US20070235021A1

US20070235021A1 - Skylight/solar water heating apparatus

Info

Publication number: US20070235021A1
Application number: US11/717,593
Authority: US
Inventors: Laura Reed; Travis Beaudin; Eric Conklin
Original assignee: STC UNM
Current assignee: UNM Rainforest Innovations
Priority date: 2006-03-15
Filing date: 2007-03-13
Publication date: 2007-10-11

Abstract

A skylight/solar fluid (e.g. water) heating apparatus and method involve providing a housing adapted for mounting on a building and a light-transmitting outer cover on the housing so that light can enter the housing. A solar fluid heater is disposed in the housing interiorily of the cover in a manner to absorb solar radiation for heating a working fluid thereof and also to allow some light to pass through the housing into the building.

Description

This application claims benefits and priority of provisional application Ser. No. 60/782,453 filed Mar. 15, 2006, the entire disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to skylight/solar fluid heating apparatus adapted for positioning on a roof and/or wall of a building in a manner that incident solar radiation is both transmitted through the apparatus into the accommodating building and also absorbed by solar collecting components and transferred to a working fluid, such as water, for heating.

BACKGROUND OF THE INVENTION

A wide variety of skylight products currently are available for mounting on a roof or wall of a building in order to allow sunlight to pass through into the interior of the building to provide some natural lighting in the building.
A wide variety of solar water heating devices also are currently available for mounting on a roof or wall of a building. A typical solar water heating device includes piping through which water is passed in a manner that solar radiation absorbed by a fin, plate or other absorber of the device is transmitted to the water to heat it. In a typical service application, the solar water heating device is plumbed to a conventional electric or natural gas fired water heater in order to provide supplemental solar heated water thereto to reduce energy consumption of the water heater.

SUMMARY OF THE INVENTION

The present invention provides in one embodiment a skylight/solar fluid heating apparatus adapted for positioning on a building and including components arranged in a manner that solar radiation entering the apparatus can be used to heat a working fluid, such as water, and also can be passed through the apparatus into the building for interior lighting purposes.
In an illustrative embodiment, the skylight/solar fluid heating apparatus comprises a frame or housing adapted for mounting in or on a roof or wall on a building and a light-transmitting outer glazing or cover on the housing so that solar radiation can enter the housing. A solar fluid heater is disposed on the housing in a manner to collect solar energy for heating a working fluid and also to allow light to pass through the housing into the building. For example, the solar collector(s) typically include a fluid conduit to which thermal energy absorbed by the collector(s) is transferred to the working fluid in the conduit. Moreover, the solar collector(s) and/or their relation to the housing define open spaces or paths for light entering the housing to pass through the housing into the building. The solar fluid heater typically includes one or more solar collectors which can be arranged in any type of pattern and/or configuration on the housing to provide such open spaces or paths for light to pass into the building. Thermal insulation and/or glazing can be employed in the housing and/or on the one or more solar collectors to reduce heat transfer losses in operation of the apparatus.
In a particular embodiment of the present invention offered for purposes of illustration and not limitation, a plurality of solar collectors in the shape of light absorbing, thin metallic fins extend across a first dimension (e.g. a width dimension) of the housing and are spaced apart from one another along a second dimension (e.g. a length dimension) of the housing to provide the open spaces or paths through which light can pass into the building. The dimensions of the light absorbing fins and light-passing open spaces can be selected as desired to provide the dual benefit of collection of solar energy for heating a working fluid and transmission of light into a building to provide interior lighting. The spacing of the fins can be determined by the overall dimensions of the housing and the number of fins required to meet the design condition of the application.
The present invention also envisions a combination of a water heater (or other fluid heater) of a building and a plurality of the skylight/solar water heating apparatus described above disposed on the building in a manner to provide solar heated water or fluid thereto to reduce energy consumption. The invention also envisions connector piping or conduit for interconnecting rows of fluid conduit sections of solar collectors of adjacent skylight/solar water heating apparatus in a serial fluid flow manner.
Advantages of the present invention will become morse fully apparent from the following detailed description taken with the following drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of a skylight/solar fluid heating apparatus pursuant to an illustrative embodiment of the invention. The optional shade shown in FIG. 4 is omitted from FIG. 1 for convenience.
FIG. 2 is a perspective view of the assembled skylight/solar fluid heating apparatus of FIG. 1.
FIG. 2A is a perspective view similar to FIG. 2 with the outer glazing or cover removed to illustrate the solar collector fins and open spaces therebetween in more detail.
FIG. 3 is a perspective view of the assembled skylight/solar fluid heating apparatus disposed in a roof on a building.
FIG. 4 is a cross section of the assembled skylight/solar fluid heating apparatus schematically showing various components for purposes of illustration of the apparatus.
FIG. 5 is a schematic view of connector piping interconnecting rows of fluid conduit sections of solar collector fins of adjacent skylight/solar water heating apparatus in serial fluid flow manner according to an embodiment of the invention.

