Negative pressure evaporation heating system based on R32 and R718

Abstract

The utility model discloses a negative pressure evaporation heating system based on R32 and R718, which comprises a heating system, a refrigerating system and a pipeline system, the heating system comprises a first heat exchanger, the first heat exchanger is connected with the refrigerating system to form a circulation loop, and the pipeline system is arranged between components in the heating system and the refrigerating system. According to the negative pressure evaporation heating system based on the R32 and 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 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 steam, in particular to a negative pressure evaporation heating system based on R32 and R718. Background Art

[0002] The existing technology is a cascade low-temperature heat pump based on R410A refrigerant, and the high-temperature heat pump adopts R245FA refrigerant. Heat exchange between high and low-temperature heat pumps is carried out in the heat exchanger, and the low-temperature refrigerant is used to heat the high-temperature refrigerant in a fully closed state. This results in the R410A-R245FA steam generation system requiring a separate secondary condenser to be set up when using steam generation, and an additional flash tank is required. The condenser needs to be used together with the flash evaporator to produce steam. The produced steam pressure is insufficient and must pass through a steam compressor to enter the steam pipeline and be effectively transported, which makes the overall structure complex, resulting in low heating efficiency, and the overall structure is large and occupies a large area.

[0003] R410A is a low-temperature refrigerant. It is based on an azeotropic structure. Therefore, if there is a leak, the refrigerant in the entire system must be emptied and refilled. This is acceptable in a small household system, but in a large steam generating system weighing more than ten kilograms, refilling the refrigerant in the entire system will cause serious resource consumption.

[0004] To this end, the utility model provides a negative pressure evaporation heating system based on R32 and R718 to solve the above problems. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides a negative pressure evaporation heating system based on R32 and R718, which solves the above problems.

[0006] To achieve the above objectives, the utility model is implemented through the following technical solutions: a negative pressure evaporation heating system based on R32 and R718, including a heating system, a refrigeration system and a piping system, the heating system includes a first heat exchanger, the first heat exchanger is connected to the refrigeration system to form a circulation loop, and the piping system is arranged between components in the heating system and the refrigeration system.

[0007] Preferably, the output end of the first heat exchanger is connected to a vacuum pump, and the pipeline system is made of insulating material.

[0008] Preferably, the heating system further comprises a one-way solenoid valve, the output end of the vacuum pump is connected to the input end of the one-way solenoid valve, a high temperature pressure detector is arranged inside the first heat exchanger, and the output end of the one-way solenoid valve is connected to the input end of the first heat exchanger.

[0009] Preferably, the heating system also includes a semi-enclosed water tank, the output end of the vacuum pump is connected to a safety valve, a steam pipe is arranged between the vacuum pump and the semi-enclosed water tank, condensed water exists inside the semi-enclosed water tank, and 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.

[0010] Preferably, the output end of the semi-enclosed water tank is connected to a water inlet valve via a pipeline, the pipeline at the output end of the semi-enclosed water tank is arranged on the lower side of the water interface, and the output end of the water inlet valve is connected to the input end of the first heat exchanger.

[0011] Preferably, the refrigeration system includes a second heat exchanger, the output end of the second heat exchanger is connected to a compressor, the output end of the compressor is connected to the input end of the first heat exchanger, the output end of the first heat exchanger is connected to an expansion valve through a pipeline, and the output end of the expansion valve is connected to the input end of the second heat exchanger.

[0012] Beneficial Effects

[0013] The utility model provides a negative pressure evaporation heating system based on R32 and R718. Compared with the prior art, it has the following beneficial effects:

[0014] 1. The negative pressure evaporation heating system based on R32 and 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 present invention 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 with a vacuum pump, which reduces the system pressure, cost and production design requirements, and reduces the floor space.

