Clogging detection using electrical characteristics of fan motor

Abstract

Provided herein is an air source heat pump comprising: an air heat exchanger; a motor-driven fan for driving ambient air from an air inlet to an air outlet, the heat exchanger being located in an air flow path between the air inlet and the air outlet; a compressor for compressing a refrigerant and causing it to flow through the air heat exchanger; and a processor programmed to determine whether a blockage or obstruction exists in the air flow path based on a detected operating condition of the fan motor. Also provided is a method performed by a processor of an air source heat pump having an air heat exchanger and a motor-driven fan for driving ambient air from an air inlet to an air outlet, the heat exchanger being located in an air flow path between the air inlet and the air outlet, the method comprising determining whether a blockage or obstruction exists in the air flow path based on a detected operating condition of the fan motor.

Description

Technical Field

[0001] This invention relates to an air source heat pump and an air source heat pump operation method. Background Technology

[0002] According to EU Directive 2012 / 27 / EU, buildings account for 40% of final energy consumption and 36% of CO2 emissions. The European Commission’s 2016 report, “Mapping and Analysis of Heating / Cooling Fuel Deployment (Fossil Fuels / Renewable Energy) Current and Future (2020-2030),” concluded that heating and hot water alone account for 79% (192.5 million tonnes of oil equivalent) of total final energy use in EU households. The European Commission also reported that, “According to Eurostat data from 2019, approximately 75% of heating and cooling still comes from fossil fuels, while only 22% comes from renewable energy sources. To achieve the EU’s climate and energy targets, the heating and cooling industry must significantly reduce energy consumption and fossil fuel use. Heat pumps that extract energy from the air, soil, or water have been identified as potentially significant contributors to addressing this issue. Since only a small number of households have access to bodies of water to support water-based heat pumps, and the cost and space requirements for installing ground-source heat exchangers are very high, installing air-source heat pumps is generally more economical and convenient. Air-source heat pumps are widely considered a better alternative to existing gas-fired central heating boilers.”

[0003] However, air source heat pumps have a drawback that heat pumps extracting energy from water or soil do not: in temperate and colder climates, when the heat pump operates in heating mode (extracting energy from ambient air), the air heat exchanger needs to be defrosted periodically. An air heat exchanger is a heat exchanger that transfers heat from ambient air to a liquid refrigerant in heating mode. It typically consists of a matrix of finned tubes (more broadly called conduits) that receive the cold liquid refrigerant and force ambient air through these tubes using a fan or impeller. In heating mode, because the liquid refrigerant is colder than the ambient air, energy is extracted from the ambient air, causing the liquid refrigerant to vaporize as its temperature rises, while the ambient air temperature drops. Water vapor carried by the ambient air therefore tends to condense on the surface of the air heat exchanger. If the ambient air temperature is low enough, the water condensed on the air heat exchanger surface will freeze into ice. Ice buildup reduces the heat transfer efficiency of air source heat pumps. Severe ice buildup can block the gaps between adjacent pipes in the air source heat pump, obstructing airflow and further reducing efficiency. Therefore, air source heat pumps are configured to intermittently perform a so-called defrost cycle (which essentially involves briefly running the heat pump in cooling mode to release heat from the refrigerant into the environment through the air source heat pump), during which warm refrigerant is introduced into the air source heat pump to melt the ice layer, thereby restoring the efficiency of the air source heat pump. The defrost cycle involves the reverse of the energy extraction cycle typically used in heating mode: the heat pump runs in reverse, transferring energy from inside the house (e.g., from the heated space within the house, from hot water in the space heating system, or from the domestic hot water supply) to the air source heat pump, and then releasing it into the environment. The defrosting process obviously reduces the overall efficiency of the air source heat pump.

[0004] Defrost cycles may occur as frequently as once every 35 minutes, lasting approximately 10 minutes each time. The heat pump processor can be programmed to perform defrost cycles periodically, either based on a fixed cycle or a cycle dependent on environmental conditions (such as ambient temperature and possible humidity), while also considering factors such as the heat load the system needs to provide. In some cases, the heat pump processor may force defrost events that are actually unnecessary. Considering the inherent efficiency loss from performing defrost events, reducing any unnecessary defrost events is clearly beneficial; at the same time, considering the inherent efficiency loss of air-source heat pumps operating with the heat exchanger iced, ensuring that defrost events are performed when actually needed is also necessary.

[0005] Air source heat pumps typically operate in either heating or cooling modes. In heating mode, they extract ambient heat through an air heat exchanger to heat the space, usually providing domestic hot water for residences. In cooling mode, heat is extracted from the residence and dissipated into the environment through the air heat exchanger. For efficient cooling, the cooling mode is typically configured as part of the air conditioning system. Simple heat pump installations, especially those replacing traditional central heating boilers, generally do not have air conditioning functionality. Instead, the heat pump is simply connected to deliver hot water and heated fluid (usually water) to various radiant heat exchange components, such as radiators or underfloor heating systems. In such installations, the air source heat pump may be idle from early spring until late autumn, a period that can last up to six months; or it may only operate to provide hot water, typically for no more than an hour per day. However, domestic hot water can often be heated by other means besides the heat pump, so in such installations, the heat pump is only used during the colder periods of the year, with single periods of idle time potentially lasting several months. Another potential problem with air source heat pumps in such cases is blockage of the airflow path to or from the air heat exchanger. Typically, air source heat pumps have some form of grille or protective mesh at both the air inlet (one or more) and outlet (one or more). This mesh ensures smooth airflow and, more importantly, prevents curious children or other individuals from touching rotating components (such as fan blades), the low-temperature icy surfaces of the air heat exchanger, and the heat pump's electrical system and power supply, ensuring personal safety. If left unattended for months, these air inlets and corresponding internal air passages can become nesting sites for birds or rodents such as bees, wasps, or termites, or become blocked by fallen leaves or plant growth, especially climbing plants like ivy. Such blockages can form rapidly over days or weeks, rather than months, while other blockages caused by children playing, human negligence, or malicious acts can occur within minutes or hours.

