A heat pump unit with a backup heat source

Abstract

The present application relates to a kind of heat pump unit with backup heat source, including the method for controlling the start-stop of heat pump and backup heat source, the start-stop of compressor and backup heat source is determined by ambient temperature and preset heat pump ring temperature starting threshold value, backup heat source ring temperature starting threshold value, the waiting time of starting backup heat source is determined by the temperature difference of preset target temperature and monitoring temperature and preset heating capacity integral value, the waiting time of starting backup heat source is more finely controlled by the temperature fluctuation of preset target temperature and monitoring temperature, using cumulative integral method.The control method can guarantee the heating, heating demand of user in low temperature and super low temperature environment, improve the heating experience of user, reduce the cost of heating, improve energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of heat pumps, and more particularly to a heat pump unit with a backup heat source. Background Technology

[0002] Heat pump units are highly efficient and energy-saving devices that can transfer heat from a low-temperature heat source to a high-temperature heat source for utilization. As a result, more and more residential applications are choosing heat pump units to meet the cooling and heating needs of home and work environments.

[0003] When the outdoor ambient temperature drops to -7℃, the heating capacity of the heat pump decreases rapidly. When the outdoor ambient temperature drops to -15℃, frost forms on the surface of the heat exchanger on the outside of the heat pump, increasing the heat transfer resistance. This means the heat transfer resistance of the air-side heat exchanger increases, the evaporation temperature decreases, leading to a decline in the unit's performance, a deterioration in operating conditions, and a significant drop in heating capacity. Low and ultra-low temperature environments will severely affect the performance of the heat pump unit and compressor, increasing energy consumption and reducing energy efficiency. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a heat pump unit with a backup heat source, which enables the heat pump unit to start different heating devices according to different ambient temperatures through a set heating equipment control program when the ambient temperature is extremely low, so as to minimize the energy consumption of the entire multi-heat source heat pump unit while ensuring the user's heat demand, thereby improving the energy efficiency of the entire multi-heat source heat pump unit.

[0005] A heat pump unit with a backup heat source includes a compressor, a four-way valve, a water-side heat exchanger, a throttling valve, and an air-side heat exchanger connected sequentially via a refrigerant circulation pipeline; a backup heat source located at the outlet of the water-side heat exchanger; several temperature sensors; and a controller electrically and / or communicatively connected to the compressor, the backup heat source, and the temperature sensors. The controller controls the start and stop of the compressor and the backup heat source using the following method:

[0006] When a user has a heat demand, the current ambient temperature is obtained and compared with a preset heat pump ambient temperature start-up threshold.

[0007] If the current ambient temperature is greater than or equal to the heat pump ambient temperature start-up threshold, the compressor will start and the backup heat source will not be started.

[0008] If the current ambient temperature is lower than the heat pump ambient temperature start-up threshold, then the current ambient temperature is further compared with the preset backup heat source ambient temperature start-up threshold:

[0009] If the current ambient temperature is lower than the start-up threshold of the backup heat source, the backup heat source will be started, and the compressor will not be started.

[0010] If the current ambient temperature is greater than or equal to the backup heat source ambient temperature start-up threshold, the compressor is started, and the monitored temperature is further obtained. Based on the preset heating capacity integral value, the preset target temperature and the temperature difference between the monitored temperature, the waiting time t for starting the backup heat source is obtained, and the backup heat source is started after the waiting time t.

[0011] Compared with existing technologies, the heat pump unit of the present invention determines the start and stop of the compressor and the backup heat source by using the ambient temperature and the preset heat pump ambient temperature start threshold and the backup heat source ambient temperature start threshold. It determines the waiting time for starting the backup heat source by using the temperature difference between the preset target temperature and the monitored temperature and the preset integral value of the heating capacity. This control method can ensure the heating and heat use needs of users in low temperature and ultra-low temperature environments, improve the user's heating experience, reduce heating and heat use costs, and improve energy efficiency.

