CN101691954A - Pressure type vacuum panel solar thermal collector - Google Patents

Abstract

In the pressure-bearing vacuum flat plate solar collector, the glass cover plate (1) is composed of an upper glass cover plate (8), a lower glass cover plate (9), and surrounding sealing strips (5); the two opposite end baffles (2) and the two opposite side baffles (4), the glass cover plate (1) and the bottom plate (13) located on the upper and lower sides of the end baffle (2) and the side baffle (4) are in common position to form a Overall; the perfusion fan (3) is located on the end baffle (2), the non-return air valve (6) is located on the inner side of the side baffle (4), the bottom insulation layer (12) is located on the bottom plate (13), and the side insulation layer ( 14) Located inside the side baffle (4), a heat collecting plate (15) is provided on the bottom insulation layer (12), and a heat transfer tube (11) is provided on the upper surface of the heat collecting plate (15). (15) The lower surface is provided with heat transfer fins (16), and the aluminum tube band (10) is located below the heat collecting plate (15), and there are several heat pump working medium passages (17) in the aluminum tube band (10).

Description

Pressure-bearing vacuum flat plate solar collector

technical field

The pressurized vacuum flat plate solar collector consists of a double-layer vacuum glass plate as the cover plate, an extruded plastic insulation material as the bottom plate and edge sealing and heat preservation, and an aluminum flat tube belt as the medium flow channel. The invention belongs to the technical field of solar energy application, and in particular relates to the structural design of solar heat collectors and solar heat pump heat collectors/evaporators.

Background technique

Solar collectors are the main components of solar heat utilization.

The most widely used in China is the solar collector of glass vacuum tubes. With the intensification of energy problems, high-rise buildings urgently need to use solar collectors to provide domestic hot water or heating in winter, but ordinary glass vacuum tube collectors are not easy to match buildings perfectly. combined. The flat plate collector is more and more popular because of its beautiful appearance, easy laying on the top surface or facade of the building, and organic combination with the building. Ordinary solar flat collectors are covered with polycarbonate transparent cover or single-layer glass cover, and the solar radiation heat obtained is often lost to the air around the collector through radiation, heat conduction, and air convection on the outer surface of the glass. , so the heat collection efficiency of flat plate collectors is generally lower than that of glass vacuum tube collectors.

Another disadvantage of ordinary solar collectors is that when there is no solar radiation, or when the solar radiation is insufficient in winter, the collector cannot raise the water temperature to the required temperature due to insufficient radiation. In view of the defect that solar water heaters cannot provide hot water at a suitable temperature in rainy days, a solar-air composite heat source heat pump system has attracted the attention of many technicians. The solar heat pump uses the heat pump working medium to absorb solar radiation and evaporate in the heat collector. After increasing the pressure through the compressor, it condenses and releases heat at a high temperature, which can provide hot water at a higher temperature; when there is no solar radiation, the heat pump working medium can Absorb heat from the air to produce domestic hot water.

Therefore, it is necessary to develop a high-efficiency flat-plate heat collector that is conducive to the organic combination with buildings. This heat collector can be applied to ordinary solar water heaters, and can also be used as an evaporator for solar-air composite heat source heat pumps. Effectively provide hot water throughout the year.

Contents of the invention

Technical problem: The task of the present invention is to propose a novel pressurized vacuum flat panel solar collector suitable for solar-air compound heat source heat pumps. The heat collector has the characteristics of high efficiency, good antifreeze, and is not easy to break; and it can realize dual heat sources of solar energy and air, which solves the shortcomings of traditional solar water heaters that are affected by the weather and the system cannot run around the clock; The heat exchanger is integrated with the tube-belt heat exchanger and fins with high heat exchange efficiency. It can not only use water as the medium, as an ordinary solar water heater collector, but also use refrigerant as the medium (as an evaporator), Constitute solar-air composite heat source heat pump operation.

