Solar radiation modular collector

Abstract

The invention relates to the field of solar radiation collectors intended to convert energy of solar radiation into thermal energy, specifically, to the solar radiation collectors constructed as the combination of a concentrated solar radiation receiver, a single-curvature or compound-curvature concentrator and a tracking mechanism. A thermal insulation of the concentrated solar radiation receiver and the concentrated solar radiation receiver itself play a role of parts in the tracking mechanism.

Description

FIELD OF THE INVENTION

The present invention relates to the field of solar radiation collectors intended to convert energy of solar radiation into thermal energy.

BACKGROUND OF THE INVENTION

Solar radiation collectors which convert energy of solar radiation into thermal energy are known. Some types of such collectors include those which incorporate single-curvature or compound-curvature concentrators.

If single-curvature parabolic mirrors are used as the concentrators, the modular solar radiation collector is constructed as a combination of an elongated receiver, the single-curvature concentrator and a tracking mechanism, which ensures steady positioning of the elongated receiver in the focal zone of the single-curvature concentrator.

It is known that such solar collectors can result in temperatures of a working fluid which are significantly higher than 100° C.; this in turn gives the possibility of applying the obtained thermal energy to different industrial processes or to convert this thermal energy into electricity with sufficiently high efficiency. In the most cases, the single-curvature concentrator is constructed as a trough-wise parabolic mirror or a single-curvature Fresnel lens.

The elongated receiver is usually constructed as a pipe with an outer coating intended to absorb concentrated and direct solar radiation, and a transparent (glass) elongated envelope positioned around the pipe. The transparent envelope is sealed with the pipe at its ends and the gap between the pipe and the elongated envelope is vacuum-insulated in order to suppress convective losses of thermal energy from the outer surface of the pipe.

There are some drawbacks of this construction, a few of which are listed below.

1. Concentrated solar radiation illuminates only a part of the whole surface of the radiation receiving pipe; at the same time, heat loss by radiation occurs from the entire outer surface of this pipe.

2. Sealing the metal pipe of the receiver with the glass envelope is very expensive and complicated from the technological point of view.

3. It is impossible to insulate thermally the radiation receiving pipe in a modular manner.

4. Low strength of the glass envelope does not permit this glass envelope to be used as a carrying element of the construction of a solar collector.

These same drawbacks are also true for solar collectors which feature compound-curvature dish-type concentrators.

There are some US patents related to the area of this invention, none of which completely solve the above problems. U.S. Pat. No. 4,078,549 to McKeen describes a solar energy collector which concentrates the sun's rays on a liquid medium that is used to power a mechanical energy device such as a positive displacement steam engine. A reflective surface of the solar energy collector is made from an arcuate portion of a circle having a trough-like surface to reflect and concentrate the sun's rays in a plane. A collector having a liquid medium flowing therethrough is located in the plane. The collector is constructed to extend across the entire plane for complete absorption by the liquid medium of the sun's rays reflected from the reflective surface. The collector and reflective surface are connected together for pivotal movement by an appropriate tracking apparatus so that the sun's rays are continually reflected during normal daylight hours through the plane in which the collector is located.

However, this patent has numerous drawbacks, a few of which are listed below It does prevent heat loss from the receiving pipe due to infrared radiation.

It does not permit enclosure of the majority of the receiving pipe by the thermo-insulating envelope (in fact, the thermo-insulating envelope encloses less than 50% of the surface of the receiving pipe).

It does not permit the internal reflecting surface of the envelope to be used as a secondary non-imaging concentrator.

U.S. Pat. No. 4,048,982 to Pei describes a bulb-type solar energy collector comprising a hollow glass body shaped with a parabolic interior surface that is coated with specular finish of a metal, e.g. silver, and includes an apex aperture and integral hollow yoke. A hollow glass, bulb-shaped absorber element is exteriorly coated with a wave length selective coating. The bulb-shaped element includes a tubular hollow stem dependent from the bulbar portion and fixed in the yoke of the glass body so that the central axis of the stem and bulbar end portion is along the focal axis of the parabolic reflecting surface. A cover plate is sealed over the enlarged end of the reflecting surface enclosing the interior mirror surface in a chamber which is evacuated to substantial vacuum, e.g. 10⁻⁴ torr or greater vacuum. A working liquid is circulated from a source in a manifold through the interior volume of the absorber element to remove the solar energy absorbed thereby as heat and the media is returned to the manifold. The solar energy laden liquid is available for heating, cooling or power generating uses.

Pei does not teach any technical solution of tracking the reflector after the sun motion.

BRIEF SUMMARY OF THE INVENTION

The background art does not teach or suggest a solar collector device for both providing sufficient insulation of a solar radiation receiver so as to decrease significantly or prevent heat loss (thereby increasing efficiency of collection of solar energy) and also for most efficiently tracking the sun in order to obtain the most efficient amount of solar exposure.