[0012] Furthermore, the waiting time t satisfies the following relationship:

[0013] t = I PV / ΔT=I PV / (T target -T M )

[0014] Among them, I PV T represents the preset integral value of heating capacity. target T represents the preset target temperature. M The value represents the monitored temperature, and ΔT represents the temperature difference between the preset target temperature and the monitored temperature.

[0015] When the heat pump unit adopts the water temperature control mode, the target temperature is the target water temperature at the outlet of the heat exchanger on the water source side, and the monitored temperature is the actual water temperature at the outlet of the heat exchanger on the water source side; when the heat pump unit adopts the indoor temperature control mode, the target temperature is the target indoor room temperature, and the monitored temperature is the actual indoor room temperature.

[0016] Furthermore, it also includes continuously acquiring the monitored temperature during the waiting time t, and comparing the temperature fluctuation of the (i+1)th acquired temperature with that of the ith acquired temperature with a preset temperature fluctuation threshold:

[0017] If the temperature fluctuation is less than the temperature fluctuation threshold, the temperature fluctuation is ignored, and the backup heat source is turned on after the waiting time.

[0018] If the temperature fluctuation is greater than or equal to the temperature fluctuation threshold, then calculate each waiting time component t in segments. j The cumulative waiting time t corresponding to the integral value of heating capacity is obtained. total And during the cumulative waiting time t totalThen, the backup heat source is activated. By using a set integral control method based on the temperature fluctuation of the preset target temperature and the monitored temperature, the waiting time for activating the backup heat source can be more precisely controlled, resulting in better cost reduction and efficiency improvement.

[0019] Furthermore, the segmented calculation of each waiting time component t j To be carried out in accordance with the following method:

[0020] For temperature differences prior to the (i+1)th data acquisition where the temperature fluctuation is less than the temperature fluctuation threshold, the temperature fluctuation is ignored, and the initial temperature difference is used to adjust the waiting time component t. pass Accumulate points by performing the point calculation;

[0021] The remaining integral is obtained based on the preset heating capacity integral value and the accumulated integral. The remaining waiting time component t is then obtained by using the remaining integral and the temperature difference corresponding to the monitoring temperature of the (i+1)th acquisition. remain .

[0022] Furthermore, the cumulative integral satisfies the following equation:

[0023]

[0024] Among them, I pass This represents the time from the start of the determined waiting period to the (i+1)th temperature monitoring acquisition, where the initial temperature difference when the temperature fluctuation is less than the temperature fluctuation threshold is expressed as a function of the waiting time t. pass The cumulative integral; ΔT represents the temperature difference corresponding to the first monitored temperature when the temperature fluctuation is less than the temperature fluctuation threshold; t pass This represents the waiting time elapsed from the start of the determined waiting period until the (i+1)th temperature monitoring data collection.

[0025] The remaining integral satisfies the following equation:

[0026] I remain =I PV -I pass

[0027] Among them, I remain I represents the remaining integral. PV This represents the preset integral value of the heating capacity.

[0028] Furthermore, the remaining waiting time component t remain Satisfy the following formula:

[0029] t remain =I remain / ΔT i+1 .

[0030] Among them, t remainΔT1 represents the remaining waiting time for the temperature difference from the (i+1)th temperature sample collected for the remaining integral. i+1 This represents the temperature difference of the monitored temperature during the (i+1)th acquisition;

[0031] The cumulative waiting time t total Satisfy the following formula:

[0032] t total =t pass +t remain .

[0033] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a heat pump unit according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram illustrating the integral of temperature difference and waiting time according to an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram illustrating the integration of temperature difference and segmented waiting time according to an embodiment of the present invention. Detailed Implementation

[0037] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings of the embodiments of the present invention.