[0006] Air source heat pump installers typically advise users to inspect the appearance of the heat pump before restarting it after a long period of inactivity. This helps to identify and remove blockages caused by foreign objects such as fallen leaves before restarting the pump. Installers may also recommend professional maintenance before the first use of the new heating season each year, but this advice is often overlooked. If an air source heat pump operates with its air inlet / outlet partially blocked, its efficiency will be significantly reduced. In some cases, if the heat pump continues to operate with its ventilation channels blocked or partially blocked, or if the fan rotation is obstructed (e.g., due to nesting, insect infestation, or children inserting sticks between the fan blades), the fan or fan motor of the heat pump may be damaged.

[0007] The present invention aims to provide an air source heat pump that can partially or completely alleviate at least some of the defects of existing air source heat pumps. Summary of the Invention

[0008] According to a first aspect, an air source heat pump is provided, including an air heat exchanger, a motor-driven fan for conveying ambient air from an air inlet to an air outlet, the heat exchanger being arranged within an airflow path extending between the air inlet and the air outlet, a compressor for compressing refrigerant and causing the refrigerant to flow through the air heat exchanger, and a processor programmed to determine whether there is an obstruction or blockage in the air inlet, the air outlet, or the airflow path based on detected or determined operating status of the fan motor.

[0009] According to a second aspect, an air source heat pump is provided, including an air heat exchanger, a motor-driven fan for conveying ambient air from an air inlet to an air outlet, the heat exchanger being arranged within an airflow path extending between the air inlet and the air outlet, a compressor for compressing refrigerant and causing the refrigerant to flow through the air heat exchanger, and a processor programmed to determine whether there is an obstruction or blockage in the air inlet, the air outlet, or the airflow path based on detected or determined electrical characteristics of the fan motor.

[0010] In the variation of the first or second aspect:

[0011] Optionally, the fan motor has an associated controller, and the processor is configured to obtain detected operating status from the controller.

[0012] Optionally, the processor may be programmed to perform the determination before attempting to start the compressor.

[0013] Optionally, the processor has at least one operating mode in which the processor is programmed to power on the compressor only when the determination shows no obstruction or blockage, or any obstruction or blockage is below a significant threshold level.

[0014] Optionally, the detected operating state is the electrical characteristics of the motor.

[0015] In a heat pump according to any variation of the first or second aspect, the electrical characteristic may be motor power consumption, and the detected change may be an increase in power consumption or an increase in the rate of change of power consumption.

[0016] In a heat pump according to any variation of the first or second aspect, the electrical characteristics may include one or more of the following: motor drive current, effective duty cycle in a pulse width modulation drive scheme, voltage supplied to the motor, amplitude and / or phase of current pulses applied to the motor.

[0017] In a heat pump according to any variation of the first or second aspect, the electrical characteristic may be the motor drive current, and the detected change may be a decrease in the drive current or a decrease in the rate of change of the drive current.

[0018] In a heat pump according to any variation of the first or second aspect, the processor can access a database of the electrical characteristics of the motor.

[0019] In a heat pump according to any variation of the first or second aspect, the motor may be an electronically commutated motor.

[0020] Optionally, the motor may be coupled to an electronic motor controller, which itself is coupled to the processor.

[0021] Optionally, the electric motor controller and the processor can be coupled via the MODBUS protocol.

[0022] According to a third aspect, a method is provided executed by an air source heat pump processor, the heat pump having an air heat exchanger for delivering ambient air from an air inlet to an air outlet via a motor-driven fan, the heat exchanger being arranged within an airflow path extending between the air inlet and the air outlet, the method comprising determining whether there is an obstruction or blockage in the air inlet, the air outlet, or the airflow path based on detected operating states or electrical characteristics of the fan motor.

[0023] Optionally, in the method according to the third aspect, the fan motor has an associated controller, and the method further includes receiving data of detected operating status from the controller.

[0024] Optionally, the method according to the third aspect further includes: starting the compressor of the heat pump only when the determination shows that there is no obstruction or blockage, or that any obstruction or blockage is below a significant threshold level. Attached Figure Description

[0025] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

[0026] Figure 1 An air-source heat pump is illustrated in heating mode.

[0027] Figure 2 Schematic illustration Figure 1 The air source heat pump operates in defrost mode;

[0028] Figure 3 The illustration schematically depicts a heat pump mounting structure according to an embodiment of the present invention. Detailed Implementation

[0029] Figure 1An air-source heat pump 10 operating in heating mode is schematically illustrated. The main mechanical components of the heat pump are shown, but for clarity, electrical, sensing, and control elements and connections (including the heat pump's controller or processor) are omitted. Starting from the lower right corner of the figure, under the action of the compressor 32, cold liquid refrigerant is pressurized from the liquid receiver 12 along pipe 14, which passes through the lower part of the air heat exchanger 20 and reaches the heating expansion valve 16. Pipe 14 has an open end 15, which is immersed in the liquid refrigerant during use; therefore, the refrigerant supplied from the reservoir 12 to pipe 14 is liquid refrigerant, not vapor.

[0030] In the heating expansion valve 16, the refrigerant flows through a small opening, causing a pressure drop and consequently lowering the boiling point of the refrigerant. Depending on the refrigerant temperature at the expansion valve inlet and the refrigerant pressure at the expansion valve outlet, some of the refrigerant may spontaneously vaporize, resulting in a decrease in refrigerant temperature and causing the refrigerant to leave the expansion valve as a gas-liquid mixture. The refrigerant enters the distributor 18 from the expansion valve 16, where a single input pipe is coupled to multiple output pipes, each of which supplies liquid to the pipes of the air heat exchanger 20.

