Abstract: A boiler for a solar receiver includes a first boiler panel having a plurality of tubes fluidly connecting an inlet header of the first boiler panel to an outlet header of the first boiler panel. The first boiler panel tubes form a first solar receiver surface. A second boiler panel has a plurality of tubes fluidly connecting an inlet header of the second boiler panel to an outlet header of the second boiler panel. The second boiler panel tubes form a second solar receiver surface. The first and second boiler panels are adjacent one another, a portion of the first boiler panel and an end of the first solar receiver surface overlapping an end of the second boiler panel to reduce solar radiation passing between the first and second solar receiver surfaces. A plurality of boiler panels may be arranged in rectangular or cylindrical orientation about a boiler central axis.

Abstract: An improved burner (4) for fuel oil and fuel gas with low NOx production, wherein the combustion air is subdivided in three streams and with flow rate control swirlers in each air streams. The stream of primary air is intercepted by a swirler comprising an array of radially fixed tabs (15) mounted in correspondence to the outlet section in the combustion chamber (3), while the secondary and tertiary air swirlers comprise tabs (18, 19) turnable around axes disposed perpendicular and parallel to the central axis of the burner, respectively. The primary and secondary air inlets have a variable, continuously adjustable section. Furthermore, there are provided mass rate meters (24, 25) near the outlet section of the secondary and tertiary air streams in the combustion chamber (3) substantially unaffected by the vorticity induced by said swirlers.