WO2011010173A2

WO2011010173A2 - Three wall vacuum tube solar collector located in the focus of a non moving semicylindrical parabolic reflector used for production of steam to get electric and thermal energy

Info

Publication number: WO2011010173A2
Application number: PCT/GR2010/000032
Authority: WO
Inventors: Dimos Maglaras
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-07-24
Filing date: 2010-07-23
Publication date: 2011-01-27
Anticipated expiration: 2012-01-24
Also published as: WO2011010173A3; GR20090100414A

Abstract

Three wall solar vacuum collector (1) (closed circuit) located in the focus of a non moving semi-cylindrical reflector (15) and regarding the use, connection of 5 or 6 or 7 solar collectors (1 ) in series the number of the collectors connected in series is a function of the pressure and the temperature of the steam that is produced for the steam-turbine (2), that is employed in junction with a electric-generator (23) to produce electric energy (34), using the condenser (25) of the steam-turbine (2) the steam is liquidated by circulating cold water or special oil, in closed circuit (27) this way we also obtain thermal energy (23). The liquidized steam-water is driven via a steam-trap (28) in a tank for the liquidized steam-water (19) and from there using a high pressure pump the liquidized steam-water (29) is inserted in the series of the solar collectors (1) to be vaporized again. The filling level (13) is retained employing an appropriate automation system (17) in the steam-boilers, while the water needed to replace the water (or steam) that could escape is done automatically in the steam-water tank via a water- softener (31). The silicon used for sealing (4) the edges of the glass-tube (9), that contains the iron- tube (3) as a third wall, and the vacuum (33) can withstand high temperatures of 300°C or even 400°C, while the tubes (3) are made of iron-tubes or seamless tubes or stainless steel pipes, and both the inner tube (6) and the outer tube(3) are sealed and can bear pressure of 20 bar or even 60 bar. Further more, they have a big diameter so that the focal points of the sun rays are concentrated throughout the whole day on the selective surface (32) off the outer tube (3) without moving the reflector (15). The rings of the inner tube (3) are half filled with water in order to facilitate the vaporization and the vacuum tubes(1) are interconnected via pairs of small tubes over and under each bottom (8) allowing the water circulate in the bottom (10) and allowing the steam at the top (14) to pass from tube (1) to tube (1) of each series of collectors.

Description

TITLE : THREE WALL VACUUM TUBE SOLAR COLLECTOR LOCATED

IN THE FOCUS OF A NON MOVING SEMICYLINDRICAL PARABOLIC REFLECTOR

USED FOR PRODUCTION OF STEAM TO GET ELECTRIC AND THERMAL

ENERGY.

DESCRIPTION :

Tree wall vacuum tube solar collector (1) that consists of an external glass-tube(9) that encloses and is run coaxially throughout it by a tube (3) made of iron tube or seamless tube or stainless steel pipe of relatively big diameter (due to the big diameter, all the focal points off the sun rays are concentrated throughout the day on the lateral selective surface of the external iron-pipe (3) without having to move the semi-cylindrical parabolic reflector, in the focus of which the vacuum tube (1) is placed and has closed ends with concave bottoms (8) in order to withstand high pressure of 20 or even 60 bar and its length reasonable so as to have a handy product. The edges of the glass-tube

(9) are sealed employing special silicone that holds the vacuum (33) in high operating temperatures from 300⁰C to 400⁰C. Inside it another tube(6) is located (6) coaxially, this is also a tube (3) made of iron pipe or seamless pipe or stainless steel pipe of a smaller diameter of 1,5cm to 2 cm and this pipe has also closed edges and can bear 20bar or 60bar and it is about 10 cm shorter in length (this way the capacity of the external tube is limited to a tubular ring of water (7) that is thick about 1cm and has a volume of a few liters, the water is circulating in a closed circuit) The external iron-tube (3) has a part of it that is inside the glass-tube (9) and this part is wrapped in a selective surface (32) sealed in high vacuum (33) up to 10^~5 BAR inside the glass-tube (9) that surrounds the iron-tube (3) and consists the 3^rd wall.

The edges of the iron-tube (3) that are located from both sides outside the glass- tube(9), are insulated properly eg. employing rock-wool 3cm in thickness at least and this is surrounded by a shell(12) eg made of aluminum and the insulation is tightly incorporated in the shell(12) and the glass-tube(9) but this does not commit the invention. This way the transportation of the tubes (1) til the installation and also the fixation of the collectors on the special metallic structure used to place them is facilitated. Figure 1 depicts the solar collector and figure 2 depicts the way of using them to produce steam and electric and thermal energy.