[0015] 2. The negative pressure evaporation heating system based on R32 and R718 adopts an open reverse Carnot cycle. The steam generation is carried out directly in the system, and there is no heat exchange with the back end. The separation, temperature and pressure of the steam can be directly provided by the vacuum pump, and the refrigerant is no longer required to provide an additional temperature difference. There is no need for a flash tank and a condenser for heat exchange and separation, which reduces the temperature difference required to create a reverse Carnot cycle heat pump, and completely eliminates the circulating water pump required for the flash tank, reducing the number of heat conduction times and effectively improving the efficiency of steam generation.

[0016] 3. The negative pressure evaporation heating system based on R32 and 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, increasing the safety of the entire system.

[0017] 4. The negative pressure evaporation heating system based on R32 and 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, reducing production costs.

[0018] 5. The negative pressure evaporation heating system based on R32 and 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.

[0019] 6. This negative pressure evaporation heating system based on R32 and R718 uses an open reverse Carnot cycle and R718 as the first application of 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.

[0020] 7. The negative pressure evaporation heating system based on R32 and R718 adopts R32 refrigerant, which can avoid the situation that the refrigerant of the entire system must be emptied and refilled as long as there is a leak because it is a refrigerant based on an azeotropic structure. In addition, R32 has better latent heat of vaporization and global warming potential than the existing refrigerant R410A, and the demand for R32 is less than that of R410A. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the overall system principle diagram of the utility model;

[0022] Figure 2 It is a refrigeration system diagram of the utility model;

[0023] Figure 3 It is a heating system diagram of the utility model;

[0024] Figure 4 It is the principle diagram of the heating system of the utility model;

[0025] Figure 5 It is a diagram of the relationship between pressure and volume in the refrigeration system of the utility model;

[0026] Figure 6 It is a diagram showing the relationship between pressure and volume in the heating system of the utility model.

[0027] In the figure:

[0028] 11. First heat exchanger; 12. Vacuum pump; 13. Water inlet valve; 14. Semi-enclosed water tank; 15. One-way solenoid valve;

[0029] 21. Second heat exchanger; 22. Compressor; 23. Expansion valve. DETAILED DESCRIPTION

[0030] 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.

[0031] Embodiment 1:

[0032] See also Figure 1-Figure 6 A negative pressure evaporation heating system based on R32 and R718 includes a heating system, a refrigeration system and a piping system. The heating system includes a first heat exchanger 11. The first heat exchanger 11 is connected to the refrigeration system to form a circulation loop. The piping system is arranged between components in the heating system and the refrigeration system. The refrigerant in the refrigeration system is R32.

[0033] The output end of the first heat exchanger 11 is connected to a vacuum pump 12, and the pipeline system is made of heat-insulating materials.

[0034] The heating system also includes a one-way solenoid valve 15 , the output end of the vacuum pump 12 is connected to the input end of the one-way solenoid valve 15 , a high temperature pressure detector is arranged inside the first heat exchanger 11 , and the output end of the one-way solenoid valve 15 is connected to the input end of the first heat exchanger 11 .

[0035] The heating system also includes a semi-enclosed water tank 14. The output end of the vacuum pump 12 is connected to a safety valve 16. A steam pipe is arranged between the vacuum pump 12 and the semi-enclosed water tank 14. Condensed water exists inside the semi-enclosed water tank 14. The pipe connection at the output end of the vacuum pump 12 is arranged on the upper side of the water interface of the semi-enclosed water tank 14.

[0036] The output end of the semi-enclosed water tank 14 is connected to the water inlet valve 13 through a pipeline. The pipeline at the output end of the semi-enclosed water tank 14 is arranged at the lower side of the water interface. The output end of the water inlet valve 13 is connected to the input end of the first heat exchanger 11.

[0037] The refrigeration system includes a second heat exchanger 21, the output end of the second heat exchanger 21 is connected to a compressor 22, the output end of the compressor 22 is connected to the input end of the first heat exchanger 11, the output end of the first heat exchanger 11 is connected to an expansion valve 23 through a pipeline, and the output end of the expansion valve 23 is connected to the input end of the second heat exchanger 21.