The present invention overcomes these deficiencies of the background art by providing (in a first embodiment) a solar radiation modular collector with a concentrating unit of the single-curvature type (one-axis sun tracking concentrator) and with a receiver of concentrated solar radiation in the form of a radiation receiving pipe.

The radiation receiving pipe is provided with a thermal insulation layer which is preferably in the form of a metal envelope, which may optionally be vacuum-insulated and/or filled with material with low thermal conductivity. In addition, the internal cavity of this metal envelope may optionally feature one or more radiant shields from metal foil with high reflection coefficient in the infrared range. The single-curvature concentrator can optionally be constructed as a parabolic trough-wise reflector, or alternatively as a single-curvature Fresnel mirror.

The metal envelope insulates most of the outer surface of the radiation receiving pipe with significant reduction of heat losses caused by convection and radiation from this part of the outer surface.

The metal envelope of the radiation receiving pipe is preferably constructed from two elongated internal and external sections, which are joined by two elongated connection straps and sealed at their ends by face planes.

The internal elongated section comprises a cylindrical sub-section, which encloses a significant part of the radiation receiving pipe; this cylindrical sub-section is transformed at its longitudinal margins to flat or single-curved strips with a certain angle of convergence with respect to the cylindrical sub-section. In such a way, the cross-section of the internal section is somewhat similar to the vertical cross-section of a jug. The external section encloses the internal one.

The internal cavity between the internal and external sections of the metal envelope is preferably evacuated (to form a vacuum) in order to suppress convective loss of heat. In addition, this space can be filled with a porous material and/or layers of metal foil in order to diminish heat loss by radiation.

It is possible to apply filling the internal cavity of the metal envelope with a gas having low thermal conductivity, for example, krypton.

The gap between the elongated connection straps is preferably glazed in order to diminish heat losses, which occur from the part of the radiation receiving pipe that is not enclosed by the cylindrical sub-section of the internal elongated section.

According to preferred embodiments, a plurality of metal envelopes may optionally be installed sequentially around a radiation receiving pipe in place of a single envelope. Each such envelope is preferably constructed as described previously. This simplifies the manufacturing process of the metal envelopes.

Without wishing to be limited by a single hypothesis, thermal losses in the proposed construction of the thermal insulation may be expected to occur one of three ways:

By thermal conductivity of the walls of the metal envelope.

By radiation from the illuminated surface of the radiation receiving pipe.

By convection via the internal cavity between the internal flat strips, the glazing and the radiation receiving pipe.

By way of example only and without wishing to be limited in any way, the above problems may optionally be solved as follows. The optional but preferred glazing of the internal cavity between the internal flat strips significantly reduces thermal losses occurring by convection. In addition, the glazing may optionally be provided with a transparent coating, which reflects back infrared radiation from the radiation receiving pipe.

The limited thermal conductivity of the walls of the metal envelope may cause temperature gradient to occur within the envelope and in turn this can cause deformation of the metal envelope.

In order to prevent this, the internal and external sections of the metal envelope are optionally and preferably provided with corrugations, which decrease in dimension to zero (ie are narrowed) in the vicinity of the connection straps. These corrugations can be directed inwards or outwards with respect to the internal cavity of the metal envelope.

The outer surface of the external section of the metal envelope can be coated with a coating, for example by being painted with black paint or pigment, and/or with paint or pigment having a very low emittance coefficient in the infrared range; it enables the temperature of the external section of the metal envelope to be raised due to the direct solar radiation falling on its surface. It in turn diminishes heat losses caused by thermal conductivity of the metal envelope and by radiation and thermal conductivity through the internal cavity of the metal envelope.

The proposed receiver of the solar radiation may optionally be rigidly joined by a set of truss struts with the single-curvature concentrator, which should be rotated by a tracking mechanism in accordance with the sun motion. In this case, the receiver rotates by turning the single-curvature concentrator.

According to some embodiments of the present invention, the mechanical strength of the metal envelope also optionally and preferably enables the modular solar collector to feature a stationary metal radiation receiving pipe. In this case, the metal envelope with the single-curvature concentrator is rigidly joined to the metal envelope by the truss struts and is rotated around the metal radiation receiving pipe by the tracking mechanism. In such a way, the radiation receiving pipe plays the role of a bearing element and an axle.

The radiation receiving pipe may optionally be provided in this case with a set of ribs in order to prevent contact of the internal surface of the metal envelope with the black or selective coating of the radiation receiving pipe. In addition, the cylindrical surface of these ribs may optionally be provided with an antifriction coating.

The proposed construction of the thermal insulation of the radiation receiving pipe allows the solar radiation collector to be assembled in a modular manner without requiring complicated and expensive sealing means between a glass cylindrical envelope and the radiation receiving pipe, as is known in the art.

