Three-phase absorption heat storage system

Abstract

The present invention relates to a three-phase absorption heat storage system, comprising a solution reactor and a refrigerant reactor. The solution reactor comprises a solution tank, a solution spray disc, a solution falling film heat exchanger, a solution filter cartridge, a solution pump, and a solution circulating pipeline. The bottom end of the solution filter cartridge is communicated with an inlet of the solution pump, and an outlet of the solution pump is communicated with the solution spray disc by means of the solution circulating pipeline to form solution circulation. A filter screen for a solution to pass through is arranged at the upper part in the solution filter cartridge, to achieve high-level liquid inlet. The refrigerant reactor comprises a refrigerant tank, a refrigerant water spray disc, a refrigerant falling film heat exchanger, a refrigerant pump, and a refrigerant circulating pipeline. The bottom end of the refrigerant tank is communicated with an inlet of the refrigerant pump, and an outlet of the refrigerant pump is communicated with the refrigerant water spray disc by means of the refrigerant circulating pipeline to form refrigerant circulation. The top of the solution tank is communicated with the top of the refrigerant tank by means of a steam pipeline. Working stages of the three-phase absorption heat storage system include a heat charging stage and a heat release stage, and the heat release stage can realize a heating function, a hot water production function, or a refrigeration function. According to the present invention, after the solution is crystallized, stable operation can still be achieved, and three-phase heat storage is achieved.

Description

Three-phase absorption heat storage system Technical Field

[0001] The present invention relates to the technical field of heat storage systems, and in particular to an absorption heat storage system driven by solar energy. Background Art

[0002] With the development of society and population growth, energy consumption has also increased dramatically. Energy shortages caused by over-reliance on fossil fuels have become a major challenge facing human society, and the environmental problems associated with energy consumption are also becoming increasingly serious. Energy and environmental issues have become urgent challenges that need to be addressed. Vigorously developing renewable energy and improving energy efficiency are two practical solutions that are of great significance to ensuring the sustainable development of human society.

[0003] As a renewable energy source, solar energy is increasingly being used in heating and cooling. The most common is the solar heating system, which uses solar collectors to collect solar radiation and convert it into thermal energy. Using water as a heat transfer medium, the heat is delivered indoors to meet heating and hot water needs, playing an important role in replacing coal-fired heating. However, solar energy is unstable and intermittent over time, which causes a temporal mismatch between the heating supply and demand sides. For example, in the summer when there is ample sunlight, the demand for heating is low, while in the winter when the demand for heating increases but the intensity of solar radiation is greatly reduced. This mismatch has become a bottleneck problem in the use of solar thermal energy. How to efficiently store solar thermal energy has become the key to solving this problem, especially the mismatch between the supply and demand of solar thermal energy in different seasons, which requires efficient long-cycle heat storage technology to solve.

[0004] According to the principle of heat storage, it can be divided into three categories: sensible heat, latent heat and thermochemistry. Absorption heat storage is one of the thermochemical heat storage methods. It mainly draws on the working principle of the gas-liquid absorption cycle. In the charging stage, thermal energy is converted into the chemical energy of the working fluid, and in the heat release stage, the chemical energy is converted into heat / cold energy. The total heat loss during the storage process is only the sensible heat loss of the working fluid from the working temperature to the ambient temperature. The heat loss is small and it is more suitable for long-term heat storage. To store the same amount of heat, the volume required for absorption heat storage is 1 / 3 of that for sensible heat storage (water) and 1 / 2 of that for phase change latent heat. Due to its high energy storage density, long heat storage cycle, and the integration of heat storage and cold storage, absorption heat storage is considered to be an efficient, stable and flexible heat storage technology with good application scenarios in the field of housing construction engineering.

[0005] The energy storage density of an absorption thermal storage system is directly related to the maximum concentration difference achieved by the solution throughout the entire cycle. However, when the solution concentration exceeds the solubility limit or the solution temperature drops below the crystallization temperature, crystallization will occur in the solution. In traditional absorption systems, solution crystallization can block the solution circulation loop, causing the circulation pump and shower tray to malfunction, posing a significant threat to the reliability and safety of the unit. Therefore, traditional absorption thermal storage systems avoid crystallization by limiting the solution concentration, but this also results in limited system energy storage density.

[0006] Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the shortcomings of the conventional absorption heat storage system in the above-mentioned prior art, that is, the circulation concentration difference and energy storage density are limited by the crystallization of the solution. A three-phase absorption heat storage system is provided, which efficiently converts the external input heat energy into the chemical energy of the solution working fluid. At the same time, the unit can operate normally after the solution crystallizes, thereby increasing the concentration range in which the unit can operate and improving the energy storage density of the absorption heat storage system. Compared with the traditional absorption heat storage system, its heat storage capacity and energy storage density are significantly improved.

