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WO2014160585A1 - Collecteur solaire - Google Patents

Collecteur solaire Download PDF

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Publication number
WO2014160585A1
WO2014160585A1 PCT/US2014/031337 US2014031337W WO2014160585A1 WO 2014160585 A1 WO2014160585 A1 WO 2014160585A1 US 2014031337 W US2014031337 W US 2014031337W WO 2014160585 A1 WO2014160585 A1 WO 2014160585A1
Authority
WO
WIPO (PCT)
Prior art keywords
solar energy
collector
sheath
energy collector
receiving tube
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2014/031337
Other languages
English (en)
Inventor
Phillip C. Watts
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Watts Thermoelectric LLC
Original Assignee
Watts Thermoelectric LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Watts Thermoelectric LLC filed Critical Watts Thermoelectric LLC
Publication of WO2014160585A1 publication Critical patent/WO2014160585A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D11/00—Central heating systems using heat accumulated in storage masses
    • F24D11/002—Central heating systems using heat accumulated in storage masses water heating system
    • F24D11/003—Central heating systems using heat accumulated in storage masses water heating system combined with solar energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D17/00—Domestic hot-water supply systems
    • F24D17/0015—Domestic hot-water supply systems using solar energy
    • F24D17/0021—Domestic hot-water supply systems using solar energy with accumulation of the heated water
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D19/00—Details
    • F24D19/10—Arrangement or mounting of control or safety devices
    • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
    • F24D19/1051—Arrangement or mounting of control or safety devices for water heating systems for domestic hot water
    • F24D19/1057—Arrangement or mounting of control or safety devices for water heating systems for domestic hot water the system uses solar energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F24H15/212—Temperature of the water
    • F24H15/223—Temperature of the water in the water storage tank
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
    • F24H15/335—Control of pumps, e.g. on-off control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S10/00—Solar heat collectors using working fluids
    • F24S10/40—Solar heat collectors using working fluids in absorbing elements surrounded by transparent enclosures, e.g. evacuated solar collectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S10/00—Solar heat collectors using working fluids
    • F24S10/70—Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits
    • F24S10/73—Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits the tubular conduits being of plastic material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
    • F24S40/50—Preventing overheating or overpressure
    • F24S40/55—Arrangements for cooling, e.g. by using external heat dissipating means or internal cooling circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
    • F24S40/60—Arrangements for draining the working fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S50/00—Arrangements for controlling solar heat collectors
    • F24S50/40—Arrangements for controlling solar heat collectors responsive to temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S80/00—Details, accessories or component parts of solar heat collectors not provided for in groups F24S10/00-F24S70/00
    • F24S80/20—Working fluids specially adapted for solar heat collectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S80/00—Details, accessories or component parts of solar heat collectors not provided for in groups F24S10/00-F24S70/00
    • F24S80/30—Arrangements for connecting the fluid circuits of solar collectors with each other or with other components, e.g. pipe connections; Fluid distributing means, e.g. headers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S80/00—Details, accessories or component parts of solar heat collectors not provided for in groups F24S10/00-F24S70/00
    • F24S80/50—Elements for transmitting incoming solar rays and preventing outgoing heat radiation; Transparent coverings
    • F24S80/52—Elements for transmitting incoming solar rays and preventing outgoing heat radiation; Transparent coverings characterised by the material
    • F24S80/525—Elements for transmitting incoming solar rays and preventing outgoing heat radiation; Transparent coverings characterised by the material made of plastics
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
    • F24T10/00—Geothermal collectors
    • F24T10/10—Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D2200/00—Heat sources or energy sources
    • F24D2200/11—Geothermal energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D2200/00—Heat sources or energy sources
    • F24D2200/14—Solar energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/10—Control of fluid heaters characterised by the purpose of the control
    • F24H15/136—Defrosting or de-icing; Preventing freezing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/10—Control of fluid heaters characterised by the purpose of the control
    • F24H15/174—Supplying heated water with desired temperature or desired range of temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
    • F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S2023/86—Arrangements for concentrating solar-rays for solar heat collectors with reflectors in the form of reflective coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2255/00—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes
    • F28F2255/20—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes with nanostructures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/20—Solar thermal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/40—Geothermal heat-pumps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/10—Geothermal energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/40—Solar thermal energy, e.g. solar towers
    • Y02E10/44—Heat exchange systems

Definitions

  • Sunlight provides a source of renewable, clean, and freely available energy useful in a variety of applications, including water heating, space heating, electricity generation, and other areas.