[0038] Working principle: Low-grade heat energy, i.e. heat energy with a temperature of more than 60°C, is introduced into the first heat exchanger 11, and the first heat exchanger 11 performs heat exchange. The water in the first heat exchanger 11 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 first heat exchanger 11 is heated, and the vacuum pump 12 is started. Through mechanical movement, gas molecules are absorbed from the first heat exchanger 11 and gradually discharged into the pipeline system. The exhaust rate of the vacuum pump 12 gradually increases, so that the first heat exchanger 11 gradually reduces the internal gas, thereby reducing the gas pressure inside the first heat exchanger 11, making it impossible for the extracted gas to flow back, maintaining a negative pressure state in the first heat exchanger 11, and detecting the pressure inside the first heat exchanger 11 in real time through a high-temperature pressure detector.

[0044] When the high-temperature pressure detector detects that the internal pressure of the first heat exchanger 11 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 12 and the water inlet valve 13. Even if the pipeline is broken, it will only cause decompression, thereby increasing the safety of the entire system.

[0045] At this time, the mechanical movement rate of the vacuum pump 12 is controlled so that the gas pressure inside the first heat exchanger 11 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), 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 the first heat exchanger 11. When the water vapor passes through the vacuum pump 12, at 19.932Kpa, the water vapor enters the normal pressure (atmospheric pressure) from the low pressure state. Because of 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. Finally, part of the 60°C water vapor condenses into water due to insufficient energy, and the other steam absorbs energy and is converted into a state that can exist stably at room temperature (that is, the compression and self-absorption of water vapor, from 60°C to 100°C stable existence, and 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 first heat exchanger 11 through the pipeline system and then through the one-way solenoid valve 15, so as to separate the water vapor from the water and reduce 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 14, and 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 turns into water and falls to the bottom of the semi-enclosed water tank 14.

[0060] Water flows from the semi-enclosed water tank 14 to the water inlet valve 13 through the pipeline. The water flows through the water inlet valve 13 to provide sufficient steam water for the first heat exchanger 11, so that the whole is continuously circulated.

[0061] refer to Figure 6 , the overall energy exchange process: water flows from the semi-enclosed water tank 14 to the water inlet valve 13, and then a sufficient amount of water for evaporation is transported to the first heat exchanger 11 through the water inlet valve 13. The water absorbs heat energy Q1, turning the water into steam. The first heat exchanger 11 generates a sufficient amount of water vapor. At this time, from point A to point B in the figure, the water vapor passes through the vacuum pump 12, so that from point B to point C in the figure, and then is transported to the steam pipe through the pipeline system, and then outputs the water vapor to the equipment that needs steam through the steam pipe, 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 14, thereby releasing heat Q3 (Q1=Q2+Q3) to the outside of the system, so that from point C to point A, after the water vapor is used up, the water vapor turns into water again, thus continuously circulating.

[0062] Refrigeration system:

[0063] refer to Figure 5 The refrigerant disposed inside the second heat exchanger 21 is R32, which has a higher cooling efficiency and can provide a faster and more powerful cooling effect. R32 has a lower combustion potential and a lower fire risk than other refrigerants.

[0064] The entire refrigeration system pipeline is pressurized, causing the refrigerant in the refrigeration system to change from a normal temperature gas to a liquid state.

[0065] Based on the first heat exchanger 11, R32 and R718 realize heat transfer through indirect heat exchange, so that the temperature of R32 is output to the outside Q0, so that the high-temperature steam becomes a high-temperature liquid, from point D1 to point A1 in the figure. The refrigerant R32 passes through the expansion valve 23 through the pipeline system, so that the high-temperature liquid refrigerant becomes a low-temperature liquid-vapor mixture through its throttling, from point A1 to point B1 in the figure. The refrigerant is heat exchanged inside the second heat exchanger 21, absorbing external energy Q0, from B1 to C1, so that the refrigerant is changed from a liquid-vapor mixture to a low-temperature steam. The steam is compressed by the compressor 22, from C1 to D1, so that the refrigerant is changed from a low-temperature steam to a high-temperature steam, and the cycle is repeated.

