WO2018122565A2

WO2018122565A2 - New type solar thermal system

Info

Publication number: WO2018122565A2
Application number: PCT/GR2017/000072
Authority: WO
Inventors: Anastasios VARDAXOGLOU
Original assignee: Vardaxoglou Anastasios
Priority date: 2016-12-30
Filing date: 2017-12-27
Publication date: 2018-07-05
Also published as: WO2018122565A3; GR20160100647A

Abstract

The invention relates to solar thermal systems which include a collector such as a vacuum tube (1) with a heat sink (2) or a Fresnel lens (13) ending up in a focus (14) or a flat collector (11) that by means of mirrors (17) collects the sun rays, or a mirror (18). It also comprises a transfer system which can be an air duct (5), either a water or Freon conduit, or a bellows (15) in which the hot air circulates, or a space enclosed by a blind (21) with a view to transferring the hot air within the space. Storing the excess energy is done with an inertia vessel (8). Alternatively, an electrochromic dyed surface (23) which may be foldable (24), acting as a collector and radiator at the same time, may be used.

Description

DESCRIPTION

"NEW TYPE SOLAR THERMAL SYSTEM"

FIELD OF ART

The invention relates to the field of domestic heating systems and more particularly to room heating systems using liquid and gaseous media. The solar thermal system disclosed herein can be used both as an autonomous heating option and as an aid to existing structures. BACKGROUND OF THE INVENTION

The solar thermal system disclosed in the present invention, with its alternative embodiments, has not been disclosed in the prior art.

Solar thermal systems, using appropriate collectors to capture solar radiation and convert it into heat, have long been used in modern times but have very specific uses. Solar thermal systems consist of a collector, circulation and storage system and most commonly a control system. To date, solar thermal systems have some inherent disadvantages that have not been addressed and resolved effectively. The most significant drawback is their clear dependence on sunshine, the heating energy generation being consequently lower during the period of higher demand, that is, in the winter when we have cloudy and shorter daytime. In addition, due to the limited sunshine, it is often necessary to install a backup energy source to fully meet the needs of a building for the whole year.

A further disadvantage is the fact that some types of solar collectors may have problems in their operation in frosty areas or show significant deterioration due to weather phenomena, thereby increasing the cost of their maintenance. In addition, the solar thermal systems used today require special interventions in every particular installation altering it, while increasing the cost of installing such a system.

Still a disadvantage results from the optical pollution of many of the systems used. This is because their aesthetic impact, compared to other forms of renewable energy, is particularly high, making them undesirable, especially within urban fabric. Last but not least, the low efficiency of systems and the impact of conventional renewable energy technologies on the environment and the high cost of land use must not be ignored.

It is therefore an object of the present invention to advantageously overcome the aforementioned drawbacks and deficiencies of the prior art by proposing a solar thermal system that functions both as a stand-alone heating medium and as an auxiliary means to central heating installations. It is a further object of the present invention to provide a solar thermal system which uses air, water or a suitable gas, such as fluorocarbons, as a heat transfer medium.

It is a further object of the present invention to provide a solar thermal system which uses as a fuel both fossil fuels and electric energy from any form of technology.

It is a further object of the invention to provide a solar thermal system which employs an inertia vessel or any other form of energy storage to utilize the additional heat generated.

It is a further object of the invention to provide a solar thermal system employing a solar collector of any kind or technology, such as a vacuum tube, a flat collector, a parabolic mirror, a Fresnel lens, for heating the water or gas of the thermal body.

Another object of the invention is to provide a solar thermal system which transmits heat through a heat sink which is connected to the heat transfer copper tube through a special adhesive, welding, direct contact by clamping or by any effective way of transmitting heat from the copper tube to the heat sink, or it is initially embedded thereon.

Yet another advantage of the invention is that reduced-section air ducts, which facilitate both installers during application and owners from aesthetic point of view, can be used. Further, the airway may be articulated, consisting of two identical parts, facilitating both its production and its installation.

It is also an object of the present invention to provide a new type of solar thermal system which includes a sun tracking system in order to maximize the exploitation of solar radiation.

It is also an object of the present invention to create a solar thermal system; which by exploiting the electrochromic effect achieves the direct heating of structural elements of a building.

