Automatic air conditioning control system

Abstract

The present invention discloses a dual closed-loop based automatic air conditioning control system capable of stably maintaining target airflow and target pressure states by using an airflow sensor and a pressure sensor to measure the airflow status of air entering the room and the pressure status of the mixing chamber in real time, and by controlling an outdoor air damper, a return damper, an exhaust damper, a supply fan, and a blower fan in conjunction based on the measured data.

Description

Technology Field

[0001] The present invention relates to an automatic air conditioning control system, and more specifically, to a dual closed-loop based automatic air conditioning control system capable of stably maintaining a target outside air volume and target pressure state by using an air volume sensor and a pressure sensor to measure the air volume of air entering the room and the pressure state of a mixing chamber in real time, and controlling an outside air damper, a return damper, an exhaust damper, a supply fan, and a blower fan in conjunction based on the measured data. Background Technology

[0003] Generally, HVAC (Heating, Ventilation and Air Conditioning) systems are installed and operated in buildings, industrial facilities, hospitals, clean rooms, and multi-use facilities to maintain indoor air quality and ensure ventilation performance.

[0004] This air conditioning system is configured to maintain the temperature, humidity, and air quality of the indoor space at a constant level by supplying outside air into the room and exhausting polluted indoor air.

[0005] Conventional air conditioning systems can be operated by controlling the mixing ratio of the inflow of outside air and the return air inside the room using an outside air damper, a return damper, a supply fan, and an exhaust fan.

[0006] In particular, to ensure indoor ventilation, it can be configured to maintain a target airflow state by controlling the rotational speed of the supply or exhaust fan or adjusting the opening rate of the outside air damper.

[0007] However, conventional HVAC systems often perform airflow and pressure control using a single control loop or a simple PID (Proportional-Integral-Derivative) method without being independent of each other, so there is a problem where airflow and pressure states interfere with each other when changes in the external environment or indoor load occur.

[0008] In addition, conventional air conditioning systems often respond by simply increasing the fan's rotation speed even when airflow is insufficient, which can lead to increased unnecessary power consumption and problems such as control hunting or airflow overshoot caused by excessive pressure changes.

[0009] Therefore, there is a need for an automatic air conditioning control system that can independently control real-time airflow and pressure states while performing interconnected control, actively adjust target airflow and pressure states in response to changes in indoor air quality, and maintain stable control performance even in long-term operating environments. The problem to be solved

[0011] The present invention was created out of the aforementioned necessity, and aims to provide a dual closed-loop based automatic air conditioning control system capable of stably maintaining target outside air volume and target pressure states by using airflow and pressure sensors to measure the airflow status of air entering the room and the pressure status of the mixing chamber in real time, and by controlling the outside air damper, return damper, exhaust damper, supply fan, and blower fan in conjunction based on the measured data. means of solving the problem

[0013] To achieve the above-mentioned purpose, the automatic air conditioning control system comprises an air conditioning unit including an outside air damper for introducing outside air, a return damper for introducing indoor return air, a mixing chamber where the air introduced from the outside air damper and the return damper is mixed, a supply fan for supplying air from the mixing chamber to the room, an exhaust damper for discharging air from the mixing chamber to the outside, and a blower fan for discharging air through the exhaust damper; an airflow sensor installed in a path moving from the mixing chamber to the supply fan to measure the airflow; a pressure sensor installed in the mixing chamber to measure the pressure difference with the outside; and a control unit that controls the outside air damper, the return damper, the supply fan, the exhaust damper, and the blower fan based on data received from the airflow sensor and the pressure sensor. The control unit includes a first closed loop for setting a target pressure difference in the mixing chamber when the measured value of the airflow sensor falls short of a target airflow value, and controls the outside air damper, the return damper, and the above so that the measured value of the pressure sensor reaches the target pressure difference. It is characterized by performing double closed-loop control including a second closed loop that controls the internal pressure of the mixing chamber by controlling the opening rate of the exhaust damper and the rotational speeds of the supply fan and the blower fan.

[0014] The above control unit is characterized by adjusting the target pressure difference between the mixing chamber and the outside as the deviation between the measured value of the airflow sensor and the target airflow value increases, thereby strengthening the force of external air introduction.

[0015] The above control unit is characterized by performing the adjustment of the opening rates of the outside air damper, the return damper, and the exhaust damper, and the control of the rotational speeds of the supply fan and the blower fan in conjunction with each other to maintain the above target pressure difference.

[0016] The above control unit is characterized by performing steady-state control that minimizes airflow fluctuations by controlling the pressure inside the mixing chamber to maintain the target pressure difference at the time of reaching the target airflow value when the measured value of the airflow sensor reaches the target airflow value.

