A solar thermoaccumulator, including a parallel battery of closed-circuit vacuum solar pipes, and provided with a plurality of accumulation bulbs, which are either immersed in a primary conductive fluid that circulates in an annular chamber having an air space, whose internal wall is the containing wall of a reservoir containing a fluid to be heated; or are put in direct thermally conductive contact with tubular tangs that are attached to and inserted in a reservoir, is disclosed. The reservoir may be single reservoir, or may be associated with and sequentially in fluid communication with at least one other upstream, parallel aligned reservoir.