DESCRIPTION OF THE INVENTION

A skylight/solar fluid heating apparatus purusant to the present invention is advantageous to provide the dual benefit of collection of solar radiation for heating a working fluid and also of transmission of sunlight into a building to provide interior lighting. The skylight/solar fluid heating apparatus can be used in connection with any building which can include, but is not limited to, a home, apartment, garage, office, factory, or any other type of building. For purposes of illustration and not limitation, a plurality of such skylight/solar fluid heating apparatus can be disposed on a roof and/or wall on a building in a manner to provide solar heated water to a water heater of the building while providing interior lighting.
Referring to FIGS. 1-4, an illustrative embodiment of the skylight/solar fluid heating apparatus is shown including a frame or housing H having long and short frame sub-assemblies 1, 2 forming a rectangular frame or housing, although the invention can be practiced using a housing H having any appropriate shape for an intended service application. For purposes of illustration an not limitation, the sub-assemblies 1, 2 include long and short housing members 1 a, 2 a wherein the sub-assemblies are made of abutted 2×8 wood boards, or any other suitably sized wood members, having appropropriate dimensions to form the housing H when assembled. The wood members can be readily fastened together using wood screws, nails, adhesive, and the like to form the housing. In lieu of natural wood members, the housing members 1 a, 2 a can comprise composite wood/plastic members, fiberglass, plastic, metal, or any other suitable material for the service application involved.
As shown in FIGS. 1-4, the exterior surfaces of the housing H can be clad with aluminum, plastic, or other protective cladding sheet pieces 3, 4 to protect the housing members 1 a, 2 a from adverse effects of weather over a long time period of use of the apparatus. The long and short cladding pieces 3, 4 can be attached/sealed to the frame or housing members 1 a, 2 a, an outer light-transmitting cover 5, and each other with a commercially available window-caulking product that has a 50-year guarantee or by any other suitable cladding fastening/sealing system. Additional separate roof cladding sheet pieces 3′, 4′ can be provided to cooperate with the respective cladding sheet pieces 3, 4 to render the skylight/solar fluid heating apparatus weather-proof. Alternately, the cladding sheet pieces 3, 3′; 4, 4′ can be combined in a manner to provide a fewer number of cladding sheet pieces. The interior and exterior surfaces of the housing members 1 a, 2 a can be painted or treated in any suitable manner for cosmetic or other reasons.
The housing H is adapted to be mounted in or on a roof and/or wall on a building such as by being received and fastened in an opening in the roof or wall of the building in the same or similar manner that a conventional skylight unit is fastened, although the apparatus can be mounted on an exterior surface of the roof or wall with the roof or wall opening located adjacent thereto. Referring to FIG. 4, the long housing members 1 a can be fastened to respective adjacent roof rafters R using nails, screws and the like for purposes of illustration and not limitation. The terminology skylight/solar fluid heating apparatus as used herein is meant to include mounting of the apparatus not only in or on a building roof, but also mounting in or on a vertical or sloped building sidewall in a manner that may resemble a window or other sidewall structure for receiving solar radiation.
The skylight/solar heating apparatus includes a light-transmitting outer glazing or cover 5 disposed on the frame or housing H so that sunlight can enter the housing. The glazing or cover 5 can be transparent or translucent to incident sunlight to this end. For purposes of illustration and not limitation, the outer glazing or cover 5 can comprise a commercially available double-glazed, cellular polycarbonate sheet produced by Polygal Plastics Industires, Ltd. that transmits about 70% of incident sunlight, while substantially excluding tansmission of UV light however. A sheet thickness of ⅝ inch can be used to this end for purposes of illustration and not limitation.
An optional interior glazing sheet 6 can be provided between the outer cover 5 and the solar fluid heater S to further decrease heat loss from the apparatus. This interior glazing sheet 6 is optional depending on the winter temperature values of the location where the skylight/solar fluid heating apparatus is used. For purposes of illustration and not limitation, the interior glazing sheet 6 can comprise a single pane of tempered glass or any other suitbale glazing sheet.
The edges of the outer glazing or cover 5 and the optional inner glazing sheet 6 reside or rest in grooves 11 that can be notched out of the interior of the long and short housing members 1 a, 2 a as shown best in FIGS. 1 and 4. A suitable sealant or caulk can be provided in the grooves 11 if desired.
The solar fluid heater S is disposed on the housing H in a manner to collect light for solar heating a working fluid and also to allow light to pass through the housing into the building. As shown in FIGS. 1-4, the solar fluid heater is disposed below the outer glazing or cover 5 and optional inner glazing sheet 6 and toward the interior of the building when the apparatus is mounted on a roof of the building.
