Panel with longitudinal mirrors for a solar power plant

Abstract

A receiver for a solar power plant with mirrors ( 7 ) and horizontal longitudinal receivers ( 1 ) includes a rotating shaft and axis of symmetry which ( 14 ) are parallel to a longitudinal axis of the radiation receiver. The receiver is formed by a balanced expansion and pressure collector, the tubes ( 19 ) of which are grouped in a separate central bundle ( 20 ) and adjacent bundles ( 21 and 22 ), thermally insulated from one another longitudinally. Heat transfer fluid circulates first through both adjacent bundles in parallel, to then be injected into the central bundle, where the radiation intensity received is greater because of receiving the radiation from the array of mirrors focused on the midline of the active face ( 2 ) of the receiver, each bundle of tubes being able to be covered by a separate ( 60, 61, 62 ) transparent window ( 28 ).

1 . A receiver with longitudinal mirrors for a solar power plant, based on a balanced expansion and pressure collector or receptacle receiving radiation from an array of concave mirrors parallel to one another, having a markedly longitudinal geometry with a greater length than width which can rotate about a longitudinal axis of symmetry, which in turn is an axis serving as support in bearings, which are placed on at intervals pillars are buried in the ground and rigidly support the bearings, therefore the securing shaft, which is a rotating shaft, is always fixed in a straight line position, each mirror being orientated for reflecting radiation towards at least one longitudinal solar receiver, the longitudinal axis of symmetry thereof located at a height above the height of the axis of the mirror closest to the receiver as a result of columns or pillars supporting the receiver, with an active face receiving radiation reflected by the mirrors; said receiver having a longitudinal geometry and a greatest length parallel to the longitudinal axes of the mirrors, and having an angle of inclination transverse to the horizontal, there being a final mirror furthest from the receiver, two fields of mirrors being able to be assembled symmetrically with respect to two parallel receivers with active faces arranged opposite one another, each face pointing to a field, in assemblies in which the longitudinal axes follow a local meridian, and being assembled both to the north and to the south of the receiver in cases in which the longitudinal axes of the mirrors are parallel to a local astronomical latitude, in which assemblies can also be two parallel receivers with active faces arranged opposite one another, each face pointing to a field, and in which positions and angles are expressed in a coordinate system in a working plane used, which is always normal to the longitudinal assembly axes, which are parallel to one another; and a y-axis of the coordinate system in the working plane being a vertical line passing through a central or mid-point of the segment representing the active face of the receiver in the working plane, and an x-axis being a horizontal line passing through the central point of the segment which, in the working plane, represents the mirror closest to the receiver, with a transverse width of the active surface or face of the receiver selected from a value in the order of 1% of a straight line distance between the central point of the furthest mirror of the field and the central point of the active surface of the receiver; selecting an angle of vision of the central point of the receiver from the central point of the furthest mirror in a range of values between 10° and 80°, measured on the horizontal of the location; and the inclination of the active face of the receiver being determined with the segment marking said surface in the working plane being perpendicular to a bisector of the field, said bisector being at an angle formed with the lines going, respectively, from the central point of the active face of the receiver to the central point of the mirror closest to the receiver, and to the central point of the furthest mirror; a group of controllable pumps and valves being arranged which are external to the receiver but essential for the operation of the invention to force heat transfer fluid to follow required movements through the hydraulic circuits of the receiver; the solar radiation reflected by the different mirrors finally striking a receiver inside of which there are arranged longitudinal tubes through which a heat transfer fluid feeding a thermal application circulates; the active face of the receiver being the outer surface of the tubes where the radiation strikes, or the active face, where the radiation strikes, being thermally connected with the surface of the tubes, which are grouped in at least three separate bundles, transversally, there being a central bundle of longitudinal tubes, and at least two adjacent bundles and, one on each side of the central bundle, the bundles being able to go in the same receptacle or in adjacent receptacles, but without mixing heat transfer fluid streams when passing through the receiver, the central bundle and adjacent bundles and having longitudinal thermal insulation between one another separating the bundles; and the percentage distribution of the total active surface of the receiver between the central bundle of tubes and the adjacent bundles and being a value selected from the central bundle occupying 99% of the active surface, and the adjacent bundles and occupying the rest; and the central bundle occupying 20%, the adjacent bundles and occupying the rest; giving 50% of the active surface occupied by the central bundle as a distribution reference value and the adjacent bundles ( 21 ) and each occupying 25% of the total active surface of the receiver on either side, wherein the bundles of longitudinal tubes of the receiver are arranged obliquely to one another, the angle through which the radiation arrives being covered by the active surface of the tubes as a result of the covering provided by the bundles, there being a small area in which a shadow of the end of one bundle is cast on a contiguous bundle, with an extension no greater than half the radius of the tube in the shadow, without physical contact between the ends of both bundles, and thermal insulation parts further preventing passage of convection currents being able to be interposed between them without physical contact with both at the same time if there is filling gas in the receptacle of the receiver. 
     
     
         2 . The receiver with longitudinal mirrors for a solar power plant according to  claim 1 , wherein in assemblies with two symmetrical receivers and with faces opposite one another, the fluid is received from the pipelines supplying the receiver from thermal application and is circulated through the adjacent bundles of the first face, which is the face receiving less radiation intensity; and after that first passage the fluid passes to the adjacent bundles of the other receiver by an outer connection, through which bundles, the fluid circulates thus ending a pre-heating phase in which values of peripheral areas of the radiation sent by the field of mirrors and striking the active face of the receiver are harnessed; the fluid from the adjacent bundles of the second receiver then entering into the central bundle of the first receiver through an outer connection, where levels of concentrated radiation are higher in intensity, being measured in watts per unit of surface area, making the fluid acquire higher temperatures as the fluid passes through said bundle, and greater heating is completed when the fluid passes through the central bundle of the second receiver, which the fluid reaches from the central bundle of the first receiver, through another outer connection, and from which the fluid exits through the outer duct to go to an thermal application.