According to other preferred embodiments of the present invention, a plurality of solar radiation modular collectors may optionally be located in parallel rows and provided with common tracking mechanisms.

According to another embodiment of the solar collector according to the present invention, compound-curvature concentrators and, particularly, dish-type parabolic mirrors, are used as the concentrators of solar radiation.

If the compound-curvature concentrators are in the form of the dish-type mirrors, a module of the present invention preferably features a bearing pipe that is mounted on vertical posts. A heat transfer medium (working fluid) flows in the bearing pipe. The bearing pipe is provided with a layer of thermal insulation.

A plurality of T-pieces are built into the bearing pipe, i.e. the bearing pipe comprises a set of tubular sections with T-pieces installed between two neighboring tubular sections to connect them. The lower branch of each T-piece is sealed by a metal convex spherical cap and at least a portion of the outer surface of the T-piece is covered with a layer of thermal insulation.

In addition, there is a solar radiation receiving member, which is constructed from a dish-type plate and a double-wall funnel. The upper side of the dish-type plate has the concave surface in the form of a spherical segment with the radius almost identical to that of the metal convex spherical cap. In such a way, the pair of the spherical cap of the T-piece and the concave surface of the dish-type plate together presents a spherical joint. The lower surface of the dish-type plate is preferably covered with a layer of a solar radiation absorption coating.

The upper surface of the dish-type plate and the outer surface of the metal convex spherical cap may optionally be provided with antifriction coating.

The upper edge of the internal wall of the double-wall funnel is joined with the edge of the dish-type plate and the edge of its outer wall is provided with a flange.

The distal (lower) aperture of the double-wall funnel can be glazed in order to diminish heat losses via its internal cavity. In addition, this glazing can be provided with a transparent coating, which reflects back infrared radiation from the layer of the solar radiation absorption coating of the dish-type plate.

The internal surface of the internal wall of the double-wall funnel is preferably constructed of one or more materials with the property of high reflectivity for solar radiation; in such a way, this internal wall plays a role of an additional non-imaging concentrator of the solar radiation.

There is a bearing housing with a split lower flange and two longitudinal slots; this housing is mounted on the thermal insulation of the T-piece. The open sections of the longitudinal slots are closed by a clamp. The flanges of the bearing housing and the outer wall of the double-wall funnel are joined by a flexible joint, which plays at the same time a role of a thermal insulator.

The outer wall of the double-wall funnel serves at the same time for mounting truss struts, which serve in turn for installation of a dish-type concentrating mirror with its frame.

The frame of the dish-type mirror is joined through cylindrical hinges with tracking rods.

The internal cavity between the walls of the double-wall funnel and between the flexible joint and the lower branch of the T-piece may optionally be filled with thermo-insulating material with low thermal conductivity.

It should be noted that heat transfer from the internal surface of the spherical cap to the working medium is performed mainly by natural convection, conduction and boiling. In order to diminish temperature drop between this internal surface and the working medium, the internal surface of the spherical cap may be provided with fins and/or a porous coating from metal powder; this porous coating has open porosity.

It is possible to use a funnel with a single wall instead of the aforementioned double-wall funnel; in this case the lower edge of the funnel is joined with a connecting branch with a flange; this connecting branch is joined in turn with the lower flange of the flexible joint. The truss struts are joined in this case with the connecting branch.

In addition, it is possible to obviate use of the dish-type plate. The outer surface of the metal convex spherical cap is provided in this embodiment with a radiation absorption coating. This coating is preferably stable against friction with the upper edge of the aforementioned double- or single-wall funnel.

A solar radiation collector may optionally be assembled from a plurality of solar radiation modular collectors, which are described above; this plurality of solar radiation modular collectors is preferably placed in the form of parallel rows and bearing pipes are interconnected in series in each row.

Solar radiation modular collectors, which are positioned in parallel and/or belong to one set of interconnected serial bearing pipes, preferably have common tracking units.

Without wishing to be limited to a single set of advantages, it should be noted that the technical solutions described above have a number of advantages, a few of which are listed below.

In the first described embodiment of the proposed solar collector with a trough-wise concentrator, the metal thermal insulation of the receiver has a number of functions, which are not known in the background art:

It serves as an non-imaging concentrator;

Its corrugations prevent its thermal deformation and serve as elements of the tracking mechanism;

It is supporting the concentrators.

This is true as well regarding the receiver, which also has some additional functions:

It is a bearing element for the thermal insulation and for the concentrators;

It is an element in a tracking mechanism.

In the second embodiment of the invention with a dish-wise concentrator, T-pieces with their caps of the bearing pipe also have a variety of functions:

1. They are bearing elements for double-wall funnels and the concentrators;

2. They serve for heat transfer to a medium flowing in the bearing pipes;

3. They serve as elements in the tracking mechanism.

On the other hand, the double-wall funnels with their dish-type plates also have additional functions:

Their dish-type plates serve for heat transfer to the spherical caps of the T-pieces;

The double-wall funnels serves as non-imaging concentrators;

The double-wall funnels with their dish-type plates are elements in the tracking mechanism;

The double-wall funnels are the bearing elements for the dish-type concentrators.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a transverse cross-section of a receiver of a concentrated solar radiation collector module with a concentrating single-curvature unit.

