Life Cycle Assessment Of Solar Water Heating System With Evacuated Tube Collector And Flat Plate Collector

Increasing energy consumption in buildings has given more attention to renewable sources such as solar energy.Solar hot water system,as one of the most mature solar thermal utilization technology,has been widely used and promoted.But if consider from the perspective of life cycle,what is the environmental performance of solar water heating system,and what is the difference between the life-cycle environmental impacts of the two most-used collectors,the evacuated tube collector and the flat plate collector? Based on the existing research,the paper takes two types of solar water heating system as research objects,and a monitoring platform has been built first to monitoring the operation effect,then the life cycle impact assessment is carried out by the means of simulation.First,in order to obtain the data of solar hot water system in operation stage,a monitoring platform of solar hot water system was set up by analyzing the demand,selecting the data transmission mode,determining the hardware and system design the functions of data collection,date remote transmission,date storage and display have been realized.Secondly,a simulation model of solar hot water system was established by using TRNSYS software,then the two kinds of solar hot water system were simulated respectively.The results show that the collector efficiency is positive correlated with solar radiation.The annual average collecting efficiency of the solar water heating system with evacuated tube collector is 42.9%,which is lower than that of the solar water heating system with flat plate collector,47.1%,while the actual collecting efficiency of the solar water heating system with evacuated tube collector is higher,which is calculated based on the lighting area instead of the total area.And the annual heat collection and energy consumption of the two systems have been obtained.At last,the life cycle assessment of two systems was carried out,the goal and scope of the study were identified first,and the inventory analysis of the two solar hot water systems was carried out.Then,GaBi software was used to conduct modeling and life cycle impact assessment.The results show that among the life cycle environmental impacts of the solar water heating system with evacuated tube collector,the type with the largest share of environmental impact is the abiotic depletion potential of fossil(ADP fossil),accounting for 32%,while the type with the largest share of the solar water heating system is abiotic depletion potential of elements,reaching 64%.When yielding the same amount of heat,the environmental impact value of the solar water heating system with flat plate collector is 1.6 times as much as that of the solar water heating system with evacuated tube collector.Compared to the positive environmental impact by the heat collection,the environmental impacts of other stages are few.For the solar water heating system with evacuated tube collector,the life cycle environmental impact is only 6.4%(relative to gas heating)and 1.7%(relative to electrical heating)of the positive environmental impact of heat collection,for the solar water heating system with flat plate collector,this figure is 10.3%(relative to gas heating)and 2.8%(relative to electrical heating).The results show that the environmental benefits of solar hot water system are quite significant,and the system with evacuated tube collector is superior to the system with flat plate collector in terms of the life cycle environmental impact.