Patent Application
20250003624
This present application claims the benefit of India Provisional Application No. 202331044071, filed Jun. 30, 2023 entitled Compressor Discharge Temperature Control Via Electronic Expansion Valve, which is hereby incorporated by reference in its entirety.
The present disclosure relates generally to systems and methods for regulating the discharge temperature of refrigerant flowing through a discharge port of a compressor by modulating the position of an electronic expansion valve.
Various climate control systems exist, and several of these systems are able to provide both heating and cooling. These systems use refrigerant circuits to transport thermal energy between components of the system using thermal gradients. Each of these designs offer various advantages, and typically provide for conditioning over a given temperature range. A common form of these systems, often referred to as a heat pump, uses a reversible refrigerant circuit that moves thermal energy between two or more heat exchangers to provide heating and/or cooling as desired.
The refrigerant circuits of each of these systems are driven by a compressor that pulls in low temperature/pressure vapor and compresses the vapor to discharge high temperature/pressure gas. Each of these compressors are rated for a certain temperature range to deliver a rated capacity. Each of these systems is exposed to different environmental conditions that effect performance and place varied demands on the compressor to deliver heating capacity within a rated operating range. Operating in very low temperature environments can push a compressor's discharge temperature to the upper limits of its rated temperature operating range. These types of low temperature environments and limited operating ranges can lead to inadequate heating capacity and inefficient system performance. Operating a compressor reliably and efficiently to encompass very low temperature environments, however, can be challenging.
Some systems seek to increase heat pump capacity by adding larger compressors. These systems, however, may be oversized for most operations, which may result in poorer overall efficiency, excess cost, a larger footprint, and/or other issues. As a result, there exists an opportunity for an active approach to increase the operating performance of heat pump compressors down into lower temperature ranges.
The present disclosure includes, without limitation, the following examples.
Some example implementations include a climate control system comprising: a compressor including an inlet port and a discharge port; an evaporator fluidly coupled to the inlet port of the compressor; a modulating valve fluidly coupled to the evaporator and configured to control a flow of a refrigerant fluid delivered to the evaporator; and control circuitry communicatively coupled to the modulating valve, the control circuitry configured to at least: control the modulating valve according to a superheat setpoint; transfer control of the modulating valve from the superheat setpoint to a discharge temperature setpoint based, at least in part, on one or more conditions; and control the modulating valve according to the discharge temperature setpoint, including the control circuitry further configured to at least: receive a discharge temperature signal representing a temperature of a refrigerant fluid flowing through the discharge port of the compressor; compare the discharge temperature signal to the discharge temperature setpoint; determine a discharge temperature error based, at least in part, on the comparison; and adjust a position of the modulating valve based, at least in part, on reducing the discharge temperature error.
Further example implementations may include a method for controlling a modulating valve of a climate control system according to a discharge temperature setpoint, the method comprising: controlling the modulating valve according to a superheat setpoint; transferring control of the modulating valve from the superheat setpoint to a discharge temperature setpoint based, at least in part, on one or more conditions; and controlling the modulating valve according to the discharge temperature setpoint; receiving a discharge temperature signal representing a temperature of a refrigerant fluid flowing through a discharge port of a compressor; comparing the discharge temperature signal to the discharge temperature setpoint; determining a discharge temperature error based, at least in part, on the comparison; and adjusting a position of the modulating valve based, at least in part, on reducing the discharge temperature error.
Further example implementations may include a control circuit for a climate control system, the control circuit comprising: a memory configured to store executable program code; a processor configured to access the memory, and execute the executable program code to cause the control circuit to at least: access a superheat controller for controlling a modulating valve according to a superheat setpoint; access a switching controller for transferring control of the modulating valve from the superheat setpoint to a discharge temperature setpoint based, at least in part, on one or more conditions; and access a discharge temperature controller for controlling the modulating valve according to the discharge temperature setpoint, further causing the control circuit to at least: receive a discharge temperature signal representing a temperature of a refrigerant fluid flowing through a discharge port of a compressor; compare the discharge temperature signal to the discharge temperature setpoint; determine a discharge temperature error based, at least in part, on the comparison; and transmit a position signal representative of an adjustment to a position of the modulating valve based, at least in part, on reducing the discharge temperature error.
These and other features, aspects, and advantages of the disclosure will be apparent from a reading of the following detailed description together with the accompanying drawings, which are briefly described below. The disclosure includes any combination of two, three, four, or more of the above-noted embodiments, examples, or implementations as well as combinations of any two, three, four, or more features or elements set forth in this disclosure, regardless of whether such features or elements are expressly combined in a specific example description herein. This disclosure is intended to be read holistically such that any separable features or elements of the disclosed disclosure, in any of its various aspects, embodiments, examples, or implementations, should be viewed as intended to be combinable unless the context clearly dictates otherwise.
In order to assist the understanding of aspects of the disclosure, reference will now be made to the appended drawings, which are not necessarily drawn to scale. The drawings are provided by way of example to assist in the understanding of aspects of the disclosure, and should not be construed as limiting the disclosure.
Some implementations of the present disclosure will now be described more fully hereinafter with reference to the accompanying figures, in which some, but not all implementations of the disclosure are shown. Indeed, various implementations of the disclosure may be embodied in many different forms and should not be construed as limited to the embodiments, examples, or implementations set forth herein; rather, these embodiments, examples, or implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
For example, unless specified otherwise or clear from context, references to first, second or the like should not be construed to imply a particular order. A feature described as being above another feature (unless specified otherwise or clear from context) may instead be below, and vice versa; and similarly, features described as being to the left of another feature may instead be to the right, and vice versa. Also, while reference may be made herein to quantitative measures, values, geometric relationships or the like, unless otherwise stated, any one or more if not all of these may be absolute or approximate to account for acceptable variations that may occur, such as those due to engineering tolerances or the like. Additionally, when used herein (including in the claims), the words “about,” “generally,” “substantially,” “approximately,” and the like may mean within a range of plus or minus 10%.
