Heat pipe type evaporative condenser
By using heat pipe heat exchanger technology in the evaporative condenser, the two-phase heat transfer of the heat pipe working medium is solved, and the large scale and volume problems of the evaporative condenser are improved, and the heat transfer efficiency is reduced and power consumption is reduced.
Patent Information
- Application Number
- CN202411648883.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-01-10
AI Technical Summary
Existing evaporative condensers are prone to scale, have a reduced heat transfer coefficient, have a small heat exchange area per unit volume, are huge in weight, and have high metal consumption.
Using heat pipe heat exchanger technology, the condensation coil is converted into a reinforced heat exchanger, and the separated gravity heat pipe heat exchanger is added. The two-phase heat transfer of the heat pipe working medium is used to reduce the scaling risk of cooling water circulating outside the pipe, and pass through waste gas Cooling significantly reduces power consumption.
It improves the heat transfer efficiency of the condenser, reduces volume and metal consumption, avoids scale problems, and significantly reduces power consumption and production costs.
Smart Images
Figure CN119289558A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a condenser, in particular to a heat pipe type evaporative condenser. Background Art
[0002] The existing evaporative condenser utilizes the spray water outside the condensing coil to absorb the heat of the high-temperature gaseous condensed medium in the coil when it evaporates, so that the condensed medium in the tube 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, and part of the cooling water film absorbs the heat of the refrigerant vapor in the tube and then evaporates, and 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.
[0003] Attached Figure 1 This is the existing evaporative condenser structure diagram In the figure, (a) condensing coil, (b) air inlet of condensed medium, (c) liquid outlet of condensed medium, (d) water pump, (e) water tank, (f) water collector, (g) sprinkler, and (h) fan.
[0004] The working principle of the existing evaporative condenser is as follows: the gaseous condensed medium enters the condensing coil (a) from the condensed medium air inlet (b) and condenses and releases heat, and then changes phase into liquid and is discharged from the condensing coil (a) from the condensed medium liquid outlet (c); the water pump (d) pumps the cooling water in the water tank (e) to the sprayer (f), and the sprayer (f) sprays the cooling water onto the condensing coil (a), and a part of the water absorbs the heat released by the condensed medium in the condensing coil (a), and then evaporates and changes phase into water vapor and is sucked away by the fan (h), and the unevaporated water flows back to the water tank (e); the water vapor sucked away by the fan (h) and the water droplets carried in the air are intercepted by the water collector (g) and returned to the water tank (e).
[0005] Compared with other types of condensers, the existing evaporative condenser has a higher heat transfer coefficient and heat exchange efficiency. It is a high-efficiency heat exchange equipment with relatively low total power consumption and high energy efficiency. Therefore, it is widely used in many industrial fields. However, the existing evaporative condenser still has some problems, the most prominent of which are: 1. The condensing coil is prone to scaling, resulting in a decrease in the heat transfer coefficient. Since the existing evaporative condenser uses circulating cooling water, the mineral content in the water is relatively high. At the same time, since the temperature of the condensed medium 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. According to test data, when the scaling thickness is 0.5mm, the condensing pressure will increase by 0.15MPa and the power consumption will increase by 19%; when the scaling thickness is 1mm, the condensing pressure will increase by 0.22MPa and the power consumption will increase by 39%. 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 existing evaporative condensers.
