Selective solar energy tunnel for exterior wall surface

The invention relates to a selective solar tunnel used for an external metope, consisting of a light-gathering body which can absorb thermal insulation air, a heat-absorbing plate which is arranged at the bottom of the light-gathering body, and a transparent top cover which seals the light-gathering body. Selective reflection is generated according to the difference of the solar altitude; the solar altitude is low in winter, thereby light beams are all reflected into the solar tunnel and the radiant energy of the light beams is converted into heat energy; the solar altitude is high in spring, in summer and in autumn and particularly in summer, the light beams are all reflected out of the tunnel and no heat is absorbed. The selective solar tunnel has a simple structure and low cost and has no moving element. Various selective building elements can be conveniently and beautifully prepared by embedding a plurality of selective solar tunnels in the form of arrays into external surfaces such as building blocks, thermal insulation tiles, external wall panels and so on. A building built by application of the elements can absorb solar energy in winter, thereby the building reduces and even completely bears heating heat load; in summer, the building can be prevented from receiving solar radiation and be insulated, thereby the heat load of an air conditioner is reduced; the energy consumption of the building is greatly reduced; and the energy is saved.