Patent Description:
As global warming continues to intensify, causing the outdoor ambient temperature to rise day by day, the use of air-conditioning systems is becoming more and more common, and has become an indispensable part of daily life. In particular, outdoor electrical equipment, such as communication power supply systems, needs to rely on air-conditioning systems to maintain the temperature of the electrical equipment during operation and avoid damage to the electrical equipment. These air-conditioning systems maintain the temperature of the electrical equipment within a suitable temperature range by the phase change of the refrigerant. Therefore, when the refrigerant is leaking, the air-conditioning system will not be able to maintain its original performance.

<CIT> discloses an integrated HVACR control and protection system which includes a modular and reprogrammable design providing a plurality of possible combinations of power detection, voltage detection, run current detection, transient current detection, temperature detection, universal thermostat interface, peripheral or remote control, and local display and control. The control and protection system is capable of evaluating the relationship between real power used by an HVACR system compressor and other system operating parameters to detect problems early in the failure cycle, i.e., before a failure has progressed to requiring a system shutdown or causing damage to other components. Additionally, a control system and method provide sensorless detection of various HVACR system faults, such as, for example, loss of refrigerant or a refrigerant flow restriction, that impact the relationship between real power and current, voltage, temperature, or other operating parameters. Peripheral or remote control includes wired or wireless system monitoring and parameter programming using a personal digital assistant (PDA), for example utilizing IR communication between the PDA and the control and protection system.

Traditional air-conditioning systems need a pressure sensor to detect whether the gaseous refrigerant in the air-conditioning system is leaking. However, as the outdoor electrical equipment is designed to be modularized, the volume of the air-conditioning systems is also reduced, so that it is difficult to install a pressure sensor in these air-conditioning systems. In addition, installing a pressure sensor will significantly increase the production cost of the air-conditioning system.

Therefore, many air-conditioning systems used in outdoor electrical equipment cannot actively detect a refrigerant leak, and may not reserve space to install other pressure-sensing devices for detection, so users often fail to immediately realize that the refrigerant is leaking, and this can affect the quality of the air-conditioning system. Therefore, how to effectively detect refrigerant leakage in air-conditioning systems in real time and reduce detection costs will become an urgent issue.

The abovementioned problem is inventively solved by a detection method for an air-conditioning system according to appended claim <NUM>. Advantageous embodiments are the subject of the dependent claims.

The air-conditioning system not according to the invention and the detection method according to the invention are described in the following description.

In addition, spatially relative terms, such as "lower," or "bottom," and "upper," or "top," may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It should be understood that if the figures are turned upside-down, the element located on the "lower" side may become the element located on the "upper" side.

It should be appreciated that although the terms "first" and "second" may be used herein to describe various elements, materials and/or portions, these elements, materials and/or portions should not be limited by these terms. These terms are merely intended to distinguish different elements, materials and/or portions. Accordingly, a first element, material and/or portion discussed as follows may be referred to as a second element, material and/or portion without departing from the teaching of some embodiments in the present disclosure.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It should be appreciated that, in each case, the term, which is defined in a commonly used dictionary, should be interpreted as having a meaning that conforms to the relative skills of the present disclosure and the background or the context of the present disclosure, and should not be interpreted in an idealized or overly formal manner unless so defined in the present disclosure. In addition, the terms "substantially," "about" or "approximately" may be recited herein, and are intended to encompass the circumstances or ranges that are substantially the same and exactly the same. It should be noted that unless specially defined, even if the above terms are not recited in the description, it should be interpreted as the same meaning as the above approximate terms that are recited.

Please referring to <FIG> illustrates a schematic diagram of an air-conditioning system <NUM>. As shown in <FIG>, the air-conditioning system <NUM> includes a compressor <NUM>, an evaporator <NUM>, an expansion valve <NUM> and a condenser <NUM>. In some embodiments, the condenser <NUM> is connected to the output end 110B of the compressor <NUM>, and the evaporator <NUM> is connected to the input end 110A of the compressor <NUM>. In this way, the compressor <NUM> may be configured to receive the refrigerant (not shown) from the evaporator <NUM> and exert pressure on the received refrigerant to deliver the refrigerant to the condenser <NUM> in the form of hot gas. In this embodiment, the detector <NUM> may be connected to the compressor <NUM> and is configured to detect the electrical power of the compressor <NUM> during operation. In addition, the expansion valve <NUM> is connected to the condenser <NUM> and the evaporator <NUM> so that the refrigerant may circulate among the compressor <NUM>, the evaporator <NUM>, the expansion valve <NUM> and the condenser <NUM>.

