CN105509340B - A kind of solar thermal collection system that aggregation light beam is transmitted using light guide cable - Google Patents

Abstract

The present invention proposes a solar heat collection system that uses light guide cables to transmit concentrated light beams, which can collect large-scale sunlight and form a high-temperature temperature field inside the heat absorber to heat the working fluid; the heat collection system is mainly composed of arc-shaped condensers, Composed of light guide head, light guide cable, light receiving head and heat absorber; the arc concentrator gathers the parallel sunlight at its own focus, and guides the collected light into the light guide cable through the light guide head. Using the principle of total reflection, the light is transmitted through the light guide cable to the The light receiving head installed on the heat sink guides the light to the inner chamber of the heat sink through the light receiving head; a large number of curved condenser mirrors form an array, and the sunlight collected by each curved condenser mirror is transmitted to the In the inner chamber of the heat absorber, the light output from the end of all the optical cables is superimposed inside the heat absorber and irradiated on the working medium and the inner wall surface to form a high temperature. After the flowing working medium is heated, the heat is taken out to realize solar heat collection and utilization. Especially suitable for solar thermal power plants.

Description

A solar heat collection system using light guide cables to transmit concentrated light beams

technical field

The invention belongs to the technical field of solar heat collection and power generation, and in particular relates to a solar heat collection system which adopts an optical cable to transmit concentrated light beams.

Background technique

On the one hand, the level of human energy consumption continues to increase, on the other hand, conventional fossil energy is increasingly exhausted, and the pollutant emissions associated with conventional fossil energy are increasingly unable to meet people's demand for future energy. Solar energy, as an inexhaustible new clean energy, is getting more and more attention, and the development of solar energy is making progress day by day. Among them, solar power generation is an advanced development and application of solar energy. It converts solar energy into electrical energy through certain means to meet the electricity demand of modern society. Currently popular solar power generation is mainly divided into two forms: photovoltaic power generation and solar thermal power generation. Among them, photovoltaic power generation uses solar panels or battery thin films to receive sunlight and directly convert light energy into electrical energy, but there are great shortcomings in terms of power generation efficiency and battery life. Solar thermal power generation can be divided into trough solar thermal power generation, tower solar thermal power generation and butterfly solar power generation. Because the trough solar thermal power generation is not high in concentration, the temperature of the steam generated is low, so the power generation efficiency is restricted. Butterfly solar power generation is composed of a number of scattered small-scale concentrating power generation devices, and the power of a single unit is small, which is also not conducive to the improvement of the overall power generation efficiency. The tower solar thermal power generation uses many reflectors to gather a large area of sunlight on a heat absorber, so it can get a very high temperature, so that the initial temperature of the steam in the power generation system can be increased, and a higher power generation can be obtained. efficiency.

Solar thermal power plants are usually built in sparsely populated desert areas. The main reason is that the solar thermal field needs a flat and unobstructed open land, which is convenient for arranging a large number of reflectors and building a heat collecting tower with a certain height in the center to absorb heat. The heater is arranged on the central tower to receive the sunlight reflected from the surrounding ground mirrors and convert the light into heat to heat the working fluid. At present, an important factor that limits the improvement of thermal power generation efficiency is the efficiency of thermal towers. In order to obtain greater power and a higher temperature field, it is necessary to use more condensers to concentrate more sunlight on the heat absorber on the top of the heat collection tower. At the same time, in order to receive reflections from more reflectors If there is no light, the heat collecting tower needs to be built very high, which is extremely unfavorable for engineering construction and equipment operation. Moreover, due to the influence of the cosine effect, the tower heat collection cannot fully and effectively utilize the solar energy in the heat collection field. It is of great significance to develop a new collector system, reduce the height of the heat absorber and increase the utilization rate of solar energy to reduce the cost of collector power generation and improve the reliability of the power plant.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a solar heat collection system that uses light guide cables to transmit concentrated light beams, so as to collect and concentrate a large area of sunlight in the heat absorber to realize photothermal High-efficiency conversion; the heat generated by the heat absorber is mainly used to heat and produce high-temperature steam, which is used to drive the steam turbine to generate electricity. The invention can also be applied in other fields requiring heat energy such as seawater desalination.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A solar heat collection system that uses light guide cables to transmit concentrated light beams, including:

heat sink 25;

Several light-receiving heads 8 arranged on the heat absorber 25;

A curved condenser lens array composed of a plurality of mutually independent curved condenser lenses 21;

A light guide head 22 arranged at the focal position of each curved condenser lens 21;

And several light guide cables 23 connecting the light guide head 22 and the light receiving head 8 to collect the transmission light in the chamber of the heat absorber 25 .

