CN108662797B - Heat storage type flat plate solar heat collector - Google Patents

Abstract

The invention relates to a heat storage type flat plate solar collector which comprises an aluminum frame body, a transparent glass cover plate, a photovoltaic assembly, a heat absorption plate, a PCM (pulse code modulation) heat storage unit and a flow channel, wherein the middle part and the upper part of the inner side of the aluminum frame body are fixedly supported and connected with the transparent glass cover plate and the heat absorption plate through clamping grooves respectively; the photovoltaic module is arranged on the heat absorbing plate, the PCM heat storage unit is filled below the heat absorbing plate, and the PCM heat storage unit is connected with an inlet and an outlet of a cooling medium on the side face of the aluminum frame body through a flow channel and is used for realizing the integrated comprehensive utilization of solar photovoltaic photo-heat and heat storage. The solar energy heat storage device combines PCM heat storage with photovoltaic photo-thermal technology, effectively reduces temperature fluctuation of a photovoltaic cell, improves photoelectric conversion efficiency, realizes heat storage integration of a solar energy utilization device, overcomes the challenges of instability, intermittence and the like of solar energy, can be used as a stable heat source, meets the multi-period requirements of users on heat and temperature, has a simple structure, is convenient to use, is easy to combine with a building, and is beneficial to vigorous development and popularization.

Description

Thermal storage flat plate solar collector

technical field

The invention relates to the field of high-efficiency utilization of solar energy and phase-change energy storage, in particular to a heat-storage flat-plate solar heat collector.

Background technique

As an important form of renewable energy, solar energy has the advantages of energy saving and environmental protection, and it is of great significance to develop corresponding high-efficiency collection and utilization devices. Studies have shown that the increase in the temperature of photovoltaic cells reduces their photoelectric conversion efficiency. By using different cooling methods to cool photovoltaic cells, part of the waste heat can be used while ensuring the photoelectric conversion efficiency, realizing the multi-level utilization of solar energy, with considerable advantages. development prospects.

The flat-panel photovoltaic photothermal integrated solar collector has a simple structure, low cost, and is easy to combine with buildings. In traditional household solar energy systems, there is generally a hot water storage tank for display heat storage, so as to alleviate the insufficiency that the collector cannot provide heat continuously and stably when the solar flux density is too low or fluctuates greatly. However, as an independent device, the hot water storage tank has many parts, and the installation area is too large; if the hot water storage tank is not used in the solar energy system, due to the instability of environmental factors, the temperature of the cooling medium outlet will fluctuate greatly. It can not meet the requirements of heat on different times; on the other hand, the cooling medium cannot be circulated and heated, and can not meet the user's requirements on temperature. Therefore, the structural design of integrated heat collection and storage needs to be vigorously developed.

The temperature of the phase change material is almost constant during the phase change process, and at the same time it absorbs or releases a great latent heat. It is used as a latent heat storage material and has better heat storage capacity per unit volume than sensible heat storage methods such as hot water storage tanks. . Selecting a suitable PCM (phase change material) as a cooling medium can reduce the temperature fluctuation of photovoltaic cells, and at the same time achieve efficient heat storage, alleviate the phenomenon of insufficient heat supply when the solar energy is weakened, and can be used as a stable heat source to meet users' concerns about heat and temperature multi-period requirements.

The Chinese Patent Publication No. "104949351A" discloses an energy storage type flat plate heat collector. The energy storage module is designed inside the heat collector, which simplifies the solar water heating system. However, this patent only considers the collection, storage and use of heat, and fails to couple photovoltaic components in the system to achieve efficient use of solar energy.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies in the above-mentioned background technology, the present invention provides a heat storage type flat-panel solar collector with a simple structure and a detachable structure, which combines PCM and photovoltaic photothermal technology, optimizes the performance of photovoltaic cells, and achieves high efficiency. It has the function of heat storage, and adopts the overall structure design of flat plate, which is easy to be combined with the building.

