WO2009155822A1

WO2009155822A1 - A mixed working fluid for heat pumps

Info

Publication number: WO2009155822A1
Application number: PCT/CN2009/072121
Authority: WO
Inventors: 王高元
Original assignee: Wang Gaoyuan
Priority date: 2008-06-23
Filing date: 2009-06-04
Publication date: 2009-12-30
Also published as: AU2009264496B2; AU2009264496A1; CN101613591A

Abstract

The present invention provides a coolant mixture composed of two or three components. A binary non-azeotropic coolant is composed of 1 to 80 percent by mass of R125 and 20 to 99 percent by mass of R152a. A ternary non-azeotropic coolant is composed of 2 to 50 percent by mass of R125, 15 to 97 percent by mass of R152a and 1 to 35 percent by mass of R143a. The coolant mixture is physically blended at normal temperature in the defined proportion, to obtain the corresponding mixed working fluid. The coolant has an ozone depletion potential (ODP) equal to zero, does not destroy the ozonosphere, can reduce the influence of greenhouse effect and is environmentally friendly. The coolant has appropriate thermal parameters and good cycle performance. The coolant can replace a coolant mixture of dichlorodifluoromethane (CFC12) and dichlorofluoromethane (HCFC22), and can be used in the heat pump systems for that coolant mixture.

Description

Instruction manual

Mixing fluid for heat pump system

Technical field

The present invention relates to a refrigerant mixture, particularly a refrigerant mixture applied to a heat pump system, for replacing a heat pump system containing CFC 12 or HCFC 22 and used in the refrigerant mixture. Background technique

Since 1987, global actions to protect the ozone layer, phase out ODS, and reduce the greenhouse effect are being carried out in countries around the world in accordance with the Montreal Protocol. Our country has begun to actively pursue alternative work, and finding safe, efficient and environmentally friendly alternative refrigerants has become an urgent and important task.

Because CFC-based refrigerants are subject to high ozone depletion potential (ODP), they are tightly controlled in Montreal and subsequent amendments. HCFC-based refrigerants, unlike CFCs, where HCFCs are only partially replaced by halogen atoms, and the remaining hydrogen atoms contribute to the partial decomposition of the chemical in the stratosphere. Therefore, the damage to the ozone layer is relatively small. However, HCFC was listed as a restricted substance at the Copenhagen conference in 1992, which has a great impact on the refrigeration and air-conditioning industry, as the currently widely used HCFC22 will have to be phased out, requiring developed countries to be in 1996. 100% ban on the use and production of CFCs, and the abolition of HCFCs in 2020; developing countries should stop production and consumption of CFCs in full from 2010 and stop the use of HCFCs in 2030. The HFC includes R23, R32, R125, R134a, and R152a.

These hydrocarbon molecules include fluorine and do not include bromine. HFCs are considered to be the first choice for future replacement of HCFCs due to their non-destructive effect on the ozone layer. However, HFC faces the problem of their chemical stability and can be aggregated after release. This may eventually accelerate the global warming. Substances that have been replaced by CFCs half a century ago, such as ammonia (R717), water (R718), air (R729) and carbon dioxide (R744), are now beginning to be renewed as alternatives.

