Vacuum heat insulation-flow heat exchange dual-mode concentrating solar medium and low temperature heat storage system and working method

Abstract

The invention discloses a vacuum heat insulation-flow heat exchange dual-mode concentrating solar medium and low temperature heat storage system and a working method, and belongs to the technical field of heat storage. A medium-low temperature heat storage device in the system is sequentially provided with a phase change heat storage chamber, a water storage tank and a heat preservation shell from inside to outside, and the mode comprises the heat storage mode of the phase change heat storage chamber, the vacuum heat insulation mode of the water storage tank and the water injection heat exchange mode of the water storage tank. When the sun is sufficient in the daytime, solar energy is converted into phase change latent heat of the medium-low temperature heat storage material to be stored, heat is preserved through the vacuum heat insulation layer, heat exchange is conducted through circulating water and the phase change material under the condition that no light exists at night, and therefore an instant and stable heat supply source is provided for heat users. By means of the mode-adjustable medium and low temperature heat storage device, the purposes of high-efficiency heat storage in the daytime and continuous heat supply at night are achieved.

Description

Technical Field

[0001] The present invention relates to the field of heat storage technology, and in particular to a vacuum insulation-fluid heat exchange dual-mode concentrated solar energy medium- and low-temperature heat storage system and a working method. Background Art

[0002] Solar energy is an inexhaustible clean energy source with great application potential in heating. However, there is an intermittent problem in the use of solar thermal energy, which cannot meet the continuous heating needs, especially at night in winter, when users need a lot of heat but there is no sunlight, resulting in intermittent solar heating. Thermal storage technology can make up for the intermittent problem of solar energy during the day and night, and provide a stable heat source at night to meet the heating needs. Summary of the invention

[0003] The purpose of the present invention is to provide a continuous and stable heat source for heat users day and night, and to meet the heating needs of heat users at night. This heat storage device adopts a sleeve structure, the inner cylinder is a phase change heat storage chamber, and the interior is filled with erythritol phase change material; the outer cylinder is a vacuum insulation layer during the heat storage period, which is used for heat preservation and insulation. During the heat release period, circulating water is introduced to exchange heat with the phase change material.

[0004] In order to achieve the above technical features, the purpose of the present invention is achieved as follows: a vacuum insulation-flow heat exchange dual-mode concentrated solar medium and low temperature heat storage system, in which the thermal oil tank of the trough solar collector is connected to the medium and low temperature heat storage device through a pipeline, and the medium and low temperature heat storage device is connected to the heat user after a temperature monitor;

[0005] The medium and low temperature heat storage device is provided with a phase change heat storage chamber, a water storage tank and a heat preservation shell from the inside to the outside in sequence; a serpentine tube and a phase change material are provided in the phase change heat storage chamber, and the phase change material is erythritol, with a thermal conductivity of 0.76 W / (m•K), a phase change latent heat of more than 360 J / g, and a phase change point of 117°C;

[0006] The serpentine tube inlet and the serpentine tube outlet of the serpentine tube are connected to the thermal oil tank on the trough type solar thermal collector;

[0007] A cold water inlet and a hot water outlet are respectively arranged on both sides of the water tank. The cold water inlet of the water tank is connected to a cold water pipe, on which a water pump is arranged. The hot water outlet of the cold water tank is connected to a heat user by a pipeline. The water tank is also provided with a discharge pipe, on which an exhaust port and a drain port are arranged, and a vacuum pump is arranged on the pipeline connected to the exhaust port.

[0008] A working method of a vacuum insulation-fluid heat exchange dual-mode concentrated solar medium and low temperature heat storage system, including the following modes:

[0009] Phase change heat storage chamber heat storage:

[0010] The trough solar collector collects sunlight and heats the thermal oil in the thermal oil tank. The heated thermal oil enters the serpentine tube from the serpentine tube inlet and exchanges heat with the phase change material in the phase change heat storage chamber. The heat is stored in the phase change material. The thermal oil after heat exchange flows back to the thermal oil tank from the serpentine tube outlet through the pipeline to continue heating and sequentially exchange heat.

[0011] Water storage tank vacuum insulation:

[0012] Before the phase change heat storage chamber stores heat, the water in the water storage tank is completely discharged from the drain port through the discharge pipe, and the drain port is closed; the vacuum pump is turned on to evacuate the water storage tank through the exhaust port to below 100 Pa, and the vacuum pump and exhaust port are closed; the water storage tank in a vacuum state serves as the heat insulation layer of the phase change heat storage chamber;

[0013] Water tank filling heat exchange:

[0014] Open the exhaust port to restore the water tank to normal pressure, and turn on the water pump to inject water into the water tank through the cold water pipe and the cold water inlet of the water tank. The water flows from bottom to top through the phase change heat storage chamber and exchanges heat with the phase change material therein to rise in temperature. The obtained hot water is discharged from the hot water outlet of the water tank and delivered to the heat users.

