Through heat collecting pipe type solar water heater

Abstract

The utility model relates to a through heat collecting pipe type solar water heater, which is characterized in that hot air generated by a through heat collecting pipe type solar air heater is directly mixed with feed water in a washing tower for heating, and meanwhile, a heat storage process is adopted, so that efficient utilization of solar heat is realized; the problem of incrustation in a solar water heater in which an existing heat collector directly heats water is solved, the technological process is simplified, installation and maintenance are convenient, the operation cost is low, and expected social and economic benefits are remarkable.

Description

TECHNICAL FIELD

[0001] The utility model relates to solar water heater technical field especially relates to a kind of solar water heater using through heat pipe supply hot air heating water. BACKGROUND

[0002] Solar heat utilization application form includes solar hot water supply, solar heating, solar refrigeration, solar industrial and agricultural application, photovoltaic and photothermal integration (PV / T) application etc. According to the statistical data of IEA SHC TCP, from the system installed capacity, in 2022, the installed capacity of household solar heat utilization system for providing domestic hot water or heating for single-family house accounts for about 60% of the total installed capacity of global solar heat utilization system.

[0003] Taking China as an example, the annual newly added collector area and proportion of different types of solar collectors from 2004 to 2023 are as follows: Figure 2 As shown in the table.

[0004] The solar heat utilization system using the above-mentioned collector, especially for single-family house, takes the circulating hot water system as the main application type, and the existing problem is that the collector is easy to scale and difficult to handle, which is difficult to eliminate from the source. Chinese patents such as 202110572786.4 - a new energy solar water heater scale cleaning device, 202222951988.2 - a solar water heater with built-in scale scraping and cleaning structure, 202321328920.7 - a solar water heater water tank with purification function, 202321565698.2 - a solar water heater convenient for cleaning scale, etc. provide measures to clean scale, which has a certain effect, but after removing scale for a period of time, scaling will appear again.

[0005] Chinese patents such as 202221467099.2 - a solar double-pass heat pipe type balcony water heater, realize airflow heating through the cooperation of header tank and solar heat collector pipe, set heat exchanger on the circulating pipe connected at the head and tail of header tank, connect heat exchanger and water tank, set circulating pump on water tank and fan on circulating pipe, the power of fan and circulating pump is all supplied by solar photovoltaic panel set outdoors, it has less overall connection points and leakage points, realizes continuous heating of liquid through circulating pump, can continuously maintain the temperature of water tank and realize continuous supply of hot water, eliminates the scaling problem of traditional water heating type collector, which is an excellent technical scheme. But it also has some problems: there is still scaling on the water side of gas-water heat exchanger, which affects the heat exchange effect.

[0006] Therefore, how to solve the scaling problem of water heating type collector and heat exchanger, optimize the equipment setting of solar water heater under the condition of safe and efficient heat transfer, is worth further studying. SUMMARY

[0007] The purpose of this invention is to solve the above-mentioned problems. It utilizes a through-type heat collection tube to generate hot air, which is then used as a heat source to directly mix with the water in the washing tower for heat and moisture exchange. This efficiently produces hot water while eliminating the problem of scale buildup in traditional water heating type heat collection tubes. Furthermore, the process equipment is simplified, safe to use, requires less investment, and is convenient to maintain and manage, making it highly economical.

[0008] A type of through-tube solar water heater, as shown in the attached image. Figure 1 As shown, the through-tube solar water heater includes a solar hot air blower 7, a washing tower 11, and a hot water tank 1. The solar hot air blower 7 includes a left connecting box 8, a right connecting box 9, and through-tube solar collectors 10. Several through-tube solar collectors 10 are arranged between the left connecting box 8 and the right connecting box 9. Hot air drawn from the left connecting box 8 is sent to the washing tower 11 by a fan 13 to heat the water supplied by the water supply line 23 and perform gas-water separation. The separated gas returns to the right connecting box 9 of the solar hot air blower 7 through the return air pipe 5, and then absorbs solar heat energy through the through-tube solar collectors 10 before entering the left connecting box 8, thus forming a closed-loop air circulation loop of the through-tube solar water heater. The separated water falls into the hot water tank 1, and the water in the hot water tank 1 is then transported to the washing tower 11 by a circulating water pump 22 and a water supply line 23.