  • Devices for collecting and concentrating solar energy have been developed to take advantage of the ready availability of this energy source.
  • flat panel collectors are often used in low temperature applications such as space heating and domestic water heating.
  • Concentrating collectors may be used in higher temperature applications such as electric power generation, industrial process heating, and other applications.
  • Conventional flat panel collectors have a number of disadvantages. For example, they are typically made of relatively expensive materials such as copper, aluminum, and glass due to requirements for strength and thermal conductivity. Flat panel collectors are also typically provided in relatively large form factors, for example up to four by eight feet, and thus may be difficult to integrate into architectural designs.
  • a solar energy collector comprises an elongate plastic receiving tube configured to carry a heat transfer fluid, and an elongate clear plastic tubular sheath surrounding the receiving tube.
  • the sheath is of a larger cross section than the receiving tube such that a generally annular air space is formed between the receiving tube and the sheath.
  • the sheath has a front side configured to be disposed toward the sun and a back side opposite the front side.
  • the solar energy collector further includes a reflective coating partially covering a portion of the inside surface of the tubular sheath at the back side of the tubular sheath and configured such that when sunlight is directed at the front side of the sheath, a first portion of the sunlight transmitted through the sheath strikes the receiving tube directly, and a second portion of the sunlight transmitted through the sheath strikes the reflective coating and is redirected to the receiving tube.
  • the receiving tube is made of black polyethylene tubing.
  • the sheath may be made of clear polycarbonate tubing.
  • both the receiving tube and the sheath have circular cross sections.
  • a solar energy collector includes a plurality of elongate plastic receiving tubes configured to carry a heat transfer fluid.
  • the solar energy collector also includes a plurality of elongate clear plastic tubular sheaths, each sheath surrounding a respective one of the plurality of receiving tubes, each sheath being of a larger cross section than its respective receiving tube such that a generally annular air space is formed between sheath and the receiving tube.
  • Each sheath has a front side configured to be disposed toward the sun and a back side opposite the front side.
  • the solar energy collector further includes an inlet manifold including an inlet opening for receiving the heat transfer fluid to be heated and a plurality of outlet openings, and an outlet manifold including a plurality of inlet openings and an outlet opening.
  • Each of the plurality of receiving tubes is coupled between one of the plurality of outlet openings of the inlet manifold and one of the plurality of inlet openings of the outlet manifold.
  • the inlet and outlet manifolds are made of plastic.
  • the plurality of receiving tubes are disposed parallel to each other to form a rectangular collector unit.
  • the inlet manifold, the outlet manifold, the plurality of receiving tubes, and the plurality of sheaths are comprised in a first collector unit, and the solar energy collector comprises one or more additional collector units of like construction to the first collector unit, the inlet manifolds of the one or more additional collector units operatively coupled to the inlet manifold of the first collector unit and the outlet manifolds of the one or more additional collector units operatively coupled to the outlet manifold of the first collector unit.
  • gaps exist between adjacent members of the plurality of sheaths.
  • the solar energy collector may have an aspect ratio of at least 3: 1.
  • the solar energy collector may have an aspect ratio of at least 5: 1.
  • a solar energy collection system includes a solar energy collector comprising an elongate plastic receiving tube surrounded by an elongate clear plastic sheath.
  • the sheath is of a larger cross section than the receiving tube such that a generally annular air space is formed between the receiving tube and the sheath.
  • the sheath has a front side configured to be disposed toward the sun and a back side opposite the front side and a reflective coating partially covering a portion of the inside surface of the tubular sheath at the back side such that when sunlight is directed at the front side of the sheath, a first portion of the sunlight transmitted through the sheath strikes the receiving tube directly, and a second portion of the sunlight transmitted through the sheath strikes the reflective coating and is redirected to the receiving tube.
  • the solar energy collection system further includes a supply of the heat transfer fluid to be heated by the solar energy collector.
