Classifications

• • 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
  • F24S40/57—Preventing overpressure in solar collector enclosures
• • 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
  • F24S40/53—Preventing overheating or overpressure by venting solar heat collector enclosures
• • 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

Definitions

• the present invention relates in general to solar heating installations and, more particularly, to a seal ⁇ ing and venting device in a ventilation gap between a solar heat permeable surface and a heat absorbing sur- face in a solar collector.
• a solar heating installation is dimensioned for sufficient capacity during the spring and autumn months, the installation will be overdimensioned for the warm summer months and underdimensioned for the cold winter months.
• the heat shortage during the win ⁇ ter months can be compensated for by a corresponding additional amount of heat which may be realized by means of some previously known conventional heating plant.
• a relatively large solar collector area is required for an acceptable heating supply also during the relatively cool marginal periods in the spring and autumn.
• a condition for attaining economic viabi ⁇ lity is that the price per square metre be kept low.
• One method of realizing this condition is to integrate the solar collector construction in a roof construc ⁇ tion such that the solar collector forms a part of the roofing material over a corresponding area of the roof.
• a further solution in a prior art solar collector element is to provide, between the "solar collector sur ⁇ face", that is to say the solar-permeable surface and the heat-absorbing surface, a gap open at two opposite ends, and to provide, at one of the open ends of the gap, an openable sealing valve leaf which is so arranged that it can be opened and closed by means of an operating device which is actuated in direct correspondence to the temperature level in the solar collector element.
• the gap is always open at its one end and is -opened at the other end for allowing the through-flow of air and there ⁇ by cooling the solar collector element, in that the valve leaf automatically opens when overheating is de ⁇ tected.
• the major object of the present invention is, by means of a relatively simple device, simultaneously to solve the problem of realizing efficient sealing of the ventilation gap, for example, at each of two op ⁇ posite ends, or, when necessary, about the entire cir- cumference of the gap, and to realize large inlet and outlet openings to and from the gap, respectively, when the situation requires large volumes of through-flow air.
• the sealing and venting device which is characterised by at least one elastical ⁇ ly deformable tubular member disposed in the ventila- tion gap and extending along at least one side of the gap; an apparatus for expanding the tubular member, by means of an expansion medium,into tight abutment • against the solar heat permeable and heat absorbing surfaces; and means for opening the gap for allowing the through-flow of air, these means consisting of a device for evacuating the expansion medium from the tubular member and a device for causing the tubular member to assume a substantially flattened-out state in abutment against but one of the above-mentioned surfaces.
• the gap is sealable and openable at two opposite sides by means of two apparatuses of the above-disclosed type.
• tubular sealing members of the same type can be disposed in the ventilation gap along all four sides, these four members possibly being formed by sections of a single expandable tubular mem- ber.
• these sections may, if desired, be ar ⁇ ranged such that only the two sections at the opposite ends of the. gap serve as openable venting devices as a result of evacuation of expansion medium in these latter sections.
• the expansion of the tubular member (or members) can, in one advantageous embodiment, be realized by air pressure.
• This air pressure is generated by the intermediary of water pressure by means of an elec ⁇ tric circulation pump which is normally used for pump- ing water in the water system in solar heating instal ⁇ lations.
• the apparatus for evacuating the expansion medium may comprise a normally closed evacua- 5 tion valve which is opened when the power supply to the circulation pump fails and/or when a certain water tem ⁇ perature is exceeded.
• a device may also be used for converting the solar heating element so as to operate as an air heat exchanger, in which event the ventilation gap is opened at its op ⁇ posite ends in order to allow warm ambient air to flow through the gap -in the element, this flow possibly being positively realized by means of a fan.
• expansion of the tubular members can be realized by means of air pressure in a pressure ves ⁇ sel in which the air pressure is generated by means of the water circulation pump by the intermediary of water pressure.
• this apparatus use may be made, for evacuation of the expansion medium, of suction which is realized in the pressure vessel on lowering of the pressure when the circulation pump ceases operat- ing, for example, in the event of a power failure.