Each light-receiving head 8 corresponds to one or more light-guiding heads 22 , and each light-guiding head 22 corresponds to only one light-receiving head 8 .

Each curved condenser 21 has a focal point, and has an automatic day-by-day system to control the curved condenser 21 to align with the direction of the sun, so that the projection section of the curved condenser 21 is always perpendicular to the sun's rays, and receives the sun's rays to the greatest extent and gathers the rays in focus.

The light guide cable 23 utilizes the principle of total reflection, and the light propagates forward in the medium of the light guide cable 23 through continuous total reflection, and the light guide head 22 serves as the light entrance of the light guide cable 23 .

The ends of all the light guide cables 23 are connected to the light receiving head 8, and the light receiving head 8 receives the light beam transmitted along the light guide cable 23 and introduces it into the chamber interior of the heat absorber 25, and the incident light spot is superimposed inside the heat absorber 25, A high temperature field is formed.

The heat absorber 25 is arranged on the ground in the center of the site instead of on the high tower, and each curved condenser lens 21 is arranged around the heat absorber 25 .

The cable core of the optical guide cable 23 is composed of two layers of light guide media with different refractive indices, which are respectively the central medium and the cladding medium. The light rays at the interface between the central medium and the cladding medium will be totally reflected, so that the light in the central medium Sunlight propagating inside will not cause loss due to refraction.

The heat absorber 25 is a double-layer structure composed of the heat absorber outer shell 2 and the heat absorber inner shell 6. An outer chamber 10 is formed between the inner wall of the heat absorber outer shell 2 and the outer wall of the heat absorber inner shell 6 to absorb heat. An inner chamber 11 is formed in the inner shell 6 of the heat absorber, and the bottom end of the inner shell 6 of the heat absorber protrudes downwards outside the shell 2 of the heat absorber through an inlet guide pipe 13, as a refrigerant inlet 9, and the inner shell 6 of the heat absorber The top of the top protrudes upwards to the outside of the heat absorber shell 2 through the outlet guide tube 5, as the thermal medium outlet 4, the light receiving head 8 is installed outside the heat absorber shell 2, and the light guide cable 23 is transmitted through the light receiving head 8 Concentrated sunlight is connected to the outer chamber 10, and the outer wall of the inner shell 6 of the heat absorber mainly absorbs sunlight to convert high-temperature heat energy and heat the working fluid.

The outer wall surface of the heat absorber shell 2 is laid with an insulating layer 1, the inner wall surface is laid with a reflective layer 3, the outer wall surface of the heat absorber inner shell 6 is laid with a heat absorbing coating 7, and the heat absorber inner shell 6 is provided with ribs and spoiler12.

When the heated working medium is an opaque medium, no holes are opened on the part of the inlet guide pipe 13 and the outlet guide pipe 5 located in the outer chamber 10, and the heated working medium enters the inner chamber 11 from the inlet guide pipe 13, After the inner chamber 11 is heated, it flows out through the outlet guide pipe 5;

When the heated working medium is a transparent medium, holes are opened on the part of the inlet guide pipe 13 and the outlet guide pipe 5 located in the outer chamber 10, and a part of the heated working medium enters the inner chamber 11 from the inlet guide pipe 13 , while the other part enters the outer chamber 10 from the hole on the inlet guide pipe 13 , the working fluid is heated at the same time in the inner chamber 11 and the outer chamber 10 , and finally mixes and flows out in the outlet guide pipe 5 .

Compared with prior art, the beneficial effect of the present invention is:

1. The present invention removes the restriction that the traditional tower-type solar heat collection system must place the heat absorber at a high place on the top of the tower. The heat absorber can be arranged on a lower platform or on the ground according to the needs of the site, which greatly reduces the engineering difficulty. It is convenient for overhaul and maintenance, and improves the system stability.

2. Each curved concentrator is directly aimed at the sun, regardless of the position and angle of the heat sink, so the cosine effect can be greatly reduced, the utilization rate of sunlight can be increased, and the land occupation area of the heat collection field can be reduced.

3. The concentrated solar beam does not irradiate the outer wall of the heat absorber, so an insulation layer can be laid on the outer wall of the heat absorber, which greatly reduces the external heat dissipation loss of the heat absorber, and is conducive to increasing the temperature of the heat absorber and improving the utilization efficiency of solar energy.

