CA2880605A1

CA2880605A1 - Solar power-generation system

Info

Publication number: CA2880605A1
Application number: CA2880605A
Authority: CA
Inventors: Stephane Labelle
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-02-25
Filing date: 2015-02-25
Publication date: 2016-08-25

Description

SOLAR POWER-GENERATION SYSTEM
FIELD OF THE APPLICATION
[0001] The present application relates to power generation using solar energy, and more particularly to the use of solar energy tb heat a power-generating medium.
BACKGROUND OF THE ART

[0002] Solar power is a largely untapped source of energy.

[0003] Since we receive 6000 times more energy from the sun in comparison to global human consumption. In some dry regions of the world, power may be extracted from the sun rays on a continuous basis, due to weather systems with low levels of humidity in the atmosphere. Since most other technologies else than linear Fresnel use less than 50% of the solar energy available and are using more expensive technologies to do so.
We chose to improve the performance of linear Fresnel both on the concentration level and the percentage of energy collected.

[0004] Linear Fresnel technology is the most efficient land use solar concentration technology since it can cover all the area available on the ground combined with the most simple control system since it work only on one axes. But until now it did not have a good optical efficiency and a poor level of concentration. It is therefore an aim of the present disclosure to provide a novel solar power-generation system and method capable of achieving much higher optical efficiency and higher levels of concentration while keeping this system at its present level of simplicity. Another aim is to provide a better energy collection system using heat transfer fluids working at near to ambient pressure capable of transporting and storing this energy in tanks so we can in most cases generate mechanical energy and or electricity 24 hours a day 365 days a year.

[0005] It is therefore desirable to create solar power-generation systems with increase absorption of solar energy.
SUMMARY OF THE APPLICATION
mow Actual design of Fresnel concentration technology is based on lessons learned from through solar concentration experiences. It has been learned that using a vacuum glass tube around the collector greatly increases the efficiency of these systems by diminishing the heat loss by convection. This is why they are using a glass window to keep convection losses at a minimum without much success since it is impossible to create vacuum due to important surface involved in these collectors. The pressure on the glass would represent a total pressure of 569470 ton of pressure per m2 of surface. Due to the refraction indices of the glass the utilization of this glass in these collector systems had to be oriented on the north south axes otherwise the solar energy would have been reflected when the angle of the sun in the sky would have been greater than 400 at the beginning and at the end of the day.
The results of our research in optic have demonstrated that placing the reflectors on the north south axes almost completely eliminates the focal ability of these reflectors since the sun moves on 180' on the east ouest axe and the reflectors need to be displaced on 90 (+450 and -45 ) to concentrate the solar energy on the collector. This is why these systems are using almost completely flat mirrors on their reflectors. They need to use a secondary reflector on top of the collector or use many pipes covering a large surface to compensate for the lack of focal capacity of these concentrators. Furthermore the results of our research on the thermodynamic aspect of the collector have demonstrated that it is much more efficient to use insulated panels 51 covered with reflective surfaces under these panels placed at an angle of more or less 45 to keep the thermal losses by convection at the minimum and reflect the solar energy on the receiver.
The increase of the focal capacity of this new system is critical to improve its efficiency on the thermodynamic aspect since using an energy-receiving fluid capable of remaining liquid at ambient pressure at temperatures around 600 C
reduces the capital cost, eliminates many risks related to high pressure steam and makes it easy to store this liquid in a storage tank at ambient pressure to help produce mechanical energy or electricity 24 hours a day and follow the demand instead of generating electricity only when solar energy is available. Since we can easily obtain high level of concentrations with this new optimized linear Fresnel concentration and collection system. In one of our energy generation systems. We will use latent heat of the see salt to stabilize the boiling temperature of water and help improve the thermodynamic efficiency of this Rankin cycle. One of the storage tanks could be field with see salt. We will pressurize this see salt in a tank and introduce see water in ideal proportions to obtain high pressurized pure steam and harvest the see salt from the bottom of this tank in a liquid state.
[0007] This same linear Fresnel concentration system will also improve the efficiency and reduce the capital cost when using Photovoltaic panels to convert solar energy to electrical power. The same shape of collector will be used covered with photovoltaic cells. A heat transfer fluid will be used to stabilize the operating temperature of the photovoltaic cells and all the heat collected will be used later on for heating buildings or other processes. It is considered to concentrate the solar energy on photovoltaic panels to increase their expose to luminosity and heat.
However, , photovoltaic panels are sensitive to heat in that they lose efficiency with rising temperatures. In some instances, photovoltaic panels may stop producing electricity altogether or may sustain damage with high temperatures.

