Description:FORM – 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10, Rule 13]

METHOD AND DEVICE FOR DELIVERING CONSISTENT AIRFLOW AGAINST INTERNAL AND EXTERNAL STATIC PRESSURE

BLUE STAR LIMITED A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS BLUE STAR LIMITED, BLUE STAR INNOVATION CENTRE, NEXT TO VIHANG’S INN HOTEL, KAPURBAVDI, GHODBUNDER ROAD, THANE WEST – 400 607, MAHARASHTRA, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.


TECHNICAL FIELD
The present disclosure relates generally to an air conditioning system. The present disclosure more particularly relates to delivering consistent airflow against variable internal and external static pressure in a ducted indoor air conditioning system.
BACKGROUND
A traditional ducted air conditioning system consists of an indoor unit and an outdoor unit that is used for comfort cooling in a defined space (refer figure 2 which represents indoor ducted room air conditioner unit).
In the context of ducted air conditioning systems, ducts serve as critical components that transport conditioned air from the indoor unit to various areas of a building or a defined space. In the case of standard ducted split air conditioners, indoor units are typically connected to ducts of varying lengths, as illustrated in figure 1. However, when duct lengths deviate significantly from the standard design, it can lead to performance issues and energy inefficiencies.
Excessive duct length can result in an increase in static pressure within the ductwork. Static pressure refers to the air pressure that exists within a duct even when there is no airflow. When the duct length exceeds the standard design, the air encounters greater resistance, leading to a rise in static pressure. This increase in static pressure has a detrimental impact on airflow. Airflow, which represents the volume of air moving through the ductwork, decreases significantly as static pressure rises. This reduction in airflow directly leads to diminished cooling capacity. The air conditioner struggles to deliver sufficient conditioned air to effectively cool the intended spaces. Moreover, the energy efficiency of the system drops due to the inefficient use of energy.
Conversely, when duct lengths fall short of the standard design, the actual static pressure inside the duct drops below the standard design static pressure. This decrease in static pressure leads to an unintended increase in airflow resulting in increased power consumption and reduced energy efficiency. The air conditioner is forced to work harder to push the excessive airflow through the ductwork, resulting in higher electricity consumption. Additionally, the increased airflow can generate unwanted noise levels, disrupting the occupants' comfort.
Thus, there is a need for a system which can intelligently determine the actual static pressure in the duct and control the motor speed of an indoor unit to deliver consistent airflow against varying internal and/or external static pressure, thereby improving overall performance and resulting in improved occupant’s comfort.
SUMMARY
This summary is provided to introduce concepts of the invention related to a system and method delivering consistent airflow in a ducted Air Conditioning system, as disclosed herein. This summary is neither intended to identify essential features of the invention as per the present invention nor is it intended for use in determining or limiting the scope of the invention as per the present invention.
In accordance with the present invention, a method for delivering consistent airflow in a ducted Air Conditioning system, the method comprising: receiving, by a controller, a DC supply voltage (Vdc) from an outdoor unit (ODU); generating, by the controller, a pulse width modulated voltage signal (Vs) based on the DC supply voltage (Vdc) to drive a fan motor of an indoor unit (IDU) to deliver airflow in a duct coupled to the indoor unit (IDU); receiving, by the controller, feedback from the fan motor, wherein the feedback being a rotation speed (RPM) of the fan motor; estimating, by the controller, an actual static pressure in the duct based on the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs); determine, by the controller, a target fan motor speed to deliver consistent airflow based on the actual static pressure; adjusting, by the controller, the pulse width modulated voltage signal (Vs) to drive the fan motor at the target fan motor speed to deliver consistent airflow.
In an embodiment, the controller further configured to generate a filter blockage alarm, if the actual static pressure in the duct is more than 20% of a predefined statice pressure for the indoor unit (IDU).
In an embodiment, the pulse width modulated voltage signal (Vs) is generated based on linear correlation with the DC supply voltage (Vdc).
In an embodiment, the actual static pressure is estimated based on liner correlation with the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs).
In an embodiment, the target fan motor speed is determined based on liner correlation with the actual static pressure in the duct at constant airflow.
In an embodiment, the DC supply voltage (Vdc) is feedback from the outdoor unit (ODU) to the controller of the indoor unit (IDU).