In both sides of the bottoms(8) there are two tubes (seamless tubes) in the lower part

(10) and through it the water that is contained in the series of 5 or 6 or 7 collectors(1) circulates from collector(1) to collector(1) and from tube to tube, and one in the upper part(14) of the of the bottom and through it the steam circulates from collector(1) to collector(1). Through the lower tube(10) of the last or the first collector(1) of a series of collectors (pilot) (16) the level of the water(13) in the collectors will be regulated. The collectors (1) will be about half filled with water.

The collectors (1) will be positioned horizontally and in the same level throughout every series. The solar collectors(1) will be used in series that contains an adequate number of collectors(1) in order to produce the required quantity of super hot steam, measured in kg/h , so as to produce electric energy via an electric generator. The level will be hold employing an appropriate automation system(17) that will be used in the steam-boilers, and this automation system will control the pump(18) for the steam-water(29) that will be described later on (used to close the cycle of continuous operation). Furthermore, when the systems starts to operate, if needed, when the sunlight begins or after a stop , automatically a layer of pressurized air (22) will be supplied in the upper part of the tubes via an auxiliary air compressor unit (20) so as to obtain the wanted pressure level for the electric generator to operate and for the system to produce steam. The pressure level will be hold by a steam valve(21) so as to let the air pass through when the system starts up and also discharge the pressure when the system overheats and the pressure in the system is tends to increase.

The steam-turbine (2), connected properly to an electric generator (23) will produce AC or DC electric energy (34) depending on (this is not a reason of a new invention) the generator(23) or the turbines(2) or on any other mechanism that employs rotating axis eg piston reciprocating (Stirling engine). The steam-turbine (2) will be followed by a condenser(25) and inside the condenser chilled water or oil(special) will circulate in closed circuit(26) and those will be heated and used for industrial or other uses of any type such as heating or air conditioning when employing also an absorption chiller etc. The condenser will condensate the steam to liquid and exploiting also the latent heat will provide sufficient thermal energy(27) to the closed circuit of the water or the oil. The liquidized stream will through a steam trap (28) either by natural flow or by forced circulation will be guided inside an insulated steam-water tank (19) where the temperature could be about 90 oC. A special pressure pump(18) will drive the water from the steam-water tank (19) inside the system of the solar collectors (1) connected in parallel utilizing an automation system installed in a series of collectors that has been chosen as a pilot(16) and will stimulate the automation system. The level of the steam- water tanks is retained using a float valve(30) and a quantity of purified water(31) used to replace the losses. This way a continuous procedure of steam and electricity production is created as already has been stated before.

Variations of this invention exist regarding (our European patent No 1072507/2 JAN.04 for using hot water of 6O⁰C or 8O⁰C or 9O⁰C or 95⁰C, in closed or open circuit of interconnected solar collectors that can hold the vacuum til 12O⁰C) either the arrangement or the way of interconnection to produce super hot steam of pressure that the steam-turbine (2) requires or the cost that is not elevated by using expensive servomechanisms that other technologies require in order to obtain precise focusing of moving reflectors. This way electric energy(34) and thermal energy are produced(27) (during the liquidation of the steam) all year round and the amortization period of this system is about five or six years only ! The expected revenue itself is an important reason by itself to approve the patent.