As used herein, unless specified otherwise, or clear from context, the “or” of a set of operands is the “inclusive or” and thereby true if and only if one or more of the operands is true, as opposed to the “exclusive or” which is false when all of the operands are true. Thus, for example, “[A] or [B]” is true if [A] is true, or if [B] is true, or if both [A] and [B] are true. Further, the articles “a” and “an” mean “one or more,” unless specified otherwise or clear from context to be directed to a singular form. Like reference numerals refer to like elements throughout.
As used herein, the terms “bottom,” “top,” “upper,” “lower,” “upward,” “downward,” “rightward,” “leftward,” “interior,” “exterior,” and/or similar terms are used for ease of explanation and refer generally to the position of certain components or portions of the components of embodiments, examples, or implementations of the described disclosure in the installed configuration (e.g., in an operational configuration). It is understood that such terms are not used in any absolute sense.
Example implementations of the present disclosure relate to systems and methods for controlling the positioning of a modulating valve of a heat pump based, at least in part, on a discharge temperature setpoint of a compressor during periods of low ambient outdoor temperatures. In some examples, a climate control system may default to a superheat controller for controlling the positioning of the modulating valve based, at least in part, on a superheat setpoint and a superheat value. Upon detection of ambient outdoor temperatures below a minimum threshold and the detection of discharge temperatures of a compressor above a maximum threshold, the climate control system may switch control of the modulating valve from the superheat controller to a discharge temperature controller. In some examples, the discharge temperature controller may control the positioning of the modulating valve based, at least in part, on a discharge temperature setpoint and a map-based controller. In some examples, the map-based controller may map a calculated discharge temperature error to a position of the modulating valve as a function of a calculated superheat value and a measured suction pressure. An advantage of controlling a modulating valve based, at least in part, on a discharge temperature setpoint, or the like, is that the discharge temperature controller allows for reductions in enthalpy at the inlet port of the compressor. Further, the discharge temperature controller may allow the compressor to operate at full speed at lower ambient outdoor temperatures for longer periods of time relative to a superheat controller.
Before discussing the details of the process for controlling the modulating valve according to at least, in part, the discharge temperature setpoint, an overview of an example embodiment of a climate control system, and components thereof, is discussed with reference to
The compressor 104 may be a single-stage, a single speed, a two-stage, a variable speed, and/or variable capacity compressor that includes at least an inlet port 104a and a discharge port 104b as illustrated in
Moreover, as shown, the inlet port 104a of the compressor 104 may be communicatively coupled to at least a sensor 110a of the plurality of sensors 110a-110d. The sensor 110a may monitor a refrigerant fluid pressure and/or temperature of a refrigerant fluid proximate the sensor 110a, e.g., flowing into and/or through the inlet port 104a of the compressor 104. Additionally, the discharge port 104b of the compressor 104 may be communicatively coupled to at least a sensor 110b of the plurality of sensors 110a-110d. The sensor 110b may monitor a refrigerant fluid pressure and/or temperature of a refrigerant fluid proximate the sensor 110b, e.g., flowing through and/or out of the discharge port 104b of the compressor 104. In some examples, the sensor 110b may be positioned proximate the discharge port 104b, or at another position, of the compressor 104 in order to monitor a flow of refrigerant fluid most representative of a saturated discharge temperature (SDT), and/or the like, of the refrigerant fluid circuit 134. For example, the sensor 110b may be coupled to a housing, a shell, and/or a dome of the compressor 104. In some examples, the sensor 110b and/or other sensors (not shown) may be coupled within the interior of the compressor 104, e.g., to provide signals representative of saturated discharge temperature, a compressor speed, or a compressor pressure. In some examples, a housing temperature, a shell temperature, and/or a dome temperature of the compressor 104 may be representative of the saturated discharge temperature.
In some examples, the sensor 110a and/or the sensor 110b may transmit one or more signals representing a refrigerant fluid pressure and/or temperature to at least the control circuitry 112. In some examples, the control circuitry 112 may cause one or more sensors of the plurality of sensors 110a-110d to record and/or transmit one or more signals representative of a pressure and/or a temperature, e.g., of a refrigerant fluid, ambient outdoor environment, or the like.
The evaporator 102 may be a heat exchanger that is fluidly coupled to at least the inlet port 104a of the compressor 104 and the modulating valve 108. The evaporator 102 may be configured to receive a refrigerant fluid from the modulating valve 108 and convey the refrigerant fluid to at least the inlet port 104a of the compressor 104 as illustrated in
The modulating valve 108 may be an electric expansion valve (EEV), e.g., a stepper motor EEV, a pulse-width EEV, or the like, fluidly coupled to the evaporator 102 as illustrated in
In some examples, the amount of refrigerant fluid exiting the modulating valve 108 may be proportional to the amount of fluid flowing through the evaporator 102 and the compressor 104. In some examples, the amount of refrigerant fluid exiting the modulating valve 108 may be inversely proportional to an enthalpy at the inlet port 104a of the compressor 104 and/or the discharge temperature of the discharge port 104b of the compressor 104. In some examples, as the modulating valve 108 is opened to allow more refrigerant fluid through, the enthalpy at the inlet port 104a may decrease and/or the discharge temperature of the discharge port 104b may decrease. Additionally, as the modulating valve 108 is closed to allow less refrigerant fluid through, the enthalpy at the inlet port 104a may increase and/or the discharge temperature of the discharge port 104b may increase. In some examples, the modulating valve 108 may be opened and/or closed incrementally, e.g., in steps by a stepper motor of the modulating valve 108, in response to command signals received from the control circuitry 112.