Moreover, photovoltaic panels efficiency is lowered by heat and must instead be cooled to work more efficiently.
[0008] It is therefore an aim of the present disclosure to provide a novel solar power-generation system and method.
[0009] Therefore, in accordance with the present application, there is provided a solar power-generation system comprising at least one mirror displaceable in at least one degree of rotation, a hollow pipe in which circulates an energy-receiving medium, and means to actuate the at least one degree of rotation of the mirror to reflect solar rays onto the hollow pipe to heat the energy-receiving medium, and a circuit comprising the hollow pipe, the circuit having means to extract energy from the energy-receiving medium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Fig. 1 is a block diagram of a solar power-generation system in accordance with an embodiment of the present disclosure;
[00111 Fig. 2 is a schematic view of mirror units and a pipe with solar panels of the solar power-generation system of Fig. 1;
[0012] Fig. 3 is a schematic view of a cleaning unit for mirrors of the mirror units of the solar power-generation system of Fig. 1;
[0013] Fig. 4 is a perspective view of a mirror unit with pipes of the solar power-generation system;
[0014] Fig. 5 is a schematic view showing the reflection of rays on the pipe by the mirror units;
[0015] Fig. 6, 7, and 7.1 are a sectional view of a pipe portion of the solar power-generation system, in accordance with yet another embodiment.
[0016] Fig. 8,9 and 10 is a perspective view of a mirror unit system.

[00V] Fig.
11,12,13,14 are schematics view of the same solar concentration system used to improve the amount of solar energy available in the greenhouse or collected with the energy collector to store heat into a water tank so provide heating during night time.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0als]
Referring to the drawings, and more particularly to Fig. 1, there is illustrated a solar power-generation system in accordance with an embodiment of the present disclosure.
The system 10 has mirror units 11 that are used to concentrate the sun rays to produce heat and/or electrical power.
[0019] The heat produced using the mirror units 11 is collected by a power-generation circuit 12. The power-generation circuit 12 may be in a heat-exchange relation with a refrigerant line 13 that is used to absorb heat from the medium circulating in the power-generation circuit 12.
Referring concurrently to Figs. 1 and 2, the power-generation circuit 12 has a solar-energy receiver 20, constituted of a pipe portion 20B with solar panels 20A
(optional). The solar panels 20A are typically flat photovoltaic panels that are commonly used to transform solar power into electrical power, and may or may not be provided as apart of the solar-energy receiver 20. A heat-conducting compouncrmay be used to immovably secure the solar panels 20A
to the pipe portion 20B, such that a medium circulating in the pipe portion 203 may cool the solar panels 20A while absorbing heat. As will be described hereinafter, the various mirrors of the mirror units 11 are typically in the form of elongated slats, adjustable in orientation to ensure that a high amount of solar rays are directed to the solar-energy receiver 20.
[0021] . The medium (a.k.a., refrigerant) circulating in the pipe 203 goes trough the various stages of the power-generation circuit 12. Accordingly, the refrigerant circulating in the pipe portion 203 will absorb heat from the concentration of sun rays on the pipe portion 20B, or from the solar panels 20A in the embodiment featuring such panels, thereby cooling them and rendering them more efficient.
[0022] In an embodiment, the medium/refrigerant is a liquid, such as water, that may change phases at various stages of the power-generation circuit 12. The water may becomes Vapor after passing through the solar-energy receiver 20. In this case, the vapour, for instance in a superheated state, is directed from the pipe portion 20B to a turbine 21.
The turbine 21 is used to power an electricity-generating unit, among other possibilities. The medium/refrigerant at the exit of the turbine 21 is directed to the condenser 22.
The condenser 22 is used to release heat from the refrigerant.
[0023] , According to one embodiment, the circuit 12 is in heat exchange with a circuit 13, in which circulates an ice-water mix or fresh water. This water may be from a desalination process, as described in United States Provisional Patent Application No. 61/314,204, filed March 16, 2010. In another embodiment, the condenser 22 is a heat reclaim unit (e.g., heating water for domestic consumption), a standard water tower or any other system that allows heat to be released or recuperated. A pump 23 ensures that the medium/refrigerant circulates in this order in the power-generation circuit 12.
[0024] Although not shown, it is considered to use two different circuits in parallel and in heat-exchange relation to respectively collect the heat from the solar-energy receiver 20, and to operate the turbihe 21. For instance, it may be preferred to circulate oil or other heat transfer fluid in a closed circuit featuring the pipe 20B and have the oil or other heat transfer fluid pass through a heat exchanger to release heat to the medium circulating in the power-generation circuit 12. Such an operation may be performed in order to

