Climate Control Systems For Use With High Glide Working Fluids And Methods For Detecting A Concentration of Refrigerant In The Working Fluid

Abstract

A method for determining the composition of a mixed working fluid in a temperature control system comprises the steps of: detecting the characteristics of the working fluid flowing through a fluid conduit at a specific location in the fluid conduit using a sensor; calculating a first concentration of a first refrigerant in the mixed working fluid at that location; and calculating a second concentration of a second refrigerant in the mixed working fluid at that location. The calculation of the first concentration of the first refrigerant is based on the detected characteristics and stored information. The stored information includes a first stored value of the first refrigerant and a second stored value of the second refrigerant. The calculation of the second concentration of the second refrigerant is also based on the detected characteristics and stored information. This calculation is based solely on the detected characteristics and stored information.

Description

Technology Field

[0001] The present disclosure relates to a climate control system using a working fluid comprising a refrigerant mixture exhibiting a high temperature glide, and a method for detecting the concentration of each refrigerant in said refrigerant mixture.

[0003] Cross-reference regarding related applications

[0004] This application is a divisional application of U.S. Patent Application No. 19 / 078,684 filed on March 13, 2025, the entire contents of said application are incorporated herein by reference. Background Technology

[0005] This section is intended to provide background information related to the present disclosure and does not necessarily imply prior art.

[0006] Conventional thermodynamic temperature control systems, such as heat pump systems, refrigeration systems, or air conditioning systems, may include a fluid circuit. The fluid circuit generally includes a first heat exchanger (e.g., a condenser that causes a phase change of the refrigerant from a gas / vapor phase to a liquid phase) located outside or outdoors of the environment to be cooled, a second heat exchanger (e.g., an evaporator that causes a phase change of the refrigerant from a liquid phase to a gas / vapor phase) located inside or indoors of the environment to be cooled, an expansion device disposed between the first and second heat exchangers, and a compressor that operates via a vapor compression cycle (VCC) and circulates the gas / vapor refrigerant (and optionally lubricating oil) between the first and second heat exchangers (e.g., a condenser and an evaporator). The compressor is generally a mechanical compressor that performs the function of pressurizing the refrigerant, and the pressurized refrigerant can transfer heat to the system or remove heat from the system while undergoing condensation and evaporation processes as it circulates within the system.

[0007] The efficient and reliable operation of heating and cooling temperature control systems can help reduce energy consumption and potential greenhouse gas emissions associated with the use and leakage of specific refrigerants. The heating, ventilation, air conditioning, and refrigeration (HVAC / R) industry has continuously sought Grade A1 (non-toxic and non-flammable) refrigerants and blends containing these Grade A1 refrigerants, which offer high cooling capacity per displacement while protecting the safety of equipment operators and users, and enabling low-cost compression and piping by avoiding supercritical operation and sub-atmospheric pressure. Therefore, it is desirable to use temperature control systems capable of successfully utilizing eco-friendly refrigerants with a low Global Warming Potential (GWP).

[0008] Some eco-friendly refrigerants, such as high-glide refrigerants, may be in the form of a mixture of two or more refrigerants having different characteristics, such as different boiling points, critical points, and densities. Therefore, the composition (i.e., the concentration of each refrigerant) of the working fluid containing the high-glide refrigerant may change as it passes through the temperature control system. To improve the efficiency of the temperature control system, it is desirable to determine the composition of the working fluid while the system is operating. means of solving the problem

[0009] This section is intended to provide a general overview of the present disclosure and does not comprehensively disclose the full scope or all features thereof.

[0010] The present disclosure provides a method for determining the composition of a mixed working fluid in a temperature control system in various aspects. The method comprises the step of detecting the characteristics of a working fluid flowing through a fluid conduit at a specific location of the fluid conduit using a sensor. Additionally, the method further comprises the step of determining the composition of the working fluid by calculating a first concentration of a first refrigerant of the mixed working fluid at said location and calculating a second concentration of a second refrigerant of the mixed working fluid at said location. Calculating the first concentration of the first refrigerant is based on said characteristics and stored information. said stored information includes a first stored value for said first refrigerant and a second stored value for said second refrigerant. Calculating the second concentration of said second refrigerant is based on said characteristics and said stored information. said calculation is performed based solely on said characteristics and said stored information.

[0011] In one aspect, the mixed working fluid is a high glide refrigerant mixture.

[0012] In one aspect, the sensor includes one of a temperature sensor, a pressure sensor, a capacitance sensor, a flow sensor, and an acoustic velocity sensor.

[0013] In one aspect, the sensor is positioned outside the fluid conduit and configured to be in fluidic communication with the mixed working fluid.

[0014] In one aspect, the sensor is configured to be disposed inside the fluid conduit and fluidically communicate with the mixed working fluid.

[0015] In one aspect, the sensor is placed inside a component of the temperature control system. The component includes one of a separator, a compressor, a liquid pump, a valve, and a heat exchanger.

[0016] In one aspect, the first refrigerant has a first density, and the second refrigerant has a second density different from the first density. The first stored value is the first density, and the second stored value is the second density. The sensor is a pressure sensor configured to detect the pressure of the mixed working fluid at the location within the fluid conduit. The characteristic includes the pressure.

[0017] In one aspect, the composition determination step comprises calculating the first concentration based on the pressure, the first density, and the second density. The composition determination step further comprises calculating the second concentration based on the pressure, the first density, and the second density.

[0018] In one aspect, prior to the characteristic detection step, the method further includes a step of heating a portion of the mixed working fluid.

[0019] In one aspect, the first refrigerant has a first dielectric constant, and the second refrigerant has a second dielectric constant different from the first dielectric constant. The first stored value is the first dielectric constant, and the second stored value is the second dielectric constant. The sensor is a capacitance sensor configured to detect the capacitance of the working fluid in the fluid conduit, and the characteristic is the capacitance.

[0020] In one aspect, the composition determination step comprises calculating the first concentration based on the capacitance, the first dielectric constant, and the second dielectric constant. The composition determination step further comprises calculating the second concentration based on the capacitance, the first dielectric constant, and the second dielectric constant.

[0021] In one aspect, the first refrigerant has a first liquid acoustic velocity, and the second refrigerant has a second liquid acoustic velocity different from the first liquid acoustic velocity. The first stored value is the first liquid acoustic velocity, and the second stored value is the second liquid acoustic velocity. The sensor is a liquid acoustic velocity sensor configured to detect the acoustic velocity of the working fluid in the fluid conduit, and the characteristic is the acoustic velocity.

[0022] In one aspect, the sensor includes an acoustic transmitter and an acoustic receiver located downstream of the acoustic transmitter.

[0023] In one aspect, the composition determination step comprises calculating the first concentration based on the acoustic velocity of the working fluid, the first liquid acoustic velocity, and the second liquid acoustic velocity. The composition determination step further comprises calculating the second concentration based on the acoustic velocity, the first liquid acoustic velocity, and the second liquid acoustic velocity.

[0024] In one aspect, the method further includes the step of changing the operation of a component of the temperature control system based on the composition.

[0025] In one aspect, the sensor is positioned between a liquid-to-suction heat exchanger and an expansion valve.

[0026] In one aspect, after the composition determination step, the method further comprises the step of adding a certain amount of (i) the first refrigerant, (ii) the second refrigerant, or (i) the first refrigerant and (ii) the second refrigerant, to the temperature control system based on the composition.

[0027] The present invention provides a method for determining the composition of a mixed working fluid in a temperature control system in various aspects. The method includes the step of detecting the pressure of the mixed working fluid within the separator using a first sensor installed inside the separator. The separator is configured to separate a first portion of the mixed working fluid into a first phase and a second portion of the mixed working fluid into a second phase. Additionally, the method includes the step of detecting the temperature of the mixed working fluid within the separator using a second sensor installed inside the separator. The method further includes the step of detecting a first flow rate of the first portion of the working fluid. The first flow rate is detected using a third sensor connected to the compressor when the first portion of the working fluid passes through the compressor. The compressor is located downstream of the separator. The method further includes the step of detecting a second flow rate of the second portion of the working fluid. The second flow rate is detected using a fourth sensor connected to the pump when the second portion of the working fluid passes through the pump. The pump is located downstream of the separator. The above method further includes the step of determining the composition of the mixed working fluid by calculating the concentration of the first refrigerant based on the pressure, the temperature, the first flow rate, and the second flow rate. The composition determination step further includes the step of calculating the concentration of the second refrigerant based on the pressure, the temperature, the first flow rate, and the second flow rate.