These and other objects, features and advantages of the invention will become apparent in the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become apparent to those skilled in the art with reference to the accompanying drawings, in which it is illustrated in an exemplary, non-limiting manner.

Figures 1 (a) - (b) show in perspective sketches a solar collector with a vacuum tube and a heat sink integrated as part of the tube and a solar collector with an air circulation system, respectively.

Figures 2 (a) - (b) show in a perspective sketch an exemplary embodiment of a solar collector with a vacuum tube and a solar collector with a circulation system ending up in a radiator, respectively. Figure 3 shows a perspective view of a solar collector with a vacuum tube and a closed air circulation circuit.

Figure 4 shows a closed water or suitable gas circulation circuit which ends up in a radiator and has an inertia vessel and a solar collector^' with a vacuum tube.

Figures 5 (a) - (b) show a solar collector with a vacuum tube and closed air and fluorocarbons circulation circuits, which end up in a radiator.

Figure 6 shows a flat solar collector and air circulation system which end up in a radiator.

Figure 7 shows a flat solar collector and a water or fluorocarbons circulation system, connected to an inertia vessel and a radiator.

Figures 8 (a) - (b) show a Fresnel type collector with bellows for space heating, as well as detail of the bellows with the sun's tracking system.

Figures 9 (a) - (b) show a solar air heater with a flat collector and mirrors, moving on a sun tracking system.

Figures 10 (a) - (b) show an alternative inventive embodiment of closed air circulation circuit and a collector on a moving mirror for tracking the course of the sun.

Figure 1 1 shows a detail of the system motion arm for tracking the sun's path. Figure 12 shows a Fresnel type collector with bellows for space heating and a water or fluorocarbon circulation system connected to an inertia tank and a radiator.

Figure 13 shows an alternative embodiment of the invention where a painted exterior wall of an installation is used as a collector, exploiting the electrochromic phenomenon, and an outside enclosure is used as the air circulation system.

Figure 14 also shows an alternative preferred embodiment of the invention, wherein a construction of any form, technology and material suitable for the effective absorption of the incoming radiation developing within the enclosed space acts as flat collector.

Figure 15 shows a further variant of the above embodiment that can be used to assist a heat pump by providing it with air of a temperature much higher than that of the surrounding area resulting in direct maximum efficiency increase.

Figures 16 (a) - (b) show a further variant of the above embodiment, taking advantage of the upper surface of a building, covering it partially or wholly, and the form that such a covering system would have.

Figures 17 (a) - (b) show an alternative embodiment of the invention in the case of tiled roofs. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the accompanying drawings, we will illustrate exemplary embodiments of the new type solar thermal system in order to illustrate its mode of operation and the significant advantages it presents.

Each solar thermal system consists of a collector to convert the solar radiation into heat, a circulation system to transfer the heat generated and usually has control systems and heat storage systems. According to Fig. 1 (a), a vacuum tube (1) is used as collector, where the solar radiation is incident to the tube, is absorbed by it and concentrated at its top. The vacuum tube (1) ends up to a heat sink (2), which is located in a pipe (3), which is cooled by two fans (4). One is located at the inlet of the pipe (3) in order to reduce the system losses, protecting it from the weather, and the other is at the outlet of the pipe, leading the hot air into the space to be heated.. The system results in an air duct (5), Fig. 3, for heating the space. If desired; the air may enter through an ambient air duct (6), Fig. 1(b), which forwards the ambient air. In such a case, a carbon filter and a port mechanism, which closes the inlet of the ambient air duct (6) when it is not in use, is required.

Alternatively, water can be used as heat circulation system, as shown in Fig. 2 (b), wherein the vacuum tube (1) heats water circulating within a copper or aluminium or even steel (7) radiator. The copper radiator (7) may be of smaller dimensions but of the same performance as the conventional radiators, but because of its smaller dimensions it can be placed high in the space so as not to create a visual nuisance. Optionally, a fan (4) can be used to remove the hot air from the heat sink (2). These two features allow for the. maximization of the space available for the people who use the building. The heat sink (2), Fig. 2 (a) can be glued to the copper tube (3) by using special glue, or it can bf rrmyitially incorporated in the tube (3) by casting or by any suitable way.

