A combined separated heat pipe evaporative condenser
By connecting a series combined separation of heat pipe heat exchangers in a traditional evaporative condenser and switching to a reinforced heat transfer tube, the problem of easy scale formation and small heat exchange area per unit volume is solved, achieving more efficient heat exchange and smaller equipment volume.
Patent Information
- Application Number
- CN202510180463.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2025-04-01
AI Technical Summary
Traditional evaporative condensers are prone to scale, their heat transfer coefficient is reduced, and their heat transfer area per unit volume is small, their weight is huge, and their metal consumption is large.
A combined separate heat pipe heat exchanger is connected in series between the precooler coil and the condenser coil of the traditional precooled evaporative condenser, and the condenser coil is replaced with a reinforced heat transfer tube, using heat pipe heat exchange technology and line-type heat exchange technology.
Through the heat pipe heat exchange technology, the temperature of the heat source fluid entering the condenser is reduced, the problem of scale formation of the condensation coil is avoided, the heat transfer area and efficiency under the same volume is increased, and the volume and metal consumption of the condensation coil are reduced.
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Figure CN119737704A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a condenser, in particular to a combined separated heat pipe evaporative condenser, belonging to the technical field of refrigeration accessory equipment. Background Art
[0002] The traditional evaporative condenser uses the spray water outside the condensing coil to absorb the heat of the high-temperature gaseous heat source fluid in the coil when it evaporates, so that the heat source fluid gradually condenses from gas to liquid; the cooling water is pumped to the spray device by the water pump and sprayed on the outer surface of the condensing coil to form a water film. A small part of the cooling water film absorbs the heat of the heat source fluid vapor in the tube and evaporates. At the same time, it contacts and exchanges heat with the fast-flowing air outside the tube, completing the heat exchange process mainly with latent heat and supplemented by sensible heat, and the heat is taken away by the air. Compared with other types of condensers, the traditional evaporative condenser has a higher heat transfer coefficient and higher heat exchange efficiency. It is a kind of equipment with high heat exchange efficiency, so it is widely used in many industrial fields. However, there are still some problems with the traditional evaporative condenser, the more prominent of which are: 1. The condensing coil is prone to scaling, which reduces the heat transfer coefficient. Since the traditional evaporative condenser uses circulating cooling water, the mineral content in the water is high. At the same time, since the temperature of the heat source fluid entering the condensing coil is relatively high, the minerals in the water are easily adsorbed on the surface of the condensing coil to form scale. The heat transfer coefficient will decrease after the condensing coil is scaled. In order to prevent scaling, the circulating water must be softened, but there is currently a lack of water softening treatment processes that are both economical, reliable and easy to operate. The scaling problem has, to a certain extent, restricted the widespread use of traditional evaporative condensers.
[0003] 2. The heat exchange area per unit volume of the traditional evaporative condenser is relatively small, the weight is large, and the metal consumption is large. In order to facilitate the treatment after scaling, the heat exchange coil of the traditional evaporative condenser is made of light tube. However, since the tube wall of the light tube is a smooth surface, the cooling water tends to be in a laminar state outside the tube, which greatly reduces the heat transfer coefficient of the condensing coil; in addition, the heat exchange area of the condensing coil made of this light tube is small under the same volume, and the heat exchange efficiency is poor. In order to achieve the purpose of condensation, the heat exchange area must be increased, which leads to the large volume and weight of the traditional evaporative condenser.
[0004] In order to solve the above problems, some people proposed a pre-cooling evaporative condenser, see attached Figure 1That is, a precooler is added to the traditional evaporative cooler, and the precooler coil is made of enhanced heat transfer tubes. Before the heat source fluid enters the condenser coil, it first enters the precooler coil for cooling, and then enters the condenser coil for condensation after the temperature is reduced to a temperature where water is not easy to scale (below 50ºC). However, since the precooler is an air cooler, the inlet air temperature is relatively high, and the temperature of the heat source fluid is difficult to drop below 50ºC, the problem of easy scaling of the condenser coil has not been completely solved. In order to make it easier to deal with the scaling of the condenser coil, it is necessary to still use a light tube to make the condenser coil. Therefore, the precooling type evaporative condenser has not been widely promoted and used.
