Bridge type large-capacity high-concentrating-ratio composite Fresnel line concentrating and reflecting device

Abstract

The invention relates to a solar heat collector with a focusing element, in particular to a bridge type large-capacity high-concentrating-ratio composite Fresnel line concentrating and reflecting device which is structurally characterized in that a main reflecting device comprises a plurality of micro-arc Fresnel reflecting mirrors, the micro-arc Fresnel reflecting mirrors are arranged above a heat collecting pipe are distributed like a bridge which comprises a horizontal section as well as a left arc section and a right arc section which are symmetric to each other relative to the horizontal section, an auxiliary reflecting device is arranged below the heat collecting pipe, and the arc concave surface of the auxiliary reflecting device faces to the heat collecting pipe. The Fresnel line concentrating and reflecting device has the advantages that: high ground utilization rate can be achieve, the sunlight incidence situation is fully considered so that the sunlight loss is reduced greatly, the heat collecting effect of the heat collecting pipe is improved, good effects of focusing and heating the heat collecting pipe uniformly are achieve, and the large-capacity focusing effect is reflected.

Description

technical field [0001] The invention relates to a solar heat collector with focusing elements, in particular to a bridge-type large-capacity and high-concentration-ratio composite Fresnel line light-concentrating reflector. Background technique [0002] The Fresnel lens has the function of concentrating light. In the application of large-scale concentrating devices for solar thermal power generation, reflective Fresnel equipment is mainly used. There are many types of Fresnel reflectors in the prior art, such as the widely used compact linear Fresnel reflector (CLFR for short), which consists of a plurality of compactly arranged Fresnel reflectors distributed below The composition of the mirror and the solar heat collecting tube on the top refers to the patent, ZL200880112788.8; there is also a parabolic trough concentrating device, which is also a commonly used solar thermal power concentrating device. A solar collector tube is set at the gathering position above the conca...

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Problems solved by technology

[0003] Yet the existence of above-mentioned concentrating device has many weak points: the capacity of tower type concentrating device and parabolic dish type concentrating device is little, and the capacity of parabolic trough type concentrating device is higher than tower type concentrating device and parabolic dish type concentrating device. The large one is the one commonly used at present, but it usually does not exceed 100MW, while the capacity of CLFR can be made larger and the cost is lower

[0005] Secondly, the radian of the reflector of CLFR is not adjustable at present. 1. The reflector in the middle part is relatively close to the heat collecting tube, while the reflectors on both sides are far away from the heat collecting tube. If all the reflectors have the same radian, it is bound to be There will be some reflectors with poor focusing effect; 2. Although the reflector can rotate with the change of sunlight angle, the distance between the center of the reflector and the center of the heat collector tube is constant, but the focal length of the reflector varies with the incident angle of sunlight. position will change, as attached figure 2 And attached image 3 , when the sunlight and the reflector form an angle of 30° (see attached image 3 ), its focusing distance (the distance from the center of the reflector to the center of focus) is only when the sunlight is perpendicular to the reflector (see attached figure 2 ) half

[0006] In addition, the heat collecting tube of CLFR is only heated on one (lower) side, and the heating is uneven, which affects the temperature and heat absorption of the heat collecting tube

[0007] Fresnel line concentrating reflectors with secondary reflection can reduce the loss of sunlight, but only at the collector, Reflectors have some of the same problems as CLFR, resulting in limited improvement, improved The effect is uncontrollable (that is, different incident angles of sunlight are different. In fact, if the concentration is accurate, the secondary reflection device is not needed, but it is difficult to achieve horizontally arranged reflectors, unless the reflection angle changes. The radian also changes), and the upper part of the secondary reflector will also block the sunlight

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