thermal energy for industrial processes and provides an important step towards sustainable zero emission production in industry. (C) 2006 Published by Elsevier Ltd.