HEAT TRANSFER METHODS, SYSTEMS AND COMPOSITIONS

Abstract

Disclosed are refrigerants comprising at least about 97% by weight of a blend of three compounds, said blend consisting of:

from about 38% by weight to about 48% by weight difluoromethane (HFC-32),
from about 6% by weight to about 12% by weight pentafluoroethane (HFC-125),
from about 33% by weight to about 41% by weight trifluoroiodomethane (CF.sub.3I) and
from about 2% by weight to about 16% by weight 2,3,3,3-tetrafluoropropene (HFO-1234yf)
wherein the percentages are based on the total weight of the three compounds in the blend, and methods and systems which use same.

Claims

1-30. (canceled)

31. A refrigerant comprising at least about 99.5% by weight of a blend of four compounds, said blend consisting of: from about 46% by weight to less than 48% by weight difluoromethane (HFC-32),from about 11% by weight to about 12% by weight pentafluoroethane (HFC-125), from about 34% by weight to about 36% by weight trifluoroiodomethane (CF3I) and from about 5% by weight to about 7% by weight 2,3,3,3-tetrafluoropropene (HF0-1234yf), wherein the percentages are based on the total weight of the four compounds in the blend and wherein said refrigerant composition has: (a) a HFC32+HF01234yf:CF3I+HFC125 ratio of from greater than about 1:1 to less than 1.2:1; and (b) an evaporator glide of less than 2° C.

32. The refrigerant of claim 31 wherein said blend consists of: 47% by weight difluoromethane (HFC-32), 12% by weight pentafluoroethane (HFC-125), 35% by weight trifluoroiodomethane (CF3I) and 6% by weight 2,3,3,3-tetrafluoropropene (HF0-1234yf), wherein the percentages are based on the total weight of the four compounds in the blend.

33. The refrigerant of claim 31 wherein the refrigerant consists of said blend.

34. The refrigerant of claim 31 wherein the weight ratio of (HFC-32+HFO-1234yf):(CF3I+HFC-125) is from greater than about 1.1:1 to about 1.18:1.

35. The refrigerant of claim 31 wherein the weight ratio of HFC-32:HFC-125 from greater than 3.5:1 to about 4:1, preferably from about 3.8:1 to about 3.9:1.1.

36. A heat transfer composition comprising the refrigerant of claim 31.

37. The heat transfer composition of claim 36 further comprising a stabilizer selected from a diene based compound, or a diene based compound and a phosphorous compound, and/or a nitrogen compound and/or a phenolcompound.

38. The heat transfer composition of claim 37 wherein the stabilizer composition comprises a diene based compound.

39. The heat transfer composition of claim 37 wherein the stabilizer composition comprises farnesene.

40. A heat transfer composition comprising a refrigerant as claimed in claim 31 and a stabilizer composition, wherein the stabilizer composition consists of BHT in an amount of from about 0.001% by weight to about 5% by weight.

41. A heat transfer composition comprising a refrigerant as claimed in claim 31 and a stabilizer composition, wherein the stabilizer composition comprises BHT.

42. The heat transfer composition of claim 41 further comprising a lubricant selected from the group consisting of polyol esters (POEs), polyalkylene glycols (PAGs), PAG oils, silicone oils, mineral oil, alkylbenzenes (ABs),polyvinyl ethers (PVE) and poly(alpha-olefin) (PAO).

43. The heat transfer composition of claim 42 wherein the lubricant is a polyol ester (POE).

44. The heat transfer composition of claim 31 wherein said refrigerant has a Global Warming Potential (GWP) of not greater than 750 and an evaporator glide of less than 1.5° C.

45. A method of cooling comprising including in an air conditioning system the heat transfer composition of claim 43.

46. The method as claimed in claim 45 wherein the air conditioning system is a mobile air conditioning system.

47. The method as claimed in claim 46 wherein the air conditioning system is a residential air-conditioning system having an evaporator temperature in the range of about 0 to about 10° C.

