Control method of heat pump unit, heat pump unit and storage medium

Abstract

The invention relates to a control method of a heat pump unit, the heat pump unit and a storage medium. The method comprises the steps that air inlet parameters, air outlet parameters and operation parameters of the heat pump unit are obtained; based on the air inlet parameters, the air outlet parameters and the operation parameters, the input power of the heat pump unit, the heating capacity generated in unit time in the heating interval duration and the total heating capacity and total power consumption in the whole defrosting period are determined, and the whole defrosting period comprises the heating interval duration and the defrosting interval duration; determining a first energy efficiency ratio of the heat pump unit in a non-defrosting operation mode according to the input power and the heating capacity, and determining a second energy efficiency ratio of the heat pump unit in a defrosting operation mode according to the total heating capacity and the total power consumption; and the first energy efficiency ratio and the second energy efficiency ratio are compared, and the operation mode of the heat pump unit is determined according to the comparison result. In this way, the operation mode with the high energy efficiency can be intelligently selected for operation, and therefore the overall energy efficiency of the heat pump unit is improved.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to a control method for a heat pump unit, a heat pump unit, and a storage medium. Background Technology

[0002] Currently, when heat pump units are heating, if the outdoor temperature is low, frost will form on the surface of the fins. This frost layer will affect air circulation and heat exchange, reducing the efficiency of the heat pump unit. Therefore, the fins need to be defrosted periodically. During defrosting, the heat pump unit needs to absorb heat from the air conditioning hot water and release heat back to the fins to melt the frost into water for defrosting. Therefore, the heat pump unit needs to absorb heat from the water system during defrosting, which will cause a decrease in heating capacity.

[0003] In existing technologies, heat pump units can operate in either a non-defrosting or defrosting mode in ambient temperature ranges prone to frosting (such as +1℃ to +5℃). In non-defrosting mode, heating capacity is stable with no ineffective heat loss during defrosting, but a higher fan speed and lower compressor frequency are required. In defrosting mode, the negative heating capacity is offset by defrosting, but a lower fan speed and higher compressor frequency can be used. Therefore, how to intelligently select the most energy-efficient operating mode for the heat pump unit has become a pressing technical problem to be solved. Summary of the Invention

[0004] This application provides a control method for a heat pump unit, a heat pump unit, and a storage medium to solve the problem that existing heat pump units cannot intelligently select the most energy-efficient operating mode, resulting in low energy efficiency.

[0005] In a first aspect, embodiments of this application provide a control method for a heat pump unit, the method comprising: Obtain the inlet air parameters, outlet air parameters, and operating parameters of the heat pump unit; Based on the air intake parameters, air outlet parameters, and operating parameters, the input power of the heat pump unit, the heat output per unit time during the heating interval, and the total heat output and total power consumption during the entire defrosting cycle are determined. The entire defrosting cycle includes the heating interval duration and the defrosting interval duration. Based on the input power and the heating capacity, a first energy efficiency ratio is determined for the heat pump unit in non-defrosting operation mode, and based on the total heating capacity and the total power consumption, a second energy efficiency ratio is determined for the heat pump unit in defrosting operation mode. The first energy efficiency ratio and the second energy efficiency ratio are compared, and the operating mode of the heat pump unit is determined based on the comparison result.

[0006] Optionally, the air inlet parameters include air inlet temperature and air inlet humidity, the air outlet parameters include air outlet temperature and air outlet humidity, and the operating parameters include fan speed, compressor power, fan power, and heating interval duration; The determination of the input power, heat output per unit time during the heating interval, and total heat output and total power consumption of the heat pump unit based on the inlet air parameters, the outlet air parameters, and the operating parameters includes: Based on the inlet air temperature, the inlet air humidity, and the preset enthalpy-humidity meter, the inlet air moisture content and inlet air enthalpy value are determined, and based on the outlet air temperature, the outlet air humidity, and the preset enthalpy-humidity meter, the outlet air moisture content and outlet air enthalpy value are determined. The preset enthalpy-humidity meter is used to characterize the mapping relationship between temperature, humidity, moisture content, and enthalpy value. Based on the fan speed, the fan air volume is determined, and based on the compressor power and the fan power, the input power is determined. Based on the fan air volume, the inlet air moisture content, the outlet air moisture content, the heating interval duration, and the preset air density, the frost mass is determined, and based on the frost mass, the preset ice melting heat, and the specific heat of water, the defrosting heat absorption is determined. The heating capacity is determined based on the fan air volume, the inlet enthalpy, the outlet enthalpy, the input power, and the air density. The total heat output is determined based on the defrosting heat absorption, the heat output, and the duration of the heating interval. The total power consumption is determined based on the input power, the heating interval duration, and the defrosting interval duration.