For purposes of illustration and not limitation, the solar fluid heater S is shown schematically in FIGS. 1-4 as comprising a plurality of thin, elongated metallic solar collector fins 7 extending across a first dimension (e.g. width dimension) of the housing H and spaced apart from one another along a second dimension (e.g. length dimension) of the housing to provide open spaces SO through which light can pass into the building. Each solar collector fin 7 is made of a heat conductive material, such as copper and/or aluminum, and includes a high absorptivity selective surface facing the outer glazing or cover 5. The fin selective surface can be coated with a coating material C, FIG. 4, that absorbs a high percentage of incident solar radiation and emits a small percentage of solar radiation. Each solar collector fin 7 typically includes a length of a heat conductive (e.g. copper or aluminum) fluid conduit section 12 a through which water or other working fluid is conveyed wherein the fluid conduit section 12 a can be formed integrally with the collector fin 7 or can be attached to the collector fin. The heat absorbed by each solar collector fin 7 is conducted to the fluid conduit section 12 a, which is attached metallurgically (e.g. soldering, brazing, welding, etc.) or otherwise in heat transfer relation to the associated solar collector fin 7 so as to conduct heat to the water or other working fluid in the fluid conduit. The fluid conduit section 12 a, if exposed, can be coated with the coating material C. It should be noted that FIGS. 1, 2A, and 4 illustrate the solar collector fins 7 and their fluid conduit sections 12 a in a schematic manner for convenience in showing these components. The solar collector fins used in an illustrative prototype apparatus each comprised a Sunstrip™ solar fin commercially available from Thermo Dynamics Ltd., 44 Borden Avenue, Dartmouth, Nova Scotia, Canada, wherein the fluid conduit section is metallurgically bonded/clad in the collector fin. A suitable coating material comprises a high absorptivity selective surface applied to the fins and can comprise a high absorptivity Anodic/Cobalt™ anodic surface coating provided by Thermo Dynamics Ltd. on the solar collector fins used in the prototype apparatus. Other suitable high absorptivity selective coating materials can include, but are not limited to, a high absorptivity so-called Black Crystal™ coating used in the RITH (Roof Integrated Thermosiphon) Technology Development program by Sandia National Laboratories, SOLKOTE™ HI/SORB™-II coating available from Solar Energy Corporation (SOLEC), 129 Walters Avenue, Ewing, N.J., black chrome coating, or any other suitable high absorptivity coating.
An optional foam thermal insulation layer 13 can be attached (e.g. by adhesive) to a undersurface of each solar collector fin 7 that faces away from the outer glazing or cover 5 toward the interior of the building. This optional insulation layer 13 can decrease heat loss from the solar collector fin.
Still further, an optional movable cellular shade C can be mounted on the housing H below the solar collector fins 7 to close off a portion or all of the housing H to reduce unwanted heat losses and gains from the skylight/solar fluid heating apparatus during operation. Such movable cellular shade C is commercially produced Hunter Douglas Inc. and includes tracks T that can be mounted by fasteners on the housing members 1 a.
Adjacent ends of adjacent fluid conduits 12 a of the solar collector fins 7 are connected by soldering or other leak-proof connection by a U-shaped fluid conduit section 12 b. The U-shaped fluid conduit sections 12 b each have a connector section 12 s and a pair integral leg sections 12 l that are received in passages 1 p provided in the long housing members la so as to be supported on the housing members 1 a. In FIGS. 1 and 2, a series of seven solar collector fins 7 and six copper U-shaped conduit sections 12 b are shown for purposes of illustration and not limitation. The solar collector fins 7 thereby are fixedly supported via the fluid conduit sections 12 a, 12 b on the housing. The exterior sides of the housing members 1 a can be provided with recesses 1 r to receive the U-shape fluid conduit sections 12 b so that they do not extend beyond the sides of the housing members 1 a when they are fastened to roof rafters.
The plumbing or piping of the skylight/solar fluid heating apparatus also includes a fluid inlet conduit 9 and fluid outlet conduit 10. The fluid inlet conduit 9 is connected by soldering or other leak-proof connection to the fluid conduit section 12 a of the lowermost solar collector fin 7 in FIG. 1. The fluid outlet conduit 10 is connected by soldering or other leak-proof connection to the fluid conduit section 12 a of the upperrmost solar collector fin 7 in FIG. 1. The inlet conduit 9 in turn is connected to a source of the working fluid. The outlet conduit 10 is connected to a user of solar heated fluid. For example, a skylight/solar water heating apparatus can be plumbed to a standard domestic water heater, which can be used as a supplementary system for hot water. The inlet conduit 9 is connected to a water supply pipe or conduit of the building and the outlet conduit 10 is connected to an electric or natural gas hot water heater HR. The outlet conduit 10 can be connected directly to the water heater if the water heater is placed above the skylight/solar heating apparatus. That is, no pump is required due to the thermosyphon effect. The benefit of a thermosyphon set up is that it requires no moving parts. Thermosyphoning causes a natural flow of the water through the water heating system. On the other hand, if the skylight/solar water heating apparatus is placed above the water heater, a pump is required to pump water through the system.
Another embodiment of the present invention involves connecting the skylight/solar fluid heating apparatus of the invention in a closed-loop, recirculating manner to a heat transfer coil or other heat transfer device (not shown) of a fluid (e.g. water) heater wherein a recirculation pump (not shown) is provided for circulating the working fluid between the fluid heater and the sklight/solar fluid heating apparatus. The working fluid can comprise water, a mixture of water and ethylene glycol, or any other suitable heat transfer working fluid.
