Solution concentration system based on parallel heat recovery and use method thereof

Abstract

The invention relates to the technical field of air conditioner cold and heat source corollary equipment, in particular to a solution concentration system based on parallel heat recovery and a use method thereof. The solution concentration system based on parallel heat recovery is composed of a heat pump heating internal circulation system and a solution concentration heat recovery system. The heat pump heating internal circulation system comprises two parts of water tanks which are respectively used for storing an anti-freezing solution to be concentrated and condensed water, and heat in the condensed water is pumped to the anti-freezing solution to be concentrated by utilizing a heat pump; the solution concentration heat recovery system conducts heat recovery on the flowback anti-freezing solution and the to-be-discharged condensate water so as to be used for heating the to-be-concentrated anti-freezing solution. According to the anti-freezing solution concentration device, steam is directly introduced into the lower portion of the second water tank from the upper portion of the first water tank, the steam condensation efficiency is higher, and meanwhile the first heat exchanger and the second heat exchanger which are arranged correspondingly start the input progress of the anti-freezing solution to be treated in time according to the anti-freezing solution flowback and condensate water discharging conditions; and a more efficient anti-freezing solution concentration effect is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of air conditioning cold and heat source supporting equipment, specifically involving a solution concentration system based on parallel heat recovery and its usage method, to achieve efficient solution concentration, so as to better ensure the normal operation of the heat source tower system in winter. Background Technology

[0002] Heat source tower technology can effectively replace traditional heat sources such as oil and gas boilers in winter, reducing fossil energy consumption and significantly reducing building carbon emissions in winter. At the same time, compared with the commonly used green alternative heat source air-cooled heat pump, the energy efficiency ratio of heat source tower heat pumps is generally more than 20% higher in winter and summer. Therefore, heat source towers not only meet the current carbon reduction needs, but also achieve energy-saving and high-efficiency application effects.

[0003] However, during winter operation, the antifreeze solution in the heat source tower continuously absorbs moisture from the air, causing its concentration to decrease. It must be restored through a concentration process; otherwise, three major problems will arise:

[0004] (1) Increased freezing point leads to the risk of freezing. The core function of antifreeze is to prevent freezing. The lower the concentration, the higher the freezing point (e.g., the freezing point of a 25 vol% ethylene glycol solution is about -15℃, while the freezing point is only -8℃ after dilution to 15 vol%). If not concentrated, the antifreeze is prone to freezing in the heat source tower or pipeline during low winter temperatures, directly damaging the equipment.

[0005] (2) The heat exchange efficiency decreases and the heating capacity is reduced. The concentration of antifreeze is directly related to the thermal conductivity. The heat absorption capacity of the diluted solution is weakened, which will lead to a decrease in the heating power of the heat pump unit, which cannot meet the heating needs of the building and may even increase energy consumption.

[0006] (3) Accelerates equipment corrosion and increases maintenance costs. Most antifreeze solutions require the addition of corrosion inhibitors. Dilution of the concentration will disrupt the balance of the corrosion inhibitors, making metal pipes and heat source tower packings more susceptible to corrosion, shortening equipment lifespan, and increasing maintenance frequency and costs.

[0007] Currently, solution concentration technologies include heating concentration, membrane concentration, vacuum concentration, and vacuum-heating concentration. Heating concentration is the most widely used due to its simplicity and reliability, but it consumes a large amount of heat, significantly reducing the system's energy efficiency. Membrane concentration is theoretically feasible and very energy-efficient, but it requires osmotic pressure to be generated across the membrane. Currently, no suitable osmotic membrane material has been found, and osmotic membranes are often expensive. Vacuum concentration requires maintaining a very high vacuum level and has low concentration efficiency, making it difficult to meet the concentration requirements of antifreeze in heat source tower systems. Vacuum-heating concentration is a combination of heating and vacuum concentration, which can reduce energy consumption to some extent, but it also presents the challenge of maintaining a high vacuum level.

