Central receiver solar system comprising a heliostat field

摘要

The aim of the invention is to build central receiver solar power plants in which the heliostat fields can be used more efficiently. To achieve said aim, a heliostat field consisting of a near field having a uniform reflector surface density ρ of more than 60% is preferably combined with a far field whose reflector surface density ρ decreases as the distance from the receiver increases. The invention also comprises central receiver solar power plants which consist exclusively of a near field having a uniform reflector surface density ρ of more than 60%. The high reflector surface density ρ in the near field and in areas of the far field is achieved by the use of heliostats having rectangular reflectors and a rigid horizontal axle suspension (FHA) or, alternatively, by heliostats having rectangular reflectors and a rigid quasipolar axle suspension (FQA). The heliostat field concentrates the solar radiation on a receiver whose target surface, aperture, thermal absorber or photovoltaic absorber has a normal vector which is directed downward to the heliostat field that extends below the receiver in the directions North, East, South and West. The receiver is mounted in a suspended manner to a support structure that extends over the heliostat field.

主权项

1. A method for the design of a heliostat field of a central receiver solar system, comprising the following steps:
a) wherein, in the first step, a setup of heliostats is defined for a near field on a preferably level overall ground surface, having a reflector surface density p of p>60%,
wherein the reflector surface density p is defined as the ratio of the overall reflector surface of a region of the heliostat field to the built-over ground surface of the same region of the heliostat field,wherein each heliostat has a reflector that can be moved about two rotary axles, which reflects the solar radiation onto the target surface of one or more receivers during the changing position of the sun,wherein the target surface is configured as an aperture or a thermal absorber or a photovoltaic absorber of the respective receiver, and the normal vector of the target surface of the receiver is directed downward, preferably perpendicular, onto the heliostat fieldwherein each heliostat has a first rotary axle and a second rotary axle perpendicular to the first rotary axle and is arranged on a mounting surface,wherein the first rotary axle is rigidly arranged relative to the mounting surface and the second rotary axle relative to the reflector,wherein for each heliostat the first rotary axle is configured parallel to the mounting surface and a group of heliostats with a common mounting surface are set up in a row, so that the first rotary axle of the heliostats in the particular group lie on the same line, i.e., are aligned with each other,wherein the reflector of each heliostat is rectangular and preferably longer in the direction of the second rotary axle than in the direction perpendicular to it and b) wherein the common mounting surface of one or more groups of heliostats can be inclined to the overall ground surface by an angle α dependent on the position to the receiver,
wherein in the second step the positions of the heliostats are determined with the distance from the receiver, calculating how far the near field with the same reflector surface density p reaches around the receiver andwhere the far field then begins at the near field,wherein in the far field the distances in the east-west direction and north-south direction must be increased to prevent or reduce the mutual blocking of the heliostats as much as possible,wherein blocking means that a heliostat at least partly covers the beam path from the reflector of an adjacent heliostat to the target surface of the receiver, c) wherein in the third step the radiation power which the respective heliostats transfer onto the target surface of the receiver is calculated and preferably those heliostats are chosen for the heliostat field that contribute at the designed time or other determined times the highest component to the radiation power on the target surface of the receiver,
wherein the heliostat field is formed at least by a near field and, depending on the required radiation power on the target surface of the receiver, also a far field,wherein, if a receiver height HR of at least 100 m is chosen, a far field is provided and the largest diameter DH of the heliostat field is preferably less than six times the receiver height HR,wherein in the fourth step a support structure is chosen, which is suitable to holding the receiver in the defined position above the heliostat field, this support structure being configured as
i. an arch,ii. or a trussiii. or a suspended cable construction,wherein these three support structures i, ii and iii, each with at least two footpoints that are preferably located in the outer region or outside the heliostat field,
iv. or a cranelike support system with a jib or cantilever arm supporting the receiver, which extends across the heliostat field,wherein one or more footpoints of the cranelike support system is located either in the outer region or preferably outside of the heliostat field on the side of the receiver facing away from the equator,wherein the position of a receiver mounted on the jib can be changed in up to three dimensions,so that for the heliostat field determined in the third step different positions can be chosen for the receiver for particular positions of the sun in order to increase the efficiency of the heliostat field for the respective positions of the sun.