[0017] The above-mentioned outside air damper, the above-mentioned return damper, and the above-mentioned exhaust damper are each characterized by being configured in a modulating driving method that continuously variably adjusts the opening rate in response to the output signal of the control unit.

[0018] The above supply fan and the above blower fan are each characterized by having their rotational speeds continuously variablely controlled in response to a variable frequency applied from an inverter.

[0019] The first closed loop and the second closed loop are characterized by independently performing individual feedback operations according to a set control cycle.

[0020] The above control unit is characterized by optimizing the convergence speed to the target airflow by updating control parameters for calculating the target pressure difference in real time based on the change trend of the airflow sensor measurement value.

[0021] The above control unit is characterized by receiving real-time environmental data from a carbon dioxide sensor or an air quality sensor installed indoors, and variably setting a target airflow volume of outside air in response to the indoor pollution level based on the received data.

[0022] The above control unit is characterized by including a memory that stores operating data including changes in airflow and pressure resulting from the operation of the outside air damper, the return damper, the supply fan, the exhaust damper, and the blower fan, and an algorithm that analyzes the data accumulated in the memory to update the correction coefficient of the target pressure difference calculation logic based on the airflow error. Effects of the invention

[0024] According to the automatic air conditioning control system of the present invention, the airflow status of air entering the room and the pressure status of the mixing chamber are measured in real time using an airflow sensor and a pressure sensor, and by controlling the outside air damper, return damper, exhaust damper, supply fan, and blower fan in conjunction based on the measured data, the system has the effect of stably maintaining the target airflow and target pressure status. Brief explanation of the drawing

[0026] FIG. 1 is a drawing illustrating the overall configuration of an automatic air conditioning control system according to one embodiment of the present invention. FIG. 2 is a block diagram illustrating the control configuration of an automatic air conditioning control system according to one embodiment of the present invention. FIG. 3 is a flowchart illustrating double closed-loop control of an automatic air conditioning control system according to one embodiment of the present invention. Specific details for implementing the invention

[0027] Hereinafter, an automatic air conditioning control system according to an embodiment of the present invention will be described with reference to the attached drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation.

[0028] Furthermore, the terms described below are defined in consideration of their functions in the present invention, and these may vary depending on the intent or practice of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0030] FIG. 1 is a diagram illustrating the overall configuration of an automatic air conditioning control system according to one embodiment of the present invention, FIG. 2 is a block diagram illustrating the control configuration of an automatic air conditioning control system according to one embodiment of the present invention, and FIG. 3 is a flowchart illustrating double closed-loop control of an automatic air conditioning control system according to one embodiment of the present invention.

[0032] As illustrated in FIGS. 1 to 3, an automatic air conditioning unit according to one embodiment of the present invention includes an air conditioning unit (10), an airflow sensor (20), a pressure sensor (30), and a control unit (40).

[0033] The air conditioning unit (10) is configured to automatically adjust the airflow and pressure of the air supplied to the indoor space to maintain target ventilation conditions.

[0034] This air conditioning unit (10) may include an outside air damper (11) for introducing outside air, a return damper (12) for introducing indoor return air, a mixing chamber (13) where the air introduced from the outside air damper (11) and the return damper (12) is mixed, a supply fan (14) for supplying the air from the mixing chamber (13) to the indoor space, an exhaust damper (15) for discharging the air from the mixing chamber (13) to the outside, and a blower fan (16) for discharging air through the exhaust damper (15).

[0035] At this time, the mixing chamber (13) may be connected to a plurality of ducts to form a path for the movement of outside air, return air, supply air, and exhaust air. These plurality of ducts may include a duct through which outside air moves toward the mixing chamber (13), a duct through which return air from the room moves toward the mixing chamber (13), a duct through which air from the mixing chamber (13) is supplied to the room, and a duct through which air from the mixing chamber (13) is discharged to the outside.

[0036] That is, the outside air introduced through the outside air damper (11) and the indoor return air introduced through the return damper (12) can be mixed with each other inside the mixing chamber (13), and the mixed air can be supplied to the indoor space by the supply fan (14). In addition, some of the air inside the mixing chamber (13) can be discharged to the outside through the exhaust damper (15) and the blower fan (16).

[0037] Here, the outside air damper (11), the return damper (12), and the exhaust damper (15) can each be configured in a modulating driving manner that continuously variably adjusts the opening rate in response to an output signal from the control unit (40). As a result, the amount of outside air entering, the mixing ratio of return air, and the amount of exhaust can be adjusted in real time, and the internal pressure state of the mixing chamber (13) can be controlled more precisely.