-6 increase the amount of energy collected from the solar-energy receiver 20, or to heat the medium to a desired state (e.g., superheated steam) to actuate the turbine 21 the steam can be condensated at an ideal temperature to supply heating for building greenhouses FIG.11 or other processes when needed.
[0025]
Referring to Fig. 3, a cleaning unit 30 is provided to clean the mirrors of the mirror units 11 according to another embodiment. The cleaning unit 30 may be of the robot type, requiring few manipulations to install, and operating autonomously. In this manner, the mirrors of the mirror units 11 are cleaned to optimally direct rays to the solar-energy receiver 20. The cleaning unit 30 moves along the mirror of the mirror unit 11 in a given direction of travel. The cleaning unit 30 comprises a carriage 31 supporting the cleaning' equipment opposite the reflective surface of the mirrors, and guide rails 32 disposed opposite the non-reflective side of the mirrors, which guide rails 32 support the carriage 31 for translational movement thereon. The guide rails 32 may be electrical guide rails, so as to power the cleaning unit 30, via appropriate connection (not shown).
[00a] The carriage 31 is mounted to the guide rails 32 with wheelsets 33. One of the wheelsets 33 is connected to motor 34, so as to receive actuation therefrom. In the illustrated embodiment, a pulley or chain transmits the rotational output from the motor 34 to a rear one of the wheelsets 33, although other arrangements are considered as well.
[0027] A wiper or vacuum 35 projects from a surface of the carriage 31 and may contacts the mirror of the mirror unit 11.
Residue water may therefore be collected by the action of the wiper 35, and directed into a recuperation tank 36. A
flexible hose or any other appropriate types of piping may be used to convey the recuperated liquid from the tank 36 to

-7 filter 38 via pump 37. The filter 38 removes any solid residue.
[0028] A
cleaning water tank 39 may contain cleaning agents, with means to mix the cleaning agents with the water fed through the filter 38. A sponge or wiping unit 40 collects water from the tank 39 in order to apply it to the reflective surface of the mirror of the mirror unit 11. The sponge 40 may work by capillary action, or any other appropriate way. A vacuum 41 may also be used to suck in any dirt upstream. According to an embodiment, the vacuum 41 may be a cyclonic bag vacuum, as actuated by the action of one of the wheel sets 33.
[0029] Despite reusing its water, the cleaning unit 30 may be connected to a water supply, to make up for water lost due to evaporation. Any appropriate piping and conduits may be used to 'supply the cleaning unit 30 with water and cleaning agents. Also, the cleaning unit 30 may be solar powered, with suitable equipment. It is also considered to provide the cleaning unit 30 with a processing unit that will be programmed to run cleaning cycles periodically.
NOM
Referring concurrently to Figs. 4-6, there are illustrated various embodiments of the mirror units 11. It is observed, that there may be a plurality of the solar-energy receivers 20 with or without solar panels 20A. The pipes 20B
may be interconnected in series or in parallel. In the illustrated embodiments, the mirror units 11 feature a plurality of elongated mirror slats, also known as Fresnel mirrors, each rotatable independently from one another.
Accordingly, the reflection of rays may be focused and concentrated onto a focal axis, namely the pipe portion 20B.
Any other appropriate arrangement of mirrors is considered as well.
[0031] Referring to Fig. 7, there is illustrated a section of the solar-energy receiver 20, without solar panels. An

-8 insulation member 50 is provided on the top portion of the pipe and in strategic location portion 20. In an embodiment, the reflective panel 51 improves optical efficiency and reduce convection losses, to improve energy collection and reduce energy loss therethrough.
[00312] Referring to Fig. 8,9 and 10 there is illustrated a section of the solar-energy receiver 20, without solar panels.
An insulation member 50 is provided on the top portion of the pipe and in some strategic location portion 20. In an embodiment, the reflective panel 51 improves optical efficiency and reduce convection losses, to improve energy collection and reduce energy loss therethrough.