[0038] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, unless otherwise stated, “a plurality” means two or more; and the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0039] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only for distinction and not to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0040] To address the issue of rapid capacity reduction in heat pump units under low and ultra-low temperature environments, which negatively impacts user heating experience, this invention proposes a heat pump unit with a backup heat source. The method includes a method for controlling the start-up and shutdown of the heat pump and backup heat source. This method determines the start-up and shutdown of the compressor and backup heat source based on the ambient temperature and preset start-up thresholds for the heat pump and backup heat source. It determines the waiting time for activating the backup heat source by using the temperature difference between a preset target temperature and a monitored temperature, as well as a preset integral value of the heating capacity. Furthermore, it uses a cumulative integral method based on temperature fluctuations between the preset target temperature and the monitored temperature to achieve more precise control over the waiting time for activating the backup heat source. This control method ensures users' heating needs are met under low and ultra-low temperature conditions, improves the user heating experience, reduces heating costs, and increases energy efficiency.

[0041] For specific implementation details, please refer to [link / reference]. Figure 1 The heat pump unit with a backup heat source proposed in this invention includes a compressor (not shown), a four-way valve (not shown), a water source heat exchanger 10, a throttling valve (not shown), an air-side heat exchanger (not shown), a backup heat source module 20, several temperature sensors (not shown), a controller (not shown), and other auxiliary pipes. The compressor, four-way valve, water source heat exchanger 10, throttling valve, and air-side heat exchanger are sequentially connected via refrigerant piping; the backup heat source module 20 is connected via water piping; the controller is electrically and / or communicatively connected to the compressor 10, the backup heat source module 20, and several temperature sensors. Specifically, the inlet and outlet of the water source heat exchanger 10, the backup heat source module 20, and the user end form a water circulation pipeline; the high-temperature, high-pressure gaseous refrigerant generated by the compressor flows through the water source heat exchanger 10, releasing heat to the water side of the water source heat exchanger 10 to heat the incoming water.

[0042] The backup heat source module 20 includes at least one backup heat source, which may be one or more sets of heating devices. When there is only one backup heat source, it is located at the outlet end of the water source heat exchanger 10. The backup heat source includes, but is not limited to, gas-fired wall-hung boilers, electric boilers, electric heating, etc.

[0043] One embodiment of this application provides three backup heat sources: a first backup heat source 21, a second backup heat source 22, and a third backup heat source 23, and a three-way valve 24. The first backup heat source 21 is located at the outlet of the water source-side heat exchanger 10 and is used to heat the water flowing out of the outlet of the water source-side heat exchanger 10. The second backup heat source 22 is located between the outlet of the water source-side heat exchanger 10 and the user's heating end, and is used to heat the hot water entering the user's underfloor heating pipe 30. The third backup heat source 23 is located between the outlet of the water source-side heat exchanger 10 and the user's water supply end, and is used to heat the hot water entering the user's hot water tank 40. The three-way valve 24 is located at the outlet of the water source-side heat exchanger 10, wherein the common valve port is connected to the outlet of the water source-side heat exchanger 10, the first switching valve port is connected to the user's underfloor heating pipe 30, and the second switching valve port is connected to the user's hot water tank 40. When heating is needed at the user's end, the electric three-way valve connects the outlet of the water source heat exchanger 10 to the user's underfloor heating pipe 30, meaning the heating end is open while the hot water end is closed. When hot water is needed at the user's end, the water end is open while the heating end is closed. During the heating process, if defrosting, heat pump failure, or antifreeze occurs, the outlet of the water source heat exchanger 10 needs to be connected to the user's hot water tank 40 for defrosting and antifreeze operations. At this time, the third backup heat source 23 located at the user's water end needs to be activated.

[0044] The plurality of temperature sensors includes a first temperature sensor (not shown), a second temperature sensor (not shown), and a third temperature sensor (not shown). The first temperature sensor is used to collect the ambient temperature signal and transmit it to the controller. Its location is not limited in this application, as long as it can transmit the ambient temperature signal to the controller. The second temperature sensor is located at the outlet end of the heat exchanger 10 on the water source side, and is used to collect the outlet water temperature and transmit it to the controller. The third temperature sensor is located in the room where the underfloor heating pipes 30 are installed, and is used to collect the indoor ambient temperature and transmit it to the controller.