[0007] Optionally, the formula for calculating the total heat output is as follows: ; ; ; ; in, This represents the total heat output. This indicates the heat output. This indicates that the defrosting process absorbs heat. This represents the preset ambient temperature correction factor. This indicates the duration of the heating interval. This indicates the quality of the frost. This indicates the air volume of the fan. This indicates the air density. This indicates the moisture content of the outlet air. This indicates the moisture content of the incoming air. This indicates the heat of melting of the ice. This indicates the specific heat of the water. This indicates the outlet enthalpy value. This indicates the intake enthalpy value. This represents the input power.

[0008] Optionally, the formula for calculating the total power consumption is as follows: ; in, This indicates the total power consumption. This represents the input power during the duration of the heating interval. This indicates the duration of the heating interval. This represents the input power during the defrosting interval. This indicates the duration of the defrosting interval.

[0009] Optionally, determining the first energy efficiency ratio of the heat pump unit in non-defrost operation mode based on the input power and the heating capacity, and determining the second energy efficiency ratio of the heat pump unit in defrost operation mode based on the total heating capacity and the total power consumption, includes: Calculate a first ratio between the heating capacity and the input power, and determine the first ratio as the first energy efficiency ratio; Calculate a second ratio between the total heat output and the total power consumption, and determine the second ratio as the second energy efficiency ratio.

[0010] Optionally, comparing the first energy efficiency ratio and the second energy efficiency ratio, and determining the operating mode of the heat pump unit based on the comparison result, includes: Compare the first energy efficiency ratio and the second energy efficiency ratio; If the first energy efficiency ratio is greater than the second energy efficiency ratio, the heat pump unit is determined to operate in a defrost-free mode. If the first energy efficiency ratio is less than the second energy efficiency ratio, the heat pump unit is determined to operate in defrost mode. When the first energy efficiency ratio is equal to the second energy efficiency ratio, the operating mode of the heat pump unit is determined to be either a non-defrosting operating mode or a defrosting operating mode.

[0011] Optionally, the method further includes: Based on the aforementioned air intake parameters, the air intake dew point temperature is determined. If the inlet dew point temperature is lower than a preset threshold and the duration is longer than a preset duration, check whether frost forms on the fin surface. If frost is detected on the fin surface, the operation mode of the heat pump unit is switched to defrosting mode; If no frost is detected on the fin surface, the operation mode of the heat pump unit is switched to the defrost-free operation mode.

[0012] Optionally, detecting whether frost has formed on the surface of the fins includes: The drain solenoid valve of the heat pump unit is controlled to close, and the liquid level is detected by the liquid level sensor of the heat pump unit, which is located in the water receiving tray below the fins. When the liquid level is greater than zero, it is determined that frost has formed on the surface of the fins; If the liquid level is less than or equal to zero, it is determined that the fin surface is not frosted.

[0013] Secondly, this application embodiment also provides a heat pump unit, the heat pump unit including an inlet air temperature and humidity sensor disposed at the air inlet, an outlet air temperature and humidity sensor disposed at the air outlet, a liquid level sensor disposed in a water receiving tray below the fins, a fan, a compressor and a control unit. The air inlet temperature and humidity sensor is used to collect air inlet parameters, the air outlet temperature and humidity sensor is used to collect air outlet parameters, and the liquid level sensor is used to collect the liquid level of the condensate generated during defrosting. The inlet air temperature and humidity sensor, the outlet air temperature and humidity sensor, the liquid level sensor, the fan, and the compressor are all electrically connected to the control unit. The control unit is used to execute the control method of the heat pump unit described in the first aspect.

[0014] Thirdly, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the control method of the heat pump unit described in the first aspect.

[0015] Compared with the prior art, the above-mentioned technical solution provided in this application has the following advantages: The method provided in this application obtains the air inlet parameters, air outlet parameters, and operating parameters of the heat pump unit; based on the air inlet parameters, air outlet parameters, and operating parameters, it determines the input power of the heat pump unit, the heat output per unit time during the heating interval, and the total heat output and total power consumption during the entire defrosting cycle, wherein the entire defrosting cycle includes the heating interval duration and the defrosting interval duration; based on the input power and the heat output, it determines the first energy efficiency ratio of the heat pump unit in the non-defrosting operation mode, and based on the total heat output and the total power consumption, it determines the second energy efficiency ratio of the heat pump unit in the defrosting operation mode; it compares the first energy efficiency ratio and the second energy efficiency ratio, and determines the operating mode of the heat pump unit based on the comparison result. Using the above method, the first energy efficiency ratio (EER) of the heat pump unit in non-defrosting operation mode and the second EER in defrosting operation mode can be accurately determined based on the inlet air parameters, outlet air parameters, and operating parameters of the heat pump unit. Then, based on the first and second EERs, the operating mode with the higher EER can be intelligently selected for operation, thereby improving the overall energy efficiency of the heat pump unit. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 A schematic flowchart illustrating a control method for a heat pump unit provided in an embodiment of this application; Figure 2 A schematic diagram of the defrosting cycle capability curve provided in an embodiment of this application; Figure 3 A schematic flowchart illustrating another control method for a heat pump unit provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a heat pump unit provided in an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0022] To address the problem of low energy efficiency caused by the inability of existing heat pump units to intelligently select the most energy-efficient operating mode, this application provides a control method for a heat pump unit, a heat pump unit, and a storage medium, which can effectively improve the overall energy efficiency of the heat pump unit.