[0031] A one-way valve 50 is connected in parallel with the heating expansion valve 16, but its direction is configured to allow refrigerant to flow from the distributor 18 to the pipe 14 (the flow direction of the refrigerant during cooling mode) and to prevent refrigerant from flowing from the pipe 14 to the distributor. Therefore, in heating mode, the refrigerant must flow through the heating expansion valve 16 to reach the distributor 18. As understood by those skilled in the art, the heating expansion valve 16 (like other expansion valves in a heat pump) is controlled by the heat pump processor to achieve a target refrigerant superheat value suitable for the current operating conditions.

[0032] A filter dryer 51 may be installed in the flow path leading to the heating expansion valve 16. If the filter dryer 51 is present, the flow through the one-way valve 50 during cooling and defrosting will also bypass the filter dryer 51.

[0033] In one variant, distributor 18 may include three flow paths: a single inlet pipe 17 with a small internal fixed orifice (not shown), multiple outlet pipes (denoted by reference numeral 19), and an internal bypass pipe. In heating mode, refrigerant flows through the heating expansion valve 16 to the single inlet pipe 17 of distributor 18, and then flows out through the multiple outlet pipes 19 after passing through the small internal fixed orifice. In heating mode, there is no flow through the internal bypass pipe. Refrigerant expansion is achieved through the heating expansion valve and the fixed orifice. In cooling mode, refrigerant can flow out from the multiple outlet pipes 19 and through the internal bypass pipe, bypassing the internal fixed orifice and the heating expansion valve 16 via the check valve 50, such that the influence of the heating expansion valve 16 and the internal fixed orifice of distributor 18 is negligible in cooling mode. In another variant, the distributor may not have the small internal fixed orifice and the internal bypass pipe.

[0034] Air heat exchanger 20 is schematically shown as containing only four ducts running through it, but in reality, more such ducts are provided, and each duct is typically equipped with heat-conducting fins to enhance heat transfer between the air and the refrigerant within the duct. Air heat exchanger 12 includes (or is coupled to) a fan 24 that drives ambient air to flow through air heat exchanger 20.

[0035] In heating mode, the refrigerant within the air heat exchanger 20 is heated by absorbing energy from the ambient air, transforming it into vapor. This vapor can be further heated by absorbing energy from the air, potentially forming superheated steam. The vaporized refrigerant exits the air heat exchanger 20 through a collector (or manifold) 26, which connects to a return pipe 28 supplying the first port (port 1) of a four-way valve 30. The vaporized refrigerant exits the four-way valve 30 through port 2, flowing from there to the compressor 32. In the compressor, the heated, vaporized refrigerant, entering at low pressure, is compressed into high-pressure vapor, with the refrigerant temperature further increasing during compression. The refrigerant returns from the compressor 32 through the four-way valve 30, enters through port 3, and exits through port 4, which supplies the heat exchanger matrix (not shown) in the heating system heat exchanger 34. As shown in the figure, the heat exchanger 34 of the heating system can be a heat exchanger for a heating system in which energy from the hot refrigerant is transferred to water (or some other suitable operating fluid in the case of space heating), for example, for space heating through a central heating system, or for providing hot water for domestic and industrial use. The hot refrigerant enters the heat exchanger 34 from port 36 and exits as a cooling refrigerant from port 38 after condensation. Water for heating enters from port 40 on the colder side of the heat exchanger 34 and exits from port 42 on the hotter side of the heat exchanger 34. Inside the heat exchanger 34, the refrigerant condenses from vapor to liquid, releasing heat to the water in the water circuit of the heat exchanger 34. The cooled liquid refrigerant flows from port 38 to a one-way valve 54, which is configured to allow the refrigerant to flow from the heat exchanger 34 to the receiver 12. Therefore, the one-way valve 54 serves as a bypass to another expansion valve 44, which is used to expand the refrigerant as it flows from the receiver 12 to the heating system heat exchanger 34 during cooling mode operation (and therefore also during defrosting of the air heat exchanger). In heating mode, the refrigerant can flow through the one-way valve 54, bypassing the cooling expansion valve 44 with minimal resistance, making the effect of the cooling expansion valve 44 negligible in heating mode. The liquid refrigerant then flows back to the receiver 12, the starting point of this process. It should be understood that the heating system heat exchanger 34 can also use refrigerant to heat air (e.g., for heating a warm air space) instead of refrigerant to heat water, but the basic principle remains the same.

[0036] Figure 1It also includes another heat exchanger 46, which receives refrigerant from refrigerant line 14 via another expansion valve 48. This other heat exchanger 46 is optional, but preferably configured to cool (and control the temperature) the electrical inverter (not shown) that powers the compressor and various other electrical components and systems of the heat pump. This other heat exchanger 46 may include a radiator, which is thermally coupled to the inverter and optionally to other electronic and power components of the heat pump. The cooling provided by this other heat exchanger 46 helps ensure the proper functioning of the inverter and other electronic components, extending their lifespan, while recovering heat that might otherwise be wasted and transferring it to the refrigerant, which is then delivered to the compressor 32, thereby further improving heat pump efficiency. The inverter cooling expansion valve and the function of the inverter cooling heat exchanger, as well as the flow direction through it, are independent of and unaffected by the operating mode (i.e., heating, cooling, defrosting). The inverter cooling expansion valve is controlled by the heat pump processor to regulate the state of the refrigerant flowing through the inverter cooling heat exchanger to achieve the desired cooling effect, such as reaching a target value for the inverter drive temperature.