48. The method as claimed in claim 46 wherein the air conditioning system is a low temperature refrigeration system having an evaporator temperature in the range of about −40 to about −12° C.

49. A method of replacing an existing refrigerant contained in a heat transfer system comprising removing at least a portion of said existing refrigerant from said system, said existing refrigerant being R-410A and replacing at least a portion of said existing refrigerant by introducing into said system a refrigerant according to claim 1.

50. The heat transfer system of claim 49 wherein the heat transfer system is a low temperature refrigeration system having an evaporator temperature in the range of about −40 to about −12° C. and wherein said refrigerant has an evaporator glide of less than 1.5° C.

Description

EXAMPLES

[0625] The following refrigerant compositions were evaluated for their performance in a number of refrigeration systems.

[0626] Refrigerants were prepared by producing a mixture of HFC-32, HFC-125, CF.sub.3I and HFO-1234yf in the amounts indicated in table 1 below.

[0627] Each composition was subjected to thermodynamic analysis to determine its ability to match the operating characteristics of R-410A in various refrigeration systems. The analysis was performed using experimental data collected for properties of the binary pairs. The vapour liquid equilibrium behavior of CF.sub.3I was studied in a series of binary pairs with HFC-32, HFC-125 and HFO-1234yf. The composition was varied over from 0% to 100% for each binary pair in the experimental evaluation. Mixture parameters for each binary pair were regressed to the experimentally obtained data and the parameters were also incorporated into the National Institute of Science and Technology (NIST) Reference Fluid Thermodynamic and Transport Properties Database (Refprop 9.1 NIST Std Database, 2013). The standard mixing parameters already available in Refprop 9.1 were used for other binary pairs. The assumptions used to conduct the analysis are the following: Same compressor displacement for all refrigerants, same operating conditions for all refrigerants, same compressor isentropic and volumetric efficiency for all refrigerants.

TABLE-US-00001 TABLE 1 Refrigerants evaluated for Performance Examples HFC32 HFC-125 CF.sub.3I HFO-1234yf Refrigerant (wt %) (wt %) (wt %) (wt %) 1 48% 12% 34% 6% 2 47% 12% 35% 6% 3 46% 12% 36% 6% 4 44% 12% 38% 6%

TABLE-US-00002 TABLE 2 Properties of Refrigerants 1 to 4 Capacity COP Evap (% of (% of Glide Refrigerant GWP R410A) R410A) (° C.) Flammability OEL 1 745 96% 102% 1.36 Non 547 Flammable 2 738 95% 102% 1.46 Non 537 Flammable 3 731 95% 102% 1.57 Non 527 Flammable 4 718 94% 102% 1.82 Non 509 Flammable

Example 1 Residential Air-Conditioning System (Cooling)

Description:

[0628] Residential air-conditioning systems are used to supply cool air (about 12° C.) to buildings in the summer. Typical system types are split, mini-split, and window air-conditioning system. The system usually has an air-to-refrigerant evaporator (indoor coil), a compressor, an air-to-refrigerant condenser (outdoor coil), and an expansion valve. The evaporator and condenser is usually round tube plate fin or microchannel heat exchanger. The compressor is usually reciprocating or rotary (rolling-piston or scroll) compressor. The expansion valve is usually thermal or electronic expansion valve. The refrigerant evaporating temperature is in the range of about 0 to about 10° C., while the condensing temperature is in the range of about 40 to about 70° C.

Operating Conditions:

[0629] 1. Condensing temperature=46° C., Corresponding outdoor ambient temperature=35° C. [0630] 2. Condenser sub-cooling=5.5° C. [0631] 3. Evaporating temperature=7° C., Corresponding indoor ambient temperature=26.7° C. [0632] 4. Evaporator Superheat=5.5° C. [0633] 5. Isentropic Efficiency=70% [0634] 6. Volumetric Efficiency=100% [0635] 7. Temperature Rise in Suction Line=5.5° C.

