Solar heat storage unit and no-water tank solar water heater formed thereby

The utility model provides a solar heat storage unit and a no-water tank solar water heater formed by the solar heat storage unit. The solar heat storage unit comprises a stainless steel pipe, wherein, an inward convex structure is formed at the upper end part of the stainless steel pipe, and the inward convex structure, an end socket and sealing material can form upper sealing; the bottom of the stainless steel pipe is inserted in a water storage tank base with a water inlet and a water outlet; an outward convex structure is formed at the lower end part of the stainless steel pipe; a sealing ring is arranged among the outward convex structure, the water storage tank base and the outer wall of the stainless steel pipe; a lock nut used for tightly pressing the convex structure is also arranged on the water storage tank base; a vacuum heat accumulating pipe covered on the stainless steel pipe is connected with the lock nut, so as to form a solar heat storage unit; in addition, a water outlet pipe of the previous heat storage unit is connected with a water inlet pipe of the next heat storage unit, so that the individual heat storage units are connected in series so as to form the no-water tank solar water heater with no water tank. The solar heat storage unit and the solar water heater do not occupy useful space, achieve high heat absorption efficiency, can adopt the building integrated design, and can also form a solar heating system.