[0006] 2. The existing evaporative condenser has a relatively small heat exchange area per unit volume, is heavy, and consumes a lot of metal. In order to facilitate handling after scaling, the heat exchange coils of the existing evaporative condensers are mostly made of smooth tubes. However, since the tube wall of the smooth tube is a smooth surface, the cooling water is likely to be in a laminar state outside the tube and produce a boundary layer. The appearance of the boundary layer greatly reduces the heat transfer coefficient of the condensing coil; in addition, the heat exchange area of the condensing coil with a smooth surface of the same volume is small 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 existing evaporative condenser. Summary of the invention
[0007] In order to overcome the shortcomings of existing evaporative condensers, the present invention provides a heat pipe evaporative condenser with a larger heat exchange area, higher heat exchange efficiency and less prone to scaling under the same volume. The invention objective of the present invention is achieved by adopting the following technical solutions: The existing evaporative condenser is technically transformed by using heat pipe heat exchanger technology and shell-and-tube heat exchanger technology, resulting in a new type of evaporative condenser - heat pipe evaporative condenser. The specific technical solution is: the condensing coil in the existing evaporative condenser is changed from a light tube to an enhanced heat exchange tube as the condensing coil of the heat pipe evaporative condenser; the tube coil of the shell-and-tube heat exchanger is changed from a light tube to an enhanced heat exchange tube as the evaporation section of the heat pipe heat exchanger; a group of heat exchanger coils made of enhanced heat exchange tubes is added as the condensation section of the heat pipe heat exchanger. The air outlet of the heat pipe evaporation section is connected to the air inlet of the condensation section, and the liquid outlet of the heat pipe condensation section is connected to the liquid inlet of the heat pipe evaporation section, thus forming a separated gravity heat pipe heat exchanger. The basic working principle of the separated gravity heat pipe heat exchanger is: after the heat pipe is evacuated, a certain amount of heat pipe working medium is filled in. After the heat pipe working medium liquid in the evaporation section is heated, it boils and evaporates to become saturated gas. The saturated gas carries heat and rises to the heat pipe condensation section along the riser under the action of a small pressure difference; in the heat pipe condensation section, the saturated gas releases heat and condenses into liquid, and returns to the heat pipe evaporation section along the downcomer under the action of gravity, forming a closed cycle, and heat is continuously transferred from the heat pipe evaporation section to the heat pipe condensation section. The heat is transferred from the heat pipe evaporation section to the heat pipe condensation section through the transformation of the steam and liquid phases of the heat pipe working medium. Since the heat is transferred by saturated steam, the temperature difference between the heat pipe evaporation section and the heat pipe condensation section is very small, which means that the heat pipe can transfer a large amount of heat under a small temperature difference. Due to this feature, the temperature of the working medium gas entering the heat pipe condensation section is relatively low, generally not exceeding the scaling temperature of water, so there is no need to worry about the scaling 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 existing evaporative condenser can be changed from a bare tube to an enhanced heat exchange tube. Compared with a bare tube, the enhanced heat exchange tube of the same volume greatly increases the heat transfer area and enhances the heat transfer efficiency. The absorption and release of the 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 working medium of the heat pipe in the evaporation section of the heat pipe and the condensed medium in the shell of the shell-and-tube heat exchanger are both organic substances, so there is no scaling problem. The heat exchange coil of the evaporation section of the heat pipe is made of enhanced heat exchange tubes; the condensation section of the heat pipe heat exchanger uses the air that is about to be discharged from the heat exchanger as the cooling medium, and there is no structural problem, so the condensation section of the heat pipe heat exchanger is also made of enhanced heat exchange tubes. The condensation section of the heat pipe heat exchanger fully utilizes the coldness in the exhaust gas discharged by the fan to reduce the power consumption of the entire condenser.
[0009] The working principle of this heat pipe evaporative condenser is as follows: the high-temperature superheated gas of the condensed medium enters the shell side of the shell and tube heat exchanger from the air inlet of the shell and tube heat exchanger, exchanges heat with the heat pipe working medium in the evaporation section of the heat pipe heat exchanger, becomes saturated temperature gas and is discharged from the air outlet of the shell and tube heat exchanger, and enters the condenser coil along the condensed medium riser. In the condenser coil, the saturated temperature gas exchanges heat with the cooling water and air outside the tube, condenses into liquid and is discharged from the condensed medium liquid outlet of the condenser; the heat pipe working medium absorbs the heat released by the condensed medium in the heat pipe evaporation section and changes into saturated gas, then is discharged from the heat pipe working medium air outlet, and enters the heat pipe condensation section along the heat pipe working medium riser. In the heat pipe condensation section, the heat pipe working medium releases heat and changes into liquid, is discharged from the heat pipe working medium liquid outlet, and returns to the heat pipe evaporation section along the heat pipe working medium descending tube, forming a closed cycle.