[0023] See Figure 1 , Figure 1 This is a schematic flowchart illustrating a control method for a heat pump unit provided in an embodiment of this application. Figure 1 As shown, the control method for this heat pump unit may include the following steps: Step S101: Obtain the air inlet parameters, air outlet parameters, and operating parameters of the heat pump unit.

[0024] Specifically, the aforementioned air intake parameters may include, but are not limited to, parameters such as air intake temperature and air intake humidity. The aforementioned air outlet parameters may include, but are not limited to, parameters such as air outlet temperature and air outlet humidity. The aforementioned operating parameters may include, but are not limited to, parameters such as fan speed, compressor power, fan power, and the duration of the heating zone during the defrosting cycle.

[0025] The aforementioned air intake parameters can be obtained by an air intake temperature and humidity sensor installed at the air intake. The aforementioned air outlet parameters can be obtained by an air outlet temperature and humidity sensor installed at the air outlet. The aforementioned operating parameters can be obtained in real time during the operation of the heat pump unit (such as fan speed, compressor power, fan power, etc.) and can also be preset (such as heating interval duration, etc.).

[0026] Step S102: Based on the air inlet parameters, air outlet parameters, and operating parameters, determine the input power of the heat pump unit, the heat output per unit time during the heating interval, and the total heat output and total power consumption during the entire defrosting cycle. The entire defrosting cycle includes the heating interval duration and the defrosting interval duration.

[0027] Specifically, the power consumption of the compressor (i.e., compressor power) and the power consumption of the fan motor (i.e., fan power) can be detected using the drive board, and the power consumption of the compressor and the fan motor can be determined as the input power of the aforementioned heat pump unit. The aforementioned heating capacity refers to the heat output generated by the heat pump unit per unit time during the heating interval. The aforementioned total heating capacity refers to the total heat output generated by the heat pump unit throughout the entire defrost cycle (heating interval duration plus defrost interval duration). The aforementioned total power consumption refers to the total power consumed by the heat pump unit throughout the entire defrost cycle (heating interval duration plus defrost interval duration).

[0028] When determining the input power of the heat pump unit, the heat output per unit time during the heating interval, and the total heat output and total power consumption during the entire defrosting cycle, the results can be calculated directly based on the air intake parameters, air outlet parameters, and operating parameters. Alternatively, the air intake parameters, air outlet parameters, and operating parameters can be input into a pre-trained neural network model for prediction. This application does not impose any specific limitations on these parameters.

[0029] Step S103: Determine the first energy efficiency ratio of the heat pump unit in the non-defrosting operation mode based on the input power and heating capacity, and determine the second energy efficiency ratio of the heat pump unit in the defrosting operation mode based on the total heating capacity and total power consumption.

[0030] Specifically, the first energy efficiency ratio (EER) of the heat pump unit in defrost-free operation mode can be determined based on the input power and heating capacity. For example, the ratio between input power and heating capacity can be calculated, and then this ratio can be determined as the first EER. Alternatively, the ratio between input power and heating capacity can be calculated, and then multiplied by a preset correction factor (such as 0.9 or 1.1) to obtain the first EER.

[0031] Furthermore, the second energy efficiency ratio (EER) of the heat pump unit in defrost mode can be determined based on the total heating capacity and total power consumption. For example, the ratio between total heating capacity and total power consumption can be calculated, and then this ratio can be determined as the second EER. Alternatively, the ratio between total heating capacity and total power consumption can be calculated, and then this ratio can be multiplied by a preset correction factor (such as 0.9 or 1.1) to obtain the second EER.

[0032] Step S104: Compare the first energy efficiency ratio and the second energy efficiency ratio, and determine the operating mode of the heat pump unit based on the comparison results.

[0033] Specifically, the first energy efficiency ratio and the second energy efficiency ratio can be compared, and then the operating mode with the higher energy efficiency ratio can be selected as the operating mode of the heat pump unit. For example, if the first energy efficiency ratio is higher than the second energy efficiency ratio, the non-defrosting operating mode can be used; if the first energy efficiency ratio is lower than the second energy efficiency ratio, the defrosting operating mode can be used.

