A layered cylindrical triple-spiral tube phase change thermal storage with electric heating

Abstract

The application discloses a layered cylindrical three-spiral tube type phase change heat accumulator with electric heating, which mainly comprises a hot fluid inlet pipe, a valve 1, a valve 2, a cold fluid outlet pipe, an upper end face, a shell, phase change material 1, three-spiral heat exchange pipes, a heat insulation baffle, phase change material 2, a cold fluid inlet pipe, a valve 3, a hot fluid outlet pipe, a valve 4, a lower end face, a tubular electric heater, a heat exchange central pipe and a spiral electric heater. The heat insulation baffle divides the whole shell into two layers, the upper layer and the lower layer of the shell are respectively filled with different phase change heat storage materials, and the utilization rate of the phase change materials is increased. Through optimization of the arrangement of the heat exchange pipes and the shell, the three-spiral heat exchange pipes and the heat exchange central pipe can increase the heat exchange area and be beneficial to heat transfer, so that the performance of the heat storage device is improved. The electric heater assists heat storage, the heat storage medium in the heat storage tank is heated by using cheap off-peak electricity at night, heat storage is realized, different heating equipment such as solar energy and low-price valley electricity can be connected, and the use requirement under different working conditions can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of phase change heat storage, in particular to a phase change heat storage device used in heat storage process, and more particularly to a layered cylindrical three-spiral pipe type phase change heat accumulator with electric heating. BACKGROUND

[0002] With the sustained high-speed growth of the national economy in recent years, the demand for energy in China is growing, in order to reduce the impact of fossil energy pollutants on the ecological environment, the development and utilization of renewable energy has become a new research hotspot in the field of energy, among the development of renewable energy, solar energy and industrial waste heat recovery grow faster, both of which need to solve the problems of heat dispersion, poor energy continuity and stability in the process of heat utilization. The heat storage technology can convert discontinuous and incoherent heat energy into stable energy output, which can improve the efficiency of energy recycling, and the phase change heat accumulator is an essential device for the application of phase change energy storage technology in actual heat storage process. SUMMARY

[0003] In order to overcome the problems of low heat utilization rate of phase change material, large temperature difference of phase change material heat exchange, and uneven overall temperature of the existing phase change heat accumulator, the present application provides a layered cylindrical three-spiral pipe type phase change heat accumulator with electric heating. The shell is divided into two layers by a heat insulation baffle, the upper layer and the lower layer of the shell are respectively filled with different phase change heat storage materials, the melting point of the phase change heat storage material filled in the upper layer of the shell is greater than that of the phase change heat storage material filled in the lower layer of the shell, and the temperature of the hot fluid gradually decreases from the inlet to the outlet, which can effectively avoid the waste of phase change material caused by the failure of phase change material to melt due to the decrease of fluid temperature, avoid the phenomenon that the phase change material at the inlet is overheated and the outlet is not melted, increase the utilization rate of phase change material, and reduce the heat loss.

[0004] The present application is realized by the following technical solutions:

[0005] The application discloses a kind of charged heating hierarchical cylindrical three spiral pipe type phase change heat accumulator, it is characterized in that, including: hot fluid inlet pipe, valve 1, valve 2, cold fluid outlet pipe, upper end face, shell, phase change material 1, three spiral heat exchange tube, heat insulation baffle, phase change material 2, cold fluid inlet pipe, valve 3, hot fluid outlet pipe, valve 4, lower end face, tubular electric heater, heat exchange center tube, spiral electric heater.Shell both ends are welded upper end face and lower end face respectively, hot fluid inlet pipe and cold fluid outlet pipe are located in upper end face, hot fluid outlet pipe and cold fluid inlet pipe are located in lower end face.Heat exchange tube bundle is three spiral heat exchange tube and a heat exchange center tube with upper half portion being straight pipe and lower half portion being spiral pipe, the pipe diameter of three spiral heat exchange tube is less than hot fluid inlet pipe.The three spiral heat exchange tube and heat exchange center tube are located between upper and lower end faces, three spiral heat exchange tube and heat exchange center tube are arranged in parallel.The heat exchange center tube is straight pipe in shell upper layer, is spiral pipe in shell lower layer, and the diameter of upper layer straight pipe is greater than the diameter of lower layer spiral pipe, and heat exchange center tube is straight pipe in shell upper layer, is spiral pipe in shell lower layer.The center heat exchange tube has spiral electric heater around straight pipe in shell upper layer, and heat exchange center tube has a tubular electric heater in the middle of spiral pipe in shell lower layer.The hot fluid inlet pipe, cold fluid outlet pipe, cold fluid inlet pipe and hot fluid outlet pipe are all provided with valve, and the flow direction of cold and hot fluid is controlled.The shell is cylindrical, and the shell is provided with heat preservation material outside.