Additionally, the modulating valve 108, or a control circuit thereof, may be configured to transmit information signals representative of a position of the modulating valve 108 to the control circuitry 112. For example, the modulating valve 108, or a control circuit thereof, may transmit a position signal representative of a position that the modulating valve 108 is opened/closed relative to, e.g., a position of a stepper motor, to the control circuitry 112. In some examples, the modulating valve 108 may be coupled to an intermediate control circuit that may be communicatively coupled to control circuitry 112. For example, the modulating valve 108 may be coupled to an indoor controller 524 which will be described in further detail below with respect to at least
The condenser 106 may be a heat exchanger that is fluidly coupled to at least the discharge port 104b of the compressor 104 and the modulating valve 108. The condenser 106 may be configured to receive a refrigerant fluid from the discharge port 104b of the compressor 104 and convey the refrigerant fluid to at least the modulating valve 108 as illustrated in
The control circuitry 112 may comprise in whole or in part the control circuitry 600 which will be described in further detail below with respect to at least
In some examples, the control circuitry 112 may perform one or more determinations, calculations, comparisons, and/or the like based at least, in part, on one or more received signals as will be described in further detail below. For example, the control circuitry 112 may determine when to control the modulating valve 108 based at least, in part, on the superheat controller 114 or the discharge temperature controller 118. In some examples, the determination to switch control between the superheat controller 114 and the discharge temperature controller 118 may be based at least, in part, on the switching controller 116 and one or more received signals. As shown in
As discussed above, the systems and methods described herein may utilize different example control circuitry and controller algorithms to, at least in part, control the modulating valve and/or compressor of the climate control system under various different conditions. Various different configurations and other non-limiting examples of the control circuitry and controller algorithms will now be walked through in further detail below with reference to
Turning to
To further walk through the process of transferring control of a climate control system between a superheat controller and a discharge temperature controller, each of operations 202-214 described above will now be discussed in more detail with further reference to
As shown at operation 202, the control transfer process 200 begins with receipt of a startup signal representative of a command to start the climate control system. In some examples, this may include turning on the climate control system from an off or idle state and/or switching the climate control system into a heating mode and/or another mode. This may also include restarting the climate control system or at least, in part, a component thereof, e.g., the modulating valve, compressor, or the like. This may include the control circuitry of the climate control system receiving a request signal representing a request to initially provide, or increase, a delivered capacity of the climate control system. In some examples, the request signal may be representative of a request for heating capacity and may be provided from a thermostat to a system controller, and/or other control circuitry, of the climate control system. In some examples, the request signal may be further representative of a request for one or more of a heating mode, a cooling, mode, an increase in conditioning capacity, a decrease in conditioning capacity, or the like.
As shown at operation 204, the process 200 initially controls the climate control system with a superheat controller, e.g., upon startup of the climate control system. In some examples, the superheat controller may comprise at least partially a controller algorithm, executable program code, or the like, and may be stored, at least in part, on the control circuitry of a climate control system. The superheat controller may provide, at least in part, instructions for the control circuitry to control a modulating valve of the climate control system to maintain a superheat setpoint. In some examples, the superheat setpoint may be predefined according to the model of the climate control system and/or a type of refrigerant fluid utilized by the climate control system. In some examples, the superheat setpoint may be maintained to within a superheat setpoint offset value from the superheat setpoint. For example, the superheat setpoint may be defined as 10° F. and the superheat setpoint offset value may be defined as ±1° F., thus the superheat controller would control the modulating valve to maintain a superheat of 10±1° F.
In some examples, the control circuitry may calculate the superheat of the climate control system by calculating a difference between a suction temperature, e.g., at the inlet port 104a of the compressor 104, and the saturated suction temperature, e.g., at the outlet 102a of the evaporator 102. The control circuitry may receive signals representative of the suction temperature and the saturated suction temperature, e.g., from the plurality of sensors 110a-110d, to utilize for the superheat calculations. In some examples, the operation 204 may further include receiving a saturated suction temperature signal representing a saturated suction temperature of the refrigerant fluid flowing through the evaporator, e.g., from, at least in part, the sensor 110c. In some examples, the operation 204 may further include receiving a suction temperature signal representing a suction temperature of the refrigerant fluid flowing through the inlet port of the compressor, e.g., from, at least in part, the sensor 110a. In some examples, the operation 204 may further include determining a superheat value based, at least in part, on a difference between the saturated suction temperature signal from sensor 110c and a suction temperature signal from sensor 110a. In some examples, the operation 204 may further include adjusting the position of the modulating valve based, at least in part, on reducing the superheat value toward the superheat setpoint. In some examples, the suction pressure may, at least in part, replace the saturated suction temperature to calculate the superheat value as described above. In such examples, the saturated suction temperature may be determined from the suction pressure and the refrigerant fluid type.
As shown at operation 206, the process 200 monitors, e.g., via one or more sensors, a saturated discharge temperature, depicted as “SDT,” of the climate control system to determine if the saturated discharge temperature is greater than a discharge temperature threshold while utilizing the superheat controller. In some examples, the discharge temperature threshold may be defined at 205° F. In some examples, other values may be used for the discharge temperature threshold, e.g., 80° F.-220° F. or the like. As shown at operation 206, the control circuitry may determine that the saturated discharge temperature is less than the discharge temperature threshold and the control circuitry may continue to utilize the superheat controller as described above at operation 204. Alternatively, the control circuitry may determine that the saturated discharge temperature is greater than the discharge temperature threshold and the process 200 may continue to operation 208. In some examples, the operation 206 may further include commanding the one or more sensors, e.g., sensor 110b and/or the like, to transmit a signal representative of the saturated discharge temperature and/or the like. Additionally, the operation 206 may further include receiving a signal representative of the saturated discharge temperature and/or the like, e.g., from sensor 110b and/or the like.