In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:

A heat-storage flat-panel solar collector, comprising an aluminum frame, a transparent glass cover, a photovoltaic module, a heat absorbing plate, a PCM heat storage unit and a flow channel, the inner middle and the upper part of the aluminum frame respectively pass through The card slot is fixed and supported to connect the transparent glass cover plate and the heat absorption plate; the photovoltaic module is placed on the heat absorption plate, and the PCM heat storage unit is filled under the heat absorption plate. The outlet connection is used to realize the comprehensive utilization of solar photovoltaic photothermal and heat storage integration.

Further, the transparent glass cover plate and the heat absorbing plate are respectively bonded to the upper surfaces of the two card slots.

Further, the aluminum frame body is a single-sided detachable structure, and the outer side is fixedly connected with angle iron and bolts. To prevent the leakage of the PCM, the contact part of the frame body is sealed with a rubber gasket interlayer.

Further, the glass cover plate is made of tempered glass with high light transmittance, and the heat absorbing plate is made of red copper or aluminum.

Further, the photovoltaic module is composed of EVA glue, photovoltaic cells, EVA glue and a transparent back sheet are sequentially combined into one body by hot pressing.

Further, the upper surface of the heat absorbing plate is bonded to the photovoltaic module by uniformly smearing thermally conductive silica gel with high thermal conductivity.

Further, the PCM heat storage unit is a solid-state encapsulated PCM heat storage unit using urea-formaldehyde resin as the wall material of the microcapsule, or a PCM heat storage unit that has not undergone solid-state encapsulation processing.

Further, the PCM phase change material in the PCM heat storage unit is selected from inorganic salts or organic paraffins.

Further, the PCM heat storage unit that has not undergone solid-state encapsulation processing adopts a copper serpentine coil tube, and the solid-state encapsulated PCM heat storage unit forms a flow channel through an upper mold opening and cutting.

Further, an enhanced heat exchange structure or a material with high thermal conductivity is added in the PCM heat storage unit, so as to improve the heat charging and discharging rate of the PCM.

The beneficial effects of the present invention are as follows: a novel flat-plate solar collector for heat storage with a simple and detachable overall structure is provided, and the phase-change material is used as a cooling medium to cool the photovoltaic cell and reduce its temperature fluctuation, and at the same time The integrated function of heat storage is realized, which can be used as a stable heat source, alleviates problems such as environmental fluctuations, and meets the multi-period requirements of users on heat and temperature. Practical application, making it easier to combine with architecture.

The invention combines PCM heat storage with photovoltaic photothermal technology, effectively reduces the temperature fluctuation of photovoltaic cells, improves photoelectric conversion efficiency, realizes the integration of heat storage of solar energy utilization devices, and overcomes challenges such as instability and intermittentness of solar energy. , can be used as a stable heat source to meet the multi-period needs of users on heat and temperature. Its structure is simple, easy to use, and easier to combine with buildings, which is conducive to vigorous development and promotion.

Description of drawings:

Fig. 1 is the exploded schematic diagram of the detachable three-dimensional frame structure of the thermal storage type flat-plate solar collector of the present invention;

2 is a schematic structural diagram of a non-solid encapsulated PCM heat storage unit of the heat storage flat-plate solar collector of the present invention;

3 is a schematic structural diagram of a solid-state package PCM heat storage unit of the heat storage flat-plate solar collector of the present invention;

4 is a schematic diagram of a flow channel in an unpackaged PCM heat storage unit of the present invention;

FIG. 5 is a schematic diagram of a mold opening flow channel of the packaged PCM heat storage unit of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, a detailed description is given below with reference to the accompanying drawings. To ensure the simplicity of the attached images, some structures are not shown in the attached drawings.