FIG. 1 b is an exploded transverse cross-section of the metal envelope of the receiver and its glazing.

FIG. 1 c is an exploded transverse cross-section of a radiation receiving pipe of the receiver.

FIG. 2 is an isometric view of an internal section of a metal envelope of the receiver, which is shown in FIG. 1a and FIG. 1b, with corrugations directed inwards.

FIG. 3 is an isometric view of an external section of the metal envelope of the receiver, which is shown in FIG. 1a and FIG. 1b, with corrugations directed outwards.

FIG. 4 is an axial cross-section of the radiation receiving pipe of the receiver, which is shown in FIG. 1a and FIG. 1c.

FIG. 5 is a transverse cross-section of the solar radiation collector modules for concentrating single-curvature units and with some elements of a tracking mechanism.

FIG. 6 demonstrates an isometric view of the section of the receiver of concentrated solar radiation for the case of application a concentrating single-curvature mirrors.

FIG. 7 is a cross-section of a combined unit: a T-piece—solar radiation receiver with application of a double-wall funnel and a dish-type radiation absorption plate.

FIG. 8 is a cross-section of a combined unit: a T-piece—solar radiation receiver with application of a single-wall funnel and a dish-type radiation absorption plate.

FIG. 9 is a cross-section of a combined unit: a T-piece—solar radiation receiver with application of a metal convex spherical cap for absorption of concentrated solar radiation.

FIG. 10 is a longitudinal cross-section of the solar radiation collector module with a concentrating compound-curvature unit and with some elements of a tracking mechanism.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 a, FIG. 1b and FIG. 1c show the transverse cross-sections of the receiver of concentrated solar radiation for the embodiment of the present invention featuring a concentrating single-curvature unit. The figures show an exploded transverse cross-section of the metal envelope of the receiver and its glazing and an exploded transverse cross-section of a radiation receiving pipe of the receiver.

This embodiment of the device according to the present invention includes a radiation receiving pipe 101 with a selective coating 102 of its outer surface and low circular ribs 103, and a metal envelope 104. Preferably coating 102 is made of selective coating material (preferably absorbing strongly in the visible range but only weakly emitting in the infra-red range of light). As previously described, radiation receiving pipe 101 receives radiation and is insulated by metal envelope 104.

Metal envelope 104 includes an internal elongated section 105 and an external elongated section 106, which are joined by two elongated connection straps 107 and sealed at their ends by face planes; the internal elongated section 105 comprises in turn a cylindrical sub-section 108, which encloses a significant part of the radiation receiving pipe 101 for insulating it from heat loss. Cylindrical sub-section 108 features at its longitudinal margins a plurality of flat strips 109 with a defined angle of convergence with respect to the cylindrical sub-section 108.

The external elongated section 106 comprises a cylindrical sub-section 110, which encloses the cylindrical sub-section 108; cylindrical sub-section 110 features at its longitudinal margins a plurality of flat strips 111 with the same angle of convergence as for flat strips 109. The angle of convergence preferably enables additional radiation reflected from the surface of the flat strips 109 to be collected by the radiation receiving pipe 101 and also for heat to be maintained in the area of the radiation receiving pipe 101, further increasing the efficiency of energy collection.

Two elongated connection straps 112 join the flat strips 109 and flat strips 111.

The internal space between the internal and external sections (108 and 110, respectively) is preferably evacuated in order to reduce convective losses of heat. In addition, this space may optionally be filled with a porous filler 113 to further reduce heat loss.

In addition, radiation shields in the form of metal foils 114 are situated in the internal cavity of the metal envelope 104 to reduce heat loss and to increase the efficiency of energy collection.

The flat strips 109 are provided with longitudinal clamps 115, which serve for fastening glazing 116. Glazing 116 preferably increases the efficiency of energy collection and also reduces radiant and convective heat loss.

FIG.2 shows an isometric view of the internal section of the metal envelope alone according to an optional embodiment with corrugations directed inwards.

It comprises a cylindrical sub-section 201, which features flat strips 202 at the longitudinal margin as previously described.

The cylindrical sub-section 201 and the flat strips 202 are preferably provided with corrugations 203, which decrease in dimension at their lower margins. These corrugations 203 are preferably directed inwards with respect to the cylindrical sub-section 201. The lower edges of the flat strips 202 are provided with elongated connection straps 204. Dimensions of corrugations 203 are a function of the mechanical properties of the envelope (material and dimensions) and also depends on the temperature differential. Corrugations 203 preferably are constructed so as to prevent distortion due to a temperature gradient on the metal envelope and mechanical stresses caused by this temperature gradient, as previously described.