[0037] like Figure 1 The heat pump shown operates in cold weather (e.g., below approximately 10 degrees Celsius) in temperate climates, where water vapor in the ambient air may condense on the air heat exchanger 20 and subsequently freeze. Ice buildup on the air heat exchanger 20 obstructs airflow and reduces the efficiency of energy transfer from the ambient air to the refrigerant. This heat pump typically includes mechanisms for detecting ice buildup, or mechanisms for detecting anticipated icing conditions, or some other mechanism to ensure timely defrosting, and has a configured (e.g., programmed) processor to enable the heat pump to enter defrost mode as needed. Throughout this specification, the reference to "processor" refers to a processor or controller (e.g., a microcontroller or microprocessor) configured or programmed to perform relevant functions and operations. This processor or controller typically includes and / or is coupled to a memory device storing relevant code, instructions, programs, algorithms, and data to enable the processor to perform relevant operations, functions, methods, and processes.

[0038] although Figure 1 Not shown, but preferably a drip tray is provided below the air heat exchanger 20 to collect condensate when the heat pump is running in defrost or heating mode, for the reasons stated above.

[0039] A sensor 31 can be installed at the inlet of the compressor 32 to measure the temperature and pressure of the refrigerant. Based on the values ​​obtained by these sensors 31, the heat pump's processor or controller can determine the state of the refrigerant at or immediately upstream of the compressor inlet, particularly its superheat.

[0040] Figure 2 and Figure 1Correspondingly, the heat pump shown operates in cooling mode (e.g., for a residence using a cooling heat pump service), not heating mode, which is also used as a defrosting mode. In cooling mode, the refrigerant flows in the opposite direction to heating mode, a reversal achieved by controlling the four-way valve 30, causing the refrigerant received at port 32 outlet to flow to port 1 instead of port 4. Therefore, the refrigerant heated by compressor 32 does not subsequently flow to heat exchanger 34, but to collector (or manifold) 26, and then into air heat exchanger 20. By supplying hot refrigerant to the air heat exchanger, the ice buildup is melted. The cooled refrigerant leaves air heat exchanger 20 through distributor 18, and then returns to liquid container 12 via one-way bypass valve 50 and subcooler.

[0041] The expanded refrigerant flowing from the liquid receiver 12 flows out along pipe 52. Pipe 52 has an open end 53 that is immersed in the liquid refrigerant during use, so that the refrigerant supplied from the receiver 12 to pipe 52 is liquid refrigerant, not vaporized refrigerant. The refrigerant from the receiver 12 flows along pipe 52 through the refrigeration expansion valve 44, and from there to port 38 of the heat exchanger 34 of the heating system. In cooling mode, the refrigerant does not flow through the bypass pipe due to the position and orientation of the one-way valve 54. The expansion of the refrigerant is achieved through the refrigeration expansion valve 44. In the expansion valve, the refrigerant flows through a small opening, causing a pressure drop, which in turn lowers the boiling point of the refrigerant. Depending on the temperature of the refrigerant at the inlet of the expansion valve and the pressure of the refrigerant at the outlet of the expansion valve, some of the refrigerant may spontaneously vaporize, causing the refrigerant temperature to drop (leaving the refrigerant in a gas-liquid mixture state when leaving the expansion valve). The expansion valve can be controlled by the heat pump processor based on the pressure on the compressor 32 input side and data from the temperature sensor 31.

[0042] As the expanded refrigerant flows through the heat exchanger 34 of the heating system, it absorbs heat from the hot water within the heat exchanger (water flows from port 40 to port 42 during use) and vaporizes. The heated, vaporized refrigerant leaves the heat exchanger through port 36, flows to port 4 of the four-way valve 30, and exits through port 2. The refrigerant vapor flows from port 2 of the four-way valve 30 to the compressor 32. It is crucial that the refrigerant enters the compressor in vapor form, as receiving liquid refrigerant could damage the compressor. The compressor compresses the refrigerant, further increasing its temperature, and delivers it to port 3 of the four-way switch 30. The refrigerant exits the four-way switch through port 1. Because the compressor 32 operates at a consistently low pressure on its input side, in cooling mode, as in heating mode, the refrigerant continues to flow through the inverter's heat exchanger 46 and to the compressor 32 under the control of the heat pump processor.

[0043] As those skilled in the art will recognize, in addition to the methods described above, other defrosting techniques can be employed to defrost the air heat exchanger 20, such as using an electric heater associated with the heat exchanger 20. Such or other techniques can be used as… Figure 2 Use alternatives or supplementary solutions to the technology.

[0044] As mentioned earlier, blockages or obstructions in the airflow paths (one or more) through an air-source heat pump can occur not only due to icing of the air heat exchanger when the heat pump is operating in heating mode, but also during periods of inactivity (e.g., late spring to late autumn in temperate climates, if the heat pump is not used for air conditioning or providing hot water). A method is needed to automatically detect such blockages and obstructions.

[0045] According to various aspects of the invention, such methods are implemented by monitoring the electrical operating state or electrical characteristics of a heat pump fan motor. Thus, a first aspect provides an air-source heat pump comprising an air heat exchanger, a motor-driven fan for conveying ambient air from an inlet to an outlet, the heat exchanger being arranged within an airflow path extending between the inlet and outlet, a compressor for compressing refrigerant and flowing refrigerant through the air heat exchanger, and a processor programmed to determine, based on detected fan motor operating states, whether there is an obstruction or blockage at the inlet, outlet, or airflow path.