[0028] In one aspect, the method further includes the step of changing the operation of a component of a temperature control system based on the composition.

[0029] In one aspect, the method further comprises the step of adding a certain amount of (i) the first refrigerant, (ii) the second refrigerant, or (i) the first refrigerant and (ii) the second refrigerant, based on the composition, to the temperature control system.

[0030] Additional fields of application will become clear from the descriptions provided in this specification. The descriptions and specific examples presented in this section are for illustrative purposes only and are not intended to limit the scope of this disclosure. Brief explanation of the drawing

[0031] The drawings described herein are for illustrating selected embodiments only and do not represent all possible embodiments or limit the scope of the disclosure. FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a temperature control system for circulating a working fluid comprising a mixed refrigerant exhibiting a high glide, according to various aspects of the present disclosure. FIG. 2 is a pressure-enthalpy phase diagram illustrating the operating principle of the temperature control system of FIG. 1 according to a specific aspect of the present disclosure. FIG. 3 is a block diagram illustrating a control module of the system of FIG. 1 according to various aspects of the present disclosure. FIG. 4 is a flowchart illustrating an algorithm of a method for determining the composition of a mixed working fluid in a temperature control system according to various aspects of the present disclosure. FIG. 5 is an exemplary embodiment of a sensor for detecting the characteristics of a mixed working fluid according to a specific aspect of the present disclosure. FIG. 6 is an exemplary embodiment of another sensor for detecting characteristics of a mixed working fluid according to a specific aspect of the present disclosure. FIG. 7 is an exemplary embodiment of another sensor for detecting characteristics of a mixed working fluid according to a specific aspect of the present disclosure. FIG. 8 is an exemplary embodiment illustrating a plurality of sensors for detecting characteristics of a mixed working fluid, a first portion of the working fluid, and a second portion of the working fluid according to a specific aspect of the present disclosure. FIG. 9 is a schematic diagram illustrating another exemplary embodiment of a temperature control system comprising a liquid pump that circulates a working fluid comprising a mixed refrigerant having a high temperature gradient, according to various aspects of the present disclosure. FIG. 10 is a schematic diagram illustrating another exemplary embodiment of a temperature control system according to various aspects of the present disclosure, comprising a liquid pump and a pair of four-way valves, circulating a working fluid comprising a mixed refrigerant having a high temperature gradient. FIG. 11 is a schematic diagram illustrating another exemplary embodiment of a temperature control system according to various aspects of the present disclosure, comprising a liquid pump, an accumulator, a receiver, and at least one expansion valve, which circulates a working fluid comprising a mixed refrigerant having a high temperature gradient. In multiple drawings, the same reference numeral indicates a corresponding part. Specific details for implementing the invention

[0032] Exemplary embodiments are provided to ensure that the present disclosure is fully understood and to fully convey the scope of the disclosure to a person skilled in the art. Various specific details, such as specific compositions, components, apparatuses, and methods, are presented to ensure a full understanding of the exemplary embodiments of the present disclosure. It is evident to a person skilled in the art that specific details are not necessarily required to be used, that the exemplary embodiments may be implemented in various forms, and that such details or forms should not be interpreted as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, apparatus structures, and technologies may not be described in detail.

[0033] The terms used herein are for the purpose of describing specific exemplary embodiments and are not intended to limit the scope. Unless singular or plural expressions are absent or singular expressions are specified, they may include both singular and plural forms. Terms such as “comprising,” “comprising,” “comprising,” and “having” are inclusive and indicate the presence of the specified features, elements, compositions, steps, integers, operations, and / or components, and do not exclude the presence of one or more additional features, integers, steps, operations, elements, components, and / or groups thereof. The non-limiting term “comprising” is used to describe and claim the various embodiments described herein, but in certain aspects, it may be understood in a more restrictive sense, such as “composed of” or “essentially composed of.” Accordingly, any embodiment in this specification referring to a composition, material, component, element, feature, integer, step, operation and / or process step, etc., in this regard includes only the said composition, or includes an embodiment that includes additional components in addition to the said composition that do not substantially affect the basic and novel properties. In other embodiments, where "composed of," no additional composition, material, component, element, feature, integer, step, operation and / or process step is included, but where "essentially composed of," additional composition, material, component, element, feature, integer, step, operation and / or process step that substantially affects the basic and novel properties is excluded, but composition, material, component, element, feature, integer, step, operation and / or process step that does not affect may be included.

[0034] All method steps, processes, and operations described herein should not be construed as being required to be performed in the specific order described or illustrated, except where the order of execution is specifically specified. It should also be understood that additional or alternative steps may be applied unless otherwise noted.

[0035] Where one component, element, or layer is referred to as being "on," "engaged," "connected," or "combined" with another component, element, or layer, it may be directly on, engaged with, connected to, or combined with the other component, element, or layer, or an intermediate element or layer may exist. Conversely, where one element is referred to as being "directly on," "directly engaged," "directly connected," or "directly combined" with another element or layer, there may be no intermediate element or layer. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" vs. "directly between," "adjacently" vs. "directly adjacently," etc.). As used in this application specification, the term "and / or" includes any combination of one or more of the items enumerated in relation thereto and all combinations thereof.

[0036] In this application specification, terms such as first, second, third, etc., may be used to describe various steps, elements, components, regions, layers, and / or sections, but unless otherwise stated, such steps, elements, components, regions, layers, and / or sections should not be limited by such terms. Such terms may be used solely to distinguish one step, element, component, region, layer, or section from another step, element, component, region, layer, or section. Terms such as "first," "second," and other numbered terms do not imply a sequence or order unless explicitly indicated by the context. Therefore, the first step, first element, first component, first region, first layer, or first section discussed below may refer to a second step, second element, second component, second region, second layer, or second section without departing from the teachings of the exemplary embodiments.

[0037] Spatial and temporal relative terms such as "previous," "after," "inner," "outer," "under," "below," "lower side," "above," and "upper side" may be used for convenience to describe the relative relationships between elements or features as illustrated in the drawings. Such temporal or spatial terms may include other orientations of the device or system during use or operation in addition to the orientations illustrated in the drawings.

[0038] Throughout this disclosure, numerical values ​​include not only values ​​that exactly match the specified values, but also approximations or limits of a range that include slight deviations from the specified values. Except for the examples provided at the end of the detailed description, numerical values ​​of all parameters (e.g., quantities or conditions) in this specification and the appended claims should always be understood as being modified by the term “about,” regardless of whether the term “about” actually appears before the numerical value. “About” indicates that the specified numerical value allows for a slight error (a value that is somewhat close to the accuracy, approximately or reasonably close, nearly). If the error expressed as “about” is not understood in this general sense in the art, “about” as used in this specification indicates at least the variation that may occur in the general method of measuring and using the parameter. For example, “about” may include a variation of 5% or less, optionally 4% or less, 3% or less, 2% or less, 1% or less, 0.5% or less, and optionally 0.1% or less in certain aspects.

[0039] Additionally, any reference to a range in this disclosure includes endpoints and sub-ranges, encompassing all values ​​within the entire range and more granular ranges.

[0040] Exemplary embodiments will be described in more detail below with reference to the attached drawings.

[0041] High Glide Refrigerant Blends

[0042] In various aspects of the present disclosure, the present disclosure relates to a climate control system that facilitates the use of a working fluid comprising a mixed refrigerant and a method for operating said system. The refrigerant mixture may include an environmentally friendly refrigerant (e.g., including one or more A1 refrigerants) and may exhibit a high and / or extreme glide during operation. A climate control system equipped with a refrigerant exhibiting a high and / or extreme glide is capable of capacity modulation. In specific aspects of the present disclosure, the working fluid composition for a refrigeration system for a heat transfer device, such as a compressor machine, for example, may include a refrigerant mixture comprising at least two or more refrigerants. The working fluid may be modified by adding a lubricant during operation, said lubricant having a selective affinity for at least one refrigerant and may change the concentration of the refrigerant mixture circulating within the system. In the context of the present disclosure, the working fluid comprises at least two different refrigerants, and these may form a mixture of refrigerant compositions (also referred to as "mixed refrigerant").