[0008] The technical solution adopted by the present invention to solve the above-mentioned technical problems is:

[0009] A three-phase absorption heat storage system includes a solution reactor and a refrigerant reactor; the solution reactor includes a solution tank, a solution shower tray, a solution falling film heat exchanger, a solution filter cartridge, a solution pump and a solution circulation pipeline, the solution shower tray, the solution falling film heat exchanger and the solution filter cartridge are arranged in sequence from top to bottom in the solution tank, the solution pump and the solution circulation pipeline are arranged outside the solution tank, the bottom end of the solution filter cartridge is connected to the solution pump inlet, and the solution pump outlet is connected to the solution shower tray through the solution circulation pipeline to form a solution circulation; a filter screen is provided in the upper middle part of the solution filter cartridge for solution to pass through, so as to realize high-level liquid inlet; the refrigerant reactor The device includes a refrigerant tank, a refrigerant water spray pan, a refrigerant falling film heat exchanger, a refrigerant pump and a refrigerant circulation pipeline. The refrigerant water spray pan and the refrigerant falling film heat exchanger are arranged in the refrigerant tank from top to bottom in sequence. The refrigerant pump and the refrigerant circulation pipeline are arranged outside the refrigerant tank. The bottom end of the refrigerant tank is connected with the refrigerant pump inlet, and the refrigerant pump outlet is connected with the refrigerant water spray pan through the refrigerant circulation pipeline to form a refrigerant circulation; the solution tank is connected with the top of the refrigerant tank through a steam pipeline; the working stages of the three-phase absorption heat storage system include a heat charging stage and a heat release stage. The heat release stage can realize heating function, hot water making function or cooling function.

[0010] In the above scheme, a solution valve is provided on the connecting pipe between the solution filter cartridge and the solution pump; a generator inlet valve is provided at the solution shower tray inlet on the solution circulation pipe; a refrigerant water shower tray valve is provided on the connecting pipe between the refrigerant tank and the refrigerant pump; and an energy storage shut-off valve is provided on the steam pipe between the solution tank and the refrigerant tank.

[0011] In the above scheme, during the heat charging stage, hot water and cooling water are respectively introduced into the solution falling film heat exchanger and the refrigerant falling film heat exchanger tubes, the solution circulation is running, and the refrigerant water circulation is not running. In the solution circulation, the solution passes through the solution filter cartridge, the solution pump, the solution shower tray and the solution falling film heat exchanger in sequence, absorbs the heat of the hot water in the solution falling film heat exchanger tube, and the generated refrigerant vapor enters the refrigerant tank through the steam pipe and condenses into liquid refrigerant. The released condensation heat is taken away by the cooling water.

[0012] In the above scheme, under the heating function or hot water function during the heat release stage, heated water and low-temperature water are respectively introduced into the solution falling film heat exchanger and the refrigerant falling film heat exchanger tubes, and the solution circulation and refrigerant circulation operate simultaneously. The liquid refrigerant passes through the refrigerant pump, the refrigerant water spray pan and the refrigerant falling film heat exchanger in sequence, absorbs the heat of the low-temperature water in the refrigerant falling film heat exchanger tube and evaporates. The gaseous refrigerant enters the solution tank through the steam pipe and is finally absorbed by the solution. The released heat is carried out by the heated water.

[0013] In the above scheme, under the refrigeration function during the heat release stage, cooling water and low-temperature water are respectively introduced into the solution falling film heat exchanger and the refrigerant falling film heat exchanger tubes, and the solution circulation and refrigerant circulation are operated simultaneously. The liquid refrigerant passes through the refrigerant pump, the refrigerant water shower tray and the refrigerant falling film heat exchanger in sequence, absorbs the heat of the low-temperature water in the refrigerant falling film heat exchanger tube and evaporates, thereby reducing the low-temperature water temperature to achieve refrigeration output, and the solution tank is cooled by the cooling water in the solution falling film heat exchanger tube.

[0014] In the above scheme, the three-phase absorption heat storage system also includes a refrigerant bypass pipe and a flushing bypass pipe; the refrigerant bypass pipe connects the refrigerant circulation pipe and the solution pump, and the lower end of the flushing bypass pipe is connected to the solution pump inlet and the upper end is connected to the upper end of the solution circulation pipe; after the charging / discharging stage, a small amount of refrigerant water is drawn from the refrigerant tank into the solution pump and the solution circulation pipe. The refrigerant water circulates between the solution pump, the solution circulation pipe and the flushing bypass pipe, and dilutes the residual concentrated solution therein. The diluted solution is finally pumped to the solution shower tray and the solution falling film heat exchanger for flushing, and enters the solution tank, thereby avoiding crystallization of the solution in the solution pump and the solution circulation pipe after cooling.

[0015] In the above scheme, a refrigerant bypass valve is provided on the refrigerant bypass pipe; a lower valve is provided at the lower end of the flushing bypass pipe, and an upper valve is provided at the upper end of the flushing bypass pipe; when the system is in normal operation during the heat charging or heat release stage, in order to prevent the solution from entering the flushing bypass pipe and causing crystallization blockage, the upper valve and the lower valve need to be closed; when the system is flushed, in order to circulate and dilute the flushing refrigerant water with the residual concentrated solution, the upper valve and the lower valve need to be opened; when the system is flushed, in order to drain the residual solution in the flushing bypass pipe, the upper valve needs to be closed and the lower valve opened.

[0016] In the above solution, the solution reactor further comprises a heating device, which is arranged inside the solution filter cartridge and is used to melt crystals at the outlet of the solution tank before the exothermic stage of the system operation or in the late stage of the heat charging stage.

