A kitchen oil fume heat recovery system for fresh air preheating or precooling

Abstract

This application discloses a kitchen fume heat recovery system for preheating or precooling fresh air, including a heat recovery coil installed in the exhaust duct and a fresh air heat exchange coil installed in the fresh air intake duct. The exhaust duct and the fresh air heat exchange coil form a heat exchange circulation pipeline through a connecting pipe. A three-way valve is installed on the heat exchange circulation pipeline to connect to a water supply pipe. A flow meter is installed on the water supply pipe. A circulation pump is installed on the heat exchange circulation pipeline, and shut-off valves are installed at the inlet and outlet of the circulation pump. A drain pipe is also installed on the heat exchange circulation pipeline, and a shut-off valve is installed on the drain pipe. This system can achieve fresh air preheating in winter and fresh air precooling in summer with the same circulation pipeline. By shutting off the valves before and after the circulation pump and opening the valve on the drain pipe, the mode can be switched from "heat recovery circulation" to "branch direct cooling", making it a multi-functional system. In addition, the system is compatible with existing kitchens, has a simple overall structure, is easy to install, and has low maintenance and operating costs.

Description

Technical Field

[0001] This application relates to the field of kitchen fume heat recovery technology, and in particular to a kitchen fume heat recovery system capable of preheating kitchen fresh air in winter and precooling it in summer. Background Technology

[0002] Kitchen exhaust fumes can reach temperatures of around 100℃, and can even reach 150℃. Traditionally, these fumes are simply discharged directly, resulting in significant energy waste and thermal pollution. Kitchen heat recovery is a crucial component of building energy efficiency; effectively utilizing kitchen waste heat is essential for reducing building energy consumption.

[0003] Chinese invention patent CN106989426A discloses a low-temperature flue gas heat recovery and heat exchange device based on micro heat pipe technology, which includes an insulating shell, a micro heat pipe array, and a partition. The partition has equidistant slits, and multiple vertical micro heat pipe arrays pass through the slits in the partition and are equidistantly arranged inside the insulating shell. The partition divides the gaps between the micro heat pipe arrays into upper and lower layers. The upper layer is a heat exchange layer, and the lower layer is a heat recovery layer. The evaporation section of the micro heat pipe array is located in the heat recovery layer, and the condensation section of the micro heat pipe array is located in the heat exchange layer. The micro heat pipe array transfers heat from the low-temperature flue gas passing through the heat recovery layer to the heat exchange layer, thereby heating the air passing through the heat exchange layer and realizing the heat exchange process. Its working principle is as follows: The exhaust fan is connected to the exhaust vent on the inlet side of the heat recovery layer, and the ventilation fan is connected to the heat exchange vent on the inlet side of the heat exchange layer. The exhaust fan introduces low-temperature flue gas or fumes from the kitchen and other environments into the lower heat recovery layer. As the low-temperature flue gas or fumes are discharged to the outside through each heat exchange channel, they come into full contact with the granular protrusions on the inner wall of the heat exchange channel. The heat in the flue gas is transferred to the micro heat pipe array connected to the heat exchange channel through the heat exchange channel. Since the heat recovery layer corresponds to the evaporation section of the micro heat pipe array, the micro heat pipe array uses the principles of heat conduction and phase change heat transfer to transfer heat from the lower heat recovery layer to the upper heat exchange layer through the internal working fluid flow and phase change. In the heat exchange layer, the heat is transferred to the fresh air introduced into the room by the ventilation fan through the heat exchange channel, thereby heating the fresh air and completing the entire heat exchange process.

[0004] Although the aforementioned literature-disclosed schemes can recover heat through phase change heat transfer, they can only perform single heating and cannot achieve fresh air pre-cooling in summer. At the same time, micro heat pipes need to be precisely matched with partitions and heat exchange channels, resulting in high processing and maintenance costs. Furthermore, the heat exchange surface needs to be regularly coated with a biological oil-separating film, otherwise it is prone to clogging.

[0005] In addition, Chinese utility model patent CN209325870U discloses a kitchen oil fume heat recovery and storage system for high-rise residential buildings. This system uses a copper tube-stainless steel finned heat exchanger installed in the exhaust pipe of each household to uniformly recover heat to a hot water storage tank. This system is suitable for centralized renovation of the entire building, but it relies on the main air duct, water pump, and hot water storage tank, resulting in a large initial investment. Furthermore, the small fin spacing makes it prone to oil accumulation, requiring regular cleaning of the oil collection box, and the maintenance workload increases significantly with the number of floors.