[0008] Chinese utility model patent CN218392267U discloses a heat recovery antifreeze concentration technology. The device includes a solution tank, an evaporation chamber, and a condensation chamber. The antifreeze outlet of the solution tank is connected to the antifreeze inlet of the evaporation chamber via a first pipe. The first antifreeze outlet of the evaporation chamber is connected to the first antifreeze inlet of the solution tank via a second pipe. The steam outlet of the evaporation chamber is connected to the steam inlet of the condensation chamber via a third pipe. The first condensate outlet of the condensation chamber is connected to a fourth pipe. A heat pump unit is also included, with its heating section located in the evaporation chamber and its cooling section located in the condensation chamber. However, this device uses a series heat exchanger for heat recovery, resulting in temperature gradient losses and insufficient heat recovery. Furthermore, its condenser cooling section is located at the steam outlet, meaning it can only cool the steam. Chinese invention patent CN108721924B discloses preheating a dilute solution using ejected steam, but this adds an ejector circulating water tank and other devices, increasing system complexity and floor space. Summary of the Invention

[0009] The purpose of this invention is to overcome the problem that the heat exchange efficiency of antifreeze in the existing antifreeze concentration technology has room for optimization when the antifreeze is concentrated and returned to the antifreeze tank, and to provide a solution concentration system based on parallel heat recovery and its usage method.

[0010] In a first aspect, the present invention provides a solution concentration system based on parallel heat recovery, which optimizes the problem of low heat exchange efficiency during solution transportation by antifreeze tank and concentration device, and is used to achieve antifreeze concentration treatment with lower energy consumption and higher efficiency, reduce energy consumption in the antifreeze concentration process, and enhance the overall reliability of the concentration device system.

[0011] A solution concentration system based on parallel heat recovery consists of a heat pump heating internal circulation system and a solution concentration heat recovery system.

[0012] The heat pump heating internal circulation system includes a first water tank, a second water tank, a heat pump main unit, and a steam pipe; The heat pump unit includes a compressor, a condenser heater, and an evaporator cooler; The condenser heater is located near the bottom of the first water tank; the evaporator cooler is located near the bottom of the second water tank. The compressor is connected to the condenser heater and the evaporator cooler through pipelines to form a heat pump circulation loop; One end of the steam pipe is connected to the top or top side of the first water tank, and the other end is connected to the bottom or bottom side of the second water tank. The solution concentration heat recovery system includes a first solution pump, a second solution pump, a condensate pump, a first heat exchanger, a second heat exchanger, a first inlet pipe, a second inlet pipe, a return pipe, and a condensate pipe; The inlet of the first solution pump is connected to the antifreeze tank, and the outlet of the first solution pump is connected to the main antifreeze pipe to be treated. The main antifreeze pipe to be treated is connected to both the first inlet pipe and the second inlet pipe via a tee. A control valve is provided on the second inlet pipe. Both the first inlet pipe and the second inlet pipe are connected to the top or top side of the first tank.

[0013] One end of the return pipe is connected to the bottom or side of the first water tank, and the other end of the return pipe is used to connect to the antifreeze tank. The second solution pump is installed on the return pipe; The second heat exchanger is used to exchange heat between the first inlet pipe and the return pipe; One end of the condensate pipe is connected to the bottom or side of the second water tank, and the other end of the condensate pipe is used to discharge condensate. The condensate pump is installed on the condensate pipeline; The first heat exchanger is used to exchange heat between the second liquid inlet pipe and the condensate pipe.

[0014] In the solution concentration system based on parallel heat recovery of the present invention, steam is directly introduced from the upper part of the first water tank to the lower part of the second water tank, resulting in higher steam condensation efficiency. At the same time, the first and second heat exchangers, which are respectively set, start / adjust the input progress of the antifreeze to be treated in a timely manner according to the antifreeze backflow and condensate discharge, so as to achieve a more efficient antifreeze concentration effect.

[0015] Furthermore, the first water tank is equipped with at least one of the following: a first pressure relief valve, a first pressure gauge, a first level gauge, a first thermometer, and a first drain pipe.

[0016] Furthermore, the second water tank is equipped with at least one of the following: a second pressure relief valve, a second pressure gauge, a second thermometer, a second drain pipe, and a second level gauge.

[0017] Furthermore, the control valve is an electrically operated regulating valve.

[0018] Furthermore, a first check valve is installed on the main antifreeze pipe to be treated.

[0019] Furthermore, a second check valve is provided on the return pipeline. Preferably, the second check valve is located near the outlet of the second solution pump.

[0020] Furthermore, a first concentration monitoring device is installed on the main antifreeze pipe to be treated, and a second concentration monitoring device is installed on the return pipe.

[0021] Furthermore, a gas flow meter is installed on the steam pipe.

[0022] Furthermore, the first inlet pipe merges with the second inlet pipe and is then connected to the first water tank.

[0023] In a second aspect, the present invention provides a method for concentrating antifreeze using the above-mentioned device, which better controls the high-efficiency operation of the concentration device system and completes the antifreeze concentration process with lower energy consumption.

