NOVELTY - The method of depositing a cadmium sulfide buffer layer from a solution to an exposed surface of a solar cell absorber layer of a workpiece for manufacturing solar cells, comprises placing the workpiece in a deposition chamber of a deposition system, flowing a supply solution at a predetermined rate into and through the deposition chamber and onto the exposed surface, depositing the buffer layer material on the exposed surface by heating the absorber layer, and flowing the used solution to a solution container (22) at another rate corresponding to the predetermined rate.    USE - The method is useful for depositing a cadmium sulfide buffer layer to an exposed surface of a solar cell absorber layer of a workpiece for manufacturing solar cells (claimed) and modules belonging to Group IBIIIAVIA compounds, where the Group IB is copper, silver, gold, the Group IIIA is boron, aluminum, gallium, indium, titanium and the Group VIA is oxygen, sulfur, selenium, tellurium and polonium.    ADVANTAGE - The method increases materials utilization of the chemical bath deposition processes, reduces waste, and allows continuous, low-cost deposition of materials on substrates with high-throughput.    DETAILED DESCRIPTION - The method of depositing a cadmium sulfide buffer layer from a solution to an exposed surface of a solar cell absorber layer of a workpiece for manufacturing solar cells, comprises placing the workpiece in a deposition chamber of a deposition system, flowing a supply solution at a predetermined rate into and through the deposition chamber and onto the exposed surface, depositing the buffer layer material on the exposed surface by heating the absorber layer, flowing the used solution from the deposition chamber to a solution container (22) at another rate that corresponds to the predetermined rate, cooling the used solution to a first temperature of 15-40 degrees C within the deposition chamber by cooling the deposition chamber wall, preparing renewed supply solution in the solution container using the used solution cooled to the first temperature, and directing another flow of the supply solution into the deposition chamber to provide further deposition of the buffer layer material using some of the renewed supply solution. The supply solution is maintained at the first temperature before entering the deposition chamber, and includes all chemical components of the buffer layer material and a sulfur source. The solar cells formed as the flexible workpiece is advanced through a roll-to-roll system. The buffer layer material is deposited at a second temperature of 50-90 degrees C, thus causing the transfer of heat from the solar cell absorber layer to a portion of the supply solution that is in contact with the exposed surface, where deposition of the buffer layer material transforms the supply solution to a used solution by depleting a predetermined amount of the chemical components in the supply solution including the sulfur source. The preparation of the renewed supply solution comprises adding the predetermined amount of the chemicals to the used solution. The cooling step is carried out by a cooler as the used solution is flowed between the deposition chamber and the solution container. The used solution is filtered to remove particles after the deposition of the buffer layer material. The heating of the solar cell absorber layer is performed by a resistance heater, a hot liquid jacket or an infrared lamp heater. The rest of the supply solution is maintained substantially at the first temperature during transferring heat from the solar cell absorber layer to the portion of the solution that is in contact with the exposed surface. The predetermined rate is 0.1-10 liters/minute. The sections of the flexible workpiece is took up from the buffer layer deposition chamber and wrapped up around a receiving roll at the predetermined moving rate of 100-1000 cm/minute. The heat is applied to the section of the solar cell absorber layer from a heater (29) placed across from the exposed surface section. An INDEPENDENT CLAIM is included for a system for depositing a buffer layer material from a process solution onto an exposed surface of a solar cell absorber layer.    DESCRIPTION OF DRAWING(S) - The diagram shows a sketch of a buffer layer deposition system.    Deposition section (21)    Solution container (22)    Feed line (23)    Filters (25A)    Cooling loop (27)    Heater. (29)