[0009] Alternatively, hot air drawn from the left connecting box 8 can be sent to the scrubbing tower 11 via a specific pipeline to heat the water supplied by the water supply pipeline 23 and perform gas-water separation. The separated gas returns to the right connecting box 9 of the solar hot air heater 7 via the circulating fan 4 and the return air duct 5, and then absorbs solar energy through the through-collector tube 10 before entering the left connecting box 8, thus forming a closed-loop air circulation loop for the through-collector tube solar water heater. The separated water falls into the hot water tank 1, and the water in the hot water tank 1 is then transported to the scrubbing tower 11 via the circulating water pump 22 and the water supply pipeline 23. The aforementioned specific pipeline is the hot air pipeline 15, which is used to send the hot air drawn from the left connecting box 8 into the scrubbing tower 11 via the specific pipeline.

[0010] The scrubbing tower 11 includes a shell, end caps, packing support 111, packing 112, demister layer 113, support rod 114, and connecting pipes, similar to the structure of scrubbing towers widely used in industry. Its essence is a heat exchanger that directly contacts gas and water. The scrubbing tower 11 can also be integrated with the hot water tank 1, serving as a gas-water mixing and separation element for the hot water tank 1.

[0011] The solar hot air heater 7 or the through-collector tube 10 can be used in multiple sets in series, parallel or series-parallel configurations. For example, when the solar hot air heater 7 is used in series, the outlet air of the left connecting box 8 of one set of solar hot air heater 7 is used as the inlet air of the right connecting box 9 of another set of solar hot air heaters, thereby effectively increasing the temperature of the output air.

[0012] Preferably, the through heat collecting tube adopts a vacuum heat collector, the inner layer of the heat collecting tube is a stainless steel tube, the outer layer is a glass tube plus metal corrugated tubes at both ends, and the outer surface of the inner tube is coated with a selective absorption coating to achieve maximum absorption of direct solar radiation and minimum infrared wave re-radiation.

[0013] The circulating fan 4 is provided with an adjusting damper 3 for adjusting the air supply of the circulating fan 4.

[0014] The ventilator 13 is provided with a hot air adjusting damper 12 for adjusting the air supply of the ventilator 13.

[0015] The circulating fan 4 and the ventilator 13 are substantially the same, only for distinction.

[0016] The circulating fan 4 or the ventilator 13 adopts a centrifugal, axial, screw or vortex fan.

[0017] The solar hot air generator 7 is provided with necessary support rods or support frames to safely, stably and effectively fix the solar hot air generator, avoiding tipping accidents caused by strong winds and the like.

[0018] The hot water tank 1 is provided with a water inlet valve 17, cold water 16 enters the hot water tank 1 through the water inlet valve 17, and the cold water 16 adopts tap water or underground water.

[0019] Preferably, the water inlet valve 17 is an automatic water replenishment valve, which is opened to replenish water when the water level in the hot water tank 1 is at a set low water level, and is closed to stop replenishing water when the water level in the hot water tank 1 reaches a set high water level, thereby avoiding the phenomenon of overflow and waste of the water tank of a traditional solar water heater due to forgetting to close the water inlet valve when replenishing water.

[0020] The hot water tank 1 is provided with a hot water valve 19: the water in the hot water tank 1 is output as hot water 20 for daily use through the hot water valve 19.

[0021] The hot water tank 1 is provided with a blowdown valve 18 for discharging solid pollutants precipitated in the hot water tank 1.

[0022] The hot water tank 1 is provided with an air inlet valve 24: the air inlet valve 24 is in a closed state when the through heat collecting tube type solar water heater is running, and can be opened to replenish air when the air in the air space in the hot water tank 1 is lower than the atmospheric pressure, such as indicated by a pressure gauge installed on the hot water tank 1, and is closed when the pressure is balanced with the outside, thereby avoiding the phenomenon of "negative pressure suction" of the hot water tank due to air dissolving into water.

[0023] When the hot water tank 1 operates in a positive pressure mode, a small amount of air will dissolve into water and be carried out by hot water, which can be replenished through an air compressor, an air cylinder or an air pump through the air inlet valve 24.