As shown at operation 208, the process 200 monitors an ambient outdoor temperature, depicted as “Amb. ODT,” of the climate control system to determine if the ambient outdoor temperature is less than an ambient outdoor temperature threshold while utilizing the superheat controller. In some examples, operation 208 may be performed before operation 206. In some examples, operation 206 and operation 208 may be performed simultaneously or at substantially the same time. In some examples, the ambient outdoor temperature threshold may be defined at 17° F. In some examples, other values may be used for the discharge temperature threshold, e.g., 15° F.-20° F. or the like. As shown at operation 208, the control circuitry may determine that the ambient outdoor temperature is greater than the ambient outdoor temperature threshold and the control circuitry may continue to utilize the superheat controller as described above at operation 204. Alternatively, the control circuitry may determine that the ambient outdoor temperature is less than the ambient outdoor temperature threshold and the process 200 may continue to operation 210. In some examples, the operation 208 may further include commanding the one or more sensors, e.g., sensor 110d and/or the like, to transmit a signal representative of the ambient outdoor temperature and/or the like. Additionally, the operation 208 may further include receiving a signal representative of the ambient outdoor temperature and/or the like, e.g., from sensor 110d and/or the like.
As shown at operation 210, the process 200 switches control of the climate control system from the superheat controller to a discharge temperature controller. The discharge temperature controller may control the modulating valve of the climate control system to at least, in part, maintain a discharge temperature setpoint. In some examples, the discharge temperature controller may comprise at least partially a controller algorithm, executable program code, or the like, and may be stored, at least in part, on the control circuitry of a climate control system. The discharge temperature controller may provide, at least in part, instructions for the control circuitry to control a modulating valve of the climate control system to maintain a discharge temperature setpoint. In some examples, the discharge temperature setpoint may be predefined according to the model of the climate control system and/or a type of refrigerant fluid utilized by the climate control system.
In some examples, the discharge temperature setpoint may be maintained to within a discharge temperature setpoint offset value from the discharge temperature setpoint. For example, the discharge temperature setpoint may be defined as 195° F. and the discharge temperature setpoint offset value may be defined as ±3° F., thus the discharge temperature controller would control the modulating valve to reach and/or maintain a discharge temperature of 195±3° F., e.g., for a period of time. In some examples, the discharge temperature setpoint may not include a discharge temperature setpoint offset value, e.g., no discharge temperature setpoint offset value may be defined. In other examples, the discharge temperature setpoint offset value may be ±0° F. In such examples, the discharge temperature setpoint offset value may be dynamically adjusted from ±0° F. to another value and/or range of values. For example, the discharge temperature setpoint offset value may be initially defined as ±0° F. and may be adjusted based, at least in part, on one or more conditions as described herein, to a range of −10° F. to +5° F. In some examples, the discharge temperature setpoint offset value may be dynamically adjusted based, at least in part, on the performance of the controller to reach and/or maintain a discharge temperature setpoint, e.g., without a need to switch between controllers for a predetermined period of time. It should be understood that the discharge temperature setpoint may be predetermined based, at least in part, on a requirement to reduce the enthalpy of a portion of the refrigerant fluid flowing through the discharge port of the compressor. Still further examples of the operation 210 may comprise at least, in part, the process 300 as will be described in further detail below with reference to
As shown at operation 212, the process 200 monitors the ambient outdoor temperature of the climate control system to determine if the ambient outdoor temperature is less than an ambient outdoor temperature threshold while utilizing the discharge temperature controller. In some examples, operation 212 may be performed after operation 214. In some examples, operation 212 and operation 214 may be performed simultaneously or at substantially the same time. In some examples, operation 212 may utilize the ambient outdoor temperature threshold defined at operation 208 above. In other examples, the ambient outdoor temperature threshold defined at operation 212 may be different from the ambient outdoor temperature threshold defined at operation 208 above. In some examples, the processes performed at operation 212 may be the same or substantially similar to the processes described above with respect to operation 208. As shown at operation 212, the control circuitry may determine that the ambient outdoor temperature is greater than the ambient outdoor temperature threshold and the control circuitry may switch to the superheat controller as described above at operation 204. Alternatively, the control circuitry may determine that the ambient outdoor temperature is less than the ambient outdoor temperature threshold and the process 200 may continue to operation 214.
As shown at operation 214, the process 200 monitors the saturated discharge temperature of the climate control system to determine if the saturated discharge temperature is less than a discharge temperature setpoint while utilizing the discharge temperature controller. In some examples, operation 214 may utilize the discharge temperature setpoint defined at operation 210 above, e.g., the discharge temperature setpoint may be defined at 195° F. As shown at operation 214, the control circuitry may determine that the saturated discharge temperature is not less than the discharge temperature setpoint, e.g., by at least a discharge temperature setpoint offset value of 10° F. or another value, and the control circuitry may continue to utilize the discharge temperature controller as described above at operation 210. Alternatively, the control circuitry may determine that the saturated discharge temperature is less than the discharge temperature setpoint and the control circuitry may switch to the superheat controller as described above at operation 204. In some examples, the operation 214 may further include commanding the one or more sensors, e.g., sensor 110b and/or the like, to transmit a signal representative of the saturated discharge temperature and/or the like. Additionally, the operation 214 may further include receiving a signal representative of the saturated discharge temperature and/or the like, e.g., from sensor 110b and/or the like.
It should be appreciated that the superheat controller may be preferred for controlling the climate control system in heating mode when the ambient outdoor temperature may be relatively warm, e.g., above 17° F. or the like, because the relatively warm ambient outdoor air can more efficiently transfer thermal energy to the refrigerant fluid thus requiring less capacity from the compressor, e.g., allowing the compressor to operate at, or below, its full speed. Moreover, switching to the discharge temperature controller may be preferred for controlling the climate control system in heating mode when the ambient outdoor temperature is relatively cold, e.g., equal to or below 17° F.