-9

Claims

CLAIMS: 1. A solar power-generation system comprising mainly a solar collection system oriented on the east west axes to improve level of solar energy concentration and thermodynamic efficiency:
at least one solar panel and or a hollow pipe to heat the energy-receiving medium and aninsulated panels 51 covered with reflective surfaces under these panels placed at an angle of more or less 45° to keep the thermal losses by convection at the minimum and reflect the solar energy on to the receiver, and a circuit comprising the hollow pipe, the circuit having means to extract energy from the energy-receiving medium to convert solar energy into mechanical energy or electricity;
at least one light-reflecting unit orientable on one axes to direct solar light onto at least one solar panel and or a hollow pipe including to heat the energy-receiving medium, and a circuit comprising the hollow pipe, the circuit having means to extract energy from the energy-receiving medium; and a hollow device having an inlet and an outlet through which circulates an energy-receiving fluid, the hollow device being connected to the at least one heat-transferring relation with at least.one solar collector and or the energy-receiving medium to absorb heat from at least one solar collector.
2. The solar power-generation system according to claim 1, wherein the hollow device is an elongated pipe having the inlet and the outlet at opposed ends and an insulated panels 51 covered with reflective surfaces under these panels placed at an angle of more or less 45° to keep the thermal losses by convection at the minimum and reflect the solar energy on the receiver.
3. The solar power-generation system according to claim 1, wherein at least one solar panel extends longitudinally along the elongated pipe mainly on the east ouest axes and an insulated panels 51 covered with reflective surfaces under these panels placed at an angle of more or less 45° to keep the thermal losses by convection at the minimum and reflect the solar energy on the receiver.
4. The solar power-generation system according to any one of claims 1 and 2, wherein the at least one light-directing unit comprises a plurality of reflectors reflecting light onto the at least one solar collector.
5. The solar power-generation system according to claim 4, wherein each of the reflectors is rotatably mounted to support posts to be rotated to an appropriate orientation relative to the at least one solar collector.
6. The solar power-generation system according to claim 5, wherein the supports posts are supported to a ground by at least one translation joint that is generally upright to arrange a height of each of the reflectors relative to adjacent ones of the reflectors.
7. The solar power-generation system according to any one of claims 4 to 6, wherein each of the reflectors has a low-density core with a reflective surface thereon.
8. The solar power-generation system according to claim 7, wherein the low-density core is made of at least one of at least one bee nest, and a metallic or rigid composite material coating envelops the low-density core.
9. The solar power-generation system according to any one of claims 4 to 8, wherein each of the reflectors has a reflective concave surface facing the at least one solar panel when reflecting solar light.
10. The solar power-generation system according to claim 2, wherein the light-directing unit is a single parabolic or cylindrical reflector, with the at least one solar panel being provided approximately along a focal axis of the parabolic reflector.
11. The solar power-generation system according to claim 2, wherein the light-directing unit comprises a first parabolic reflector, and a second parabolic reflector provided approximately along a focal axis of the first parabolic reflector, the at least one solar panel being positioned relative to the second parabolic reflector to receive an amount of light reflected by the second parabolic reflector.
12. The solar power-generation system according to claim 11, further comprising an elongated insulation mounted on a peripheral portion of the elongated pipe.
13. The solar power-generation system according to any one of claims 1 to 12, further comprising a heat-exchange circuit in which the energy-receiving fluid cycles, the hollow device being a heat absorption stage of the heat-exchange circuit.
14. The solar power-generation system according to claim 13, wherein the heat-exchange circuit comprises a turbine to produce mechanical energy from the heat-exchange circuit.
15. The solar power-generation system according to claim 13, wherein the heat-exchange circuit comprises a condensation stage in which the energy-receiving fluid is cooled by seawater pumped from the sea or an ice water mix.
16. The solar power-generation system according to any one of claims 1 to 15, further comprising at least one protective panel and articulated arms, the at least one protective panel being displaceable by the articulated arms between a shielding position in which the at least one protective panel shields the at least one solar panel, and a power-generation position in which the at least one protective panel is away from the at least one solar panel for solar light to reach the solar panel.
