CN104697184B - Phase-change thermal storage type solar water heater - Google Patents

Abstract

The invention relates to a phase-change heat storage solar water heater, which comprises a water inlet pipe, a water outlet pipe and several vacuum pipes. Hollow pipes are arranged inside the several vacuum pipes, and the water inlet and water outlet ends of the hollow pipes are connected with the water inlet pipe and the water outlet respectively. The water outlet pipes are connected, and phase-change heat storage media are respectively arranged in the several vacuum pipes, and the bottom of each vacuum pipe is fixedly connected with an end cover; an exhaust pipe is also included, and the upper parts of the several vacuum pipes are respectively connected to the exhaust pipe through the connecting pipe. The air pipes are connected, and a filter screen is arranged in the connecting pipe, and an exhaust valve is installed on the exhaust pipe; It also includes an overheating protection device. The overheating protection device includes a heat storage pipe, a connecting pipe and a safety valve. ; The inner peripheral wall of the hollow tube has more than one spiral groove. The invention is not only small in volume, capable of secondary heat exchange, but also high in heat exchange efficiency and safety.

Description

Phase change heat storage solar water heater

technical field

The invention relates to a phase change heat storage type solar water heater, which belongs to the technical field of solar energy devices.

Background technique

Existing solar water heaters comprise matching hot water storage tanks and vacuum tubes, and the hot water storage tanks and vacuum tubes are mounted on supports. When the solar water heater is working, the vacuum tube absorbs the heat of the sun's rays, and the heated water flows into the hot water storage tank in the form of thermal convection before use. However, the solar water heater with this structure takes up a lot of space, is inconvenient to install, and only The cold water in the water tank can be heated by a single vacuum tube, the heat exchange efficiency is low, and it is not suitable for cold areas, because in cold areas, solar water heaters are prone to freezing, which will affect the normal operation of solar water heaters in severe cases, and the water flow in the hollow The flow in the tube will generate bubbles on the inner wall of the hollow tube. When there are many bubbles, a layer of air film will be formed at last. The air film has a low density and poor heat transfer, which affects the temperature of the water in the hollow tube and reduces the heat transfer efficiency. Preventing the formation of gas film in the metal tube is crucial to the heat transfer effect of the hollow tube.

Contents of the invention

The object of the present invention is to provide a phase-change thermal storage solar water heater which is not only small in size, but also capable of secondary heat exchange, and has high heat exchange efficiency and safety, so as to overcome the shortcomings of the prior art.

In order to achieve the above object, the technical solution of the present invention is: a phase-change heat storage solar water heater, comprising a water inlet pipe, a water outlet pipe and several vacuum pipes, hollow pipes are arranged in several vacuum pipes, and the water inlet of the hollow pipe Both the water end and the water outlet end extend out of the vacuum tube and communicate with the water inlet pipe and the water outlet pipe respectively, and the water inlet pipe is lower than the water outlet pipe.

a. A phase-change heat storage medium is respectively provided in the plurality of vacuum tubes, and the bottom of each vacuum tube is fixedly connected with an end cover;

b. It also includes an exhaust pipe. The upper parts of several vacuum pipes are respectively connected to the exhaust pipe through connecting pipes, and a filter screen is arranged in the connecting pipe, and an exhaust valve is installed on the exhaust pipe;

c. It also includes an overheating protection device. The overheating protection device includes a heat storage pipe, a connecting pipe and a safety valve. condenser;

d. The inner peripheral wall of the hollow tube has more than one spiral groove.

The phase change heat storage medium is phase change heat storage paraffin.

The water inlet pipe, the water outlet pipe and the hollow pipe are all copper pipes, and the vacuum pipes are stainless steel pipes.

The diameter of the hollow pipe is 8±0.8mm, and the diameters of the water inlet pipe and the water outlet pipe are both 16±0.8mm.

The hollow tube is a U-shaped tube.

The condenser of the heat storage tube is covered on the outer periphery of the heat storage tube.

The positive effects of the present invention are: since several vacuum tubes are equipped with phase-change heat storage mediums, when there is sunlight, the vacuum tubes absorb the heat of solar energy to directly heat the cold water in the hollow tubes, and the phase change The heat storage medium can absorb solar energy and store heat; when there is no sunlight, the phase-change heat storage medium can release heat, and reheat the cold water in the hollow tube to realize secondary heat exchange for the cold water in the hollow tube; and because of this The invention is a flat plate structure, which does not include a hot water storage tank that occupies a large space. Therefore, it not only occupies a small space, but also improves the heat exchange efficiency. Since the bottom of each vacuum tube is fixedly connected with an end cover, it is easy to inject phase change heat storage medium.

