Negative pressure evaporation heating system based on R718

Abstract

The utility model relates to the technical field of negative pressure evaporation heating, and discloses a negative pressure evaporation heating system based on R718, which comprises a heat exchanger, a vacuum pump and a water inlet valve, the heat exchanger is used for exchanging heat, cooling water absorbs heat to become water vapor, the vacuum pump is used for extracting the water vapor in an inner container of the heat exchanger, and the water inlet valve is connected with the water inlet valve. According to the negative pressure evaporation heating system based on the R718, on the basis of a traditional reverse Carnot cycle, a condenser of a traditional air energy system and a positive pressure flash evaporation heat exchange system designed for effectively separating steam are omitted, the open type reverse Carnot cycle is adopted, and the negative pressure evaporation heating system based on the R718 is simple in structure, convenient to operate and high in efficiency. And the concept of negative pressure flash evaporation is directly introduced. A condenser, a positive pressure flash evaporation heat exchange system, a capillary tube and other essential structures of a traditional closed type reverse Carnot cycle are omitted, meanwhile, a compressor is replaced with a vacuum pump, the pressure and cost of the system and the requirements for production design are reduced, and the occupied area is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of negative pressure evaporation heating, in particular to a negative pressure evaporation heating system based on R718. Background Art

[0002] In modern industrial production, many industries need to use high-temperature steam. The existing heating mechanisms include overlapping heat exchangers, high-temperature compressors, high-temperature condensers, expansion valves, flash tanks, circulating water pumps, flow control valves, make-up water pumps, and water vapor compressors. The existing technology is based on R245FA refrigerant, adopts a complete reverse Carnot cycle, and uses low-boiling point refrigerants and high-temperature refrigerants in a fully closed state. This results in the need to set up a separate condenser when the R245FA refrigerant is used for steam generation, and the condenser needs to be used together with the flash evaporator to produce steam, which makes the overall structure complex, resulting in low heating efficiency, and the overall structure is large and occupies a large area.

[0003] Compared with the traditional R245FA refrigerant, when producing steam, it needs to be isolated from water for heat conduction, which affects the working efficiency of the reverse Carnot cycle.

[0004] Secondly, the traditional reverse Carnot cycle uses R245FA high-temperature refrigerant, and its pipelines require greater pressure. The traditional R245FA refrigerant piping system is based on a fully closed reverse Carnot cycle design. Each square meter of pipe in the piping system needs to bear greater pressure, which puts forward certain requirements for the design, materials and welding of the piping system. Utility Model Content

[0005] In view of the shortcomings of the prior art, the utility model provides a negative pressure evaporation heating system based on R718, which has the advantages of reducing the pressure, cost and production design requirements of the system and reducing the floor space. The system effectively improves the efficiency of steam generation, increases safety, and reduces carbon dioxide emissions.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A negative pressure evaporative heating system based on R includes a heat exchanger, a vacuum pump, a water inlet valve and a piping system. The heat exchanger utilizes low-quality thermal energy and adopts a low-temperature boiling method of water so that the water absorbs the low-quality thermal energy and turns into steam. The vacuum pump is used to extract water vapor and maintain the pressure inside the heat exchanger. The water inlet valve is used to control the inlet and outlet of condensed water.

[0008] Preferably, the output end of the heat exchanger is connected to the input end of the vacuum pump through a pipeline.

[0009] Preferably, the heat exchanger is a high-efficiency tank heat exchanger, and a high-temperature pressure detector is provided inside the heat exchanger.

[0010] Preferably, the vacuum pump is a dry screw vacuum pump.

[0011] Preferably, the water inlet valve is a negative pressure water inlet solenoid valve.

[0012] Preferably, the output end of the water inlet valve is connected to the input end of the heat exchanger through a pipeline.

[0013] Preferably, the output end of the vacuum pump is connected to a one-way solenoid valve, the output end of the vacuum pump is connected to a safety valve, and the output end of the one-way solenoid valve is connected to the input end of the heat exchanger.