[0046] Any obstruction or blockage of the air inlet, outlet, or airflow path, regardless of the cause, can result in the fan motor consuming more or less power, or the rate of change in power drawn may increase or decrease due to variations in drive conditions. By characterizing these changes in electrical operating conditions, the presence of obstruction or blockage can be determined, and its severity can be assessed based on the detected changes in electrical characteristics. This determination allows for the detection of obstructions both when starting a heat pump after a long period of inactivity and when obstructions arise during normal operation due to the need for defrosting the air heat exchanger.

[0047] Upon startup, regardless of whether the heat pump has been idle for an extended period, the processor can be configured to compare the electrical operating status of the fan motor (e.g., power drawn and / or the rate of change of power drawn) with stored values ​​representing normal operating conditions and obstructions of varying locations and severity, thereby determining the presence and characteristics of any obstruction. This determination is appropriate to be performed before the processor attempts to start the heat pump compressor, thus avoiding high / low pressure trips (potentially causing damage) and preventing energy waste by running the compressor when the heat pump is not operating effectively due to, for example, obstructed airflow paths. The processor can be programmed to issue error status signals based on obstructions determined according to the fan motor operating status, such as sending messages via user devices like smartphones, displaying information on control panels, displaying information or warning lights on the heat pump unit, and / or issuing audible (e.g., voice) warnings.

[0048] Figure 3 The diagram schematically illustrates a heat pump 310 according to an embodiment of the invention, particularly an arrangement of components supporting a heat pump processor 300 in determining the need for a defrost cycle and determining the duration of the defrost cycle. The heat pump has a housing 311, inside which are arranged an air heat exchanger matrix 322, one or more fans 324 with associated drive motors 304, a processor 300, and (optionally) a heating system heat exchanger 334; although the heating system heat exchanger can be remotely installed, for example, within a house (more broadly, a residence) 335, replacing a gas boiler that has been replaced by the heat pump. The processor 300, with an associated memory 302 (storing software instructions, etc., for controlling processor operation), is operatively connected to a valve device 330 for controlling the flow of refrigerant within the heat pump, particularly switching the flow direction through the air heat exchanger matrix between heating mode operation and defrost mode operation. As previously mentioned, the valve device 330 may comprise a four-way valve or a suitable combination of simpler valves 330A, 330B, and 330C. The processor 300 is also operatively connected to a motor 304 that drives a fan 324, the fan's rotation driving (drawing in or pushing) ambient air through an air heat exchanger matrix 322. The processor can be configured to control the fan motor or to obtain motor power consumption information from appropriate circuitry, such as current draw from the motor 304, or the effective duty cycle, supply voltage, amplitude and / or phase of the current pulse applied to the motor, or a combination of these parameters, in a pulse-width modulation drive scheme.

[0049] Motor 304 is preferably an electronically commutated motor (EC motor), also known as a brushless DC motor (BLDC motor) powered by a direct current (DC) power supply. This motor can switch the DC current flowing to the motor windings via an electronic controller 305 (typically located within the fan motor housing), generating a magnetic field that effectively rotates in space, causing the permanent magnet rotor to rotate. The controller can adjust the phase and amplitude of the DC current pulses, and / or employ some form of pulse width modulation and / or voltage control to regulate the motor speed and torque. This control system can replace the mechanical commutators (brushes) used in many traditional motors. The fan motor controller itself is regulated by the heat pump controller and feeds back information to the heat pump controller; the heat pump controller provides the fan speed demand signal based on the heat pump operating conditions. Various communication methods exist between the fan controller and the heat pump controller (analog signals, PWM, MODBUS, etc.), with the MODBUS protocol being preferred because it supports bidirectional communication, allowing information from the fan controller (e.g., fan motor current, power, voltage, pulse amplitude and / or duration and / or frequency) to be obtained from the fan controller and used by the heat pump controller.

[0050] Although Figure 3 The air heat exchanger matrix 322 is located downstream of the fan 324 and its motor 304. In practical applications, the fan (preferably including its motor) can be placed downstream of the air heat exchanger matrix 322, and the fan is preferably arranged to draw air through the air heat exchanger matrix 322 rather than push air through the air heat exchanger matrix.

[0051] The processor 300 is also operatively connected to a temperature and humidity sensing device 306, which detects the ambient temperature and humidity at the location of the air heat exchanger 320. The processor 300 and the air heat exchanger matrix can be housed in an integrated structure or in separate structures / housings, for example, the processor can be located within the internal housing of a heat pump-heated residence 335, while the air heat exchanger 320 can be located in a separate housing outside the residence 335. In the latter case, the housing for housing the air heat exchanger 320 may also contain a processor or controller (such as a microcontroller), which is controlled by or works in conjunction with a processor within the residence 335. Also in the latter case, the processor within the residence can communicate with components and systems in the external housing or their associated components and systems via wired or wireless means (e.g., using protocols such as Matter, Bluetooth, Zigbee, Wi-Fi, 5G, etc.). The processor 300 is operatively connected to a control device 340 that controls the heating system of the residence 335. The control device may include one or more thermostats 342 and a controller 344 operable to control the heating system, for example, by setting the start and stop times for heating periods. The controller 344 may form part of a "smart home" or home automation system that can be used to schedule the operation of heating systems (such as space heating and domestic hot water), security monitoring systems, lighting systems, and other equipment. Such home automation systems can be programmed to control the operation of various systems and subsystems (such as space heating and / or hot water heating) based on occupancy data provided by the resident, or from schedule / planning information related to resident activities and planned presence. The home automation system may also use presence status information provided by motion sensors or the opening and closing of doors (interior and exterior doors, which also support security monitoring systems), or from presence status information triggered by electrical switches, to track actual occupancy. The heat pump processor 300 can use such actual and predicted occupancy data, along with planned heating time data, to determine whether to perform a defrost event; for example, if it is determined that the air heat exchanger is suitable for defrosting, but the heating controller 344 plans to shut down the heating system, the processor 300 may decide not to perform the defrost event because the heat pump will no longer need to provide heat in a short time (e.g., less than an hour or less than half an hour).