[0010] The water pump draws cooling water from the water tank and sends it to the sprinkler. The sprinkler sprays the water to the condensing section of the heat pipe. A small part of the water absorbs the heat released by the working medium of the heat pipe and changes into water vapor, which is then drawn away by the fan. The air mixed with water vapor flows through the condensing section of the heat pipe and is discharged from the device. Most of the unevaporated water flows back to the water tank, and the water droplets carried in the air are intercepted by the water collector and returned to the water tank.
[0011] 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 heat exchange temperature of the condenser is greatly reduced, overcoming the problem of cooling water scaling caused by high heat exchange temperature.
[0012] 2. The condenser coil, the coil of the heat pipe condensing section, and the coil of the heat pipe evaporating section are all 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.
[0013] 3. Since the air that is about to be discharged as exhaust gas is fully utilized as the cooling medium of the heat pipe condensation section, compared with the existing evaporative condenser, the power consumption of the heat pipe evaporative condenser is significantly reduced and the energy efficiency ratio is greatly increased. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Attached Figure 1 This is the existing evaporative condenser structure diagram Attached Figure 2 This is the structural diagram of the heat pipe evaporative condenser In the figure, (1) shell and tube heat exchanger, (2) heat pipe evaporation section, (3) shell of shell and tube heat exchanger, (4) heat pipe working medium air outlet, (5) heat pipe condensation section, (6) heat pipe working medium air inlet, (7) heat pipe working medium riser, (8) heat pipe working medium liquid inlet, (9) heat pipe working medium downcomer, (10) heat pipe working medium liquid outlet, (11) water pump, (12) water tank, (13) sprayer, (14) water collector, (15) condenser, (16) fan, (17) shell and tube heat exchanger air inlet, (18) shell and tube heat exchanger air outlet, (19) condensed medium riser, (20) condensed medium air inlet, and (21) condensed medium liquid outlet.
[0015] Structural description of heat pipe evaporative condenser: The fan (16) is arranged at the top of the heat pipe evaporative condenser. The heat pipe condensation section (5), the water collector (14), the sprayer (13), the condenser (15), the water tank (12), and the shell-and-tube heat exchanger (1) are arranged in order from top to bottom below the fan (16). The water pump (11) is arranged beside the water tank (12), and its inlet is connected to the water tank (12), and its outlet is connected to the sprayer (13).
[0016] The tube side of the shell-and-tube heat exchanger (1) is placed in a shell-and-tube heat exchanger shell (3) as a heat pipe evaporation section (2). The heat pipe working medium gas outlet (4) of the heat pipe evaporation section (2) is connected from the upper part of one end of the shell-and-tube heat exchanger shell (3) and is connected to the heat pipe working medium gas inlet (6) of the heat pipe condensation section (5) through an ascending pipe (7). The heat pipe working medium liquid inlet (8) of the heat pipe evaporation section (2) is connected from the middle part of a head at one end of the shell-and-tube heat exchanger shell (3) and is connected to the heat pipe working medium liquid outlet (10) of the heat pipe condensation section (5) through a heat pipe working medium descending pipe (9).
[0017] A condensed medium air inlet (17) is provided at the upper portion of one end of the shell and tube heat exchanger (3), and a condensed medium air outlet (18) is provided at the upper portion of the other end and is connected to a condensed medium air inlet (20) at the upper portion of a section of the condenser (15) via a condensed medium riser (19). A condensed medium liquid outlet (21) is provided at the lower portion of the other end of the condenser (15). DETAILED DESCRIPTION
[0018] The following is combined with Figure 2 The present invention is described by way of example: This embodiment takes the 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 working medium (condensed medium): ammonia; Heat pipe working medium: ammonia.