[0038] In addition, the rotational speed of the supply fan (14) and the blower fan (16) can be continuously variablely controlled in response to a variable frequency applied from an inverter. That is, the supply volume of the supply fan (14) and the exhaust volume of the blower fan (16) can be actively adjusted in response to the pressure state of the mixing chamber (13) and the target air volume condition, so that stable blowing performance can be maintained even if changes in the external environment or indoor load occur.

[0039] The airflow sensor (20) is configured to measure the airflow by being installed in a duct that moves from the mixing chamber (13) to the supply fan (14). This airflow sensor (20) can detect the flow rate or velocity of the air supplied from the mixing chamber (13) to the room in real time and generate corresponding measurement data.

[0040] Of course, the airflow sensor (20) can be made in various ways, such as a heating wire type, differential pressure type, vane type, or ultrasonic type sensor, and can transmit the measured airflow data to the control unit (40) in the form of an electrical signal.

[0041] The pressure sensor (30) is installed in the mixing chamber (13) and is configured to measure the pressure difference with the outside. This pressure sensor (30) can detect the pressure difference between the internal pressure of the mixing chamber (13) and the external atmospheric pressure in real time and generate corresponding pressure data.

[0042] Specifically, the pressure sensor (30) may be configured to detect differential pressure by including a measuring part that communicates with the internal space and the external space of the mixing chamber (13), respectively, and may transmit the measured data to the control unit (40).

[0043] Of course, the pressure sensor (30) can be configured as a differential pressure sensor, a semiconductor pressure sensor, or a capacitive pressure sensor so as to detect even minute pressure changes.

[0044] Meanwhile, the control unit (40) is configured to control the outside air damper (11), return damper (12), supply air fan (14), exhaust damper (15), and blower fan (16) based on data received from the airflow sensor (20) and pressure sensor (30).

[0045] This control unit (40) may be configured in the form of an electronic control device including a processor, memory, and an input / output control module, and can process measurement data received from the airflow sensor (20) and pressure sensor (30) in real time according to a preset control algorithm. Of course, the control unit (40) can actively control the amount of outside air inflow, the amount of return air inflow, the amount of supply air, and the amount of exhaust air by being electrically connected to the outside air damper (11), the return damper (12), the supply fan (14), the exhaust damper (15), and the blower fan (16) and outputting a control signal.

[0046] At this time, the control unit (40) can perform double closed-loop control including a first closed-loop that sets a target pressure difference of the mixing chamber (13) when the measured value of the airflow sensor (20) falls short of the target airflow value, and a second closed-loop that controls the opening rate of the outside air damper (11), return damper (12), and exhaust damper (15) and the rotation speed of the supply air fan (14) and blower fan (16) so that the measured value of the pressure sensor (30) reaches the target pressure difference.

[0047] Here, it is desirable for the first closed loop and the second closed loop to independently perform individual feedback operations according to the set control period.

[0048] That is, the first closed loop determines whether there is a shortage of airflow by comparing the airflow value measured by the airflow sensor (20) with a preset target airflow value, and if it falls short of the target airflow value, it can set a target pressure difference to induce the inflow of outside air by increasing the pressure difference between the mixing chamber (13) and the outside to satisfy the set minimum outside airflow or standard outside air volume conditions. Accordingly, the inflow force of outside air can be improved, and the supply airflow to the indoor space can be increased.

[0049] At this time, the control unit (40) can continuously correct the target pressure difference so that the actual outside air volume measured through the air volume sensor (20) reaches the target outside air volume.

[0050] In addition, the second closed loop can compare the pressure value measured through the pressure sensor (30) with the target pressure difference value set in the first loop to finely adjust the operating state of the outside air damper (11), return damper (12), exhaust damper (15), supply air fan (14), and blower fan (16) so that the internal pressure of the mixing chamber (13) reaches the target pressure difference.

[0051] Accordingly, the response characteristics to changes in airflow and pressure can be optimized independently, and the mutual interference between the control operations of the first and second closed loops can be minimized, thereby improving control stability and responsiveness.

[0052] Additionally, the control unit (40) can increase the external air introduction force by lowering the set value of the target pressure difference between the mixing chamber (13) and the outside as the deviation between the measured value of the airflow sensor (20) and the target airflow value increases.

[0053] Thus, even when the actual airflow supplied to the indoor space falls significantly short of the target airflow value, the pressure difference in the mixing chamber (13) can be formed more actively, and external air can be flowed in more smoothly through the external air damper (11).

[0054] In particular, the control unit (40) can vary the target pressure difference stepwise or continuously in proportion to the degree of airflow shortage, so that the target airflow state can be reached more quickly and stably.