[0024] A method for concentrating antifreeze, using the above-mentioned solution concentration system based on parallel heat recovery, includes the following steps: S1. Use the first solution pump to deliver the antifreeze to be treated to the first water tank until the liquid level in the first water tank reaches the first preset height; S2. Start the heat pump heating internal circulation system to heat the solution in the first water tank, so that the water evaporates and enters the second water tank and is condensed into liquid; S3. When the solution concentration in the first water tank reaches the first preset concentration, the second solution pump is started for backflow; at the same time, the first solution pump is started to transport the antifreeze to be treated to the first water tank through the first inlet pipe, and the second heat exchanger is started for heat recovery. When the liquid level in the second water tank reaches the second preset height, the condensate pump is started to discharge the condensate in the second water tank; at the same time, the control valve is opened, and the antifreeze to be treated is transported to the first water tank through the second inlet pipe using the first solution pump, and the first heat exchanger is started to recover heat. S4. Repeat S1 or S3 to ensure that the liquid level in the first water tank can submerge the condenser heater and does not exceed the first preset height; keep the heat pump heating internal circulation system working continuously in S2 until all the antifreeze to be processed is concentrated.

[0025] During startup, the antifreeze to be treated is first pumped to the first water tank. The compressor is then turned on, and the antifreeze is heated by the high-temperature, high-pressure refrigerant pipeline into the condenser heater. The steam enters the second water tank and contacts the evaporative cooler, where it is cooled and liquefied by the low-temperature, low-pressure refrigerant flowing through the evaporative cooler, thus achieving the first stage of steam condensation. Once the condensate in the second water tank reaches a certain volume, it can be used to efficiently cool the steam. After the overall circulation of the concentration unit stabilizes, the heat from the return liquid in the first water tank and the condensate discharged from the second water tank can be efficiently recovered, achieving the highest efficiency in antifreeze concentration.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the solution concentration system based on parallel heat recovery of the present invention, steam is directly introduced from the upper part of the first water tank to the lower part of the second water tank, resulting in higher steam condensation efficiency. Simultaneously, the separately installed first and second heat exchangers activate the input progress of the antifreeze to be processed in a timely manner according to the antifreeze backflow and condensate discharge situation. Through fluid flow design, the energy contained in the concentrated solution and condensate transported by the backflow pipeline is recovered and used to preheat the dilute solution, reducing heating demand, decreasing heat pump energy consumption, and improving the overall energy efficiency of the system.

[0027] 2. Compared to existing technologies, the device system of this invention achieves high-efficiency cooling steam for condensate during stable operation, while simultaneously recovering heat from both the concentrated antifreeze and condensate separately, avoiding interference from heat recovery on a single pipeline. By using parallel heat exchangers, heat exchange is achieved between the concentrated return solution and the dilute solution to be concentrated, and between the condensate and the dilute solution to be concentrated. Compared to series heat exchanger schemes, the larger heat exchange temperature difference in the parallel scheme ensures effective heat recovery and increases the amount of heat recovered.

[0028] 3. The solution concentration system based on parallel heat recovery of the present invention extracts the heat generated by water vapor condensation in the condensate tank on the evaporation side of the heat pump circulation and uses it for heating and concentration on the condensation side in the solution concentration tank, thereby realizing the effective transfer of latent heat in water vapor and reducing the temperature difference between the condensation side and the evaporation side, which is more conducive to the efficient operation of the heat pump.

[0029] 4. The concentration method of this invention utilizes a concentration device system. During startup, the antifreeze to be treated is pumped to the first water tank. It then enters the condenser heater through a high-temperature, high-pressure refrigerant pipeline to heat the antifreeze. Steam enters the bottom of the second water tank, contacting the evaporative cooler or the low-temperature concentrated antifreeze in the second water tank, where it is cooled and liquefied, achieving steam condensation treatment in the first water tank. The steam evaporating from the first water tank is primarily water vapor, which is condensed into liquid in the second water tank. Especially when the condensate in the second water tank reaches a certain volume, the condensate can be used to efficiently cool the steam. The evaporative cooler first cools the condensate in the second water tank (even to the point of supercooling) to reserve cooling capacity. When the steam enters, it is rapidly and efficiently cooled by the condensate. After the overall circulation of the concentration device stabilizes, the heat from the return liquid in the first water tank and the condensate discharged from the second water tank can be efficiently recovered, achieving the highest efficiency in antifreeze concentration treatment. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the system principle of the solution concentration system based on parallel heat recovery in Embodiment 1 of the present invention.