[0034] Using the above method, the first energy efficiency ratio (EER) of the heat pump unit in non-defrosting operation mode and the second EER in defrosting operation mode can be accurately determined based on the inlet air parameters, outlet air parameters, and operating parameters of the heat pump unit. Then, based on the first and second EERs, the operating mode with the higher EER can be intelligently selected for operation, thereby improving the overall energy efficiency of the heat pump unit.

[0035] In one optional embodiment, the air inlet parameters include air inlet temperature and air inlet humidity, the air outlet parameters include air outlet temperature and air outlet humidity, and the operating parameters include fan speed, compressor power, fan power, and heating interval duration. Step S102 above, based on the inlet air parameters, outlet air parameters, and operating parameters, determines the input power of the heat pump unit, the heat output per unit time during the heating interval, and the total heat output and total power consumption throughout the entire defrosting cycle, including: Based on the inlet air temperature, inlet air humidity, and a preset enthalpy-humidity meter, the inlet air moisture content and inlet air enthalpy are determined. Similarly, based on the outlet air temperature, outlet air humidity, and a preset enthalpy-humidity meter, the outlet air moisture content and outlet air enthalpy are determined. The preset enthalpy-humidity meter is used to characterize the mapping relationship between temperature, humidity, moisture content, and enthalpy. Based on the fan speed, the fan air volume is determined, and based on the compressor power and fan power, the input power is determined. Based on the fan air volume, inlet air moisture content, outlet air moisture content, heating interval duration, and preset air density, the frost mass is determined, and based on the frost mass, preset ice melting heat, and water specific heat, the defrosting heat absorption is determined. The heating capacity is determined based on the fan air volume, inlet enthalpy, outlet enthalpy, input power, and air density. The total heating capacity is determined based on the defrosting heat absorption, heating capacity, and heating interval duration. The total power consumption is determined based on the input power, heating interval duration, and defrosting interval duration.

[0036] Specifically, based on inlet air parameters, outlet air parameters, and operating parameters, the input power of the heat pump unit, the heating capacity per unit time during the heating interval, and the total heating capacity and total power consumption throughout the entire defrosting cycle can be calculated. More specifically, based on inlet air temperature, inlet air humidity, and a preset enthalpy-humidity meter, information such as inlet air moisture content and inlet air enthalpy can be determined. Similarly, based on outlet air temperature, outlet air humidity, and the preset enthalpy-humidity meter, information such as outlet air moisture content and outlet enthalpy can be determined. The preset enthalpy-humidity meter is a table characterizing the mapping relationship between parameters such as temperature, humidity, moisture content, and enthalpy. It can be built into the heat pump unit's program, allowing the air state and parameters such as moisture content, enthalpy, and dew point temperature to be determined using temperature and humidity. Furthermore, based on the fan similarity law—that airflow is proportional to fan speed—the fan airflow of the heat pump unit can be determined, and the input power can be determined based on the compressor power and fan power.

[0037] Next, based on the fan airflow, inlet air humidity, outlet air humidity, heating interval duration, and preset air density, the mass of frost generated on the fins can be determined. Then, based on the frost mass, preset heat of melting, and specific heat of water, the heat absorption required to melt the frost corresponding to that mass can be determined. Furthermore, based on the fan airflow, inlet air enthalpy, outlet air enthalpy, input power, and air density, the heat output per unit time within the heating interval duration can be determined.

[0038] Then, the total heating capacity can be determined based on the defrosting heat absorption, heating capacity, and heating interval duration, and the total power consumption can be determined based on the input power, heating interval duration, and defrosting interval duration.

[0039] Using the above method, the input power of the heat pump unit, the heat output per unit time during the heating interval, and the total heat output and total power consumption during the entire defrosting cycle can be accurately calculated based on the inlet air parameters, outlet air parameters, and operating parameters. This facilitates the subsequent calculation of the energy efficiency ratio of the non-defrosting operation mode and the defrosting operation mode based on the input power of the heat pump unit, the heat output per unit time during the heating interval, and the total heat output and total power consumption during the entire defrosting cycle.

[0040] In one optional embodiment, the formula for calculating the total heat output is as follows: ; ; ; ; in, Indicates the total heat output. Indicates the heating capacity. This indicates that defrosting absorbs heat. This represents the preset ambient temperature correction factor. Indicates the duration of the heating interval. Indicates the quality of frost. This indicates the fan's air volume. Indicates air density, Indicates the moisture content of the air outlet. This indicates the moisture content of the incoming air. Indicates the heat of ice melting. Indicates the specific heat of water. Indicates the enthalpy value of the air outlet. Indicates the enthalpy value of the incoming air. This indicates the input power.