[0015] The system includes a trough solar collector, a medium and low temperature heat storage device, a temperature monitor, a vacuum pump, a water pump, and a heat user; the medium and low temperature heat storage device is a core heat storage component, including a phase change heat storage chamber, a water storage tank, a serpentine pipe, an insulation shell, a bracket, a vacuum pump, and a water pump.

[0016] The serpentine tubes are orthogonally distributed and made of stainless steel to prevent corrosion of erythritol and heat transfer oil. After the high-temperature heat transfer oil in the serpentine tube is fully heat-exchanged in the phase-change heat storage chamber, the low-temperature heat transfer oil flows out from the outlet;

[0017] The volume design of the phase change heat storage chamber and the water storage tank of the medium and low temperature heat storage device needs to be calculated based on local sunshine conditions, temperature conditions and other factors, and the filling ratio of the phase change material can be adjusted according to the season.

[0018] The temperature detector can monitor indoor temperature changes in real time and can also be manually controlled to switch heating modes. The response rate is in seconds and the entire mode switching process is completed within ten minutes.

[0019] Beneficial effects of the present invention: The vacuum insulation-flow heat exchange dual-mode concentrated solar medium and low temperature heat storage system has the advantages of high heat storage density, high heat storage temperature, high heat storage and release efficiency, good day and night continuity, and fast response speed. It can fully convert solar energy and store it into medium and low temperature thermal energy during the day, and provide a large amount of hot water to heat users for heating at night.

[0020] During the day, the trough solar collector converts solar energy into high-temperature heat energy by concentrating light, and transfers it to the phase change heat storage chamber through the heat transfer oil in the serpentine tube, thereby raising the temperature of the phase change material to melting and storing heat energy. The vacuum pump extracts the air in the outer cylinder, reduces the pressure inside the outer cylinder, and improves its thermal insulation capacity. At night, the water pump pumps circulating water into the water storage tank, and the hot water after heat exchange with the phase change material is delivered to the heating users to achieve the purpose of heating. The temperature monitor monitors the indoor temperature changes in real time. When the room temperature is lower than 20℃, the water storage tank immediately releases the vacuum condition and passes cooling water for heat exchange to ensure the indoor temperature in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for describing the embodiments or the prior art are briefly introduced below.

[0022] Figure 1 It is a schematic diagram of a medium and low temperature heat storage device.

[0023] Figure 2 It is a schematic diagram of a vacuum insulation-flow heat exchange dual-mode concentrated solar energy medium and low temperature heat storage system.

[0024] Figure 3 It is a system schematic diagram of a medium and low temperature heat storage device cut away.

[0025] In the figure: 1. Trough solar collector, 2. Medium and low temperature heat storage device, 3. Temperature monitor, 4. Vacuum pump, 5. Water pump, 6. Heat user;

[0026] 201. Phase change heat storage chamber, 202. Water storage tank, 203. Serpentine pipe, 204. Insulation shell, 205. Bracket, 206. Serpentine pipe inlet, 207. Serpentine pipe outlet, 208. Cold water inlet of water storage tank, 209. Hot water outlet of water storage tank, 210. Exhaust port, 211. Drain port, 212. Discharge pipe, 213. Cold water pipe. DETAILED DESCRIPTION

[0027] The specific implementation of the present invention is further explained in conjunction with the accompanying drawings and technical solutions.

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] Example

[0031] Figure 1 and Figure 2 A vacuum insulation-flow heat exchange dual-mode concentrated solar medium and low temperature heat storage system is shown, which is characterized in that: in the system, the heat transfer oil tank of the trough solar collector 1 is connected to the medium and low temperature heat storage device 2 through a pipeline, and the medium and low temperature heat storage device 2 is connected to the heat user 6 through a temperature monitor 3.

[0032] The medium and low temperature heat storage device 2 is provided with a phase change heat storage chamber 201, a water storage tank 202 and a heat insulation shell 204 from the inside to the outside; a serpentine tube 203 and a phase change material are provided in the phase change heat storage chamber 201. The phase change heat storage chamber 201 is a container for storing solid-liquid phase change materials. The phase change material is heated by the heat transfer oil in the internal serpentine tube during the day, and heat is exchanged between the shell of the phase change heat storage chamber and the circulating water at night. The phase change material is erythritol, with a thermal coefficient of 0.76 W / (m•K), a phase change latent heat of more than 360 J / g, and a phase change point of 117°C. It can heat the circulating water to more than 90°C to meet the needs of heat users. The serpentine tube inlet 206 and the serpentine tube outlet 207 of the serpentine tube 203 are connected to the heat transfer oil tank on the trough solar collector 1.