[0014] Preferably, the pipeline at the output end of the safety valve is connected to a semi-enclosed water tank, a steam pipeline is provided between the safety valve and the semi-enclosed water tank, and condensed water exists inside the semi-enclosed water tank.

[0015] Preferably, the pipe connection at the output end of the vacuum pump is arranged on the upper side of the water interface of the semi-enclosed water tank.

[0016] Preferably, the output end pipe of the semi-enclosed water tank is connected to the input end of the water inlet valve, and the output end pipe of the semi-enclosed water tank is arranged below the horizontal plane of the water inside the semi-enclosed water tank, and the pipe materials of the pipe system are all insulating materials.

[0017] Beneficial effects:

[0018] 1. The negative pressure evaporation heating system based on R718, on the basis of the traditional reverse Carnot cycle, cancels the condenser of the traditional air energy system and the positive pressure flash heat exchange system designed for effective steam separation. The utility model adopts an open reverse Carnot cycle and directly introduces the concept of negative pressure flash. The condenser, positive pressure flash heat exchange system, capillary tube and other indispensable structures of the traditional closed reverse Carnot cycle are cancelled, and the compressor is replaced by a vacuum pump, which reduces the system pressure, cost and production design requirements, and reduces the floor space.

[0019] 2. The negative pressure evaporation heating system based on R718 adopts an open reverse Carnot cycle. The steam generation is carried out directly in the system. There is no heat exchange with the back end. The separation, temperature and pressure of the steam can be provided directly by the vacuum pump. The refrigerant is no longer required to provide an additional temperature difference, and the flash tank and condenser are no longer required for heat exchange and separation. The temperature difference required to be created by the reverse Carnot cycle heat pump is reduced, and the circulating water pump required for the flash tank is completely eliminated, which reduces the number of heat conductions and effectively improves the efficiency of steam generation.

[0020] 3. The negative pressure evaporation heating system based on R718 uses water as the refrigerant, and changes the traditional closed reverse Carnot cycle high-pressure system into a 19Kpa negative pressure system, that is, a -81Kpa evaporation system under atmospheric pressure. It also reduces a large number of processes that require closed welding between the vacuum pump and the water inlet valve. Even if the pipeline ruptures, it will only cause a loss of pressure, which increases the safety of the entire system.

[0021] 4. The negative pressure evaporation heating system based on R718 adopts an open reverse Carnot cycle, creatively eliminating the high-temperature condenser, flash tank, circulating water pump, flow control valve and expansion valve, as well as the high-temperature steam compressor, and the intermediate supporting piping system, and electronic system, etc. At the same time, the required pipelines are changed from high-pressure resistant pipelines to ordinary normal-pressure corrosion-resistant pipelines. The elimination of these designs can reduce production costs.

[0022] 5. The negative pressure evaporative heating system based on R718 adopts an open reverse Carnot cycle. Water directly exchanges heat with the previous refrigeration system through the evaporator, eliminating the condenser and flash tank. The temperature and pressure of the steam are directly controlled by the vacuum pump, which greatly reduces the volume of the entire system and makes it possible to develop a 3-6-9-12KW micro air energy steam module for small steam equipment.

[0023] 6. This negative pressure evaporative heating system based on R718 uses an open reverse Carnot cycle and R718 as the first application of a high-temperature refrigerant, effectively filling the gap in the industry's previous lack of R718 as a high-temperature refrigerant. It can provide society with cleaner and cheaper steam, thereby greatly reducing the cost of steam plants in producing steam and reducing their carbon dioxide emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the overall circulation structure diagram of the utility model;

[0025] Figure 2 This is the principle diagram of the utility model;

[0026] Figure 3 This is a diagram showing the relationship between pressure and volume of the utility model;

[0027] Figure 4 This is the input and output diagram of the cycle of the utility model.