[0005] Working principle of precooling evaporative condenser: The gaseous heat source fluid enters the precooler coil (b) from the heat source fluid air inlet (a) of the precooler coil, exchanges heat with the air outside the precooler coil, and is discharged from the heat source fluid air outlet (c) of the precooler coil after the temperature drops to a temperature close to the temperature at which water is not easily scaled, and enters the condenser coil (d), exchanges heat with the water and air outside the coil, and is discharged from the condenser coil (d) from the heat source fluid liquid outlet (e) of the condenser coil after condensation and heat release; the water pump (f) pumps the cooling water in the water tank (g) to the sprayer (h), and the sprayer (h) sprays the cooling water onto the condenser coil (d), and a small part of the water absorbs the heat released by the heat source fluid in the condenser coil (d), and the evaporated phase changes into water vapor and is sucked away by the fan (i), and the unevaporated water flows back to the water tank (g); the water vapor sucked away by the fan (i) and the water droplets carried in the air are intercepted by the water arrester (j) and returned to the water tank (g). Summary of the invention
[0006] In order to overcome the shortcomings of traditional evaporative condensers, the present invention provides a combined separated heat pipe evaporative condenser with a larger heat exchange area, higher heat exchange efficiency and no scaling under the same volume. The invention objective of the present invention is achieved through the following technical solutions: A combined heat pipe heat exchanger is connected in series between the precooler coil and the condenser coil of the traditional precooling evaporative condenser, and the condenser coil is made of enhanced heat transfer tubes, while other structures remain unchanged. This produces a new type of evaporative condenser - combined heat pipe evaporative condenser, the structure of which is shown in the attached Figure 2 and attached Figure 3 .
[0007] The traditional evaporative condenser is technically transformed by using heat pipe heat exchange technology and shell-and-tube heat exchanger technology. The specific technical solution is: a combined separated heat pipe heat exchanger is connected in series between the precooler coil and the condenser coil of the traditional precooling evaporative condenser, and the condensing coil in the traditional evaporative condenser is changed from a light tube to an enhanced heat exchange tube, and the other structures remain unchanged; the combined separated heat pipe heat exchanger is assembled in series by two horizontal shell-and-tube heat exchangers, one as the evaporation section of the heat pipe heat exchanger, and the other as the condensation section of the heat pipe heat exchanger. The basic working principle of the separated heat pipe heat exchanger is: after the heat pipe is evacuated, a certain amount of heat pipe working medium is filled in. The working medium liquid of the heat pipe in the evaporation section boils and evaporates to become saturated gas after being heated. The saturated gas carries heat and rises to the condensation section of the heat pipe along the riser under the action of a small pressure difference; in the condensation section of the heat pipe, the saturated gas releases heat and condenses into liquid, and returns to the evaporation section of the heat pipe along the downcomer under the action of gravity, forming a closed cycle, and the heat is continuously transferred from the evaporation section to the condensation section. The heat is transferred from the evaporation section to the condensation section through the transformation of the vapor and liquid phases of the working medium of the heat pipe. Since the heat is transferred by saturated steam, the temperature difference between the evaporation section and the condensation section is very small, which means that the heat pipe can transfer a large amount of heat with a small temperature difference. Due to this feature, the working medium gas temperature of the heat pipe entering the condensation section is relatively low, generally not exceeding the scaling temperature of water, and there is no need to worry about the scaling problem of the cooling water circulating outside the tube, so that the heat exchanger always maintains a high heat transfer coefficient. Therefore, the heat exchange coil of the traditional evaporative condenser can be changed from a light tube to an enhanced heat exchange tube. Compared with bare tubes, enhanced heat exchange tubes of the same volume greatly increase the heat transfer area and enhance the heat transfer efficiency. The absorption and release of latent heat of phase change is a highly efficient heat transfer process. Therefore, under the condition of the same heat exchange capacity, the volume of the condensing coil can be significantly reduced and the metal consumption can be reduced.
[0008] The shell side of the evaporation section carries heat source fluid, the tube side carries heat pipe working medium fluid, the shell side of the condensation section carries heat pipe working medium fluid, and the tube side carries heat sink fluid; the shell side air inlet of the evaporation section is connected to the air outlet of the precooler coil, and the shell side air outlet of the evaporation section is connected to the air inlet of the condenser; the tube side air outlet of the evaporation section is connected to the shell side air inlet of the condensing section, and the tube side liquid inlet of the evaporation section is connected to the shell side liquid outlet of the condensing section; the cooling water inlet of the condensing section is connected to the water outlet of the water pump, and the cooling water outlet is connected to the water tank.