Because of the limited working fluids that are suitable as CFC substitutes, mixed working fluids may be an effective way to solve this problem. The mixed working fluid can be obtained by changing the molar concentration ratio of each component. In the past few years, various refrigerant mixtures have been proposed as alternatives to CFC12 (also known as R12), CFC502 (also known as R502) and HCFC22 (also known as R22), but some of them contain HCFC as a component. Ingredients, according to the Montreal Protocol, their use is prohibited, so in the long run, this refrigerant mixture containing HCFC is not a suitable alternative refrigerant. The present invention relates to a non-azeotropic mixture containing difluoroacetamidine (HFC152a, also known as R152a), pentafluoroacetamidine (HFC125, also known as R125) and trifluoroacetamidine (HFC143a, also known as R143a) in the liquid phase. There is little difference in boiling point between the equilibrium state and the gas phase, and there is great potential for development. The prior art heat pump working fluids are all conventional R12, R22 and some alternative mixed working materials, such as common R407c (R32 I R125 I R134a: 23 / 25 / 52 mass fraction), R417a (R125 I R134a I R600: 47 / 50 / 3 mass fraction), R410a (R32 I R125: 50 I 50 mass fraction), etc. Among them, R407C and R410a are the mixed working fluids in the heat pump system which are very likely to replace R22. The heat pump water heaters with these mixed working fluids can generally raise the water temperature to about 60 °C. Some mixed working fluids suitable for medium and high temperature heat pumps have also been proposed. We will not introduce them here. Some scholars have mixed flammable R152a with a certain amount of non-flammable R125 as a substitute for R22.

To ensure that a particular substance can be used as an alternative refrigerant to an existing refrigerant, the material should have a coefficient of performance (COP) similar to that of existing refrigerants. One way to solve such problems is to use a refrigerant mixture. The refrigerant mixture has an advantage in that the composition of the refrigerant mixture is adjusted by appropriately combining various components to simultaneously obtain a coefficient of performance and a volume capacity (VC) comparable to those of the existing refrigerant, thereby making it unnecessary to operate the compressor Make a big renovation.

The R407C developed by DuPont has the similar cooling capacity of the traditional HCFC22 refrigerant, but its energy efficiency is relatively low, and its temperature slip difference is about 7 °C. The exhaust pressure of R407C is similar to that of R22, and the energy efficiency is close to R22. The advantage is that it can be directly filled (except for the ester oil), but the disadvantage is that the decomposition of the refrigerant may occur, causing refrigerant leakage and adverse effects on other components, when the refrigerant leaks in the refrigeration system. The problem of separation of the components of the refrigerant will occur. In addition, when the slip temperature difference is too large, the phase transition of the refrigerant causes a continuous change in the pressure in the evaporator and the condenser, thereby causing instability of the refrigeration system and ultimately degrading the efficiency of the entire system. This means finding new alternatives. Allied Signal Inc. has developed and sold the R410a. R410a is a near-azeotropic mixture with a temperature slip of no more than 0.2 °C. The exhaust pressure of R410a is 50~60% higher than that of R22, and the volumetric cooling capacity is relatively large, about 1.4~1.5 times that of R22. Therefore, it is not possible to directly fill the compressor. The compressor and main components must be redesigned, which will increase the cost. At the same time, the heat exchanger needs to be re-optimized to accommodate its lower volumetric flow. Therefore, although the R410A is more energy efficient than R22, it is only suitable for newly designed units and cannot be used to replace R22 in existing installations.

According to the vapor pressure screening principle and the basic requirements of working fluid substitution, R152a and R125 were initially selected as the components of the binary mixed working fluid. The vapor pressure curves of R152a and R125 are similar to those of R22. Comparing the thermophysical properties of these two components with the alternative working fluid, the defect of R152a is flammable, and adding a certain amount of non-flammable R125 can inhibit its flammability, although R125 has a higher GWP value, but when it is in the mixture In the case where the proportion in the R152a is much smaller than the GWP value of about 0, the GWP value of the mixture will reach a satisfactory level.

R125 has poor oil solubility, but R152a has good compatibility with polyester lubricants. Therefore, in the case of a small R125 content, the total oil solubility of the mixed working fluid can meet the requirements. In addition, for R152a, R125 In addition, the lubricating oil which can be compatible with both of them is also a polyethylene glycol (PFPE) oil and an oil ester. It is worth noting that: R152a and R125 have ODP values of 0, which is very important for the protection of the ozone layer. Moreover, they belong to the HFC category and have the advantage of long-term substitution.

