NOVELTY - The system has a photovoltaic (PV) cell module (104) positioned at a non-sun-collecting side of a primary reflector (102). An adjustable sunray distributing optical mechanism (I) is arranged at a sun-collecting side of the reflector, and distributes sunrays (a, b) redirected to the non-sun-collecting side to the module. A portion of sunrays ranging from 0 to 100 percentage is reflected to a heat collecting element (101), and remaining sunrays are directed and distributed to the module through openings (107) in the reflector and the mechanism after the sunrays irradiate to the reflector.    USE - Interchangeable and fully adjustable solar thermal PV concentrator system for generating solar thermal energy and PV electricity for small industry, residential and commercial applications.    ADVANTAGE - The system enables separately meeting specific temperature and concentration requirements of the heat collecting element and the PV cells to optimize efficiency, energy output and applications for the system. The heat collecting element and the PV cells are separated so that a solar thermal receiver can be operated at higher temperature of above 70 degree Centigrade than the PV cells and the PV cells can be cooled to lower temperature of below 70 degree Centigrade to optimize efficiency of the system. The system allows flexible design of exposed areas of the PV cells or cell modules and an attachment layout to reach optimal sun intensity or concentration ratio for the PV cells by using a non-sun-collecting side of the primary reflector. The PV cells and electronics are protected from dust, water and environmental pollutants in operating positions by placing the PV cells on the non-sun-collecting side and by enclosing the PV cells in a closed structure. The system is switchable so as to take available solar energy and land resources and to provide flexibility in energy utilization such as primarily solar thermal energy, primarily electric power from PV cells and portion of energy, from each source, thus facilitating improved efficient utilization and diversified use of space for solar energy and reduced cost of integrated solar thermal and solar power generation. The system adjusts proportions of the sunrays directed to the heat collecting element and the PV cells at an unlimited degree of freedom, thus maximizing efficiency of the PV cells or thermal energy required by a particular application such as absorption chiller. The system has modular design, thus enabling applications of large-capacity combined energy plants.    DETAILED DESCRIPTION - The reflector is linear-focus or point-focus concentrating reflector. The reflector is formed in flat, Fresnel, curved, parabolic and quasi-parabolic shapes.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a primary linear parabolic concentrator with a sunray directing optical mechanism and a sunray distributing optical mechanism that direct and distribute sunlight to a non-sun-collecting side of a primary reflector.    Sunrays (a, b)    Heat collecting element (101)    Primary reflector (102)    Secondary reflector (103)    PV cell module (104)    Tertiary reflector (105)    Light tunnel (106)    Opening of primary reflector (107)