17. The solar power-generation system according to claim 16, wherein the at least one protective panel comprises a reflective surface, the at least one protective panel being located relative to the at least one light-directing unit to reflect light onto the at least one solar panel in the power-generation position.
18. A solar power-generation system comprising:
at least one photonic receiver;
an elongated vessel supporting the at least one photonic receiver and being in heat-transferring relation therewith;
a laser source aligned with the elongated vessel such that an output of the laser source passes through the elongated vessel for being excited by the at least one photonic receiver;
a first parabolic reflector having a concave solar-light reflecting surface;
a second parabolic reflector having a convex solar-light reflecting surface provided approximately along a focal axis of the first parabolic reflector to receive an amount of light reflected by the first parabolic reflector, the at least one photonic receiver being located approximately along a focal axis of the second parabolic reflector to receive an amount of light reflected by the second parabolic reflector.
19. The solar power-generation system according to claim 18, further comprising a second elongated pipe having an inlet and an outlet through which circulates an energy-receiving fluid, the hollow device being connected to the second parabolic reflector and being in a heat-transferring relation therewith for the energy-receiving medium to absorb heat from the second parabolic deflector.
20. The solar power-generation system according to claim 19, further comprising a heat-exchange circuit in which the energy-receiving fluid cycles, the second elongated pipe being a heat absorption stage of the heat-exchange circuit.
21. The solar power-generation system according to claim 20, wherein the heat-exchange circuit comprises a turbine to produce mechanical energy from the heat-exchange circuit.
22. The solar power-generation system according to any one of claims 18 to 21, wherein each of the reflectors has a low-density core with a reflective surface thereon.
23. The solar power-generation system according to claim 22, wherein the low-density core is made of at least one bee nest, and a metallic or rigid composite material coating envelops the low-density core.
24. The solar power-generation system according to any one of claims 18 to 23, comprising an optic fiber within the elongated vessel for receiving the output from the laser source.
25. A solar power-generation system comprising:
a hollow elongated pipe having an inlet and an outlet through which circulates an energy-receiving fluid, the hollow device having a surface portion with solar light absorbing properties, the energy-receiving medium absorbing heat from the elongated pipe; and at least one elongated light-directing unit orientable to direct solar light onto the at least one solar panel.
26. The solar power-generation system according to claim 25, further comprising an elongated hollow space concentric to the elongated pipe and located on another peripheral portion of the elongated pipe, the elongated hollow space being one of filled with inert gas and in a generally vacuumed condition.
27. The solar power-generation system according to any one of claims 25 and 26, wherein the at least one light-directing unit comprises a plurality of elongated reflectors reflecting light onto the at least one solar panel, the elongated reflectors being generally parallel to the elongated pipe.
28. The solar power-generation system according to claim 27, wherein each of the reflectors is rotatably mounted to support posts to be rotated to an appropriate orientation relative to the at least one solar panel.
29. The solar power-generation system according to claim 28, wherein the supports posts are supported to a ground by at least one translation joint that is generally upright to arrange a height of each of the reflectors relative to adjacent ones of the reflectors.
30. The solar power-generation system according to any one of claims 27 to 29, wherein each of the reflectors has a low-density core with a reflective surface thereon.
31. The ,solar power-generation system according to claim 30, wherein the low-density core is made of at least one bee nest, and a metallic or rigid composite material coating envelops the low-density core.
32- Since we can easily obtain high level of concentrations with this new optimized linear Fresnel concentration and collection system. In one of our energy generation systems. We will use latent heat of the see salt to stabilize the boiling temperature of water and help improve the thermodynamic efficiency of this Rankin cycle. One of the storage tanks could be field with see salt. We will pressurize this see salt in a tank and introduce see water in ideal proportions to obtain high pressurized pure steam and harvest the see salt from the bottom of this tank in a liquid state.