[0017] In the above solution, the heating device is an electric heating rod, a blind tube is installed in the solution filter cartridge, and the electric heating rod is inserted into the blind tube.

[0018] In the above scheme, two solution filter cartridges are vertically arranged in the solution tank, one of which is provided with a short filter screen to achieve high-position liquid inlet, and the other is provided with a long filter screen, the bottom of the long filter screen is lower than the bottom of the short filter screen, and is used to achieve liquid inlet after the solution is reduced.

[0019] The beneficial effects of the present invention are:

[0020] The present invention uses the filtering effect of the solution filter cartridge and the melting crystal effect of the heating device to concentrate the solution to a crystalline state, and can still operate stably after the solution crystallizes, realizing three-phase heat storage, desorbing more refrigerant and utilizing the heat of solution crystallization, providing a solution to the crystallization limitation of the absorption heat storage system and thus improving the system's energy storage density. It can convert solar energy or low-grade energy into thermal energy and store it efficiently, and provide multiple outputs such as heating, domestic hot water and cooling, providing a preferred solution for the efficient utilization of these energy sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0022] FIG1 is a schematic structural diagram of a three-phase absorption heat storage system according to the present invention;

[0023] FIG2 is a schematic diagram of the three-phase absorption heat storage system of the present invention in operation during the heat charging stage;

[0024] FIG3 is a schematic diagram of the three-phase absorption heat storage system of the present invention operating in the heat release stage;

[0025] FIG4 is a side view of FIG1;

[0026] FIG5 is a control logic diagram of the heat charging process of the three-phase absorption heat storage system in an embodiment of the present invention.

[0027] FIG6 is a control logic diagram of the flushing sub-process of the three-phase absorption heat storage system in an embodiment of the present invention.

[0028] FIG7 is a control logic diagram of the heat release process of the three-phase absorption heat storage system in an embodiment of the present invention.

[0029] FIG8 is a control logic diagram of the refrigeration process of the three-phase absorption thermal storage system according to an embodiment of the present invention.

[0030] In the figure: 10, solution reactor; 11, solution tank; 12, solution shower tray; 13, solution falling-film heat exchanger; 14, solution filter cartridge; 15, heating device; 16, solution pump; 17, solution circulation pipeline; F1, generator inlet valve; F5, first solution valve; F6, second solution valve; 20, refrigerant reactor; 21, refrigerant tank; 22, refrigerant water shower tray; 23, refrigerant falling-film heat exchanger; 24, refrigerant pump; 25, refrigerant circulation pipeline; F7, refrigerant water shower tray valve; 30, steam pipeline; F3, energy storage shut-off valve; 40, refrigerant bypass pipeline; F8, refrigerant bypass valve; 50, flushing bypass pipeline; F2, upper valve; F4, lower valve; 60, sight glass;

[0031] The solid line represents liquid flow, the dotted line represents gas flow, the arrows represent flow direction, and the arrows at the falling film heat exchanger represent heat flow inside the reactor. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0033] As shown in Figure 1, an embodiment of the present invention provides a three-phase absorption heat storage system. This system can operate stably in a solid-liquid mixed state with crystals in the solution, achieving a three-phase absorption process, thereby significantly improving the system's energy storage density. The three-phase absorption heat storage system includes a solution reactor 10 and a refrigerant reactor 20. The solution reactor 10 is used for absorbing, desorbing, and storing the solution working fluid, and the refrigerant reactor 20 is used for evaporating, condensing, and storing the refrigerant.

[0034] The solution reactor 10 includes a solution tank 11, a solution shower tray 12, a solution falling film heat exchanger 13, a solution filter cartridge 14, a solution pump 16, and a solution circulation pipeline 17. The solution shower tray 12, the solution falling film heat exchanger 13, and the solution filter cartridge 14 are sequentially arranged inside the solution tank 11 from top to bottom. The solution pump 16 and the solution circulation pipeline 17 are located outside the solution tank 11. The bottom end of the solution filter cartridge 14 is connected to the inlet of the solution pump 16, and the outlet of the solution pump 16 is connected to the solution shower tray 12 via the solution circulation pipeline 17, forming a solution circulation system. A solution valve is installed on the connecting pipeline between the solution filter cartridge 14 and the solution pump 16; and a generator inlet valve F1 is installed on the solution circulation pipeline 17 at the inlet of the solution shower tray 12. In the solution reactor 10, the solution flows as follows: after passing through the solution filter cartridge 14, the solution enters the circulation pipeline from the bottom of the solution tank 11, passes through the solution valve, solution pump 16 and generator valve F1 in sequence, and then enters the solution shower tray 12 at the top of the solution tank 11 and is sprayed to the solution falling film heat exchanger 13.