  • the solar energy collector comprises a plurality of elongate plastic receiving tubes, each surrounded by a respective elongate clear plastic sheath, the plurality of sheaths and receiving tubes are arranged in parallel such that the solar energy collector is rectangular, and the solar energy collector comprises an inlet manifold and an outlet manifold to direct the heat transfer fluid through the parallel receiving tubes.
  • the heat transfer fluid may be water comprising nanoparticles.
  • the solar energy collection system may further include an ion generator to generate the nanoparticles.
  • the solar energy collection system further includes a tank for holding the supply of heat transfer fluid, a supply pipe for carrying heat transfer fluid from the tank to the solar energy collector, a return pipe for carrying the heat transfer fluid from the solar energy collector to the tank, a circulation pump for circulating the heat transfer fluid between the solar energy collector and the tank through the supply pile and the return pipe, and a controller that controls the operation of the circulation pump based at least in part on the temperature of the heat transfer fluid in the tank and the temperature of the solar energy collector.
  • the controller may be configured to determine when the solar energy collector reaches a stagnation condition and in response to the determination, enter a stagnation remediation mode.
  • the solar energy collection system further includes a source of cooling fluid, wherein during the stagnation remediation mode, the cooling fluid is circulated through the solar energy collector without passing through the tank.
  • the solar energy collection system further includes a ground coupled heat exchanger, wherein in the stagnation remediation mode, the cooling fluid is circulated through the solar energy collector and the ground coupled heat exchanger without passing through the tank.
  • the ground coupled heat exchanger comprises a piping loop connected between the supply pipe and the return pipe, and the system further comprises a set of valves operated by the controller to isolate the tank during the stagnation remediation mode.
  • the solar energy collection system further includes a photovoltaic panel that supplies power to operate the controller and the circulation pump.
  • the solar energy collection system further includes a root zone heating loop, wherein the system circulates the heat transfer fluid through the root zone heating loop to heat the root zone of plants.
  • a method of collecting solar energy includes providing a solar energy collector.
  • the solar energy collector includes one or more elongate plastic receiving tubes each surrounded by a respective elongate clear plastic sheath.
  • Each respective sheath is of a larger cross section than its respective receiving tube such that a generally annular air space is formed between the receiving tube and the sheath, the sheath having a front side configured to be disposed toward the sun and a back side opposite the front side and a reflective coating partially covering a portion of the inside surface of the tubular sheath at the back side such that when sunlight is directed at the front side of the sheath, a first portion of the sunlight transmitted through the sheath strikes the receiving tube directly, and a second portion of the sunlight transmitted through the sheath strikes the reflective coating and is redirected to the receiving tube.
  • the method further comprises installing the solar energy collector in a location that receives sunlight, and passing a heat transfer fluid through the solar energy collector to be heated by the sunlight.
  • the solar energy collector has an aspect ratio of at least 3: 1, and installing the solar energy collector in a location that receives sunlight comprises installing the solar energy collector in a location that cannot accommodate a collector of equal area having a significantly smaller aspect ratio. In some embodiments, the solar energy collector has an aspect ratio of at least 5: 1, and installing the solar energy collector in a location that receives sunlight comprises installing the solar energy collector in a location that cannot accommodate a collector of equal area having a significantly smaller aspect ratio.
  • FIG. 1 illustrates a collector unit, in accordance with embodiments of the invention.
  • FIG. 2 shows a partially exploded view of one end of the example collector unit of FIG. 2, and illustrates some additional details of the construction of the collector unit of FIG. 1.
  • FIG. 3 shows a sectional view of the collector unit of FIG. 1, and illustrates additional aspects of its operation.
  • FIG. 4 illustrates other examples of receiving tubes and sheaths according to embodiments of the invention.
  • FIG. 5 illustrates combining several collector units like the collector unit of FIG. 1 into a larger collector, in accordance with embodiments of the invention.
  • FIG. 6 illustrates a system including an installation of the collector of FIG. 5 on a roof, used for heating water in accordance with embodiments of the invention.
  • FIG. 7 illustrates a system for solar heating of domestic hot water, in accordance with embodiments of the invention.
  • FIG. 8 illustrates a system that uses a ground coupled heat exchanger to provide cooling fluid to a collector, in accordance with embodiments of the invention.
  • FIG. 9 shows a collector in accordance with another embodiment of the invention.
