Low-GWP refrigerants for liquid chillers

Abstract

A refrigeration system is disclosed. The system includes a compressor, a condenser, an expansion device, and an evaporator, fluidically connected to form a refrigeration circuit. The system includes a refrigerant composition comprising an environmentally suitable chiller refrigerant having a 100-year direct global warming potential (GWP) of less than 150. The refrigerant composition includes a mixture comprising R-1336mzz-(Z) and R-1130-(E), wherein the amount of R-1336mzz-(Z) in the mixture is in a range of from or about 69% by weight to or about 81% by weight, and the amount of R-1130-(E) in the mixture is in a range of from or about 31% by weight to or about 19% by weight.

Description

[0001] This application is a divisional application of the invention patent with an application date of November 30, 2018, application number 201811456726.0, and invention name “Refrigerant with low global warming potential in liquid chillers”. Technical Field

[0002] The present disclosure relates generally to refrigeration systems. More particularly, the present disclosure relates to refrigeration systems, such as refrigeration, air conditioning, and / or heat pump systems, which may be incorporated into heating, ventilation, air conditioning, and refrigeration (HVACR) systems or units. Background Art

[0003] Refrigeration systems such as centrifugal chillers can operate with low-pressure refrigerants such as R-11, R-113, R-123 and multi-pressure refrigerants such as R-114 and R-245fa, for example, below atmospheric pressure at all times or under a set of operating or shutdown conditions. Summary of the Invention

[0004] Methods of using refrigerant compositions and / or methods of retrofitting chiller systems with refrigerant compositions are described.

[0005] The environmental impact of chiller refrigerants is a growing concern. For example, since 2011, the European Union has been phasing out refrigerants with a global warming potential (GWP) exceeding, for example, 150, from certain refrigeration systems. Environmentally suitable chiller refrigerants with appropriate properties (such as density, vapor pressure, heat of vaporization, and suitable chemistry) that meet safety and environmental impact requirements, such as those in the EU standards discussed above, can be used in chiller systems. Environmentally suitable chiller refrigerants are non-flammable or mildly flammable, non-ozone depleting, energy-efficient, low in toxicity, compatible with building materials, and chemically stable throughout the life of the equipment.

[0006] In one embodiment, the refrigerant composition of the present disclosure is used in a negative pressure liquid chiller.

[0007] In one embodiment, the refrigerant compositions of the present disclosure may be used as a replacement for R-123, R-11, and the like.

[0008] In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E).In one embodiment, the refrigerant composition is environmentally friendly, safe and energy-efficient.

[0009] In one embodiment, a method for filling a chiller system is disclosed. The method comprises removing existing refrigerant from the chiller system. Existing chiller refrigerant comprises relatively high global warming potential (GWP) or ozone depleting refrigerant and lubricant. The method comprises replacing all or part of the refrigerant of high GWP with a halogenated olefin composition. In one embodiment, the halogenated olefin composition comprises a blend of R-1336mzz-(Z) and R-1130-(E) or similar isomers. The major part (e.g., system hardware) of the chiller assembly remains and / or remains unchanged in the chiller system. In one embodiment, existing chiller refrigerant comprises R-123, R-11 etc.

[0010] In one embodiment, the proportion of R-1336mzz-(Z) can be from 69% or about 69% by weight to 81% or about 81% by weight. In one embodiment, the proportion of R-1130-(E) can be from 19% or about 19% by weight to 31% or about 31% by weight. For example, in one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 81% or about 81% by weight R-1336mzz-(Z) to 19% or about 19% by weight R-1130-(E). In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 69% or about 69% by weight R-1336mzz-(Z) to 31% or about 31% by weight R-1130-(E).

[0011] In one embodiment, the proportion of R-1336mzz-(Z) can be from 74% or about 74% by weight to 81% or about 81% by weight. In one embodiment, the proportion of R-1130-(E) can be from 19% or about 19% by weight to 26% or about 26% by weight. For example, in one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 81% or about 81% by weight R-1336mzz-(Z) to 19% or about 19% by weight R-1130-(E). In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 74% or about 74% by weight R-1336mzz-(Z) to 26% or about 26% by weight R-1130-(E).

[0012] In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 75% or about 75% by weight R-1336mzz-(Z) to 25% or about 25% by weight R-1130-(E). In such an embodiment, the refrigerant composition can have a vapor pressure similar to that of R-123 and / or R-11. In one embodiment, when retrofitting a chiller system operating with R-123 or R-11 refrigerant, limited or no hardware changes can be accomplished.