Binary and ternary mixtures of R143a (HFC-143a) with R32, R134a, and R125 are considered to be the most promising alternatives to refrigerant R22, which is widely used in air conditioners and heat pump units. In recent years, a large number of experimental studies have been conducted on the thermal properties of R143a by relevant personnel at home and abroad.

The present invention relates to R125, R143a and R152a having an ozone depletion potential (ODP) of 0.0, and their global warming potential (GWP) is significantly lower than other refrigerants. In view of this characteristic, the European Union (EU), Japan and most Asian countries have made a lot of attempts to combine refrigerants with ODP values of 0.0 and lower GWP than conventional CFC or HFC refrigerants in order to obtain the desired thermodynamic properties. At the same time improve efficiency and compatibility with oil. From this point of view, it can be considered that propylene, propionium, isobutyl hydrazine, DME and HFC152a can achieve this purpose. However, the prior art often regards R125 and R152a as a selected component, ignoring the unexpected effects of combining it into a mixed working medium.

At present, many countries have put a lot of effort into the development of alternative working fluids for R22, especially for non-azeotropic mixed refrigerants that are originally present in the environment, safe and pure refrigerants. s concern. In the cooling and heating cycle, the amount of cooling or heating is an important parameter to the COP. If the refrigerant capacity of the alternative refrigerant is too different from R22, the compressor size must be redesigned at a high cost. Therefore, the refrigerant capacity of the alternative refrigerant must be similar to that of R22.

The refrigerant mixture according to the present invention mainly contains difluoroacetamidine (R152a;), pentafluoroacetic acid (R125) and trifluoroacetamidine (R143a;). More specifically, the present invention also relates to a refrigerant mixture capable of replacing dichlorodifluoromethane (R12) and difluoromonochloroformamidine (R22) and a refrigeration system for use in the refrigerant mixture, the dichloro Difluoromethane is now widely used in household refrigerators and vehicle air conditioners, and the difluorochloromethane is widely used in household and commercial air conditioners. Summary of the invention

The object of the present invention is to develop a novel refrigerant mixture which can be used without replacing an existing refrigeration system selected from the group consisting of difluoroacetic acid (R152a;), pentafluoroacetic acid (R125) and A refrigerant mixture of two or three components of trifluoroacetic acid (R143a) has an ozone depletion potential (ODP) of 0.0 and their global warming potential (GWP) is also low. It can basically reduce the ozone layer, reduce the greenhouse effect, meet the environmental protection requirements; and is non-toxic, low flammable, especially its thermal performance and thermal parameters are good, can directly use R12 or R22 refrigeration system in heat pump, compressor No need to change with the main components in the system The production line does not need to be modified, and the miscibility with the lubricant is good.

The refrigerant mixture of the present invention comprises: R152a and R125 refrigerant composition working fluids, R152a, R125 and R143a refrigerant composition working fluids; more particularly, the present invention relates in particular to a heat pump type heat exchange system. Similarly, its low-temperature evaporation performance is also excellent, and its working performance below -5 °C has a high COP value. The present invention also relates to the ability to replace dichlorodifluoromethane (R12) and difluoro-chloroformamidine (R22). a refrigerant mixture and a heat pump system using the refrigerant mixture, which is widely used in household refrigerators and vehicle air conditioners, and the difluorochloromethane is widely used in household and commercial air conditioners. .

The formulation of the present invention mainly comprises: R125 and R152a refrigerant composition working medium, the mass ratio of R125 and R152a is: R125: l-80%, R152a: 20-99%.

The working composition of the binary non-azeotropic refrigerant composition is: R125: 2-50%, R152a _: 50-98%. Binary non-azeotropic refrigerant, composition R125: 5-14%, R152a _: 86-95%.

Binary non-azeotropic refrigerant, composition R125: 35-65%, R152a: 35-65%.

R125, R152a and R143a ternary non-azeotropic refrigerant composition working fluid; R125, R152a and R143a mass percentages are: R125: 2-50%, R152a: 15-97%, R143a _: 1-35%.