In some embodiments, when the refrigerant is in the evaporator <NUM>, the refrigerant may absorb heat energy and evaporate. When the refrigerant is in the condenser <NUM>, the refrigerant may release heat energy and condense. In some embodiments, the evaporator <NUM> has an evaporation temperature sensor <NUM> to detect the evaporation saturation temperature of the refrigerant, and the condenser <NUM> has a condensation temperature sensor <NUM> to detect the condensation saturation temperature of the refrigerant. In addition, the expansion valve <NUM> can control the amount of refrigerant flowing into the evaporator <NUM> to allow a small amount of refrigerant to pass through. As a result, the refrigerant expands and the pressure and temperature of the refrigerant are decreased, thereby effectively controlling the performance of the air-conditioning system <NUM>.

For example, in the case of cooling down a space (i.e., indoor), the evaporator <NUM> and the expansion valve <NUM> may be installed in the above space (i.e. installed in an indoor unit), and the compressor <NUM> and the condenser <NUM> are installed outside the above-mentioned space (that is, installed in an outdoor unit). In this way, the refrigerant can exchange heat with the indoor air in the evaporator <NUM>, and the refrigerant will evaporate into a gaseous state to cool down the indoor air. The refrigerant evaporated into the gaseous state will be sent to the compressor <NUM> and the condenser <NUM> which are located outside. The refrigerant may exchange heat with the outdoor air in the condenser <NUM>, and the refrigerant will condense into a liquid state and discharge heat energy to the outside. The condensed refrigerant will return to the indoor evaporator <NUM> through the expansion valve <NUM> to realize the refrigerant circulation and cooling effect of the air-conditioning system <NUM>.

In addition, the air-conditioning system <NUM> includes a controller <NUM>, which is electrically connected to the detector <NUM> so as to detect the electrical power of the compressor <NUM> by the detector <NUM>. In some embodiments, the controller <NUM> is electrically connected to the evaporation temperature sensor <NUM> and the condensation temperature sensor <NUM> to detect the evaporation saturation temperature and the condensation saturation temperature of the refrigerant. When the controller <NUM> detects that the electrical power of the compressor <NUM> in operation is less than the power threshold, and the evaporation saturation temperature is higher than the condensation saturation temperature, the controller <NUM> will drive the compressor <NUM> to operate in the full-speed mode so as to detect refrigerant leakage. The method for detecting whether the refrigerant leakage occurs in the air-conditioning system <NUM> will be further described below with reference to <FIG> and <FIG>.

It should be understood that although the various components of the air-conditioning system <NUM> are merely schematically illustrated in <FIG>, the present disclosure is intended to cover various possible actual configurations of components of the air-conditioning system <NUM>. Any configuration that is capable of circulating the refrigerant in the compressor <NUM>, the evaporator <NUM>, the expansion valve <NUM> and the condenser <NUM> is included within the scope of the present disclosure.

<FIG> illustrates a pressure-enthalpy diagram of the refrigerant that is used in the air-conditioning system <NUM>. For example, the refrigerant used in the air-conditioning system <NUM> is, for example, <NUM>,<NUM>,<NUM>,<NUM>-tetrafluoroethane (also known as R134a refrigerant). However, this embodiment merely serves as an illustrative example, not intended to limit the present disclosure. That is to say, other refrigerants applicable to the air-conditioning system <NUM> are also feasible, and all possible configurations of refrigerants are included within the scope of the present disclosure. As shown in <FIG>, the refrigerant has a saturated liquid line L1 and a saturated vapor line L2, and the saturated liquid line L1 and saturated vapor line L2 intersect at the critical point K. Specifically, the left side of the saturated liquid line L1 indicates that the refrigerant is in a liquid state, the right side of the saturated vapor line L2 indicates that the refrigerant is in a gaseous state, and between the saturated liquid line L1 and the saturated vapor line L2 indicates that the refrigerant is undergoing a phase change and is in a gas-liquid coexisting biphasic state. Ideally, the volume ratio of gaseous refrigerant and liquid refrigerant in the condenser <NUM> and the evaporator <NUM> is <NUM>:<NUM>.