[0031] Marked in the image: 1-Second heat exchanger, 2-First heat exchanger, 3-First water tank, 4-Condensation heater, 5-First pressure relief valve, 6-First pressure gauge, 7-First level gauge, 8-First thermometer, 9-First drain pipe; 10-Steam pipe, 11-Evaporative cooler, 12-Second water tank, 13-Second pressure relief valve, 14-Second pressure gauge, 15-Second thermometer, 16-Second drain pipe, 17-Second liquid level gauge, 18-Gas flow meter, 19-Heat pump main unit; 20-Compressor, 21-Expansion valve, 22-First solution pump, 23-Second solution pump, 24-Condensate pump, 25-Main antifreeze pipe to be treated, 26-First inlet pipe, 27-Return pipe, 28-Condensate pipe, 29-Second inlet pipe; 30-High temperature and high pressure refrigerant pipeline, 31-Hot medium return pipeline, 32-Cold medium return pipeline, 33-Low temperature and low pressure refrigerant pipeline, 34-Second check valve, 35-First check valve, 36-First concentration monitoring device, 37-Second concentration monitoring device, 38-Control valve. Detailed Implementation

[0032] Concentration of antifreeze is a key factor in the long-term reliable and efficient operation of heat pump units during the heating season. Existing heating and concentration technologies involve heating the diluted solution in a regenerator to increase its temperature and water vapor partial pressure, thereby accelerating water evaporation and the separation of water molecules in the solution. Essentially, it evaporates water from the solution as water vapor, which is then discharged, thus increasing the solution concentration. The heat source can be external, such as a heat pump or electric heating, requiring additional electrical energy and reducing system energy efficiency. Traditional heating methods are energy inefficient, resulting in high energy consumption.

[0033] Chinese utility model patent CN218392267U discloses a heat recovery antifreeze concentration technology. The device includes a solution tank, an evaporation chamber, and a condensation chamber. The antifreeze outlet of the solution tank is connected to the antifreeze inlet of the evaporation chamber via a first pipe. The first antifreeze outlet of the evaporation chamber is connected to the first antifreeze inlet of the solution tank via a second pipe. The steam outlet of the evaporation chamber is connected to the steam inlet of the condensation chamber via a third pipe. The first condensate outlet of the condensation chamber is connected to a fourth pipe. A heat pump unit is also included, with its heating section located in the evaporation chamber and its cooling section located in the condensation chamber. This system heats the antifreeze using a heat pump and recovers heat from the condensate, significantly improving the efficiency of antifreeze concentration and reducing energy consumption compared to traditional technologies.

[0034] However, the heat recovery of this device using series heat exchangers suffers from temperature gradient losses, resulting in insufficient heat recovery. Furthermore, placing the evaporative cooler at the steam outlet of the steam delivery pipeline to cool the steam means that most of the evaporative cooler is in contact with the air, which has a low specific heat capacity, thus limiting the efficiency of the heat pump.

[0035] This invention provides a novel solution concentration system based on parallel heat recovery, which consists of a solution concentration heat recovery system and a heat pump heating internal circulation system.

[0036] The solution concentration heat recovery system includes a first solution pump, a second solution pump, a condensate pump, a second heat exchanger (used for heat exchange and heat recovery during concentrated solution return), a first heat exchanger (used for heat exchange and heat recovery during condensate discharge), a solution concentration tank (first water tank), and a condensate tank (second water tank). The first solution pump is connected to the second heat exchanger via a branch of the main dilute solution (antifreeze to be treated) pipe. The first solution pump is also connected to the first heat exchanger via a branch of the main dilute solution pipe. Dilute solution pipes one and two merge and connect to the solution concentration tank. The second solution pump is connected to the solution concentration tank and the second heat exchanger via a return pipe. The condensate pump is connected to the condensate tank and the first heat exchanger via a condensate pipe. The solution concentration tank is connected to the condensate tank via a steam pipe.

[0037] The solution concentration tank is equipped with a condenser heater. The solution concentration tank also includes a first pressure relief valve, a first pressure gauge, a first level gauge, a first thermometer, and a first drain pipe.

[0038] The condensate tank is equipped with an evaporative cooler. The condensate tank is also equipped with a second pressure relief valve, a second pressure gauge, a second thermometer, a second drain pipe, and a second level gauge.