In another aspect of the present invention, an Air Conditioning system for delivering consistent airflow, the air conditioning system comprising: an outdoor unit (ODU) communicably coupled with an indoor unit (IDU); the indoor unit (IDU) comprises: an air inlet opening and an air outlet opening for air flow; a filter attached at the air inlet opening for air filtration; and a controller operatively coupled with a fan motor and the outdoor unit (ODU); wherein the controller is configured to receive a DC supply voltage (Vdc) from the outdoor unit (ODU); the controller is configured to generate a pulse width modulated voltage signal (Vs) based on the DC supply voltage (Vdc), and drives the fan motor of the indoor unit (IDU) to deliver airflow in a duct coupled to the indoor unit (IDU); the fan motor is configured to generate feedback for the controller, wherein the feedback is a rotation speed (RPM) of the fan motor; the controller is configured to estimate an actual static pressure in the duct based on the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs); determine a target fan motor speed, by the controller, to deliver consistent airflow based on the actual static pressure at constant airflow; adjusting the pulse width modulated voltage signal (Vs), by the controller, to drive the fan motor at the target fan motor speed to deliver consistent airflow.
In an embodiment the controller further configured to generate a filter blockage alarm if the actual static pressure in the duct is more than 20% of a predefined statice pressure for the indoor unit (IDU).
In an embodiment, the pulse width modulated voltage signal (Vs) is generated based on liner correlation with the DC supply voltage (Vdc).
In an embodiment, the actual static pressure is estimated based on liner correlation with the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs).
In an embodiment, the target fan motor speed is determined based on liner correlation with the actual static pressure in the duct at constant airflow.
In an embodiment, the DC supply voltage (Vdc) is feedback from the outdoor unit (ODU) to the controller of the indoor unit (IDU).
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The detailed description is described with reference to the accompanying figures.
Figure 1 illustrates a typical ducted air conditioning system including an indoor unit coupled with a duct and an outdoor unit, according to an exemplary implementation of the present disclosure.
Figure 2 illustrates an indoor ducted room air conditioning.
Figure 3 illustrates a filter coupled to the indoor unit, according to an exemplary implementation of the present disclosure.
Figure 4 illustrates a block diagram, according to an exemplary implementation of the present disclosure.
Figure 5 illustrates a flow diagram for delivering consistent airflow against variable internal and external static pressure, according to an exemplary implementation of the present disclosure.
Figure 6 illustrates a co-relation graph between initial PWM voltage signal (Vs) verses DC supply voltage (Vdc), according to an exemplary implementation of the present disclosure.
Figure 7 illustrates a co-relation graph between statice pressure (pa) verses fan motor speed (RPM) at the constant PWM Voltage signal, according to an exemplary implementation of the present disclosure.
Figure 8 illustrates a co-relation graph between the fan motor speed (RPM), verses actual statice pressure (pa) at constant airflow, according to an exemplary implementation of the present disclosure.
It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.
DETAILED DESCRIPTION
The present disclosure describes a method and system for delivering consistent airflow against variable internal and external static pressure.
In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure may be practiced without these details. One skilled in the art will recognize that embodiments of the present disclosure, some of which are described below, may be incorporated into a number of systems.
However, the systems and methods are not limited to the specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the presently disclosure and are meant to avoid obscuring of the presently disclosure.
It should be noted that the description merely illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
The conventional ducted air conditioning system consists of an indoor unit and an outdoor unit that is used for comfort cooling in a defined space. In such air conditioning systems, ducts serve as critical components that transport conditioned air from the indoor unit to various areas for a defined space example a building or rooms. In the case of standard ducted split air conditioners, indoor units are typically connected to ducts of varying lengths, as illustrated in figure 1. However, when duct lengths deviate significantly from the standard design, it can lead to performance issues and energy inefficiencies. For example, excessive duct length can result in an increase in static pressure within the ductwork. Static pressure refers to the air pressure that exists within a duct even when there is no airflow. When the duct length exceeds the standard design, the air encounters greater resistance, leading to a rise in static pressure. This increase in static pressure has a detrimental impact on airflow. Airflow, which represents the volume of air moving through the ductwork, decreases significantly as static pressure rises. This reduction in airflow directly leads to diminished cooling capacity. The air conditioner struggles to deliver sufficient conditioned air to effectively cool the intended spaces. Moreover, the energy efficiency of the system drops due to the inefficient use of energy.