[0055] In addition, the control unit (40) can gradually reduce the target pressure difference of the mixing chamber (13) as it approaches the target airflow value, thereby suppressing unnecessary energy consumption and air flow fluctuations caused by the formation of an excessive pressure difference, thus ensuring airflow responsiveness and pressure stability simultaneously, and minimizing the control hunting phenomenon caused by rapid pressure changes.

[0056] This control unit (40) can control the opening rate of the outside air damper (11), return damper (12), and exhaust damper (15) and control the rotational speed of the supply air fan (14) and blower fan (16) in conjunction with each other to maintain the target pressure difference.

[0057] That is, when the control unit (40) increases the opening rate of the outside air damper (11) to increase the amount of outside air entering, it controls the opening rate of the return damper (12) to relatively decrease the opening rate of the exhaust damper (15) and the rotation speed of the blower fan (16) to maintain the internal pressure balance of the mixing chamber (13).

[0058] In addition, when the rotational speed of the supply fan (14) increases and the amount of air supplied to the room increases, the control unit (40) can adjust the operating state of the outside air damper (11), return damper (12), exhaust damper (15), and blower fan (16) together in response to the change in internal pressure of the mixing chamber (13).

[0059] At this time, the control unit (40) prioritizes controlling the opening rate of the outside air damper (11), return damper (12), and exhaust damper (15), and if the opening rate of the outside air damper (11), return damper (12), and exhaust damper (15) exceeds a set range or if it is difficult to maintain the target pressure difference, the rotation speed of the supply air fan (14) and blower fan (16) can be additionally corrected and controlled. By doing so, unnecessary power increase of the supply air fan (14) and blower fan (16) can be suppressed, and energy efficiency can be improved and the load of the drive unit reduced.

[0060] The control unit (40) performs steady state control to minimize airflow fluctuations by controlling the pressure inside the mixing chamber (13) to maintain the target pressure difference at the time of reaching the target airflow value when the measured value of the airflow sensor (20) reaches the target airflow value.

[0061] This is because the air volume supplied to the room may fluctuate again if the internal pressure of the mixing chamber (13) changes rapidly even after the target air volume value is reached. Therefore, the control unit (40) can stably control the operating state of the outside air damper (11), return damper (12), exhaust damper (15), supply air fan (14), and blower fan (16) to maintain the target pressure difference formed at the time the target air volume is reached in a reference state.

[0062] Specifically, the control unit (40) can limit or mitigate the target pressure difference change operation of the first closed loop when the measured value of the airflow sensor (20) reaches within the allowable error range of the target airflow value, and can finely adjust the opening rate of the outside air damper (11), return damper (12), and exhaust damper (15) and the rotation speed of the supply air fan (14) and blower fan (16) so that the internal pressure state of the mixing chamber (13) currently formed through the second closed loop is maintained.

[0063] The control unit (40) can optimize the convergence speed to the target airflow by updating the control parameters for calculating the target pressure difference in real time based on the change trend of the airflow sensor (20) measurement value.

[0064] For example, if the rate of increase in airflow is slow or the reduction in deviation from the target airflow value is minimal, the control unit (40) can correct the control parameters to lower the target pressure difference of the mixing chamber (13) more quickly. Conversely, if the airflow approaches the target airflow value quickly or the amount of change in airflow increases rapidly, the control parameters can be adjusted to limit the amount of change in the target pressure difference.

[0065] Thus, the control unit (40) can actively adjust the external air introduction force according to the operating state and converge more quickly and stably to the target airflow value, while effectively suppressing pressure vibrations, airflow overshoot, and control hunting phenomena that may occur due to the formation of an excessive pressure difference or a sudden increase in airflow.

[0066] Furthermore, the control unit (40) receives real-time environmental data from an environmental sensor unit (50) installed indoors and can variably set the target airflow of the outside air in response to the indoor pollution level according to the received data.

[0067] Here, the environmental sensor unit (50) can detect at least one environmental information including indoor carbon dioxide concentration, temperature, humidity, fine dust concentration (PM), and volatile organic compound (VOC) concentration.

[0068] Specifically, the control unit (40) can control the target airflow value of the outside air to increase when the indoor pollution level increases above a preset reference value, so that the opening rate of the outside air damper (11) is increased and the target pressure difference of the mixing chamber (13) can be adjusted, and the amount of outside air introduced is increased, thereby improving the ventilation performance of the indoor space.

[0069] Conversely, if the indoor pollution level remains below the standard value or the indoor air quality is determined to be good, the system can be controlled to reduce the target airflow value of the outside air. Accordingly, the introduction of excessive outside air can be prevented, and unnecessary energy consumption can be reduced.