[0024] The heat exchanger 27 and the heat accumulator 28 are provided: the hot air from the left header tank 8 is sent into the right header tank 9 of the solar air heater 7 through the ventilator 13, the heat accumulator pipeline valve 26, the heat exchanger 27, the high-temperature heat accumulator pipeline 30, absorbs the heat energy of the sun through the through-penetration heat collection pipe 10, and enters the left header tank 8, thereby forming a heat storage air closed loop circulation loop; the heat carrier medium enters the heat exchanger 27 to absorb heat through the booster 29, returns to the heat accumulator 28 to store heat, and the heat carrier medium returns to the booster 29, thereby forming a heat carrier and heat storage circulation loop of the heat carrier medium.

[0025] The booster 29 is a hydraulic pump when the heat carrier medium is a liquid (for example, heat-conducting oil), and is a gas compressor when the heat carrier medium is a gas.

[0026] The heat accumulator 28 adopts liquid heat storage (such as heat-conducting oil), solid heat storage (such as pebbles), or phase change heat storage.

[0027] When the heat accumulator 28 adopts liquid heat storage, the heat carrier medium is the heat storage liquid, and when heating, the heat carrier medium 35 can be output through the booster 29 and the heat carrier medium valve 34 to supply heat and then return to the heat accumulator 28, or the heat carrier medium can pass through the booster 29 and the heat exchanger 27 and then return to the heat accumulator 28 to indirectly supply heat by using the heat exchanger 27.

[0028] When the heat accumulator 28 adopts phase change or solid heat storage, the air 31 is output through the heat accumulator 28 and the air blower 32 to output the heat supply air 33.

[0029] When the heat accumulator 28 adopts phase change heat storage, the phase change heat storage material adopts Na2CO3-BaCO3 / MgO or Na2SO4 / SiO2.

[0030] The circulation fan 4 or the ventilator 13 adopts a variable frequency speed regulation operation mode, and when the sunlight, heating, and water temperature of the hot water tank change, the air supply amount and the air supply pressure can be flexibly adjusted.

[0031] Preferably, the hot water tank 1 adopts a corrosion-resistant stainless steel material.

[0032] The left and right of the left header tank 8 and the right header tank 9 are only for distinction and do not limit the orientation, for example, they can also be replaced by upper and lower.

[0033] The hot water tank 1, the washing tower 11, the air pipeline, and the heat accumulator 28 of the through-penetration heat collection pipe type solar water heater adopt heat preservation measures.

[0034] The through-penetration heat collection pipe type solar water heater is provided with an electric heater or a gas waste heat heat recovery device, which is used as a supplementary heat source to heat water on cloudy days.

[0035] The application is also applicable to nitrogen, argon, or a mixed gas composed of oxygen and nitrogen.

[0036] The pipeline, instrument, valve, adjustment bypass, etc. not mentioned in the application refer to the mature technology in the known solar water heating project.

[0037] The part not mentioned in the application, such as safety accessories, interlocking protection device and automatic control, etc. is matched by the existing known technology.

[0038] Compared with the prior art, the utility model has the following advantages:

[0039] 1. Compared with the prior art of the solar water heater technology of directly heating water by the heat collecting pipe, since the clean air that is washed by water and closed-circuit circulated passes through the through heat collecting pipe, the through heat collecting pipe is clean and has high heat transfer efficiency, unlike the heat collecting pipe that directly heats water, which is blocked by scale and affects the heat transfer effect, so that the maintenance cost is extremely low, and the operation cycle is greatly prolonged; in winter, unlike the heat collecting pipe that directly heats water, which is blocked by ice due to low temperature, and the connecting part of the heat collecting water tank and the heat collecting pipe is cracked and leaks, etc.

[0040] 2. Compared with the prior art of the through heat collecting pipe heating air to produce hot water technology (for example, 202221467099.2-a solar double-through heat collecting pipe type balcony water heater), the application does not have the scaling problem of the water side of the air-water heat exchanger, adopts the hot air generated by the solar hot air generator to directly mix and heat with the water supply of the washing tower, separates air and water, and has a clean air closed-circuit circulation heat recovery process, which has high heat transfer efficiency, and the scale and dregs generated during heating are difficult to form large blocks due to the disturbance of the heated air, and are easily discharged through the blowdown valve, so that the heat recovery efficiency is high.

[0041] 3. Compared with the prior art of the solar water heater technology of directly heating water by the heat collecting pipe, the hot water tank and the fan of the application are arranged in the room, so that the installation, use and maintenance are convenient, and the operation cost is low.