[0006] Therefore, it is evident that existing technical solutions for kitchen heat recovery generally suffer from the following shortcomings:

[0007] 1. It has a single function, only able to recover heat in winter, and does not consider the pre-cooling needs in summer;

[0008] 2. The structure is complex, maintenance is frequent, or centralized renovation is required, making it difficult to deploy quickly in existing kitchens.

[0009] Therefore, existing kitchen heat recovery solutions still have many shortcomings, and it is necessary to propose a new technical solution to solve the above-mentioned technical problems. Utility Model Content

[0010] This application provides a kitchen oil fume heat recovery system for preheating or precooling fresh air, in order to solve the problems of existing kitchen heat recovery devices having complex structures, high maintenance costs, and limited functionality, which can only achieve preheating of fresh air in winter.

[0011] To achieve the above objectives, this application provides the following technical solution:

[0012] This application provides a kitchen fume heat recovery system for preheating or precooling fresh air, including a heat recovery coil installed in the exhaust duct and a fresh air heat exchange coil installed in the fresh air intake duct. The inlet end of the heat recovery coil is connected to a water supply pipe and the outlet end of the fresh air heat exchange coil via a three-way valve. The outlet end of the heat recovery coil is connected to the inlet end of a circulation pump, and the inlet end of the fresh air heat exchange coil is connected to the outlet end of the circulation pump. Valves are respectively installed at the inlet and outlet ends of the circulation pump. The heat recovery coil and the fresh air heat exchange coil constitute a heat exchange circulation pipeline, and a drain pipe with a valve is installed on the drain pipe. The heat recovery coil is used to recover the heat of the fumes and heat exchange and raise the temperature of the liquid inside the coil. The circulation pump is used to circulate the liquid in the heat exchange circulation pipeline. The fresh air heat exchange coil can preheat the fresh air through the heat exchange circulation liquid inside the coil, and the fresh air heat exchange coil can precool the fresh air through the liquid that has not been heat exchanged and circulated by the heat recovery coil.

[0013] Furthermore, in the above technical solution, the exhaust duct is connected to the fume hood of the range hood, and the heat recovery coil is installed at one end of the exhaust duct near the fume hood; the heat recovery coil is any one of a spiral coil, a serpentine coil, or a planar spiral coil.

[0014] Furthermore, the fresh air heat exchange coil is installed inside the fresh air inlet duct of the kitchen fresh air unit; the fresh air heat exchange coil is any one of a spiral coil, a serpentine coil, or a planar spiral coil.

[0015] Furthermore, the outlet end of the heat recovery coil is connected to the inlet end of the circulating pump via a first connecting pipe, and a first valve is installed on the first connecting pipe; the inlet end of the fresh air heat exchange coil is connected to the outlet end of the circulating pump via a second connecting pipe, and a second valve is installed on the second connecting pipe.

[0016] Furthermore, the drain pipe is installed on the second connecting pipe, and the drain pipe is located between the second valve and the inlet end of the fresh air heat exchange coil, and a third valve is installed on the drain pipe.

[0017] Furthermore, a flow meter is installed on the water supply pipe.

[0018] Compared with the prior art, this application has at least the following beneficial effects:

[0019] Based on further analysis and research of existing technologies, this application recognizes that existing kitchen heat recovery devices are complex in structure, have high maintenance and operating costs, and only recover heat for preheating fresh air in winter, resulting in a single function. Therefore, this application provides a multi-functional kitchen fume heat recovery system, mainly composed of two heat exchange coils, a circulation pump, and multiple pipe valves. It can achieve both winter fresh air preheating and summer fresh air precooling using the same circulation pipeline without replacing or adding components. The mode switching from "heat recovery circulation" to "branch direct cooling" can be achieved by closing the valves before and after the circulation pump and opening the valve on the drain pipe, reducing energy consumption for summer fresh air precooling. Furthermore, the kitchen fume heat recovery system provided by this application is compatible with existing kitchens; the coil structure can be directly inserted into existing exhaust ducts and fresh air intake ducts without requiring centralized modification of the building's flue or main air duct. Moreover, the kitchen fume heat recovery system provided by this application has a simple structure and low manufacturing, installation, and maintenance costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concepts disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, and size ratios of certain units (components).