[0039] An electric regulating valve is installed on the second dilute solution pipeline. Check valve one and check valve two are respectively installed at the outlets of the first and second solution pumps. Solution concentration monitoring devices are installed on the main antifreeze pipe to be treated and the return pipe to monitor the concentration of the antifreeze to be treated and the concentration of the treated solution. A gas flow meter is installed on the steam pipe.

[0040] The heat pump heating internal circulation system includes a compressor housing, a condenser heater, and an evaporator cooler. The compressor housing is connected to the condenser heater in the solution concentration tank via high-temperature, high-pressure refrigerant lines and a return line. The compressor housing is also connected to the evaporator cooler in the condensate tank via low-temperature, low-pressure refrigerant lines and a return line. The compressor housing contains a compressor and an expansion valve. The compressor controls the compression and pumping of the cooling medium to deliver heat, thereby heating the solution concentration tank and cooling the condensate tank. This process achieves the evaporation, condensation, and transfer of water in the antifreeze, resulting in the concentration of the antifreeze.

[0041] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0042] Example 1 like Figure 1 As shown, the solution concentration system based on parallel heat recovery consists of a solution concentration heat recovery system and a heat pump heating internal circulation system.

[0043] The solution concentration heat recovery system includes a first solution pump 22, a second solution pump 23, a condensate pump 24, a second heat exchanger 1, a first heat exchanger 2, a first water tank 3, and a second water tank 12. The first solution pump 22 is connected to the second heat exchanger 1 via a first inlet pipe 26 branching from the main antifreeze pipe 25. The first solution pump 22 is also connected to the first heat exchanger 2 via a second inlet pipe 29 branching from the main antifreeze pipe 25. The first inlet pipe 26 and the second inlet pipe 29 merge and connect to the first water tank 3. The second solution pump 23 is connected to the first water tank 3 and the second heat exchanger 1 via a return pipe 27. The condensate pump 24 is connected to the second water tank 12 and the first heat exchanger 2 via a condensate pipe 28. The first water tank 3 is connected to the second water tank 12 via a steam pipe 10. A condensate heater 4 is installed inside the first water tank 3.

[0044] The first water tank 3 is equipped with a first pressure relief valve 5, a first pressure gauge 6, a first level gauge 7, a first thermometer 8, and a first drain pipe 9. The second water tank 12 is equipped with an evaporative cooler 11. The second water tank 12 is equipped with a second pressure relief valve 13, a second pressure gauge 14, a second thermometer 15, a second drain pipe 16, and a second level gauge 17. A control valve 38, specifically an electric regulating valve, is installed on the second inlet pipe 29. A first check valve 35 and a second check valve 34 are respectively installed at the outlets of the first solution pump 22 and the second solution pump 23. A first concentration monitoring device 36 and a second concentration monitoring device 37 are respectively installed on the main antifreeze pipe 25 and the return pipe 27 to achieve online monitoring of the solution concentration. A gas flow meter 18 is installed on the steam pipe 10.

[0045] The heat pump heating internal circulation system includes a heat pump main unit 19, a condenser heater 4, and an evaporator cooler 11. The heat pump main unit 19 is located inside a compressor housing and contains a compressor 20. The compressor 20 is connected to the condenser heater 4 in the first water tank 3 via a high-temperature, high-pressure refrigerant pipeline 30 and a hot medium return pipeline 31. The compressor 20 is also connected to the evaporator cooler 11 in the second water tank 12 via a low-temperature, low-pressure refrigerant pipeline 33 and a cold medium return pipeline 32. An expansion valve 21 is also installed in the compressor housing. The expansion valve 21 is used to control the evaporation and condensation of the refrigerant circulation loop. Thus, the compressor 20, condenser heater 4, evaporator cooler 11, and expansion valve 21 are connected by pipelines [including the high-temperature, high-pressure refrigerant pipeline 30, the hot medium return pipeline 31, the cold medium return pipeline 32, and the low-temperature, low-pressure refrigerant pipeline 33] to form a heat pump system.

[0046] The solution concentration system based on parallel heat recovery of this invention employs two subsystems: a heat pump heating internal circulation system and a solution concentration heat recovery system. The heat pump heating internal circulation system heats and concentrates the antifreeze. Steam from the upper part of the first water tank is introduced into the condensate in the lower part of the second water tank via a steam pipe, achieving efficient steam condensation and separation. The steam from the first water tank directly enters the condensate for condensation and liquefaction. Compared to the evaporative cooler scheme where steam is blown onto the heat pump, the condensate has a higher efficiency for steam condensation, enabling efficient water vapor condensation and separation without a steam-driven fan.