At these relatively cold temperatures the superheat controller may require more capacity from the compressor than the compressor can provide, e.g., while maintaining the necessary superheat value of the superheat controller. However, the discharge temperature controller may adjust the modulating valve at these relatively cold temperatures to deliver more refrigerant fluid to the inlet port of the compressor, e.g., resulting in lower enthalpy of the portion of the refrigerant fluid flowing through the discharge port of the compressor. It should be appreciated that while the overall enthalpy of the refrigerant fluid flowing through the discharge port of the compressor may decrease, the climate control system can increase the volume of refrigerant fluid and maintain the compressor's full speed with the discharge temperature controller resulting in an overall increase in heat pump capacity at relatively cold temperatures, e.g., when compared to the superheat controller.
Now that the process 200 for transferring control of a climate control system between a superheat controller and a discharge temperature controller has been described in detail above with respect to
Turning to
To further walk through the process 300 for controlling the modulating valve based, at least in part, on a discharge temperature setpoint, each of operations 302-320 described above will now be discussed in more detail with further reference to
As shown at operation 302, the process 300 begins at operation 302 with receipt of a discharge temperature setpoint. As depicted, the discharge temperature setpoint includes a saturated discharge temperature (SDT) setpoint. However, in other examples, the discharge temperature setpoint may be a value representative of a desired change in a saturated discharge temperature and/or the like. In some examples, the discharge temperature setpoint may include one or more of a housing temperature setpoint of a compressor, a shell temperature setpoint of a compressor, a dome temperature setpoint of a compressor, or the like. In some examples, the discharge temperature setpoint may be a predefined value based on a model of the climate control system and/or a refrigerant fluid type. In some examples, the discharge temperature setpoint may be defined based on environmental conditions at the installation site of the climate control system, e.g., by a dealer, technician, or the like. In some examples, the discharge temperature setpoint may be defined as 195° F. or another defined temperature value. In other examples, the discharge temperature setpoint may be defined in relation to the discharge temperature threshold. For example, the discharge temperature setpoint may be 10° F., or another discharge temperature threshold offset value, less than the discharge temperature threshold. In other examples, the discharge temperature setpoint may be defined by an algorithm based, at least in part, on one or more sensor measurements. For example, the discharge temperature setpoint may be defined by an algorithm based on a sensor measurement representative of a discharge pressure, a discharge superheat, and/or other measurable refrigerant fluid characteristics as described herein.
As shown at operation 304, the process 300 compares the discharge temperature signal representative of a discharge temperature with the discharge temperature setpoint to determine a discharge temperature error. In some examples, the discharge temperature error may be representative of a change in the discharge temperature. For example, the discharge temperature setpoint may be 195° F. and the discharge temperature signal may represent a discharge temperature of 199° F. Thus, the resulting example discharge temperature error would indicate that the measured discharge temperature is 4° F. from the discharge temperature setpoint.
As shown at operation 306, the process 300 transmits a discharge temperature error signal, e.g., at least in part to the map-based controller and/or other controllers described below. As depicted, the discharge temperature error includes a saturated discharge temperature (SDT) error. However, in other examples, the discharge temperature error may be a value representative of a predicted change in the saturated discharge temperature and/or the like. In some examples, the discharge temperature error may include one or more of a housing temperature error of a compressor, a shell temperature error of a compressor, a dome temperature error of a compressor, or the like.
As shown at operation 308, the process 300 receives at a map-based controller at least the discharge temperature error signal, a superheat value signal, and a suction pressure signal. The map-based controller may include a pre-populated map that correlates a change in a position of a modulating valve and, at least in part, the discharge temperature error. Further, the position of a modulating valve may be mapped to the discharge temperature error as a function of the suction pressure signal and the superheat value signal. For example, the map-based controller may correlate the discharge temperature error to a change in the suction pressure signal, e.g., when compared to a nominal and/or previously received suction pressure signal and/or a suction pressure setpoint, to determine a change in suction pressure, e.g., a desired change in the suction pressure that if applied will, at least in part, reduce the discharge temperature error, or the like. Further, the map-based controller may correlate the desired change in suction pressure to a change in the position of the modulating valve to determine and/or output an adjustment value to adjust the position of the modulating valve, e.g., to cause the desired change in suction pressure of the refrigerant fluid flowing through the inlet port of the compressor.
Moreover, the map-based controller may perform one or more iterations and store a record of one or more of the adjustments for the position of the modulating valve. In some examples, the map-based controller may predict one or more upcoming changes in the suction pressure signal to determine an adjustment for the position of the modulating valve, e.g., a single and/or final adjustment that will be sufficient to reach and/or exceed conditions for the discharge temperature setpoint. For example, a single and/or final adjustment may be correlated to, at least in part, a single and/or final desired change in the suction pressure signal. The single and/or final desired change in the suction pressure signal may be determined from a difference between the desired change in the suction pressure and the next predicted upcoming change in suction pressure due to the previously stored record of one or more of the adjustments made to the position of the modulating valve. In some examples, a record of one or more of the adjustments made to the position of the modulating valve correlating to one or more desired changes in the suction pressure may be preconfigured with the map-based controller. For example, the map-based controller may be configured with laboratory testing data or aggregate data collected from other climate control systems, e.g., at the time of installation. In some examples, the map-based controller may store historical data collected for the climate control system, e.g., as the process 300 or the like is executed over a period of time such as the start of the process 300, execution of an operation of process 300, and/or since installation of the system. Still additional inputs and processes may be utilized as described in further detail below.
As shown at operation 310, the process 300 transmits a valve position signal to, at least in part, the modulating valve and/or a control circuitry thereof. In some examples, the valve position signal may include an adjustment value for the position of the modulating valve, e.g., to cause the desired change in suction pressure of the refrigerant fluid flowing through the inlet port of the compressor and/or to reduce the discharge temperature of the refrigerant fluid flowing through the discharge port of the compressor. In some examples, the valve position signal may include a relative adjustment value for the modulating valve to be adjusted by, e.g., ±10 steps from the current position of a stepper motor. In some examples, the valve position signal may include an absolute adjustment value for the modulating valve, e.g., from a nominal or baseline position of the modulating valve, e.g., fully closed and/or fully opened. In some examples, the valve position signal may include one or more commands to adjust the modulating valve based on an adjustment value, e.g., make the adjustment all at once or incrementally.