[0021] Figure 1 This is a schematic diagram of the system architecture of the kitchen fume heat recovery system provided in this application in one embodiment.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Exhaust duct; 2. Heat recovery coil; 3. Exhaust hood; 4. Water supply pipe; 5. Flow meter; 6. Three-way valve; 7. First valve; 8. Circulation pump; 9. Second valve; 10. Third valve; 11. Drain pipe; 12. Fresh air intake duct; 13. Fresh air heat exchange coil; 14. Kitchen fresh air unit; 15. Fresh air outlet. Detailed Implementation

[0024] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "comprising," "including," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0026] The terms used in this application, such as "upper," "lower," "left," "right," and "middle," are generally used to facilitate intuitive understanding by referring to the accompanying drawings, and are not absolute limitations on the positional relationships in the actual product. Changes in these relative positional relationships, without departing from the technical concept disclosed in this application, should also be considered within the scope of this application.

[0027] Based on research into current kitchen heat recovery solutions, the inventors recognized that these solutions generally suffer from complex structures, high maintenance costs, and difficulties in rapid retrofitting into existing kitchens. Furthermore, existing kitchen heat recovery solutions only recover heat in winter to preheat fresh air, offering limited functionality. Moreover, the inventors acknowledged that current kitchen heat recovery methods do not consider the issue of pre-cooling fresh air in summer, especially in the current design of high-rise residential units where kitchen areas are relatively small. In summer, cooking requires closing the kitchen door and relying on fresh air for pre-cooling, resulting in a considerable amount of fresh air needed and significant power consumption for pre-cooling.

[0028] Therefore, the inventors have developed a kitchen fume heat recovery system for preheating or precooling fresh air. This system primarily connects the exhaust duct to the fresh air duct via pipe components such as coils, a circulating pump, and valves. Only tap water needs to be added to the coils. In winter, the system can preheat fresh air through waste heat recovery from the fumes, and in summer, it can precool fresh air by controlling the opening and closing of the pipe valves. This multi-functional system is flexible in use and not limited by space or fan installation location. The system architecture and usage method of the kitchen fume heat recovery system for preheating or precooling fresh air provided in this application are described in detail below.

[0029] See Figure 1 The kitchen fume heat recovery system for preheating or precooling fresh air provided in this application mainly includes: heat recovery coil 2, fresh air heat exchange coil 13, connecting pipe connecting the two coils, circulation pump 8 and multiple valves installed on the connecting pipe, as well as water supply pipe 4 and drain pipe 11 installed on the connecting pipe.

[0030] Specifically, the heat recovery coil 2 is installed inside the exhaust duct 1, and the fresh air heat exchange coil 13 is installed inside the fresh air intake duct 12. The inlet end of the heat recovery coil 2 is connected to the water supply pipe 4 and the outlet end of the fresh air heat exchange coil 13 respectively through a three-way valve 6. The outlet end of the heat recovery coil 2 is connected to the inlet end of the circulation pump 8, and the inlet end of the fresh air heat exchange coil 13 is connected to the outlet end of the circulation pump 8. Valves are installed at the inlet and outlet ends of the circulation pump 8. The heat recovery coil 2 and the fresh air heat exchange coil 13 constitute a heat exchange circulation pipeline. A drain pipe 11 is installed on the heat exchange circulation pipeline, and a valve is installed on the drain pipe 11. The heat recovery coil 2 is used to recover the heat of the fumes and heat exchange and heat up the liquid in the pipe. The circulation pump 8 is used to realize the circulation of the liquid in the heat exchange circulation pipeline. The fresh air heat exchange coil 13 can preheat the fresh air through the heat exchange circulation liquid in the pipe, and the fresh air heat exchange coil 13 can precool the fresh air through the liquid that has not been heat exchanged and circulated by the heat recovery coil 2.

[0031] The kitchen fume heat recovery system for fresh air preheating or precooling provided by the above technical solution can achieve winter fresh air preheating and summer fresh air precooling with the same set of circulation pipelines without replacing or adding / subtracting components. By shutting off the valves before and after the circulation pump 8 and opening the valve on the drain pipe 11, the mode switch from "heat recovery circulation" to "branch direct cooling" can be realized, reducing the energy consumption of fresh air precooling in summer. In addition, the kitchen fume heat recovery system provided in this application mainly consists of two heat exchange coils, a circulation pump 8, a three-way valve 6 and multiple two-way valves, with a simple structure and relatively low manufacturing, installation and maintenance costs. Moreover, the kitchen fume heat recovery system provided in this application can be compatible with existing kitchens. The coil structure can be directly inserted into the existing exhaust fume pipe 1 and fresh air inlet pipe 12 without centralized renovation of the building flue or main air duct.