TABLE-US-00003 TABLE 3 Performance in Residential Air-Conditioning System (Cooling) Discharge Discharge Temperature Evaporator Pressure Pressure Difference Glide Refrigerant Capacity Efficiency ratio [kPa] [° C.] [° C.] R410A 100%  100% 100%  100%  0 0.08 1 96% 102% 99% 93% 5.9 1.36 2 95% 102% 99% 93% 5.8 1.46 3 95% 102% 99% 92% 5.6 1.57 4 94% 102% 99% 91% 5.4 1.82 [0636] Table 3 shows the thermodynamic performance of a residential air-conditioning system compared to R410A system. [0637] Compositions 1 to 4 show 95% or higher capacity (considering±2% uncertainty) and matched efficiency compared to R410A. This indicates the system performance is similar to R410A. [0638] Compositions 1 to 4 show 99% pressure ratio compared to R410A. This indicates the compressor efficiencies are similar to R410A, and no changes on R410A compressor are needed. [0639] Compositions 1 to 4 show discharge temperature rise within 10° C. compared to R410A. This indicates good compressor reliability and there is no risk of oil breakdown or motor burn-out. [0640] Compositions 1 to 4 show evaporator glide less than 2° C. This indicates the evaporator glide does not affect system performance.

Example 2. Residential Heat Pump System (Heating)

Description:

[0641] Residential heat pump systems are used to supply warm air (about 21° C.) to buildings in the winter. It is usually the same system as the residential air-conditioning system, however when the system is in the heat pump mode the refrigerant flow is reversed and the indoor coil becomes condenser and the outdoor coil becomes evaporator. Typical system types are split and mini-split heat pump system. The evaporator and condenser is usually round tube plate fin or microchannel heat exchanger. The compressor is usually reciprocating or rotary (rolling-piston or scroll) compressor. The expansion valve is usually thermal or electronic expansion valve. The refrigerant evaporating temperature is in the range of about −20 to about 3° C., while the condensing temperature is in the range of about 35 to about 50° C.

Operating Conditions:

[0642] 1. Condensing temperature=41° C., Corresponding indoor ambient temperature=21.1° C. [0643] 2. Condenser sub-cooling=5.5° C. [0644] 3. Evaporating temperature=0.5° C., Corresponding outdoor ambient temperature=8.3° C. [0645] 4. Evaporator Superheat=5.5° C. [0646] 5. Isentropic Efficiency=70% [0647] 6. Volumetric Efficiency=100% [0648] 7. Temperature Rise in Suction Line=5.5° C.

TABLE-US-00004 TABLE 4 Performance in Residential Heat pump System (Heating) Discharge Discharge Temperature Evaporator Heating Heating Pressure Pressure Difference Glide Refrigerant Capacity Efficiency ratio [kPa] [° C.] [° C.] R410A 100%  100% 100%  100%  0 0.08 1 95% 101% 99% 93% 6.3 1.32 2 95% 101% 99% 93% 6.2 1.42 3 94% 101% 99% 92% 6.0 1.53 4 93% 101% 99% 91% 5.7 1.78 [0649] Table 4 shows the thermodynamic performance of a residential heat pump system compared to R410A system. [0650] Compositions 1 to 4 show 95% capacity (considering ±2% uncertainty) and matched efficiency compared to R410A. This indicates the system performance is similar to R410A. [0651] Compositions 1 to 4 show 99% pressure ratio compared to R410A. This indicates the compressor efficiencies are similar to R410A, and no changes on R410A compressor are needed. [0652] Compositions 1 to 4 show discharge temperature rise within 10° C. compared to R410A. This indicates good compressor reliability and there is no risk of oil breakdown or motor burn-out. [0653] Compositions 1 to 4 show evaporator glide less than 2° C. This indicates the evaporator glide does not affect system performance.