[0013] In one embodiment, replacing an existing refrigerant with a refrigerant composition described herein may result in adjusting impeller diameter or speed changes by gear changes or adding or adjusting variable frequency drives and / or motor sizes; adjusting improved evaporator or condenser tubes with more optimized tube reinforcement; switching to compatible lubricants including but not limited to polyesters, polyol esters, polyethylene ethers, alkyl benzenes, etc.; changing sealing materials (e.g., elastomers, liquid adhesives, etc.); adjusting orifice sizes to optimize refrigerant flow rates and seals between the evaporator and condenser; adjusting economizer sizes to allow for changes in refrigerant capacity storage and operation; replacing or changing the purification process to operate with the refrigerant composition; and / or adjusting, changing, or replacing controls to operate with the new refrigerant.

[0014] In one embodiment, a refrigeration system includes a compressor, a condenser, an expansion device, and an evaporator. The compressor, the condenser, the expansion device, and the evaporator are fluidly connected to form a refrigeration circuit. The chiller refrigerant includes a chiller refrigerant having a 100-year direct global warming potential (GWP) of less than 150. In one embodiment, the chiller refrigerant has a GWP of less than 10. In one embodiment, the chiller refrigerant has a GWP of less than 5. In one embodiment, the chiller refrigerant has a GWP of 2 or about 2.

[0015] In one embodiment, a method of performing a refrigeration cycle includes a refrigeration cycle that directs an environmentally suitable chiller refrigerant to a compressor, directs the environmentally suitable chiller refrigerant from the compressor to a condenser, directs the environmentally suitable chiller refrigerant from the condenser to an expander device, directs the environmentally suitable chiller refrigerant from the expansion device to an evaporator, and directs the environmentally suitable chiller refrigerant from the evaporator back to the compressor. The compressor, condenser, expansion device, and evaporator are fluidly connected to form a refrigeration circuit to perform the refrigeration cycle. The environmentally suitable chiller refrigerant has a 100-year direct global warming potential (GWP) of less than 150. In one embodiment, the chiller refrigerant has a GWP of less than 10. In one embodiment, the chiller refrigerant has a GWP of less than 5. In one embodiment, the chiller refrigerant has a GWP equal to or approximately 2. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Reference is made to the accompanying drawings which form a part of this disclosure, and which illustrate embodiments in which the systems and methods described herein may be practiced.

[0017] Figure 1 is a perspective view of an HVACR system for implementing the systems and methods described herein, according to one embodiment.

[0018] Figure 2 is a graph showing a relative comparison of the capacity and efficiency of the refrigerant compositions described in this specification according to one embodiment.

[0019] Like reference numerals refer to like parts throughout. DETAILED DESCRIPTION

[0020] The present disclosure relates generally to refrigeration systems. More particularly, the present disclosure relates to refrigeration systems, such as refrigeration, air conditioning, and / or heat pump systems, which may be incorporated into heating, ventilation, air conditioning, and refrigeration (HVACR) systems or units.

[0021] In existing HVACR units, such as chiller units, it can be difficult to replace the existing refrigerant in the chiller with a more environmentally friendly refrigerant composition without replacing the chiller unit. Therefore, it would be advantageous to have an environmentally friendly refrigerant composition that can be added to a state-of-the-art chiller. In one embodiment, replacing the existing refrigerant with an environmentally friendly refrigerant composition from the state of the art can be relatively less expensive than completely replacing the chiller.

[0022] In one embodiment, existing refrigerants used in the chiller may include, but are not limited to, R-123, R-11, and the like.

[0023] Negative pressure refrigerated liquid chillers include, for example, liquid water chillers that utilize a refrigerant operating at or below ambient pressure.

[0024] A refrigerant is considered environmentally friendly when its 100-year direct global warming potential (GWP) is less than 150 times that of carbon dioxide. GWP is a relative measure of the amount of heat trapped in the atmosphere by greenhouse gases, using carbon dioxide as a reference. GWP is calculated over a specific time interval, typically 20, 100, or 500 years. GWP is expressed as a factor of carbon dioxide (which has a standard GWP value of 1). The higher a refrigerant's GWP, the greater its potential to contribute to global climate change.

[0025] Figure 1FIG2 is a perspective view of an HVACR system 10 according to one embodiment, which can be implemented as a chiller or include a chiller for implementing the systems and methods described herein. The HVACR system 10 can include one or more additional features, which are not shown to simplify the drawing.