[0043] Some refrigerant mixtures have traditionally been considered a problem to be avoided in temperature control systems due to fractionation and high temperature gradients. Many refrigerant mixtures exhibit temperature gradients when undergoing phase changes in the evaporator and condenser. As previously mentioned, in the evaporator, the refrigerant undergoes evaporation—that is, a phase change from liquid to vapor. In the condenser, the refrigerant undergoes condensation—that is, a phase change from vapor to liquid. The reason refrigerant mixtures exhibit temperature gradients is the presence of multiple refrigerant molecules with different characteristics. During the phase changes (evaporation and condensation) of these refrigerant mixtures, a phenomenon is observed in which the composition of the mixture changes due to the preferential evaporation or condensation of more or less volatile refrigerant components (also known as high-pressure and low-pressure refrigerants); this is called blend fractionation.

[0044] Therefore, the total temperature gradient of a refrigerant mixture can be defined as the difference between the saturated vapor temperature and the saturated liquid temperature at constant pressure. In other words, the temperature gradient can be considered as the temperature difference between the starting temperature and the ending temperature of the refrigerant phase change within the system at constant pressure.

[0045] In certain aspects of the present technology, a working fluid is used that is intentionally selected to have a high temperature gradient refrigerant mixture, contrary to intuition. In certain aspects, the refrigerant mixture may comprise a first refrigerant and a second refrigerant. The first refrigerant and the second refrigerant may be selected for various characteristics such as their respective normal boiling point, glide efficiency, Global Warming Potential, environmental impact (e.g., impact of polyfluoroalkyl substances (PFAS)), capacity, pressure, and safety. For example, the present disclosure may use a refrigerant mixture comprising at least one refrigerant with a low Global Warming Potential, such as an ASHRAE Class A1 or A2L refrigerant.

[0046] In certain aspects, the first refrigerant may be a refrigerant with a relatively low normal boiling point (which may also be referred to as a 'high-pressure refrigerant'), and the second refrigerant may be a refrigerant with a relatively high normal boiling point (which may also be referred to as a 'low-pressure refrigerant'). In certain aspects, the first refrigerant may have a first (low) boiling point, which ranges from about -270°C or higher (e.g., above -250°C, above -225°C, above -200°C, above -175°C, above -150°C, above -125°C, above -100°C, above -75°C, above -50°C, above -25°C, above 0°C) to about 8°C or lower (e.g., below 0°C, below -25°C, below -50°C, below -75°C, below -100°C, below -150°C, below -175°C, below -200°C, below -225°C, below -250°C). Thus, the low boiling point refrigerant may have a range of about -267°C for hydrogen to about 7.5°C for R1336 mzz(E). In certain aspects, the second refrigerant may have a second (high) boiling point, which ranges from about -55°C or higher (e.g., above -50°C, above -25°C, above -0°C, above 25°C, above 50°C, above 750°C) to about 100°C or lower (e.g., below 75°C, below 50°C, below 25°C, below 0°C, below -25°C, below -50°C). For example, a high boiling point refrigerant may range from about -52°C for R32 to 100°C for water. As a skilled technician would know, refrigerant components are selected to create a mixture that meets the system objectives of the application. Different mixtures may be selected depending on cryogenic applications, low-temperature refrigeration, medium-temperature refrigeration, air conditioning, and various process cooling applications.

[0047] Accordingly, the working fluid comprises a first refrigerant and a second refrigerant, and the normal boiling point difference between the two refrigerants (ΔT = boiling point of the first refrigerant (BP1) - boiling point of the second refrigerant (BP2)) may be greater than about 10°F (about 5°C), greater than about 15°F (about 8°C), greater than about 20°F (about 11°C), greater than about 25°F (about 14°C), or greater than about 30°F (about 17°C) at atmospheric pressure. In certain aspects, the normal boiling point difference between the first refrigerant and the second refrigerant may be greater than about 50°F (about 28°C), greater than 75°F (about 42°C), greater than about 100°F (about 55°C), greater than about 125°F (about 69°C), or greater than about 150°F (about 83°C) at atmospheric pressure.

[0048] Climate Control System

[0049] In certain aspects of the present disclosure, thermodynamic temperature control systems configured to use high temperature gradient refrigerant mixtures, such as heat pump systems, refrigeration systems, and / or air conditioning systems, are considered. In various aspects of the present disclosure, temperature control systems used in various refrigeration and thermal energy transfer applications may be applied to industrial or commercial air conditioning and refrigeration units, and may be used, for example, in factories, office buildings, apartments, warehouses, ice rinks, or for retail sales.

[0050] In various aspects of the present disclosure, the amount of each refrigerant present in each phase of a high temperature gradient refrigerant mixture (hereinafter also referred to as the “refrigerant mixture” or “working fluid”) may vary at different points in a thermodynamic control system (hereinafter also referred to as the “refrigerant system” or “temperature control system”) and may be determined according to specific system requirements. Specifically, the amount or concentration of each of the first refrigerant and the second refrigerant in the refrigerant mixture (i.e., the relative ratio of the first refrigerant and the second refrigerant in the refrigerant mixture) may change over time within the refrigeration system. In various aspects of the present disclosure, the temperature control system may include one or more controllers capable of calculating and / or determining the composition of the refrigerant mixture using data from sensors and / or detection systems. In other words, one or more controllers may determine the amount of each refrigerant in the refrigerant mixture at different points within the system. Additionally, the controller may control the operation of the temperature control system based on the determined refrigerant mixture composition at a predetermined location within the temperature control system. A temperature control system including a controller, sensors, and / or detection systems can have higher efficiency and better adjustability compared to a temperature control system without a controller, sensors, and / or detection systems that provide information about the refrigerant composition.

[0051] For example, FIG. 1 shows an example schematic diagram of a simplified temperature control system (20) (e.g., a refrigeration system). The temperature control system (20) processes and circulates a working fluid or mixed refrigerant comprising a first refrigerant (A) and a second refrigerant (B) that exhibit a high temperature gradient. The capacity of the temperature control system (20) can be controlled by changing the relative ratio of the first refrigerant (A) and the second refrigerant (B) in the working fluid mixture at different points within the system.

[0052] As previously explained, the mixed refrigerant comprises two or more refrigerants (i.e., a first refrigerant (A) and a second refrigerant (B)). The difference in boiling points between the first refrigerant (A) and the second refrigerant (B) may be about 10°F or more at atmospheric pressure. The working fluid may include oil(s) at specific points within the system, which will be described in more detail below. As used herein, the term "fluid" includes liquids, gases and combinations thereof, and includes vapors (e.g., gaseous phases having aerosolized droplets). Additionally, as used herein, the terms "gas" or "gaseous phase" should be understood to include both vapors and pure gaseous phases.

[0053] The temperature control system (20) is equipped with a fluid flow path or fluid conduit (22) that provides fluid communication between components so that the working fluid can circulate in a loop as described below. First, a working fluid comprising a first refrigerant (A) and a second refrigerant (B) can enter a first heat exchanger at Point 1. The first heat exchanger may be a condenser (40). The condenser (40) receives the working fluid as a pressurized gas stream (30) and cools it to produce a condensed working fluid stream (32). In the condenser (40), the working fluid of the pressurized gas stream (30) undergoes a phase change from vapor to liquid. The working fluid is cooled through the condensation process, and in this process, heat from the temperature control system (20) is released to the outside (see air flow indicated by the arrow). The condenser (40) can be located in an indoor and / or outdoor space capable of releasing heat.

[0054] The heat exchanger (condenser (40) and evaporator (58) described below) may be of a concentric, finned tube, brazed plate, plate and frame, microchannel, or other form. The system (20) may include one condenser and one evaporator, or multiple condensers and multiple evaporators may be configured in parallel or in series. Refrigerant flow may be controlled via a capillary tube, a thermostatic expansion valve, an electric expansion valve, or other methods. In a heat pump system, the roles of the condenser (40) and evaporator (58) may be changed depending on whether the space is being heated or cooled.

[0055] In at least one aspect of the present invention, the working fluid comprising the first refrigerant (A) and the second refrigerant (B) may be condensed only partially to form a multi-phase mixture of liquid and optionally gaseous / vapor within the condensed working fluid stream (32). Thus, the working fluid exiting the condenser (40) at Point 2 may contain both the first refrigerant (A) and the second refrigerant (B) which are partially or completely liquid. In other words, the working fluid at Point 2 and within the condensed working fluid stream (32) may have a multi-phase composition.