Example 3. Commercial Air-Conditioning System—Chiller

Description:

[0654] Commercial air-conditioning systems (chillers) are used to supply chilled water (about 7° C.) to large buildings such as offices, hospitals, etc. Depending on the application, the chiller system may be running all year long. The chiller system may be air-cooled or water-cooled. The air-cooled chiller usually has a plate or shell-and-tube evaporator to supply chilled water, a reciprocating or scroll compressor, a round tube plate fin or microchannel condenser to exchange heat with ambient air, and a thermal or electronic expansion valve. The water-cooled system usually has a shell-and-tube evaporator to supply chilled water, a reciprocating or scroll compressor, a shell-and-tube condenser to exchange heat with water from cooling tower or lake, sea and other natural recourses, and a thermal or electronic expansion valve. The refrigerant evaporating temperature is in the range of about 0 to about 10° C., while the condensing temperature is in the range of about 40 to about 70° C.

Operating Conditions:

[0655] 1. Condensing temperature=46° C., Corresponding outdoor ambient temperature=35° C. [0656] 2. Condenser sub-cooling=5.5° C. [0657] 3. Evaporating temperature=4.5° C., Corresponding chilled leaving water temperature=7° C. [0658] 4. Evaporator Superheat=5.5° C. [0659] 5. Isentropic Efficiency=70% [0660] 6. Volumetric Efficiency=100% [0661] 7. Temperature Rise in Suction Line=2° C.

TABLE-US-00005 TABLE 5 Performance in Commercial Air-Conditioning System - Air-Cooled Chiller Discharge Discharge Temperature Evaporator Pressure Pressure Difference Glide Refrigerant Capacity Efficiency ratio [kPa] [° C.] [° C.] R410A 100%  100% 100%  100%  0 0.08 1 96% 102% 99% 93% 6.2 1.33 2 96% 102% 99% 93% 6.0 1.44 3 95% 102% 99% 92% 5.9 1.54 4 94% 102% 99% 91% 5.6 1.79 [0662] Table 5 shows the thermodynamic performance of a commercial air-cooled chiller system compared to R410A system. [0663] Compositions 1 to 4 show 95% or higher capacity (considering ±2% uncertainty) and matched efficiency compared to R410A. This indicates the system performance is similar to R410A. [0664] Compositions 1 to 4 show 99% pressure ratio compared to R410A. This indicates the compressor efficiencies are similar to R410A, and no changes on R410A compressor are needed. [0665] Compositions 1 to 4 show discharge temperature rise within 10° C. compared to R410A. This indicates good compressor reliability and there is no risk of oil breakdown or motor burn-out. [0666] Compositions 1 to 4 show evaporator glide less than 2° C. This indicates the evaporator glide does not affect system performance.

Example 4. Residential Air-to-Water Heat Pump Hydronic System

Description:

[0667] Residential air-to-water heat pump hydronic systems are used to supply hot water (about 50° C.) to buildings for floor heating or similar applications in the winter. The hydronic system usually has a round tube plate fin or microchannel evaporator to exchange heat with ambient air, a reciprocating or rotary compressor, a plate condenser to heat the water, and a thermal or electronic expansion valve. The refrigerant evaporating temperature is in the range of about −20 to about 3° C., while the condensing temperature is in the range of about 50 to about 90° C.

Operating Conditions:

[0668] 1. Condensing temperature=60° C., Corresponding indoor leaving water temperature=50° C. [0669] 2. Condenser sub-cooling=5.5° C. [0670] 3. Evaporating temperature=0.5° C., Corresponding outdoor ambient temperature=8.3° C. [0671] 4. Evaporator Superheat=5.5° C. [0672] 5. Isentropic Efficiency=70% [0673] 6. Volumetric Efficiency=100% [0674] 7. Temperature Rise in Suction Line=2° C.