[0026] The illustrated HVACR system 10 includes a condenser 12, an evaporator 14, a multi-stage compressor 16 having a first-stage compressor 18, and a second-stage compressor 20 that can be driven by any suitable motor 22. According to one embodiment, it is understood that the compressor 16 can be a single-stage compressor. The HVACR system 10 can also include an economizer 24 that can be coaxial with the condenser 12. It should be understood that the HVACR system 10 can include one or more additional features, such as, but not limited to, one or more flow control devices, a lubricant separator, a radiator, a pump, etc.

[0027] A variable speed drive (VSD) system 32 includes a motor 22. The compressor 16 can be driven by the motor 22. The motor 22 can be located, for example, between the first-stage compressor 18, the second-stage compressor 20, and a VSD 34 including power electronics. Alternatively, the VSD 34 can be referred to as a variable frequency drive (VFD) 34. According to one embodiment, the motor 22 can include a direct-drive, variable-speed, hermetic motor. The speed of the motor 22 can be controlled by varying the frequency of the power provided to the motor 22 by the VFD 34. The VFD 34 can include, for example, a power converter including a line rectifier and a line current harmonic reducer, power circuitry, and control circuitry (such circuitry includes all communication and control logic, including electronic power switching circuitry). For example, the VFD 34 can increase and / or decrease the speed of the motor 22 by varying the frequency of the current provided to the motor 22 in response to signals received from a microprocessor integrated within the control panel 36. For example, the speed of the motor 22 can be varied to meet changing system requirements.

[0028] According to one embodiment, the operation of the first and second stage compressors 18, 20 and the HVACR system 10 can be controlled, for example, by a control panel 36 that is connected to sensors located within the HVACR system 10, which allows for reliable operation of the HVACR system 10. Other controls can be connected to the control panel 36, such as, but not limited to, compressor controls; system supervisory controls that can be connected to other controls to improve efficiency; soft motor starter controls; controls for adjusting guide vanes and / or controls to avoid system fluid surges; control circuits for the motor 22 and / or the VFD 34; and other contemplated sensor / control devices should be understood. It will be apparent that, for example, software related to the operation of the VFD 34 and other components of the HVACR system 10 can be provided.

[0029] It should be understood that the HVACR system 10 may include one or more additional components. For example, the HVACR system 10 may include a purifier, one or more acid filters, and the like.

[0030] The composition of the environmentally suitable chiller refrigerant adopted by the HVACR system 10 can include a halogenated olefin composition.The environmentally suitable chiller refrigerant can be a low-pressure refrigerant.A low-pressure refrigerant is a compound or blend having a vapor pressure less than, for example, about 14.7 pounds per square inch absolute (psia) at about 0°F.Because some components including the condenser 12 of the evaporator 14 and the HVACR system (under certain conditions) may operate at a pressure lower than atmospheric pressure, non-condensables such as air and moisture may leak into the chiller.These non-condensable elements enter the condenser 12 and are trapped in the condenser 12, resulting in an increase in condensing pressure and compressor power demand, thereby reducing chiller efficiency and cooling capacity.

[0031] In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E).In one embodiment, the refrigerant composition is environmentally friendly, safe and energy-efficient.

[0032] In one embodiment, the proportion of R-1336mzz-(Z) can be from 69% or about 69% by weight to 81% or about 81% by weight. In one embodiment, the proportion of R-1130-(E) can be from 19% or about 19% by weight to 31% or about 31% by weight. For example, in one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 81% or about 81% by weight R-1336mzz-(Z) to 19% or about 19% by weight R-1130-(E). In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 69% or about 69% by weight R-1336mzz-(Z) to 31% or about 31% by weight R-1130-(E).

[0033] In one embodiment, the proportion of R-1336mzz-(Z) can be from 74% or about 74% by weight to 81% or about 81% by weight. In one embodiment, the proportion of R-1130-(E) can be from 19% or about 19% by weight to 26% or about 26% by weight. For example, in one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 81% or about 81% by weight R-1336mzz-(Z) to 19% or about 19% by weight R-1130-(E). In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 74% or about 74% by weight R-1336mzz-(Z) to 26% or about 26% by weight R-1130-(E).

