Modular panel for laying in underfloor and wall heating systems and thermoconductive sheets for the same

The invention relates to a modular panel (100; 200) consisting of thermal insulation material for laying in underfloor or wall heating systems. Said panel comprises a flat rectangular base body (1) and cavities for accommodating thermal conduits (3). The cavities are configured as a grid-type arrangement of channels (2), consisting of several intersecting, rectilinear channels (2.1.1, ..., 2.1.n; 2.2.1, ..., 2.2.n) that run parallel to the lateral edges, several rectilinear channels (2.3.1, ..., 2.3.n; 2.4.1, ..., 2.4.n) that likewise intersect and run diagonally and at least two rows (R1, R2) of arched channel sections (2.5.1, ..., 2.5.n), positioned mirror-symmetrically, the vertexes (S) of said arched channel sections facing towards the lateral edges and the respective ends (18.1, 18.2) of said sections being connected to the rectilinear channels. The intersecting channels (2.1.1, ..., 2.1.n; 2.2.1, ..., 2.2.n) that run parallel to the lateral edges (11.1, ..., 11.4) are located at equal distances (A) from one another. The channels running diagonally intersect at intersection points (P1), said channels are equidistant (D) - measured diagonally - from the intersection points (P2) of the channels that run parallel to the lateral edges. The invention also comprises a surface heating system, such as an underfloor heating system, containing at least one modular panel and at least one thermoconductive sheet element.