[0006] The application has simple structure, and the existence of three spiral heat exchange tube and heat exchange center tube can increase heat exchange area, is favorable for heat transfer, and ensures that heat is evenly distributed.The heat insulation baffle divides the whole shell into upper and lower layers, the upper layer and the lower layer of the shell are filled with different phase change heat storage materials, the melting point of the phase change heat storage material filled in the upper part of the shell is greater than the melting point of the phase change heat storage material filled in the lower part of the shell, the temperature of hot fluid gradually decreases from the inlet to the outlet, which can effectively avoid the waste of phase change material caused by the failure of phase change material to melt due to the decrease of fluid temperature, avoid the phenomenon that the phase change material at the inlet is overheated and the phase change material at the outlet has not melted, increase the utilization rate of phase change material, and thus reduce heat loss.The upper half portion of the heat exchange center tube has spiral electric heater around straight pipe, and the lower half portion of the center heat exchange tube has a tubular electric heater in the middle of spiral pipe, which can directly provide heat by electric heating, and can meet the needs in various working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 It is a structure diagram of the hierarchical cylindrical three spiral pipe type phase change heat accumulator with electric heating according to the application.

[0008] Figure 2 It is a schematic diagram of three spiral heat exchange tube of the hierarchical cylindrical three spiral pipe type phase change heat accumulator with electric heating according to the application.

[0009] Figure 3is a schematic diagram of a heat exchange center tube of a charged heating hierarchical cylindrical three spiral pipe type phase change heat accumulator according to the present application.

[0010] Figure 4 is a schematic diagram of a pipe type and spiral type electric heater of a charged heating hierarchical cylindrical three spiral pipe type phase change heat accumulator according to the present application DETAILED DESCRIPTION

[0011] In order to better understand the present application, the present application is further described below in conjunction with the accompanying drawings.

[0012] A charged heating hierarchical cylindrical three spiral pipe type phase change heat accumulator, characterized in that it comprises a hot fluid inlet pipe, a valve 1, a valve 2, a cold fluid outlet pipe, an upper end face, a shell, a phase change material 1, a three spiral heat exchange pipe, a heat insulation baffle, a phase change material 2, a cold fluid inlet pipe, a valve 3, a hot fluid outlet pipe, a valve 4, a lower end face, a pipe type electric heater, a heat exchange center tube, and a spiral type electric heater. The shell is welded with the upper end face and the lower end face at both ends, and the hot fluid inlet pipe and the cold fluid outlet pipe are located at the upper end face, and the hot fluid outlet pipe and the cold fluid inlet pipe are located at the lower end face. The heat exchange tube bundle is a three spiral heat exchange pipe and a heat exchange center tube with an upper half straight pipe and a lower half spiral pipe, and the pipe diameter of the three spiral heat exchange pipe is smaller than that of the hot fluid inlet pipe. The three spiral heat exchange pipe and the heat exchange center tube are located between the upper and lower end faces, and the three spiral heat exchange pipe and the heat exchange center tube are arranged in parallel. The heat exchange center tube is a straight pipe in the upper layer of the shell and a spiral pipe in the lower layer of the shell, and the diameter of the upper layer straight pipe is larger than that of the lower layer spiral pipe. The center heat exchange tube is a straight pipe in the upper layer of the shell and a spiral pipe in the lower layer of the shell. The center heat exchange tube is provided with a spiral type electric heater around the straight pipe in the upper layer of the shell, and the heat exchange center tube is provided with a pipe type electric heater in the middle of the spiral pipe in the lower layer of the shell. The hot fluid inlet pipe, the cold fluid outlet pipe, the cold fluid inlet pipe and the hot fluid outlet pipe are all provided with valves to control the flow direction of the cold and hot fluids. The shell is cylindrical, and the shell is provided with a heat preservation material outside.

[0013] When melting and storing heat, high-temperature heat fluid enters the three spiral heat exchange pipes and the heat exchange central pipe through the heat fluid inlet pipe at the upper end. At the heat fluid inlet, the temperature of the heat fluid is the highest and the temperature difference is the largest. Heat is first transferred from the heat fluid to phase change material 1 through the three spiral heat exchange pipes and the heat exchange central pipe. At this time, phase change material with a high melting point absorbs heat to perform first heat exchange. Then, heat is transferred from the heat fluid to phase change material 2 through the three spiral heat exchange pipes and the heat exchange central pipe to perform second heat exchange, thereby completing heat storage. Along the flow direction of the heat fluid, the heat transfer temperature difference continuously decreases, and the melting of the phase change material becomes insufficient. The cylindrical shell can avoid waste of the phase change material. The presence of the three spiral heat exchange pipes and the heat exchange central pipe can increase the heat exchange area, which is conducive to heat transfer and ensures uniform heat. The melting point of phase change material 1 filled in the upper part of the shell is higher than that of phase change material 2 filled in the lower part of the shell, thereby improving the utilization rate of the phase change material. There is a spiral electric heater around the straight pipe in the upper half of the heat exchange central pipe, and there is a tubular electric heater in the middle of the spiral pipe in the lower half of the heat exchange central pipe. Heat can be directly provided by electric heating, which can meet the needs of various working conditions.