As shown in FIG. 1 to FIG. 5 , the novel heat storage flat-panel solar collector of the present invention includes an aluminum frame body 1, a transparent glass cover plate 2, an air layer 3, an EVA glue 4, a photovoltaic cell panel 5, and an EVA glue 6. Transparent back plate 7, heat absorbing plate 8, solid-state packaged PCM heat storage unit 9, angle iron 10, bolts 11, card slots 12, flow channel inlet and outlet of solid-state packaged PCM 13, PCM heat storage without solid-state package Unit 14 , flow channel 15 made of mold opening and cutting, copper fins 16 , copper flow channel 17 , copper flow channel inlet and outlet 18 , insulation layer 19 . A card slot 12 is installed at the corresponding position on the inner side of the aluminum frame body 1. The extension wings at both ends of the card slot 12 are connected with the inner wall of the aluminum frame body 1 by bolts 11. The inner middle and upper part of the aluminum frame body 1 are fixed and supported by the card slot 12 respectively. Connect the transparent glass cover plate 2 and the heat absorption plate 8, the photovoltaic module 6 is placed on the heat absorption plate 8, and the PCM heat storage unit is placed under the heat absorption plate 8. The PCM heat storage unit passes through the flow channel and the cooling medium on the side of the aluminum frame. The import and export connection is used to realize the comprehensive utilization of solar photovoltaic photothermal and heat storage integration.

Preferably, the card slot 12 is made of aluminum. The surrounding sides of the aluminum frame body 1 are covered with a thermal insulation layer 19 to prevent heat dissipation. In addition, the side positions of the aluminum frame body 1 are reserved for the flow channel inlet and outlet 13 and the copper flow channel inlet and outlet 18 for the solid-state package PCM of the cooling medium.

As shown in Figure 1, the aluminum frame body 1 is designed with a detachable structure on one side, and there are tapping through holes in the corresponding positions around the outside. The fixed connection between each surface is realized by the angle iron 10 and the bolt 11. Rubber gasket to prevent the leakage of PCM, and the detachable structure is conducive to the replacement and maintenance of engineering materials. A card slot 12 is installed inside the aluminum frame body 1, and the upper surface of the card slot is evenly coated with temperature-resistant glass glue for bonding the transparent glass cover plate 2 to ensure the sealing and stability of the structure. Similarly, the lower card slot 12 is used to fix and support the heat absorbing plate 8. The upper surface of the card slot can be smoothed with sandpaper first, and high-strength epoxy resin AB glue can be applied evenly for bonding. Preferably, the transparent glass cover plate 2 is made of tempered glass material with high light transmittance, which is used to reduce the heat loss of convection and radiation, and can avoid the damage to photovoltaic modules caused by harsh environmental factors such as external dust and rainfall; 8 Choose copper or aluminum material.

The photovoltaic module combines the EVA glue 4, the photovoltaic cell 5, the EVA glue 6, and the transparent back plate 7 into one in turn through the thermal lamination technology. The photovoltaic module can be bonded to the heat absorbing plate 8 through the thermal conductive silica gel with high thermal conductivity, which plays the role of fixed support and heat transfer.

As shown in Figure 2, the PCM heat storage unit 14 that has not undergone solid encapsulation has an obvious visible solid-liquid separation interface during the phase change process. When the equipment is installed, it needs to be heated to a liquid state to fill the PCM into the container, and the filling is completed. The presence of a large amount of air should be avoided to reduce its impact on the overall heat transfer performance. Due to the plasticity of the unpackaged PCM, the heat absorbing plate is welded with a copper fin 16 structure to increase the heat exchange area, strengthen the heat exchange, and improve the heat charging and discharging rate of the PCM.

As a preference, the type of the phase change material of the PCM in the PCM heat storage unit can be selected from inorganic salts or organic paraffins, and its thermal properties should be selected according to different environments and functions.

As a preference, heat transfer can also be enhanced by adding materials with high thermal conductivity to the PCM phase change material, such as metal foam, expanded graphite, carbon nanotubes, and the like.

As shown in Figure 4, as an option, this unpackaged PCM heat storage unit uses a copper serpentine coil flow channel, the coil is close to the upper and lower walls, and is connected with the heat absorbing plate 8 by a welding process to prevent the cooling medium from flowing. vibration and instability problems.