[0028] In the figure: 1. Heat exchanger; 2. Vacuum pump; 3. Water inlet valve; 4. Semi-enclosed water tank; 5. One-way solenoid valve; 6. Safety valve. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] Embodiment 1:

[0031] See also Figure 1-Figure 4 A negative pressure evaporation heating system based on R718 includes a heat exchanger 1, a vacuum pump 2, a water inlet valve 3 and a pipeline system. The heat exchanger 1 uses low-quality thermal energy and adopts a low-temperature boiling method of water to make the water absorb low-quality thermal energy and become steam. The vacuum pump 2 is used to extract water vapor and maintain the pressure inside the heat exchanger 1. The water inlet valve 3 is used to control the inlet and outlet of condensed water.

[0032] The output end of the heat exchanger 1 is connected to the input end of the vacuum pump 2 through a pipeline.

[0033] The heat exchanger 1 adopts a high-efficiency tank heat exchanger, and a high-temperature pressure detector is arranged inside the heat exchanger 1.

[0034] The vacuum pump 2 is a dry screw vacuum pump.

[0035] The water inlet valve 3 adopts a negative pressure water inlet solenoid valve.

[0036] The output end of the water inlet valve 3 is connected to the input end of the heat exchanger 1 through a pipeline.

[0037] The output end of the vacuum pump 2 is connected to a one-way solenoid valve 5 , the output end of the vacuum pump 2 is connected to a safety valve 6 , and the output end of the one-way solenoid valve 5 is connected to the input end of the heat exchanger 1 .

[0038] Working process: adjust the safety valve 6, keep the gas flowing in the safety valve 6 under atmospheric pressure, pass low-grade heat energy, that is, heat energy with a temperature of more than 60°C, into the heat exchanger 1, and heat exchange is carried out in the heat exchanger 1. The water in the heat exchanger 1 is heated to 60°C. The calculation formula of the saturated vapor pressure of water is:

[0039] Calculated using the Antony equation:

[0040] lgP=A-(B / (T+C))(10℃<T<168℃) In the formula: P—vapor pressure of the substance;

[0041] t—temperature, °C. A, B, C are constants for the vapor pressure of water at different temperatures;

[0042] After calculation, P=19.923Kpa.

[0043] The cooling water in the heat exchanger 1 is heated, and the vacuum pump 2 is started. Through mechanical movement, gas molecules are absorbed from the heat exchanger 1 and gradually discharged into the pipeline system. The exhaust rate of the vacuum pump 2 gradually increases, so that the gas inside the heat exchanger 1 is gradually reduced, thereby reducing the gas pressure inside the heat exchanger 1, making it impossible for the extracted gas to flow back, maintaining the negative pressure state in the heat exchanger 1, and detecting the pressure inside the heat exchanger 1 in real time through the high-temperature pressure detector.

[0044] When the high-temperature pressure detector detects that the internal pressure of the heat exchanger 1 is 81 Kpa lower than the atmospheric pressure, water is used as the refrigerant, and the high-pressure system of the traditional closed reverse Carnot cycle is changed to a negative pressure system 81 Kpa lower than the atmospheric pressure. A large number of processes requiring welding are reduced between the vacuum pump 2 and the water inlet valve 3. Even if the pipeline is broken, it will only cause a loss of pressure, thereby increasing the safety of the entire system.

[0045] At this time, the mechanical movement rate of the vacuum pump 2 is controlled so that the gas pressure inside the heat exchanger 1 stops decreasing. By utilizing the low-temperature boiling principle of water, when the temperature exceeds the boiling point of water at the gas pressure (at 19.923 Kpa, the boiling point of water is 60°C), the water absorbs heat and transforms from liquid phase to gas phase to generate water vapor.

[0046] The cooling water is heated to water vapor by heat conduction through heat exchanger 1. When the water vapor passes through vacuum pump 2, at 19.932Kpa, the water vapor enters normal pressure (atmospheric pressure) from a low pressure state. Due to the principle of conservation of energy and the different boiling points of water at different pressures, and the large heat of evaporation of water vapor, the enthalpy of water vapor is much greater than the enthalpy of water. In the end, part of the 60°C water vapor condenses into water due to insufficient energy, and the rest of the steam absorbs energy and is converted into a state that can exist stably at room temperature (i.e., the compression and self-absorption of water vapor, from 60°C to 100°C, and a part of it becomes liquid water).