  • FIG. 10 illustrates a solar energy collection system adapted for root zone heating, in accordance with embodiments of the invention.
  • Embodiments of the invention provide a solar collector made of low-cost, lightweight polymer materials.
  • FIG. 1 illustrates a collector unit 100, in accordance with embodiments of the invention.
  • Collector unit 100 includes an inlet manifold 101 and an outlet manifold 102.
  • a heat transfer fluid enters inlet manifold 101 through inlet opening 104, travels through receiving tubes not visible in FIG. 1, where it is heated by the sun 103.
  • the heat transfer fluid then exits outlet manifold 102 through outlet opening 105.
  • Some of the heat transfer fluid may continue through inlet manifold 101 to one or more additional collector units similar to collector unit 100, as will be described in more detail below.
  • FIG. 2 shows a partially exploded view of one end of example collector unit 100, including outlet manifold 102, and illustrates some additional details of the construction of collector unit 100.
  • Outlet manifold 102 is preferably made of injection molded plastic, for example a polymer such as polycarbonate, nylon, ABS, or another suitable polymer. The polymer may be reinforced, for example with glass fibers.
  • outlet manifold incudes four side tubes 201 (only one of which is visible in FIG. 2), and another end opening 202.
  • the particular configuration of outlet manifold 102 may also be called a "multi- port tee".
  • Each side tube and the ends of outlet manifold 102 include fittings for joining tubes, caps, or other item.
  • FIG. 1 shows a partially exploded view of one end of example collector unit 100, including outlet manifold 102, and illustrates some additional details of the construction of collector unit 100.
  • Outlet manifold 102 is preferably made of injection molded plastic, for example a polymer such as polycarbon
  • outlet manifold 102 could be a 4-outlet, 3 ⁇ 4 inch molded flow-through multi-port tee available from Uponor North America of Apple Valley, Minnesota, USA, and having fittings for attaching PEX tubing. Any other suitable kind of manifold may be used, for example a manifold having a different number of openings. In some embodiments, metal manifolds may be used.
  • Collector unit 100 also includes four elongate receiving tubes 203, one for each of side tubes 201.
  • receiving tubes 203 may be made of flexible 1/2 inch black polyethylene pipe, which is manufactured in lengths up to hundreds of feet, and is typically packaged in rolls. The black color of the pipe may facilitate absorption of solar energy.
  • Receiving tubes 203 may be connected to outlet manifold 102 in any suitable way, for example using crimp clamps 204 (only two of which are visible in FIG. 2).
  • Collector unit 100 further includes four elongate clear plastic tubular sheaths 205, one surrounding each receiving tube 203.
  • Sheaths 205 are a form of glazing and may be made, for example, of clear polycarbonate tubing or another suitable material that is transparent to sunlight or nearly so.
  • sheaths 205 may have a circular cross section with a diameter of about 1.25 - 1.5 inches, although other sizes may be used in other embodiments.
  • One side of the inside surface of each sheath 205 is coated with a reflective coating 206.
  • Reflective coating 206 may be made, for example, of an adhesive-backed aluminum foil, aluminized Mylar, or another suitable reflecting material.
  • Insulating spacers 207 may be fitted over receiving tubes 203, to maintain the spacing of sheaths 205 to their respective receiving tubes 203, and to provide an insulating function.
  • Insulating spacers 207 may be made, for example, of a urethane foam or another suitable material. While insulating spacers 207 are shown in FIG. 2 only at the ends of sheathes 205, additional spacers could be placed at other locations along the length of collector unit 100. [0022]
  • FIG. 3 shows a section view of collector unit 100, and illustrates additional aspects of its operation. As is apparent in FIG.
  • sheaths 205 thus perform multiple functions. They lend structure and stiffness to collector unit 100, by virtue of their larger diameter than receiving tubes 103. Sheaths 205 also serve to reduce heat loss from receiving tubes 103, protecting receiving tubes 103 from breezes that would remove heat, and forming a generally annular air space 302, which may further insulate receiving tube 103. In addition, sheaths 105 support reflective coating 206, which effectively increases the effective collection area of collector unit 100, as compared to a collector lacking reflective coatings 206.
  • receiving tubes 203 and sheaths 205 are shown as circularly cylindrical perfectly co-axial, but this is not a requirement.