The ternary non-azeotropic refrigerant is in R125: 2-35%, R152a: 64-97% R143a _: 1-10%. Composition of ternary non-azeotropic refrigerant, R125: 1-80%, R152a _: 20-97%, R143a _: 1-5%. Composition of ternary non-azeotropic refrigerant, R125: 5-15%, R152a _: 85-94%, R143a _: 1-5% ternary non-azeotropic refrigerant composition, R125: 35-64%, R152a: 35-65 %, R143a _: 1-5% The above mixed working fluid is suitable for heat pumps and their extension products.

The preparation method comprises the physical mixing of the above components in a liquid phase state according to their respective ratios.

The beneficial effects of the invention are:

(1) The temperature slip is small.

(2) Good environmental performance, not only the ozone depletion potential ODP value is zero, but also the global warming potential is less than R22 and the existing main substitute R407C, which meets environmental protection requirements and becomes the biggest advantage of the present invention.

(3) With the change of mixing ratio, the thermal parameters of the mixture change regularly. The thermal parameters such as operating pressure and pressure ratio can be similar to those of R12 and R22. The compressor corresponding to R12 or R22 can be used directly. The invention separately designed the compressor separately. It can be directly filled when replacing R12 or R22 refrigerant, and the heat per unit volume is equivalent to R12 or R22, and the amount of filling can be reduced. Thermal performance such as unit mass heat is better than R12, R22, exhaust temperature is also less than R22, COP is equivalent to R12, R22, can be used as a long-term replacement for R12, R22. The present invention aims to develop a novel refrigerant which can be used in place of R12 or R22 so that the newly developed refrigerant not only does not destroy the ozone layer, but also has a smaller greenhouse effect. In addition, it has the same thermal parameters and thermal properties as R12 or R22, and can be used as a direct substitute for R12 or R22.

The novel refrigerant which can be used in place of R12, R22 provided by the present invention is characterized in that the refrigerant is selected from the group consisting of difluoroacetamidine (R152a;), pentafluoroacetamidine (R125) and trifluoroacetamidine (R143a). A refrigerant mixture of a combination of two or three components.

The binary non-azeotropic mixture R125 and R152a mass percentages are: R125: 1-80%, R152a: 20-99%. After adding R143a, a ternary non-azeotropic mixture is formed, and the mass ratio of R143a added is 1-35%. The mass percentage of the ternary mixture of R125, R152a and R143a is:

R125: 2-50%, R152a: 35-97%, R143a _: 1-35%.

The refrigerant provided by the present invention is prepared by physically mixing the above various components in a liquid phase state according to their respective ratios.

Table 1-1 Comparison of thermophysical properties of R152a, R125 and R143a with R22

Table 1-2 Comparison of thermophysical properties of R152a, R125 and R143a with R22 and R407C

— ODP uses CFC-11 as the reference value of 1.0.

— GWP is based on CO2 (100-year time level) as a reference value of 1.0.

Comparison of performance analysis of binary refrigerant mixtures of R125 and R152a.

Example A1: R125 and R152a were physically mixed in a liquid phase at a mass of 5:95: percentage.

Example A2: R125 and R152a were physically mixed in a liquid phase at a mass of 10:90: percentage.

Example A3: R125 and R152a were physically mixed in the liquid phase at a mass of 14:86: percentage.

Example A4: R125 and R152a were physically mixed in the liquid phase at a mass of 20:80: percentage.

Example A5: R125 and R152a were physically mixed in the liquid phase at a mass: percentage of 28:72. Example A6: R125 and R152a were physically mixed in a liquid phase at a mass percentage of 35:65. Example A7: R125 and R152a were physically mixed in a liquid phase at a mass percentage of 40:60. Example A8: R125 and R152a were physically mixed in a liquid phase at 50:50 by mass. Example A9: R125 and R152a were physically mixed in a liquid phase at a mass percentage of 65:35. Example A10: R125 and R152a were physically mixed in a liquid phase at a mass percentage of 80:20.