[0019] The heat exchange coils of the condenser (15) and the heat pipe condensation section (5) are both made into high-fin enhanced heat exchange tubes, and the coils of the heat pipe evaporation section (2) are made into low-fin enhanced heat exchange tubes. The superheated ammonia gas, which is a condensed medium with a temperature of about 150°C, from the refrigeration system enters the shell side of the shell-and-tube heat exchanger (1) through the condensed medium air inlet (17) of the shell-and-tube heat exchanger (1), exchanges heat with the saturated heat pipe working medium ammonia liquid in the tube of the heat pipe heat exchanger evaporation section (2), and the superheated ammonia gas continuously releases heat to become a superheated gas at about 50°C, and then is discharged from the condensed medium air outlet (18) of the shell-and-tube heat exchanger (1), and enters the condenser (15) from the condensed medium air inlet (20) of the condenser along the condensed medium riser (19). In the condenser (15), the superheated ammonia gas, which is a condensed medium, at about 50°C exchanges heat with the cooling water and air outside the tube, and condenses into a saturated ammonia liquid at 35°C, and then enters the refrigeration system from the condensed medium liquid outlet (21) of the condenser (15).
[0020] The saturated ammonia liquid as the working medium of the heat pipe absorbs the heat released by the superheated ammonia gas of the condensing medium in the coil of the heat pipe evaporation section (2) and changes into ammonia superheated gas at about 45°C. The liquid is then discharged from the heat pipe working medium outlet (4) and rises along the heat pipe working medium riser (7). The liquid enters the heat pipe condensation section (5) from the heat pipe working medium inlet (6) of the heat pipe condensation section. The saturated ammonia gas in the heat pipe condensation section (5) releases heat and changes into ammonia saturated liquid at about 40°C. The liquid returns along the heat pipe working medium downcomer (9) and enters the heat pipe evaporation section (2) from the heat pipe working medium inlet, forming a closed cycle. Heat is continuously transported from the heat pipe evaporation section (2) to the heat pipe condensation section (5).
[0021] The water pump (11) draws cooling water from the water tank (12) and sends it to the sprayer (13). The sprayer (13) sprays the water onto the heat pipe condensation section (15) to form a water film. A small portion of the water absorbs the heat released by the ammonia gas in the heat pipe condensation section (15) and then changes into water vapor and is drawn away by the fan (16). Most of the unevaporated water returns to the water tank (12). The water vapor drawn away by the fan (16) and the water droplets carried in the air are intercepted by the water collector (14) and then return to the water tank (12).
[0022] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.
Claims
1. A heat pipe evaporative condenser, mainly comprising: A shell and tube heat exchanger (1), a heat pipe condensing section (5), a water pump (11), a water tank (12), a sprayer (13), a water collector (14), a condenser (15), and a fan (16), characterized in that the fan (16) is arranged at the top of the heat pipe evaporative condenser, and the heat pipe condensing section (5), the water collector (14), the sprayer (13), the condenser (15), the water tank (12), and the shell and tube heat exchanger (1) are arranged in order from top to bottom below the fan (16); the tube side of the shell and tube heat exchanger (1) is placed in the shell and tube heat exchanger shell (3) as the heat pipe evaporating section (2); the heat pipe working medium outlet (4) of the heat pipe evaporating section (2) is connected to the upper part of one end of the shell and tube heat exchanger shell (3) The heat pipe is then connected to the heat pipe working medium air inlet (6) of the heat pipe condensation section (5) through the riser (7); the heat pipe working medium liquid inlet (8) of the heat pipe evaporation section (2) is connected to the heat pipe working medium liquid outlet (10) of the heat pipe condensation section (5) through the heat pipe working medium downcomer (9); a condensed medium air inlet (17) is provided at the upper part of one end of the shell of the shell and tube heat exchanger (3); a condensed medium air outlet (18) is provided at the upper part of the other end and is connected to the condensed medium air inlet (20) at the upper part of a section of the condenser (15) through the condensed medium riser (19); and a condensed medium liquid outlet (21) is provided at the lower part of the other end of the condenser (15).
2. The heat pipe evaporative condenser according to claim 1, characterized in that: The water pump (11) is arranged beside the water tank (12), the inlet of the water pump is connected to the water tank (12), and the outlet of the water pump is connected to the sprinkler (13).
3. The heat pipe evaporative condenser according to claim 1 and claim 2, characterized in that: The heat exchange coils of the heat pipe evaporation section (2), the heat pipe condensation section (5) and the condenser (15) are all made of enhanced heat exchange tubes.