[0056] The condensing working fluid at point 2 is circulated through the fluid conduit (22). The working fluid exiting the condenser (40) at point 2 may enter a liquid-to-suction heat exchanger (42). Generally, the liquid-to-suction heat exchanger (42) transfers heat between the relatively hot liquid refrigerant exiting the condenser (40) and the relatively cold fluid exiting the evaporator (58). The liquid-to-suction heat exchanger (42) may be further cooled before the liquid refrigerant enters the expansion valve (46).

[0057] After passing through the liquid-to-suction heat exchanger (42), the working fluid at Point 3 flows into the downstream expansion valve (46), where the pressure of the working fluid is reduced. After passing through the expansion valve (46), the working fluid at low pressure flows into the inlet of a gas-liquid / liquid-vapor separating vessel or flash tank (48).

[0058] At point 3 of the fluid conduit (22), the working fluid comprises both the first refrigerant (A) and the second refrigerant (B) in a partially or completely liquid state. As previously mentioned, in one aspect of the present invention, a mixed refrigerant working fluid comprising the first refrigerant (A) and the second refrigerant (B) is partially condensed to form a mixture having both a gaseous / vapor phase and a liquid phase. For example, the first refrigerant (A) has a low boiling point and is therefore more volatile, resulting in a lower rate of condensation into the liquid phase, while the second refrigerant (B) has a high boiling point and is therefore relatively more condensed into the liquid phase. Thus, at point 3, the first refrigerant (A) may exist more in a gaseous or vapor state, and the second refrigerant (B) may exist more in a liquid state.

[0059] By having a gas-liquid separator (e.g., flash tank) (48) within the temperature control system (20), it is possible to control or regulate how much of each refrigerant in the refrigerant mixture is directed to the downstream components of the temperature control system (20). For example, the quality or concentration (e.g., volume percentage) of the first refrigerant (A) and the second refrigerant (B) of the working fluid discharged at Point 4 after passing through the flash tank (48) can be controlled by a control module or controller (50). The control module (50) is described in more detail in the description related to FIG. 3.

[0060] At point 3 of the fluid conduit (22), at least a portion of the working fluid contains a multiphase working fluid, and this working fluid is introduced into a flash tank (48). The flash tank (48) receives the multiphase working fluid and generates a liquid stream (34). Thus, the multiphase working fluid is separated into a first or vapor portion that accumulates within the flash tank (48) and a second or liquid portion that passes through the flash tank (48) and represents the liquid stream (34) at point 4. The vapor portion may contain a liquid or vapor refrigerant, including a first refrigerant (A) which is relatively more volatile and a portion of a second refrigerant (B) which is relatively less volatile. The liquid stream (34) may contain the first refrigerant (A) and the second refrigerant (B) in a liquid phase. In some variations, most of the liquid stream (34) may be the second refrigerant (B).

[0061] The liquid stream (34) passing through the flash tank (48) passes through the filter (52) and is then directed to the expansion valve (56), where the pressure of the working fluid is further reduced. After passing through the expansion valve (56), the low-pressure working fluid is directed at Point 5 to the inlet of a second heat exchanger, such as an evaporator (58). The evaporator (58) heats the working fluid to convert the first refrigerant (A) and / or the second refrigerant (B) into a multiphase or liquid state, and discharges it at Point 6, where a cooling effect occurs through an endothermic reaction.

[0062] The evaporator (58) can be used to cool air flowing into a room or space where the temperature control system (20) is to be cooled, or into a space that requires cooling. Thus, the evaporator (58) receives a low-pressure multiphase working fluid and at least partially evaporates it to produce a working fluid stream (36) evaporated at point 6. The evaporated working fluid stream (36) is directed to a downstream liquid-suction heat exchanger (42).

[0063] After passing through the liquid-suction heat exchanger (42), at Point 7 the working fluid is directed to a downstream accumulator (60) or other storage vessel or device. The accumulator (60) may optionally be placed in the fluid conduit (22) upstream of the evaporator (58). The accumulator (60) separates the liquid, which has a relatively high concentration of the first refrigerant (A), from the vapor, which has a relatively low concentration of the first refrigerant (A).

[0064] The vapor portion of the working fluid within the accumulation section (60) flows into the compressor (62) at Point 8 in the form of a vapor stream (38). In the compressor (62), the fluid of the vapor stream (38) is compressed, causing the pressure to rise so that a high-pressure vapor or gas stream (30) is formed and discharged through the compressor. The compressor (62) may use various types of compressors known in the art. Compressors suitable for the above application can be broadly classified into positive displacement compressors and dynamic compressors. A positive displacement compressor is a method of increasing the pressure of the refrigerant vapor by reducing the volume of the compression chamber through work applied to the compressor mechanism. There are several types of positive displacement compressors currently in use, including, for example, reciprocating, rotary (rolling piston, rotary vane, single screw, twin screw), and orbital (scroll or trochoid) compressors. A dynamic compressor continuously transfers kinetic energy to the refrigerant vapor in a compression mechanism in the form of a rotating part, converting this into a pressure rise to increase the refrigerant vapor pressure. A centrifugal compressor is based on this principle. Details regarding the design and function of compressors for the refrigeration field are described in Chapter 37 of the 2010 ASHRAE Handbook, HVAC Systems and Equipment, and are incorporated by reference into this document. As a specific variation, the compressor (62) may be a scroll compressor or a reciprocating compressor.

[0065] The high-pressure gas or pressurized gas stream (30) discharged through the compressor (62) has a significantly higher pressure than the evaporated working fluid stream (36) and the steam stream (38). The mechanical energy required to compress the steam and pump the fluid in the compression mechanism of the compressor (62) can be provided, for example, by an electric motor or an internal combustion engine. In particular, in certain aspects, the temperature control system (20) can provide turndown without conventional compressor capacity variation techniques by changing the refrigerant density in the working fluid at the inlet of the compressor (62).

[0066] FIG. 2 shows a pressure versus enthalpy phase diagram at a constant temperature to explain the principle of a working fluid containing a refrigerant mixture having a high temperature gradient according to the principles of the present disclosure. It should be noted that the state points described in FIG. 2 are similarly indicated in the system of FIG. 1. In the exemplary embodiment of FIG. 2, the working fluid is a refrigerant mixture containing carbon dioxide (CO2) and R1233zde. These specific refrigerants are merely examples, and other refrigerant mixtures may be used in the temperature control system (20) of FIG. 1 according to the present disclosure.

[0067] Referring to FIG. 1-2, Point 1 represents the state of the vapor discharged through the compressor (62), where the pressure and enthalpy of the vapor are highest than at any other point in the temperature control system (20). When the working fluid enters the condenser (40) and passes through Point 2, the working fluid containing the refrigerant mixture releases heat, causing the enthalpy to decrease and the pressure to be maintained. In the case where the refrigerant is only partially condensed, Point 2 is located within the biphasic envelope (gaseous and liquid phases) instead of belonging to the liquid phase region in a traditional system.

[0068] Therefore, in the condenser (40), heat / enthalpy is removed from the two-phase fluid to form a low vapor-quality two-phase working fluid, a saturated liquid or a subcooled liquid. The working fluid passes through a liquid-suction heat exchanger (42) (Point 3), where it is cooled through heat exchange with the fluid coming out of the evaporator (58) to form a saturated liquid or a subcooled working fluid.

[0069] The pressure of the condensed and potentially subcooled fluid at point 3 is reduced at point 4 as the fluid expands while passing through a valve or orifice (e.g., expansion valve (46)), resulting in a lower pressure at the same enthalpy. After expansion (point 4), the working fluid in a low-pressure liquid or low-dryness vapor state (e.g., with a higher liquid ratio and a lower vapor / gas ratio) thus absorbs heat from the air or secondary fluid stream in the evaporator (58) to form the ideal working fluid at point 5. The refrigerant mixture enters the evaporator at point 5, absorbs heat, and increases enthalpy, causing the refrigerant to partially or completely evaporate and reach point 6. If the refrigerant evaporates only partially, the state point is also located within the ideal (gaseous and liquid phase) mixed region (biphasic envelope).

[0070] The ideal working fluid discharged at Point 6 after passing through the evaporator (58) is further heated through heat exchange with the fluid coming out of the condenser (40) at Point 7, becoming an ideal working fluid with high vapor dryness (high vapor ratio) (containing relatively more vapor / gas). At Point 8, the working fluid flows into the compressor (62), and the vapor pressure rises to reach the discharge state at Point 1.