[0047] The temperature of water vapor rises, and we get 100℃ water vapor under normal pressure and part of it turns back into water due to insufficient enthalpy. For example, 1 kg of water at 20℃ at normal temperature rises to 60℃ at 19.932kpa.

[0048] Q 1m =C1*M*ΔT1; ΔT=T 2m -T 1m Heat capacity C: J / Kg.℃

[0049] Q 2m =M*ΔH1; ΔH: evaporation enthalpy (heat of vaporization) of liquid J / Kg

[0050] Q m =Q 1m +Q 2m

[0051] Take 1 kg of water at room temperature of 20°C and heat it to 100°C under atmospheric pressure.

[0052] Q 1M =C*M*ΔT2; ΔT=T 2M -T 1M Heat capacity C: J / Kg.℃

[0053] Q 2M =M*ΔH2;

[0054] Q M =Q 1M +Q 2M

[0055] Q=Q M -Q m ≈2036J

[0056] 2036=G*ΔH+C*G*ΔT

[0057] G≈2.7

[0058] After calculation, about 2.7g of water vapor in 1kg of water turns back into water due to insufficient enthalpy.

[0059] The water generated due to sufficient enthalpy value is transported to the heat exchanger 1 through the pipeline system and then through the one-way solenoid valve 5, thereby separating the water vapor from the water and reducing the reduction in the thermal efficiency of the equipment. The water vapor side is transported to the steam pipe through the pipeline, and the equipment requiring steam heating is heated through the steam pipe. The remaining unused water vapor is discharged into the semi-enclosed water tank 4. The 100°C water vapor exchanges heat with the outside air. After the water vapor exchanges heat with the outside cold air, the water vapor becomes water and falls to the bottom of the semi-enclosed water tank 4.

[0060] When high-temperature steam is needed, the pressure of the safety valve 6 is adjusted to 1.5Mpa. By starting the vacuum pump 2, the gas molecules are discharged into the steam pipe between the safety valve 6 and the vacuum pump 2 through mechanical movement. The exhaust rate of the vacuum pump 2 gradually increases, so that the internal pressure in the steam pipe gradually increases until it reaches 1.5Mpa. The energy required for 1 kg of water at room temperature of 20℃ to rise to 121℃ at 1.5Mpa is:

[0061] Q 1k =C*M*ΔT3; ΔT3=T 1k -T 2k Heat capacity C: J / Kg.℃

[0062] Q 2k =M*ΔH;

[0063] Q K =Q1k +Q 2k

[0064] Q=Q K -Q m ≈146.758KJ

[0065] Q E =G2*ΔH+C*G2*ΔT

[0066] G2≈6.4

[0067] It is calculated that about 6.4g of water vapor in 1kg of water turns back into water due to insufficient enthalpy. The water flows to the heat exchanger 1 through the one-way solenoid valve 5. The 121℃ water vapor is discharged from the safety valve 6 and is used for industrial equipment that requires steam, such as heating and sterilization. After the water vapor is used in industry and the equipment is used, the residual heat will condense in the atmosphere and fall into the semi-enclosed water tank 4.

[0068] Embodiment 2:

[0069] See also Figure 1-Figure 4 On the basis of the first embodiment, the output end pipeline of the safety valve 6 is connected to the semi-enclosed water tank 4, a steam pipeline is arranged between the safety valve 6 and the semi-enclosed water tank 4, and condensed water exists inside the semi-enclosed water tank 4.

[0070] The pipe connection at the output end of the vacuum pump 2 is arranged on the upper side of the water interface of the semi-enclosed water tank 4 .

[0071] The output end pipe of the semi-enclosed water tank 4 is connected to the input end of the water inlet valve 3, and the output end pipe of the semi-enclosed water tank 4 is arranged below the horizontal surface of the water inside the semi-enclosed water tank 4. The pipe materials of the pipe system are all insulating materials.