As described above for purposes of illustration, the plurality of thin, elongated metallic solar collector fins 7 are shown spaced apart from one another along a second dimension (e.g. length dimension) of the housing H to provide open spaces SO through which light can pass into the building while the solar collector fins 7/fluid conduits 12 a are heating water or other working fluid. The dimension of each open spacing SO can be varied as desired for a particular service application to provide the dual benefit of collection of solar radiation for heating a working fluid and transmission of sunlight into a building to provide interior lighting. For purposes of illustration and not limitation, when the solar collector fins have dimensions of 6 inches×24 inches, the open spacing SO between adjacent solar collector fins 7 can be 1 (one) inch measured in the long direction of the housing H. The housing itself can have an internal width dimension of 24 inches and internal long dimension of 48 inches in this example.
Practice of the present invention is not limited to the type or the arrangement of solar collector fins 7 shown in FIGS. 1-4 and can be practiced with any type and/or configuration of one or more solar collector members where the solar collector members and/or their relation to the housing define open spaces or paths for light entering the housing to pass through the housing into the building. One or more solar collector members, such as the solar collector fins, pipes, and the like, can be arranged in any type of pattern and/or configuration on the housing to provide such open spaces or paths for light to pass into the building. For example, solar collector fins of the type described above and shown in FIG. 1 can be arranged in other than the series arrangement shown in FIGS. 1 and 2A. For example, the solar collector fins can be arranged to form a “picture-frame” border extending about the inner periphery of the housing so as to leave a reactangular, central open space in the housing for light to pass through into the building. Or, one or more solar collector fins can be suspended centrally in the housing to provide an open space between the outer periphery of the solar collector fins and the inner periphery of the housing that would provide a “picture-frame” lighting pattern into the building by virtue of the relation of the solar collector fin and the housing. Still further, the solar collector fins can be arranged in series extending between the short housing members 2 a to provide longitudinal open spaces, rather than between the long housing members 1 a to provide lateral open spaces.
Moreover, the invention envisions connecting the fluid conduit sections 12 a to the U-shaped fluid conduit sections 12 b in a manner that would permit manual or motor actuated pivoting of the fluid conduit sections 12 a and collector fins 7 carried thereon in the housing relative to the fixed U-shaped fluid conduit sections 12 b to vary the open spacing SO between adjacent collector fins and improve incident solar radiation collection. For example, a leak-proof rotary connection can be provided to this end between the fluid conduits 12 a and the U-shaped conduits 12 b.
The solar fluid heater can employ one or more solar collector members of a type different from the solar collector fins 7 described above. For example, the invention can be practiced with flate-plate solar collector members used in the RITH (Roof Integrated Thermosiphon) Technology Development program by Sandia National Laboratories, parabolic or other shaped solar collectors, and any other solar collector. Moreover, the skylight/solar fluid heating apparatus can be modified by using a reduced number of more efficient solar collector fins that provide greater heat transference to the water or other working fluid and reduce the number of solar collector fins needed. This modification can increase the distance between each solar collector fin 7 for example to provide more interior lighting of the building.
Four skylight/solar fluid heating apparatus of the type described above can be used on a building to transmit about the same amount of light as one standard two by four foot skylight. Moreover, three to four skylight/solar water heating apparatus of the type described above may provide 50-80% of the domestic hot water required for a household of four individuals depending upon the service conditions, such as angle of incidence and geographic location of the apparatus.
FIG. 5 provides a schematic view of connector piping or conduits CC for interconnecting rows of the fluid conduit sections 12 a of the solar collector fins (not shown) of four adjacent skylight/solar water heating units A1, A2, A3, A4 in serial fluid flow manner according to another embodiment of the invention. In this embodiment, lengths of connector piping conduits CC interconnect in series fluid flow the rows of fluid conduit sections 12 a of adjacent units A1, A2, A3, A4 so that, for example, the fluid conduit section 12 a of the bottom solar collector fin of unit A1 is connected in series water flow relation to the fluid conduit section 12 a of the bottom solar collector of the next adjacent unit A2, the fluid conduit section 12 a of the bottom solar collector fin of unit A2 is connected in series water flow relation to the fluid conduit section 12 a of the bottom solar collector of the next adjacent unit A3 and so on as represented by the arrows to provide a serial water flow through all of the fluid conduit sections 12 a of the units A1 through A4. U-shaped conduit sections 12 b are provided on the end units A1 and A4 to redirect the water flow as needed to achieve the overall serial flow through the fluid conduit sections 12 a of all of the units A1 through A4.
It is to be understood that the invention has been described with respect to certain specific embodiments thereof for purposes of illustration and not limitation. The present invention envisions that modifications, changes, and the like can be made therein without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. A skylight/solar fluid heating apparatus, comprising a housing adapted for mounting on a building, a light-transmitting outer cover on the housing so that light can enter the housing, and a solar fluid heater disposed on the housing in a manner to absorb solar radiation for heating a working fluid and to allow some light to pass through the housing into the building.