[0041] Specifically, the formula for calculating the mass of frost is as follows: ; in, Indicates the quality of frost. This indicates the fan's air volume. Indicates air density, Indicates the moisture content of the air outlet. This indicates the moisture content of the incoming air. This indicates the duration of the heating cycle. The air density here... A value of 1.2 kg / m³ can be used. Heating interval duration. This refers to the heating operation time during one defrost cycle, and its value can be obtained by correction based on actual measurements. As an optional implementation method, the heating interval duration... It can provide heating for 50 minutes (i.e., the heating duration within the ambient temperature range of +1℃ to +5℃, where frosting is likely to occur). (50 minutes).

[0042] The mass of frost calculated based on the above formula The heat absorbed during defrosting can be calculated using the following formula. : ; in, This indicates that defrosting absorbs heat. Indicates the quality of frost. Indicates the heat of ice melting. This represents the specific heat of water. Specifically, it represents the heat absorbed during defrosting. This refers to the heat absorbed by the fins when all the frost on them melts into water at 5°C (the average temperature of water after frost melts is typically 5°C). This refers to the heat of ice melting. The specific heat of water, C, is a constant, with a value of 334 kJ / kg. The specific heat of water, C, is also a constant, with a value of 4.187 kJ / (kg·℃). The mass of frost, m, is a key parameter, which can be obtained using the formula described above. The calculated value can be corrected by actual measurement as follows: During defrosting, after the condensate is collected in the drip tray at the bottom of the fins, the drain solenoid valve remains closed, allowing the condensate to accumulate in the drip tray. The liquid level height h is detected by a liquid level sensor installed in the drip tray. The area A of the drip tray is fixed and known, thus the condensate volume V = h × A can be obtained. Since the density of water is known to be 1 kg / L, the accurate mass m of the melted ice can be obtained to correct the above theoretical calculation value. It should be noted that an electric heating element can be installed at the bottom of the drip tray to prevent the water in the drip tray from freezing at low temperatures. After defrosting is complete, the drain solenoid valve is opened to drain the water.

[0043] The formula for calculating the above-mentioned heat output is as follows: ; in, Indicates the heating capacity. This indicates the fan's air volume. Indicates air density, Indicates the enthalpy value of the air outlet. Indicates the enthalpy value of the incoming air. This represents the input power. Here, the air density is... It can be 1.2 kg / m³. Input power. It is mainly used for the operation of two power components: compressor and fan, with input power. The power consumption of the compressor and fan can be detected by the driver board; the sum of the two is the input power. .

[0044] The defrosting heat absorption calculated based on the above formula and heat output The total calorific value can be calculated using the following formula. The calculation formula is as follows: ; in, Indicates the total heat output. Indicates the heating capacity. This indicates that defrosting absorbs heat. This represents the preset ambient temperature correction factor. This indicates the duration of the heating interval. The ambient temperature correction factor is located here. This can be corrected based on actual measurements; generally, 0.9 is used for the temperature range of +1℃ to +5℃. Heating duration. This is the heating operation time under one defrosting cycle, which can be corrected based on actual measurements. Generally, it is 50 minutes in the temperature range of +1℃ to +5℃.

[0045] Using the above method, the total heat generated throughout the entire defrosting cycle can be accurately obtained. This facilitates subsequent calculations based on the total heating capacity. Perform energy efficiency ratio calculation.

[0046] In an optional embodiment, the formula for calculating the total power consumption is as follows: ; in, Indicates total power consumption. This indicates the input power during the heating interval. Indicates the duration of the heating interval. This represents the input power during the defrosting interval. This indicates the defrosting interval duration. The input power within this heating interval duration is... This mainly refers to the sum of the power of the compressor and fan during the heating cycle, which can be detected by the drive board. The input power during the defrosting cycle... It mainly represents the sum of the power of the compressor and fan during the defrosting interval, which can be detected by the drive board.

[0047] It should be noted that a defrost cycle includes a heating period and a defrost period, the duration of which can be adjusted based on actual measurements. A defrost cycle can be calculated as follows: Figure 2 As shown.

[0048] Using the above method, the total power consumption of the entire defrosting cycle can be accurately obtained. This facilitates subsequent calculations based on the total power consumption. Perform energy efficiency ratio calculation.

[0049] In an optional embodiment, step S103, determining the first energy efficiency ratio of the heat pump unit in non-defrosting operation mode based on the input power and heating capacity, and determining the second energy efficiency ratio of the heat pump unit in defrosting operation mode based on the total heating capacity and total power consumption, includes: Calculate the first ratio between heating capacity and input power, and determine the first ratio as the first energy efficiency ratio; Calculate a second ratio between total heating capacity and total power consumption, and determine the second ratio as the second energy efficiency ratio.

[0050] Specifically, when the heat pump unit is in defrost-free operation mode, the heating capacity and power consumption of the heat pump unit are stable. When determining the first energy efficiency ratio, the first ratio between the heating capacity and the input power can be directly calculated, and then this first ratio can be used as the first energy efficiency ratio.