[0035] The solution filter cartridge 14 is vertically installed in the solution tank 11. A filter screen is provided in the upper portion of the solution filter cartridge 14 for the solution to pass through, thereby achieving high-position liquid inlet, i.e., raising the position of the liquid inlet so that only the solution at the upper position can enter the solution circulation loop. Since the concentrated solution and crystals are mainly concentrated at the bottom of the solution tank 11, the use of high-position liquid inlet can effectively reduce the risk of crystallization blockage. Before entering the circulation loop, the solution needs to pass through the solution filter cartridge 14. The crystals carried by the solution are filtered out by the filter screen on the side wall of the filter cartridge to avoid solution circulation blockage, so that the system can continue to operate after the solution crystallizes, realizing three-phase heat storage, desorbing more refrigerant, and utilizing the heat of the crystallization reaction of the solution crystallization.

[0036] The refrigerant reactor 20 includes a refrigerant tank 21, a refrigerant water shower 22, a refrigerant falling film heat exchanger 23, a refrigerant pump 24, and a refrigerant circulation pipeline 25. The refrigerant water shower 22 and refrigerant falling film heat exchanger 23 are sequentially arranged inside the refrigerant tank 21, while the refrigerant pump 24 and refrigerant circulation pipeline 25 are located outside the refrigerant tank 21. The bottom of the refrigerant tank 21 is connected to the inlet of the refrigerant pump 24, and the outlet of the refrigerant pump 24 is connected to the refrigerant water shower 22 via the refrigerant circulation pipeline 25, forming a refrigerant circulation system. A refrigerant water shower valve F7 is installed on the connecting pipeline between the refrigerant tank 21 and the refrigerant pump 24. In the refrigerant reactor 20, the flow pattern of the refrigerant water is as follows: after the refrigerant water flows out of the refrigerant tank 21 from the bottom, it passes through the refrigerant water shower valve F7 and the refrigerant pump 24 in sequence, is pumped to the refrigerant water shower tray 22 at the top of the refrigerant tank 21, and is sprayed to the refrigerant falling film heat exchanger 23.

[0037] The top of the solution tank 11 is connected to the top of the refrigerant tank 21 through a steam pipe 30 , and an energy storage stop valve F3 is provided on the steam pipe 30 .

[0038] The working stages of the three-phase absorption heat storage system include the charging stage and the heat release stage. The heat release stage can realize the heating function, hot water making function or cooling function.

[0039] During the charging phase, the heat input to the solution reactor 10 comes from a high-temperature heat source (such as solar water heating), and the heat released by the refrigerant reactor 20 is absorbed by the environment. As shown in Figure 2, hot water and cooling water are respectively introduced into the pipes of the solution falling film heat exchanger 13 and the refrigerant falling film heat exchanger 23. The solution cycle is in operation, while the refrigerant water cycle is not in operation. During the solution cycle, the solution passes through the solution filter cartridge 14, the solution pump 16, the solution shower tray 12, and the solution falling film heat exchanger 13 in sequence, absorbing the heat of the hot water in the pipes of the solution falling film heat exchanger 13. At the same time, the solution desorbs refrigerant vapor. The generated refrigerant vapor enters the refrigerant tank 21 through the steam pipe 30 and condenses into liquid refrigerant. The released condensation heat is carried away by the cooling water.

[0040] During the heat release phase, when operating in the heating or hot water production function, the solution reactor 10 serves as the heat output component, while the refrigerant reactor 20 absorbs heat input from the environment or a low-temperature heat source. As shown in Figure 3, heated water and low-temperature water are introduced into the solution falling-film heat exchanger 13 and refrigerant falling-film heat exchanger 23, respectively. The solution and refrigerant circulations operate simultaneously. The liquid refrigerant passes through the refrigerant pump 24, the refrigerant water shower 22, and the refrigerant falling-film heat exchanger 23, absorbing heat from the low-temperature water in the refrigerant falling-film heat exchanger 23 and evaporating. The gaseous refrigerant enters the solution tank 11 through the steam line 30, where it is ultimately absorbed by the solution. The released heat is then carried away by the heated water. The system output temperature can be adjusted between 40°C and 65°C to achieve heating or domestic hot water output.

[0041] During the heat release phase, the heat released by the solution reactor 10 is absorbed by the environment, and the refrigerant reactor 20 outputs cooling capacity. Continuing with Figure 3, cooling water and low-temperature water are introduced into the tubes of the solution falling-film heat exchanger 13 and the refrigerant falling-film heat exchanger 23, respectively. The solution and refrigerant circulations operate simultaneously, with the liquid refrigerant passing through the refrigerant pump 24, the refrigerant water shower pan 22, and the refrigerant falling-film heat exchanger 23, absorbing heat from the low-temperature water in the tubes of the refrigerant falling-film heat exchanger 23 and evaporating, thereby lowering the temperature of the low-temperature water and achieving cooling output. The system can achieve a cooling temperature of 7°C. The solution tank 11 is cooled by the cooling water in the tubes of the solution falling-film heat exchanger 13.