Conversely, when duct lengths fall short of the standard design, the actual static pressure inside the duct drops below the standard design static pressure. This decrease in static pressure leads to an unintended increase in airflow resulting in increased power consumption and reduced energy efficiency. The air conditioner is forced to work harder to push the excessive airflow through the ductwork, resulting in higher electricity consumption. Additionally, the increased airflow can generate unwanted noise levels, disrupting the occupants' comfort. Thus, there is a need for a system which can intelligently determine the actual static pressure in the duct and control the motor speed of an indoor unit to deliver consistent airflow against varying internal and/or external static pressure, to improve overall performance the system and resulting in improved occupant’s comfort.
In the ducted air conditioning system, static pressure plays a significant role. Basically, in the ducted air conditioning systems there are two types of static pressure i.e., internal static pressure (ISP) and external static pressure (ESP). The Internal Static Pressure (ISP) refers to the pressure within the air handler and ductwork. It's the resistance the air encounters as it moves through the system, including the air handler fan, filters, coils, and duct turns and fittings. High internal static pressure indicates clogged filters, dirty coils, or inadequate ductwork design, leading to reduced airflow, inefficient cooling/heating, and increased energy consumption and low ISP may occur due to leaks in the ductwork or insufficient blower fan capacity, leading to poor air distribution and inadequate cooling/heating in some areas. The External Static Pressure (ESP) refers to the pressure required to overcome the resistance of the entire duct system outside of the air handler. This includes the friction of air flowing through ducts, grills, and registers. High ESP can result in excessive noise from the system, increased strain on the blower fan, and potential component damage and low ESP can lead to inadequate airflow reaching certain rooms, causing uneven cooling/heating and discomfort. In this disclosure, the internal static pressure and the external static pressure will be referred to as static pressure for better understanding.
The present subject matter describes a method for determining the actual static pressure in the duct and regulate the motor speed of the indoor device of the ducted air conditioning system to deliver consistent airflow against varying internal and/or external static pressure.
Referring to figure 1, Figure 1 illustrates simplified diagram of a ducted air conditioning system, in accordance with an embodiment of the present disclosure. Although the system is depicted to include one or few components, indoor unit, outdoor unit, and duct arranged in a particular arrangement in the present disclosure, it should not be taken to limit the scope of the present disclosure. The ducted air conditioning system includes components such as an indoor unit (IDU) 400, an outdoor unit (ODU), a duct, and a power supply unit, etc. Each of such components is usually installed in plurality. The above-described components of the ducted air-conditioning system are merely illustrative. Thus, the components are not limited particularly to these ones and all the components are not necessarily needed. In addition, another type of device that is not included in the above-described components of the ducted air-conditioning system but controls the state of the air in a room/or a defined space may be a component.
Various components of the indoor unit (IDU) and the outdoor unit (ODU) of the ducted air conditioning system are communicably coupled to each other via a network. The network may include wired or wireless communication protocols. In an embodiment, the network may include, but not limited to a local area network LAN, a wide area network WAN (e.g., the Internet), a mobile network (for e.g., GSM (Global System for Mobile Communication), GPRS (General Packet Radio Service), EDGE (Enhanced Data for Global Evolution), etc.).
In an embodiment, the number of the indoor unit (IDU) and the outdoor unit (ODU) of the ducted air-conditioning system is not limited to this example. For example, two or more indoor units (IDU) and the outdoor units (ODU) may be provided in the ducted air conditioning system.
Referring to figures 2 and 3, figures 2 and 3 illustrate an indoor unit (IDU) (400) of the ducted air conditioning system. The IDU (400) at least include one or more controllers (401), a fan blower connected to a motor (hereafter referred as fan motor) (402), a memory, a filter, etc. The motor is either an AC induction motor or brushless DC motor. Various components of the indoor unit (400) are communicably coupled to each other via a network and may communicate with each other via a bus or a centralized circuitry (not shown in figures). In some embodiments, the network may include wired or wireless communication protocols. It is noted that although the indoor unit (400) is depicted to include only one controller (401), the motor (402) may include a number of controllers or motors.