Alternatively, the inventive device could use an inertia vessel (8), Fig. 4, as storage system of the excess energy for future use. As it is evident, use of an inertia vessel (8) can be realized in the case that water is used as a heat transfer medium or in the case of use of fluorocarbons, known as Freon. It is furthermore clear that if Freon is used, an alternator is required for the operation of the inertia vessel (8).

In a further alternative embodiment of the invention, the collector (1) can heat a copper radiator (7), Fig. 5(b) via the heat sink (2), by induction heating of a closed fluorocarbon circuit. In this case, there are two closed circuits; one with air and the other with Freon. The Freon circuit (9), Fig. 5(a), connected to the radiator (7) for transmitting the heat to the space, is located in a circuit of hot air (10), which heats the Freon circuit (9) by induction. Air circulation can be enhanced by using fans. An alternative embodiment of the new type solar thermal system includes the use of a flat collector (11), Fig. 6, which heats a closed air circuit, which terminates at a radiator (7). The flat collector (11) is placed on the exterior surface of the house and is directly connected to the radiator. Use of a fan (12) inside the space allows for a better transmission of heat to the space. It is to be understood that water or other suitable liquid may again be used in a similar manner as heating medium, Fig 7. In such a case, an inertia tank (8), directly on the radiator (7), can be used to ensure space heating beyond hours of sunshine, too. Similarly, it should be stressed that in case of using Freon as heating medium, an alternator must be used simultaneously.

Iri yet another variation of the invention, a Fresnel type lens (13), Fig. 8(a) can be used as collector. Fresnel lenses are spherical lenses that can focus the light of a source at a point behind the lens, the focus (14). Thus, if an elastic bellows (15) is located on motion rails (16), Fig. 8(b) to follow the course of the sun, the incident beams can end up in the focus (14), heating the air circulating behind the focus (14), producing a flow which will heat a space through an air duct (5). Similarly, with the use of an ambient air duct (6), cold air will be driven out of the space for heating from the system. Correspondingly, the Fresnel lens (13) could heat a water or Freon transfer circuit, Fig. 12, which would end up in a copper radiator (7). Similarly to the former, in the case of Freon use of an alternator would be necessary, while an inertia tank (8) would allow for the further utilization of the hot liquid. An important advantage of the above variant is that with a Fresnel lens, the absorption surface becomes dramatically smaller than with a conventional collector.

A corresponding solar thermal system is shown in Fig. 9(a), wherein the Fresnel lens has been replaced by a flat collector (11) surrounded by mirrors (17), Fig. 9(b) at a suitable angle to concentrate the beams of the sun on the collector (11). Likewise, the movement of the collector-mirror system will be based on the path of the sun through motion rails (16).

Similarly, a mirror (18), Fig. 10(a), which collects the solar radiation in a small piece of flat collector (11) can be used. The mirror (18) collects the solar radiation and emits it to the collector (11), which is encased in a transparent polyacrylic or polycarbonate material (19) to allow the rays to end up thereon. The entire system of the collector (11) with the transparent suitable material (19) is located in a flexible bellows (15) which leads to the inlet and outlet of the air ducts (5), (6) and allows for corresponding movements, as done by the mirror (18), following the course of the sun.

At this point, the functioning of the sun tracking device and its capabilities must be further detailed. The solar tracking system has one or more motion rails (16), Fig. 11 , on which the collector used at the time, being either a Fresnel lens or a mirror, moves. Given that each system is installed at a specific longitude and latitude and knowing the course of the sun for the months of interest, we can suitably place the motion rail (16). The motion rail (16) will include in its slope both the azimuth and the^' elevation change of the sun's position over the months, so that the focus of the system is accurate. The elevation difference within the day will take into account the average of the day. Thus, if for example the difference is from 0 to 50 degrees, the placement will be at 22.5 degrees. When installing the mirror or Fresnel lens, this will be taken into account so that mirroring is always within the collector. The tracking of the sun will be done by moving the collector by means of electric motors, one for each rail or one for all the motion rails (16), which will shift the collector by a predetermined step at similar; intervals. Additionally there will be a height control mechanism (20), with a similarly predetermined motion, minimizing any sun tracking error, without the use of hitherto cost- intensive tracking systems. Finally, alternatively, the rails themselves can have incorporated the height change, ensuring seasonal monitoring by changing the motion rail (16) the corresponding time interval, such as for example one week or one month.