4. The use of light pipes to transmit solar energy concentration can easily increase the degree of concentration of the heat absorber, thereby increasing the temperature of the heat absorber, so that steam with higher parameters can be produced to drive the steam turbine to generate electricity, and ultimately achieve higher power generation efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention.

Fig. 2 is a schematic structural view of the heat absorber of the present invention.

detailed description

The implementation of the present invention will be described in detail below in conjunction with the drawings and examples.

As shown in FIG. 1 , the heat collection system of the present invention is composed of a curved condenser lens 21 , a light guide head 22 , a light guide cable 23 , a light receiving head 8 and a heat absorber 25 . The system adopts a large number of curved condenser mirrors 21 arranged to form a curved condenser mirror array. Each curved condenser mirror 21 has the same specification and is arranged around the heat absorber 25 according to a certain rule.

Each curved concentrator 21 can gather the parallel sun rays on its own focal point. The light guide head 22 is positioned at the focal point of the curved concentrator 21. The light guide head 22 is connected to one end of the light guide cable 23, and the other end of the light guide cable 23 is the end. The light receiving head 8 is connected, and the light receiving head 8 is connected with the heat absorber 25 . Each curved surface condenser 21 is equipped with its own light guide head 22 and light guide cable 23. Accompanying drawing 1 only symbolically draws eight curved surface condensers 21. In actual engineering applications, the number of curved surface condensers 21 depends on the power of the heat collection system. The number of curved condenser mirrors 21 in the present invention is not limited to eight.

The light guide head 22 is used to guide the convergent light from the focal point to the light guide cable 23. Using the principle of total reflection, the converged light is transmitted through the light guide cable 23. The end of the light guide cable 23 is connected to the light receiving head 8 on the heat absorber 25, and the light receiving head 8 The transmitted light beam is guided to the inside of the heat absorber 25 . The light beam output from the end of the optical cable 23 is superimposed and concentrated inside the heat absorber 25 , and is absorbed by the light-to-heat conversion coating inside the heat absorber 25 to form a high temperature, which is used to heat the working fluid in the heat absorber 25 .

The working principle of the present invention is:

In the array of curved condensers, each curved condenser 21 can work independently, or the day-by-day tracking system can uniformly control the curved condensers 21 to align with the sun, so that the projection section of the curved condensers 21 is always perpendicular to the sun’s rays to maximize the reception Sun rays, after being reflected by the arc condenser mirror 21 , the sun rays are converged at respective focal points of the arc condenser mirror 21 .

The light entrance end of light guide cable 23 is connected with light guide head 22, and light guide head 22 is installed on the focal point of curved surface condenser 21, and the sunlight collected by arc surface condenser 21 enters light guide cable 23 through light guide head 22 and propagates along light guide cable 23.

The light guide cable 23 works on the principle of total reflection. The cable core is composed of two layers of light guide media with different refractive indices, namely the central medium and the cladding medium. Sunlight propagating in the central medium will not be lost due to refraction.

The end of the light guide cable 23 is connected to the light receiving head 8 . Each light receiving head 8 can be connected with a plurality of light guide cables 23 at the same time, and the light receiving head 8 guides the light beams from the light guide cables 23 into the inner chamber of the heat absorber 25 .

The structure of the heat absorber 25 has been specially designed, and it is generally a chamber structure surrounded by a metal shell. A light-to-heat conversion coating is laid on the inner wall of the chamber of the heat absorber 25, and the chamber is filled with working fluid. The light beams injected into the chamber of the heat absorber 25 through the light receiving head 8 are superimposed on each other and irradiated on the working medium and the chamber wall in the chamber. It can be converted into high-temperature heat energy, and the working medium is heated. Since the outer wall of the heat absorber does not receive concentrated sunlight, thermal insulation materials can be laid to reduce the heat dissipation loss of the heat absorber.

A structural form of the heat absorber 25 is shown in Figure 2, which is provided with a two-layer structure of a heat absorber outer shell 2 and a heat absorber inner shell 6, and a heat absorbing coating 7 is provided on the outer wall of the heat absorber inner shell 6, which is The main area that absorbs and gathers sunlight to generate high-temperature heat energy has a reflective layer 3 on the inner wall of the heat sink shell 2 to reduce the absorption and conversion of light energy by the wall surface of the heat sink shell 2 and reduce the wall temperature. The outer wall surface of 2 is laid insulation layer 1, in order to reduce the external heat dissipation loss of heat absorber. An outer chamber 10 is formed between the inner wall of the heat absorber shell 2 and the outer wall of the heat absorber inner shell 6 , and an inner chamber 11 is formed in the heat absorber inner shell 6 .