[0042] 4. Compared with the prior art of the solar water heater technology of directly heating water by the heat collecting pipe, the application can be arranged on the roof or used as a household balcony type wall-mounted solar water heater: when arranged on the roof, the weight is light, there is no water leakage, and the damage to the waterproof layer of the roof is extremely light, so that the safety factor is high; when used as a household balcony type wall-mounted solar water heater, the weight is light, there is no water leakage, and the influence on the downstairs residents and pedestrians caused by water leakage is avoided.

[0043] 5. Compared with the prior art of the heat collecting pipe type solar water heater, the application is provided with a high-temperature heat storage and heat supply heat accumulator system, so that the high-temperature heat utilization of solar heat is realized. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 It is a process flow schematic diagram of a through heat collecting pipe type solar water heater of the utility model.

[0045] Figure 1 In the middle: 1-Hot water tank, 2-Gas space, 3-Regulating damper, 4-Circulating fan, 5-Return air duct, 6-One-way valve, 7-Solar hot air heater, 8-Left connector, 9-Right connector, 10-Through collector tube, 11-Scrubber tower, 111-Packing support, 112-Packing, 113-Defogger layer, 114-Support rod, 115-Return pipeline (overflow pipe), 12-Hot air regulating damper, 13-Ventilator, 14-Hot air duct valve, 15- -Hot air duct, 16-Cold water, 17-Inlet valve, 18-Drain valve, 19-Hot water valve, 20-Hot water, 21-Regulating valve, 22-Circulating water pump, 23-Water supply pipeline, 24-Air inlet valve, 25-Regulating valve, 26-Heat storage pipeline valve, 27-Heat exchanger, 28-Heat accumulator, 29-Booster, 30-High temperature heat storage pipeline, 31-Air, 32-Blower, 33-Heating air, 34-Heat medium valve, 35-Heating medium.

[0046] Figure 2 This is a chart showing the annual increase in collector area and percentage of different types of solar collectors in China from 2004 to 2023. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Example 1

[0048] As attached Figure 1 As shown, the through-tube solar water heater includes a solar hot air blower 7, a washing tower 11, and a hot water tank 1. The solar hot air blower 7 includes a left connecting box 8, a right connecting box 9, and through-tube solar collectors 10. Several through-tube solar collectors 10 are arranged between the left connecting box 8 and the right connecting box 9. Hot air drawn from the left connecting box 8 is sent into the washing tower 11 by a fan 13. The water supplied by the water supply pipeline 23 is heated by the packing 112 and separated into gas and water by the demisting layer 113. The separated gas returns to the right connecting box 9 of the solar hot air blower 7 through the return air pipe 5, and then absorbs solar energy through the through-tube solar collectors 10 before entering the left connecting box 8, thus forming a closed-loop air circulation loop of the through-tube solar water heater. The separated water returns to the hot water tank 1 through the return pipeline 115. The water in the hot water tank 1 is then transported to the washing tower 11 by the regulating valve 21, the circulating water pump 22, and the water supply pipeline 23.

[0049] Or from the left box 8 out of hot air through the hot air duct 15 into the washing tower 11, heating by water supply line 23 to the water and through the mist layer 113 gas water separation, separation of the gas through the circulating fan 4, return air duct 5 back to the right box 9 of the solar air heater 7, again through the through collector tube 10 to absorb the heat of solar energy, into the left box 8, thus forming a through collector tube type solar water heater air closed loop circulation, separated water through the return line 115 back to the hot water tank 1, the water in the hot water tank 1 is again adjusted through the valve 21, circulating water pump 22, water supply line 32 to the washing tower 11.

[0050] The washing tower 11 includes a shell, head, packing support 111, packing 112, mist layer 113, washing tower 11 support rod 114 and connecting pipe, similar to the widely used in industry washing tower structure, which is essentially a gas water direct contact heat exchanger.

[0051] The solar air heater 7 or through collector 10 can be used in multiple groups in series, parallel or series parallel, such as solar air heater 7 in series: a group of solar air heater 7 left box 8 outlet air, as another group of solar air heater right box 9 of the import air, thereby effectively increasing the temperature of the output air.

[0052] Preferably, the through collector tube uses a vacuum collector, the inner layer of the collector tube is a stainless steel tube, the outer layer is a glass tube plus two end metal bellows, the outer surface of the inner tube is coated with a selective absorption coating to achieve the maximum absorption of solar direct radiation and the minimum infrared wave re-emission.