TABLE-US-00006 TABLE 6 Performance in Residential Air-to-Water Heat Pump Hydronic System Discharge Discharge Temperature Evaporator Heating Heating Pressure Pressure Difference Glide Refrigerant Capacity Efficiency ratio [kPa] [° C.] [° C.] R410A 100%  100% 100%  100%  0 0.06 1 97% 102% 99% 93% 8.6 1.17 2 97% 102% 99% 92% 8.4 1.26 3 96% 102% 99% 92% 8.1 1.36 4 95% 102% 99% 91% 7.7 1.59 [0675] Table 6 shows the thermodynamic performance of a residential air-to-water heat pump hydronic system compared to R410A system. [0676] Compositions 1 to 4 show 95% or higher capacity and matched efficiency compared to R410A. This indicates the system performance is similar to R410A. [0677] Compositions 1 to 4 show 98%-99% pressure ratio compared to R410A. This indicates the compressor efficiencies are similar to R410A, and no changes on R410A compressor are needed. [0678] Compositions 1 to 4 show discharge temperature rise close to 10° C. compared to R410A. This indicates good compressor reliability and there is no risk of oil breakdown or motor burn-out. [0679] Compositions 1 to 4 show evaporator glide less than 2° C. This indicates the evaporator glide does not affect system performance.

Example 5. Medium Temperature Refrigeration System

Description:

[0680] Medium temperature refrigeration systems are used to chill food or beverages such as in a refrigerator and bottle cooler. The system usually has an air-to-refrigerant evaporator to chill the food or beverage, a reciprocating or rotary compressor, an air-to-refrigerant condenser to exchange heat with the ambient air, and a thermal or electronic expansion valve. The refrigerant evaporating temperature is in the range of about −12 to about 0° C., while the condensing temperature is in the range of about 40 to about 70° C.

Operating Conditions:

[0681] 1. Condensing temperature=45° C., Corresponding outdoor ambient temperature=35° C. [0682] 2. Condenser sub-cooling=5.5° C. [0683] 3. Evaporating temperature=−8° C., Corresponding box temperature=1.7° C. [0684] 4. Evaporator Superheat=5.5° C. [0685] 5. Isentropic Efficiency=65% [0686] 6. Volumetric Efficiency=100% [0687] 7. Temperature Rise in Suction Line=10° C.

TABLE-US-00007 TABLE 7 Performance in Medium Temperature Refrigeration System Discharge Discharge Temperature Evaporator Pressure Pressure Difference Glide Refrigerant Capacity Efficiency ratio [kPa] [° C.] [° C.] R410A 100%  100% 100%  100%  0 0.07 1 97% 102% 99% 93% 9.2 1.19 2 97% 102% 99% 93% 9.0 1.29 3 96% 102% 99% 92% 8.7 1.40 4 95% 102% 99% 91% 8.1 1.64 [0688] Table 7 shows the thermodynamic performance of a medium temperature refrigeration system compared to R410A system. [0689] Compositions 1 to 4 show 95% or higher capacity and matched efficiency compared to R410A. This indicates the system performance is similar to R410A. [0690] Compositions 1 to 4 show 98%-99% pressure ratio compared to R410A. This indicates the compressor efficiencies are similar to R410A, and no changes on R410A compressor are needed. [0691] Compositions 1 to 4 show discharge temperature rise close to 10° C. compared to R410A. This indicates good compressor reliability and there is no risk of oil breakdown or motor burn-out. [0692] Compositions 1 to 4 show evaporator glide less than 2° C. This indicates the evaporator glide does not affect system performance.

Example 6. Low Temperature Refrigeration System

Description:

[0693] Low temperature refrigeration systems are used to freeze food such as in an ice cream machine and freezer. The system usually has an air-to-refrigerant evaporator to chill the food or beverage, a reciprocating or rotary compressor, an air-to-refrigerant condenser to exchange heat with the ambient air, and a thermal or electronic expansion valve. The refrigerant evaporating temperature is in the range of about −40 to about −12° C., while the condensing temperature is in the range of about 40 to about 70° C.

Operating Conditions:

[0694] 1. Condensing temperature=55° C., Corresponding outdoor ambient temperature=35° C. [0695] 2. Condenser sub-cooling=5° C. [0696] 3. Evaporating temperature=−23° C., Corresponding box temperature=1.7° C. [0697] 4. Evaporator Superheat=5.5° C. [0698] 5. Isentropic Efficiency=60% [0699] 6. Volumetric Efficiency=100% [0700] 7. Temperature Rise in Suction Line=1° C.