[0051] When the heat pump unit is in defrost mode, it periodically performs heating and defrosting, and its capacity curve is as follows: Figure 2As shown, the second energy efficiency ratio of the heat pump unit in defrost mode is determined, which is the energy efficiency ratio of the heat pump unit for one defrost cycle (i.e., the average energy efficiency ratio of the heat pump unit). This second energy efficiency ratio is equal to the second ratio between total heating capacity and total power consumption.

[0052] Using the above method, the first energy efficiency ratio of the heat pump unit in non-defrosting operation mode and the second energy efficiency ratio of the heat pump unit in defrosting operation mode can be accurately determined, and then the final operation mode of the heat pump unit can be determined based on the first energy efficiency ratio and the second energy efficiency ratio.

[0053] In an optional embodiment, step S104, comparing the first energy efficiency ratio and the second energy efficiency ratio, and determining the operating mode of the heat pump unit based on the comparison result, includes: Compare the first energy efficiency ratio and the second energy efficiency ratio; When the first energy efficiency ratio is greater than the second energy efficiency ratio, the heat pump unit is determined to operate in a defrost-free mode. When the first energy efficiency ratio is less than the second energy efficiency ratio, the heat pump unit is determined to operate in defrosting mode. When the first energy efficiency ratio is equal to the second energy efficiency ratio, the operating mode of the heat pump unit is determined to be either non-defrosting operation mode or defrosting operation mode.

[0054] Specifically, when determining the final operating mode of the heat pump unit based on the first energy efficiency ratio and the second energy efficiency ratio, the first energy efficiency ratio and the second energy efficiency ratio can be compared. If the first energy efficiency ratio is greater than the second energy efficiency ratio, the operating mode of the heat pump unit can be determined to be the non-defrosting operating mode; if the first energy efficiency ratio is less than the second energy efficiency ratio, the operating mode of the heat pump unit can be determined to be the defrosting operating mode; if the first energy efficiency ratio is equal to the second energy efficiency ratio, the operating mode of the heat pump unit can be determined to be either the non-defrosting operating mode or the defrosting operating mode.

[0055] By using the above method, the operating mode with the higher energy efficiency ratio can be intelligently selected based on the first energy efficiency ratio and the second energy efficiency ratio as the final operating mode of the heat pump unit, thereby improving the overall energy efficiency of the heat pump unit.

[0056] In an optional embodiment, the method further includes: Based on the air intake parameters, the air intake dew point temperature is determined. If the inlet dew point temperature is lower than the preset threshold and the duration is longer than the preset duration, check whether frost forms on the fin surface. If frost is detected on the fin surface, switch the heat pump unit to defrost mode. If no frost is detected on the fin surface, switch the heat pump unit to defrost-free operation mode.

[0057] Specifically, the inlet dew point temperature can be determined based on the inlet air parameters. When the detected inlet dew point temperature is lower than the preset threshold and the duration is longer than the preset duration, it is possible to detect whether frost forms on the fin surface. If frost is detected on the fin surface, the operation mode of the heat pump unit can be switched to defrosting operation mode; if no frost is detected on the fin surface, the operation mode of the heat pump unit can be switched to non-defrosting operation mode.

[0058] Thus, when the heat pump unit is in a low temperature and low humidity range (such as ambient temperature below -10℃), the dew point temperature of the air is usually low, and the fin surface is not easy to frost. However, the heat pump unit usually detects that the evaporation temperature is too low and enters defrosting (in fact, the fins are not frostbed), resulting in ineffective heat loss.

[0059] In an optional embodiment, the above step of detecting whether frost has formed on the fin surface includes: The drain solenoid valve of the heat pump unit is closed, and the liquid level is detected by the liquid level sensor of the heat pump unit, which is located in the water receiving tray below the fins. When the liquid level is greater than zero, frost is confirmed on the fin surface; If the liquid level is less than or equal to zero, confirm that there is no frost on the fin surface.

[0060] Specifically, when detecting whether frost has formed on the fin surface, the drain solenoid valve of the heat pump unit can be closed, and the liquid level sensor of the heat pump unit can be used to detect the liquid level. If the liquid level is greater than zero, it can be determined that frost has formed on the fin surface; if the liquid level is less than or equal to zero, it can be determined that no frost has formed on the fin surface. In this way, it is possible to accurately determine whether frost has formed on the fin surface, and then adjust the operation mode of the heat pump unit accordingly.