Technical solution: The pressure-bearing vacuum flat plate solar collector of the present invention includes a glass cover plate, an end baffle, a bottom plate, a perfusion fan, a side baffle, a non-return air valve, a bottom insulation layer, a side insulation layer, a heat collecting plate, Heat transfer tubes, aluminum tube strips, heat transfer fins; among them: the glass cover plate is composed of an upper glass cover plate, a lower glass cover plate, and surrounding sealing strips; two opposite end baffles and two opposite side baffles Enclosing a space, the glass cover plate and bottom plate are respectively located on the upper and lower sides of the end baffle and side baffle to form a whole; the perfusion fan is located on the end baffle, the non-return air valve is located on the inner side of the side baffle, and the bottom insulation layer is located On the bottom plate, the side insulation layer is located inside the side baffle, and a heat collecting plate is arranged on the bottom insulation layer, and a heat transfer tube is arranged on the upper surface of the heat collecting plate, and a heat transfer fin is arranged on the lower surface of the heat collecting plate, and the aluminum tube The belt is located under the heat collecting plate, and there are several heat pump working fluid channels on the aluminum tube belt.

A number of fine beads are arranged between the upper glass cover and the lower glass cover, and are bonded and fixed between the upper glass cover and the lower glass cover by glue, thereby increasing the pressure bearing capacity of the glass cover.

The heat collecting plate and the heat transfer tube are welded to minimize the contact thermal resistance between the heat transfer tube and the heat collecting plate; water flows in the heat transfer tube, and the back of the heat collecting plate is connected with an aluminum tube strip, and the aluminum tube The other side of the belt is welded with a heat transfer flat aluminum plate and then connected with heat transfer fins, and the heat pump working fluid flows in the aluminum tube belt.

In the novel pressure-bearing vacuum flat solar collector proposed by the present invention, the vacuum flat plate adopts a double-layer glass cover plate, and some tiny beads are placed between the upper glass plate cover plate and the lower glass plate plate to improve the pressure bearing capacity of the two glass plates. capacity; and the gap between the upper glass cover plate and the lower glass cover plate is evacuated, the main purpose of which is to reduce the convective heat loss of the heat collector plate to the environment through the vacuum between the two plates, and improve the heat collection capacity of the collector Thermal efficiency: the heat collecting plate is integrated with the tube-belt heat exchanger and fins, and a fan is installed on the side of the heat collector. The flat plate heat collector can be used as an evaporator to form a solar-air composite heat source heat pump system. In the absence of solar radiation Or when the solar radiation is very weak, turn on the fan, the flat plate heat exchanger can absorb heat from the air, improve the grade of heat through the heat pump system, and obtain hot water with a higher temperature; set the return air at both ends of the flat plate heat collector Valve, when the fan is not turned on, the inner space of the collector will not communicate with the outside air, which reduces the heat loss of the collector to the outside environment when the solar radiation is strong.

The solar-air composite heat source heat pump water heater shown in Figure 6 can be formed by using the flat plate heat collector. When the solar radiation is strong, the heat pump system does not need to operate, and the flat plate collector and water tank form a separate vacuum flat solar water heater to operate. When the solar radiation is not strong enough, the heat pump system is turned on and the fan is not turned on. The solar radiation heat absorbed by the flat plate collector is absorbed by the heat pump working fluid, and hot water is produced through the heat pump cycle. In winter or rainy days, when there is basically no solar radiation, the water temperature in the system cannot rise due to the inability to absorb solar radiant heat. At this time, the fan and compressor can be turned on, and the heat pump working medium absorbs heat from the air. Through the heat pump compressor, the heat grade is improved through the heat pump cycle, and hot water with a higher temperature can be obtained.

Beneficial effects: the pressurized vacuum flat-plate solar air heat collector can operate as a flat-plate solar heat collector and can also be operated as an evaporator of a heat pump. Its beneficial effect is:

1. The system uses fine glass beads in the glass cover to enhance the pressure bearing capacity of the glass cover and eliminate the disadvantages of ordinary glass that is easy to be broken under pressure after vacuuming.

2. The vacuum flat-plate solar air heat collector can be used as a flat-plate heat collector for solar water heaters when the solar radiation is strong.

3. When the solar radiation is weak, the vacuum flat solar collector works as the evaporator of the solar heat pump to produce hot water efficiently.

4. The vacuum flat solar collector is equipped with a fan and a non-return air valve. When there is no solar radiation, it operates as the evaporator of the heat pump. When the fan is turned on, the refrigerant absorbs heat from the air and obtains a higher temperature through the heat pump cycle. hot water.

