阳能热水器结构图:1、水箱外壳(Water tank shell)2、保温层(Layer for heat preservation)3、水箱内胆(Inner water tank)4、排气溢流孔(Vent holeand overflow hole)5、密封胶圈6、外水箱端盖(End cover of the outer tank)7、防尘圈(A loop of dustproof)8、电加热器