  • Tubes and sheaths having other cross sectional shapes may be utilized, for example elliptical, polygonal, or other shapes.
  • a sheath having a parabolic trough shape on its underside may be used.
  • a shape including an involute of the collector tube may be used.
  • cylindrical sheaths may be preferred for simplicity, cost, or other reasons.
  • Polycarbonate tubes designed for protection of fluorescent light bulbs may be used in some embodiments, and are readily available at low cost.
  • the spaces between receiving tubes 203 and sheaths 205 are annular, being the space between two co-axial cylinders, but this is not a requirement, and in other embodiments, the space between the receiving tube and sheath may be only generally annular.
  • the term "generally annular" is intended to encompass the arrangement as shown in FIG. 3, where receiving tubes 203 and sheaths 205 are perfectly cylindrical and perfectly co-axial, such that air space 302 is truly annular in the mathematical sense, but also to encompass spaces defined when the sheaths surround the receiving tubes but are not perfectly co-axial, and spaces defined when the receiving tube, sheath, or both are not cylindrical.
  • FIG. 4 illustrates other examples of receiving tubes 401a-401d that are surrounded by sheaths 402a-402d, forming generally annular spaces 403a-403b between receiving tubes 401a- 40 Id and sheaths 402a-402d. Many other arrangements may be used within the scope of the appended claims.
  • FIG. 5 illustrates combining several collector units like collector unit 100 into a larger collector 500, in accordance with embodiments of the invention.
  • Collector 500 includes three collector units, including collector unit 100, joined using at their inlet and outlet manifolds. Heat transfer fluid can enter at inlet opening 104, travel in parallel through the receiving tubes of collector 500, and exit at outlet opening 105 after having been heated by the sun 103.
  • Collectors of other desired sizes can be constructed by joining other numbers of collector units 100.
  • each collector unit uses receiving tubes and sheaths about four feet long, and spaced about 1.5 inches apart, so that each collector unit 100 is about six inches wide and about four feet long, and collector 500 is about 18 inches wide and about four feet long.
  • Other sizes and spacings may be used as well as other numbers of collector units, to form a collector of any workable size.
  • FIG. 6 illustrates a solar energy collection system 600 including an installation of collector 500 on a roof 601, used for heating water in accordance with embodiments of the invention.
  • system 600 heats a supply of heat transfer fluid 602 in tank 603.
  • Heat transfer fluid 602 is drawn out of tank 603 and pumped by circulation pump 604 through supply pipe 605 to collector 500.
  • Heat transfer fluid 602 is heated by solar energy in collector 500, and flows out of collector 500 and back to tank 603 through return pipe 606.
  • tank 603, collector 500, and the associated piping form a closed system.
  • Heat transfer fluid 602 may be used as a heat reservoir to provide a heat source for thermoelectric power generation, hydronic heating, root zone heating of plants, or for other uses.
  • Pipes 605 and 606, as well as the manifolds of collector 500 are preferably insulated to avoid heat loss, but no insulation is shown in FIG. 6 for clarity of illustration.
  • a controller 608 receives signals indicating the temperature of heat transfer fluid 602 in tank 603, and the temperature of collector 500. If heat transfer fluid 602 in tank 603 is not at its desired temperature, and collector 500 is at a temperature higher than the temperature in tank 603, controller 602 causes circulation pump 604 to run so that the available energy at collector 500 is used to heat tank 602. In some
  • a photovoltaic panel 612 may be used to power controller 608 and circulation pump 604.
  • heat transfer fluid 602 is water. Because collector 500 is mounted on roof 601 and exposed to the elements, water in collector 500 could be subjected to freezing temperatures.
  • tank 603 is located in a conditioned space, and system 600 operates as a "drain back" system. A volume of air may be included in the system, sufficient to fill collector 500 and the portions of pipes 605 and 606 that are above roof 601 and subject to freezing.
  • collector 500 is mounted in such a way that corner 609 is the lowest portion of collector 500, so that heat transfer fluid 602 can drain as completely as possible from collector 500 by gravity.
  • a vacuum breaker valve may be placed collector 500, for example at topmost corner 613, to admit air to collector 500 during drain back, to speed the drain back of heat transfer fluid 602.
  • collector 500 is made primarily of plastic materials, which have much lower thermal conductivity than traditional collector materials.