[0047] Secondly, the condenser heater and evaporator cooler of the heat pump unit are located in the solutions of the first and second water tanks, respectively, allowing for more efficient heat exchange during heat pump operation. Then, when the concentrated antifreeze is returned to the first water tank via the return pipe, active heat exchange can be performed to recover heat and preheat the incoming antifreeze to be concentrated.

[0048] Simultaneously, considering the volume changes of the antifreeze to be concentrated and the concentrated antifreeze, a second inlet pipe and a condensate pipe are installed for heat exchange, realizing heat recovery before the condensate is discharged. Since the return pipe and the condensate pipe exchange heat with the antifreeze to be treated separately, they can be controlled independently. Due to the temperature difference between the discharged condensate and the returned antifreeze (caused by the temperature difference between the first and second water tanks after heating by the heat pump unit), different heat exchangers need to be controlled to achieve higher heat exchange efficiency.

[0049] Example 2 The method of using the solution concentration system based on parallel heat recovery in Example 1 above is as follows.

[0050] During the heating season, a solution heat recovery system and a heat pump heating internal circulation system are used to preheat and concentrate the solution. The solution heat recovery system exchanges heat between the high-temperature concentrated solution that meets the control concentration requirements and the medium-temperature condensate formed by water vapor condensation with the low-temperature dilute solution in parallel heat exchangers. This transfers heat from the concentrated solution and cooling condensate to the dilute antifreeze solution to be treated, thus completing the preheating of the dilute solution.

[0051] The heat pump heating internal circulation system condenses the water vapor discharged from the closed solution concentration tank into medium-temperature condensate in the condensate tank by the cooling coil. The heat pump absorbs the condensation heat of the water vapor in the condensate tank through the cooling coil, and then converts it into high-temperature heat energy at the cost of a small amount of electricity. This heat energy is then used to heat the solution through the heating coil, thus transferring heat from the condensate back to the solution.

[0052] Specifically, the operation mode of the solution concentration cycle is as follows: When the second concentration monitoring device 37 detects that the solution concentration in the first water tank [solution concentration tank] has reached the upper limit of the control concentration, it controls the second solution pump 23 to start, sending the concentrated solution (concentrated antifreeze) in the first water tank back to the heat exchange tower collection tank through the return pipe 27. When the first level gauge 7 at the bottom of the first water tank 3 detects that the solution level has reached the minimum allowable level, it controls the second solution pump 23 to stop. While the concentrated solution is being discharged from the first water tank, the first solution pump 22 and the condensate pump 24 are started to draw dilute solution [antifreeze to be concentrated] from the heat exchange tower and send it into the first water tank 3 through the first dilute inlet pipe 26 and the second inlet pipe 29. When the first level gauge 7 detects that the solution level has reached the maximum allowable level, it controls the first solution pump 22 to stop. To prevent backflow of solution when the first solution pump 22 and the second solution pump 23 stop operating, a first check valve 35 is installed on the antifreeze main pipe 25 to be treated, and a second check valve 34 is installed on the return pipe 27.

[0053] The specific operation mode of the condensate drainage system is as follows: When the second level gauge at the bottom of the condensate tank detects that the water level has reached the maximum allowable level, the condensate pump 24 is activated to discharge the condensate through the condensate pipe 28. When the second level gauge at the bottom of the second water tank (condensate tank) detects that the water level has reached the minimum allowable level, the condensate pump 24 is deactivated. When the condensate pump is activated to drain water, the control valve 38 on the second inlet pipe 29 is opened, and the first heat exchanger 2 is activated simultaneously.

[0054] The specific operating mode of the refrigerant cycle system is as follows: After absorbing heat in the evaporator 11 located at the bottom of the second water tank, the refrigerant returns to the compressor 20 located in the casing of the heat pump main unit 19 through the low-temperature, low-pressure refrigerant pipeline 33. The compressor 20, driven by electricity, compresses the low-temperature, low-pressure refrigerant into a high-temperature, high-pressure refrigerant, which is then sent to the condenser heater 4 located at the bottom of the first water tank through the high-temperature, high-pressure refrigerant pipeline 30. This heats the antifreeze solution in the first water tank, achieving solution concentration. After releasing heat, the high-temperature, high-pressure refrigerant is throttled by the expansion valve 21 on the high-temperature, high-pressure refrigerant pipeline 30, transforming into a low-temperature, low-pressure refrigerant. This refrigerant is then sent to the evaporator 11 located near the bottom of the second water tank through the low-temperature, low-pressure refrigerant pipeline 33, thereby cooling the water vapor transported by the steam pipe 10, or directly cooling the condensate in the second water tank to better absorb the steam transmitted from the steam pipe 10.

