Comparison Study Of Environmental Effects Between Solar Water Heating System And Coal-fired Boiler System With LCA

Life Cycle Assessment (LCA) is a new tool of environmental management and analysis that develops during these years. It's an effective method to assess the environmental load of products, processes or activities in the whole life cycle from raw materials acquisition to its production, transportation, distribution, utilization, maintenance and disposal. In this dissertation, LCA was applied for the first time to compare the environmental effects between Solar Water Heating System and Coal-fired Boiler System from raw materials acquisition to system production, utilization and disposal. The results show that the key process of environmental pollution for the Solar Water Heating System is raw materials production in the product manufacturing process and that of the Boiler System is coal consumption in the running process. After lots of data processing and calculating, the result shows that to produce 1kWh of energy, the Boiler System will produce 411.75g of CO2, 11.48g of NOx, 4.89g of SO2 and 28.03g of TSP, and the Solar Water Heating System will produce 31.66g of CO2, 0.10g of NOx, 0.27g of SO2 and 0.66g of TSP, which is respectively 1/13, 1/115, 1/18 and 1/42 that of the Boiler System. So we can make conclusions that the improvement of environmental air quality resulting from the utilization of Solar Water Heating Systems is remarkable.Another innovation of this dissertation is that TRACI (Tool for the Reduction and Assessment of Chemical and other Environmental Impacts) model and Analytical Hierarchy Process (AHP) are applied into LCA study to assess the comprehensive effect combining with the economic and technical indexes. Results show that when emphasis was particularly given to the environmental effect, the weight of Solar Water Heating System is 0.6368 and that of the Boiler system is 0.3632, which shows that the comprehensive effect of Solar Water Heating System is better than that of the Boiler System. And when emphasis was particularly given to the economic effect, the weight of Solar Water Heating System is 0.4768 and that of the Boiler system is 0.5232, which shows that the comprehensive effect of Solar Water Heating System is a little bit worse than that of the Boiler System at this situation. In this dissertation, the application of LCA was discussed elementarily through comparison study of the environmental effects between two specific systems. During study we found that LCA is a scientific assessment methodology and it can play a good role in directing Cleaner Production and Environmental Management. We believe that LCA will be applied widely in the sustainable development strategies study and environmental management in future.