[0033] A water tank cold water inlet 208 and a water tank hot water outlet 209 are respectively arranged on both sides of the water tank 202. The water tank cold water inlet 208 is connected to a cold water pipe 213, and a water pump 5 is arranged on the cold water pipe 213; the cold water tank hot water outlet 209 is connected to a heat user 6 by a pipeline; the water tank 202 is also provided with a discharge pipe 212, and an exhaust port 210 and a drain port 211 are arranged on the discharge pipe 212, and a vacuum pump 4 is arranged on the pipeline connected to the exhaust port 210.

[0034] The water tank 202 has both water storage function and vacuum insulation function. During the heat storage process, the trough solar collector 1 transfers heat to the phase change heat storage chamber 201, the water in the water tank 202 is drained, and the vacuum pump 4 evacuates the gas in the water tank 202. At this time, the water tank acts as an insulation layer to keep the phase change heat storage chamber warm; during the heat release process, the water pump 5 pumps circulating water into the water tank 202 and exchanges heat with the phase change heat storage chamber 201.

[0035] The temperature monitor monitors the indoor temperature changes in real time. When the indoor temperature is higher than 25℃ or is manually regulated, the circulating cooling water system is cut off, the heating process is stopped, and the outer cylinder of the heat storage device is evacuated by a vacuum pump to achieve the purpose of efficient heat storage; when the indoor temperature is lower than 20℃ or is manually regulated, the vacuum condition of the outer cylinder of the heat storage device b is released, the circulating cooling water system is started to resume the heating process, and heat is supplied to the indoor space of the heat user.

[0036] A working method of a vacuum insulation-fluid heat exchange dual-mode concentrated solar medium and low temperature heat storage system, including the following modes:

[0037] Phase change heat storage chamber heat storage:

[0038] The trough solar collector 1 collects sunlight and heats the heat transfer oil in the heat transfer oil tank. The heated heat transfer oil enters the serpentine tube 203 from the serpentine tube inlet 206 and exchanges heat with the phase change material in the phase change heat storage chamber 201. The heat is stored in the phase change material. The heat transfer oil after heat exchange flows back to the heat transfer oil tank from the serpentine tube outlet 207 through the pipeline to continue heating and sequentially exchange heat.

[0039] Water storage tank vacuum insulation:

[0040] Before the phase change heat storage chamber stores heat, the water in the water storage tank 202 is completely discharged from the drain port 211 through the discharge pipe 212, and the drain port 211 is closed; the vacuum pump 4 is turned on to evacuate the water storage tank 202 through the exhaust port 210 to below 100 Pa, and the vacuum pump 4 and the exhaust port 210 are closed; the water storage tank 202 in a vacuum state serves as a heat insulation layer of the phase change heat storage chamber 201;

[0041] Water tank filling heat exchange:

[0042] The exhaust port 210 is opened to restore the water tank 202 to normal pressure, and the water pump 5 is turned on to inject water into the water tank 202 through the cold water pipe 213 and the cold water inlet 208 of the water tank. The water flows from bottom to top through the phase change heat storage chamber 201 and exchanges heat with the phase change material therein to increase the temperature. The obtained hot water is discharged from the hot water outlet 209 of the water tank and delivered to the heat user 6.

[0043] The heat transfer principle of the vacuum insulation-flow heat exchange dual-mode concentrated solar medium and low temperature heat storage system is: under normal circumstances, during the day, sunlight radiates to the trough solar collector for concentration, and the high-temperature heat energy is transferred to the phase change heat storage chamber by the heat transfer oil through the orthogonally distributed serpentine tubes for heat storage. At this time, the water storage tank is emptied of circulating water and evacuated, thereby serving as a vacuum insulation layer to keep the stored heat warm; at night, the water storage tank is filled with circulating water, and the flowing circulating water exchanges heat with the phase change heat storage chamber, and the hot circulating water is transported to the heat user for heating. The entire process is controlled by a temperature detector, based on the instantaneous temperature in the room, and the start and stop response speed of the heating process is fast. The heating mode switch can be completed within a few seconds, and the heating and stopping goals can be achieved within ten minutes.

[0044] The heat exchange process of the heat storage part of the water heater mainly includes two parts: during the daytime heat storage process, the vacuum collector tube converts solar energy into heat energy and transfers it to the circulating water in the water storage tank. After the circulating water heats up, it heats the phase change material cavity. As a result, the circulating water stores sensible heat and the phase change material stores sensible heat and latent heat. At night, the cold circulating water in the serpentine tube exchanges heat with the phase change material, and the generated hot circulating water is supplied to heat users.