[0061] In an optional embodiment, the control method for the heat pump unit provided in this application can intelligently predict the energy efficiency of defrosting and non-defrosting operation in the ambient temperature range where frost is likely to form, and intelligently select the more energy-efficient operating mode. The process is as follows: Figure 3 As shown. Furthermore, the control method for the heat pump unit provided in this application embodiment can intelligently determine whether the fins are truly frosted when the heat pump unit is operating in a low-temperature, low-humidity ambient temperature range, preventing the fins from entering defrosting mode without frost, avoiding ineffective heat consumption, thereby improving the unit's heating capacity and overall operating energy efficiency. The implementation process is as follows: (1) When the inlet dew point temperature does not change significantly and the fan speed and compressor frequency do not change: In the first defrosting cycle, the drain solenoid valve is kept closed. After defrosting, the liquid level height h is detected by the liquid level sensor. When h=0 is detected, it is considered that there is no condensate in this defrosting cycle and no frost in this cycle. Even if the defrosting entry condition is detected in subsequent cycles, defrosting will not be performed.

[0062] (2) When the inlet dew point temperature is detected to be high, or the fan speed is reduced, or the compressor frequency is increased, the heat pump unit may enter defrosting and needs to be re-detected for a cycle. If h=0 is still detected, it is considered that there is no condensate in this defrosting cycle and no defrosting will be performed in subsequent cycles. If h>0 is detected, it means that frost has formed and the defrosting cycle needs to be entered periodically.

[0063] (3) Under other circumstances, it will not enter defrosting mode and will continue to operate without defrosting.

[0064] In this way, sensors can intelligently predict the energy efficiency of defrosting and non-defrosting operation. In ambient temperature ranges where frost is likely to form, the system can select the more energy-efficient operating mode, thereby saving power consumption of the heat pump unit and making it more energy-saving. Furthermore, when the heat pump unit is operating in a low-temperature and low-humidity ambient temperature range, the system can intelligently determine whether the fins are truly frosted, preventing the fins from entering the defrosting process without frost, thus avoiding ineffective heat loss and improving the heating capacity of the heat pump unit, thereby improving the overall operating energy efficiency.

[0065] See Figure 4 , Figure 4 This is a schematic diagram of a heat pump unit provided in an embodiment of this application. Figure 4 As shown, the heat pump unit includes an inlet air temperature and humidity sensor 401 installed at the air inlet, an outlet air temperature and humidity sensor 402 installed at the air outlet, a liquid level sensor 403 installed in the water receiving tray below the fins, a fan 404, a compressor (not shown in the figure), and a control unit (not shown in the figure). Among them, the air inlet temperature and humidity sensor 401 is used to collect air inlet parameters, the air outlet temperature and humidity sensor 402 is used to collect air outlet parameters, and the liquid level sensor 403 is used to collect the liquid level of the condensate generated during defrosting. The inlet air temperature and humidity sensor 401, the outlet air temperature and humidity sensor 402, the liquid level sensor 403, the fan 404, and the compressor are all electrically connected to the control unit; The control unit is used to execute the control method of the heat pump unit in the foregoing method embodiments, and can achieve the same function as the control method of the heat pump unit in the foregoing method embodiments, which will not be described again here.

[0066] It should be noted that the heat pump unit also includes a drain solenoid valve 405 and a chassis electric heating belt 406. The drain solenoid valve 405 is used to control the drainage of water in the water tray. The chassis electric heating belt 406 is located at the bottom of the water tray to ensure that the water in the water tray does not freeze at low temperatures. After defrosting, the drain solenoid valve is opened to drain the water.

[0067] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the control method for a heat pump unit as provided in any of the foregoing method embodiments.

[0068] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0069] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0070] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0071] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A control method of a heat pump unit, characterized by, The method comprises: obtaining an inlet air parameter, an outlet air parameter and an operation parameter of a heat pump unit; determining, based on the inlet air parameter, the outlet air parameter and the operation parameter, an input power of the heat pump unit, a heating capacity per unit time in a heating interval duration, and a total heating capacity and a total power consumption in a whole defrosting cycle, the whole defrosting cycle comprising the heating interval duration and a defrosting interval duration; determining, according to the input power and the heating capacity, a first energy efficiency ratio of the heat pump unit in a non-defrosting operation mode, and determining, according to the total heating capacity and the total power consumption, a second energy efficiency ratio of the heat pump unit in a defrosting operation mode; comparing the first energy efficiency ratio and the second energy efficiency ratio, and determining an operation mode of the heat pump unit according to a comparison result.