As shown at operation 312, the process 300 adjusts the position of the modulating valve based, at least in part, on the valve position signal. In some examples, the modulating valve may be adjusted by control circuitry communicatively coupled to a stepper motor of the modulating valve. In some examples, adjusting the position of the modulating valve may include, at least in part, increasing or decreasing an opening within the modulating valve, e.g., to allow more or less refrigerant fluid to flow through the modulating valve.
As shown at operation 314, the process 300 commands one or more sensors to take one or more measurements and to transmit one or more signals representative of the one or more measurements. For example, the control circuitry may command one or more temperature sensors to transmit one or more signals representative of the saturated suction temperature at the evaporator, the suction temperature at the compressor, and/or the saturated discharge temperature at the compressor. Additionally, the control circuitry may command a pressure sensor to transmit a signal representative of the suction pressure at the compressor. Operation 314 may further include receiving, e.g., by the control circuitry, one or more of the signals representative of one or more of the measurements and utilize the one or more signals as described herein for process 300 and/or the like.
As shown at operation 316, the process 300 transmits a discharge temperature signal representative of a discharge temperature, e.g., at the discharge port of the compressor or the like. As depicted, the discharge temperature signal may include a saturated discharge temperature (SDT) signal representative of a SDT, e.g., for refrigerant fluid flowing through the discharge port of the compressor. In some examples, the discharge temperature signal may include one or more of a housing temperature of a compressor, a shell temperature of a compressor, a dome temperature of a compressor, or the like. In some examples, the discharge temperature signal may be utilized to perform another iteration of process 300, or the like, e.g., perform another comparison as described above for operation 304.
As shown at operation 318, the process 300 calculates a superheat value based, at least in part, on one or more signals representative of the saturated suction temperature at the evaporator and the suction temperature at the compressor. In some examples, the superheat value may be calculated as a difference between the suction temperature and the saturated suction temperature. In some examples, operation 318 may further include determining a refrigerant type, e.g., R-22, R-410A, R-32, R-134a, etc., representative of the refrigerant fluid, or properties thereof, flowing with in the climate control system. In some examples, the refrigerant type may be predefined, e.g., during charging of the climate control system by a technician. In some examples, the superheat value may be calculated based, at least in part, on the refrigerant type, the suction pressure, and/or the saturated suction temperature.
As shown at operation 319, the process 300 transmits a superheat value signal representative of a superheat value, e.g., of the refrigerant fluid flowing from the evaporator to the compressor. In some examples, the superheat value signal may be utilized to perform another iteration of process 300, or the like, e.g., perform, at least in part, another set of the processes as described above for operation 308.
As shown at operation 320, the process 300 transmits a suction pressure signal representative of a suction pressure, e.g., of the refrigerant fluid flowing through the inlet port of the compressor. In some examples, the suction pressure signal may be utilized to perform another iteration of process 300, or the like, e.g., perform, at least in part, another set of the processes as described above for operation 308.
Now that the process 200 for transferring control of a climate control system between a superheat controller and a discharge temperature controller have been described in detail above with respect to
Referring first to the example provided in
To further walk through the process of controlling, at least in part, a climate control system, each of operations 402-414 described above will now be discussed in more detail with further reference to
As shown at operation 402, the modulating valve control process 400 controls the modulating valve according to a superheat setpoint. This may include operating the climate control system in a heating mode and a request signal may be received, at operation 402, representative of a request for a heating capacity. In some examples, operation 402 may further include receiving a request signal representing a request to increase a delivered capacity of the climate control system, e.g., an increased heating demand provided by a user via a thermostat. In some examples, operation 402 may further include starting the climate control system and automatically defaulting control of the modulating valve to a superheat controller that controls the modulating valve according to a superheat setpoint. In such examples, the operation 402 may further include receiving a saturated suction temperature signal representing a saturated suction temperature of the refrigerant fluid flowing through the evaporator. Further, the operation 402 may also include receiving a suction temperature signal representing a suction temperature of the refrigerant fluid flowing through the inlet port of the compressor. Furthermore, the operation 402 may also include determining a superheat value based, at least in part, on a difference between the saturated suction temperature signal and the suction temperature signal. Moreover, the operation 402 may also include adjusting the position of the modulating valve based, at least in part, on reducing the superheat value toward the superheat setpoint.
As shown at operation 404, control of the modulating valve may be transferred from the superheat setpoint to a discharge temperature setpoint based, at least in part, on one or more conditions. The one or more conditions that may cause switching from the superheat controller to the discharge temperature controller may include one or more of an ambient outdoor temperature threshold, a discharge temperature threshold, a discharge temperature setpoint, a compressor safety threshold, or the like. In some examples, the one or more conditions may include a determination that the climate control system completed one or more startup operations with the superheat controller and/or that the climate control system has finished one or more defrost recovery operations. In some examples, the discharge temperature setpoint may be predetermined based, at least in part, on a requirement to reduce an enthalpy of a portion of the refrigerant fluid flowing through the discharge port of the compressor.