[0066] This technology is based on the combined effect of cascade heat pump technology of R32 refrigerant and negative pressure evaporation of R718 refrigerant, and is applied to steam generators. A more efficient refrigeration system based on R32 refrigerant design is used on the low-temperature side, and a simpler R718 open steam generation system is used on the high-temperature side. It has better low-temperature heating capacity and innovatively uses an open negative pressure reverse Carnot cycle. In the second cycle, this system integrates the heat pump system of the reverse Carnot cycle, and the steam generation and separation system. Compared with traditional designs, it has a higher degree of integration and a smaller volume. At the same time, since there is only water in the high-temperature refrigerant pipeline and no other pollutants, it has very good safety in the food industry, higher efficiency, and optimized production costs.

[0067] In this embodiment, the second heat exchanger 21 can adopt a low-temperature heat exchanger in the prior art, the compressor 22 can adopt a low-temperature compressor in the prior art, the first heat exchanger 11 can adopt an evaporative heat exchanger in the prior art, the vacuum pump 12 can adopt a high-temperature vacuum pump in the prior art, and the water inlet valve 13 can adopt a negative pressure water inlet solenoid valve in the prior art.

[0068] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0069] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0070] 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 defined by the appended claims and their equivalents.

Claims

1. A negative pressure evaporative heating system based on R32 and R718, characterized in that: The invention comprises a heating system, a refrigeration system and a pipe system, wherein the heating system comprises a first heat exchanger (11), the first heat exchanger (11) is connected with the refrigeration system to form a circulation loop, the pipe system is arranged between components in the heating system and the refrigeration system, and the refrigerant in the refrigeration system is R32.

2. According to claim 1, a negative pressure evaporative heating system based on R32 and R718 is characterized in that: The output end of the first heat exchanger (11) is connected to a vacuum pump (12), and the pipeline system is made of heat-insulating materials.

3. The negative pressure evaporative heating system based on R32 and R718 according to claim 2, characterized in that: The heating system further comprises a one-way solenoid valve (15), the output end of the vacuum pump (12) is in communication with the input end of the one-way solenoid valve (15), a high-temperature pressure detector is provided inside the first heat exchanger (11), and the output end of the one-way solenoid valve (15) is in communication with the input end of the first heat exchanger (11).

4. The negative pressure evaporative heating system based on R32 and R718 according to claim 3 is characterized in that: The heating system further comprises a semi-enclosed water tank (14); the output end of the vacuum pump (12) is connected to a safety valve (16); a steam pipe is arranged between the vacuum pump (12) and the semi-enclosed water tank (14); condensed water exists inside the semi-enclosed water tank (14); and a pipe connection at the output end of the vacuum pump (12) is arranged on the upper side of the water interface of the semi-enclosed water tank (14).

5. The negative pressure evaporative heating system based on R32 and R718 according to claim 4 is characterized in that: The output end of the semi-enclosed water tank (14) is connected to a water inlet valve (13) via a pipeline. The pipeline at the output end of the semi-enclosed water tank (14) is arranged below the water interface. The output end of the water inlet valve (13) is connected to the input end of the first heat exchanger (11).

6. The negative pressure evaporative heating system based on R32 and R718 according to claim 1, characterized in that: The refrigeration system comprises a second heat exchanger (21); the output end of the second heat exchanger (21) is connected to a compressor (22); the output end of the compressor (22) is connected to an input end of the first heat exchanger (11); the output end of the first heat exchanger (11) is connected to an expansion valve (23) via a pipeline; the output end of the expansion valve (23) is connected to an input end of the second heat exchanger (21).

Images