[0053] The circulating fan 4 is provided with an adjusting damper 3 for adjusting the air supply of the circulating fan 4.

[0054] The ventilator 13 is provided with a hot air measuring adjusting damper 12 for adjusting the air supply of the ventilator 13.

[0055] The circulating fan 4 or ventilator 13 uses a centrifugal, axial, screw or vortex fan.

[0056] The solar air heater 7 is provided with necessary support rods or support frames to safely, stably and effectively fix the solar air heater, avoiding tipping accidents caused by strong winds and the like.

[0057] The hot water tank 1 is provided with a water inlet valve 17, and cold water 16 enters the hot water tank 1 through the water inlet valve 17, and the cold water 16 uses tap water or underground water.

[0058] Preferably, the water inlet valve 17 is an automatic water replenishment valve, which opens when the water level in the hot water tank 1 reaches a set low water level, and closes when the water level reaches a set high water level, thereby avoiding the waste of water overflow caused by forgetting to close the water inlet valve when replenishing water in a conventional solar water heater.

[0059] The hot water tank 1 is provided with a hot water valve 19, through which hot water in the hot water tank 1 is output as hot water for daily use 20.

[0060] The hot water tank 1 is provided with a drain valve 18 for discharging solid waste deposited in the hot water tank 1.

[0061] The hot water tank 1 is provided with an air inlet valve 24, which is closed during operation of the through-pipe solar water heater, and is opened when the air pressure in the air space of the hot water tank 1 is lower than the atmospheric pressure, as indicated by a pressure gauge installed on the hot water tank 1, and is closed when the air pressure is balanced with the external pressure, thereby avoiding the phenomenon of "negative pressure collapse" of the hot water tank caused by air dissolving into water.

[0062] When the hot water tank 1 operates in a positive pressure mode, a small amount of air may dissolve into water and be carried out by hot water, which can be replenished through the air inlet valve 24 by an air compressor, an air cylinder, or a pump.

[0063] The heat exchanger 27 and the heat accumulator 28 are provided: hot air from the left header tank 8 is sent to the right header tank 9 of the solar air heater 7 through the air blower 13, the heat accumulator valve 26, the heat exchanger 27, and the high-temperature heat accumulator line, absorbs solar heat through the through-pipe collector 10, and enters the left header tank 8, thereby forming a closed loop circulation circuit of heat storage air; the heat carrier medium enters the heat exchanger 27 through the booster 29 to absorb heat, returns to the heat accumulator 28 to store heat, and then returns to the booster 29, thereby forming a heat carrier and heat storage circulation circuit of the heat carrier medium.

[0064] The booster 29 is a hydraulic pump when the heat carrier medium is a liquid (such as heat-conducting oil), and is a gas compressor when the heat carrier medium is a gas.

[0065] The heat accumulator 28 adopts liquid heat storage (such as heat-conducting oil), solid heat storage (such as pebbles), or phase change heat storage.

[0066] When the heat accumulator 28 adopts liquid heat storage, the heat carrier medium is the heat storage liquid, which can be output as a heat supply medium 35 through the booster 29 and the heat carrier medium valve 34 for heat supply and then returned to the heat accumulator 28, or can pass through the booster 29 and the heat exchanger 27 and then return to the heat accumulator 28 for indirect heat supply.

[0067] When the heat accumulator 28 adopts phase change or solid heat storage, the air 31 is outputted through the heat accumulator 28 and the air blower 32 to supply the heat air 33.

[0068] When the heat accumulator 28 adopts phase change heat storage, the phase change heat storage material adopts Na2CO3-BaCO3 / MgO or Na2SO4 / SiO2.

[0069] The circulating fan 4 or the ventilator 13 adopts variable frequency speed regulation operation mode, and when the sunlight, heat supply and water temperature of the hot water tank change, the air supply amount and air supply pressure are flexibly adjusted.

[0070] Preferably, the hot water tank 1 adopts corrosion-resistant stainless steel material.

[0071] The hot water tank 1, the washing tower 11, the air pipeline and the heat accumulator 28 of the through heat collecting pipe type solar water heater take heat preservation measures.

[0072] The hot water tank 1 is provided with an electric heater or a gas waste heat heat recovery device, which is used for heating water as a supplementary heat source on cloudy days.