FIG. 3 is an isometric view of an external section of the metal envelope alone according to an embodiment featuring corrugations directed outwards.

It comprises a cylindrical sub-section 301, which also features flat strips 302 as previously described.

The cylindrical sub-section 301 and the flat strips 302 are preferably provided with corrugations 303, which decrease in dimension at their lower margins. Corrugations 303 are directed outwards with respect to the cylindrical sub-section 301.

FIG. 4 shows an axial cross-section of an embodiment of the radiation receiving pipe alone. It comprises a metal pipe 401 that is provided with two bellows 402 at its extreme sections. Bellows 402 are intended to compensate thermal expansion of the metal pipe 401. The outer surface of the metal pipe 401 is provided with a selective coating 403 which preferentially absorbs solar radiation and has a low emittance of infra-red energy. Selective coating 403 may optionally cover only the part of the outer surface of pipe 401, which is irradiated by the concentrated solar radiation. In addition, the metal pipe 401 is preferably provided with low ribs 404, which prevent immediate contact of the selective coating 403 with the surface of the internal section of the metal envelope (not shown) when the envelope rotates around the metal pipe 401. The cylindrical surfaces of the low ribs are preferably coated separately with antifriction coating 405 also to prevent friction during rotation.

Flanges 406 are installed on the ends of the metal pipe 401.

Bellows 402 may optionally be made of the same material as metal pipe 401; the material is preferably selected according to the dimensions of bellows 402 and the plasticity of the material.

FIG. 5 is a transverse cross-section of two solar radiation collectors positioned in parallel with a common tracking rod and with a concentrating single-curvature unit.

It shows posts 501 with pipes 502 installed on their upper sections. A metal envelope 503, which is provided with glazing 504, is situated on pipe 502 and can rotate around pipe 502. Truss struts 505 serve for fastening frames 506, which in turn serve for installation of parabolic trough-wise mirrors 507. A common tracking rod 508 is joined by hinged units 509 with frames 506. This enables the unit to follow the motion of the sun through movement by a common tracking unit (not shown; may optionally employ a motor to power movement of the unit). Pipes 502, metal envelope 503 and glazing 504 preferably operate together are as for FIG. 1. Metal envelope 503 also collects energy through heating due to some radiation falling onto it. Glazing 504 preferably diminishes heat loss through natural convection.

FIG. 6 demonstrates an isometric view of the section of the receiver of concentrated solar radiation for the embodiment featuring a single-curvature concentrating mirror.

It comprises: a radiation receiving pipe 601 with a selective coating, and a metal envelope that includes an internal elongated section 602 and an external elongated section 603. These sections 602 and 603 are joined together to elongated connection straps 604. The internal elongated section 602 comprises, in turn, a cylindrical sub-section 605, which encloses a majority of the radiation receiving pipe 601; this cylindrical sub-section 605 is transformed at its longitudinal margins to flat strips 606 with a certain angle of convergence with respect to the cylindrical sub-section 605.

The external elongated section 607 comprises a cylindrical sub-section 608; this cylindrical sub-section 608 is transformed at its longitudinal margins to flat strips 609 with the same angle of convergence as the flat strips 606.

The internal space between the internal and external sections (sections 602 and 603 respectively) is preferably evacuated in order to reduce convective losses of heat.

The flat strips 609 are provided with clamps 600, which serve for installation of glazing 611.

The cylindrical sub-section 605 and the flat strips 606 are provided with corrugations 612, which decrease in dimension at their lower margins. These corrugations 612 are directed inwards with respect to the internal elongated section 602.

Truss struts 613 are installed on the outer surface of the flat strip 609.

The function of these elements is similar to that of the corresponding elements of FIGS. 1-5.

FIG. 7 demonstrates a cross-section of a combined unit (which is another embodiment according to the present invention), featuring a T-piece—solar radiation receiver with a double-wall funnel and a dish-type radiation absorption plate.

It comprises: bearing pipes 701 and 702 with insulting layers 703 and 704, and a T-piece 705 with an insulating layer 706. The lower branch of this T-piece 705 is sealed by a metal convex spherical cap 707. In addition, there is a solar radiation receiving member, which is constructed from a dish-type plate 708 and a double-wall funnel 709.

The upper side of the dish-type plate 708 has a concave surface in the form of a spherical segment with the radius almost identical to that of the metal convex spherical cap 707. In such a way, the metal convex spherical cap 707 of T-piece 705 and the concave surface of the dish-type plate 708 together forms a spherical joint.

The lower surface of the dish-type plate 708 is covered with layer 710 of solar radiation absorption coating.

The upper edge of the internal wall of the double-wall funnel 709 is joined with the edge of the dish-type plate 708 and the edge of its outer wall is provided with flange 711.