[0052] Processor 300 is operatively connected to a camera (such as a video camera) and / or other optical sensors 308 to detect icing on the air heat exchanger matrix 322; if a camera is used, image processing capabilities and, optionally, machine learning capabilities based on signal / image analysis can be added to detect icing conditions and defrosting needs. Processor 300 is operatively connected to the Internet 350 to access a (local or hyperlocal) weather forecast source 360 ​​and to a system backend 312 managed by the heat pump manufacturer / supplier or installer. Processor 500 can utilize data from the weather forecast source 360 ​​and be configured to respond to severe weather conditions, such as those that may accelerate or exacerbate frost or icing on the air heat exchanger, by limiting (reducing) the maximum output power of the heat pump (i.e., reducing the heat extracted from the air, thereby slowing icing; for example, a heat pump controller can reduce energy extraction from 16kW to 10-12kW, reducing heat extraction by approximately 25%–50%), or by lowering the superheat setpoint, thereby supplying refrigerant to the air heat exchanger at a higher temperature to reduce icing. In this way, the heat pump can prepare for upcoming severe weather conditions and potentially reduce the frequency of defrost events. Alternatively, particularly severe weather may cause the heat pump to increase the frequency of its defrost cycles or switch to supplying hot refrigerant vapor to the air heat exchanger instead of initially relying solely on shutting down certain components of the air heat exchanger. The system backend 312 can also be configured to provide advance notification of weather events, for example, based on reports from other heat pumps installed in the same adjacent area, or from other heat pumps installed in an area experiencing an approaching front that is moving towards the location of this heat pump. The system backend 312 can also provide necessary firmware upgrades, respond to "event alarms," ​​such as by detecting system or component failures, or respond to system / component failure reports, for example, by dispatching technicians or service personnel, along with the necessary replacement spare parts and maintenance consumables.

[0053] The processor 300 can be configured to distinguish between blockages or obstructions caused by frost buildup on the air heat exchanger and blockages caused by other reasons (such as leaf accumulation, or partial or complete blockage of the air inlet or outlet) based on information from the temperature and humidity sensor 306, information from external meteorological sources (such as online meteorological resources), and the recent operating history of the heat pump. These information sources can supplement the information from the system camera 308 and information from the system backend (which can provide relevant data upon request), such as information related to the likelihood of frost buildup, and / or the operating status information of other air source heat pumps around the equipment installation site, which are also supported by the system backend 312.

[0054] Processor 300 can be configured to detect blockages (such as frost) in the air heat exchanger based on characteristic changes in fan motor power consumption features, such as current consumption, rate of change of current consumption, and effective duty cycle in a pulse-width modulation (PWM) drive scheme. An increase in fan motor power consumption (e.g., an increase detected based on increased current consumption, increased supply voltage, or increased effective duty cycle in a PWM drive scheme) may indicate that the fan motor needs to exert more effort to drive airflow through the air heat exchanger, which could be due to partial or complete blockage of the air heat exchanger. The detected increase in power consumption may also be associated with specific environmental factors (typically temperature and humidity, such as relative humidity), and the rate of increase may be of significant reference value. Conversely, blockage or obstruction may, in some cases, lead to a decrease in current draw. Therefore, the processor can be effectively configured to apply machine learning based on these factors to determine whether the detected increase / decrease in power consumption may originate from ice or snow accumulation on the air heat exchanger, or other reasons (such as leaves or other debris accumulating at the air inlet of the housing housing the air heat exchanger). In the latter case, the processor can be configured to generate an alarm indicating the need to clean the air intakes to the homeowner / occupant (and simultaneously to the system backend 312). This alarm can be sent by the system backend 312, for example, via push notification to the user's device, or even via automated phone, email, or letter. The processor 300 can be configured to detect and record the power consumption of the fan motor 304 during initial installation, using it as baseline data for comparison of subsequent power consumption values; or to be pre-programmed before installation, for example, based on machine learning or empirical testing conducted during heat pump development. Continuous (continuous or periodic) monitoring of fan power consumption characteristics may also reveal maintenance needs, such as cleaning the air intakes (one or more), removing pests (e.g., insect or rodent nests), or replacing a damaged fan or fan motor. The air inlets (one or more) and / or outlets (one or more) of a heat pump may be blocked by external obstructions (such as towels or clothing covering the inlets, equipment such as paddleboards or surfboards, or building materials piled up at one or more inlets or outlets), or internal obstructions (such as insect nests, rodent burrows, or other debris caused by insect or rodent activity, or accumulation of fallen leaves or plant debris) that may impede the normal airflow path between the air inlets (one or more) and outlets (one or more). According to various embodiments of the present invention, the heat pump's processor can detect and identify any of the aforementioned obstructions as long as they reach a significant level.

[0055] Similarly, the processor can detect successful clearing of blockages, such as the completion of defrosting in an air heat exchanger, by observing characteristic changes in the fan motor's power consumption characteristics (e.g., reduced or potentially increased current consumption, decreased or potentially increased effective duty cycle in a pulse-width modulation drive scheme, supply voltage, amplitude / phase of the current pulse applied to the motor, or a combination of these factors). However, it should be understood that effective unblocking of the heat exchanger can actually lead to increased power consumption, for example, if the fan has been under-supplied for an extended period. Therefore, observing the fan motor's operating status under different test conditions is crucial for appropriately programming the processor to optimally detect the air heat exchanger's status based on the motor's drive characteristics, thereby enabling optimized control.