  • plastic materials for the purposes of this disclosure, to be made primarily of plastic materials means that the receiving, fluid distribution, and glazing components of the collector are made of polymer materials.
  • Some metal parts may be used in a collector that is made primarily of plastic materials, for example for reflective coatings, clamps, mounting hardware, and other incidental functions.
  • the primarily plastic construction of a collector in accordance with embodiments of the invention may afford advantages in material cost, shipping cost, and ease of assembly of the collector.
  • the light weight of the collector may enable mounting lighter mounting hardware, and mounting the collector in locations that would not support a heavier collector made of traditional materials.
  • a model collector made according to an embodiment of the invention has proved surprisingly effective, especially in light of the low cost of its components.
  • a system similar to system 600 was constructed including a collector made the manner shown in FIGS. 1 and 2.
  • the collector included four parallel receiving tubes 20 feet long, and thus had a collecting aperture totaling 10.73 square feet.
  • the system was tested on three sunny days in late winter of 2013 in Longmont, Colorado, to heat water in a tank. Performance was evaluated by measuring the temperature of the tank, operating the collector to heat the tank, again measuring the temperature of the tank, and calculating the amount of energy delivered to the water in the tank from the change in temperature and the mass of water.
  • the system delivered an average of 6684 BTUs of thermal energy to the tank, or 623 BTUs per square foot of collector aperture area. In each test, the system was operated for about 5.5 hours, and the outdoor temperature reached about 57-60 °F.
  • the performance of a system embodying the invention can be further improved by enhancing the heat transfer characteristics of heat transfer fluid 602.
  • One especially effective and economical technique for enhancing the thermal conductivity and convective heat transfer characteristics of water is to convert the water to a nanofluid having suspended nanoparticles. Techniques for generating nanoparticles in water are described in co-pending U.S. Patent
  • an ion generator 610 includes two sterling silver electrodes 611 that are suspended in heat transfer fluid 602. Electrodes 611 may be positioned in tank 603, in one of pipes 605 and 606, or at another convenient location in the system. It may be advantageous to place the electrodes at a location where heat transfer fluid 602 flows regularly.
  • Ion generator 610 contains circuitry that impresses an alternating voltage between the two electrodes, causing the electrodes to shed ions by electrolytic action.
  • the ions are nanoparticles.
  • the flow of heat transfer fluid 602 distributes the nanoparticles throughout the system. The presence of nanoparticles significantly enhances the heat transfer characteristics of the water, and therefore improves the performance of the system.
  • FIG. 7 An example of such a system 700 is shown in FIG. 7.
  • System 700 includes a heat exchanger 701 to isolate the heat transfer fluid that flows through collector 500 from domestic hot water 702 in tank 603.
  • electrodes 611 of ion generator 610 are positioned in pipe 605, rather than in tank 603.
  • a drainback tank 703 is provided, so the heat transfer fluid circulating to collector 500 can drain completely back into the conditioned space in times of freezing weather.
  • the heat transfer fluid flowing through collector 500 could be treated with an anti-freeze additive, in which case the closed loop could be completely filled and not drain back tank would be necessary.
  • FIG. 8 illustrates a system 800 that uses a ground coupled heat exchanger in the form of piping loop 801 to provide cooling fluid to collector 500, in accordance with embodiments of the invention.
  • Ground coupled piping loop 801 may be, for example, a length of plastic pipe buried in a trench a few feet deep, packed with sand, and covered with earth. The temperature of soil underground tends to remain very stable throughout the year, typically about 57 °F in many parts of the United States. The earth can therefore act as a large heat source or heat sink.
  • controller 608 monitors the temperature of heat transfer fluid 602 in tank 603, and also the temperature of collector 500. When stagnation is detected, for example when tank 603 is at its maximum desired temperature and collector 500 exceeds a safe operating temperature, controller 608 enters a stagnation remediation mode. In one example embodiment, controller 608 may enter the stagnation remediation mode when collector 500 exceeds 120 °F, although other criteria may be used. [0043] In the stagnation remediation mode, circulation pump 604 is shut off. Preferably after a short delay, two normally-open valves 802 and 803 are switched closed under control of controller 608, to isolate tank 603. Second pump 804 is then started.