[0034] In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 75% or approximately 75% by weight R-1336mzz-(Z) to 25% or approximately 25% by weight R-1130-(E). In one embodiment, the blend of R-1336-(Z) and R-1130-(E) in a ratio of 75% or approximately 75% by weight R-1336mzz-(Z) to 25% or approximately 25% by weight R-1130-(E) can form an azeotropic mixture. In such an embodiment, the refrigerant composition can have a vapor pressure similar to that of R-123 and / or R-11. In one embodiment, when retrofitting a chiller system operating with R-123 or R-11 refrigerants, limited or no hardware changes can be achieved.

[0035] In one embodiment, the refrigerant composition is a blend of R-1336mzz-(Z) and R-1130-(E) in a ratio of 69.7% or approximately 69.7% by weight R-1336mzz-(Z) to 25.3% or approximately 25.3% by weight R-1130-(E). In such an embodiment, the refrigerant composition may be referred to as R-514A. It should be understood that the range of refrigerant compositions is relative to the component refrigerants in the refrigerant mixture. The refrigerant composition may be further combined with, for example, lubricants, additives, conditioning agents, etc.

[0036] In one embodiment, a suitable range of mixture component ratios can be determined based on, for example, temperature glide and / or deviation from the nominal composition. In one embodiment, a suitable range of mixture component ratios can be determined based on, for example, temperature glide, which causes fractionation of the blend between the liquid and vapor phases and results in reduced capacity, efficiency, or a combination of capacity and efficiency. In one embodiment, a suitable range of mixture component ratios can be determined by the flammability boundary or the ability of the mixing operation to accurately measure the weight, volume, or weight and volume of the components. In one embodiment, the temperature glide can be controlled to not exceed 1°F. In such an embodiment, the capacity can be controlled to within 5%. In one embodiment, the efficiency can be controlled to within 2%.

[0037] In one embodiment, replacing an existing refrigerant with a refrigerant composition as described herein may result in, for example, adjusting the impeller diameter or speed by gear changes or increasing or adjusting the variable frequency drive and / or motor size; adjusting the evaporator or condenser tubes with more optimized tube reinforcement; switching to a compatible lubricant including, but not limited to, polyesters, polyol esters, polyvinyl ethers, alkylbenzenes, etc.; changing the sealing material (e.g., elastomers, liquid adhesives, etc.); adjusting the orifice size to optimize the refrigerant flow rate and the seal between the evaporator and condenser; adjusting the economizer size to allow for changes in refrigerant capacity storage and operation; changing or changing the purge to operate with the refrigerant composition; and / or adjusting, changing, or replacing the control device to operate with the new refrigerant. In one embodiment, the impeller diameter may be increased or the impeller speed may be increased. In one embodiment, the orifice size may be reduced. In one embodiment, the economizer size may be increased.

[0038] In one embodiment, a method for filling a chiller system is disclosed. The method comprises removing existing refrigerant from the chiller system. Existing chiller refrigerant comprises a relatively high global warming potential (GWP) or a refrigerant and lubricant that reduces ozone. The method comprises replacing all or part of a high GWP refrigerant with a halogenated olefin composition. In one embodiment, the halogenated olefin composition comprises a blend of R-1336mzz-(Z) and R-1130-(E). The major part (e.g., system hardware) of the chiller assembly remains and / or remains unchanged in the chiller system. In one embodiment, existing chiller refrigerant comprises R-123, R-11 etc.

[0039] Figure 2 1 is a graph 100 showing a relative comparison of the capacity and efficiency of the refrigerant compositions described herein according to an embodiment. The illustrated embodiment shows a comparison of the capacity and coefficient of performance of a range of refrigerant compositions described herein and the existing refrigerant compositions R-123 and R-11. As shown in the graph, while the refrigerant composition described herein has a capacity of 1.00 and a coefficient of performance of 1.00, the capacity and coefficient of performance of the existing refrigerants vary within a similar range. Figure 2 The refrigerant compositions described herein are shown to provide an alternative with similar characteristics to existing refrigerants.

[0040] aspect:

[0041] Any one of aspects 1-4 may be combined with any one of aspects 5-11 or 12-23. Any one of aspects 5-11 may be combined with any one of aspects 12-23.

[0042] Aspect 1. A refrigerant composition comprising:

[0043] A mixture comprising R-1336mzz-(Z) and R-1130-(E),

[0044] wherein the amount of R-1336mzz-(Z) in the mixture is in the range of 69 wt % or about 69 wt % to 81 wt % or about 81 wt %, and the amount of R-1130-(E) in the mixture is in the range of 31 wt % or about 31 wt % to 19 wt % or about 19 wt %, and

[0045] wherein the refrigerant composition has a 100-year direct global warming potential (GWP) of less than 150.