[0056] The location of any blockage or obstruction in the airflow path through the heat pump's air heat exchanger can affect the fan's operating state, thereby altering the fan motor's electrical state / characteristics. For example, partial or complete blockage of the upstream airflow path (whether outside or inside the heat pump housing) may lead to insufficient air supply to the fan, meaning a reduced load on the fan motor, potentially increasing fan speed and lowering power consumption. A similar partial or complete blockage of the downstream airflow path (whether inside or outside the heat pump housing) may require the fan motor to operate at a higher load, potentially increasing power consumption. The fan's aerodynamic characteristics and the characteristics of the upstream and downstream airflow paths affect the fan's operating state and fan motor characteristics under different blockage conditions. Therefore, it is desirable to determine the fan motor's operating state and characteristics under normal operating conditions and various foreseeable blockage conditions before mass production (e.g., under normal operating conditions and different foreseeable blockage conditions), thereby determining electrical characteristics (e.g., learned through learning) that characterize the different nature and location of various obstacles for programming the processor 300. The heat pump processor 300 may also possess some machine learning capabilities to perform field-adaptive adjustments, such as based on engineer field inspection feedback, user input, or data downloaded from a remote control center.

[0057] As previously described, processor 300 is preferably operably connected to controller 340 of the heating system (space heating and / or hot water supply system) of the residence 335 served by the heat pump. Therefore, processor 300 can utilize status information and the heating system schedule to determine whether to take action regarding defrosting suitability. If the residence is equipped with a home automation system 344, processor 300 is preferably operably coupled to this system 344 so that occupancy data, occupant schedules, and other factors are considered when the processor controls the heat pump.

[0058] Alternatively, the processor 300 may be configured to detect icing on the air heat exchanger based on a detected pressure difference across the air heat exchanger, specifically the difference between pressure measured, for example by a first pressure sensor 370, inside the housing of the air heat exchanger (on the "upstream" side of the air heat exchanger), and pressure measured, for example by a second pressure sensor 372, outside the housing. A fan associated with the air heat exchanger may be configured to draw air into the housing through one or more inlets 480 located away from the air heat exchanger, exhaust the air from the housing via or through the air heat exchanger, and ultimately exit from the housing outlet; that is, the fan is positioned upstream of the air heat exchanger, effectively pushing air above the downstream air heat exchanger. Alternatively, the air heat exchanger may be positioned on the fan's inlet side, with the fan downstream of the air heat exchanger, so that the fan draws air into the housing through the air heat exchanger.

[0059] The accuracy of differential pressure detection technology may be affected by the location of the fan upstream or downstream of the air heat exchanger, so it may not be a reliable means of detecting blockages (such as ice buildup) in some cases, and its accuracy depends on the specific configuration chosen.

[0060] In any case, the processor 300 may also utilize information provided by the heating system controller 340 and / or the home automation system 344 when determining whether to perform a seemingly necessary defrosting event.

[0061] If the fan motor has an associated fan motor controller, the processor 300 can obtain fan motor operating status information from the fan motor controller, rather than directly detecting the fan motor operating status. The fan motor controller can be configured (e.g., programmed) to periodically or continuously update the processor 300 with information related to fan motor power consumption and / or other operating characteristics. The fan motor controller can selectively report to the processor 300 based on considerations of the fan motor operating status and all (or some) of the motor drive factors.

[0062] The fan motor controller (which can be an electronically commutated motor or a non-electronically commutated motor) is programmable or configurable to control the fan motor speed, such as maintaining a specific speed (X rpm) or keeping the speed within a specific range (Y to Z rpm). It can also be additionally or alternatively programmed or configured to control the fan motor to achieve a specific fan speed-up rate, or to control the fan speed-up rate within a specified range, such as when the fan accelerates from a standstill or zero speed (or low speed state) to a desired or target fan speed or fan speed range. The controller is programmable or configurable to achieve and maintain differentiated fan speeds or speed ranges based on different control states of the heat pump; for example, by issuing commands from the heat pump processor, such as heat pump power setting levels and / or heat pump operating modes (heating, cooling, defrosting, etc.). To control the fan speed and / or fan speed-up rate, the controller can adjust one or more of several variables, such as the pulse width and / or effective duty cycle in a pulse width modulation drive scheme, the current and / or voltage supplied to the motor, and the amplitude and / or phase of the current pulse applied to the motor. The fan motor controller can receive motor speed information from one or more sensors, and / or determine the speed based on information derived from the motor's electrical characteristics / demands and / or operating status, thereby determining the rate of change of speed. If there is no independent fan motor controller, the heat pump processor can be programmed or configured to perform the relevant functions of the aforementioned fan motor controller. If a dedicated fan motor controller is provided, it can be programmed or configured to provide the heat pump processor with information about the motor's speed, rate of increase in speed, and / or electrical characteristics / demands and / or operating status. Such information transmission can be continuous or periodic, and can be performed automatically or triggered upon request by the heat pump processor.

[0063] It is important to understand that detecting blockages / obstructions during startup and detecting defrost cycle requirements are at different levels. The heat pump processor can be configured to execute only one method or both. Furthermore, depending on the selection or requirements, any variation of either method can be combined with any variation of the other method.

[0064] In some cases, air source heat pumps may preferably be configured with multiple motor-driven fans. For clarity and simplicity, the preceding discussion has focused primarily on the control of a single-motor-driven fan, but it should be understood that the aforementioned methods and system principles are equally applicable to multi-motor configurations.

[0065] While differential pressure detection of air heat exchanger blockage is feasible, we have found that detecting blockage based on the electrical operating status or characteristics of the fan motor is generally more reliable and does not require the use of a sensitive pressure sensor (which is often less reliable).