[0055] Effect analysis and demonstration: Currently, the mainstream method for maintaining solution concentration in the market generally adopts heating evaporation concentration technology, which directly provides heat through a heat pump unit to evaporate and remove excess water from the solution. However, survey data shows that this concentration method has an extremely high energy consumption, accounting for approximately 20% of the total energy consumption of the heat pump unit for winter heating. This high energy consumption directly increases the operating cost of the system, weakens the economic advantage of heat source tower heat pumps compared to traditional heating equipment, and has become a core bottleneck restricting its large-scale promotion and application in civil buildings, public facilities, and other fields. Especially for projects pursuing low-carbon operation and cost control, the burden brought by high energy consumption is undeniable. To address this challenge, Chinese utility model patent CN218392267U discloses a heat recovery technology for antifreeze concentration. However, this technology involves directly cooling the condensate by liquefying it into steam, and using a two-stage heat exchanger to recover heat from both the concentrate and the condensate. On one hand, steam cooling is limited by the contact area, and the heat absorption efficiency of the evaporative cooler is constrained by the overall transport conditions. On the other hand, during heat recovery, the antifreeze to be concentrated passes through two heat exchangers consecutively, resulting in a temperature gradient that is distributed across the two stages of heat exchange, reducing the temperature gradient and decreasing the heat recovery rate of the heat exchangers.

[0056] This invention proposes a heat recovery solution concentration device. Its core innovation lies in using parallel heat exchangers to recover heat from the concentrated solution and condensate, preheating the dilute solution and significantly reducing the actual energy consumption of the concentration process. In traditional heating evaporation concentration processes, the heating required for solution concentration relies entirely on a heat pump, consuming 2660J of heat per gram of solution concentrated. The new device, by recovering the waste heat from the concentrated solution and steam during heat pump operation, preheats the dilute solution, reducing the heating required for solution concentration to 2317J / g, a 13% reduction compared to conventional heating methods, and significantly reducing the heat output pressure of the heat pump. More importantly, this device significantly improves the operating energy efficiency of the concentration system. In traditional non-preheating heating evaporation concentration processes, due to the lack of a preheating stage, the heat pump needs to maintain a large circulating temperature difference to meet the evaporation requirements, resulting in an operating energy efficiency of only around 3.2 for the solution concentration unit. However, the heat recovery device, through preheating, effectively reduces the operating temperature difference of the heat pump, stabilizing the system condensate temperature at 70℃ and controlling the concentrated solution temperature at 105℃. Under these conditions, the operating energy efficiency of the device can be improved to over 5.0. This significant improvement in energy efficiency directly translates into a significant reduction in energy consumption. Calculations show that the heat pump energy consumption in the solution concentration stage can be reduced by approximately 48%, ultimately reducing the energy consumption of the entire solution concentration maintenance process from about 20% to 10% of the total energy consumption of the heat pump unit, achieving a 50% reduction in energy consumption.

[0057] From a practical application perspective, taking office buildings in hot-summer, cold-winter regions (such as cities in the Yangtze River basin like Shanghai, Nanjing, Wuhan, and Chengdu) as an example, these buildings have a clear winter heating need and are quite sensitive to operating costs. After adopting a heat recovery concentration device, approximately 1.1 kWh of energy can be saved per square meter of building area per year. If we calculate based on a medium-sized office building with a floor area of ​​10,000 square meters, the cumulative energy saving can reach 11,000 kWh per year. This not only reduces carbon emissions by approximately 6.6 tons (calculated based on the average carbon emission coefficient of 0.6 kg / kWh for thermal power), but also saves the building operator thousands of yuan in electricity costs, achieving both environmental and economic benefits. This overcomes a key bottleneck obstacle for the widespread application of heat source tower heat pump units.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0059] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0060] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0061] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0062] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0063] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