Comparison of performance analysis of ternary refrigerant mixtures of R125, R152a and R143a.

Example B1: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 2:97:1.

Example B2: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 10:89:1.

Example B3: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 20:75:5.

Example B4: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 35:64:1.

Example B5: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 35:60:5.

Example B6: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 40:52:8.

Example B7: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 45:45:10.

Example B8: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 41:41:18.

Example B9: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 35:40:25.

Example B10: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 45:25:30.

Example B11: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 30:35:35.

Example B12: R125, R152a and R143a were physically mixed in a liquid phase at a mass percentage of 50:15:35.

The performance of the above embodiment is now compared with R12, R22 and its main alternative R407C to illustrate the features and effects of the present invention.

Comparison of temperature slip (unit: °C)

Example A10 - 43.81 - 38.8 5.10 Example B12 - 44.15 - 41.1 3.05 Example Bl - 25.08 - 24.34 0.74 R407C - 43.63 - 36.63 7.00 Example B2 -27.48 - 25.15 2.33

Note: The bubble point temperature and dew point temperature in the table are both saturated at a standard atmospheric pressure of 101.325 kPa.

As can be seen from the table, the temperature slip of all the examples is less than R407C, and there is no problem in commercial use.

Environmental performance

The following table compares the environmental performance of the above examples with R22 and R407C, wherein the ODP value is CFC-11 as the reference value of 1.0, and the GWP value is C0 ₂ as the reference value of 1.0 (100 years).

Table 3 Comparison of environmental performance

As can be seen from the table, the ozone layer depletion potential (ODP) value of the above embodiment is zero, and has no destructive effect on the atmospheric ozone layer, which is superior to R12 and R22.

Moreover, the global warming potential (GWP) value of the above implementation A1-A7 is less than R22, only 17%~84% of R22. It is 19%~93% of the R407CGWP value, which is more in line with the current environmental protection requirements for protecting the ozone layer and reducing the global warming effect.

Moreover, the global warming potential (GWP) values of the above-mentioned embodiments B1-B8 are equivalent to those of R22 and R407C, and are in line with the current environmental protection requirements for protecting the ozone layer and reducing the global warming effect.

Thermal parameters and thermal performance

The invention calculates the thermal property parameters of the mixture with different ratios by using the physical property calculation software commonly used in the world, and theoretically compares and compares the performance of the heat pump thermodynamic cycle using different proportion mixture at an average evaporation temperature of 5 ° C, as shown in the table. Figure 4-1 shows.

Table 4-1 Performance comparison between R12, R22 and alternative refrigerant mixtures

- 1 - Example A6 1.5199 0.3744 4.0596 235.56 54.93 4.29 Example A7 1.5759 0.3869 4.0731 226.15 53.32 4.24 Example A8 1.6948 0.4166 4.0682 206.97 49.76 4.16 Example A9 1.8945 0.4781 3.9626 177.24 43.53 4.07 Example A10 2.1301 0.5726 3.7201 146.27 36.24 4.04 Example B1 1.2060 0.3190 3.7806 293.52 62.54 4.69 Example B2 1.2788 0.3301 3.8740 279.65 61.15 4.57 Example B3 1.4201 0.3557 3.9924 256.71 58.42 4.39 Example B4 1.5316 0.3773 4.0594 234.24 54.75 4.28 Example B5 1.5784 0.3895 4.0524 228.80 53.86 4.25 Example B6 1.6710 0.4142 4.0343 215.10 51.35 4.19 Implementation Example B7 1.7552 0.4393 3.9954 202.51 48.79 4.15 Example B8 1.8036 0.4589 3.9303 198.88 47.96 4.15 Example B9 1.8155 0.4663 3.8934 200.56 48.24 4.16 Example B10 2.0064 0.5431 3.6943 173.09 41.82 4.14 Example B11 1.8760 0.4926 3.8084 196.33 47.08 4.17 Example B12 2.1451 0.6102 3.5154 155.46 37.47 4.15