[0042] Further optimizations have been made to the three-phase absorption thermal storage system, which also includes a refrigerant bypass pipe 40 and a flushing bypass pipe 50. Refrigerant bypass pipe 40 connects the refrigerant circulation pipe 25 with the solution pump 16 and is equipped with a refrigerant bypass valve F8. The flushing bypass pipe 50 has its lower end connected to the inlet of the solution pump 16 and its upper end connected to the upper end of the solution circulation pipe 17. A lower valve F4 is installed at the lower end of the flushing bypass pipe 50, and an upper valve F2 is installed at the upper end of the flushing bypass pipe 50. If a portion of concentrated solution remains in the solution pump 16 and the solution circulation pipe 17 after charging / discharging / cooling, the addition of the refrigerant bypass pipe 40 between the solution pump 16 and the refrigerant circulation pipe 25 allows a small amount of refrigerant water to be drawn from the refrigerant tank 21 to flush the solution pump 16 and the solution circulation pipe 17, preventing the remaining solution from crystallizing after cooling. In order to achieve sufficient flushing, a bypass pipe is added to the solution circulation pipe 17. The refrigerant water circulates between the solution pipe and the bypass pipe to flush and dilute for a period of time. The diluted solution is finally pumped to the solution shower tray 12.

[0043] To further optimize the system and ensure stable operation, the three-phase absorption heat storage system also includes a heating device 15 installed in the solution filter cartridge 14. This device is used to melt crystals at the outlet of the solution tank 11 before the system's heat release phase or in the later stages of the heat charging phase. Specifically, the heating device 15 uses an electric heating rod, and a blind pipe is installed in the solution filter cartridge 14. After the prototype is assembled, the electric heating rod is inserted into the blind pipe and thermal oil is poured in. When the system is operating, the high-level liquid inlet and filter screen ensure that the solution circulation loop is not blocked. However, in the non-operating state, as the solution temperature continues to decrease, more and more solution reaches below the crystallization temperature and crystallizes. These crystals accumulate at the bottom of the solution tank 11 and block the solution outlet. Therefore, before the next operation, an electric heating rod is required to melt crystals to allow the solution to enter the solution pump 16 smoothly. In the later stages of the heat charging phase, the solution gradually crystallizes. If necessary, the electric heating can be turned on to wait until the solution is evenly mixed and the circulation is normal before continuing to crystallize. This can increase the upper concentration limit and improve the heat storage density.

[0044] As a further optimization, the three-phase absorption heat storage system also includes various detection devices for measuring the solution, refrigerant, and inlet and outlet water temperatures of the two falling-film heat exchangers. The solution temperature includes the solution generation temperature, the solution bottom temperature, and the temperature in the solution circulation loop. The refrigerant temperature is the condensation / evaporation temperature in the refrigerant tank 21. The flow rate in the solution circulation is also measured to determine the system's crystallization status and whether there is any blockage.

[0045] As further optimized, as shown in Figure 4, two solution filter cartridges 14 are vertically arranged within the solution tank 11. One solution filter cartridge 14 is equipped with a short filter screen to achieve high-level liquid inlet, and the other solution filter cartridge 14 is equipped with a long filter screen, with the bottom of the long filter screen lower than the bottom of the short filter screen, to serve as a backup after the solution is reduced. Both solution filter cartridges 14 are internally installed with a heating device 15. A first solution valve F5 is installed on the connecting pipe between the short filter screen solution filter cartridge 14 and the solution pump 16, and a second solution valve F6 is installed on the connecting pipe between the long filter screen solution filter cartridge 14 and the solution pump 16.

[0046] For further optimization, solution tank 11 uses lithium bromide solution, lithium chloride solution, or calcium chloride solution as the circulating working fluid; refrigerant tank 21 uses water as the refrigerant. The mass fraction of the refrigerant varies with the generation and absorption of the circulating working fluid. For example, the circulating medium solution is lithium bromide solution, the working fluid is lithium bromide, and the refrigerant is water. Furthermore, the working fluid in the falling film heat exchanger tubes is water.

[0047] For further optimization, the three-phase absorption heat storage system also includes a vacuum pump, which is used for regular vacuum maintenance of the unit.

[0048] For further optimization, the three-phase absorption heat storage system also includes sight glasses 60 installed in the solution tank 11 and the refrigerant tank 21 respectively, which are used to observe the operation of the system, including the solution level, the refrigerant level and the solution crystallization, etc., to facilitate fault analysis and debugging and maintenance.

[0049] The heat storage density of an absorption heat storage system is proportional to the concentration difference of the circulating solution. In conventional absorption heat storage systems, crystallization prevents the solution from circulating, leading to circulation failure. To prevent crystallization during charging or storage, the concentration difference that can be achieved is limited. The high energy storage density of the three-phase absorption heat storage system of the present invention is primarily due to the increased heat storage capacity and concentration difference range during the solution crystallization process. Through the filtration of the solution cartridge and the melting crystallization action of the heating device, the three-phase absorption heat storage system concentrates the solution to a crystalline state and maintains stable operation even after crystallization, achieving three-phase heat storage. On the one hand, the system can operate at higher solution solubility, resulting in a greater concentration difference before and after charging. This allows for the desorption of more refrigerant from a unit of working fluid. This increased latent heat of the refrigerant can be utilized during the heat release or cooling process, resulting in greater heat release or cooling capacity, thereby increasing the energy storage density per unit of working fluid. On the other hand, the crystals in the solution release more heat during dissolution, which can be used for external heat output from the system, thereby increasing the energy storage density per unit of working fluid.

[0050] The following describes in detail the various operating modes of the three-phase absorption heat storage system of the present invention, taking heating / hot water production / cooling in high altitude areas as an example.