As shown in FIG. 3 , another form of the PCM heat storage unit is a PCM heat storage unit 9 in which urea-formaldehyde resin is used as a microcapsule wall material in a solid state package. The phase transition process cannot be observed, and the overall shape is like a solid, and will not change. As shown in Fig. 5, different forms of flow channel structures can be produced at the upper end of the mold by opening and undercutting, so as to realize the integration of the energy storage material and the flow channel. In addition, in this structure, the cooling medium is in direct contact with the heat-absorbing plate, which reduces the above-mentioned problems such as excessive thermal resistance when the copper pipe flow channel is in line contact with the heat-absorbing plate. At the same time, the solid-state encapsulated PCM heat storage unit can be directly combined with the building wall, and there is no need to consider problems such as leakage when the solid-liquid phase transition occurs.

As shown in Figures 4 and 5, preferably, two ends of the different flow channels are respectively connected to the cold water inlet and the hot water outlet.

Claims (9)

1. The utility model provides a flat plate type solar collector of detachable heat accumulation formula, includes aluminium system framework, transparent glass apron, photovoltaic module, absorber plate, PCM heat-retaining unit and runner, its characterized in that: clamping grooves are arranged at corresponding positions on the inner side surface of the aluminum frame body, winglets extending from two ends of each clamping groove are connected with the inner wall of the aluminum frame body through bolts, and the middle part and the upper part of the inner side of the aluminum frame body are fixedly supported and connected with the transparent glass cover plate and the heat absorbing plate through the clamping grooves respectively; the solar photovoltaic heat storage device comprises an aluminum frame body, a heat absorption plate, a PCM heat storage unit, a flow channel, a heat storage layer and a heat storage layer, wherein a photovoltaic assembly is arranged on the heat absorption plate, the PCM heat storage unit is filled below the heat absorption plate, and the PCM heat storage unit is connected with an inlet and an outlet of a cooling medium on the side surface of the aluminum frame body through the flow channel and is used; the side surfaces of the periphery of the aluminum frame body are covered with heat insulation layers to prevent heat from dissipating; the aluminium system framework is unilateral detachable construction, and angle bar and bolt fixed connection are used in the outside, for preventing that PCM reveals, and the framework contact site is sealed with the rubber gasket intermediate layer, the detachable construction of aluminium system framework is favorable to the change and the maintenance of material in the engineering.

2. The detachable thermal storage flat plate type solar thermal collector according to claim 1, characterized in that: the transparent glass cover plate and the heat absorbing plate are respectively bonded on the upper surfaces of the two clamping grooves.

3. The detachable heat storage type flat plate solar collector according to claim 1, wherein the glass cover plate is made of tempered glass with high light transmittance, and the heat absorbing plate is made of red copper or aluminum.

4. The detachable thermal storage flat plate type solar thermal collector according to claim 1, characterized in that: the photovoltaic module is formed by sequentially combining EVA adhesive, a photovoltaic cell, EVA adhesive and a transparent back plate into a whole through hot pressing.

5. The thermal storage flat plate type solar thermal collector according to claim 1, characterized in that: the upper surface of the heat absorbing plate is bonded with the photovoltaic module through uniformly coating heat-conducting silica gel with high heat conductivity coefficient.

6. The detachable thermal storage flat plate type solar thermal collector according to claim 1, characterized in that: the PCM heat storage unit is a solid-state packaging PCM heat storage unit which takes urea resin as a microcapsule wall material, or a PCM heat storage unit which is not subjected to solid-state packaging treatment.

7. The detachable thermal storage flat plate type solar thermal collector according to claim 6, wherein: the PCM phase-change material in the PCM heat storage unit is inorganic salt or organic paraffin.

8. The detachable thermal storage flat plate type solar thermal collector according to claim 6, wherein: the PCM heat storage unit which is not subjected to solid packaging treatment adopts a snake-shaped coil made of red copper, and the PCM heat storage unit subjected to solid packaging forms a flow channel by opening a die and cutting the upper part of the PCM heat storage unit.

9. The detachable heat storage type flat plate type solar heat collector according to any one of claims 1 to 8, wherein: and a heat exchange strengthening structure or a material with high heat conductivity is arranged in the PCM heat storage unit and used for improving the heat charge and discharge rate of the PCM.

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