Absorption type defrosting system of waste heat recycling refrigerator

Abstract

The utility model discloses an absorption type refrigerator defrosting system of waste heat recycling belongs to refrigeration equipment technical field, and this system is by heat exchanger, heat exchange coil, defrosting coil, heat preservation device, three -way valve, circulating pump and control module composition, and the system passes through three -way valve and imports the heat exchanger to the waste heat fluid, and the antifreeze solution of closed circulation is heated, and the circulating pump drives the antifreeze solution to flow through the defrosting coil of arrangement in the evaporator outer wall, realizes the evaporator defrosting. This structure need not electric heating and energy -efficient, do not influence refrigeration cycle operation, and the antifreeze solution is completely isolated with refrigerant, and the system is safe and reliable.

Description

Technical Field

[0001] This application relates to the field of refrigerator refrigeration technology, specifically to an absorption-type refrigerator defrosting system that recovers and utilizes waste heat. Background Technology

[0002] Absorption refrigerators, as an environmentally friendly refrigeration device, have attracted attention due to their CFC-free and compressor-free operation. However, similar to traditional compression refrigerators, they also face the problem of evaporator frosting during operation. Evaporator frosting significantly reduces the heat exchange area and increases airflow resistance, leading to a decrease in heat exchange efficiency and cooling performance, ultimately affecting the user experience.

[0003] The defrosting methods commonly used in existing absorption refrigerators (such as natural defrosting when the refrigerator is off or semi-automatic heating defrosting) have drawbacks such as low efficiency, long cycles, or high energy consumption. Long-term use can easily lead to aggravated frost buildup, which restricts the further promotion and application of absorption refrigerators. Utility Model Content

[0004] In view of at least one of the above technical problems, the present invention provides an absorption-type refrigerator defrosting system for waste heat recovery and utilization.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A defrosting system for an absorption refrigerator that recovers and utilizes waste heat includes a heat exchanger, a heat exchange coil, a defrosting coil, an insulation device, a three-way valve, a circulation pump, and a control module. The heat exchange coil is located inside the heat exchanger, and its cavity is sealed and filled with an antifreeze solution. The defrosting coil is connected to the heat exchanger cavity through a pipeline, forming a closed circulation loop. The circulation pump is located on this loop. The inlet end of the three-way valve is connected to an external waste heat fluid source through the insulation device, its first outlet end is connected to a waste heat fluid discharge pipeline, and its second outlet end is connected to the inlet of the heat exchange coil.

[0007] The control module determines the evaporator surface temperature based on the evaporator temperature sensor signal to control the fluid distribution direction of the three-way valve and the start / stop of the circulation pump. When the three-way valve opens the first outlet end, the refrigerator only performs refrigeration circulation. When the three-way valve opens the second outlet end in defrost mode, the circulation pump is started simultaneously.

[0008] Preferably, when the defrosting system is only in the refrigeration cycle, the waste heat fluid flows sequentially through the insulation device, the heating coil inside the generator, the first outlet end of the three-way valve, and the discharge pipe connected to the first outlet end.

[0009] Preferably, the refrigeration cycle does not stop when the defrosting system starts defrosting. At this time, the waste heat fluid flows sequentially through the insulation device, the heating coil inside the generator, the second outlet end of the three-way valve, and the heat exchange coil.

[0010] Preferably, the defrosting coil is physically isolated from the refrigeration cycle system, and defrosts the frost layer on the evaporator surface by heat conduction, thus avoiding refrigerant contamination.

[0011] Preferably, the control module triggers the switching of the three-way valve when the evaporator temperature is lower than the preset frosting critical temperature, and the circulation pump is started synchronously after the switching. The control module is also used to control the three-way valve to switch back to the first outlet end and stop the circulation pump after defrosting has lasted for a preset time, or when the evaporator temperature rises to a preset exit temperature. The system exits the defrosting mode and restarts temperature monitoring.

[0012] Preferably, the circulation loop of the heat exchanger and the defrosting coil is a closed structure, filled with antifreeze solution and not exchanged with other fluids. The antifreeze solution has a low freezing point and good thermal conductivity, and is completely physically isolated from the waste heat fluid through the heat exchanger.

[0013] Preferably, the heat exchanger adopts a coaxial design, with the outer tube being a stainless steel cavity sealed and filled with antifreeze solution; the inner tube is a metal heat exchange coil, within which the waste heat fluid flows unidirectionally. This counter-current heat exchange design improves heat transfer efficiency, and the antifreeze solution circulates within the closed pipeline, achieving efficient heat transfer through the counter-current heat exchanger design. During defrosting, the antifreeze solution inside the heat exchanger does not directly contact or exchange with the external waste heat fluid.