Because it also includes an exhaust pipe, the upper parts of several vacuum pipes are respectively connected to the exhaust pipe through connecting pipes, and the lower part of the connecting pipe is provided with a filter screen, and the exhaust port of the exhaust pipe is equipped with an exhaust valve. When the variable heat storage medium absorbs solar energy and stores heat, its volume will become larger, which will cause the pressure in the vacuum tube to also increase. If the pressure in the vacuum tube is too high, the exhaust valve can be opened to decompress, so as to ensure the efficiency of the present invention. safety.

Because it also includes an overheating protection device, the overheating protection device includes a heat storage pipe, a connecting pipe and a safety valve. When the heat is released, if the heat is too large, it will cause the hot water in the outlet pipe to overheat, the safety valve on the connecting pipe will open, the hot water will flow into the heat storage pipe, and the condenser on the heat storage pipe will overheat the hot water. The temperature is lowered, so that the user does not need to control the water temperature, and can adjust itself through the overheating protection device, which improves the safety performance.

Since the inner peripheral wall of the hollow tube has a spiral groove, the water flow will change the flow and move forward under the obstruction of the hollow tube groove, and take away the air bubbles generated by the water flow during the solar heating process, thereby preventing The function of air film formation allows the central water flow to fill the wall to enhance heat absorption, so that the heat absorption reaches the maximum per unit time and improves the heat exchange efficiency.

Description of drawings

Fig. 1 is a structural representation of a specific embodiment of the present invention;

Figure 2 is an enlarged schematic view of part A of Figure 1;

Fig. 3 is a partially enlarged cross-sectional view of the hollow tube in Fig. 1 .

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and given embodiments, but is not limited thereto.

As shown in Figures 1, 2, and 3, a phase-change thermal storage solar water heater includes a water inlet pipe 1, an outlet pipe 2, and several vacuum pipes 3, and hollow pipes 4 are arranged in several vacuum pipes 3. 4 is a U-shaped pipe, the water inlet 4-1 and the water outlet 4-2 of the hollow pipe 4 both extend outside the vacuum tube 3, and communicate with the water inlet 1 and the water outlet 2 respectively, and the water inlet 1 is lower than the water outlet 2. The several vacuum tubes 3 are also provided with a phase-change heat storage medium 5, and the bottom of each vacuum tube 3 is fixedly connected with an end cover 6; an exhaust pipe 7 is also included, and the upper parts of the several vacuum tubes 3 pass through the The connecting pipe 9 communicates with the exhaust pipe 7, and the connecting pipe 9 is provided with a filter screen 10, and the exhaust pipe 7 is equipped with an exhaust valve 8; it also includes an overheating protection device 11, and the overheating protection device 11 includes a heat storage pipe 11 -1, connecting pipe 11-2 and safety valve 11-3, both ends of the heat storage pipe 11-1 are connected to the water outlet pipe 2 through the connecting pipe 11-2, and the connecting pipe 11-2 is equipped with a safety valve 11- 3. The heat storage tube 11-1 is provided with a condenser 11-4; the inner peripheral wall of the hollow tube 4 has more than one spiral groove 4-3.

As shown in FIG. 1 , the phase-change heat storage medium 5 is a phase-change heat storage paraffin, which can increase the temperature of the water in the inner cavity of the hollow tube 4 . But it is not limited to phase change heat storage paraffin, and other heat storage materials such as phase change heat storage balls can also be used.

As shown in Figure 1, the water inlet pipe 1, the water outlet pipe 2 and the hollow pipe 4 are all copper pipes, the vacuum pipe 3 is a stainless steel pipe, and the water inlet pipe 1, the water outlet pipe 2 and the hollow pipe 4 adopt copper pipes because the copper pipes The thermal conductivity of the vacuum tube 3 is strong, and the stainless steel tube is used for the vacuum tube 3 because the stainless steel tube has excellent anti-corrosion performance and can improve the service life of the vacuum tube 3 .

As shown in Figure 1, the diameter of the hollow pipe 4 is 8mm, and the diameters of the water inlet pipe 1 and the water outlet pipe 2 are both 16mm, which can minimize the use area of the present invention and meet the needs of most users.

As shown in Figure 1, since the hollow tube 4 is a U-shaped tube, the heated cold water in the hollow tube 4 flows back and forth, prolonging the heat exchange time, making the heat exchange more sufficient and better Heat exchange effect. Of course, it is not limited thereto, and the hollow pipe 4 may also be a threaded pipe or the like.