[0071] FIG. 3 is a block diagram showing communication between a component of the temperature control system (20) of FIG. 1 and a control module (50) (also referred to as a controller (50)) in at least one exemplary embodiment.

[0072] In various aspects, the control module (50) can be used to enable, disable, or modulate the operation of various components and devices of the temperature control system (20), including compressor(s), fan(s), pump(s), valve(s), storage container(s), etc. The control module (50) may receive input from various sensors (100) within the temperature control system (20), such as a temperature sensor, a pressure sensor, a capacitance sensor, a flow sensor (volumetric flow sensor, etc.), an acoustic velocity sensor (e.g., a sonic velocity sensor), a current / voltage meter, etc. In the example of FIG. 3, the control module (50) may receive input from a pressure sensor (500) (e.g., the sensor (500) of FIG. 5), a capacitance sensor (600) (e.g., the sensor (600) of FIG. 6), an acoustic velocity sensor (700) (e.g., the sensor (700) of FIG. 7), a pressure sensor (800) (e.g., the first sensor (800) of FIG. 8), a temperature sensor (802) (e.g., the second sensor (802) of FIG. 8), a flow sensor (804) (e.g., the third sensor (804) of FIG. 8), and / or a flow sensor (806) (e.g. Input can be received from the fourth sensor (806) of 8, etc. Detailed information regarding the sensor (100) will be described later together with FIGS. 5 to 8.

[0073] Accordingly, the control module (50) can open, close, regulate, or guide the flow of working fluid (or a portion of working fluid, e.g., the flow of a first refrigerant and / or a second refrigerant) to / from various components and devices within the system, including a condenser (40), a heat exchanger (42), an expansion valve (46), a gas-liquid separator (48), a filter (52), an evaporator (58), an accumulator (60), a compressor (62), a storage vessel (e.g., a receiver (80) in FIG. 11), and a liquid pump (e.g., a liquid pump (64) in FIG. 9 and FIG. 10). Although only one control module (50) is shown as an example in FIG. 1, any number of control modules (50) receiving data from any number of sensors (100) can be utilized to achieve the desired fluid flow characteristics of the temperature control system (20). In addition, sensors (100) of other quantities, types, and combinations may also be utilized.

[0074] In at least one exemplary embodiment, the control module (50) can communicate with a remote computer (120), thereby allowing a remote user to monitor, control, and adjust the operation of the control module (50).

[0075] In at least one exemplary embodiment, the control module (50) can communicate with a building automation system (BAS) (122). The BAS (122) may be connected to additional temperature and pressure sensors and may monitor and store additional temperature and pressure data that the control module (50) can access in the event of a sensor failure. A remote computer (120) may also be connected to the BAS (122) so that a remote user can log into the BAS (122) to monitor, control, or adjust the operation of any controller, including the control module (50).

[0076] As previously discussed, control of a temperature control system (e.g., the temperature control system (20) of FIG. 1, the control system (920) of FIG. 9, and / or the control system (1020) of FIG. 10), including control of the amount or volume of working fluid circulating through the various components described above in various aspects, may be performed by one or more control modules (e.g., the control module (50)). In this application, the terms “module” or “controller” may be replaced by the term “circuit,” including the definitions below. The term “module” may be some of or include the following: an application-specific integrated circuit (ASIC); a digital, analog, or analog / digital discrete circuit; a digital, analog, or analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit for code execution (shared, private, or group); a memory circuit for storing code executed by the processor circuit (shared, private, or group); Other suitable hardware components that provide the above functions; or a combination of some or all of the above items, for example, a System-on-Chip (SoC).

[0077] The control module (50) may include one or more interface circuits. In some examples, the interface circuit may include a wireless or wired interface connected by a LAN, the Internet, a WAN, or a combination thereof. The functions of the control module (50) of the present application disclosure may be distributed among a plurality of control modules (50) connected by the interface circuits. For example, the plurality of control modules (50) may enable load balancing. In other examples, a server module (also referred to as a remote or cloud module) may perform some functions on behalf of the client module.

[0078] The term "code" mentioned above may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects, etc. A shared processor circuit includes a single processor circuit that executes part or all of the code of multiple modules. A group processor circuit includes a processor circuit that executes part or all of the code of one or more modules in combination with additional processor circuits. When referring to multiple processor circuits, they include multiple processor circuits on individual dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination thereof. A shared memory circuit includes a single memory circuit that stores part or all of the code of multiple modules. A group memory circuit includes a memory circuit that stores part or all of the code of one or more modules in combination with additional memory.

[0079] A memory circuit is a subset of a computer-readable medium. As used in this application, a computer-readable medium does not include transient electrical or electromagnetic signals propagating through a medium (e.g., a carrier); a computer-readable medium may be considered a substantial and non-transitory medium. Non-limiting examples of a non-transitory and tangible computer-readable medium are as follows: non-volatile memory circuits (flash memory circuits, eraseable ROM circuits, mask ROM circuits, etc.), volatile memory circuits (SRAM circuits or DRAM circuits), magnetic storage media (analog or digital magnetic tape, hard disks), and optical storage media (CDs, DVDs, Blu-ray discs).

[0080] The apparatus and method described in this application may be partially or fully implemented by a special-purpose computer (e.g., remote computer (120)) configured to perform one or more specific functions implemented in a computer program of a general-purpose computer. The function blocks, flowchart components, and other elements described above serve as software specifications and can be converted into code by a person skilled in the art or a programmer through ordinary work.

[0081] A computer program comprises processor-executable instructions stored on at least one non-transient, tangible computer-readable medium. A computer program may also include or rely on stored data. A computer program may include a Basic Input / Output System (BIOS) that interacts with the hardware of a special-purpose computer, a device driver that interacts with a specific device of the special-purpose computer, one or more operating systems, user applications, background services, and background applications.

[0082] A computer program may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation); (ii) assembly code; (iii) object code generated from source code by a compiler; (iv) source code executed by an interpreter; (v) source code compiled and executed by a JIT compiler, etc. By way of example only, source code may be C, C++, C#, Objective C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th Revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic ® , Lua, MATLAB, SIMULINK, and Python ® It can be written using syntax from a language that includes.

[0083] The control module (50) may include one or more modules (50) and may be implemented as part of a control board, furnace board, thermostat, air handler board, contactor, or other form of control system or diagnostic system. The control module (50) may include power conditioning circuitry for supplying power to various components, and power supply such as 24V AC, 120-240V AC, 5V DC, etc. The control module (50) may include wired, wireless, or wired / wireless bidirectional communication, through which system debugging, programming, updating, monitoring, and transmission of parameter values / status can be performed.

[0084] In various aspects, the sensor (100) measures the characteristics of the working fluid (e.g., pressure, temperature, dielectric constant, density, acoustic velocity (e.g., speed of sound, etc.) at a specific location designated in advance within the fluid conduit (22). The control module (50) receives measurements from one or more sensors (100). Based on this, the control module (50) can determine necessary modifications for the temperature control system (20). For example, the control module (50) can determine the concentration or composition of the working fluid at any location in the temperature control system (20). In particular, the control module (50) receives measurements regarding the working fluid characteristics of the first refrigerant (A) and the second refrigerant (B), and can calculate the concentration of the first refrigerant (first concentration) and the concentration of the second refrigerant (second concentration) as a function of the working fluid characteristics. Subsequently, based on the determined composition, the control module (50) controls the operation of the temperature control system (20), for example, the condenser (40), heat exchanger (42), expansion valve (46), The operation of a gas-liquid separator (48), a filter (52), an expansion valve (56), an evaporator (58), an accumulation section (60), a compressor (62), a storage container (not shown), and a liquid pump (64) (e.g., the liquid pump (64) of FIG. 9 and FIG. 10) can be controlled. For example, the control module (50) can control the flow of working fluid circulating through the temperature control system (20) by opening or closing a valve, or control the composition of the mixed working fluid to change (e.g., the addition of a first refrigerant (A) and / or a second refrigerant (B) at a specific location). As another example, the control module (50) can compare the determined working fluid composition with a stored threshold value (design value) and provide a signal or instruction to one or more components of the temperature control system (20) to adjust the operation of the components.