The distal (lower) aperture of the double-wall funnel 709 is glazed with glazing 712.

There is a bearing housing 713 with a split lower flange 714 and two longitudinal slots; this bearing housing 713 is mounted on the thermal insulation 706 of T-piece 705.

Flanges 714 and 711 of the bearing housing 713 and of the outer wall of the double-wall funnel 709 are joined by a flexible joint 715, which plays at the same time a role of a thermal insulator.

The outer wall of the double-wall funnel 709 serves at the same time for mounting truss struts 716, which in turn serve for installation of a dish-type concentrating mirror with its frame.

FIG. 8 shows a cross-section of a combined unit of a T-piece—solar radiation receiver with application of a single-wall funnel and a dish-type radiation absorption plate.

It comprises bearing pipes 801 and 802 with insulting layers 803 and 804; and T-piece 805 with an insulating layer 806. The lower branch of T-piece 805 is sealed by a metal convex spherical cap 807. In addition, there is a solar radiation receiving member, which constructed from a dish-type plate 808 and a single-wall funnel 809.

The upper side of the dish-type plate 808 has the concave surface in the form of a spherical segment with the radius almost identical to that of the metal convex spherical cap 807. In such a way, the combination of the metal convex spherical cap 807 of the T-piece and the concave surface of the dish-type plate 808 together form a spherical joint.

The lower surface of the dish-type plate 808 is covered with layer 810 of a solar radiation absorption coating.

The lower edge of the single-wall funnel 809 is joined with a connecting branch 811 with flange 812, which is joined in turn with the lower flange of a flexible joint 813. Truss struts 814 are joined in this case with the connecting branch 811, which serve in turn for installation of a dish-type concentrating mirror with its frame (not shown).

The distal (lower) aperture of the single-wall funnel 809 is glazed with glazing 815.

There is a bearing housing 816 with a split lower flange 817 and two longitudinal slots; this bearing housing 816 is mounted on the thermal insulation 806. The split lower flange 817 of the bearing housing 816 is joined with the flexible joint 813, which plays at the same time a role of a thermal insulator serving in turn for installation of a dish-type concentrating mirror with its frame (not shown).

FIG. 9 is a cross-section of a combined unit featuring a T-piece—solar radiation receiver with application of a metal convex spherical cap for absorption of concentrated solar radiation.

It comprises bearing pipes 901 and 902 with insulting layers 903 and 904; T-piece 905 with an insulating layer 906, the lower branch of T-piece 905 is sealed by a metal convex spherical cap 907.

The outer surface of the metal convex spherical cap 907 is provided with a radiation absorption coating 908.

There is a double-wall funnel 909; the upper edge of this double-wall funnel is in immediate contact with the radiation absorption coating 908 of the metal convex spherical cap 907, and the double wall funnel 909 can be turned in two directions around this metal convex spherical cap 907.

In such a way, the combination of the metal convex spherical cap 907 of T-piece 905 and the double-wall funnel 909 forms a spherical joint.

The outer edge of the outer wall of the double-wall funnel 909 is. provided with flange 910.

The distal (lower) aperture of the double-wall funnel 909 is glazed with glazing 911.

There is a bearing housing 912 with a split lower flange 913 and two longitudinal slots; this bearing housing 912 is mounted on the thermal insulation 906 of T-piece 905.

Flanges 913 and 910 of the bearing housing 912 and of the outer wall of the double-wall funnel 909 are joined by a flexible joint 914, which plays at the same time a role of a thermal insulator. The outer wall of the double-wall funnel 909 serves at the same time for mounting truss struts 915, which serve in turn for installation of a dish-type concentrating mirror with its frame.

FIG. 10 shows a longitudinal cross-section of the solar radiation collector module with a concentrating compound-curvature unit and with some elements of a tracking mechanism.

It comprises bearing pipes 1001 with expansion units 1021, which are mounted on vertical posts 1002. A working medium flows in the bearing pipes 1001. The bearing pipes 1001 are provided with layers 1003 of a thermal insulation.

T-piece 1004 is built into the bearing pipes 1001. The lower branch of T-piece 1004 is sealed by a metal convex spherical cap 1005.

T-piece 1004 is covered with layer 1006 of a thermal insulation.

In addition, there is a solar radiation receiving member, which constructed from a dish-type plate 1007 and a double-wall funnel 1008.

The upper side of the dish-type plate 1007 has the concave surface in the form of a spherical segment with the radius almost identical to that of the metal convex spherical cap 1005. In such a way, the combination of the metal convex spherical cap 1005 and the concave surface of the dish-type plate 1007 forms a spherical joint.

The lower surface of the dish-type plate 1007 is covered with layer 608 of a solar radiation absorption coating.

The upper edge of the internal wall of the double-wall funnel 1008 is joined with the edge of the dish-type plate 1007 and the edge of its outer wall is provided with flange 1009.

