Device, System, and Method for Determining Charge Settings for a Refrigeration Circuit

This patent application claims the benefit of U.S. Provisional Patent Application No. 63/653,121, filed on May 29, 2024, which is incorporated by reference herein in its entirety.

Embodiments described herein relate to the field of refrigeration circuits, and more particularly, to a device, system, and method for determining charge settings for a refrigeration circuit associated with an HVAC system.

Disclosed herein is a system for determining charge settings for a refrigeration circuit of an HVAC unit. The system comprises the HVAC unit and a controller comprising one or more processors coupled to a memory storing instructions executable by the one or more processors, wherein the controller is configured to receive a set of data pertaining to an operating environment of the HVAC unit and an internal volume of the refrigeration circuit, estimate a saturated suction temperature of a refrigerant in the refrigeration circuit based on the operating environment, and determine a weight of the refrigerant to be added to the refrigeration circuit or a subcooling target temperature for a liquid line associated with the refrigeration circuit based on the estimated saturated suction temperature and the internal volume.

In one or more embodiments, the operating environment is selected from one of a humid condition, a semi-arid condition, and a desert condition.

In one or more embodiments, the humid condition pertains to a first range of humidity, a semi-arid condition pertains to a second range of humidity, and a desert condition pertains to a third range of humidity, wherein the first range is greater than the second range and the second range is greater than the third range.

In one or more embodiments, the controller is further configured to receive another set of data pertaining to one or more of an internal volume of an evaporator associated with the HVAC unit, configuration of the evaporator, and characteristics of the refrigerant, and determine the weight of the refrigerant to be allocated for the evaporator based on the received another set of data and the operating environment of the HVAC unit.

In one or more embodiments, the controller is in communication with an input unit, the input unit configured to enable a registered user to select or enter the environment type and/or the internal volume into the controller.

In one or more embodiments, the controller is in communication with an output unit, the output unit configured to display the determined weight of the refrigerant to be added to the refrigeration circuit or the determined subcooling target temperature for the liquid line, and/or the determined weight of the refrigerant to be allocated for the evaporator.

In one or more embodiments, the input unit and the output unit are associated with a thermostat of the HVAC unit, and the controller is associated with a central server.

In one or more embodiments, the input unit, the controller, and the output unit are associated with a thermostat of the HVAC unit.

In one or more embodiments, the system further comprises a humidity sensor in communication with the controller and configured to monitor specific humidity or relative humidity around an outdoor coil of the HVAC unit, wherein the controller is further configured to determine the operating environment of the HVAC unit based on the monitored humidity.

Also described herein is a device for determining charge settings for a refrigeration circuit of an HVAC unit. The device comprises an input unit configured to enable selection or entering of an operating environment of the HVAC unit and an internal volume of the refrigeration circuit, and a controller operatively connected to the input unit, the controller comprising one or more processors coupled to a memory storing instructions executable by the one or more processors, wherein the controller is configured to receive a set of data pertaining to the selected or entered operating environment and the internal volume, estimate a saturated suction temperature of a refrigerant in the refrigeration circuit based on the operating environment, and determine a weight of the refrigerant to be added to the refrigeration circuit or a subcooling target temperature for a liquid line associated with the refrigeration circuit based on the estimated saturated suction temperature and the internal volume.

In one or more embodiments, the device is further configured to receive another set of data pertaining to one or more of an internal volume of an evaporator associated with the HVAC unit, configuration of the evaporator, and characteristics of the refrigerant, and determine the weight of the refrigerant to be allocated for the evaporator based on the received another set of data and the operating environment of the HVAC unit.

In one or more embodiments, the device further comprises an output unit operatively connected to the controller, the output unit configured to display the determined weight of the refrigerant to be added to the refrigeration circuit or the determined subcooling target temperature for the liquid line, and/or the weight of the refrigerant to be allocated for the evaporator.

In one or more embodiments, the device is in communication with a humidity sensor to monitor specific humidity or relative humidity around an outdoor coil of the HVAC unit, wherein the controller is configured to determine the operating environment of the HVAC unit based on the monitored humidity.

In one or more embodiments, the device is a thermostat associated with the HVAC unit.

In one or more embodiments, the device is a mobile device associated with the registered user.

Further described herein is a method for determining charge settings for a refrigeration circuit of an HVAC unit. The method comprises receiving, by an input unit or a controller, a set of data pertaining to an operating environment of the HVAC unit and an internal volume of with the refrigeration circuit, estimating, by the controller, a saturated suction temperature of a refrigerant in the refrigeration circuit based on the operating environment, and determining, by the controller, a weight of the refrigerant to be added to the refrigeration circuit or a subcooling target temperature for a liquid line associated with the refrigeration circuit based on the estimated saturated suction temperature and the internal volume.

In one or more embodiments, the method further comprises the step of displaying, on an output unit, the determined weight of the refrigerant to be added to the refrigeration circuit or the determined subcooling target temperature for the liquid line.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, features, and techniques of the subject disclosure will become more apparent from the following description taken in conjunction with the drawings.

The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject disclosure as defined by the appended claims.