[0085] In various aspects, the present disclosure relates to a control algorithm or method for detecting the composition of a refrigerant in a working fluid. For example, the method may include the step of detecting the concentrations of a first refrigerant (A) and a second refrigerant (B), and the step of determining the composition of the working fluid.

[0086] FIG. 4 is a flowchart showing a control algorithm for determining the composition of the refrigerant in the working fluid of the temperature control system (20) of FIG. 1.

[0087] The control algorithm starts at S100. The control algorithm may start automatically or after receiving an instruction.

[0088] In S102, the control algorithm uses the control module (50) to determine whether the working fluid is flowing through the fluid conduit (22). If the working fluid is not flowing through the fluid conduit (22), the algorithm returns to S102. If the working fluid is flowing through the fluid conduit (22), the algorithm proceeds to S104.

[0089] In S104, the control algorithm receives data from one or more sensors and detects one or more characteristics of the working fluid. As described in more detail in relation to FIG. 5-8, one or more sensors (100) are configured to detect or measure the characteristics of the working fluid flowing through the fluid conduit (22). The method then proceeds to S106.

[0090] In S106, the control algorithm calculates or determines the composition of the working fluid. The calculation may include the process of calculating the concentration of the first refrigerant (A) and the concentration of the second refrigerant (B) based on the characteristics detected in S104 and the information stored in the memory of the temperature control system (20).

[0091] Information stored in the memory of the system (20) may include values, tables, graphs, formulas, and / or the presence or absence of refrigerant characteristics. The memory may contain information regarding various refrigerants. In some exemplary embodiments, the stored information may include a number of stored values, and the number of stored values ​​may include values ​​for a first refrigerant (A) and values ​​for a second refrigerant (B). For example, the values ​​may include mass, density under various conditions, dielectric constant and / or liquid acoustic velocity and / or sound speed, etc. The values ​​may be independent of other refrigerant and / or system information. Additionally, or alternatively, the values ​​may be determined dependently on other refrigerant and / or system information (e.g., temperature at a specific point within the system). In this case, the control module (50) may determine the values ​​using tables, graphs, and / or formulas. Other refrigerant and / or system information may be provided in other measurements (e.g., sensor measurements), system setpoints, and / or system assumptions.

[0092] In some aspects, after determining the composition of the working fluid in S106, the control algorithm may return to S102. Additionally or alternatively, as discussed below, after determining the composition of the working fluid in S106, the control algorithm may optionally modify the operation of the control system (20) in S108. In other aspects, after determining the composition of the working fluid in S106, the control algorithm may terminate.

[0093] In S108, the control algorithm can modify the operation of components of the temperature control system (20), such as a condenser (40), a heat exchanger (42), an expansion valve (46), a gas-liquid separator (48), a filter (52), an expansion valve (56), an evaporator (58), an accumulator (60), a compressor (62), a storage container (e.g., the receiving portion (80) of FIG. 11), and a liquid pump (e.g., the liquid pump (64) of FIG. 9 and 10), based on the calculated working fluid composition. For example, a determined composition is provided to the control module (50), and the control module (50) controls one or more components of the temperature control system (20) based on the determined composition, thereby causing one or more components to modify their operation according to the composition. This may include starting, stopping, or pausing the operation of one or more components of the temperature control system (20). As another example, the control algorithm may add amounts of the first refrigerant (A) and / or the second refrigerant (B) to achieve a predetermined (or alternatively desired) target composition (e.g., a target composition of the mixed working fluid at a specific location).

[0094] As previously mentioned, the sensor (100) can measure or detect characteristics of the working fluid (e.g., pressure, temperature, dielectric constant, density, acoustic velocity, etc.) at a predetermined location or a desired specific location of the fluid conduit (22). In this specification, "detection" refers to the output information of the sensor. The characteristics may be detected directly or indirectly by one or more sensors (200). That is, the output of each sensor (100) may be based on the detected characteristics of the working fluid, and the detected characteristics may be selected from the group consisting of pressure, temperature, dielectric constant, density, acoustic velocity (e.g., sound velocity), or a combination thereof.

[0096] The sensor (100) can be installed at various locations suitable for measuring the characteristics of the fluid in the fluid conduit (22). For example, if the control module (50) is associated with the gas-liquid separator (48), the sensor (100) can be installed immediately upstream and / or immediately downstream of the gas-liquid separator (48). Additionally or alternatively, if the control module (50) is associated with the accumulation unit (60), the sensor (100) can be installed immediately upstream and / or immediately downstream of the accumulation unit (60). Additionally or alternatively, if the control module (50) is associated with the compressor (62), the sensor (100) can be installed immediately upstream and / or immediately downstream of the compressor (62). Additionally or alternatively, if the control module (50) is associated with a liquid pump (64) (e.g., the liquid pump (64) of FIG. 9, 10), the sensor (100) may be installed immediately before and / or immediately after the liquid pump. In some aspects, one or more sensors may be integrated into the component itself, for example, into the gas-liquid separator (48), the accumulation unit (60), the compressor (62), the fluid conduit (22), and / or the liquid pump (64).

[0097] In some aspects, the sensor (100) may be located outside the fluid flow path (i.e., outside the fluid conduit (22)) (e.g., sensor (500) of FIG. 5). In some aspects, the sensor may be located inside the fluid flow path (inside the fluid conduit (22)) (e.g., sensor (600) of FIG. 6, sensor (700) of FIG. 7). In some aspects, the sensor (100) may be located within a storage container such as a gas-liquid separator (48) and / or an accumulation unit (60) (e.g., sensor (800), 802) of FIG. 8).

[0098] In various aspects, the calculation of the working fluid composition may be based on detected characteristics and stored information. The stored information includes a first stored value and a second stored value. In some embodiments, there may be three or fewer detected characteristics (e.g., three detected characteristics, two detected characteristics, one detected characteristic). In some embodiments, the control module (50) may determine the composition with only a single point measurement (see FIG. 5-7). That is, the control module (50) may determine or calculate the working fluid composition based on one detected characteristic (i.e., one measurement value) from the sensor. In some embodiments, the one detected characteristic may be one of pressure (if the sensor (100) is a pressure sensor (500)), capacitance (if the sensor (100) is a sensor (600)), or acoustic velocity (if the sensor (100) is a sensor (700)). In some embodiments, the working fluid composition can be calculated using only one detected characteristic, independently of other detected characteristics (e.g., measurements from other sensors of the temperature control system (20)).

[0099] FIG. 5 is a schematic diagram of an example of a sensor (500) communicating with a control module (50) (shown in FIG. 3). That is, the control module (50) receives data from the sensor (500). The sensor (500) is a pressure sensor. The sensor (500) may be attached to a pipe (501) extending between a fluid inlet (502) and a fluid outlet (504). The fluid inlet (502) and the fluid outlet (504) are in fluid communication with a fluid conduit (22). A portion of the working fluid flowing through the fluid conduit (22) may enter the pipe (501) from the fluid inlet (502), flow along the pipe (501), exit through the fluid outlet (504), and then return to the fluid conduit. In some aspects, the pipe (501) may be heated, for example, to boil all or part of the working fluid passing through the sensor (500). The sensor (500) measures or detects the pressure of the working fluid flowing through the pipe (501) and provides the measured value to the control module (50). For example, the sensor (500) can measure or detect the differential pressure of the working fluid passing through the pipe (501) at a fixed dimension (506) (i.e., the height of the pipe (501)).

[0100] In some aspects, the sensor (500) may be positioned outside the pipe (501) (e.g., attached to the pipe (501)). In other aspects, the sensor (500) may be positioned inside the pipe (501) and configured so that the working fluid flows through the pipe (501) and comes into direct contact with the sensor (500).

[0101] In various aspects, the concentrations of the first refrigerant (A) and the second refrigerant (B) are calculated based on pressure measurements from the sensor (500) and stored information. The stored information includes a first density of the first refrigerant (A) and a second density of the second refrigerant (B) that is different from the first density. The first density and the second density may be based on a known temperature (e.g., a set value and / or an assumed value based on other system characteristics, or a detected value). Thus, the stored information may include temperature-density data for the first refrigerant and the second refrigerant. After receiving pressure measurements from the sensor (500), the control module (50) may calculate or determine the first concentration of the first refrigerant and the second concentration of the second refrigerant as a function of the first density, the second density, and the pressure measurements. In some embodiments, the composition of the working fluid is calculated based solely on pressure measurements and stored information. Also, in some embodiments, the calculation may be performed based on the detected pressure and stored information without relying on any other detected characteristics. The composition of the mixed working fluid is determined by the following formula:

[0102]

[0103] In the above equation, C wf is the concentration of the mixed working fluid, and P m is the measured pressure of the working fluid flowing through the pipe (501), and P A is the estimated pressure of the first refrigerant (A) based on the first density, and P B is the estimated pressure of the second refrigerant (B) based on the second density. The pressure of the first refrigerant (P A ) and pressure of the second refrigerant (P B ) can be estimated based on known relationships (e.g., known formulas) and / or stored information.