A brief description of the use of the present invention is: before use, the bottom of the vacuum tube 3 is filled with a phase-change heat storage medium 5, and is welded to the bottom of the vacuum tube 3 through the end cover 6. When in use, the cold water in the water inlet pipe 1 flows into the hollow pipe 4 for heat exchange, and when there is sunlight, the vacuum pipe 3 absorbs the heat of solar energy to directly heat the cold water in the hollow pipe 4, and the corresponding The heat storage medium 5 can absorb solar energy and store heat; its phase transition point is 56°C, that is, when the temperature reaches 56°C, the phase change heat storage medium 5 starts its phase transition process from solid to liquid, that is, it accumulates heat and starts to melt , and keep its own temperature at 56°C. When external water passes through the hollow tube 4, the water is heated, and it can continuously absorb and store solar heat. When there is no sunlight, the phase-change heat storage medium 5 can release heat, the cold water in the hollow tube 4 is reheated, and the secondary heat exchange of the cold water in the hollow tube is realized, and the heat exchange efficiency is improved; the heated water flows into the outlet pipe 2 through the hollow tube 4, due to this The invention is a flat plate structure, and does not include a hot water storage tank that occupies a large space. Therefore, it occupies a small space. When the phase change heat storage medium 5 releases heat, if the heat is too large, it will cause hot water in the outlet pipe 2 Overheating, the safety valve 11-3 on the connecting pipe 11-2 will open, hot water will flow into the heat storage pipe 11-1, and the condenser 11-4 on the heat storage pipe 11-1 will adjust the temperature of the hot water. Cool down, so that the user does not need to control the water temperature, it can be adjusted by itself through the overheating protection device 11, preventing the safety hazard caused by the overheating of the hot water temperature, and improving the safety performance. Connected, the condenser 11-4 wraps the outer circumference of the heat storage tube 11-1 to improve the cooling efficiency, and the safety valve 11-3 adopts a T/P temperature and pressure safety valve.

Since the inner peripheral wall of the hollow tube 4 has a spiral groove 4-3, the water flow will change and move forward under the hindrance of the groove 4-3 of the hollow tube 4, and the water flow will be heated during the solar heating process. The generated air bubbles are taken away to prevent the formation of the air film, allowing the central water flow to fill the wall to enhance heat absorption, so that the heat absorption per unit time reaches the maximum value, and the heat exchange efficiency is improved.

Since the phase-change heat storage medium 5 absorbs solar energy and stores heat, its volume will increase, which will cause the pressure in the vacuum tube 3 to also increase. If the pressure in the vacuum tube 3 is too high, the exhaust valve 8 can be opened to reduce the pressure. , to ensure the safety of the present invention, so that the safety is high, and the bottom of the connecting pipe 9 is provided with a filter screen 10, which can effectively prevent the phase-change heat storage medium 5 from flowing into the exhaust pipe 7.

Claims (6)

1. A phase-change thermal storage solar water heater, comprising a water inlet pipe (1), an outlet pipe (2) and several vacuum pipes (3), and hollow pipes (4) are arranged inside the several vacuum pipes (3). The water inlet end (4-1) and the water outlet end (4-2) of the empty pipe (4) all extend out of the vacuum pipe (3), and communicate with the water inlet pipe (1) and the water outlet pipe (2) respectively, and the water inlet pipe (1) lower than the outlet pipe (2), characterized in that: a. The plurality of vacuum tubes (3) are respectively provided with a phase-change heat storage medium (5), and the bottom of each vacuum tube (3) is fixedly connected with an end cover (6); b. It also includes an exhaust pipe (7), the upper parts of several vacuum pipes (3) are respectively connected to the exhaust pipe (7) through the connecting pipe (9), and the connecting pipe (9) is equipped with a filter screen (10) , the exhaust pipe (7) is equipped with an exhaust valve (8); c. It also includes an overheating protection device (11). The overheating protection device (11) includes a heat storage pipe (11-1), a connecting pipe (11-2) and a safety valve (11-3), and the heat storage pipe (11-1) Both ends are connected to the outlet pipe (2) through the connecting pipe (11-2), and the connecting pipe (11-2) is equipped with a safety valve (11-3), and the heat storage pipe (11-1) is equipped with a condensation device (11-4); d. The inner peripheral wall of the hollow tube (4) has more than one spiral groove (4-3). 2. The phase change heat storage solar water heater according to claim 1, characterized in that: the phase change heat storage medium (5) is phase change heat storage paraffin. 3. The phase-change heat storage solar water heater according to claim 1, characterized in that: the water inlet pipe (1), the water outlet pipe (2) and the hollow pipe (4) are all copper pipes, and the vacuum pipe (3) For stainless steel tubes. 4. The phase change heat storage solar water heater according to claim 1, characterized in that: the diameter of the hollow pipe (4) is 8±0.8mm, the diameter of the water inlet pipe (1) and the water outlet pipe (2) Both are 16±0.8mm. 5. The phase change thermal storage solar water heater according to claim 1, characterized in that: the hollow tube (4) is a U-shaped tube. 6. The phase-change heat storage solar water heater according to claim 1, characterized in that: the condenser (11-4) of the heat storage pipe (11-1) is wrapped around the outer periphery of the heat storage pipe (11-1).