In some examples, the control of the modulating valve may not be transferred from the superheat setpoint to a discharge temperature setpoint when the discharge temperature setpoint exceeds the discharge temperature threshold unless other conditions are also met, e.g., the ambient outdoor temperature drops below the ambient outdoor temperature threshold, the compressor safety threshold is exceeded, or the like. For example, the climate control system may receive a request signal representative of a request, e.g., from a system controller or a user via a thermostat, to increase a delivered capacity of the climate control system, e.g., an increased demand for heating capacity delivered to a conditioned space. The increase in the delivered capacity may, in some examples, cause an increase in the enthalpy of, at least, a portion of the refrigerant fluid flowing through the discharge port of the compressor. As a result, the temperature at the discharge port may increase above a compressor safety threshold, e.g., set equal to or about 220° F., then the climate control system may decrease a speed of the compressor based, at least in part, on a compressor safety threshold. As a result, in some examples, the control circuitry may determine to control the modulating valve according to the discharge temperature setpoint in order to increase the flow of the refrigerant fluid delivered to the evaporator and thereby reduce the enthalpy of, at least, a portion of the refrigerant fluid flowing through the discharge port of the compressor. In some examples, a shutdown threshold may be set at some temperature above the compressor safety threshold to cause the climate control system or a component thereof to cease operation. For example, if the discharge temperature continues to increase further above the compressor safety threshold, e.g., after decreasing a speed of the compressor and/or transferring control to the discharge temperature controller, the climate control system or component thereof may shutdown, at least in part, the climate control system, e.g., to prevent damage to the system or the like.
Turning now to
Still with reference to
Referring back to
In some examples, the operation 406 may further include one or more of operations 408-414 as depicted in
Turning next to operation 408, the process 400 may include receiving a discharge temperature signal representing a temperature of a refrigerant fluid flowing through the discharge port of the compressor. The discharge temperature signal may be transmitted from a sensor located proximate the discharge port of the compressor and the sensor may be located at least partially within a housing of an outdoor unit of the climate control system. In some examples, the discharge temperature signal may be received from a sensor proximate other locations about the compressor, e.g., the dome of the compressor or the like as described above, to determine a discharge temperature at the discharge port of the compressor.
Turning next to operation 410, the process 400 may include comparing the discharge temperature signal to the discharge temperature setpoint. In some examples, the operation 410 may further include calculating a difference between the discharge temperature signal to the discharge temperature setpoint. Still other comparisons may be made between the discharge temperature signal and the discharge temperature setpoint.
Turning next to operation 412, the process 400 may include determining a discharge temperature error based, at least in part, on the comparison. In some examples, the discharge temperature error may be representative of a change in the discharge temperature. In some examples, the discharge temperature error may be a difference between the discharge temperature signal to the discharge temperature setpoint.
Turning next to operation 414, the process 400 may include adjusting a position of the modulating valve based, at least in part, on reducing the discharge temperature error. In some examples, the adjustment required for reducing the discharge temperature error made to the position of the modulating valve may be based on a pre-populated map between a change in the position of the modulating valve correlating to a change in a suction pressure of the refrigerant fluid flowing through the inlet port of the compressor. In some examples, the pre-populated map may be included as part of a map-based controller as described above for the process 300 at operation 308.
Turning now to
Still with reference to
In some examples, the operation 434 may further include comparing the superheat value to one or more conditions, e.g., a superheat value threshold, a timer, and/or the like. In some examples, the operation 434 may further include determining to transfer control of the modulating valve to the superheat controller based, at least in part, on the comparison of the superheat value to one or more conditions. For example, if the superheat value is equal to or greater than, e.g., 15° F., for at least a period of time, e.g., of 5 minutes, and/or the discharge temperature stays equal to or less than the discharge temperature setpoint, then the switching control may transfer control of the modulating valve back to the superheat controller. Still other values may be used for at least the superheat value threshold and/or the timer.
Turning now to
To further walk through the operation 414 as described above with respect to at least
Further, additional adjustments may be made to the position of the modulating valve over time. Each of the one or more adjustments to the position of the modulating valve may be recorded, e.g., as historical data. In some examples, the one or more adjustments to the position of the modulating valve may be combined to represent a total adjustment to the position of the modulating valve, e.g., made over a period of time such as since the process 400, or an operation thereof, was initiated. Then, based, at least in part, on the one or more adjustments to the position of the modulating valve a predicted change in the suction pressure signal may be calculated, e.g., using the pre-populated map between the change in the position of the modulating valve and the change in the suction pressure described above. It should be understood that there may be a time delay between when the one or more adjustments are made to the position of the modulating valve and when an updated suction pressure signal reflects these adjustments.
Furthermore, a predicted change in the suction pressure signal may be calculated before an updated suction pressure signal reflecting the one or more previously made adjustments to the position of the modulating valve is received, e.g., by the control circuitry. In some examples, calculating a predicted change in the suction pressure signal may further include calculating a predicted time at which the predicted change in the suction pressure signal is to be received. Therefore, if we return to the example desired change of suction pressure of 20 psi discussed above and the predicted change in the suction pressure signal, for example, is calculated to about 5 psi after another 45 seconds. Then, in such an example, the control circuitry may determine that an additional change in the position of the modulating valve may be, for example, about 15 steps in order to produce an additional change in the suction pressure of about 15 psi.
Indoor unit 502 generally comprises an indoor air handling unit comprising an indoor heat exchanger 508, an indoor fan 510, an indoor metering device 512, and an indoor controller 524. The indoor heat exchanger 508 may generally be configured to promote heat exchange between a refrigerant fluid carried within internal tubing of the indoor heat exchanger 508 and an airflow that may contact the indoor heat exchanger 508 but that is segregated from the refrigerant fluid. Indoor unit 502 may at least partially include, or be coupled to, a duct system 532 including one or more of an air return duct, a supply duct, a register, a vent, a damper, an air filter, or the like for providing airflow.
The indoor metering device 512 may generally comprise an electronically-controlled motor-driven electronic expansion valve (EEV). In some examples, however, the indoor metering device 512 may comprise a thermostatic expansion valve, a capillary tube assembly, and/or any other suitable metering device.
Outdoor unit 504 generally comprises an outdoor heat exchanger 514, a compressor 516, an outdoor fan 518, an outdoor metering device 520, a switch over valve 522, and an outdoor controller 526. The compressor 516 may be any type of compressor, including a compressor the same or similar to compressors discussed above. The outdoor heat exchanger 514 may generally be configured to promote heat transfer between a refrigerant fluid carried within internal passages of the outdoor heat exchanger 514 and an airflow that contacts the outdoor heat exchanger 514 but is segregated from the refrigerant fluid.