Various terms are used herein. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the subject disclosure, the components described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” “first,” “second” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components.

Split heating, ventilation, and air conditioning (HVAC) systems are employed for maintaining comfortable indoor environments in various climatic conditions. These systems operate by circulating a refrigerant through a closed refrigeration circuit, which may include a condenser and evaporators connected by refrigerant lines, to transfer heat either into or out of the indoor space. Proper charging of the refrigerant circuit is important for the HVAC system's efficiency, operational effectiveness, and longevity.

Traditional methods of charging refrigerant in HVAC systems involve either targeting a specific level of subcooling or charging the system with a (predetermined) weight/amount of refrigerant. The subcooling method adjusts the refrigerant charge based on the temperature difference between the refrigerant and the saturation temperature of the refrigerant in the vapor line of the refrigeration circuit, aiming to ensure the system operates efficiently under various conditions. However, the existing methods may not account for the dynamic conditions the system operates under. A significant limitation of existing charging methods may be their inability to account for the effect of environmental factors, particularly humidity, on the system's refrigerant requirements. The amount of refrigerant needed in the system, especially in the vapor line during cooling operations, may vary with the humidity levels in the environment. Lower humidity environments may necessitate less refrigerant compared to higher humidity conditions. This variation may be due to the impact of air moisture levels on the thermal properties and pressure of the refrigerant, affecting its efficiency in heat exchange processes.

Existing solutions do not consider the dynamic nature of the operating environment, leading to inefficiencies in system operation. Undercharging or overcharging the system may result in decreased efficiency, increased energy consumption, reduced comfort levels, and potentially, premature system failure. Thus, there is a need for an improved solution for charging residential split HVAC systems which dynamically accounts for environmental humidity, ensuring optimal system performance and efficiency.

This disclosure addresses these issues by providing a solution for optimizing the refrigerant charge in residential split HVAC systems based on real-time environmental humidity conditions. This approach allows for precise adjustment of the refrigerant charge, improving HVAC system's efficiency, performance, and longevity, while also reducing energy consumption and operational costs.

Referring to, a schematic representation of a refrigerant circuit of a HVAC unit is shown. Components of the HVAC unit may be partially placed on an indoor sideand/or partially placed on an outdoor side, with respect to an enclosure to be cooled or heated. It may be appreciated that the refrigerant circuit may include other components, which may be arranged differently that the representation shown in.

The refrigerant circuit may include a compressorconfigured to pump a refrigerant through conduits or channels of the refrigerant circuit. Pumping the refrigerant may raise the pressure of the refrigerant. The conduits may fluidically couple the compressorto a condenser.

The condensermay include outdoor coils configured to allow the refrigerant to reject heat to outdoor air on the outdoor side, which may cause the refrigerant to condense and/or liquify. The liquid refrigerant may then be flowed through another conduit (also referred to as ‘liquid line’) fluidically coupling the condenserto an expansion device.

The expansion devicemay be configured to expand and reduce the pressure of the refrigerant. Then, a further conduit between the configured to flow the expanded refrigerant from the expansion deviceto an evaporator.

The evaporatormay include indoor coils configured to facilitate transfer of heat from air in the indoor sideto the refrigerant. The refrigerant may vaporize as a result of the absorption of the heat from the indoor side. The vaporized refrigerant may be flowed from the evaporatorto the compressorthrough yet another conduit (also referred to as ‘vapor line’).

The refrigerant circuit may be charged with the refrigerant. Charging refers to adding or increasing amount of refrigerant in liquid state. The refrigerant circuit may be charged either by adding or increasing weight of the refrigerant, or by subcooling the refrigerant to a subcooling target temperature increase amount of liquid refrigerant.

The performance of the refrigerant circuit change based on operating environment of the HVAC unit. The operating environment may be affected by humidity, among other parameters. For instance, at low humidity, less refrigerant may be required in comparison to high humidity environment, for optimal performance. The refrigerant may need to be charged according to the operating environment for optimal performance.

The refrigerant circuit may include a devicefor determining charge setting of the refrigerant circuit, as shown in. The device may be communicatively coupled to the components of the refrigerant circuit, and one or more sensors (not shown) of the refrigerant circuit.

Referring to, the devicefor determining charge settings for a refrigeration circuit of the HVAC unit is disclosed. The devicemay include an input unitthat may enable users to select or enter an operating environment of the HVAC unit and/or an internal volume of a vapor line of the refrigeration circuit. The devicemay also be configured to receive the operating environment using a set of sensors (such as humidity sensors) communicatively coupled to the HVAC unit.

In one or more embodiments, the operating environment may be selected from one of, a humid condition, a semi-arid condition, and a desert condition. The humid condition may pertain to a first range of humidity, a semi-arid condition may pertain to a second range of humidity, and a desert condition may pertain to a third range of humidity, where the first range may be greater than the second range and the second range may be greater than the third range. In an example, the humid condition may pertain to a humidity level of 50% or higher, the semi-arid condition may pertain to a humidity level of 25 and 50%, and the desert condition may pertain to a humidity level below 25%. In other embodiments, the operating environment may be represented by continuous valves of humidity, among other parameters.