[0073] The present application is also applicable to nitrogen, argon or a mixture of oxygen and nitrogen.

[0074] The pipelines, instruments, valves, adjustment bypasses and the like not mentioned in the present application are matched with the mature technology in the known solar water heating engineering.

[0075] The parts not mentioned in the present application such as safety accessories, interlocking protection devices and automatic control are matched with the existing known technology. Although the present application has disclosed the above-mentioned preferred embodiments, they are not used to limit the present application, and any person skilled in the art can make various changes or modifications without departing from the spirit and scope of the present application, and the changes or modifications also belong to the protection scope of the present application. Therefore, the protection scope of the present application should be defined by the claims of the present application.

Claims

1. A through-tube solar water heater, characterized in that, The through-collector solar water heater includes a solar hot air blower (7), a washing tower (11), and a hot water tank (1). The solar hot air blower (7) includes a left connecting box (8), a right connecting box (9), and through-collector tubes (10). Several through-collector tubes (10) are arranged between the left connecting box (8) and the right connecting box (9). Hot air drawn from the left connecting box (8) is sent to the washing tower (11) by a fan (13) to heat the water supplied by the water supply line (23) and perform gas-water separation. The separated gas returns to the right connecting box (9) of the solar hot air blower (7) through the return air pipe (5), and then absorbs the heat energy of the solar energy through the through-collector tubes (10) and enters the left connecting box (8). The separated water falls into the hot water tank (1). The water in the hot water tank (1) is then transported to the washing tower (11) by a circulating water pump (22) and a water supply line (23). Alternatively, hot air drawn from the left connecting box (8) is sent to the scrubbing tower (11) via the hot air pipeline (15) to heat the water supplied by the water supply pipeline (23) and perform gas-water separation. The separated gas is returned to the right connecting box (9) of the solar hot air generator (7) via the circulating fan (4) and return air pipeline (5), and then absorbs the solar energy through the through heat collection pipe (10) and enters the left connecting box (8). The separated water falls into the hot water tank (1), and the water in the hot water tank (1) is then transported to the scrubbing tower (11) via the circulating water pump (22) and water supply pipeline (23).

2. The through-tube solar water heater according to claim 1, characterized in that, The circulating fan (4) or ventilation fan (13) mentioned above is a centrifugal, axial, screw or vortex fan.

3. The through-tube solar water heater according to claim 1, characterized in that, The hot water tank (1) is equipped with an inlet valve (17): cold water (16) enters the hot water tank (1) through the inlet valve (17); The inlet valve (17) is an automatic water supply valve. When the water level in the hot water tank (1) is at the set low water level, the automatic water supply valve opens to supply water. When the water level in the hot water tank (1) reaches the set high water level, the automatic water supply valve closes and stops supplying water.

4. The through-tube solar water heater according to claim 1, characterized in that, A heat exchanger (27) and a heat storage device (28) are provided: hot air drawn from the left connecting box (8) is sent to the right connecting box (9) of the solar hot air heater (7) via a fan (13), a heat storage pipeline valve (26), a heat exchanger (27), and a high-temperature heat storage pipeline (30), and then absorbs the heat energy of the solar energy through the through heat collection pipe (10) and enters the left connecting box (8); the heat transfer medium enters the heat exchanger (27) through the booster (29) to absorb heat and returns to the heat storage device (28), and the heat transfer medium returns to the booster (29).

5. The through-tube solar water heater according to claim 4, characterized in that, The heat storage device (28) adopts liquid heat storage, solid heat storage or phase change heat storage.

6. The through-tube solar water heater according to claim 5, characterized in that, When the heat storage device (28) adopts the phase change heat storage method, the phase change heat storage material is Na2CO3-BaCO3 / MgO or Na2SO4 / SiO2.

7. The through-tube solar water heater according to claim 1, characterized in that, The circulating fan (4) or ventilation fan (13) adopts a variable frequency speed regulation operation mode.

8. The through-tube solar water heater according to claim 1, characterized in that, The through-tube solar water heater is equipped with an electric heater or a gas waste heat recovery unit.

9. The through-tube solar water heater according to claim 1, characterized in that, The inner layer of the through-type heat collection tube (10) is a stainless steel tube, and the outer layer is a glass tube with metal corrugated tubes at both ends. The outer surface of the inner tube is coated with a selective absorption coating.

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