In some embodiments, the refrigerant of the air-conditioning system <NUM> circulates among points A, B, C, and D. To be more specific, when the refrigerant exits the evaporator <NUM> and enters the compressor <NUM>, the refrigerant will be in the state shown at the point A. When the refrigerant exits the compressor <NUM> and is about to enter the condenser <NUM>, the pressure of the refrigerant is increased and the refrigerant will be in the state shown at the point B. When the refrigerant exits the condenser <NUM> and is about to enter the expansion valve <NUM>, the refrigerant will be in the state shown at the point C. Between the point B and the point C, the refrigerant will change from gaseous state to liquid state, and the temperature of the refrigerant remains constant at this time, and is the condensation saturation temperature Tc which is detected by the condensation temperature sensor <NUM> (referring to <FIG>). When the refrigerant exits the expansion valve <NUM> and enters the evaporator <NUM>, the temperature and pressure of the refrigerant drop and the refrigerant is in the state shown at the point D. At this time, a part of the refrigerant evaporates and the refrigerant enters a two-phase state in which gas and liquid coexist. The remaining refrigerant between the point D and the point A will change from a liquid state to a gas state, and the temperature of the refrigerant will remain constant at this time and is the evaporation saturation temperature Te which is detected by the evaporation temperature sensor <NUM> (referring to <FIG>). As a result, under normal circulation, the condensation saturation temperature Tc will be higher than the evaporation saturation temperature Te. Therefore, if the detected evaporation saturation temperature Te is higher than the condensation saturation temperature Tc, it can be determined that the phase change of the refrigerant is abnormal, that is, the refrigerant leakage is likely to occur.

<FIG> illustrates a flowchart of a method <NUM> for detecting the air-conditioning system <NUM> in accordance with some embodiments of the present disclosure. As shown in <FIG>, at step <NUM>, for example, the controller <NUM> instructs the detector <NUM> to detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than the power threshold. The power threshold is close to the input power of the compressor <NUM> at no load, i.e., there is almost no refrigerant in the compressor <NUM>. For example, the aforementioned power threshold may be from about 100W to about 400W, but the present disclosure is not limited thereto. Any suitable power threshold is within the scope of the present disclosure. Specifically, a current sensor (not shown) may be disposed on the controller <NUM> of the air-conditioning system <NUM>. As a result, the input current of the compressor <NUM> may be detected by the current sensor, and the controller <NUM> may calculate the input power according to the input current detected by the current sensor. That is, the controller <NUM> may detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than the aforementioned power threshold. By detecting whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than the power threshold, it can be preliminarily determined whether there is a possibility of refrigerant leakage.

When the detected input power of the compressor <NUM> is lower than the power threshold, the controller <NUM> will obtain the evaporation saturation temperature Te of the evaporator <NUM> of the air-conditioning system <NUM>, and obtain the condensation saturation temperature Tc of the condenser <NUM> of the air-conditioning system <NUM>. At step <NUM>, when the controller <NUM> detects that the evaporation saturation temperature Te is higher than the condensation saturation temperature Tc, the controller <NUM> will determine that an abnormal phase change is occurring in the air-conditioning system <NUM>. Otherwise, when the controller <NUM> detects that the evaporation saturation temperature Te is not higher than the condensation saturation temperature Tc, the controller <NUM> instructs the detector <NUM> to detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than the power threshold. When an abnormal phase change is occurring in the air-conditioning system <NUM>, the volume ratio of the gaseous refrigerant and the liquid refrigerant in the condenser <NUM> and the evaporator <NUM> will not maintain <NUM>:<NUM>.

At step <NUM>, after determining that abnormal phase change (that is, the evaporation saturation temperature Te is greater than the condensation saturation temperature Tc) occurs in the air-conditioning system <NUM>, it is detected whether the compressor <NUM> is operating in the full-speed mode within the second predetermined time. Specifically, the full-speed mode refers to the maximum rotational speed of the compressor <NUM> when the compressor <NUM> is at no load. In some embodiments, the second predetermined time is, for example, from <NUM> minutes to <NUM> minutes, but the present disclosure is not limited thereto. In some embodiments, if the compressor <NUM> is operating in the full-speed mode within the second predetermined time, it goes to step <NUM> to detect whether the compressor <NUM> operates in the full-speed mode for the first predetermined time. For example, the first predetermined time is, for example, from <NUM> minutes to <NUM> minutes, but the present disclosure is not limited thereto. By maintaining the compressor <NUM> in operation in the full-speed mode for the first predetermined time, the risk of misdetermining refrigerant leakage may be reduced, and before the compressor <NUM> is kept in operation in the full-speed mode for the first predetermined time, it may be further confirmed whether the evaporation saturation temperature Te is higher than the condensation saturation temperature Tc.