The pressurized vacuum flat solar heat collector can effectively reduce radiation and convective heat dissipation to the environment, and the aluminum flat tube strip can effectively improve heat absorption efficiency and can withstand relatively high pressure. The heat collector can be used not only as a common water-based solar heat collector, but also as an evaporator of a solar heat pump. The heat collector is equipped with a fan with a check valve. When there is no solar radiation, air is drawn by the fan for forced convection, and the heat pump working fluid in the flat tube belt can absorb heat from the air.

Description of drawings

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Fig. 1 is a schematic diagram of the appearance of a pressure-bearing vacuum flat panel solar collector of the present invention,

Fig. 2 is the schematic view of the end face of the pressure-bearing vacuum flat panel solar collector of the present invention,

Fig. 3 is a schematic cross-sectional view of A-A of the pressure-bearing vacuum flat panel solar collector of the present invention,

Fig. 4 is the B-B sectional schematic view of the pressurized vacuum flat solar collector of the present invention,

Fig. 5 and Fig. 6 are partial enlarged views of heat exchange tubes and fins of the pressure-bearing vacuum flat solar collector of the present invention,

Fig. 7 is a diagram of a solar-air composite heat source heat pump system composed of a pressurized vacuum flat solar collector of the present invention.

Detailed ways

The pressure-bearing vacuum flat solar collector 18 of the present invention is mainly composed of a glass cover plate 1, an end baffle plate 2, a bottom plate 13, a perfusion fan 3, a side baffle plate 4, a check air valve 6, a bottom insulation layer 12, and a side insulation layer. 14. The heat collecting plate 15, the heat transfer tube 11, the aluminum tube strip 10, and the heat transfer fin 16 are composed. Glass cover plate 1 is made of upper glass cover plate 8, lower glass cover plate 9, bead 7 and sealing strip 5 around. There are several heat pump working fluid passages 17 on the aluminum pipe strip 10 .

The heat loss of the vacuum flat plate collector is mainly concentrated in the heat transfer to the surrounding air through the vacuum glass cover plate 1 . In order to reduce heat transfer. The main measure in this design is to evacuate between the two glass plates, which reduces the heat loss of the heat collecting plate 15 to the environment. The high vacuum may cause the glass cover plate to be broken under pressure. The present invention proposes to arrange a number of small beads 7 between the two glass cover plates, and fix them between the upper glass cover plate 8 and the lower glass cover plate 9 through glue bonding, so that Increase the pressure bearing capacity of the glass cover.

The heat collecting plate 15 is welded to the heat transfer tube 11 to ensure the minimum contact thermal resistance between the heat transfer tube and the heat collecting plate. Water flows in the heat transfer tubes. The back side of the heat collecting plate is welded with an aluminum tube strip 10, and the other side of the aluminum tube strip 10 is welded with a heat transfer fin 16, and the heat pump working medium flows in the aluminum tube strip. The quality of the heat-absorbing coating attached to the heat-absorbing plate of the collector directly affects the performance of the solar water heater. Heat-absorbing coatings can be generally divided into two categories: non-selective coatings and selective coatings. The important index to distinguish their heat-absorbing properties is the ratio α/ε of their absorption ratio α to emission ratio ε. α/ε=1 for non-selective heat-absorbing coatings; α/ε>1 for selective heat-absorbing coatings, and both are selective heat-absorbing coatings. Generally, the larger the ratio, the better the performance. Another important indicator of the heat-absorbing coating is its weather resistance, which is related to the service life of the coating and even the water heater. Selective anodized coating is an ideal coating widely used on flat-plate solar collectors, its α/ε>3, and its service life is about ten years. Considering its heat absorption performance and service life, this design adopts selective anodized coating.

When the solar radiation is strong, the heat pump does not work, and the water flows in the heat transfer tube 11 to absorb the radiant heat absorbed by the heat collector plate 15. After the water temperature rises, it enters the water tank 20 through the water tube 19, and the low-temperature water in the water tank enters the heat transfer tube again. The heat pipe continues to be heated. Such a continuous cycle can obtain hot water at the desired temperature.