In an embodiment, the memory is capable of storing machine-executable instructions. The memory may include volatile or non-volatile memories, or a combination thereof. For example, the memory may be a random-access memory (RAM), a read only memory (ROM), flash memory, a hard disk, or any other storage medium.
Further, the controller (401) of the IDU is capable of executing the machine executable instructions to perform the functions described herein. In an embodiment, the controller (401) may be implemented as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core processors. For example, the controller (401) may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), or the like.
In an embodiment, the indoor unit (IDU) (400) has an air outlet opening on the first side to throw air in the duct, when the fan motor (402) is operated, and an air inlet opening on the second side of the indoor unit (400) to receive air. The opening can be of any size or shape but not limited to square, oval, round, rectangular, etc. Further, a filter is attached to the air inlet opening of the IDU (400), wherein the filter being an air filter and used to filter the air.
Referring to figure 4, the controller (401) and the fan motor (402) of the indoor unit (IDU) (400) are communicably coupled to one another. The controller (401) is configured to drive the fan motor (402). The fan motor can be either an AC induction motor or brushless DC motor. During an operation of the air conditioning system, the controller (401) is configured to generate a Pulse Width Modulation (PWM) signal to operate the fan motor (402) to blow air in the duct. The generation of PWM signal is based on the static pressure in the duct, which is determined by the controller (401) of the indoor unit (IDU) (400). The fan motor (402) and the controller (401) of the indoor unit (IDU) (400) are operatively coupled to perform the operation described in figure 5.
Figure 5 is a flowchart depicting a method for delivering consistent airflow in the ducted air conditioning system, in accordance with an embodiment of the present disclosure. The method/steps depicted in the flowchart may be executed by the controller (401) of the indoor unit (400). As shown in figure 5, the method includes the following steps: At step 1001, the ducted air conditioning system is turned ON. In this step, power is supplied to the system.
At step 1002, the controller (401) of the indoor unit (IDU) (400) receives feedback of DC supply voltage (Vdc) value from the outdoor unit (ODU). In this step, the controller receives a DC supply voltage (Vdc) value which is at the outdoor unit (ODU).
At step 1003, after receiving the DC supply voltage (Vdc) value, the controller (401) is configured to generate the initial voltage signal (Vs) based on linear correlation with the DC supply voltage value, wherein the initial Vs is a generated PWM voltage signal.
In an example, the linear correlation between the initial Vs and the DC supply voltage value is expressed by a liner equation:
Vs=a ×Vdc+b
where ‘Vs’ is the pulse width modulated voltage signal, ‘Vdc’ is the DC supply voltage, ‘a’ is constant value of -0.0049, and ‘b’ is constant value of 5.3809.
With the above liner correlation formula, the linear relationship between the initial Vs and the DC supply voltage (Vdc) value is determined. It understood that as the DC supply voltage increases, the pulse width modulated voltage also increases. This linear relationship between the initial Vs and the DC supply voltage (Vdc) value is represented in a graph of figure 6. As it can be seen from the graph of figure 6, the initial Vs and the DC supply voltage value are linearly correlated with one another i.e., as the DC supply voltage increases, the pulse width modulated voltage also increases proportionally. The term initial voltage signal (Vs) is pulse width modulated (PWM) voltage signal (Vs). thus, these terms are used interchangeably.
Optionally, it is understood to the person skilled in the art that, as input voltage increases to the system, the voltage signal provided to drive the motor also increases.
At step 1004, the generated initial voltage signal (Vs) is supplied to the fan motor (402) by the controller (401) of the IDU (400). Based on the initial voltage signal Vs received at the fan motor (402), the fan motor (402) is driven at a certain constant speed (RPM).
At step 1005, the fan motor (402) reads the actual rotation speed at the provided initial Vs, and sends the feedback to the controller (401), where the feedback being an actual rotation speed of the fan motor (402) at the provided initial Vs. In this step, the fan motor 402 may include one or more sensor to determine the speed of the motor. In an example, the fan motor 402 has an inbuilt hall sensor which provides pulses which have a correlation with the speed of the motor. In respect of the present subject matter, the motor gives 12 pulses for each rotation of the motor shaft. The Controller (401) counts the number of pulses received at a fixed interval of time and thus calculates the speed of the motor. The speed of the motor can be calculated with any similar type of sensor which is not limited to hall sensor.