[0014] When solidifying and releasing heat, cold fluid enters the three spiral heat exchange pipes and the heat exchange central pipe through the cold fluid inlet pipe at the lower end. Heat is first transferred from phase change material 2 to cold fluid through the three spiral heat exchange pipes and the heat exchange central pipe to perform first heat exchange. Then, heat is transferred from phase change material 1 with a higher temperature melting point to cold fluid through the three spiral heat exchange pipes and the heat exchange central pipe to perform second heat exchange, thereby making the heat exchange more sufficient. Finally, the cold fluid flows out of the heat accumulator through the cold fluid outlet pipe, thereby completing heat release.

Claims

1. A graded cylindrical triple-helix tube phase change accumulator with electric heating, comprising a hot fluid inlet pipe (1), valve 1 (2), valve 2 (3), cold fluid outlet pipe (4), upper end face (5), shell (6), phase change material 1 (7), triple-helix heat exchange tube (8), heat insulation baffle (9), phase change material 2 (10), cold fluid inlet pipe (11), valve 3 (12), hot fluid outlet pipe (13), valve 4 (14), lower end face (15), tubular electric heater (16), heat exchange center tube (17), and spiral electric heater (18); the hot fluid enters the triple-helix heat exchange tube (8) and the heat exchange center tube (17) through the hot fluid inlet pipe (1). Finally, the hot fluid flows out through the hot fluid outlet pipe (13) for heat exchange; the cold fluid enters the triple spiral heat exchange tube (8) and the heat exchange center tube (17) through the cold fluid inlet pipe (11), and finally flows out through the cold fluid outlet pipe (4) for heat exchange; the heat exchange center tube (17) is a straight tube in the upper layer of the shell and a spiral tube in the lower layer of the shell; the shell (6) is filled with phase change heat storage material, and the melting point of the phase change heat storage material filled on the heat insulation baffle (9) in the shell (6) is greater than the melting point of the phase change heat storage material filled below the heat insulation baffle (9) in the shell (6). The hot fluid inlet pipe (1) and the cold fluid outlet pipe (4) are located on the upper end face, and the hot fluid outlet pipe (13) and the cold fluid inlet pipe (11) are located on the lower end face.

2. The electrically heated, staged cylindrical triple-helix tube phase change accumulator according to claim 1, characterized in that, After the fluid flows in through the hot fluid inlet pipe (1), it will flow into the triple spiral heat exchange tube (8) and the heat exchange center tube (17), which are arranged in parallel.

3. The electrically heated, staged cylindrical triple-helix tube phase change accumulator according to claim 1, characterized in that, The heat exchange tube bundle consists of a triple spiral heat exchange tube (8) and a heat exchange center tube (17) with a straight tube in the upper part and a spiral tube in the lower part. The diameter of the triple spiral heat exchange tube (8) is smaller than that of the hot fluid inlet tube (1), and the heat exchange center tube (17) is a straight tube in the upper layer of the shell and a spiral tube in the lower layer of the shell.

4. The electrically heated, staged cylindrical triple-helix tube phase change accumulator according to claim 1, characterized in that, The diameter of the hot fluid inlet pipe (1) is greater than the diameter of the triple spiral heat exchanger (8), the diameter of the triple spiral heat exchanger (8) is equal to the diameter of the heat exchange center pipe (17) in the upper straight pipe of the shell, and the diameter of the heat exchange center pipe (17) in the upper straight pipe of the shell is greater than the diameter of the spiral pipe in the lower spiral pipe of the shell.

5. The electrically heated, staged cylindrical triple-helix tube phase change accumulator according to claim 1, characterized in that, The shell (6) is cylindrical.

6. The electrically heated, staged cylindrical triple-helix tube phase change accumulator according to claim 1, characterized in that, The shell (6) is divided into upper and lower layers by heat insulation baffles (9).

7. The electrically heated, staged cylindrical triple-helix tube phase change accumulator according to claim 1, characterized in that, The heat exchange center tube (17) has a spiral electric heater (18) around the upper straight tube of the shell, and a tubular electric heater (16) in the middle of the lower spiral tube of the shell.

8. The electrically heated, staged cylindrical triple-helix tube phase change accumulator according to claim 1, characterized in that, The outer shell (6) is provided with a heat insulation layer.

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