2. The method of claim 1, wherein, The inlet air parameter comprises an inlet air temperature and an inlet air humidity, the outlet air parameter comprises an outlet air temperature and an outlet air humidity, and the operation parameter comprises a fan rotating speed, a compressor power, a fan power and the heating interval duration; The determining, based on the inlet air parameter, the outlet air parameter and the operation parameter, the input power of the heat pump unit, the heating capacity per unit time in the heating interval duration, and the total heating capacity and the total power consumption in the whole defrosting cycle, comprises: determining, based on the inlet air temperature, the inlet air humidity and a preset enthalpy-humidity table, an inlet air humidity content and an inlet air enthalpy value, and determining, based on the outlet air temperature, the outlet air humidity and the preset enthalpy-humidity table, an outlet air humidity content and an outlet air enthalpy value, the preset enthalpy-humidity table being used to represent a mapping relationship between temperature, humidity, humidity content and enthalpy value; determining, based on the fan rotating speed, a fan air volume, and determining, based on the compressor power and the fan power, the input power; determining, based on the fan air volume, the inlet air humidity content, the outlet air humidity content, the heating interval duration and a preset air density, an ice frost mass, and determining, based on the ice frost mass, a preset ice melting heat and a specific heat of water, a defrosting heat absorption amount; determining, based on the fan air volume, the inlet air enthalpy value, the outlet air enthalpy value, the input power and the air density, the heating capacity; determining, based on the defrosting heat absorption amount, the heating capacity and the heating interval duration, the total heating capacity; determining, based on the input power, the heating interval duration and the defrosting interval duration, the total power consumption.

3. The method of claim 2, wherein, A calculation formula of the total heating capacity is as follows: ； ； ； ； wherein, represents the total heating capacity, represents the heating capacity, represents the defrosting heat absorption amount, represents a preset ambient temperature correction coefficient, represents the heating interval duration, represents the ice and frost mass, represents the fan air volume, represents the air density, represents the outlet air moisture content, represents the inlet air moisture content, represents the ice melting heat, represents the specific heat of water, represents the outlet air enthalpy, represents the inlet air enthalpy, represents the input power.

4. The method of claim 2, wherein, A calculation formula of the total power consumption is as follows: ； wherein, represents the total power consumption, represents the input power in the heating interval duration, represents the heating interval duration, represents the input power in the defrosting interval duration, represents the defrosting interval duration.

5. The method of claim 1, wherein, The determining, according to the input power and the heating capacity, the first energy efficiency ratio of the heat pump unit in the non-defrosting operation mode, and the determining, according to the total heating capacity and the total power consumption, the second energy efficiency ratio of the heat pump unit in the defrosting operation mode, comprises: calculating a first ratio value between the heating capacity and the input power, and determining the first ratio value as the first energy efficiency ratio; calculating a second ratio value between the total heating capacity and the total power consumption, and determining the second ratio value as the second energy efficiency ratio.

6. The method of claim 1, wherein, The comparing the first energy efficiency ratio and the second energy efficiency ratio and determining the operation mode of the heat pump unit according to the comparison result comprises: comparing the first energy efficiency ratio and the second energy efficiency ratio; in the case that the first energy efficiency ratio is greater than the second energy efficiency ratio, determining the operation mode of the heat pump unit as the defrost-free operation mode; in the case that the first energy efficiency ratio is less than the second energy efficiency ratio, determining the operation mode of the heat pump unit as the defrost operation mode; in the case that the first energy efficiency ratio is equal to the second energy efficiency ratio, determining the operation mode of the heat pump unit as the defrost-free operation mode or the defrost operation mode.

7. The method of claim 1, wherein, The method further comprises: determining the inlet air dew point temperature based on the inlet air parameter; in the case that the inlet air dew point temperature is lower than the preset threshold value and the duration is greater than the preset duration, detecting whether the fin surface is frosted; in the case that the fin surface is detected to be frosted, switching the operation mode of the heat pump unit to the defrost operation mode; in the case that the fin surface is detected to be not frosted, switching the operation mode of the heat pump unit to the defrost-free operation mode.

8. The method of claim 7, wherein, The detecting whether the fin surface is frosted comprises: controlling the drain electromagnetic valve of the heat pump unit to be closed and detecting the liquid level height by the liquid level height sensor of the heat pump unit, the liquid level height sensor being arranged in the water pan below the fin; in the case that the liquid level height is greater than zero, determining that the fin surface is frosted; in the case that the liquid level height is less than or equal to zero, determining that the fin surface is not frosted.

9. A heat pump unit, characterized by The heat pump unit comprises an inlet air temperature and humidity sensor arranged at the air inlet, an outlet air temperature and humidity sensor arranged at the air outlet, a liquid level height sensor arranged in the water pan below the fin, a fan, a compressor and a control unit; wherein the inlet air temperature and humidity sensor is used to collect the inlet air parameter, the outlet air temperature and humidity sensor is used to collect the outlet air parameter, and the liquid level height sensor is used to collect the liquid level height of the condensed water generated during defrosting; the inlet air temperature and humidity sensor, the outlet air temperature and humidity sensor, the liquid level height sensor, the fan and the compressor are all electrically connected with the control unit; the control unit is used to execute the control method of the heat pump unit according to any one of claims 1-8.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the control method of the heat pump unit according to any one of claims 1-8.

Images