  • Piping loop 801 has been previously filled with water, so that water is drawn by second pump 804 from piping loop 801, travels up pipe 605 to collector 500 where it is heated and cools the collector, and travels down pipe 606. Because normally-open valve 802 is closed, the water travels through pipe 805 back to piping loop 801 to give up heat and circulate for another cycle through collector 500 if needed. It is envisioned that only a few minutes of cooling will be required at any one time to bring collector 500 back to a safe temperature, and that the energy consumption of second pump 804 and valves 802 and 803 will therefore be small.
  • an additional, redundant pump 806 may be installed in parallel with second pump 804. Controller 608 may sense whether pump 804 is operating properly and if not, redundant pump 806 would be started, to ensure that collector 500 is properly cooled. In some embodiments, emergency battery power could be used to operate the system during power outages.
  • the stagnation remediation mode may also be used for freeze protection. That is, heat transfer fluid could be circulated through piping loop 801 and through the collector in times of freezing temperatures. Instead of cooling the collector to prevent damage from stagnation, the circulating fluid would be heated by the ground loop and would warm the collector to prevent damage from freezing. In some embodiments, no additional hardware would be necessary. The additional control logic could simply be programmed into controller 608.
  • controller 608 is described above as being programmable, the system may also be implemented by a set of temperature sensors and logical connections between them, without requiring a programmable element such as a microprocessor.
  • a differential temperature sensor may compare the temperatures of the collector and tank, and generate a logic level indicating whether the collector is warmer or cooler than the tank. That signal would be routed to a drive circuit for circulation pump 604, and circulation pump 604 would run when the collector is warmer than the tank, but would not run otherwise.
  • the drive signal could be further gated by other logic signals.
  • another differential sensor could compare the tank temperature to a desired upper limit value, and generate a logic level indicating whether the tank is at the desired temperature or not.
  • controller encompass both programmable devices and control logic implemented by discrete components.
  • controller 608 may be programmed or otherwise configured to implement the following control scheme:
  • collector 500 shown in FIGS. 5-8 is in a rectangular configuration, the invention is not so limited, and it will be appreciated that the construction techniques and materials described above provide opportunities for configuration and customization of collectors, and may enable use of solar collectors in locations that were not previously convenient.
  • FIG. 9 shows a collector 900 in accordance with another embodiment of the invention.
  • Collector 900 includes a single elongate receiving tube 901 surrounded by a sheath 902.
  • Receiving tube 901 may be made from a continuous plastic pipe, or may include splices.
  • sheath 902 may also include splices, and periodic spacers 903 may be used to maintain space between receiving tube 901 and sheath 902 if desired.
  • Sheath 902 also preferably includes a reflective coating 904 on one side, to enhance the collection efficiency of collector 900, as described above.
  • Collector 900 is depicted as being about 1.5 inches in diameter and about eight feet long, but the length of the collector is limited only by the practicality of installing it and the ability to pump heat transfer fluid through the narrow receiving tube for long distances.
  • collector 900 may have length as much as 50, 100, 200, 500, or more times its width.
  • the ratio of the collector's length to its width may be called the collector's aspect ratio.
  • a collector such as collector 900 or another collector according to embodiments of the invention may be installed in places where a conventional collector panel could not.
  • collector 900 may be installed on top of a fence or wall, on a building ledge, on a building eave, or in another location that has good sun exposure but would not be convenient for mounting another kind of collector, for example a traditional flat panel collector having an aspect ratio of about 2: 1.
  • Collector 900 may be somewhat flexible, and could include right-angle or other angular bends through the use of simple and readily available fittings. Thus, solar energy may be utilized in an unobtrusive manner.
  • a long narrow collector installed on top of a wall would likely not be configured to drain completely by gravity. The stagnation remediation mode may be especially useful with such an installation to avoid freezing on winter nights, for example.
  • collectors Many other collector configurations are possible as well.
  • long narrow collectors having two, three, four, or another number of parallel receiving tubes and sheaths could be used, depending on the size and shape of the area available for mounting the collector.
  • Such collectors may have aspect ratios much larger than the typical conventional flat panel collector, for example 3: 1, 4: 1, 5: 1, 10: 1, 20: 1, 50: 1, 100: 1, 200: 1, 500: 1, or another aspect ratio, and may be installed in spaces that could not accommodate a collector of equal area having a significantly smaller aspect ratio.