[0066] Although we have discussed and described blockage detection based on changes in the electrical characteristics or operating conditions of the fan motor, it should be understood that blockage detection can also be based on motor torque measurement or (one or more) fan blade strain measurement. Current strain measurement technologies are relatively expensive, which may hinder their application in residential heat pump installations. However, such methods may be cost-effective in more expensive installation scenarios, and as deployment costs decrease, even residential heat pump installations may gradually become cost-effective. Torque measurement technology is currently more economically attractive than strain measurement technology and is more likely to be favored in the short term, especially for more expensive installation scenarios. In the long term, expected cost reductions will make this method increasingly attractive. However, in the near term, blockage detection based on the electrical characteristics or operating conditions of the fan motor is likely to remain the most cost-effective of the three methods. It should be understood that the inventive concept of this invention still encompasses the application of these three detection technologies.

Claims

1. An air source heat pump, comprising: Air heat exchanger; An electric motor drives a fan to deliver ambient air from an air inlet to an air outlet, and the heat exchanger is arranged within an airflow path extending between the air inlet and the air outlet. A compressor, which is used to compress the refrigerant and cause the refrigerant to flow through the air heat exchanger; as well as, A processor programmed to determine whether there is an obstruction or blockage in the air inlet, the air outlet, or the airflow path based on the detected operating state or electrical characteristics of the fan motor.

2. The heat pump of claim 1, wherein the fan motor has an associated controller, and the processor is configured to acquire data of detected operating status or electrical characteristics from the controller.

3. The heat pump of claim 1 or 2, wherein the processor is programmed to perform the determination before attempting to start the compressor.

4. The heat pump of claim 2 or 3, wherein the processor has at least one operating mode in which the processor is programmed to power the compressor only when the determination indicates that there is no obstruction or blockage, or that any obstruction or blockage is below a significant threshold level.

5. The heat pump of claim 1, wherein the electrical characteristic is motor power consumption, and the detected change is an increase in power consumption or an increase in the rate of change of power consumption.

6. The heat pump of claim 1, wherein the electrical characteristic refers to motor power consumption, and the detected change is a decrease in power consumption or a decrease in the rate of change of power consumption.

7. The heat pump of claim 1, wherein the electrical characteristics include one or more of the following: motor drive current, effective duty cycle in a pulse width modulation drive scheme, voltage supplied to the motor, amplitude and / or phase of current pulses applied to the motor.

8. The heat pump as claimed in any of the preceding claims, wherein the processor is capable of accessing a database of the electrical characteristics of the motor.

9. The heat pump as claimed in any of the preceding claims, wherein the motor is an electronically commutated motor.

10. The heat pump of claim 9, wherein the motor is coupled to an electronic motor controller, the electronic motor controller itself being coupled to the processor.

11. The heat pump of claim 10, wherein the electronic motor controller is coupled to the processor via the MODBUS protocol.

12. The heat pump as claimed in any of the preceding claims, wherein the processor is programmed to provide a notification or signal when it is determined that there is an obstruction or blockage in the airflow path.

13. The heat pump of claim 12, equipped with wired or wireless internet access, wherein the processor is programmed to send a notification to a user device when it is determined that there is an obstruction or blockage in the airflow path.

14. The heat pump as claimed in any of the preceding claims, wherein the processor is further programmed to determine the defrosting requirement of the air heat exchanger based on detected changes in the electrical characteristics of the fan motor.

15. The heat pump of claim 14, wherein the electrical characteristic used to determine the defrosting requirement of the air heat exchanger is motor power consumption, and the detected change is an increase in power consumption or an increase in the rate of change of power consumption.

16. The heat pump of claim 14, wherein the electrical characteristic used to determine the defrosting requirement of the air heat exchanger is motor power consumption, and the detected change is a decrease in power consumption or a decrease in the rate of change of power consumption.

17. The heat pump of claim 14, wherein the electrical characteristics used to determine the defrosting requirement of the air heat exchanger include one or more of the following: motor drive current, effective duty cycle in a pulse width modulation drive scheme, voltage supplied to the motor, amplitude and / or phase of current pulses applied to the motor.

18. The heat pump of any one of claims 14 to 17, wherein the processor is further programmed to consider the one or more other factors before initiating an air heat exchanger defrost event based on determined demand and one or more other factors.

19. The heat pump of claim 18, wherein the heat pump serves a residence, and the other factors include one or more of the following: predicted energy demand, residence occupancy, predicted changes in occupancy, occupant schedules or appointments, historical patterns of occupancy and / or user behavior, and weather forecast data.

20. The heat pump of claim 19, wherein the processor of the heat pump is operatively connected to a home automation system.

21. The heat pump according to any one of claims 14 to 20, wherein the processor is capable of accessing a database of the electrical characteristics of the motor.

22. A method executed by a processor of an air source heat pump, the air source heat pump having: Air heat exchangers; and, A motor drives a fan to deliver ambient air from an inlet to an outlet, the heat exchanger being arranged within an airflow path extending between the inlet and the outlet, the method comprising: Based on the detected operating status or electrical characteristics of the fan motor, determine whether there is any obstruction or blockage at the air inlet, the air outlet, or the airflow path.

23. The method of claim 22, wherein the fan motor has an associated controller, and the method further includes receiving data of detected operating status from the controller.

24. The method of claim 22 or 23, the method further comprising comparing the detected drive current value with one or more stored drive current reference values.

25. The method of any one of claims 22 to 24, the method further comprising starting the compressor of the heat pump only when the determination indicates that there is no obstruction or blockage, or that any obstruction or blockage is below a significant threshold level.

26. The method of any one of claims 22 to 25, the method further comprising providing a notification or signal when it is determined that there is an obstruction or blockage in the airflow path.

27. The method of claim 26, wherein the notification is a notification sent to a user equipment, such as a wireless transceiver unit (WTRU).

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