[0032] In the above technical solution, the exhaust fume pipe 1 is connected to the exhaust fume hood 3 of the range hood. The heat recovery coil 2 is installed at one end of the exhaust fume pipe 1 close to the exhaust fume hood 3. After the fume is drawn up, it directly exchanges heat with the liquid medium (preferably tap water, which is inexpensive and easy to obtain) in the heat recovery coil 2 to achieve fume heat recovery.

[0033] In the above technical solution, the fresh air heat exchange coil 13 is installed in the fresh air inlet pipe 12 of the kitchen fresh air unit 14.

[0034] The heat recovery coil 2 and the fresh air heat exchange coil 13 in this application can adopt any one of a rectangular coil, a serpentine coil or a planar spiral coil. In a specific manufacturing and installation, the heat recovery coil 2 can be composed of multiple layers of rectangular coils, serpentine coils or planar spiral coils, and the fresh air heat exchange coil 13 can also be composed of multiple layers of rectangular coils, serpentine coils or planar spiral coils.

[0035] It should be noted that the "rectangular coil" in this application refers to a coil whose pipeline reciprocates and folds back along a rectangular boundary, and the whole is in the shape of a "square" or "day" character; the "serpentine coil" in this application refers to a coil whose pipeline bends back and forth in a continuous U shape (or can be regarded as an S shape or a zigzag shape); the "planar spiral coil" in this application refers to an Archimedean spiral or an involute spiral coil, and the pipeline shrinks gradually from the outside to the inside, forming a continuous planar spiral structure coil.

[0036] In a specific installation and manufacturing, the outlet end of the heat recovery coil 2 is connected to the inlet end of the circulation pump 8 through a first connecting pipe, and a first valve 7 is installed on the first connecting pipe; the inlet end of the fresh air heat exchange coil 13 is connected to the outlet end of the circulation pump 8 through a second connecting pipe, and a second valve 9 is installed on the second connecting pipe. Both the first connecting pipe and the second connecting pipe adopt straight pipes. The above drain pipe 11 is arranged on the second connecting pipe, and the drain pipe 11 is located between the second valve 9 and the inlet end of the fresh air heat exchange coil 13, and a third valve 10 is arranged on the drain pipe 11.

[0037] In one specific embodiment, a pressure sensor can be installed at the outlet end of the circulating pump 8 of this application, and an automatic air vent valve can be installed at the highest point of the heat exchange circulation pipeline. When using the heat exchange circulation for the first time, the three-way valve 6 is opened to inject the heat exchange medium into the heat exchange circulation pipeline through the water supply pipe 4. During the injection process, the real-time flow rate can be monitored by the flow meter 5 on the water supply pipe 4. When the pressure stabilizes within the set range (e.g., 1.5 times the static pressure) after the circulating pump 8 is started, and the flow meter 5 shows no increase for 3 consecutive seconds, it is determined that the pipeline is full. At this time, the water supply pipe 4 can be shut off through the three-way valve 6 to stop the injection of water into the heat exchange circulation pipeline.

[0038] When using this application to preheat kitchen fresh air in winter, close the third valve 10 on the drain pipe 11, open the three-way valve 6 to inject heat exchange medium into the heat exchange circulation pipeline through the water supply pipe 4, and after the medium injection is completed, close the water supply pipe 4 through the three-way valve 6. Then, the system realizes heat exchange circulation under the action of the circulation pump 8, and uses the heat of kitchen fumes to preheat fresh air.

[0039] In summer, the circulating pump 8 can be turned off, the first valve 7 and the second valve 9 at the inlet and outlet of the circulating pump 8 can be shut off, the third valve 10 on the drain pipe 11 can be opened, and cold water can be injected into the fresh air heat exchange coil 13 through the water supply pipe 4 to pre-cool the fresh air.

[0040] To avoid water waste, a "closed-loop cold water circulation" mode can be achieved through structural improvements. Specifically, a cold water tank can be connected between the water supply pipe 4 and the drain pipe 11 (in household use, ice cubes can be added to an insulated water container to form a cold water tank; ice cubes can be made using a household refrigerator). A level gauge can be installed on the cold water tank for users to add water independently, or a float valve can be installed in the cold water tank for automatic external water replenishment. A cold water pump can be installed on the pipe connecting the cold water tank and the water supply pipe 4. That is, the water supply pipe 4, the fresh air heat exchange coil 13, the drain pipe 11, and the cold water tank constitute a cold water circulation pipeline, and the cold water pump provides the driving force for the reciprocating circulation of cold water in the cold water circulation pipeline.