At step 1006, after receiving the feedback from the fan motor (402) by the controller (401) of the IDU (400), the controller (401) estimates an actual static pressure in the duct. In this step, the actual static pressure in the duct is determined based on linear correlation between the current speed of the fan motor (402) and the static pressure in the duct at the provided voltage signal (Vs). It is commonly known that all the systems are designed for a standard static pressure, however the real-life scenarios are different. Thus, there can be a change into the static where the system is being installed. It is also understood that due to the rise in the static pressure in the duct, the fan motor (402) speed also increases.
In an example, upon receiving the initial Vs, such as 3.80 at the fan motor (402), the fan motor (402) operates at a consistent speed, such as 1103 RPM. As the system's static pressure rises, the fan motor (402) speed dynamically increases while maintaining the initial Vs, this is clearly illustrated in the below table 1.

As illustrated in the above table 1, it is note here that although the initial Vs is same, the speed of the fan motor (402) is increased due to rise in the static pressure, but the airflow has significantly reduced. Therefore, it can be said that the static pressure in the system and the rotation speed of the fan motor (402) are correlated at the constant Vs i.e., provided initial voltage signal Vs. This is clearly illustrated with the help of a graph of figure 7, which represents static pressure (pa) vs. fan motor speed (RPM) at the constant Vs.
Therefore, to estimate the actual static pressure in the system, the controller (401) after receiving the feedback of actual rotating speed of the fan motor (402), determines the actual static pressures (pa) by linearly correlating with the actual rotating speed of the fan motor (402) at the generated PWM voltage signal (Vs). In an example according to the present subject matter, the linear correlation between the static pressure and the actual rotating speed of the fan motor (402) may be expressed by a liner equation:
y=p ×x+q
where ‘y’ is the actual static pressure, ‘x’ is the actual running speed (RPM) feedback from the fan motor (402), ‘p’ is constant value of 0.4218 and ‘q’ is constant value of -460.92.
The liner correlation between the static pressure vs. the fan motor speed (RPM) at constant Vs is represented in a graph of figure 7. As it can be seen from the graph of figure 7, the static pressure and the actual rotating speed of the fan motor at a constant Vs are linearly correlated with one another i.e., as the static pressure rises, the actual running speed also increases proportionally, while maintaining constant Vs by the controller (401).
At step 1007, following the estimating of the actual static pressure in the system, the controller (402) compares the estimated actual static pressure with a predetermined threshold. This threshold is set at 20% of the maximum allowable static pressure within the standard range for the specific Indoor Unit (IDU) (400). If the estimated actual static pressure exceeds 20% of the designated standard static pressure range for the IDU, the controller (402) will jump at step 1008 and trigger a filter blockage alarm. If the estimated actual static pressure is within 20% of the designated standard static pressure range for the IDU, the controller (402) will jump at step 1009.
At step 1009, the controller (401) determines a target fan motor speed to deliver a consistent airflow. It is important to note here that due to the increase in the static pressure, the airflow (CFM) delivered by the Indoor unit reduces, and this phenomenon is clearly understood from table 1 provided above. Further, to ensure the steady and consistent airflow at the estimated static pressure (pa), the controller (401) determines the target speed for the fan motor (402) i.e., at what optimal speed the fan motor (402) should be operated to deliver the consistent airflow while mitigating the static pressure. To determine the target fan motor (402) speed, the controller (401) correlates the estimated actual static pressure with the rotation speed of the fan motor (402) at the constant airflow.
Within the context of the present subject matter, constant airflow can be defined as, each ducted air conditioner indoor unit comes with declared airflow from manufacturer which can be considered as "Standard Airflow". To maintain this "standard airflow" irrespective of Static pressure (Internal or External static pressure) can be considered as Constant airflow. In an exemplary embodiment, the manufacturer "standard air flow" declared is 550 CFM. Hence to maintaining 550 CFM (within tolerance of +/-25 CFM) even at different static (Internal or External static pressure) can be termed as constant airflow.