• Fig. 1 is a fragmentary and schematic cross-sectional view showing a roof with a solar collector element in ⁇ tegrated in the. roof, and a device according to the pre ⁇ sent invention
• Fig. 2 is a fragmentary longitudinal sectional view taken along the line II-II in Fig. 1;
• Fig. 3 is schematic plan view of the element of Figs. 1 and 2, with a sealing device according to the invention which is disposed in the gap between the heat-permeable surface and heat-absorption surface of the solar collec ⁇ tor element, and of which two sections at the upper and lower ends of the gap form venting means;' and 6 Fig. 4 is a cross-section taken along the line IV-IV in Fig. 3.
• Fig. 1 shows a sloping roof with a bearing surface 1 which normally consists of transverse tongued and grooved timber.
• a solar collector is installed on the roof 1, the collector being generally designated 2 and comprising thermal insulation 3 disposed on the roof, for example, a layer of foamed polyurethane, a heat absorbing -bed 4 resting on the thermal insula- tion 3 and being provided with a series of water chan ⁇ nels 5, and an outer layer 6 disposed in spaced apart relationship to the heat-absorbing bed 4 and consist ⁇ ing of solar energy-permeable material, such as panels of glass or translucent plastic.
• the entire solar collector may be mounted direct on the bearing roof structure 1 but may also be in the form of one or more cassettes, so-called solar panels which may easily be mounted on the roof surface.
• Expandable tubular members 9a, 9b are disposed in a ventilation gap 8 between the heat-absorbing bed 4 and the outer layer 6, proximal the upper and lower ends of the solar collector. These members 9a, 9b may be of the same design. In the illustrated embo ⁇ diment, the members 9a, 9b form, at the ends of the gap 8, efficient sealing and venting devices which are in the form of hoses of rubber, plastic or other suit ⁇ able material. If it is considered desirable, these members may be .reinforced by fabric or the like. The hoses are-disposed such that, after expansion by means of an expansion medium, for example (or preferably) air, they form effective sealing devices between the bed 4 and the outer layer 6.
• an expansion medium for example (or preferably) air
• the hoses 9a, 9b serving as venting devices can be flattened out such that they assume a substantially recumbent position against the heat-absorbing bed 4, which is illustrated by means of dot-dash lines in Fig. 1.
• P ⁇ 7 9a, 9b serving as venting devices are expanded, they form efficient sealings against air circulation through the gap 8, and when they are contracted, the gap 8 forms an open ventilation channel for natural draught (by means of so-called chimney effect) for cooling the heat-ab ⁇ sorbing bed 4 so that injurious heating of the bed 4 and risk of boiling the water in the channels 5 will thereby be prevented in a manner which is as simple as it is effective.
• sealing for a square or rectangular solar collector element can be realized also at the side ' s of the gap 8 by means of two further hoses 9c, 9d which extend along the outer edges of the gap 8 (see Figs. 3 and 4) .
• these latter hoses can be permanently expanded, since in general they need not carry out any venting function. Possibly however, these two latter hoses 9c, 9d may also be disposed to be evacuated to form vents and they can also, together with the two first hoses 9a, 9b be formed from one . continuous hose.
• the hoses 9a, 9b may be designed such that they are normally in the form of planar, strip-formed members.
• Each hose may, for example, be manufactured from two 5-15 cm wide strips of plastic or rubber sheeting, for example butyl rubber, which have been vulcanized together along the edges.
• the hoses are nor ⁇ mally filled with air in order to form efficient seals in the gap 8 between the two layers 4 and 6 when 'con- ditions are such that the greatest possible heating from the sun is desired.
• the hoses When the ventilation gap 8 is to be kept closed, the hoses should be under a certain excess pressure in order to realize good sealing and when the hoses 9a, 9b serving as venting devices are fully evacuated, they should lie relatively flat against the heat absorbing bed 4. It may possibly be difficult to cause the hoses 9a, 9b to assume a flat position on the bed 4 merely by reducing the air pressure.
• a reliable flattening-out of the hoses may be realized by rendering the hoses resiliently retractable from the expanded to the flattened position.
• a spring means is intimated at 10 in Fig. 1 and may consist of one or more leaf springs which, on inflation of the hose are bent from one state of curvature by the intermediary of bistable plane to an opposite state of curvature in which the spring strives tohold the hose in abutment against the under- face of the outer layer 6.
• the spring is bent back by the intermediary of the bi ⁇ stable plane and is curved such that it strives to hold the hose taut and in abutment against the upper face of the bed 4.