In particular, the internal air pressure of the normal air-conditioning system <NUM> is usually higher than the atmospheric pressure of the external environment (for example: <NUM> atmosphere pressure). When a pipe in the air-conditioning system <NUM> breaks, most of the gaseous refrigerant in the air-conditioning system <NUM> will leak to the external environment in a short time. Therefore, detecting whether the compressor maintains the maximum rotational speed at no load may determine whether the refrigerant is leaking. However, in order to prevent misdetermination caused by the compressor operating at the maximum speed at no load due to other reasons, it is necessary to further detect whether the compressor maintains the maximum speed at no load for the first predetermined time.

In some embodiments, after the compressor <NUM> is in operation in the full-speed mode within the second predetermined time, continuously detecting (for example, real-time detecting) whether the evaporation saturation temperature Te is higher than the condensation saturation temperature Tc, until the compressor <NUM> operates in the full-speed mode for the first predetermined time. In some other embodiments, the controller <NUM> detects whether the evaporation saturation temperature Te is higher than the condensation saturation temperature Tc at a time interval, and the above time interval is, for example, from <NUM> minutes to <NUM> minutes.

Otherwise, when the compressor <NUM> is not operating in the full-speed mode within the second predetermined time, it returns to step <NUM> to detect whether the evaporation saturation temperature Te is lower than the condensation saturation temperature Tc. If the detected evaporation saturation temperature Te is lower than the condensation saturation temperature Tc, it is determined that the abnormal phase change is transient. After determining that the abnormal phase change is transient, it returns to step <NUM> to detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is greater than the power threshold. If it is detected that the input power of the compressor <NUM> of the air-conditioning system <NUM> is greater than the power threshold, it can be determined that there is no refrigerant leakage in the air-conditioning system <NUM>, as shown in step <NUM>. In some embodiments, when the controller <NUM> detects that the evaporation saturation temperature Te is lower than the condensation saturation temperature Tc, the controller <NUM> may relief the compressor <NUM> from the full-speed mode.

At step <NUM>, the controller <NUM> detects that the compressor <NUM> is maintained in operation in the full-speed mode for the first predetermined time. If the compressor <NUM> operates in the full-speed mode for the first predetermined time, the possibility that the abnormal phase change is transient can be ruled out. As a result, it goes to step <NUM> to determine that the refrigerant of the air-conditioning system <NUM> is leaking. In some embodiments, after determining that the refrigerant of the air-conditioning system <NUM> is leaking, the controller may issue a refrigerant leakage warning to remind users of the refrigerant leakage of the air-conditioning system <NUM>. In this way, users can realize that the refrigerant is leaking, and can repair the air-conditioning system <NUM> in time. In contrast, if the compressor <NUM> is not operating in the full-speed mode for the first predetermined time, it returns to step <NUM> to detect whether the evaporation saturation temperature Te is lower than the condensation saturation temperature Tc.

<FIG> illustrates a flowchart of a method <NUM> for detecting the air-conditioning system in accordance with some embodiments of the present disclosure. As shown in <FIG>, at step <NUM>, for example, the controller <NUM> instructs the detector <NUM> to detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than a power threshold. The power threshold is the input power of the compressor <NUM> at no load, i.e., there is almost no refrigerant in the compressor <NUM>. For example, the aforementioned power threshold may be from about 100W to about 400W, but the present disclosure is not limited thereto. Any suitable power threshold is included within the scope of the present disclosure. Specifically, a current sensor (not shown) may be disposed on the controller <NUM> of the air-conditioning system <NUM>. In this way, the input current of the compressor <NUM> may be detected by the current sensor, and the controller <NUM> may calculate the input power according to the input current detected by the current sensor. Accordingly, the controller <NUM> may detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than the aforementioned power threshold. By detecting whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than the power threshold, it may be preliminarily determined whether there is a possibility of refrigerant leakage.