[0104] FIG. 6 shows a schematic diagram of another example of a sensor (600) communicating with a control module (50) (shown in FIG. 3). In other words, the control module (50) receives data from the sensor (600). The sensor (600) may be a capacitive sensor. The sensor (600) may be placed inside a fluid conduit (22) and configured so that a working fluid flows around the sensor (600).

[0105] In various aspects, the concentrations of the first refrigerant (A) and the second refrigerant (B) are calculated based on the capacitance measurements of the sensor (600) and stored information. The stored information includes the first dielectric constant of the first refrigerant (A) and the second dielectric constant of the second refrigerant (B), which is different from the first dielectric constant. The sensor (600) measures or detects the pressure or capacitance of the working fluid based on the current of the working fluid and provides the measured values ​​to the control module (50). In some embodiments, the first dielectric constant and the second dielectric constant may be determined based on previously detected measurements (e.g., partial pressure of each component) and a table stored in the system memory.

[0106] After receiving a capacitance measurement from the sensor (600), the control module (50) may calculate or determine a first concentration of the first refrigerant (A) and a second concentration of the second refrigerant (B) as a function of the first dielectric constant, the second dielectric constant, and the capacitance measurement. In some embodiments, the calculation is performed based on the detected capacitance and stored information and may not depend on other detected characteristics (e.g., characteristics detected in real time).

[0107] FIG. 7 shows a schematic diagram of another example sensor (700) communicating with a control module (50) (shown in FIG. 3). That is, the control module (50) receives data from the sensor (700). The sensor (700) may be an acoustic velocity sensor. In one example, the sensor (700) may be a sonic velocity sensor. The sensor (700) may include an acoustic transmitter (702) and an acoustic receiver (704) located downstream of the transmitter (702). If the sensor (700) is a sonic velocity sensor, the sensor (700) may include a sonic transmitter (702) and a sonic receiver (704) located downstream of the transmitter (702). An operating fluid flows through a fluid conduit (22) between the acoustic transmitter (702) and the acoustic receiver (704).

[0108] In various aspects, the concentrations of the first refrigerant (A) and the second refrigerant (B) are calculated based on acoustic velocity measurements from the sensor (700) and stored information. The stored information includes the first liquid acoustic velocity of the first refrigerant (A) and the second liquid acoustic velocity of the second refrigerant (B), and these two velocities are different. In some embodiments, the first liquid acoustic velocity may be the first acoustic velocity and the second liquid acoustic velocity may be the second acoustic velocity. In some embodiments, the first liquid acoustic velocity and the second liquid acoustic velocity may be estimated based on previously detected measurements and a table stored in system memory.

[0109] When flowing through the fluid conduit (22), the first refrigerant and the second refrigerant can transmit different frequencies. The sensor (700) measures the acoustic velocity of the working fluid and provides this measurement value to the control module (50). After receiving the acoustic velocity measurement value from the sensor (700), the control module (50) can calculate the concentration of the first refrigerant (A) and the concentration of the second refrigerant (B) as a function of the first liquid acoustic velocity, the second liquid acoustic velocity, and the acoustic velocity measurement value. In some embodiments, the composition of the working fluid is calculated based only on the acoustic velocity measurement value and stored information. In some embodiments, the calculation is performed based on the detected acoustic velocity and stored information and is performed independently of other detected characteristics.

[0110] In some respects, the control module (50) may be configured to determine the composition of the working fluid by utilizing two or more sensor measurements (e.g., a combination of sensor measurements). FIG. 8 shows another example schematic diagram of a first sensor (800), a second sensor (802), a third sensor (804), and a fourth sensor (806), each of which measures the characteristics of the working fluid of the temperature control system (20). The control module (50) (shown in FIG. 3) can communicate with the first sensor (800), the second sensor (802), the third sensor (804), and the fourth sensor (806). That is, the control module (50) receives data from the sensors (800, 802, 804, 806). The control module (50) determines the concentration of the working fluid based on the measurements of each sensor (800, 802, 804, 806). In a specific aspect, the control module (50) may be configured to control the amount of working fluid coming out of the gas-liquid separator (48). In particular, the control module (50) may be utilized in temperature control systems including a liquid pump located downstream of the gas-liquid separator (48) (e.g., the temperature control system (920) of FIG. 9 and the temperature control system (1020) of FIG. 10).

[0111] The first sensor (800) may be a pressure sensor. The first sensor (800) may be placed in a gas-liquid separator (48). The first sensor (800) is configured to measure the pressure of the working fluid within the gas-liquid separator (48).

[0112] The second sensor (802) may be a temperature sensor. The second sensor (802) may be placed in the gas-liquid separator (48). The second sensor (802) is configured to measure the temperature of the working fluid within the gas-liquid separator (48). In certain aspects, either the first sensor (800) or the second sensor (802) may be omitted.

[0113] The third sensor (804) may be a flow rate sensor. The third sensor (804) may be placed immediately upstream (immediately before), immediately downstream (immediately after) the compressor (62), or inside the compressor (62). The compressor (62) is located downstream of the gas-liquid separator (48) and receives a portion of the working fluid in a vapor state from the gas-liquid separator (48) (e.g., the vapor stream (38) of FIG. 9 and 10). The third sensor (804) is configured to measure a first flow rate of a first portion of the working fluid passing through the compressor (62).

[0114] The fourth sensor (806) may be a flow sensor. The fourth sensor (806) may be positioned immediately upstream, immediately downstream, or inside the liquid pump (64) (the liquid pump (64) is described in detail in the description of FIGS. 9 and 10). The liquid pump (64) is located downstream of the gas-liquid separator (48) and receives a second portion of the multiphase or liquid working fluid from the gas-liquid separator (48) (e.g., the liquid stream (40) in FIGS. 9 and 10). The fourth sensor (806) is configured to measure the second flow rate of the second portion of the working fluid passing through the liquid pump (64).

[0115] The pressure measurement value of the first sensor (800), the temperature measurement value of the second sensor (802), the flow rate measurement value of the third sensor (804), and the flow rate measurement value of the fourth sensor (806) are received by the control module (50). The control module (50) can determine or calculate the concentration of the first refrigerant (A) and the concentration of the second refrigerant (B) using the pressure measurement value of the first sensor (800), the temperature measurement value of the second sensor (802), the first flow rate measurement value of the third sensor (804), and the second flow rate measurement value of the fourth sensor (806) as functions. Composition of working fluid C wf is calculated by the following formula:

[0116]

[0117] In the above equation, C v is the concentration of the first refrigerant (A), m c is the first flow rate, C i is the concentration of the second refrigerant (B), m p means the second flow rate.

[0118] FIG. 9 shows another embodiment of a temperature control system in the form of a heat pump system (920) (also referred to as the "temperature control system (920)"). The temperature control system (920) is identical or similar to the temperature control system (20) of FIG. 1, except as otherwise described below. Where the components and working fluid flow points described in FIG. 1 are similar, the same reference numerals are used and are not described again here for brevity. A person skilled in the art will understand that the features and components described in connection with FIG. 9 may be used individually or in combination in the temperature control systems described in FIG. 1 and FIG. 10.

[0119] The working fluid enters the condenser (40) at point 1 and exits the condenser as a condensed working fluid stream (32) at point 2. The working fluid passes through the liquid-suction heat exchanger (42) and is guided to the expansion valve (46). Then, the working fluid enters the evaporator (58) at point 5 and exits the evaporator as an evaporated working fluid stream (36) at point 6. The working fluid passes through the liquid-suction heat exchanger (42) again. At point 7, the working fluid is guided to the gas-liquid separator (48).

[0120] The gas-liquid separator (48) separates the working fluid into a first part in a vapor state and a second part in a multiphase or liquid state. The working fluid exits the gas-liquid separator (48) as two different fluid streams.