[0014] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0015] This invention dynamically diverts waste heat fluid through a three-way valve. While maintaining the refrigeration cycle of the absorption refrigerator, it guides the waste heat fluid flowing through the generator heating coil to the heat exchanger, heating the closed-loop antifreeze solution within. Driven by a circulation pump, the high-temperature antifreeze solution flows through the defrosting coil on the outer wall of the evaporator to melt the frost layer. Compared with traditional electric heating solutions, this invention achieves deep recovery and utilization of low-grade waste heat, providing a defrosting solution that requires no electric heating, is highly energy efficient, and does not interfere with the main refrigeration cycle. At the same time, through the physically isolated secondary circuit design, it eliminates the risk of refrigerant contamination. Furthermore, it has a compact structure, strong versatility, and is suitable for various external heat source conditions. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the defrosting system provided in this embodiment of the utility model;

[0018] Figure 2 This is a schematic diagram of the defrosting system control principle provided in an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of the defrosting system structure is provided for an embodiment of this utility model;

[0020] Reference numerals: 1. Generator; 2. Distillation apparatus; 3. Condenser; 4. Throttling valve; 5. Evaporator; 6. Absorber; 7. Circulating pump; 8. Solution heat exchanger; 9. Insulation device; 10. Three-way valve; 11. Heat exchanger; 12. Defrosting coil; 13. Heating coil; 14. Solution pump; 15. Water pump; 16. Dilute liquid pipe; 17. Baffle; 18. Concentrated ammonia pipe; 19. Gas return pipe; 20. Liquid storage tank; 21. Heat exchange coil. Detailed Implementation

[0021] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] Unless otherwise specified, the unit modules (components, structures, mechanisms) or sensors involved in the following embodiments are all conventional commercially available products.

[0023] like Figure 2 As shown, the refrigeration core of the absorption refrigerator is a fully enclosed system. During the refrigeration cycle, the ammonia solution is heated by the heating coil 13 in the generator 1, and the resulting ammonia vapor enters the condenser 3 and condenses into liquid ammonia. The liquid ammonia enters the evaporator 5 through the concentrated ammonia pipe 18, where it evaporates and absorbs heat, producing a cooling effect. The evaporated ammonia and hydrogen mixture enters the storage tank 20, where the ammonia is absorbed. The unabsorbed hydrogen and other gases enter the absorber 6 for secondary absorption, and the resulting ammonia solution flows back to the generator 1, completing the cycle. This system operates based on the thermosiphon principle, where ammonia only needs to gain heat to evaporate from the solution.

[0024] Currently, absorption refrigerators face the challenge of evaporator frosting during operation. Similar to traditional refrigerators, evaporator frosting reduces the airflow area, increases flow resistance, and lowers evaporator heat exchange efficiency and cooling performance. Furthermore, existing defrosting methods for absorption refrigerators (such as automatic defrosting during shutdown or semi-automatic heating defrosting) are inefficient, have long cycles, or consume high energy. Long-term use can exacerbate the frosting problem, negatively impacting the user experience.

[0025] Therefore, this application provides a waste heat recovery absorption refrigerator defrosting system that uses external waste heat fluid as a heat source. By introducing a waste heat recovery defrosting module into the absorption refrigeration cycle system, the reuse of low-grade waste heat is realized, avoiding the high energy consumption problem of traditional electric heating defrosting, and the refrigeration cycle is not interrupted during defrosting.

[0026] To better understand the technical solution of this application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] A defrosting system for an absorption refrigerator that recovers and utilizes waste heat includes a heat exchanger 11, a heat exchange coil 21, a defrosting coil 12, an insulation device 9, a three-way valve 10, a circulation pump 7, and a control module. The inlet of the insulation device 9 is connected to an external waste heat fluid supply pipeline, and the outlet is connected to the inlet of the three-way valve 10. The inlet end of the three-way valve 10 is connected to the input pipeline of the insulation device 9, the first outlet end is connected to the waste heat fluid output pipeline, and the second outlet end is connected to the heat exchange coil 21. The heat exchange coil 21 is placed inside the heat exchanger 11. The defrosting coil 12 is connected to the heat exchanger 11 and fixed to the outer wall of the evaporator 5. The circulation pump 7 is located on the circulation loop of the defrosting coil 12.

[0029] The control module determines the temperature of the evaporator 5 based on the evaporator temperature sensor signal to control the fluid distribution direction of the three-way valve 10 and the start / stop of the circulation pump 7. When the three-way valve 10 opens the first outlet end, the refrigerator only performs refrigeration circulation; when the three-way valve 10 opens the second outlet end in defrost mode, the circulation pump 7 is started at the same time.