A further variant of the solar thermal system can be done by utilizing the electrochromic effect. An outer foldable transparent blind (21), Fig. 13, of a suitable material, such as polycarbonate, may be placed on an exterior side of a building, for example on a balcony. The blind (21) will seal airtight on a base (22) and will surround the space. The solar radiation will penetrate the blind (21) and it will be trapped inside the space increasing its temperature. The surface (23) on which the light will be incident, for example a wall, shall be dyed with an electrochromic paint. This means that if a small voltage is applied to the surface (23), it will change its colour, being substantially converted to a radiator. The structural element will be both the collector and the radiator. The flow of hot air will take place in parallel with the use of air ducts (5), (6). The electrochromic dye can also be used on indoor walls of the building, increasing the efficiency of the solar radiation entering through the glasses.

In a corresponding alternative embodiment, and if dyeing of a building element is not desirable, it will be possible to use a foldable collector surface (24), Fig. 14, which may have a selective or black dye and which will develop internally of the blind (21), collecting the solar radiation and heating the. entrapped air. Finally, use of the above cases can also be combined with heat pumps, Fig. 15. The hot air trapped by the blind (21) is led to a heat pump (25) and even on cold days the pump operates at the maximum performance factor. Therefore, in the presence of an inertia tank, the radiators could be used for much of the day. An important advantage of the system variants as shown in Figs. 13, 14, 15 is that the electrochromic dye returns to its original colour as soon as it stops flown by current while at the same time both the blind 21 and the collector surface (24 ) are folded, without any permanent visual nuisance resulting from the installation of a permanent collector or from the permanent dark colour of a structural element.

In a further alternative embodiment of the invention, the above- proposed solutions can also be applied to the flat roof of a house, Fig. 16 (a) - (b), where the incident rays of the sun are trapped under the transparent surface (26) heating the insulation of the roof, the latter, as being dyed with electrochromic dye, heating the structural element. It is understood that the complete folding of the surface (26) and the interruption of current application to the dye will visually restore the roof to its original state.

Finally, in the case of tile roofs, Fig. 17 (a) - (b), the tiles can be removed and in their place a translucent polycarbonate frame may be placed, which will be like the blinds of a balcony door, having an outer and an inner part. The inner part will tie and close the existing insulation, while the outer one will create the greenhouse effect. In the meantime, there will be a suspended solar absorber (27) intended to absorb the solar energy for the most part. The vacuum in which the absorber will be housed will communicate with an air duct (5) and an ambient air duct (6) so that heat can be transferred directly to the desired space. The system may be supplemented with ventilation ports for the excess heat and to avoid moisture within the housed space.

It is to be noted here that the description of the invention has been made by reference to exemplary, but not limited to, embodiments. It is clear that any change or modification in terms of shape, dimensions, materials and components of manufacture and assembly, provided that they are not a novel inventive step and do not contribute to the technical development of the already known one, are considered to be within the scope and purpose of present invention.

Claims

1. A new type solar thermal system, comprising a light collector and a circulation system for transferring the heat generated, characterized in that the collector is a vacuum tube (1) which terminates at a heat sink (2) in a tube (3) being the circulation system (4) with a fan to extract air and an air duct (5) for heating the space.

2. A new type solar thermal system according to claim 1 , characterized in that either a Fresnel lens (13) ending up in a focus (14) or a flat collector (1 1) surrounded by mirrors (17) at an angle, or a mirror (18) emitting radiation into a collector embedded in a transparent polycarbonate material (19), or an electrochromic dyed surface (23), or a foldable, dyed collector surface (24), developed in a blind (21) airtight sealing a space, are used as light collector.

3. A new type solar thermal system according to claim 1 , characterized in that a water conduit terminating at a radiator (7) and an inertia vessel (8), or a Freon conduit, or a closed Freon circuit (9) heated by induction by an air circuit (10) in which there is either an elastic bellows (15) on motion rails (16) in which the hot air circulates or a space airtight enclosed by a blind (21) where the hot air is trapped, are used as circulation system.