[0051] As shown in FIG5 , in the heating stage, to ensure that the solution reaches a crystallized state during the heating stage, the heat source temperature of the solution is above 85° C., while the cold source temperature of the refrigerant tank 21 is below 20° C.

[0052] "Heating start": hot water (the inlet temperature is the heat source temperature, such as 85 ~ 90 degrees, 5m 3 / h) and cooling water (the inlet temperature is the ambient temperature, such as 15 degrees, 5m 3 / h), turn on F1, adjust the frequency of solution pump 16 to approximately 11, turn on solution pump 16, turn on F5 and F6, and slightly open F3 (to approximately 4), and continue for approximately 45 minutes. It should be noted that at the beginning of hot charging, due to the low solution temperature, the frequency of solution pump 16 and F3 should not be turned too high to prevent the solution from boiling too quickly, causing solution splashing into the refrigerant tank 21 and causing contamination.

[0053] "Charging in progress": The frequency of the solution pump 16 is adjusted to about 18, and F3 is fully opened. It should be noted that in the middle of charging, the solution is basically stable and will not boil violently. The boiling should be accelerated to shorten the charging time.

[0054] "Late heating": If no solution circulation flow is detected (indicating crystallization blockage), turn off F3 and wait for 15 minutes; if solution circulation flow is detected, slightly open F3 (opening to about 3). If solution circulation flow is still not detected after waiting for 15 minutes, turn on the electric heating until solution circulation flow is detected, turn off the electric heating, and slightly open F3 (opening to about 3). It should be noted that in the late heating, the solution gradually crystallizes. If a significant drop in the flow rate during solution circulation is detected, it means that there are many crystals in the solution tank 11 and the solution pump 16 has a small amount of liquid. At this time, the heating amount is close to the maximum value. When crystallization blockage occurs, it should be avoided that it occurs too quickly, resulting in rapid crystallization and aggravated blockage. Therefore, F3 needs to be turned down to reduce the solution generation rate. If necessary, the electric heating can be turned on to wait until the solution is evenly mixed and the circulation is normal before continuing to generate, thereby extending the heating time.

[0055] "Hot Charging Ended": If the liquid level in the refrigerant tank 21 returns to the specified level, the solution pump 16 and corresponding pipes and valves must be flushed immediately to prevent the concentrated solution from crystallizing after cooling. After the flushing is completed, all valves, pumps, hot water, and cooling water are closed, and hot charging is completed. It should be noted that at the end of hot charging, the liquid level should return to the level before heat release to prepare for the next heat release.

[0056] The above flushing process is shown in Figure 6:

[0057] "Flush": Turn off F5 and F6, wait until no solution circulation flow is detected and then wait for 2 minutes (drain the solution pipeline); turn off F1, turn on F2, turn on F4, wait for 5 minutes (the solution circulates between the solution circulation pipeline 17 and the flushing bypass pipeline 50); turn on F1, turn off F2, wait until no solution circulation flow is detected and then wait for 2 minutes (drain the solution circulation pipeline 17 and the flushing bypass pipeline 50); turn off F4, adjust the frequency of the solution pump 16 to about 16, and the frequency of the refrigerant pump 24 to about 18, Turn on F8, wait for 15 seconds, turn off F8 (refrigerant water bypass flushing solution pump 16 and solution circulation pipe 17); turn off F1, turn on F2, turn on F4, wait for 5 minutes (repeat solution circulation between solution circulation pipe 17 and flushing bypass pipe 50); turn on F1, turn off F2, wait until no solution circulation flow is detected, and then wait for 2 minutes (empty solution circulation pipe 17 and flushing bypass pipe 50); if the temperature in the solution circulation loop is detected to be lower than 40 degrees, the flushing is completed; otherwise, repeat the flushing.

[0058] “Flushing Ended”: All valves, pumps, hot water and cooling water are turned off.

[0059] During the heat release stage, under the heating function or hot water making function, the heated water in the solution falling film heat exchanger 13 tube is heated by the solution tank 11, and the outlet water temperature can reach 45-65°C, realizing heating or domestic hot water output; during the heat release stage, under the cooling function, the cooling output is realized by absorbing heat through the evaporation of the refrigerant, and the outlet water temperature can reach 7°C.

[0060] The specific control logic of the heating function or hot water function in the heat release stage is shown in Figure 7:

[0061] "Exothermic start": pass water for evaporation (the inlet temperature during heating is the ambient temperature, such as 15 degrees, 5m 3 / h, the inlet temperature is 12 degrees when cooling, 2m 3 / h), turn on F7, turn on the refrigerant pump 24, and adjust the frequency of the refrigerant pump 24 to about 18; turn on the electric heating, turn on F1, adjust the frequency of the solution pump 16 to about 16, turn on the solution pump 16, turn on F5 and F6, and slightly open F3 (about 4 degrees); wait until the solution circulation flow is detected, turn off the electric heating, and pass the heated water (the inlet temperature is 42 degrees when heating, 2m 3 / h, the inlet temperature during cooling is the ambient temperature, such as 30 degrees, 5m 3 / h). It should be noted that, in order to clear the solution channel at the beginning of heat release, it is necessary to turn on the electric heating to melt the crystal first, and then turn on the heated water after the solution circulates, so as to prevent the heated water from cooling the solution and causing crystallization.