A light-receiving head 8 is installed on the shell 2 of the heat absorber to guide the collected solar beams transmitted by the light guide cable from the light collector to the outer chamber 10 of the heat absorber, and irradiate the outer wall of the inner shell 6 of the heat absorber to realize Photothermal conversion. There is a guide pipe between the heat absorber outer shell 2 and the heat absorber inner shell 6 to guide the working fluid into and out of the chamber, specifically, the bottom end of the heat absorber inner shell 6 passes through the inlet guide pipe 13 downwards The top end of the heat absorber inner shell 6 protrudes upwards to the outside of the heat absorber shell 2 through the outlet guide tube 5 as the heat working medium outlet 4 .

According to the different properties of the working medium, it is decided to open or not open holes in the two guide tubes, so that the heated working medium flows through the inner chamber 11 and the outer chamber 10 of the heat absorber or only from the inner chamber 11 to realize metal heating. Cooling of the wall and heating of the working fluid.

The working principle of heat absorber 25 is:

The heat absorber 25 is arranged on the ground at the center of the solar concentrating system, and the external light guide cable 23 transmits the solar beams gathered by multiple concentrators. The light receiving head 8 is installed on the heat absorber shell 2 according to certain rules, and the light guide cable Connected with the light receiving head 8 on the heat absorber shell 2 , the light receiving head 8 transmits the light beam to the space of the outer chamber 10 and finally illuminates the outer wall surface of the heat absorber inner shell 6 . There is a heat-absorbing coating 7 on the outer wall of the heat absorber inner shell 6 to enhance the ability of the wall to absorb sunlight. The inner wall of the heat absorber shell 2 has a reflective layer 3, and the reflective layer 3 reflects and radiates the light reflected and radiated from the outer wall of the heat absorber inner shell 6 back to the outer wall of the heat absorber inner shell 6 to increase the thickness of the heat absorber inner shell 6. Improve the light and heat utilization efficiency of the wall and reduce its radiation loss.

Depending on the nature of the heated working fluid, it is determined whether or not to open holes in the pipe sections where the inlet guide pipe 13 and the outlet guide pipe 5 pass through the outer chamber 10 .

When the working medium to be heated is a medium with poor light transmission (generally referred to as opaque medium), no holes are opened in the inlet guide pipe 13 and the outlet guide pipe 5 , and the heated working medium is isolated from the outer chamber 10 . The heated working medium enters the inner chamber 11 from the cold working medium inlet 9 and is heated, and then flows out through the hot working medium outlet 4. The purpose of the ribs and deflectors 12 installed on the inner wall of the heat absorber inner shell 6 is to increase the contact between the metal wall surface and The heat exchange area of the working fluid generates turbulence to the working fluid, which can enhance the heat exchange between the heated working fluid and the inner shell 6 of the heat absorber.

When the working medium to be heated is a medium with strong light transmission (generally refers to transparent medium, such as water and heat transfer oil, etc.), holes are opened on the inlet guide pipe 13 and the outlet guide pipe 5 . In addition to the heated working fluid flowing through the inner chamber 11 to absorb heat, a part of the working fluid enters the outer chamber 10 through the hole on the inlet guide pipe 13 to absorb heat from the outer wall of the heat absorber inner shell 6, and This part of the working fluid itself is irradiated by the light beam and directly absorbs part of the solar energy. Therefore, the working fluid flowing through the outer chamber 10 is heated simultaneously by the outer wall surface of the heat absorber inner shell 6 and the sunlight. The working fluid in the inner chamber 11 and the outer chamber 10 finally mixes in the outlet guide pipe 5 and flows out of the heat absorber. An insulation layer 1 is laid on the outer wall of the heat absorber shell 2 to reduce the external heat dissipation loss of the heat absorber.

All arc concentrating mirrors 21 carry out the same work process, therefore, the inside of heat absorber 25 has gathered the very high sun's rays of density, if further increase the quantity and the area of arc concentrating mirror 21, then can further improve the heat absorber 25. Concentration. The sunlight gathered inside the heat absorber 25 irradiates the working medium and the inner wall of the heat absorber 25 to form a high temperature, and is cooled by the flowing working medium, and the working medium itself is heated and then flows out of the heat absorber. So far, the working process of the solar heat collection system converting light energy into heat energy of the working medium is completed.