When the solar radiation is not strong enough and the water in the water tank 20 only absorbs radiant heat through the heat transfer tube 11 and cannot reach the required temperature, the heat pump compressor 24 can be turned on. At this time, the blower fan 3 may not be turned on, and the solar radiation heat absorbed by the heat collecting plate 15 is transferred to the heat pump working medium. The heat pump working medium becomes gas after being evaporated in the aluminum tube strip 10, enters the heat pump compressor 24, and enters the water tank after being heated and pressurized. The spiral coil 21 releases heat to the water. After the heat pump working medium releases heat in the spiral coil 21 and turns into a liquid, it passes through the connecting pipe 22 and the throttle valve 23 continues to enter the aluminum tube belt 10 to evaporate and absorb the heat collector 15 to absorb. of heat.

When there is no solar radiation in winter or rainy days, water cannot absorb solar radiation through the heat collecting plate 15 . At this point the heat pump compressor 24 can be turned on. At the same time, the fan 3 is turned on, and through the forced convection heat exchange between the heat transfer fins 16 and the air, the heat pump working fluid can efficiently absorb the heat in the air. The compressor 24 enters the spiral coil pipe 21 in the water tank after the temperature rises and pressurizes, and releases heat to the water in the water tank. After the heat pump working medium releases heat in the spiral coil tube 21 and turns into liquid, it passes through the connecting pipe 22 and the throttle valve 23 to continue to evaporate in the aluminum tube belt 10 and absorb heat in the air through the heat transfer fin 16 .

A non-return air valve 6 is arranged at both ends of the flat-plate solar collector, and the non-return air valve only allows air to flow in one direction, and prevents it from flowing in another direction. Usually this kind of valve works automatically. Under the action of fluid pressure flowing in one direction, the valve disc opens; when the fluid flows in the opposite direction, the valve seat is acted on by the fluid pressure and the self-weight of the valve disc to cut off the flow. At the same time, when the swing check valve is fully opened, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small, and the energy consumption of the fan is reduced. The check air valve is closed naturally when the fan is not turned on, and the air in the collector and the air outside the collector will not convect, so the solar radiation heat obtained by the collector plate of the flat collector will not be caused by the air in the collector. Convection with the air outside the collector results in heat loss. When the fan is turned on, under the action of the pressure head of the fan, the non-return air valve will automatically open under the action of the pressure difference.

Claims (3)

1. A pressure-bearing type vacuum flat panel solar collector is characterized in that this collector comprises a glass cover plate (1), an end baffle (2), a base plate (13), a perfusion fan (3), a side baffle (4), non-return air valve (6), bottom insulation layer (12), side insulation layer (14), heat collector plate (15), heat transfer tube (11), aluminum tube strip (10), heat transfer fin sheet (16); wherein: the glass cover plate (1) is composed of an upper glass cover plate (8), a lower glass cover plate (9), and surrounding sealing strips (5); the opposite two end baffles (2) and The two opposite side baffles (4), the glass cover plate (1) and the bottom plate (13) located on the upper and lower sides of the end baffle (2) and the side baffle (4) are co-located to form a whole; the perfusion fan (3) Located on the end baffle (2), the non-return air valve (6) is located on the inner side of the side baffle (4), the bottom insulation layer (12) is located on the bottom plate (13), and the side insulation layer (14) is located on the side Inside the baffle plate (4), a heat collecting plate (15) is arranged on the bottom insulation layer (12), and a heat transfer tube (11) is arranged on the upper surface of the heat collecting plate (15). Heat transfer fins (16) are arranged on the surface, and the aluminum tube strip (10) is located under the heat collecting plate (15), and there are several heat pump working medium passages (17) in the aluminum tube strip (10). 2. The pressurized vacuum flat plate solar collector according to claim 1, characterized in that some beads (7) are set between the upper glass cover (8) and the lower glass cover (9), Bonding and fixing between the upper glass cover plate (8) and the lower glass cover plate (9), thereby increasing the pressure bearing capacity of the glass cover plate. 3. The pressurized vacuum flat panel solar collector according to claim 1, characterized in that the heat collecting plate (15) is welded to the heat transfer tube (11), and the distance between the heat transfer tube and the heat collecting plate is reduced as much as possible. The contact thermal resistance between them; water flows in the heat transfer tube, the back of the heat collector plate is connected to the aluminum tube strip (10), and the other side of the aluminum tube strip (10) is welded with a heat transfer flat aluminum plate and then connected to the heat transfer fins (16), the heat pump working medium flows in the aluminum tube strip.

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