[0009] In the evaporation section of the tube, the working medium of the heat pipe evaporates and absorbs heat, which is latent heat exchange with a high heat transfer coefficient. Outside the tube, the heat source fluid is cooled by gas, which is sensible heat exchange with a low heat transfer coefficient. Therefore, enhanced heat transfer measures are taken outside the tube-side heat exchange tube; outside the condensation section of the tube, the working medium of the heat pipe condenses and releases heat, which is latent heat exchange with a high heat transfer coefficient. Inside the tube, cooling water absorbs heat and cools, which is sensible heat exchange with a relatively low heat transfer coefficient. Therefore, forced heat exchange measures are adopted inside the tube for the heat exchange tube, and it can also be made of bare tubes.
[0010] The working principle of this combined separated heat pipe evaporative condenser is: The high-temperature superheated gas of the heat source fluid enters the precooler (16) from the precooler air inlet (17) of the precooler (16) and exchanges heat with the air outside the precooler (16) tube. After releasing heat and cooling down, the heat source fluid is discharged from the precooler air outlet (9) of the precooler (16), and then enters the shell side of the shell-and-tube heat exchanger (heat pipe evaporation section) (2) from the shell side air inlet (8) of the shell-and-tube heat exchanger (heat pipe evaporation section) (2), and exchanges heat with the heat pipe working medium in the tube side. After the temperature drops below 50°C, it is discharged from the shell side air outlet (10) of the shell-and-tube heat exchanger (heat pipe evaporation section) (2) and enters the condenser (18) from the condenser air inlet (11). In the condenser (18), the heat source fluid exchanges heat with the cooling water and air outside the tube, becomes a liquid at the saturation temperature, and is discharged from the condenser coil (18) from the condenser liquid outlet (19), completing the condensation process. In the tube side of the shell-and-tube heat exchanger (heat pipe evaporation section) (2), the liquid heat pipe working medium exchanges heat with the heat source fluid outside the tube, boils and evaporates into gas, and is discharged from the gas outlet (4) of the shell-and-tube heat exchanger (heat pipe evaporation section) (2), and enters the shell side of the shell-and-tube heat exchanger (heat pipe evaporation section) (3) from the shell side gas inlet (5) of the shell side of the shell-and-tube heat exchanger (heat pipe condensation section) (3). In the shell side of the shell-and-tube heat exchanger (heat pipe condensation section) (3), the gas heat pipe working medium exchanges heat with the heat sink fluid in the tube side, releases latent heat and changes into liquid, and is discharged from the shell side liquid outlet (6) of the shell-and-tube heat exchanger (heat pipe condensation section) (3) and returns to the tube side of the shell-and-tube heat exchanger (heat pipe evaporation section) (2) from the tube side liquid inlet (7) of the shell-and-tube heat exchanger (heat pipe evaporation section) (2), completing a cycle.
[0011] The water pump (13) draws cooling water from the water tank (15) and sends it to the sprayer (20). The sprayer (20) sprays the water onto the coil of the condenser (18). A small portion of the water absorbs the heat released by the heat source fluid and changes into water vapor, which is then drawn away by the fan (21). The air mixed with the water vapor flows through the precooler (16) and exchanges heat with the heat source fluid in the precooler tube before being discharged from the condenser. Most of the water that has not evaporated flows back to the water tank, and the water vapor and water droplets entrained in the air are intercepted by the water catcher (22) and then returned to the water tank.
[0012] The cooling water inlet (12) of the shell-and-tube heat exchanger (heat pipe condensation section) (3) is connected to the water outlet pipe of the water pump (13). The cooling water enters the tube side of the shell-and-tube heat exchanger (heat pipe condensation section) (3) through the cooling water inlet (12) of the shell-and-tube heat exchanger (heat pipe condensation section) (3), exchanges heat with the heat pipe working medium outside the tube side, and then returns to the water tank (15) from the cooling water outlet (14) of the shell-and-tube heat exchanger (heat pipe condensation section) (3).