The distal (lower) aperture of the double-wall funnel 1008 is glazed by glazing 1010 in order to diminish heat losses via its internal cavity.

There is a bearing housing 1011 with a split lower flange 1012 and two longitudinal slots; this bearing housing 1011 is mounted on the thermal insulation 1006 of T-piece 1004.

The open sections of the longitudinal slots of the bearing housing 1011 are closed. The flanges 1012 and 1009 of the bearing housing 1011 and of the outer wall of the double-wall funnel 1008 are joined by a flexible joint 1013, which plays at the same time a role of a thermal insulator.

The outer wall of the double-wall funnel 1008 serves at the same time for mounting truss struts 1014, which in turn serve for installation of a dish-type concentrating mirror 1015 with its frame 1016.

Frame 1016 of the dish-type concentrating mirror 1015 is joined through cylindrical hinges 1019 and 1020 with tracking rods 1017 and 1018.

Other embodiments and configurations may be devised without departing from the spirit of the invention and the scope of appended claims.

Claims

1. A solar radiation modular collector comprising: a concentrating unit of the single-curvature type; a receiver of concentrated solar radiation, said receiver comprising: a metal pipe with inlet and outlet connections, with a black or selective coating of the outer surface of said metal pipe; a thermal insulation intended to insulate thermally at least a portion of said metal pipe; said thermal insulation comprising a metal envelope with a vacuum-insulated internal cavity; said metal envelope comprising elongated internal and external sections, which are joined by two elongated connection straps and sealed at their ends by face planes; said internal elongated section comprising a cylindrical sub-section, which encloses a significant part of said metal pipe; said cylindrical sub-section featuring flat or single-curved strips with a certain angle of convergence with respect to said cylindrical sub-section; wherein said elongated external section encloses said metal pipe and the internal cavity between said elongated internal and external sections is evacuated in order to suppress convective and conductive losses of heat from said metal pipe; wherein the gap between the distal longitudinal margins of said flat or single-curved strips is glazed by a glazing; wherein said internal and external sections of said metal envelope are provided with corrugations, which decrease in dimension in the vicinity of said connection straps; and wherein said receiver is positioned in the zone of the focal line of said single-curvature concentrator; and a set of truss struts joining said concentrating unit with said metal envelope.

2. A solar radiation modular collector of claim 1, wherein said metal pipe is provided at end sections with a plurality of flexible sections in order to compensate for thermal expansion.

3. A solar radiation modular collector of claim 1, wherein said metal pipe is provided with a set of low circular ribs in order to prevent immediate contact of said black or selective coating with the inner surface of said elongated internal section.

4. A solar radiation modular collector of claim 3, wherein the cylindrical surfaces of said circular ribs are provided with an antifriction coating.

5. A solar radiation modular collector of claim 1, wherein the ends of said metal pipe are provided with flanges.

6. A solar radiation modular collector of claim 1, further comprising an auxiliary means for installation of said concentrating unit, said metal pipe and said metal envelope.

7. The collector of claim 6, wherein said metal pipe is installed on two posts, which serve as said auxiliary means, and said metal envelope can rotate around said metal pipe.

8. A solar radiation modular collector of claim 1, wherein the outer surface of said external section of said metal envelope is provided with a selective coating, which absorbs concentrated solar radiation.

9. A solar radiation modular collector of claim 1, wherein reflecting shields from metal foil are positioned in said internal cavity of said metal envelope.

10. A solar radiation modular collector of claim 9, wherein said internal cavity of said metal envelope is filled with gas.

11. A solar radiation modular collector of claim 10, wherein said gas has low thermal conductivity.

12. A solar radiation modular collector of claim 1, wherein said internal cavity is filled with powdered solid material.

13. A solar radiation modular collector of claim 1, wherein the extreme sections of said metal pipe are provided with threads instead of said flanges.

14. A solar radiation modular collector of claim 1, wherein there are some said metal envelopes situated around one said metal pipe, and, correspondingly, there are some said concentrating units, which are joined with said metal envelopes.

15. A solar radiation modular collector of claim 1, further comprising a tracking unit for tracking the sun by said concentrating unit.

16. A solar radiation collector system comprising a plurality of said solar radiation modular collectors of claim 1; said plurality solar radiation modular collectors are placed in the form of parallel rows and said metal pipes are interconnected in series in each said row.