When the detected input power of the compressor <NUM> is lower than the power threshold, the controller <NUM> will obtain the evaporation saturation temperature Te of the evaporator <NUM> of the air-conditioning system <NUM>, and obtain the condensation saturation temperature Tc of the condenser <NUM> of the air-conditioning system <NUM>. At step <NUM>, when the controller <NUM> detects that the evaporation saturation temperature Te is higher than the condensation saturation temperature Tc, the controller <NUM> will determine that an abnormal phase change is occurring in the air-conditioning system <NUM>. Otherwise, when the controller <NUM> detects that the evaporation saturation temperature Te is not higher than the condensation saturation temperature Tc, the controller <NUM> instructs the detector <NUM> to detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is lower than the power threshold. When an abnormal phase change is occurring in the air-conditioning system <NUM>, the volume ratio of the gaseous refrigerant and the liquid refrigerant in the condenser <NUM> and the evaporator <NUM> will not remain <NUM>:<NUM>.

At step <NUM>, for example, when the compressor <NUM> is operating in the full-speed mode, it may be detected every second predetermined time whether the evaporation saturation temperature Te is lower than the condensation saturation temperature Tc. If the controller <NUM> detects that the evaporation saturation temperature Te is lower than the condensation saturation temperature Tc, it can be determined that the abnormal phase change is transient (such as step <NUM>), and it returns to step <NUM> to continue the above detection steps. Otherwise, if the controller <NUM> detects that the evaporation saturation temperature Te is higher than the condensation saturation temperature Tc, the compressor <NUM> is kept in operation in the full-speed mode, and it goes to step <NUM> to detect whether the compressor <NUM> is operating in the full-speed mode for the first predetermined time. For example, the first predetermined time is, for example, from <NUM> minutes to <NUM> minutes, but the present disclosure is not limited thereto. By keeping the compressor <NUM> in operation in the full-speed mode for the first predetermined time, the risk of misdetermining refrigerant leakage can be reduced. Before the compressor <NUM> is kept in operation in the full-speed mode for the first predetermined time, it can be further confirmed whether the evaporation saturation temperature Te is higher than the condensation saturation temperature Tc.

At step <NUM>, the controller <NUM> detects that the compressor <NUM> is maintained in operation in the full-speed mode for the first predetermined time. When the compressor <NUM> is not kept operating in the full-speed mode for the first predetermined time, it returns to step <NUM> to detect whether the evaporation saturation temperature Te is lower than the condensation saturation temperature Tc. If the detected evaporation saturation temperature Te is lower than the condensation saturation temperature Tc, it is determined that the abnormal phase state change is transient. After determining that the abnormal phase change is transient, it returns to step <NUM> to detect whether the input power of the compressor <NUM> of the air-conditioning system <NUM> is greater than the power threshold. If it is detected that the input power of the compressor <NUM> of the air-conditioning system <NUM> is greater than the power threshold, it can be determined that there is no refrigerant leakage in the air-conditioning system <NUM>, as shown in step <NUM>. In some embodiments, when the controller <NUM> detects that the evaporation saturation temperature Te is lower than the condensation saturation temperature Tc, the controller <NUM> may relief the compressor <NUM> from the full-speed mode.

If the compressor <NUM> operates in the full-speed mode for the first predetermined time, the possibility that the abnormal phase change is transient can be excluded, that is, it goes to step <NUM> to determine that the refrigerant in the air-conditioning system <NUM> is leaking. In some embodiments, after determining that the refrigerant of the air-conditioning system <NUM> is leaking, the controller may issue a refrigerant leakage warning to remind users of the refrigerant leakage of the air-conditioning system <NUM>. In this way, users can realize that the refrigerant is leaking, and can repair the air-conditioning system <NUM> in time.

Claim 1:
A detection method for an air-conditioning system (<NUM>), comprising:
detecting whether an input power of a compressor (<NUM>) of the air-conditioning system (<NUM>) is lower than a power threshold;
the detection method is characterised by:
obtaining an evaporation saturation temperature (Te) of an evaporator (<NUM>) of the air-conditioning system (<NUM>), and obtaining a condensation saturation temperature (Tc) of a condenser (<NUM>) of the air-conditioning system (<NUM>) when the input power is lower than the power threshold;
determining that an abnormal phase change is occurring and operating the compressor (<NUM>) in a full-speed mode when it is detected that the evaporation saturation temperature (Te) is higher than the condensation saturation temperature (Tc);
detecting whether the compressor (<NUM>) operates in the full-speed mode for a first predetermined time when the compressor (<NUM>) is operating in the full-speed mode; and
determining that a refrigerant of the air-conditioning system is leaking if the compressor (<NUM>) operates in the full-speed mode for the first predetermined time.