[0062] "Initial Heat Release": Detects the outlet temperature of the heated water (standard: 45°C for heating, 65°C for hot water). If the outlet temperature is above the standard, shut off the solution pump 16; if it is below the standard, shut off the solution pump 16. It should be noted that in the initial stage of heat release, due to the high concentration of the solution and the intense heat absorption and release, the outlet temperature of the heated water will quickly rise above the standard. Therefore, it is necessary to start and stop the solution circulation to maintain a stable outlet temperature.

[0063] "Mid-stage heat release": If the heated water outlet temperature remains below the standard after the solution pump has been running for 5 minutes, adjust the frequency of solution pump 16 to approximately 27, the frequency of refrigerant pump 24 to approximately 30, and fully open F3. If the heated water outlet temperature is higher than the standard, shut off solution pump 16. If the heated water outlet temperature is lower than the standard, reopen solution pump 16. It should be noted that during the mid-stage heat release, due to the gradual dilution of the solution and the weakening of absorption, the heated water outlet temperature may fall below the standard. At this time, the solution circulation rate should be increased and F3 should be fully opened to enhance solution absorption and heat release.

[0064] "Late Exotherm": If the heated water outlet temperature remains below the standard after the solution pump has been running for 5 minutes, gradually increase the evaporation water inlet temperature by 0.5 degrees. It should be noted that in the late exotherm, even though the solution circulation and F3 settings have been maximized, the solution is too dilute to meet the temperature rise requirements, so the evaporation temperature must be gradually increased.

[0065] "Exothermic End": If the refrigerant tank 21 level is detected to have dropped to the specified level, all valves, pumps, heated water, and evaporative water are closed. It should be noted that after exothermic end, not all refrigerant must be discharged; a portion must be reserved for the next flushing step. The flushing process and control logic are the same as the flushing at the end of hot charging. Although the solution is at its most dilute state after exothermic end, there is still a risk of crystallization in low-temperature environments, so flushing is necessary.

[0066] The cooling function in the heat release phase is similar to the heating function or hot water function in the heat release phase. The specific control logic is shown in Figure 8:

[0067] "Start Refrigeration": Turn on cold water, turn on F7, turn on refrigerant pump 24, and adjust the frequency of refrigerant pump 24 to about 18; turn on electric heating, turn on F1, adjust the frequency of solution pump 16 to about 16, turn on solution pump 16, turn on F5 and F6, and slightly open F3 (to about 4); wait until solution circulation flow is detected, turn off electric heating, and turn on cooling water.

[0068] "Initial stage of refrigeration": detect the outlet temperature of cold water (standard: 7 degrees); if the outlet temperature of cold water is lower than the standard, turn off the solution pump 16; if the outlet temperature of cold water is lower than the standard, turn on the solution pump 16.

[0069] "Mid-cooling": If the cold water outlet temperature is still higher than the standard after the solution pump is turned on for 5 minutes, adjust the frequency of solution pump 16 to about 27, the frequency of refrigerant pump 24 to about 30, and fully open F3; if the cold water outlet temperature is lower than the standard, turn off solution pump 16; if the cold water outlet temperature is higher than the standard, turn on solution pump 16.

[0070] "Late cooling stage": If the cold water outlet temperature is still higher than the standard after the solution pump is turned on for 5 minutes, gradually reduce the cooling water inlet temperature by 0.5 degrees each time.

[0071] "Refrigeration End": If the liquid level in the refrigerant tank 21 drops to the specified level, the valves, pumps, cold water, and cooling water are all closed. It should be noted that after the refrigeration is completed, the refrigerant cannot be completely discharged, and a portion needs to be reserved for the next flushing step.

[0072] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0073] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A three-phase absorption heat storage system, characterized in that: including a solution reactor and a refrigerant reactor; The solution reactor comprises a solution tank, a solution shower tray, a solution falling film heat exchanger, a solution filter cartridge, a solution pump and a solution circulation pipeline. The solution shower tray, the solution falling film heat exchanger and the solution filter cartridge are sequentially arranged in the solution tank from top to bottom. The solution pump and the solution circulation pipeline are arranged outside the solution tank. The bottom end of the solution filter cartridge is connected to the inlet of the solution pump, and the outlet of the solution pump is connected to the solution shower tray through the solution circulation pipeline to form a solution circulation. A filter screen for solution passing is arranged in the middle and upper part of the solution filter cartridge to realize high-position liquid inlet. The refrigerant reactor comprises a refrigerant tank, a refrigerant water shower tray, a refrigerant falling film heat exchanger, a refrigerant pump and a refrigerant circulation pipeline. The refrigerant water shower tray and the refrigerant falling film heat exchanger are sequentially arranged in the refrigerant tank from top to bottom, the refrigerant pump and the refrigerant circulation pipeline are arranged outside the refrigerant tank, the bottom end of the refrigerant tank is connected to the refrigerant pump inlet, and the refrigerant pump outlet is connected to the refrigerant water shower tray through the refrigerant circulation pipeline to form a refrigerant circulation; The solution tank is connected to the top of the refrigerant tank through a steam pipeline; The working stages of the three-phase absorption heat storage system include a heat charging stage and a heat releasing stage. The heat releasing stage can realize a heating function, a hot water making function or a cooling function.