[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Due to the use of heat pipe heat exchange technology, the temperature of the heat source fluid entering the condenser is greatly reduced, solving the problem of cooling water scaling caused by high heat exchange temperature; 2. Due to the reason 1 above, the condenser heat exchange coil can be made of enhanced heat exchange tubes, which greatly increases the heat transfer area and enhances the heat transfer efficiency under the same volume. Therefore, under the condition of the same heat exchange capacity, the volume of the heat exchange coil can be significantly reduced, the metal consumption can be reduced, and the product production cost and product operation cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Attached Figure 1 It is a pre-cooling evaporative condenser structure diagram Figure 1 Among them: (a) precooler inlet, (b) condensing coil, (c) precooler outlet, (d) condenser, (e) condenser liquid outlet, (f) water pump, (g) water tank, (h) sprinkler, (i) fan, and (j) water trap.
[0015] Attached Figure 2 This is the main view of the structure of the combined separated heat pipe evaporative condenser Attached Figure 3 This is a side view of the structure of a combined separated heat pipe evaporative condenser. Figure 2 , 3 Among them, (1) precooling type evaporative condenser, (2) shell and tube heat exchanger, (3) shell and tube heat exchanger, (4) shell and tube heat exchanger (2) tube side air outlet, (5) shell and tube heat exchanger (3) shell side air inlet, (6) shell and tube heat exchanger (3) shell side liquid outlet, (7) shell and tube heat exchanger (2) tube side liquid inlet, (8) shell and tube heat exchanger (2) shell side air inlet, (9) precooler air outlet, (10) shell and tube heat exchanger (2 ) Shell side air outlet, (11) Condenser air inlet, (12) Shell and tube heat exchanger (3) Cooling water inlet, (13) Water pump, (14) Shell and tube heat exchanger (3) Cooling water outlet, (15) Water tank, (16) Precooler, (17) Precooler air inlet, (18) Condenser, (19) Condenser liquid outlet, (20) Sprayer, (21) Fan, (22) Water collector, (23) Combined split heat pipe heat exchanger.
[0016] The following is combined with Figure 2 , Attachment Figure 3 Explain the structure of the combined separated heat pipe evaporative condenser: The structure of the combined split heat pipe evaporative condenser is the same as that of a conventional precooling type evaporative condenser. The fan (21) of the combined split heat pipe evaporative condenser is arranged at the top of the condenser. A precooler (16), a water trap (22), a sprayer (20), a condenser (18), and a water tank (15) are arranged in sequence downward from the fan (21). A combined split heat pipe heat exchanger (23) is connected in series between the air outlet (9) of the precooler (16) and the air inlet (11) of the condenser (18). A water pump (13) is arranged next to the water tank (15). The water inlet of the water pump (13) is connected to the water tank (15), and the water outlet is connected to the sprayer (20). The combined split heat pipe heat exchanger (23) is composed of two typical shell-and-tube heat exchangers: the shell-and-tube heat exchanger (2) serves as the heat pipe evaporation section, and the shell-and-tube heat exchanger (3) serves as the heat pipe condensation section. The shell-side air inlet (8) of the shell-and-tube heat exchanger (2) is connected to the precooler air outlet (9) of the precooler (16), and the shell-side air outlet (10) of the shell-and-tube heat exchanger (2) is connected to the air inlet (11) of the condenser (18); the tube-side air outlet (4) of the shell-and-tube heat exchanger (2) is connected to the shell-side air inlet (5) of the shell-and-tube heat exchanger (3), and the shell-side liquid outlet (6) of the shell-and-tube heat exchanger (3) is connected to the tube-side liquid inlet (7) of the shell-and-tube heat exchanger (3); the cooling water inlet (12) of the shell-and-tube heat exchanger (3) is connected to the water outlet pipe of the water pump (13), and the cooling water outlet (14) of the shell-and-tube heat exchanger (3) is connected to the water tank (15). DETAILED DESCRIPTION
[0017] The following is combined with Figure 2 , Attachment Figure 3 The present invention is described by way of example: This embodiment takes the combined separated heat pipe evaporative condenser used in the ammonia refrigeration system as an example to describe the working process, and its design working conditions are: Calculated outdoor dry bulb temperature for summer ventilation: 34ºC; The average outdoor wet-bulb temperature in summer is not guaranteed for 50 hours per year: 27ºC; Calculated relative humidity for outdoor ventilation in summer: 64%; Refrigeration system condensing temperature: 35°C; Refrigeration system refrigerant (heat source fluid): ammonia; Heat pipe working medium: ammonia.