R22 1.9427 0.5841 3.3260 197.24 42.89 4.60

R12 1.2166 0.3620 3.3608 144.7 30.89 4.68

R407C 2.2160 0.3853 5.7514 217.06 64.86 3.35 In order to compare the performance of the heat pump at ambient temperature in winter, the theoretical calculation of the average evaporation temperature at 5 °C is also given, as shown in Table 4-2. Table 4-2 Comparison of performance between R12, R22 and alternative refrigerant mixtures

Example B5 1.4017 0.2733 5.1288 240.36 63.24 3.80 Example B6 1.4855 0.2912 5.1013 226.25 60.29 3.75 Example B7 1.5615 0.3095 5.0452 213.27 57.33 3.72 Example B8 1.6051 0.3241 4.9825 209.64 56.39 3.72 Example B9 1.6159 0.3297 4.9011 211.57 56.82 3.72 Example B10 1.7873 0.3873 4.6148 183.26 49.42 3.71 Example B11 1.6705 0.3495 4.7797 206.91 55.54 3.73 Example B12 1.9115 0.4386 4.3582 165.09 44.36 3.72

R22 1.7292 0.4218 4.0996 207.87 50.73 4.10

R12 1.0821 0.2606 4.1523 150.68 36.25 4.16

R407C 1.9723 0.3853 5.1189 208.61 57.25 3.64 As can be seen from Table 4, in the above Examples A1-A7, as the R125 content increases, the COP of the mixture decreases while the slip temperature difference increases, and as shown in Table 2, the mixture increases with the R125 content. The slip temperature difference is significantly increased.

The condensing pressure, evaporation pressure, and pressure ratio of the above embodiments A1-A3 are similar to those of R12, and are in an allowable range. Moreover, their unit volume of heat is equivalent to R12, which means that the embodiment can directly use the R12 compressor without The compressor is specially designed for the present invention. It can be directly filled when used to replace R12 refrigerant. The condensing pressure, evaporation pressure, and pressure ratio of Examples A7-A9 are close to R12, and are in the allowable range, but the heat per unit volume is less than R22, and the COP value of all the examples is larger than the substitute R407C of R22, which is equivalent to R12 and R22. .

The condensing pressure, evaporation pressure, and pressure ratio of the above embodiments B1-B4 are similar to those of R12, and are in an allowable range, and can be directly filled when replacing the R12 refrigerant.

Claims

Claims, a binary non-azeotropic refrigerant, characterized by a mass percentage consisting of the following components: R125:

1- 80%, R152a _: 20-99%.

The binary non-azeotropic refrigerant according to claim 1, wherein the composition is R125: 2-50%, R152a: 50-98%.

The binary non-azeotropic refrigerant according to claim 1, wherein the composition is R125: 5-14%, R152a _:

86-95%.

The binary non-azeotropic refrigerant according to claim 1, wherein the composition is R125: 35-65%, R152a _:

35-65%.

A ternary non-azeotropic refrigerant characterized by a mass percentage consisting of the following components: R125:

2- 50%, R152a: 15-97%, R143a: 1-35%.

The ternary non-azeotropic refrigerant according to claim 5, wherein R125: 2-35%, R152a: 64-97%;

R143a _: 1-10%.

The ternary non-azeotropic refrigerant according to claim 5, wherein R125: 1-80%, R152a: 20-97%,

R143a _: 1-5%.

The ternary non-azeotropic refrigerant according to claim 5, wherein R125: 5-15%, R152a: 85-94%, and R143a _: 1-5%.

The ternary non-azeotropic refrigerant according to claim 5, wherein R125: 35-64%, R152a: 35-65%,

R143a _: 1-5%.

0. The mixed working fluid of one of claims 1-9 is suitable for use in a heat pump and its extension products.