2. The three-phase absorption heat storage system according to claim 1, characterized in that: A solution valve is arranged on the connecting pipe between the solution filter cartridge and the solution pump; a generator inlet valve is arranged at the inlet of the solution shower tray on the solution circulation pipe; a refrigerant water shower tray valve is arranged on the connecting pipe between the refrigerant tank and the refrigerant pump; and an energy storage stop valve is arranged on the steam pipe between the solution tank and the refrigerant tank.

3. The three-phase absorption heat storage system according to claim 1, characterized in that: During the heat charging stage, hot water and cooling water are respectively introduced into the solution falling film heat exchanger and the refrigerant falling film heat exchanger tubes, the solution circulation runs, and the refrigerant water circulation does not run. In the solution circulation, the solution passes through the solution filter cartridge, the solution pump, the solution shower tray and the solution falling film heat exchanger in sequence, absorbs the heat of the hot water in the solution falling film heat exchanger tube, and the generated refrigerant vapor enters the refrigerant tank through the steam pipe and condenses into liquid refrigerant, and the released condensation heat is taken away by the cooling water.

4. The three-phase absorption heat storage system according to claim 1, characterized in that: In the heating function or hot water making function in the heat release stage, heated water and low-temperature water are respectively introduced into the solution falling film heat exchanger and the refrigerant falling film heat exchanger tubes, and the solution circulation and the refrigerant circulation are operated simultaneously. The liquid refrigerant passes through the refrigerant pump, the refrigerant water shower tray and the refrigerant falling film heat exchanger in turn, absorbs the heat of the low-temperature water in the refrigerant falling film heat exchanger tube and evaporates. The gaseous refrigerant enters the solution tank through the steam pipe and is finally absorbed by the solution. The released heat is taken out by the heated water.

5. The three-phase absorption heat storage system according to claim 1, characterized in that: Under the refrigeration function in the heat release stage, cooling water and low-temperature water are respectively introduced into the solution falling film heat exchanger and the refrigerant falling film heat exchanger tubes, and the solution circulation and the refrigerant circulation are operated simultaneously. The liquid refrigerant passes through the refrigerant pump, the refrigerant water shower tray and the refrigerant falling film heat exchanger in turn, absorbs the heat of the low-temperature water in the refrigerant falling film heat exchanger tube and evaporates, thereby reducing the temperature of the low-temperature water to realize refrigeration output, and the solution tank is cooled by the cooling water in the solution falling film heat exchanger tube.

6. The three-phase absorption heat storage system according to claim 1, characterized in that: The three-phase absorption heat storage system also includes a refrigerant bypass pipe and a flushing bypass pipe; the refrigerant bypass pipe connects the refrigerant circulation pipe and the solution pump, the lower end of the flushing bypass pipe connects the solution pump inlet, and the upper end connects the upper end of the solution circulation pipe; after the heat charging / discharging stage, a small amount of refrigerant water is drawn from the refrigerant tank into the solution pump and the solution circulation pipe, the refrigerant water circulates between the solution pump, the solution circulation pipe and the flushing bypass pipe, and dilutes the concentrated solution remaining therein, and the diluted solution is finally pumped to the solution shower tray and the solution falling film heat exchanger for flushing, and enters the solution tank, thereby avoiding crystallization of the solution in the solution pump and the solution circulation pipe after cooling.

7. The three-phase absorption heat storage system according to claim 6, characterized in that: A refrigerant bypass valve is arranged on the refrigerant bypass pipe; a lower valve is arranged at the lower end of the flushing bypass pipe, and an upper valve is arranged at the upper end of the flushing bypass pipe; when the system is in normal operation at the heat charging or heat releasing stage, in order to prevent the solution from entering the flushing bypass pipe and causing crystallization blockage, the upper valve and the lower valve need to be closed; when the system is flushed, in order to circulate and dilute the flushing refrigerant water with the residual concentrated solution, the upper valve and the lower valve need to be opened; when the system is flushed, in order to empty the residual solution in the flushing bypass pipe, the upper valve needs to be closed and the lower valve opened.

8. The three-phase absorption heat storage system according to claim 1, characterized in that: The solution reactor also includes a heating device, which is arranged inside the solution filter cartridge and is used to melt crystals at the outlet of the solution tank before the exothermic stage of system operation or at the late stage of the heat charging stage.

9. The three-phase absorption heat storage system according to claim 8, characterized in that: The heating device is an electric heating rod, a blind pipe is installed in the solution filter cartridge, and the electric heating rod is inserted in the blind pipe.

10. The three-phase absorption heat storage system according to claim 1, characterized in that: Two solution filter cartridges are vertically arranged in the solution tank, one of which is provided with a short filter screen to achieve high-position liquid inlet, and the other is provided with a long filter screen, the bottom of the long filter screen is lower than the bottom of the short filter screen, and is used to achieve liquid inlet after the solution is reduced.

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