TABLE-US-00008 TABLE 8 Performance in Low Temperature Refrigeration System Discharge Discharge Temperature Evaporator Pressure Pressure Difference Glide Refrigerant Capacity Efficiency ratio [kPa] [° C.] [° C.] R410A 100% 100% 100%  100%  0 0.05 1 100% 104% 98% 93% 14.7 0.94 2 100% 104% 98% 92% 14.2 1.03 3  99% 104% 98% 92% 13.7 1.12 4  98% 104% 98% 91% 12.8 1.35 [0701] Table 8 shows the thermodynamic performance of a low temperature refrigeration system compared to R410A system. [0702] Compositions 1 to 4 show 98% or higher capacity and matched efficiency compared to R410A. This indicates the system performance is similar to R410A. [0703] Compositions 1 to 4 show 97%-98% pressure ratio compared to R410A. This indicates the compressor efficiencies are similar to R410A, and no changes on R410A compressor are needed. [0704] Compositions 1 to 4 show evaporator glide less than 2° C. This indicates the evaporator glide does not affect system performance

Example 7. Stabilizers for Refrigerant/Lubricant Thermal Stability Example

Description:

[0705] The use of additives such as stabilizers ensures that the composition of the refrigerant (and lubricant) is effectively unchanged through the normal operation of the heat transfer equipment to which it is charged. Refrigerants and lubricants are typically tested against ASHRAE Standard 97—“Sealed Glass Tube Method to Test the Chemical Stability of Materials for Use within Refrigerant Systems” to simulate accelerated aging. After testing, the level of halides is used to judge refrigerant stability and the total acid number (TAN) is used to judge lubricant stability. In addition, the lubricant should be clear and colorless, the metals should be shiny (unchanged), and there should be no solids present.

[0706] The following experiment was carried out to show the effect of the addition of a stabilizer on a refrigerant/lubricant composition.

Sealed Tube Test Conditions:

[0707] 1. Sealed tubes contained 50% refrigerant and 50% lubricant by weight [0708] 2. Refrigerant was as set out in table 9 below [0709] 3. Lubricant was an ISO 68 POE [0710] 4. Refrigerant and Lubricant were degassed [0711] 5. Refrigerant contained <10 ppm moisture [0712] 6. Lubricant contained <30 ppm moisture [0713] 7. Sealed tubes contained coupons of steel, copper and aluminum [0714] 8. Sealed tubes were placed in oven at 175° C. for 14 days

TABLE-US-00009 TABLE 9 Composition of refrigerant HFC-32 HFC-125 CF3I HFO-1234yf Refrigerant (wt %) (wt %) (wt %) (wt %) 1 47% 12% 35% 6%

TABLE-US-00010 TABLE 10 Summary of desired outcome of experiment The aim of the experiment was to obtain the following results: Lubricant Metals Solids Halides TAN visual visual present? [ppm] [mgKOH/g] Clear, shiny no <300 <3.0 colorless

TABLE-US-00011 TABLE 11 Analysis of Refrigerant and Lubricant after Sealed Tube Testing Lubricant Metals Solids Halides TAN Comp. Additives visual visual present? [ppm] [mgKOH/g] 1 None Opaque, dull yes >400 >10 black 2 1.5% Farnesene + Clear, shiny no <300 <3.0 1.5% colorless Diphenylphosphite [0715] Table 11 shows the results of refrigerant and lubricant testing after sealed tube testing at 175° C. for 14 days [0716] Composition 1 shows that no thermal stability conditions were met with no stabilizers present [0717] Composition 2 shows that with 1.5 wt % each of Farnesene and Diphenylphosphite all test conditions were met. It indicates that this combination of refrigerant, lubricant and stabilizers are of similar thermal stability to other commercial refrigerants such as R410A.

[0718] Although the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention with departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims or any claims added later.