[0046] Aspect 2. The refrigerant composition of aspect 1, wherein the amount of R-1336mzz-(Z) in the mixture is in the range of 69 weight % or about 69 weight % to 76 weight % or about 76 weight %, and the amount of R-1130-(E) in the mixture is in the range of 31 weight % or about 31 weight % to 24 weight % or about 24 weight %.

[0047] Aspect 3. The refrigerant composition according to aspect 1, wherein the amount of R-1336mzz-(Z) in the mixture is 75% or about 75% by weight, and the amount of R-1130-(E) in the mixture is 25% or about 25% by weight.

[0048] Aspect 4. The refrigerant composition according to any one of aspects 1 to 3, wherein the refrigerant composition is a low-pressure refrigerant for a low-pressure chiller system.

[0049] Aspect 5. A refrigeration system comprising:

[0050] A compressor, a condenser, an expansion device, and an evaporator fluidly connected to form a refrigeration circuit; and

[0051] A refrigerant composition comprising an environmentally suitable chiller refrigerant having a 100-year direct global warming potential (GWP) of less than 150, the refrigerant composition comprising a blend comprising R-1336mzz-(Z) and R-1130-(E), wherein the amount of R-1336mzz-(Z) in the blend is in the range of 69 weight percent or about 69 weight percent to 81 weight percent or about 81 weight percent, and the amount of R-1130-(E) in the blend is in the range of 31 weight percent or about 31 weight percent to 19 weight percent or about 19 weight percent.

[0052] Aspect 6. The refrigeration system of aspect 5, wherein the amount of R-1336mzz-(Z) in the mixture is in the range of 69 weight % or about 69 weight % to 76 weight % or about 76 weight %, and the amount of R-1130-(E) in the mixture is in the range of from 31 weight % or about 31 weight % to 24 weight % or about 24 weight %.

[0053] Aspect 7. The refrigeration system according to aspect 5, wherein the amount of R-1336mzz-(Z) in the mixture is 75% or about 75% by weight, and the amount of R-1130-(E) in the mixture is 25% or about 25% by weight.

[0054] Aspect 8. The refrigeration system according to any one of aspects 5 to 7, wherein the refrigerant composition is a low-pressure refrigerant for a low-pressure chiller system.

[0055] Aspect 9. The refrigeration system according to any one of aspects 5 to 8, further comprising a purifier.

[0056] Aspect 10. The refrigeration system according to any one of aspects 5-9, wherein the environmentally suitable chiller refrigerant has a Global Warranty Plumbing (GWP) of less than 10.

[0057] Aspect 11. The refrigeration system according to any one or any one of aspects 5-10, wherein the environmentally suitable chiller refrigerant has a GWP equal to or about 2.

[0058] Aspect 12. A method for filling a chiller system, comprising:

[0059] Remove existing refrigerant from the chiller system;

[0060] The existing refrigerant is replaced with an environmentally friendly refrigerant composition, which includes a mixture of R-1336mzz-(Z) and R-1130-(E).

[0061] Aspect 13. The method of aspect 12, wherein the existing chiller refrigerant has a 100-year direct global warming potential (GWP) of at least 150 or is an ozone-depleting refrigerant and lubricant.

[0062] Aspect 14. The method according to aspect 12, wherein the existing chiller refrigerant comprises at least one of R-123 and R-11.

[0063] Aspect 15. The method according to any one of aspects 12-14, further comprising retaining existing chiller hardware when replacing the existing refrigerant.

[0064] Aspect 16. The method according to any one of aspects 12-15, wherein the environmentally friendly chiller refrigerant has a GWP of less than 150.

[0065] Aspect 17. A method according to aspect 16, wherein the amount of R-1336mzz-(Z) in the mixture is in a range from 69% or about 69% by weight to 81% or about 81% by weight, and the amount of R-1130-(E) in the mixture is in a range from 31% or about 31% by weight to 19% or about 19% by weight.

[0066] Aspect 18. A method according to aspect 16, wherein the amount of R-1336mzz-(Z) in the mixture is in a range from 69% or about 69% by weight to 76% or about 76% by weight, and the amount of R-1130-(E) in the mixture is in a range from 31% or about 31% by weight to 24% or about 24% by weight.

[0067] Aspect 19. The method of aspect 16, wherein the amount of R-1336mzz-(Z) in the mixture is 75% or about 75% by weight, and the amount of R-1130-(E) in the mixture is 25% or about 25% by weight.