17. A solar radiation collector system of claim 16, further comprising a common tracking unit for said collectors.

18. A solar radiation modular collector comprising: a concentrating unit of the compound-curvature type with a frame; a bearing pipe with an inlet and outlet connections and flexible joints at its extreme sections for compensation of its thermal expansion, for transport of heat by a working medium; wherein said bearing pipe is provided with a thermal insulation layer; posts for mounting said bearing pipe; wherein said bearing pipe comprises tubular members and T-pieces, installed between each pair of the neighboring tubular members; wherein the lower branch of each said T-piece is sealed by a metal convex spherical cap and a part of its outer surface of the T-piece is covered with a thermal insulation layer; a solar radiation receiving unit, which is constructed from a dish-type plate and a double-wall funnel; wherein the upper side of said dish-type plate has the concave surface in the form of a spherical segment with the radius commensurate with that of said metal convex spherical cap, thereby forming a spherical joint; wherein the lower surface of said dish-type plate is covered with a layer of solar radiation absorption coating; wherein the upper edge of the internal wall of said double-wall funnel is joined with the edge of said dish-type plate and the edge of its outer wall is provided with a flange; a glazing of the distal (lower) aperture of said double-wall funnel; a bearing housing with a split lower flange and two longitudinal slots; said bearing housing being mounted on said thermal insulation layer of said T-piece; a clamp, which closes the open sections of said bearing housing; a flexible joint that joins said split lower flange of said bearing housing and said flange of said double-wall funnel; and a tracking unit for tracking the sun by said concentrating unit of the compound-curvature type; said tracking unit comprising tracking rods, which are joined by hinges with said frame.

19. A solar radiation modular collector of claim 18, wherein the internal surface of said internal wall of said double-wall funnel has a high value of light reflection coefficient.

20. A solar radiation modular collector comprising: a concentrating unit of the compound-curvature type with a frame; a bearing pipe with an inlet and outlet connections and flexible joints at its extreme sections for compensation of its thermal expansion, for transport of heat by a working medium; wherein said bearing pipe is provided with a thermal insulation layer; posts for mounting said bearing pipe; wherein said bearing pipe comprises tubular members and T-pieces, installed between each pair of the neighboring tubular members; wherein the lower branch of each said T-piece is sealed by a metal convex spherical cap and a part of its outer surface of the T-piece is covered with a thermal insulation layer; a solar radiation receiving unit, which is constructed from a double-wall funnel; wherein the upper side of said dish-type plate has the concave surface in the form of a spherical segment with the radius commensurate with that of said metal convex spherical cap, thereby forming a spherical joint; wherein the lower surface of said dish-type plate is covered with a layer of solar radiation absorption coating; wherein the upper edge of the internal wall of said double-wall funnel is joined with the edge of said dish-type plate and the edge of its outer wall is provided with a flange; and wherein the outer surface of said metal convex spherical cap is provided with a radiation absorption coating and said radiation absorption coating is stable against friction with the upper edge of said double-wall funnel; a glazing of the distal (lower) aperture of said double-wall funnel; a bearing housing with a split lower flange and two longitudinal slots; said bearing housing being mounted on said thermal insulation layer of said T-piece; a clamp, which closes the open sections of said bearing housing; a flexible joint that joins said split lower flange of said bearing housing and said flange of said double-wall funnel; and a tracking unit for tracking the sun by said concentrating unit of the compound-curvature type; said tracking unit comprising tracking rods, which are joined by hinges with said frame.

21. A solar radiation modular collector comprising, a concentrating unit of the compound-curvature type with a frame; a bearing pipe with an inlet and outlet connections and flexible joints at its extreme sections for compensation of its thermal expansion, for transport of heat by a working medium; wherein said bearing pipe is provided with a thermal insulation layer; posts for mounting said bearing pipe; wherein said bearing pipe comprises tubular members and T-pieces, installed between each pair of the neighboring tubular members; wherein the lower branch of each said T-piece is sealed by a metal convex spherical cap and a part of its outer surface of the T-piece is covered with a thermal insulation layer; a solar radiation receiving unit, which is constructed from a dish-type plate and a single-wall funnel; wherein the upper side of said dish-type plate has the concave surface in the form of a spherical segment with the radius commensurate with that of said metal convex spherical cap, thereby forming a spherical joint; wherein the lower surface of said dish-type plate is covered with a layer of solar radiation absorption coating; a glazing of the distal (lower) aperture of said double-wall funnel; a bearing housing with a split lower flange and two longitudinal slots; said bearing housing being mounted on said thermal insulation layer of said T-piece; a clamp, which closes the open sections of said bearing housing; a flexible joint that joins said split lower flange of said bearing housing and said flange of said double-wall funnel; and a tracking unit for tracking the sun by said concentrating unit of the compound-curvature type; said tracking unit comprising tracking rods, which are joined by hinges with said frame; wherein the lower edge of said single-wall funnel is joined with the lower flange of said flexible joint; said truss struts are joined in this case with said connecting branch.

22. A solar radiation collector system comprising a plurality of said solar radiation modular collectors of claim 18; wherein said plurality of solar radiation modular collectors are in parallel rows; said bearing pipes are interconnected in series in each said row; said solar radiation modular collectors, which are positioned in parallel or belong to said one set of interconnected serial bearing pipes have common tracking units.