The outdoor metering device 520 may generally comprise a thermostatic expansion valve. In some examples, however, the outdoor metering device 520 may comprise an electronically-controlled motor driven EEV similar to indoor metering device 512, a capillary tube assembly, and/or any other suitable metering device.
In some examples, the switch over valve 522 may generally comprise a four-way reversing valve. The switch over valve 522 may also comprise an electrical solenoid, relay, and/or other device configured to selectively move a component of the switch over valve 522 between operational positions to alter the flow path of refrigerant fluid through the switch over valve 522 and consequently the climate control system 500. Additionally, the switch over valve 522 may also be selectively controlled by the system controller 506, an outdoor controller 526, and/or the indoor controller 524.
The system controller 506 may generally be configured to selectively communicate with the indoor controller 524 of the indoor unit 502, the outdoor controller 526 of the outdoor unit 504, and/or other components of the climate control system 500. In some examples, the system controller 506 may be configured to control operation of the indoor unit 502, and/or the outdoor unit 504. In some examples, the system controller 506 may be configured to monitor and/or communicate with a plurality of temperature and pressure sensors associated with components of the indoor unit 502, the outdoor unit 504, and/or the outdoor ambient environment.
Additionally, in some examples, the system controller 506 may comprise a temperature sensor and/or may further be configured to control heating and/or cooling of conditioned spaces or zones associated with the climate control system 500. In some examples, the system controller 506 may be configured as a thermostat for controlling the supply of conditioned air to zones associated with the climate control system 500, and in some examples, the thermostat includes a temperature sensor.
The system controller 506 may also generally comprise an input/output (I/O) unit (e.g., a graphical user interface, a touchscreen interface, or the like) for displaying information and for receiving user inputs. The system controller 506 may display information related to the operation of the climate control system 500 and may receive user inputs related to operation of the climate control system 500. However, the system controller 506 may further be operable to display information and receive user inputs tangentially related and/or unrelated to operation of the climate control system 500. In some examples, the system controller 506 may not comprise a display and may derive all information from inputs that come from remote sensors and remote configuration tools.
In some examples, the system controller 506 may be configured for selective bidirectional communication over a communication bus 528, which may utilize any type of communication network. For example, the communication may be via wired or wireless data links directly or across one or more networks, such as a control network. Examples of suitable communication protocols for the control network include CAN, TCP/IP, BACnet, LonTalk, Modbus, ZigBee, Zwave, Wi-Fi, SIMPLE, Bluetooth, and the like.
The indoor controller 524 may be carried by the indoor unit 502 and may generally be configured to receive information inputs, transmit information outputs, and/or otherwise communicate with the system controller 506, the outdoor controller 526, and/or any other device 530 via the communication bus 528 and/or any other suitable medium of communication. In some examples, the device 530 may include some or all of the systems described by the present disclosure. For example, the device 530 may be a sensor, or the like, as described by the present disclosure. In some examples, the device 530 may be housed within at least a unit (e.g., 502, 504, etc.) of the climate control system 500 and/or coupled thereto. In some examples, the device 530 may be a plurality of devices, each device 530 being associated with one or more units of the climate control system 500.
The outdoor controller 526 may be carried by the outdoor unit 504 and may be configured to receive information inputs from the system controller 506, which may be a thermostat. In some examples, the outdoor controller 526 may be configured to receive information related to an ambient temperature associated with the outdoor unit 504, information related to a temperature of the outdoor heat exchanger 514, and/or information related to refrigerant temperatures and/or pressures of refrigerant entering, exiting, and/or within the outdoor heat exchanger 514 and/or the compressor 516.
The processor 602 may be configured to access and/or execute computer programs such as computer-readable program code 606, which may be stored onboard the processor or otherwise stored in the memory 604. In some examples, the processor may be embodied as, or otherwise include, one or more ASICs, FPGAs or the like. Thus, although the processor may be capable of executing a computer program to perform one or more functions, the processor of various examples may be capable of performing one or more functions without the aid of a computer program.
The memory 604 is generally any piece of computer hardware capable of storing information such as, for example, data, computer-readable program code 606 or other computer programs, and/or other suitable information either on a temporary basis and/or a permanent basis. The memory may include volatile memory such as random access memory (RAM), and/or non-volatile memory such as a hard drive, flash memory or the like. In various instances, the memory may be referred to as a computer-readable storage medium, which is a non-transitory device capable of storing information. In some examples, then, the computer-readable storage medium is non-transitory and has computer-readable program code stored therein that, in response to execution by the processor 602, causes the control circuitry 600 to perform various operations as described herein, some of which may in turn cause the climate control system to perform various operations.
In addition to the memory 604, the processor 602 may also be connected to one or more peripherals such as a network adapter 608, one or more input/output (I/O) devices (e.g., input device(s) 610, output device(s) 612) or the like. The network adapter is a hardware component configured to connect the control circuitry 600 to a computer network to enable the control circuitry to transmit and/or receive information via the computer network. The I/O devices may include one or more input devices capable of receiving data or instructions for the control circuitry, and/or one or more output devices capable of providing an output from the control circuitry. Examples of suitable input devices include a keyboard, keypad or the like, and examples of suitable output devices include a display device such as a one or more light-emitting diodes (LEDs), a LED display, a liquid crystal display (LCD), or the like.
As explained above and reiterated below, the present disclosure includes, without limitation, the following example implementations.
Many modifications, other embodiments, examples, or implementations of the disclosure set forth herein will come to mind to one skilled in the art to which the disclosure pertains having the benefit of the teachings presented in the foregoing description and the associated figures. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments, examples, or implementations disclosed and that modifications and other embodiments, examples, or implementations are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated figures describe embodiments, examples, or implementations in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments, examples, or implementations without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202331044071 | Jun 2023 | IN | national |