[0018] The high-temperature superheated ammonia gas from the refrigeration system enters the precooler (16) from the precooler air inlet (17) of the precooler (16), exchanges heat with the air outside the precooler (16) tube, releases heat and lowers its temperature. When the temperature drops to 60°C, the refrigerant ammonia vapor is discharged from the precooler air outlet (9) of the precooler (16), and then enters the shell side of the shell-and-tube heat exchanger (2) from the shell side air inlet (8) of the shell-and-tube heat exchanger (2), exchanges heat with the heat pipe working medium liquid ammonia in the tube side, and lowers its temperature to below 50°C. It is then discharged from the shell side air outlet (10) of the shell-and-tube heat exchanger (2) and enters the condenser (18) from the condenser air inlet (11). In the condenser (18), the refrigerant ammonia vapor exchanges heat with the cooling water and air outside the tube, and becomes a saturated liquid at the condensation temperature. It is discharged from the condenser liquid outlet (19) of the condenser (18), completing the condensation process, and then enters the refrigeration system.
[0019] The heat pipe working medium liquid ammonia in the tube side of the shell-and-tube heat exchanger (2) exchanges heat with the refrigerant hot ammonia vapor outside the tube, boils and evaporates into gas, and is discharged from the tube side gas outlet (4) of the shell-and-tube heat exchanger (2), and enters the shell side of the shell-and-tube heat exchanger (3) from the shell side gas inlet (5). In the shell side of the shell-and-tube heat exchanger (3), the heat pipe working medium ammonia vapor exchanges heat with the cooling water in the tube side, releases latent heat and changes into a 40°C liquid, and is discharged from the shell side liquid outlet (6) of the shell-and-tube heat exchanger (3) and returns to the tube side of the shell-and-tube heat exchanger (2) from the tube side liquid inlet (7), completing a cycle.
[0020] The cooling water inlet (12) of the shell-and-tube heat exchanger (3) is connected to the outlet pipe of the water pump (13), and the cooling water enters the tube side of the shell-and-tube heat exchanger (3) through the cooling water inlet (12) of the shell-and-tube heat exchanger (3), exchanges heat with the ammonia gas, a working medium of the heat pipe outside the tube side, and then returns to the water tank (15) from the cooling water outlet (14) of the shell-and-tube heat exchanger (3).
[0021] The water pump (13) draws cooling water from the water tank (15) and sends it to the sprayer (20). The sprayer (20) sprays the water onto the coil of the condenser (18). A small portion of the water absorbs the heat released by the heat source fluid and changes into water vapor, which is then drawn away by the fan (21). The air mixed with the water vapor flows through the precooler (16) and exchanges heat with the refrigerant ammonia vapor in the precooler tube before being discharged from the condenser. Most of the water that has not evaporated flows back to the water tank, and the water vapor and water droplets carried in the air are intercepted by the water catcher (22) and then returned to the water tank.
[0022] The present invention is not limited to the above embodiments. Based on the technical solution disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features according to the disclosed technical content without creative labor, and these substitutions and modifications are within the protection scope of the present invention.
Claims
1. A combined separated heat pipe evaporative condenser, mainly comprising a precooling evaporative condenser (1), a shell-and-tube heat exchanger (2), and a shell-and-tube heat exchanger (3), characterized in that: The tube-side air outlet (4) of the shell-and-tube heat exchanger (2) is connected to the shell-side air inlet (5) of the shell-and-tube heat exchanger (3); the shell-side liquid outlet (6) of the shell-and-tube heat exchanger (3) is connected to the tube-side liquid inlet (7) of the shell-and-tube heat exchanger (2); the shell-side air inlet (8) of the shell-and-tube heat exchanger (2) is connected to the precooler air outlet (9); the shell-side air outlet (10) of the shell-and-tube heat exchanger (2) is connected to the condenser air inlet (11); the cooling water inlet (12) of the shell-and-tube heat exchanger (3) is connected to the outlet pipe of the water pump (13); and the cooling water outlet (14) of the shell-and-tube heat exchanger (3) is connected to the water tank (15).