The invention adopts the light guide cable to transmit the sunlight collected by the curved surface condenser to the heat absorber, replacing the traditional way of directly reflecting sunlight to the heat absorber arranged on the central tower by adjusting the angle of the plane reflector, reducing the The cosine effect improves the concentration and flexibility of the system, and changes the form of the heat sink, changing the light received from the outer surface of the traditional heat sink to the light received from the inner cavity, which greatly reduces the heat dissipation loss of the heat sink.

Claims (6)

1. A kind of 1. solar thermal collection system that aggregation light beam is transmitted using light guide cable, it is characterised in that including：

   Heat dump (25)；

   Some chengguang heads (8) being arranged on heat dump (25)；

   The cambered surface optically focused lens array being made up of multiple separate cambered surface condensers (21)；

   It is arranged on the guide-lighting head (22) of each cambered surface condenser (21) focal position；

   And some light guide cables that the guide-lighting head (22) of connection and chengguang head (8) collect in transmission ray in heat dump (25) chamber (23)；

   The heat dump (25) is the double-decker that is made up of heat dump shell (2) and heat dump inner casing (6), heat dump shell (2) exocoel (10) is formed between inwall and heat dump inner casing (6) outer wall, inner cavity chamber (11) is formed in heat dump inner casing (6), inhales The bottom of hot device inner casing (6) extends downwardly from heat dump shell (2) outside by inlet honeycomb duct (13), as cold working medium entrances (9), The top of heat dump inner casing (6) extend out to heat dump shell (2) outside upwards by exporting mozzle (5), is exported as hot working fluid (4), chengguang head (8) is arranged on heat dump shell (2) outside, is transmitted light guide cable (23) and next convergence by chengguang head (8) Sunshine, which connects, leads to exocoel (10), and is mainly absorbed sunshine conversion high temperature heat by heat dump inner casing (6) outside wall surface and added Hot working fluid；

   The heat dump (25) is arranged on place center ground rather than high tower, and each cambered surface condenser (21) is arranged in heat absorption Around device (25)；

   The outside wall surface laying heat-insulation layer (1) of the heat dump shell (2), internal face laying reflector layer (3), heat dump inner casing (6) Outside wall surface laying heat absorbing coating (7), be provided with floor and spoiler (12) in heat dump inner casing (6)；

   When heated working medium is transparent medium, then it is located at exocoel (10) in inlet honeycomb duct (13) and outlet mozzle (5) Part on perforate, be heated a working medium part and enter inner cavity chamber (11) from inlet honeycomb duct (13), while another part is from entering Hole on mouth mozzle (13) enters exocoel (10), and working medium is heated, finally existed simultaneously in inner cavity chamber (11) and exocoel (10) Outlet mozzle (5) is mixed and flowed out.
2. 2. according to claim 1 using the solar thermal collection system of light guide cable transmission aggregation light beam, it is characterised in that described Each chengguang head (8) corresponds to one or more guide-lighting head (22), and each guide-lighting head (22) only corresponds to a chengguang head (8).
3. 3. according to claim 1 using the solar thermal collection system of light guide cable transmission aggregation light beam, it is characterised in that described Each cambered surface condenser (21) has a focus, and has automatic system day by day, control cambered surface condenser (21) alignment solar direction, Make cambered surface condenser (21) projecting section vertical with sunray all the time, at utmost receive sunray and come together in light Focus.
4. 4. according to claim 1 using the solar thermal collection system of light guide cable transmission aggregation light beam, it is characterised in that described Light guide cable (23) utilizes total reflection principle, and light is propagated forward in light guide cable (23) medium by constantly total reflection, guide-lighting head (22) light entrance as light guide cable (23).
5. 5. according to claim 1 using the solar thermal collection system of light guide cable transmission aggregation light beam, it is characterised in that all Light guide cable (23) end be both connected on chengguang head (8), chengguang head (8) receive along light guide cable (23) transmission light beam simultaneously By introducing heat dump (25) chamber interior, launching spot is superimposed inside the heat dump (25), forms temperature field.
6. 6. according to claim 1 using the solar thermal collection system of light guide cable transmission aggregation light beam, it is characterised in that described The cable core of light guide cable (23) is made up of the different light-conductive media of two layers of refractive index, respectively central medium and covering medium, in The interface light of heart medium and covering medium can be totally reflected, so that the sunshine propagated in central medium will not be because Cause to be lost for refraction.