In an exemplary embodiment of the present disclosure, the below table 2 illustrates that at the constant airflow, as the static pressure rises the fan motor (402) speed needs to be increased. In other words, the data in table 2 suggest that there is linear correlation between fan motor speed (RPM) and static pressure (pa) at constant airflow (CFM) such as 550 CFM, as represented in graph of figure 8.

In an example according to the present subject matter, the linear correlation between the static pressure and the target rotating speed of the fan motor (402) at constant airflow may be expressed by a liner equation:
y=r ×x+s
where ‘y’ is the target fan motor speed, ‘x’ is the actual static pressure, ‘r’ is constant value of -6.5636 and ‘s’ is constant value of 1054.9.
In another example according to the present subject matter, considering data of table 2, when the controller determines that the actual static pressure in the system is 30 (pa) and in order to deliver consistent airflow of 550 CFM, the fan motor shall be operated at 1247 RPM. Thus, the Controller determines the target fan motor speed. Furthermore, in order to increase the rotation speed of the fan motor (402), the voltage signal provided by the controller (401) to drive the fan motor (402) has to be increased i.e., the PWM voltage signal (Vs) provided to the fan motor needs to be increased.
At step 1010, after determining the target rotation speed of the fan motor (402), the controller (401) adjusts the PWM voltage signal (Vs) for the fan motor (402) to operate the fan motor (402) at the determined target speed. Once the fan motor (402) is operated at the target speed, the IDU (400) delivers the consistent airflow, the controller (401) exits the loop at step 1012.
In an embodiment of the present subject matter, the process or method defined in figure 5 is performed by the controller (401) of the IDU (400) at every start of the ducted air conditioning system.
It can be understood that the above-mentioned method of delivering consistent airflow can be implemented by the indoor unit of the air conditioning system or a like. The method for determining the actual static pressure and method of delivering consistent airflow against varying internal or external static pressure, as mentioned above are all examples and do not constitute any limitation to the present disclosure. In fact, method for determining the actual static pressure and method of delivering consistent airflow against varying internal or external static pressure can be applied to the technical solution of the present disclosure.
In yet another embodiment, the process defined above in accordance with figure 5, the ducted split air conditioning system with DC motor in the indoor unit provided at least following advantages: total static pressure prediction without any current or static pressure sensing circuit in the controller or usage of any hardware. Delivery of consistent air flow irrespective to the actual static proposed to the system. Actual filter blockage alarm declaration with more accuracy compared to existing solutions available for this alarm declaration. Improved energy efficiency through more cooling capacity and less power consumption. Improved human comfort through optimum cooling capacity, reduced noise level and consistent airflow delivery. No cost addition in the controller or installed system for total static pressure prediction and filter blockage alarm declaration.
In an embodiment, it should be noted that the figures and correlation mentioned are for delivering consistent airflow value i.e., 550, disclosed herein should not limit the scope of the present disclosure. The person skilled in the art would by plotting the same correlation between the target fan motor speed and actual static pressure for different value of consistent airflow value, the fan motor target speed for delivering different consistent airflow has also been derived.
In a first aspect, according to the one or more embodiments of the present disclosure, a method for delivering consistent airflow in a ducted Air Conditioning system is provided. The method comprising: receiving, by a controller, a DC supply voltage (Vdc) from an outdoor unit (ODU); generating, by the controller, a pulse width modulated voltage signal (Vs) based on the DC supply voltage (Vdc) to drive a fan motor of an indoor unit (IDU) to deliver airflow in a duct coupled to the indoor unit (IDU); receiving, by the controller, feedback from the fan motor, wherein the feedback being a rotation speed (RPM) of the fan motor; estimating, by the controller, an actual static pressure in the duct based on the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs); determining, by the controller, a target fan motor speed to deliver consistent airflow based on the actual static pressure at constant airflow; and adjusting, by the controller, the pulse width modulated voltage signal (Vs) to drive the fan motor at the target fan motor speed to deliver consistent airflow.
According to one or more embodiments of the present disclosure, the controller is further configured to generate a filter blockage alarm, if the actual static pressure in the duct is more than 20% of a predefined statice pressure for the indoor unit (IDU).
