NOVELTY - The system (1) has secondary channel elements (5) which are arranged vertical to primary channel elements (3) such that end portions of secondary channel elements are received in respective cut-outs of the side walls (12,15) of adjacent primary channel elements, so that grid of channel elements is intersected and interconnected channel structures are formed. The photovoltaic modules (100) are attached to the primary and/or secondary channel elements, and the adjacent channel elements are partially overlapped with primary and secondary channel elements to form a closed structure.    USE - Photovoltaic system installed in roof of house, carport and industrial building.    ADVANTAGE - The photovoltaic modules are arranged in such a way that they form a closed structure common with the channel elements, and no more special seal structures are required in the region of the single modules. The large-scale photovoltaic systems can be installed on roof surfaces in a simple manner. The secondary channel elements with end regions are extended partially into the primary channel element, resulting in a good and tight connection of channel structures. The carrier elements are provided without damage of the channel structures, so that good fastening of the channel elements at an appropriate sub-construction can be attained. The secondary channel elements do not influence idle operational sequence of liquids in the primary channel elements. The final assembly of the photovoltaic modules can be made easily. The simple structure of the channel elements is formed integrally with the spring tabs by punching. The closed structure is better sealed so that no water enters into the channel elements during heavy rain. The photovoltaic unit is covered by frame elements so that the problems of backwater, contamination and pollution in snow and ice can be completely avoided. The top of photovoltaic unit and the top of frame lie in the same height, so that easy drainage of fluids, snow and ice is enabled. The risk of damage to the photovoltaic unit during assembly of the module frame can be prevented. The photovoltaic module can be mounted simply, and the fixing element is protected against environmental influences by space.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for method for manufacturing photovoltaic system.    DESCRIPTION OF DRAWING(S) - The drawings show the plan view and sectional view of the photovoltaic system.    Photovoltaic system (1)    Primary channel element (3)    Secondary channel element (5)    Sidewalls of primary channel element (12,15)    Photovoltaic module (100)