[0070] At this time, the control unit (40) may include a memory that stores operation data including airflow and pressure changes resulting from the operation of the outside air damper (11), return damper (12), supply air fan (14), exhaust damper (15) and blower fan (16) in a time-series matching manner, and a learning algorithm that analyzes the operation data accumulated in the memory to optimize the calculation logic of the target pressure difference set when there is an airflow error.

[0071] In this case, the algorithm maintains constant control precision regardless of system aging or environmental changes by updating correction coefficients in real-time or periodically based on accumulated data to minimize feedback errors resulting from control results.

[0072] Thus, the automatic air conditioning control system according to the present invention can actively correct control characteristics according to changes in the operating environment, thereby enabling the target airflow and target pressure states to be maintained more stably.

[0073] In addition, since control errors can be continuously corrected even if performance changes in each component or system aging occur due to long-term operation, control precision close to the initial operating state can be maintained for a long period.

[0075] Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0076] Therefore, the true technical scope of protection of the present invention should be determined by the following claims. Explanation of the symbols

[0078] 10: HVAC unit 11: Outside air damper 12: Return damper 13: Mixing chamber 14: Supply fan 15: Exhaust damper 16: Blower fan 20: Airflow sensor 30: Pressure sensor 40: Control unit 50: Environmental sensor unit

Claims

Claim 1 An air conditioning unit comprising an outside air damper for introducing outside air, a return damper for introducing indoor return air, a mixing chamber where air introduced from the outside air damper and the return damper is mixed, a supply fan for supplying air from the mixing chamber to the indoors, an exhaust damper for discharging air from the mixing chamber to the outside, and a blower fan for discharging air through the exhaust damper; an airflow sensor installed in the path moving from the mixing chamber to the supply fan to measure the airflow; and a pressure sensor installed in the mixing chamber to measure the pressure difference with the outside. The automatic air conditioning control system comprises: a control unit that controls the outside air damper, the return damper, the supply air fan, the exhaust damper, and the blower fan based on data received from the airflow sensor and the pressure sensor; wherein the control unit performs double closed-loop control, comprising a first closed-loop that sets a target pressure difference of the mixing chamber when the measured value of the airflow sensor falls short of a target airflow value, and a second closed-loop that controls the opening rate of the outside air damper, the return damper, and the exhaust damper, and the rotational speed of the supply air fan and the blower fan, so that the measured value of the pressure sensor reaches the target pressure difference. Claim 2 An automatic air conditioning control system according to claim 1, wherein the control unit strengthens the introduction force of external air by adjusting the target pressure difference between the mixing chamber and the outside as the deviation between the measured value of the airflow sensor and the target airflow value increases. Claim 3 An automatic air conditioning control system according to claim 1, wherein the control unit performs the control of the opening rate of the outside air damper, the return damper, and the exhaust damper, and the control of the rotational speed of the supply fan and the blower fan in conjunction with each other to maintain the target pressure difference. Claim 4 An automatic air conditioning control system according to claim 1, characterized in that the control unit performs steady-state control to minimize airflow fluctuations by controlling the pressure inside the mixing chamber to maintain the target pressure difference at the time of reaching the target airflow value when the measured value of the airflow sensor reaches the target airflow value. Claim 5 An automatic air conditioning control system according to claim 1, characterized in that the outside air damper, the return damper, and the exhaust damper are each configured in a modulating driving manner that continuously variably adjusts the opening rate in response to the output signal of the control unit. Claim 6 An automatic air conditioning control system according to claim 1, characterized in that the rotational speed of the supply fan and the blower fan is continuously variablely controlled in response to a variable frequency applied from an inverter. Claim 7 An automatic air conditioning control system according to claim 1, wherein the first closed loop and the second closed loop independently perform individual feedback operations according to a set control cycle. Claim 8 An automatic air conditioning control system according to claim 1, wherein the control unit optimizes the convergence speed to the target airflow by updating control parameters for calculating the target pressure difference in real time based on the change trend of the airflow sensor measurement value. Claim 9 An automatic air conditioning control system according to claim 1, wherein the control unit receives real-time environmental data from an environmental sensor unit installed indoors and variably sets a target airflow volume of outside air in response to the indoor pollution level according to the received data. Claim 10 An automatic air conditioning control system according to claim 1, wherein the control unit comprises a memory for storing operating data including airflow and pressure changes resulting from the operation of the outside air damper, the return damper, the supply fan, the exhaust damper, and the blower fan, and an algorithm for analyzing data accumulated in the memory to update a correction coefficient for a target pressure difference calculation logic based on airflow error.

Images