[0045] Example 1

[0046] like Figure 1 As shown, the vacuum insulation-flow heat exchange dual-mode concentrated solar medium and low temperature heat storage system is characterized in that the system includes a trough solar collector 1, a medium and low temperature heat storage device 2, a temperature monitor 3, a vacuum pump 4, a water pump 5, and a heat user 6 in sequence. The trough solar collector 1 collects sunlight and heats the heat transfer oil after reaching a higher temperature of about 200°C. The heat transfer oil exchanges heat with the erythritol inside the phase change heat storage chamber 201 through the vertically distributed serpentine tube. In this process, all the water in the water storage tank is discharged through the drain port, and the water storage tank is vacuumed to less than 100 Pa by the vacuum pump 4 as an insulation layer to avoid heat loss in the phase change heat storage chamber. At night, the exhaust hole is opened to restore the water storage tank to normal pressure conditions, and cold circulating water is pumped into the water storage tank through the water pump 5. The circulating water flows from bottom to top through the phase change heat storage chamber and exchanges heat with the phase change material therein to increase the temperature. The obtained hot water is discharged from the hot water outlet at a temperature of more than 90°C and transported to the heat user 6.

[0047] like Figure 2 As shown, the medium and low temperature heat storage device, the heat storage device body includes a phase change heat storage chamber 201, a water storage tank 202, a serpentine tube 203, a heat insulation shell 204, a bracket 205, a vacuum pump 4, and a water pump 5 in sequence. Erythritol is filled in the phase change heat storage chamber as a solid-liquid phase change material, and the phase change point is 117°C. Two sets of vertically distributed serpentine tubes are arranged in the phase change heat storage chamber to enhance heat exchange. The phase change heat storage chamber is made of stainless steel, which can enhance the heat transfer process inside and outside the cavity while avoiding corrosion. Figure 3 It is a system diagram, showing the flow of hot and cold fluids in detail.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vacuum insulation-flow heat exchange dual-mode concentrated solar medium and low temperature heat storage system, characterized by: In the system, a heat transfer oil tank of a trough-type solar thermal collector (1) is connected to a medium-low temperature heat storage device (2) via a pipeline, and the medium-low temperature heat storage device (2) is connected to a heat user (6) via a temperature monitor (3); The medium and low temperature heat storage device (2) is provided with a phase change heat storage chamber (201), a water storage tank (202) and a heat insulation shell (204) in order from the inside to the outside; a serpentine tube (203) and a phase change material are provided in the phase change heat storage chamber (201); the phase change material is erythritol, has a thermal conductivity of 0.76 W / (m•K), a phase change latent heat of more than 360 J / g, and a phase change point of 117°C; The serpentine tube inlet (206) and the serpentine tube outlet (207) of the serpentine tube (203) are in communication with a heat transfer oil tank on the trough type solar thermal collector (1); A water tank cold water inlet (208) and a water tank hot water outlet (209) are respectively arranged on both sides of the water tank (202); the water tank cold water inlet (208) is connected to a cold water pipe (213), and a water pump (5) is arranged on the cold water pipe (213); the cold water tank hot water outlet (209) is connected to a heat user (6) by a pipeline; the water tank (202) is also provided with a discharge pipe (212), and an exhaust port (210) and a drain port (211) are arranged on the discharge pipe (212); a vacuum pump (4) is arranged on the pipeline connected to the exhaust port (210).

2. The working method of the vacuum insulation-fluid heat exchange dual-mode concentrated solar medium and low temperature heat storage system according to claim 1 is characterized in that: The following modes are included: Phase change heat storage chamber heat storage: The trough-type solar thermal collector (1) collects sunlight to heat the heat transfer oil in the heat transfer oil tank. The heated heat transfer oil enters the serpentine tube (203) from the serpentine tube inlet (206) to exchange heat with the phase change material in the phase change heat storage chamber (201), and the heat is stored in the phase change material. The heat transfer oil after the heat exchange flows back to the heat transfer oil tank from the serpentine tube outlet (207) through the pipeline, and continues to be heated, and the heat is exchanged sequentially. Water storage tank vacuum insulation: Before the phase change heat storage chamber stores heat, all water in the water storage tank (202) is discharged from the drain port (211) through the discharge pipe (212), and the drain port (211) is closed; the vacuum pump (4) is turned on to evacuate the water storage tank (202) through the exhaust port (210) to a pressure below 100 Pa, and the vacuum pump (4) and the exhaust port (210) are turned off; the water storage tank (202) in a vacuum state serves as a heat insulation layer for the phase change heat storage chamber (201); Water tank filling heat exchange: The exhaust port (210) is opened to restore the water tank (202) to normal pressure, and the water pump (5) is turned on to inject water into the water tank (202) through the cold water pipe (213) and the cold water inlet (208) of the water tank. The water flows from bottom to top through the phase change heat storage chamber (201) and exchanges heat with the phase change material therein to increase the temperature. The obtained hot water is discharged from the hot water outlet (209) of the water tank and transported to the heat user (6).

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