  • a significantly smaller aspect ratio is any aspect ratio less than about 50 percent of the aspect ratio of the collector in question.
  • FIG. 10 illustrates a solar energy collection system 1000, adapted for root zone heating.
  • Solar energy collection system 1000 is illustrated as similar to system 600 shown in FIG. 6, with the addition of a root zone heating loop 1001.
  • a root zone heating pump 1002, under control of controller 608, circulates heat transfer fluid 602 from tank 603 through root zone heating loop 1001, delivering heat to roots 1003 of plants 1004.
  • Controller 608 may control pump 1002 intermittently, for example on a fixed schedule, or based on the relative temperatures of tank 603 and the soil beneath plants 1004.
  • root zone heating loop 1001 may be used in conjunction with stagnation remediation measures, for example as shown in FIG. 8.

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  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
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Abstract

L'invention porte sur un collecteur solaire, qui est réalisé principalement en matière plastique. Une large variété de configurations de collecteur peut être réalisée à partir de parties similaires, et, par conséquent, le collecteur peut être adapté au montage dans des emplacements où des collecteurs à panneau plat classiques ne peuvent pas être réalisables. Le collecteur peut, de façon pratique, être utilisé avec un nanofluide comme fluide de transfert de chaleur, de façon à accroître les caractéristiques de transfert de chaleur du fluide de transfert de chaleur. Un système de commande pour remédier à la stagnation, pour la protection contre le gel, ou les deux, peut être utilisé. Par exemple, quand le collecteur a un risque de stagnation ou de gel, de l'eau peut être amenée à circuler à travers une boucle d'échange de chaleur couplée au sol pour refroidir ou chauffer le collecteur. De préférence, le mode d'élimination de stagnation ne sacrifie pas l'énergie thermique précédemment collectée et stockée.
PCT/US2014/031337 2013-03-25 2014-03-20 Collecteur solaire Ceased WO2014160585A1 (fr)

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EP2557373A1 (fr) * 2011-08-11 2013-02-13 Universita'del Salento Fluide caloporteur avec nanofluides pour un système solaire thermodynamique
US8991049B2 (en) * 2011-12-16 2015-03-31 Combined Power LLC Systems and methods for installing solar energy systems
US10253286B2 (en) 2013-09-04 2019-04-09 Combined Power LLC Systems and methods of generating energy from solar radiation
US10358778B2 (en) * 2015-02-06 2019-07-23 Michael Gregory Theodore, Jr. Temperature controlled structure assembly
AT516890A1 (de) * 2015-02-12 2016-09-15 Liebhart Oskar Ing Elektrische Wasserpumpe
ITBO20150241A1 (it) * 2015-05-12 2016-11-12 Teleios Srl Impianto solare geotermico a bassa entalpia
CN118776127B (zh) * 2024-08-16 2025-01-14 江苏桑力太阳能产业有限公司 一种具有防冻功能的太阳能热水器及其防冻方法

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GB2048459A (en) * 1979-05-03 1980-12-10 Gunderson C F Solar heat collectors
US4528976A (en) * 1984-06-06 1985-07-16 Zomeworks Corporation Thermal control system for solar collector
CN201488320U (zh) * 2009-09-16 2010-05-26 海宁市三喜太阳能工业有限公司 银离子太阳能热水器
WO2012040778A1 (fr) * 2010-09-27 2012-04-05 Boss Polymer Technologies Pty Ltd Capteur solaire

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US4135537A (en) * 1978-03-20 1979-01-23 Atlantic Richfield Company Light collector
JPS5846365Y2 (ja) * 1979-12-22 1983-10-21 シャープ株式会社 太陽熱コレクタ

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GB2048459A (en) * 1979-05-03 1980-12-10 Gunderson C F Solar heat collectors
US4528976A (en) * 1984-06-06 1985-07-16 Zomeworks Corporation Thermal control system for solar collector
CN201488320U (zh) * 2009-09-16 2010-05-26 海宁市三喜太阳能工业有限公司 银离子太阳能热水器
WO2012040778A1 (fr) * 2010-09-27 2012-04-05 Boss Polymer Technologies Pty Ltd Capteur solaire

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