Claims

1. A solution concentration system based on parallel heat recovery, characterized in that, It consists of a heat pump heating internal circulation system and a solution concentration heat recovery system; The heat pump heating internal circulation system includes a first water tank (3), a second water tank (12), a heat pump host (19), and a steam pipe (10); The heat pump unit includes a compressor (20), a condenser heater (4), and an evaporator cooler (11). The condenser heater (4) is located near the bottom of the first water tank; the evaporator cooler (11) is located near the bottom of the second water tank. The compressor (20) is connected to the condenser heater (4) and the evaporator cooler (11) through pipelines to form a heat pump circulation loop; One end of the steam pipe (10) is connected to the top or top side of the first water tank (3), and the other end is connected to the bottom or bottom side of the second water tank (12). The solution concentration heat recovery system includes a first solution pump (22), a second solution pump (23), a condensate pump (24), a first heat exchanger (2), a second heat exchanger (1), a first inlet pipe (26), a second inlet pipe (29), a return pipe (27), and a condensate pipe (28). The inlet of the first solution pump (22) is connected to the antifreeze tank, and the outlet of the first solution pump (22) is connected to the antifreeze main pipe (25) to be treated. The antifreeze main pipe (25) to be treated is connected to the first inlet pipe (26) and the second inlet pipe (29) through a tee. A control valve (38) is provided on the second inlet pipe (29). The first inlet pipe (26) and the second inlet pipe (29) are both connected to the top or top side of the first water tank (3). One end of the return pipe (27) is connected to the bottom or side of the first water tank (3), and the other end of the return pipe (27) is used to connect to the antifreeze tank; The second solution pump (23) is installed on the return pipe (27); The second heat exchanger (1) is used to exchange heat between the first inlet pipe (26) and the return pipe (27); One end of the condensate pipe (28) is connected to the bottom or side of the second water tank (12), and the other end of the condensate pipe (28) is used to discharge condensate. The condensate pump (24) is installed on the condensate pipe (28); The first heat exchanger (2) is used to exchange heat between the second liquid inlet pipe (29) and the condensate pipe (28).

2. The solution concentration system based on parallel heat recovery according to claim 1, characterized in that, The first water tank is equipped with at least one of the following: a first pressure relief valve (5), a first pressure gauge (6), a first level gauge (7), a first thermometer (8), and a first drain pipe (9).

3. The solution concentration system based on parallel heat recovery according to claim 1, characterized in that, The second water tank is equipped with at least one of the following: a second pressure relief valve (13), a second pressure gauge (14), a second thermometer (15), a second drain pipe (16), and a second level gauge (17).

4. The solution concentration system based on parallel heat recovery according to claim 1, characterized in that, The control valve (38) is an electric regulating valve.

5. The solution concentration system based on parallel heat recovery according to claim 1, characterized in that, A first check valve (35) is installed on the main antifreeze pipe (25) to be treated.

6. The solution concentration system based on parallel heat recovery according to claim 1, characterized in that, A second check valve (34) is installed on the return pipe (27).

7. The solution concentration system based on parallel heat recovery according to claim 6, characterized in that, The second check valve (34) is located near the outlet of the second solution pump (23).

8. The solution concentration system based on parallel heat recovery according to claim 1, characterized in that, The antifreeze main pipe (25) to be treated is equipped with a first concentration monitoring device (36), and the return pipe (27) is equipped with a second concentration monitoring device (37).

9. The solution concentration system based on parallel heat recovery according to claim 1, characterized in that, A gas flow meter (18) is installed on the steam pipe.

10. A method of using the solution concentration system based on parallel heat recovery as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Use the first solution pump to deliver the antifreeze to be treated to the first water tank until the liquid level in the first water tank reaches the first preset height; S2. Start the heat pump heating internal circulation system to heat the solution in the first water tank, so that the water evaporates and enters the second water tank and is condensed into liquid; S3. When the solution concentration in the first water tank (3) reaches the first preset concentration, the second solution pump (23) is started to discharge back; at the same time, the first solution pump (22) is started to transport the antifreeze to be treated to the first water tank through the first inlet pipe (26), and the second heat exchanger (1) is started to recover heat. When the liquid level in the second water tank (12) reaches the second preset height, the condensate pump (24) is started to discharge the condensate in the second water tank; at the same time, the control valve (38) is opened, and the antifreeze to be treated is transported to the first water tank (3) through the second inlet pipe (29) by the first solution pump (22), and the first heat exchanger (2) is started to recover heat. S4. Repeat S1 or S3 so that the liquid level in the first water tank can submerge the condenser heater (4) and not exceed the first preset height; keep the heat pump heating internal circulation system working continuously in S2 until the concentration of all antifreeze to be treated is completed.

Images