[0030] In this embodiment, when the defrosting system is only in the refrigeration cycle, the waste heat fluid flows sequentially through the heat preservation device 9, the heating coil 13 inside the generator 1, the first outlet end of the three-way valve 10, and the discharge pipe connected to the first outlet end.

[0031] In this embodiment, preferably, the refrigeration cycle does not stop when the defrosting system starts defrosting. At this time, the first outlet end of the three-way valve 10 is closed and the second outlet end is open. The waste heat fluid flows sequentially through the insulation device 9, the heating coil inside the generator 1, the second outlet end of the three-way valve 10, and the heat exchange coil 21. This design ensures uninterrupted refrigeration during defrosting, which is beneficial for maintaining a stable temperature inside the chamber.

[0032] In this embodiment, the defrosting coil is physically isolated from the refrigeration cycle system. The defrosting is achieved by heating the frost layer on the surface of the evaporator 5 through heat conduction, thus avoiding contamination of the refrigerant.

[0033] In this embodiment, the control module triggers the switching of the three-way valve 10 by real-time acquisition of the evaporator temperature through a temperature sensor and transmission of the signal to the control module. When the evaporator temperature is >-5℃, the three-way valve keeps the first outlet end open. When the evaporator temperature is ≤-5℃ and the duration is ≥30 minutes, it is determined that defrosting is required. The control module controls the three-way valve 10 to switch to the second outlet end and starts the circulation pump 7. The control module is also used to control the three-way valve to switch back to the first outlet end and stop the circulation pump after defrosting has lasted for 10 minutes or when the evaporator temperature rises to the preset exit temperature of 5℃. The system exits the defrosting mode and restarts temperature monitoring.

[0034] In this embodiment, the circulation loop of the heat exchanger 11 and the defrosting coil 12 is a closed structure, filled with antifreeze solution and not exchanged with other fluids, and is physically isolated from the waste heat fluid through the heat exchanger 11.

[0035] In this embodiment, the heat exchanger 11 adopts a shell-and-tube design. The outer tube is a 304 stainless steel cavity, sealed and filled with an antifreeze solution, which is a mixture of 85% ethylene glycol and 15% glycerol by mass. The inner tube is a copper heat exchange coil 21, in which the waste heat fluid flows unidirectionally. The counter-current heat exchange design improves heat transfer efficiency. The antifreeze solution circulates in the closed pipeline, and the counter-current heat exchange design of the heat exchanger 11 (copper inner tube and stainless steel outer tube) achieves efficient heat transfer while completely isolating it from external waste heat fluid and refrigerant. Defrosting is performed without direct contact or exchange with the antifreeze solution inside the heat exchanger.

[0036] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A waste heat recovery and utilization absorption refrigerator defrosting system, comprising a heat exchanger (11), a heat exchange coil (21), a defrosting coil (12), a heat preservation device (9), a three-way valve (10), a circulation pump (7), and a control module, characterized in that: The heat exchange coil (21) is located inside the heat exchanger (11), and the cavity of the heat exchanger (11) is sealed and filled with antifreeze solution. The defrosting coil (12) is connected to the cavity of the heat exchanger (11) through a pipeline, forming a closed loop of antifreeze solution. The circulation pump (7) is installed on this loop. The inlet end of the three-way valve (10) is connected to the external waste heat fluid supply pipeline through the heat insulation device (9). The first outlet end of the three-way valve (10) is connected to the waste heat fluid discharge pipeline, and the second outlet end is connected to the inlet of the heat exchange coil (21). When the system enters the defrosting mode, the three-way valve (10) opens the second outlet end, allowing the external waste heat fluid to flow through the heat exchange coil (21) to heat the antifreeze solution. The circulation pump (7) drives the antifreeze solution to flow through the defrosting coil (12) to heat and defrost the evaporator.

2. The waste heat recovery and utilization defrosting system for an absorption refrigerator according to claim 1, characterized in that, The control module is connected to the evaporator temperature sensor signal and is used to control the switching of the three-way valve (10) and the start and stop of the circulation pump (7) according to the temperature of the evaporator to achieve automatic defrosting.

3. The waste heat recovery and utilization absorption refrigerator defrosting system according to claim 1, characterized in that, The antifreeze solution circulation loop is a closed structure, and the internal antifreeze solution is isolated from the waste heat fluid and refrigerant.

4. The waste heat recovery and utilization absorption refrigerator defrosting system according to claim 1, characterized in that, The heat exchanger (11) adopts a sleeve structure, with the outer tube cavity sealed and filled with antifreeze solution, and the inner tube is a metal heat exchange coil (21), in which the waste heat fluid flows unidirectionally.

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