• Pressure regulation of the hose 9 may be realized in several different manners. For example, it is pos ⁇ sible to employ an apparatus with a hand pump or pres- sure vessel and a safety valve which is opened by a temperature sensor at a certain temperature or by an electric sensor in the event of a failure of the power supply to the circulation pump which is normally used to cause the water to flow through the water channels 5.
• a manometer may also be used. In the event of a pres ⁇ sure increase in the water system caused by too high a temperature, the manometer senses this pressure change and opens the safety valve, the sealing hoses 9a, 9b serving as venting devices being emptied and opening the ventilation gap or gaps 8. After emptying, the safety valve can be closed and the hoses once again filled with air to the desired pressure. This may be 9 effected automatically when the temperature has fallen to a predetermined level.
• a compressor for pressure supply, use may be made, for example, as an alternative to the above-mentioned possibilities, of a compressor, in which case the system operates in principle in the same manner as that described above, but with the difference ' tha ' the compressor may be caused to start automatically when the temperature has fallen. It may be advantageous to use a pressure equa ⁇ lizer which is placed in a space having as-constant a temperature as possible, such that the pressure in the hoses is not influenced too much by the temperature in the solar collector. This is in order to reduce the risk that the -hoses 9 are compressed with far too high a pressure against the outer layer 6 in the event of strong sunshine.
• the pressure in the hoses 9 may be realized by means of air pres- sure which is exercised by water against an air cushion in a vessel.
• the water pressure may be realized by means of that circulation pump which is normally used in solar heating systems of the above-described type. Water could also be used as the pressure medium.
• a solar collector system according to the invention provided with ventilation gaps 8 may, by combination with a heat pump, be used as an air heat exchanger and thereby realize an acceptable degree of self-sufficiency during a large part of the winter. Many regions during the winter experience a number of cloudy but nevertheless mild days when the solar collector system can, without appreciable modification, be used in an efficient manner.
• the sealing and venting device can be evecuat- ed as a result of the impulse which the power failure provides, that is .to say a solenoid-operated valve may be used as the safety valve, in which the magnetic coil, on energization, normally holds the valve closed, where ⁇ as a spring opens " the valve in the event of a power failure.
• a solenoid-operated valve may be used as the safety valve, in which the magnetic coil, on energization, normally holds the valve closed, where ⁇ as a spring opens " the valve in the event of a power failure.
• the opposite mode of operation can also be achieved, that is to say such that the valve is normally kept closed when no current passes through, and such that the valve opens in the event of a failure of the power supply to the circulation pump.
• FIG. 3 and 4 schematically illustrate, at 11, air supply conduits which are connected to a compressed air source of the above-described type and lead to the hoses 9a-9d by the intermediary of non-return valves 12.
• the safety valves connected to the hoses 9a and 9b are shown at 13.
• non-return valves 12 use may be made of regulated valves which may be opened and closed, for example electrically, in order to permit also emptying via the air supply conduits. If a commu ⁇ nication line * between the two hoses 9a, 9b serving as venting devices is provided, only one of these or only the communication line need be provided with the above- mentioned valves 12, 13.
• the sealing hoses 9c and 9d which, in Fig.
• hoses of round section may be provided with solely filling and emptying valves 14 in conjunction with air supply and evacuation con ⁇ duits 15. Possibly, all of the hoses may be connected to a common air supply system equipped with suitable valves.
• the sealing and venting 11 device according to the invention may be used in a man ⁇ ner similar, to that described above between the heat- permeable and heat absorbing surfaces which define an air gap for heating air by means of solar heat through the outer layer 6 in Fig. 1.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Photovoltaic Devices (AREA)
• Roof Covering Using Slabs Or Stiff Sheets (AREA)

Applications Claiming Priority (4)

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• 1980
  • 1980-07-07 SE SE8004984A patent/SE8004984L/xx not_active Application Discontinuation
  • 1980-10-08 WO PCT/SE1980/000246 patent/WO1981001044A1/en unknown
  • 1980-10-08 EP EP80901904A patent/EP0039682A1/de not_active Withdrawn

Non-Patent Citations (1)

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