According to one or more embodiments of the present disclosure, the pulse width modulated voltage signal (Vs) is generated based on linear correlation with the DC supply voltage (Vdc). The linear correlation can be expressed as Vs=a ×Vdc+b , where ‘Vs’ is the pulse width modulated voltage signal, ‘Vdc’ is the DC supply voltage, ‘a’ is -0.0049, and ‘b’ is 5.3809.
According to one or more embodiments of the present disclosure, the actual static pressure is estimated based on linear correlation with the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs). The linear correlation can be expressed as y=p ×x+q , where ‘y’ is the actual static pressure, ‘x’ is the actual running speed (RPM) feedback from the fan motor, ‘p’ is 0.4218 and ‘q’ is -460.92.
According to one or more embodiments of the present disclosure, the target fan motor speed is determined based on linear correlation with the actual static pressure in the duct at constant airflow. The linear correlation can be expressed as y=r ×x+s , where ‘y’ is the target fan motor speed, ‘x’ is the actual static pressure, ‘r’ is -6.5636 and ‘s’ is 1054.9.
According to one or more embodiments of the present disclosure, the DC supply voltage (Vdc) is feedback from the outdoor unit (ODU) to the controller (401) of the indoor unit (IDU).
In a second aspect, according to one or more embodiments of the present disclosure provides an Air Conditioning system for delivering consistent airflow. The air conditioning system comprising: an outdoor unit (ODU) communicably coupled with an indoor unit (IDU); the indoor unit (IDU) comprises: an air inlet opening and an air outlet opening for air flow; a filter attached at the air inlet opening for air filtration; and a controller operatively coupled with a fan motor and the outdoor unit (ODU); wherein the controller is configured to receive a DC supply voltage (Vdc) from the outdoor unit (ODU); the controller (401) is configured to generate a pulse width modulated voltage signal (Vs) based on the DC supply voltage (Vdc), and drives the fan motor of the indoor unit (IDU) to deliver airflow in a duct coupled to the indoor unit (IDU); the fan motor is configured to generate feedback for the controller, wherein the feedback is a rotation speed (RPM) of the fan motor; the controller is configured to estimate an actual static pressure in the duct based on the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs); determine a target fan motor speed, by the controller, to deliver consistent airflow based on the actual static pressure at constant airflow; adjust the pulse width modulated voltage signal (Vs), by the controller, to drive the fan motor at the target fan motor speed to deliver consistent airflow.
According to one or more embodiments of the present disclosure, the controller further configured to generate a filter blockage alarm, if the actual static pressure in the duct is more than 20% of a predefined statice pressure for the indoor unit (IDU).
According to one or more embodiments of the present disclosure, the pulse width modulated voltage signal (Vs) is generated based on linear correlation with the DC supply voltage (Vdc). The linear correlation can be expressed as Vs=a ×Vdc+b , where ‘Vs’ is the pulse width modulated voltage signal, ‘Vdc’ is the DC supply voltage, ‘a’ is -0.0049, and ‘b’ is 5.38099.
According to one or more embodiments of the present disclosure, the actual static pressure is estimated based on linear correlation with the feedback from the fan motor at the generated pulse width modulated voltage signal (Vs). The linear correlation can be expressed as y=p ×x+q , where ‘y’ is the actual static pressure, ‘x’ is the actual running speed (RPM) feedback from the fan motor, ‘p’ is 0.4218 and ‘q’ is -460.92.
According to one or more embodiments of the present disclosure, the target fan motor speed is determined based on linear correlation with the actual static pressure in the duct at constant airflow. The linear correlation can be expressed as y=r ×x+s , where ‘y’ is the target fan motor speed, ‘x’ is the actual static pressure, ‘r’ is -6.5636 and ‘s’ is 1054.9.
According to one or more embodiments of the present disclosure, wherein the DC supply voltage (Vdc) is feedback from the outdoor unit (ODU) to the controller of the indoor unit (IDU).
The above description is merely preferred embodiments of the present disclosure and an illustration of applied technical principles. Those skilled in the art should understand that the disclosed scope involved in the present disclosure is not limited to technical solutions formed by a specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or equivalent features thereof without departing from the above disclosed concept, for example, a technical solution formed by replacing the above features with technical features having similar functions as the above features and being disclosed in the present disclosure (without limitation).