Further, the devicemay include a controllerthat may be in communication with or operatively connected to the input unit. The controllermay receive a set of data pertaining to the operating environment of the HVAC unit (being selected in the input unit) and/or an internal volume of a vapor line and a liquid line of the refrigeration circuit, from corresponding sensors. The controllermay accordingly estimate/determine a saturated suction temperature of a refrigerant in the refrigeration circuit based on the selected operating environment.

In one or more embodiments, the controllermay associate the first range of humidity with a refrigerant saturation temperature of 51° F., the second range of humidity with a refrigerant saturation temperature of 44° F., and the third range of humidity with a refrigerant saturation temperature of 37° F.

The estimated/determined saturated suction temperature may be indicative of the operating pressure of the refrigerant at the vapor line or the vapor density of the refrigerant in the vapor line.

In one or more embodiments, the controllermay further determine the weight/amount of the refrigerant to be allocated for the vapor line and the liquid line, and/or a subcooling target temperature for the liquid line based on the estimated saturated suction temperature and the internal volume of the refrigeration circuit.

In one or more embodiments, the controllermay be configured to transmit electronic control signals to one or more flow control devices to charge the refrigerant circuit.

In one or more embodiments, a service port on the refrigerant circuit (not shown) may be used to physically add refrigerant to the refrigerant circuit according to the determined weight/amount. In one or more embodiments, the controllermay be configured to transmit electronic control signals to the service port to open to allow more refrigerant to enter into the refrigerant circuit from a reservoir. The controllermay be configured to close the service port, once the determined weight/amount of refrigerant has been added to the refrigerant circuit. This may facilitate the users to feed an optimized amount of refrigerant into the refrigeration circuit through the service port, such that the added refrigerant may move through the refrigeration circuit and the allocated weight of the refrigerant may distribute itself in the vapor line and the liquid line.

In one or more embodiments, the controllermay be configured to transmit electronic control signals to change operation of the components of the refrigerant circuit. In one or more embodiments, the controllermay be configured to transmit electronic control signals to increase or decrease speed of outdoor fans, for example, to increase or decrease, respectively, subcooling temperature of the refrigerant to a subcooling target temperature determined based on the determined saturated suction temperature.

In one or more embodiments, the controllermay additionally receive another set of data pertaining to one or more of the internal volume of the evaporatorof the HVAC unit, configuration of the evaporator, and characteristics of the refrigerant. Accordingly, the controllermay determine the weight of the refrigerant to be allocated for the evaporatorbased on the received another set of data and the operating environment of the HVAC unit. Accordingly, an optimized amount of refrigerant may feed into the refrigeration circuit through the service port, such that the refrigerant may move through the refrigeration circuit and the allocated weight of the refrigerant may distribute itself in the evaporator.

In one or more embodiments, the input unitmay enable users to enter the internal volume of the refrigeration circuit, the internal volume of the vapor line and liquid line, the internal volume of the evaporator, the configuration of the evaporator, and/or characteristics (type) of the refrigerant being used into the controller. These inputs may then be stored in a database-associated with the controllerat the time of installation of the HVAC unit or at the time of charging the refrigeration circuit. Further, at the time of charging the refrigeration circuit, the users may select the operating environment, and the controllermay retrieve the stored data pertaining to the internal volume of the vapor line and liquid line, the internal volume of the evaporator, the configuration of the evaporator, and/or characteristics of the refrigerant from the database-, and correspondingly determine the weight of the refrigerant to be allocated for the vapor line and the liquid line, or the subcooling target temperature for the liquid line, and/or the weight of the refrigerant to be allocated for the evaporator.

In one or more embodiments, the input unitmay include one or more human-machine interfaces (HMIs), such as buttons, switches, knobs, keypads, touchscreens, levers, and the like, but not limited thereto. In one or more embodiments, the input unitmay include a touchscreen display device, a keyboard, and a set of buttons for different environmental conditions, but not limited to like.

In addition, the devicemay include an output unitoperatively connected to the controller. The controllermay enable the output unitto display the determined weight of the refrigerant to be added to the refrigeration circuit or the determined weight of the refrigerant to be allocated for the vapor line and the liquid line or the determined subcooling target temperature for the liquid line, and/or the weight of the refrigerant to be allocated for the evaporator.

In one or more embodiments, the output unitmay include a display or a monitor. The display may be configured to graphically display weight/amount of the refrigerant to be allocated for the vapor line and the liquid line, or the determined subcooling target temperature. Further, the output unitmay include a display device, and a speaker, but not limited to the like.

Further, in one or more embodiments, the devicemay include a humidity sensor (not shown) operatively coupled to or in communication with the controller. The humidity sensor may monitor specific humidity or relative humidity around the outdoor coil of the HVAC unit and transmit the monitored humidity data to the controller. Accordingly, the controllermay determine the operating environment of the HVAC unit based on the monitored humidity. This may enable an automated operating environment selection by the device, allowing the deviceto automatically determine and display the weight of the refrigerant to be added to refrigeration circuit or the subcooling target temperature for the liquid line, and/or the weight of the refrigerant to be allocated for the evaporator.