[0121] At point 8, the first portion of the working fluid exits the gas-liquid separator (48) as a steam working fluid stream (38). The first portion of the working fluid is guided to a compressor (62) located downstream of the gas-liquid separator (48).

[0122] At point 9, a second portion of the working fluid exits the gas-liquid separator (48) as a multiphase or liquid working fluid stream (40). The second portion of the working fluid is guided to a liquid pump (64). The liquid pump (64) is configured to increase the pressure of the working fluid. After passing through the liquid pump (64), the working fluid of the second portion exiting the liquid pump (64) and the working fluid of the first portion exiting the compressor (62) are combined into a pressurized gas stream (30) and recirculated through the condenser (40) at point 1.

[0123] The temperature control system (920) includes one or more control modules (50) associated with one or more components (e.g., gas-liquid separator (48), compressor (62), and / or liquid pump (64)). The control modules (50) are configured to detect the concentration of the working fluid passing through the components and to regulate and / or control the amount of working fluid entering or exiting the components.

[0124] FIG. 10 shows another embodiment of a temperature control system in the form of a heat pump system (1020) (also referred to as the "temperature control system (1020)"). The temperature control system (1020) is identical or similar to the temperature control system (920) and is the same except as otherwise described below. Where the components and working fluid flow points described in FIG. 1 and / or FIG. 9 are similar, the same reference numerals are used and are not described again here for brevity. A person skilled in the art will understand that the features and components described in connection with FIG. 10 may be used individually or in combination in the temperature control systems described in FIG. 1 and FIG. 9.

[0125] The temperature control system (1020) includes one or more reversing valves or four-way valves (70) (e.g., a pair of reversing valves (70)). The reversing valves (70) enable both heating and cooling functions to be used in the temperature control system (1020). The reversing valves (70) maintain the working fluid counterflow against the air in heating and cooling operating modes. A person skilled in the art will understand that the temperature control system (1020) can set different directions of flow of the working fluid within the system.

[0126] The temperature control system (1020) includes one or more control modules (50) associated with one or more components (e.g., gas-liquid separator (48), compressor (62), liquid pump (64) and / or switching valve (70)). The control module (50) is configured to detect the concentration of the working fluid passing through the component and to regulate and control the amount of working fluid entering or exiting the component.

[0127] FIG. 11 shows another embodiment of a temperature control system (1120). The temperature control system (1120) is identical or similar to the temperature control system (20), except as otherwise described below. Where the components and working fluid flow points described in FIG. 1, FIG. 9 and / or FIG. 10 are similar, the same reference numerals are used and are not described again here for brevity. A person skilled in the art will understand that the features and components described in connection with FIG. 11 may be used individually or in combination in the temperature control systems described in FIG. 1, FIG. 9 and FIG. 10.

[0128] The working fluid enters the condenser (40) at point 1 and exits the condenser as a condensed working fluid stream (32) at point 2. The working fluid passes through the liquid-suction heat exchanger (42) and is guided to the expansion valve (46). The expansion valve (46) is located downstream of the liquid-suction heat exchanger (42) and upstream of the storage vessel (80) ("receiving section (80)"). The working fluid is then guided to the receiving section (80). In the receiving section (80), the working fluid circulating through the fluid conduit (22) can be stored and concentrated. The receiving section (80) can receive the working fluid having both vapor and liquid phases, but most of the fluid may be in the liquid phase.

[0129] The working fluid exits the receiving section (80) and is guided to the expansion valve (56). The expansion valve (56) is located downstream of the receiving section (80) and upstream of the evaporator (58). The operation of the expansion valve (56) can be controlled by the control module (50). The expansion valve (56) is configured to reduce the pressure of the working fluid.

[0130] After that, the working fluid enters the evaporator (58) at point 5 and exits the evaporator as an evaporated working fluid stream (36) at point 6. The working fluid passes through the liquid-suction heat exchanger (42). After that, the working fluid is guided to the accumulation section (60) and then to the compressor (62). After passing through the compressor (62), the working fluid comes out as a high-pressure steam or gas stream (30) and is guided to the condenser (40).

[0131] The description of the above embodiments is provided for the purposes of illustration and explanation. It is not intended to be comprehensive or to limit the scope of disclosure. Individual elements or features of a particular embodiment are generally not limited to that embodiment and, where applicable, may be interchangeable and used in selected embodiments without being specifically illustrated or described. The same elements or features may be modified in various ways, and such modifications are not deemed to be outside the scope of the present disclosure, and all modifications are deemed to be included within the scope of the present disclosure.

Claims

Claim 1 A method for determining the composition of a mixed working fluid in a temperature control system, wherein the method comprises: a detection step of detecting the pressure of the mixed working fluid within the separator using a first sensor installed inside the separator, wherein the separator is configured to separate the mixed working fluid into a first part of a first phase and a second part of a second phase; a step of detecting the temperature of the mixed working fluid within the separator using a second sensor installed inside the separator; a step of detecting a first flow rate of the first part of the working fluid using a third sensor connected to the compressor when the first part of the working fluid flows through a compressor located downstream of the separator; and a step of detecting a second flow rate of the second part of the working fluid using a fourth sensor connected to the pump when the second part of the working fluid flows through a pump located downstream of the separator. and, a determination step for determining the composition of the mixed working fluid; wherein the determination step comprises: calculating the concentration of the first refrigerant of the mixed working fluid based on the pressure, the temperature, the first flow rate and the second flow rate; and calculating the concentration of the second refrigerant of the mixed working fluid based on the pressure, the temperature, the first flow rate and the second flow rate. Claim 2 The method of claim 1 further comprises the step of changing the operation of a component of the temperature control system based on the composition. Claim 3 The method of claim 1 further comprises the step of adding, based on the composition, (i) a certain amount of the first refrigerant, (ii) a certain amount of the second refrigerant, or (i) a certain amount of both the first refrigerant and (ii) the second refrigerant to the temperature control system. Claim 4 In claim 1, the method wherein the mixed working fluid is a high temperature gradient refrigerant mixture. Claim 5 A method according to claim 1, wherein the third sensor is a flow sensor that measures the first flow rate of the first portion of the working fluid in the vapor phase between the compressor and the separator. Claim 6 A method according to claim 1, wherein the fourth sensor is a flow sensor that measures the second flow rate of the second portion of the working fluid, which is liquid or multiphase, between the pump and the separator. Claim 7 A method according to claim 1, wherein the concentration of the first refrigerant of the mixed working fluid and the concentration of the second refrigerant of the mixed working fluid are calculated as a function of the pressure measured by the first sensor, the temperature measured by the second sensor, the first flow rate measured by the third sensor, and the second flow rate measured by the fourth sensor. Claim 8 In paragraph 7, the above method is formula (1) The composition C of the above-mentioned mixed working fluid by wf It further includes calculating, and C in the above equation (1). v is the above-mentioned first refrigerant concentration, m c is the above first flow rate, C i is the concentration of the second refrigerant, m p is the above second flow rate, method. Claim 9 In claim 1, the method further comprises the step of controlling the operation of the temperature control system based on the concentration of the first refrigerant, the concentration of the second refrigerant, and / or the composition of the mixed working fluid. Claim 10 In claim 9, the step of controlling the operation of the temperature control system comprises: controlling the operation of at least one of a condenser, a heat exchanger, an expansion valve, a gas-liquid separator, a filter, an expansion valve, an evaporator, an accumulator, a compressor, a storage vessel, and / or a liquid pump. Claim 11 In claim 10, the step of controlling the operation of the temperature control system comprises opening and / or closing a valve to control the flow of the mixed working fluid through the temperature control system. Claim 12 In claim 10, the step of controlling the operation of the temperature control system comprises changing the composition of the mixed working fluid. Claim 13 A method according to claim 14, wherein changing the composition of the mixed working fluid comprises adding a certain amount of the first refrigerant and / or the second refrigerant to the temperature control system. Claim 14 In claim 9, the step of controlling the operation of the temperature control system comprises comparing the concentration of the first refrigerant, the concentration and / or composition of the second refrigerant of the mixed working fluid with a stored threshold value. Claim 15 In claim 14, the step of controlling the operation of the temperature control system comprises controlling to change the operation of one or more components of the temperature control system based on the result of comparison with the stored threshold value.

Images