In addition, although operations are depicted in a specific order, this should not be understood as requiring these operations to be performed in the specific order as shown or in a sequential order. Under certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the present disclosure. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the [context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.
The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.
, C , Claims:
1. A method for delivering consistent airflow in a ducted Air Conditioning system, the method comprising:
receiving, by a controller (401), a DC supply voltage (Vdc) from an outdoor unit (ODU);
generating, by the controller (401), a pulse width modulated voltage signal (Vs) based on the DC supply voltage (Vdc) to drive a fan motor (402) of an indoor unit (IDU) to deliver airflow in a duct coupled to the indoor unit (IDU);
receiving, by the controller (401), feedback from the fan motor (402), wherein the feedback being a rotation speed (RPM) of the fan motor (402);
estimating, by the controller (401), an actual static pressure in the duct based on the feedback from the fan motor (402) at the generated pulse width modulated voltage signal (Vs);
determining, by the controller (401), a target fan motor speed to deliver consistent airflow based on the actual static pressure at constant airflow; and
adjusting, by the controller (401), the pulse width modulated voltage signal (Vs) to drive the fan motor (402) at the target fan motor speed to deliver consistent airflow.
2. The method as claimed in claim 1, wherein the controller (401) is further configured to generate a filter blockage alarm, if the actual static pressure in the duct is more than 20% of a predefined statice pressure for the indoor unit (IDU).
3. The method as claimed in claims 1 or 2, wherein the pulse width modulated voltage signal (Vs) is generated based on linear correlation with the DC supply voltage (Vdc).
4. The method as claimed in claims 1 or 2, wherein the actual static pressure is estimated based on linear correlation with the feedback from the fan motor (402) at the generated pulse width modulated voltage signal (Vs).
5. The method as claimed in claims 1 or 2, wherein the target fan motor speed is determined based on linear correlation with the actual static pressure in the duct at constant airflow.
6. The method as claimed in claims 1 to 5, wherein the DC supply voltage (Vdc) is feedback from the outdoor unit (ODU) to the controller (401) of the indoor unit (IDU).
7. An Air Conditioning system for delivering consistent airflow, the air conditioning system comprising:
an outdoor unit (ODU) communicably coupled with an indoor unit (IDU) (400);
the indoor unit (IDU) (400) comprises:
an air inlet opening and an air outlet opening for air flow;
a filter attached at the air inlet opening for air filtration; and
a controller (401) operatively coupled with a fan motor (402) and the outdoor unit (ODU);
wherein the controller (401) is configured to receive a DC supply voltage (Vdc) from the outdoor unit (ODU);
the controller (401) is configured to generate a pulse width modulated voltage signal (Vs) based on the DC supply voltage (Vdc), and drives the fan motor (402) of the indoor unit (IDU) to deliver airflow in a duct coupled to the indoor unit (IDU);
the fan motor (402) is configured to generate feedback for the controller (401), wherein the feedback is a rotation speed (RPM) of the fan motor (402);
the controller (401) is configured to estimate an actual static pressure in the duct based on the feedback from the fan motor (402) at the generated pulse width modulated voltage signal (Vs);
determine a target fan motor speed, by the controller (401), to deliver consistent airflow based on the actual static pressure at constant airflow;
adjusting the pulse width modulated voltage signal (Vs), by the controller (401), to drive the fan motor (402) at the target fan motor speed to deliver consistent airflow.
8. The system as claimed in claim 7, wherein the controller (401) further configured to generate a filter blockage alarm, if the actual static pressure in the duct is more than 20% of a predefined statice pressure for the indoor unit (IDU).
9. The system as claimed in claims 7 or 8, wherein the pulse width modulated voltage signal (Vs) is generated based on linear correlation with the DC supply voltage (Vdc).
10. The system as claimed in claims 7 or 8, wherein the actual static pressure is estimated based on linear correlation with the feedback from the fan motor (402) at the generated pulse width modulated voltage signal (Vs).
11. The system as claimed in claims 7 or 8, wherein the target fan motor speed is determined based on linear correlation with the actual static pressure in the duct at constant airflow.
12. The system as claimed in claims 7 to 12, wherein the DC supply voltage (Vdc) is feedback from the outdoor unit (ODU) to the controller (401) of the indoor unit (IDU).