2. The apparatus of claim 1 wherein the solar fluid heater includes a plurality of solar collector members arranged relative to one another or to the housing to define one or more open spaces for transmitting light into the building.

3. The apparatus of claim 2 wherein the solar collector comprises a plurality of solar collector fins extending across a first dimension of the housing and spaced apart from one another along a second dimension of the housing to provide open spaces through which light can pass into the building.

4. The apparatus of claim 3 wherein each of the plurality of solar collector fins includes a section of the fluid conduit.

5. The apparatus of claim 4 wherein each section of the fluid conduit is connected to a U-shaped section of the fluid conduit that is supported on the housing.

6. The apparatus of claim 3 further including thermal insulation on the solar collector fins on a respective surface thereof facing toward the inside of the building.

7. The apparatus of claim 1 wherein the solar fluid heater includes a solar collector member connected in heat transfer relation to a fluid conduit that is connected to a water heater.

8. The apparatus of claim 1 further comprising a light-transmitting glazing sheet disposed in the housing between the outer cover and the solar fluid heater.

9. The apparatus of claim 8 wherein the glazing sheet is tempered glass or polycarbonate.

10. The apparatus of claim 1 further including a movable shade in the housing, said shade being deployed to reduce the amount of light passing into the building.

11. Combination of a fluid heater and a plurality of the skylight/solar fluid heating apparatus of claim 1 disposed on a building in a manner to provide solar heated fluid to the fluid heater.

12. The combination of claim 11 wherein the fluid heater comprises a water heater and the skylight/solar fluid heating apparatus provides solar heated water to the water heater.

13. The combination of claim 11 wherein the skylight/solar fluid heating apparatus are interconnected by connector piping to provide a serial fluid flow through fluid conduit sections thereof.

14. A method of using solar energy, comprising the steps of disposing a solar fluid heater on a housing that is mounted on a building such that light enters the housing, absorbing solar radiation entering the housing using the solar fluid heater for heating a working fluid thereof, and transmitting some light entering the housing into the building through one or more open spaces defined by solar collector members of the solar fluid heater and/or their relation with the housing.

15. The method of claim 14 including providing the solar fluid heater with a plurality of solar collector fins extending across a first dimension of the housing and spaced apart from one another along a second dimension of the housing to provide one or more open spaces through which light can pass into the building.

16. The combination of a plurality of solar fluid heating apparatus, each solar fluid heating apparatus comprising a solar fluid heater disposed to absorb solar radiation for heating a working fluid wherein the solar fluid heater comprises a plurality of solar collectors each having a respective fluid conduit section, wherein the fluid conduit section of the solar collector of the first of the plurality of the apparatus is fluid interconnected to the fluid conduit section of the corresponding solar collector of the next adjacent of the plurality of the apparatus and so on to provide a series fluid flow through the fluid conduit sections of all of the solar collectors.