[0068] Aspect 20. The method of any one of aspects 12-19, wherein the refrigerant composition is a low-pressure refrigerant and the chiller system is a low-pressure chiller system.

[0069] Aspect 21. The method according to any one of aspects 12-20, wherein the environmentally friendly refrigerant composition has a GWP of less than 10.

[0070] Aspect 22. The method according to any one of aspects 12-21, wherein the environmentally friendly chiller refrigerant has a Global Weakness Plot (GWP) of 2 or about 2.

[0071] Aspect 23. The method according to any one of aspects 12-21, further comprising one or more of the following:

[0072] Adjusting impeller diameter or speed changes by gear changes or adding or adjusting the variable frequency drive and / or motor size; adjusting an improved evaporator or condenser tubes with more optimized tube reinforcement; switching to a compatible lubricant including one of polyester, polyol ester, polyethylene ether, and alkylbenzene; changing the sealing material; adjusting the orifice size to optimize the refrigerant flow rate and the seal between the evaporator and condenser; adjusting the size of the economizer to allow for changes in refrigerant capacity storage and operation; replacing or changing the purifier to operate with an environmentally friendly refrigerant composition; and adjusting, changing, or replacing the control device to operate with an environmentally friendly refrigerant composition.

[0073] The terms used in this specification are intended to describe specific embodiments and are not intended to be limiting. Unless expressly stated otherwise, the terms "a," "an," and "the" include plural forms. When the terms "include" and / or "comprise" are used, they indicate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components.

[0074] With respect to the foregoing description, it should be understood that changes may be made in detail, particularly in the materials of construction employed and the shapes, sizes, and arrangements of components, without departing from the scope of the present disclosure. The term "embodiment" may refer to, but does not necessarily refer to, the same embodiment. The embodiments and disclosure are merely exemplary. Other and further embodiments may be devised without departing from the basic scope of the present invention, the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. A method for improving a chiller system, characterized in that: The chiller system includes a compressor, a condenser, an expansion device, and an evaporator fluidly connected to form a refrigeration circuit, and the method includes: removing existing refrigerant from said refrigeration circuit; adding a new refrigerant composition to the refrigeration circuit, the new refrigerant composition comprising a mixture of R-1336mzz-(Z) and R-1130-(E); and modifying one or more components of the chiller system to operate with the new refrigerant composition, wherein modifying one or more components of the chiller system consists of at least one member selected from the group consisting of: Modify the purifier of the refrigerant circuit, Modifying the size of economizers in the refrigerant circuit, and An orifice size in the refrigerant circuit is modified to change the refrigerant flow between the evaporator and the condenser.

2. The method according to claim 1, characterized in that Modifying one or more components of the chiller system includes modifying the purifier in the refrigerant circuit.

3. The method according to claim 2, characterized in that Modifying the purifier in the refrigerant circuit includes replacing an existing purifier in the refrigerant circuit.

4. The method according to claim 1, wherein The refrigerant circuit includes the economizer, and Modifying one or more components of the chiller system includes modifying the size of the economizer.

5. The method according to claim 4, characterized in that Modifying the size of the economizer includes increasing the size of the economizer.

6. The method according to claim 1, characterized in that Modifying one or more components of the chiller system includes modifying the orifice size.

7. The method according to claim 6, characterized in that Modifying the orifice size includes reducing an orifice size to reduce the refrigerant flow between the evaporator and the condenser.

8. The method according to claim 1, characterized in that The new refrigerant composition has a vapor pressure of less than 14.7 psig at 0°F, and the chiller system operates as a negative pressure chiller system using the new refrigerant composition.

9. The method according to claim 1, characterized in that The chiller system with the existing refrigerant is configured to operate at least temporarily at subatmospheric pressure.

10. The method according to claim 1, characterized in that The existing refrigerant includes at least one of R-11, R-113, R-114, R-123 and R245fa.

11. The method according to claim 1, wherein The amount of R-1336mzz-(Z) in the mixture ranges from 69% to 81% by weight, and the amount of R-1130-(E) in the mixture ranges from 31% to 19% by weight.

12. The method according to claim 11, characterized in that The amount of R-1336mzz-(Z) in the mixture ranges from 69 wt% to 76 wt%, and the amount of R-1130-(E) in the mixture ranges from 31 wt% to 24 wt%.

13. The method according to claim 11, characterized in that The amount of R-1336mzz-(Z) in the mixture was 75% by weight, and the amount of R-1130-(E) in the mixture was 25% by weight.

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