Claims

1. Three wall vacuum tube solar collector(1) located in the focus of a non moving semi-cylindrical reflector(15) that produces steam used to get electric and thermal energy that is characterized by that each vacuum tube(1) consists off an external glass-tube(9) that encloses and is co-axially run through by, a metallic tube(3) made off iron-tube or seamless tube or stainless steel pipe of relatively big diameter (so as to achieve that all the focal points of the reflector are concentrated throughout the day on the lateral cylindrical surface, without having to move) and has both ends closed with concave bottoms (8) so as to be able to withstand high pressure of 20 bar or even 60 bar and its length is practically exploitable. The ends of the glass-tube(9) are sealed(4) using special silicone that holds the vacuum (33) in high operating temperatures from 300⁰C to 400⁰C (without constraining the invention). Inside it another metallic tube(6) is placed (6) coaxially, this is also an iron pipe or a seamless pipe or a stainless steel pipe of a smaller diameter, about 1 ,5cm to 2 cm and this pipe is also closed at both ends of it and can bear 20bar or 60bar and it is about 10 cm shorter in length than the external(3) so as to limit the capacity of the external tube(3) to a tubular ring of water(7) that is thick about 1 cm and has a volume of a few liters ( the water is circulating in a closed circuit ). The part of the external iron-tube(3) that is inside the glass-tube(9) is wrapped in a selective surface(32) eg in a selective surface of black titanium and is sealed in high vacuum(33) of 10-5 BAR inside the glass- tube^) that consists the 3^rd wall. The edges of the iron-tube(3) that are located from both sides outside the glass-tube(9), are insulated employing rock-wool(11) and other materials and is surrounded by a metallic or plastic shell(12), the iron- tube^) is tightly joined to the shell(12) and to the glass-tube(9). Any other way of insulating or steady fixing the shell(12) could not result to a new invention. In each bottom(2) in both ends of each collector(1) there are located two pipes (seamless pipes ), one pipe is located in the lower part (10) and through it circulates from collector(1) to collector(1) and from vacuum tube(1) to vacuum tube(1) water that is contained in a series of collectors and will be vaporized, (the number of collectors (1) depends on the required quantity of steam). The collectors(1) will be half filled with water and the level(13) of water contained in the collectors is regulated through the lower tube(10).The other tube is located in the upper part(14) of each bottom (12) and through it steam circulates from collector(1) to collector(1) when the collectors are used to produce steam and electric energy.

2. Three wall vacuum tube solar collector(1) located in the focus of a non moving reflector(15) that produces steam used to get electric and thermal energy as claim 1 that is further characterized by that instead of having two tubes (10) (14) connecting collector(1) to collector(1) a single pipe of greater diameter is used in the lower part to connect collector(1) to collector(1) allowing the water to circulate through the lower part of this tube and the steam through the upper part of this greater tube.

3. Three wall vacuum tube solar collector(1) located in the focus of a non moving semi-cylindrical reflectory 5) that produces steam used to get electric and thermal energy as claim 1 and 2 further characterized by that regarding the use of the vacuum tubes (1) one of the parallel series of solar collectors(1) is chosen as a pilot(16) and using a proper automation system(17) that is also used in steam-boilers, the quantity ant the level (13) of the water is used for vaporization is hold constant inside the series of the collectors. The automation system(17) triggers a pump that operates in pressure higher than the pressure of the system of the collectors(1) so as to achieve feeding the system with steam-water that is concentrated in an insulated tank or reservoir(19).

4. Three wall vacuum tube solar collector(1) located in the focus of a non moving semi-cylindrical reflectory 5) that produces steam used to get electric and thermal energy as claim 1 to 3 further characterized by that regarding the use the axis of the steam-turbine(2) is connected to an axis of an AC or DC electric generator via a gear box (24) to produce electric energy using solar energy. The type of the generator or the mode of connection the electric generator(23) does not imply a new invention. Further more using instead of a steam-turbine any other device that results in spinning an axis(eg reciprocating pistons, Stirling engine ) that connects to an electric generator(23) does not also imply an new invention. The steam-turbine (2) will be followed by a condenser(25) where the discharged steam is collected. Inside the condenser chilled water or special oil will circulates in closed circuit(26) and liquidates the steam getting thermal energy(27). Employing steam traps (28) and either by natural flow or by forced circulation the steam-water is driven inside the insulated steam-water tank (19) where a pump(18) and an automation system(17) will drive back the water from the steam-water tank (19) inside the series of the solar collectors (1) connected in parallel, refilling them and ensuring continuous system operation (closed circuit). Any leakages of steam or water are replaced in the tank (19) of steam- water via a float valve(30) (ballcock)automation that adds cold water or via a water purification (31) like the ones used in steam-boilers, the use or not of such a system does not imply a new invention.

5. Three wall vacuum tube solar collector(1) located in the focus of a non moving semi-cylindrical reflectory 5) that produces steam used to get electric and thermal energy as claim 1 to 4 further characterized by that regarding the use the solar collectors will be fixed in groups in a way that it will allow easily to alter the elevation angle of a group of collectors every winter, spring, autumn and summer, depending on the latitude of the location where the collectors(1) are installed.