[0041] In summary, this application provides a kitchen fume heat recovery system for preheating or precooling fresh air. It mainly connects the exhaust duct and the fresh air duct through pipe components such as coils, a circulating pump, and valves. Only tap water needs to be added to the coils. In winter, the fresh air can be preheated through the recovery of waste heat from the fumes, and in summer, the fresh air can be precooled by controlling the opening and closing of the pipe valves, making it a multi-functional system. Furthermore, the kitchen fume heat recovery system provided by this application has a simple structure and low manufacturing, installation, and maintenance costs. Moreover, the kitchen fume heat recovery system provided by this application is compatible with existing kitchens; the coil structure can be directly inserted into existing exhaust ducts and fresh air intake ducts without requiring centralized modification of the building's flue or main air duct.

[0042] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

[0043] The present application has been described in a relatively specific and detailed manner above through general descriptions and specific embodiments. It should be understood that, based on the technical concept of the present application, several conventional adjustments or further innovations can be made to these specific embodiments; however, as long as they do not depart from the technical concept of the present application, the technical solutions obtained by these conventional adjustments or further innovations also fall within the protection scope of the claims of the present application.

Claims

1. A kitchen fume heat recovery system for preheating or precooling fresh air, characterized in that, It includes a heat recovery coil (2) installed in the exhaust duct (1) and a fresh air heat exchange coil (13) installed in the fresh air intake duct (12); the inlet end of the heat recovery coil (2) is connected to the water supply pipe (4) and the outlet end of the fresh air heat exchange coil (13) respectively through a three-way valve (6); the outlet end of the heat recovery coil (2) is connected to the inlet end of the circulation pump (8); the inlet end of the fresh air heat exchange coil (13) is connected to the outlet end of the circulation pump (8); valves are respectively provided at the inlet and outlet ends of the circulation pump (8); the heat recovery coil (2) and the fresh air heat exchange coil (13) constitute a heat exchange circulation pipeline; a drain pipe (11) is provided on the heat exchange circulation pipeline; a valve is provided on the drain pipe (11); The heat recovery coil (2) is used to recover the heat of the oil fume and heat the liquid in the pipe. The circulation pump (8) is used to circulate the liquid in the heat exchange circulation pipeline. The fresh air heat exchange coil (13) can preheat the fresh air through the heat exchange circulation liquid in the pipe, and the fresh air heat exchange coil (13) can precool the fresh air through the liquid that has not been heat exchanged and circulated by the heat recovery coil (2).

2. The kitchen oil fume heat recovery system for preheating or precooling fresh air according to claim 1, characterized in that, The exhaust duct (1) is connected to the fume hood (3) of the range hood, and the heat recovery coil (2) is installed at one end of the exhaust duct (1) near the fume hood (3); The heat recovery coil (2) is any one of a spiral coil, a serpentine coil, or a planar spiral coil.

3. The kitchen oil fume heat recovery system for preheating or precooling fresh air according to claim 1, characterized in that, The fresh air heat exchange coil (13) is installed inside the fresh air inlet duct (12) of the kitchen fresh air unit (14); The fresh air heat exchange coil (13) is any one of a spiral coil, a serpentine coil, or a planar spiral coil.

4. The kitchen fume heat recovery system for preheating or precooling fresh air according to claim 1, characterized in that, The outlet end of the heat recovery coil (2) is connected to the inlet end of the circulating pump (8) through a first connecting pipe, and a first valve (7) is installed on the first connecting pipe; The inlet end of the fresh air heat exchange coil (13) is connected to the outlet end of the circulating pump (8) through a second connecting pipe, and a second valve (9) is installed on the second connecting pipe.

5. The kitchen fume heat recovery system for fresh air preheating or precooling according to claim 4, characterized in that, The drain pipe (11) is installed on the second connecting pipe, and the drain pipe (11) is located between the second valve (9) and the inlet end of the fresh air heat exchange coil (13). A third valve (10) is installed on the drain pipe (11).

6. The kitchen fume heat recovery system for fresh air preheating or precooling according to claim 1, characterized in that, A flow meter (5) is installed on the water supply pipe (4).

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