[0072] Working process: Water flows from the semi-enclosed water tank 4 through the pipeline to the water inlet valve 3. The water flows through the water inlet valve 3 to provide sufficient steam water for the heat exchanger 1, so that the whole cycle continues.

[0073] refer to Figure 3 , the overall energy exchange process: water flows from the semi-enclosed water tank 4 to the water inlet valve 3, and then transports a sufficient amount of evaporation water to the heat exchanger 1 through the water inlet valve 3. The water absorbs heat energy Q1, turning the water into steam, and the heat exchanger 1 produces a sufficient amount of water vapor. At this time, from point A to B in the figure, the water vapor passes through the vacuum pump 2, so that from point B to point C in the figure, and then is transported to the steam pipe through the pipeline system, and the equipment that needs steam outputs water vapor through the safety valve 6, and outputs heat Q2 to the outside. From point C to point D in the figure, the unused water vapor contacts with the air, exchanges heat, and falls into the semi-enclosed water tank 4, thereby releasing heat Q3 (Q1=Q2+Q3) to the outside of the system, so that from point C to A, after the water vapor is used up, the water vapor turns into water again, thus continuously circulating.

[0074] The entire cycle uses water as the refrigerant, which can provide society with cleaner and cheaper steam, thereby greatly reducing the cost of steam plants in producing steam and reducing their carbon dioxide emissions.

[0075] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. A negative pressure evaporative heating system based on R718, characterized in that: The invention comprises a heat exchanger (1), a vacuum pump (2), a water inlet valve (3) and a pipeline system. The heat exchanger (1) uses low-quality thermal energy and adopts a low-temperature boiling method for water, so that the water absorbs the low-quality thermal energy and turns into steam. The vacuum pump (2) is used to extract water vapor and maintain the pressure inside the heat exchanger (1). The water inlet valve (3) is used to control the inlet and outlet of condensed water.

2. The negative pressure evaporative heating system based on R718 according to claim 1, characterized in that: The output end of the heat exchanger (1) is connected to the input end of the vacuum pump (2) through a pipeline.

3. The negative pressure evaporative heating system based on R718 according to claim 1, characterized in that: The heat exchanger (1) adopts a high-efficiency tank heat exchanger, and a high-temperature pressure detector is arranged inside the heat exchanger (1).

4. The negative pressure evaporative heating system based on R718 according to claim 1, characterized in that: The vacuum pump (2) is a dry screw vacuum pump.

5. The negative pressure evaporative heating system based on R718 according to claim 1, characterized in that: The water inlet valve (3) is a negative pressure water inlet solenoid valve.

6. The negative pressure evaporative heating system based on R718 according to claim 1, characterized in that: The output end of the water inlet valve (3) is connected to the input end of the heat exchanger (1) through a pipeline.

7. The negative pressure evaporative heating system based on R718 according to claim 1, characterized in that: The output end of the vacuum pump (2) is connected to a one-way solenoid valve (5), the output end of the vacuum pump (2) is connected to a safety valve (6), and the output end of the one-way solenoid valve (5) is connected to the input end of the heat exchanger (1).

8. The negative pressure evaporative heating system based on R718 according to claim 7, characterized in that: The output end pipeline of the safety valve (6) is connected to a semi-enclosed water tank (4), a steam pipeline is provided between the safety valve (6) and the semi-enclosed water tank (4), and condensed water exists inside the semi-enclosed water tank (4).

9. The negative pressure evaporative heating system based on R718 according to claim 7, characterized in that: The pipe connection at the output end of the safety valve (6) is arranged on the upper side of the water interface of the semi-enclosed water tank (4).

10. The negative pressure evaporative heating system based on R718 according to claim 9, characterized in that: The output end pipe of the semi-enclosed water tank (4) is connected to the input end of the water inlet valve (3), and the output end pipe of the semi-enclosed water tank (4) is arranged below the horizontal surface of the water inside the semi-enclosed water tank (4). The pipe materials of the pipe system are all heat-insulating materials.

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