[0045] The controller receives the temperature signal transmitted by the temperature sensor.

[0046] The controller also includes a storage unit and a processing unit. The storage unit is used to store preset heat pump ambient temperature start-up thresholds. Backup heat source ambient temperature start-up threshold Heat pump heating capacity threshold The ambient temperature collected by the temperature sensor at each time point The processing unit includes a program for controlling the start and stop of the compressor 10 and the backup heat source module 20. The processing unit is used to determine the ambient temperature. Whether the start-up conditions of compressor 10 and / or backup heat source module 20 are met; the processing unit is also used to calculate the heat pump heating capacity of the heat pump unit under the current ambient temperature. and the preset heating threshold The system compares and judges the results, and outputs start-stop control signals to the compressor 10 or the backup heat source module 20 to control the start-stop of the heat pump unit's compressor 10 or backup heat source module 20.

[0047] Specifically, please refer to Figure 2 The controller controls the start and stop of the compressor 10 or the standby heat source module 20 of the heat pump unit through the following steps.

[0048] S10 acquires users' calorie needs information in real time:

[0049] If there is a heat requirement, then execute S20;

[0050] If there is no heat demand, then stop operating the compressor and the backup heat source module.

[0051] S20 obtains the current ambient temperature. and the current ambient temperature With preset heat pump ambient temperature start-up threshold Comparison:

[0052] If the current ambient temperature Greater than or equal to the heat pump ambient temperature start-up threshold The compressor will start, but the backup heat source module will not.

[0053] If the current ambient temperature Less than the heat pump ambient temperature start-up threshold Then proceed to step S30.

[0054] The heat pump ambient temperature start-up threshold The preferred temperature is -1℃ to 1℃.

[0055] S30 further specifies the current ambient temperature. With the preset backup heat source ambient temperature start-up threshold Comparison:

[0056] If the current ambient temperature Greater than or equal to the ambient temperature start-up threshold of the backup heat source Then start the compressor and execute step S40;

[0057] If the current ambient temperature Less than the backup heat source ambient temperature start-up threshold Then the backup heat source module will be activated, but the compressor will not be activated.

[0058] The backup heat source ambient temperature start-up threshold The preferred temperature range is -14℃ to -16℃.

[0059] S40 acquires the monitored temperature T H According to the preset target temperature T target and heating assessment temperature difference threshold ΔT TV The heating capacity of the heat pump is assessed: if the heating capacity is sufficient, the compressor remains running and the backup heat source is not activated; if the heating capacity is insufficient, the preset integral value of the heating capacity I is used. PV Target temperature T target and monitoring temperature T H The temperature difference is used to determine the waiting time t for starting the backup heat source, and the backup heat source is started after the waiting time t.

[0060] This step includes the following sub-steps.

[0061] S41 acquires the monitored temperature T H Calculate the preset target temperature T target With the monitored temperature T H The temperature difference ΔT is calculated, and the temperature difference ΔT is compared with a preset heating evaluation temperature difference threshold ΔT. TV Comparison:

[0062] If the temperature difference ΔT is less than or equal to the heating assessment temperature difference threshold ΔT TV If the compressor is not activated, the backup heat source will remain running.

[0063] If the temperature difference ΔT is greater than the heating assessment temperature difference threshold ΔT TV Then proceed to step S42.

[0064] When a heat pump unit with a backup heat source adopts water temperature control mode, the monitored temperature T H The target temperature T is the actual water temperature at the outlet of the heat exchanger 10 on the water source side. target The target water temperature at the outlet of the heat exchanger 10 on the water source side. When the heat pump unit with a backup heat source adopts the indoor temperature control mode, the monitored temperature T... H The target temperature T is the actual indoor room temperature. target The target room temperature.

[0065] The temperature difference ΔT satisfies: ΔT = T target -T H .

[0066] Furthermore, the preset target temperature T can be... target First, make corrections, then calculate the corrected target temperature T′. target With the monitored temperature T HThe temperature difference ΔT′. The correction is made by subtracting a fixed correction amount, i.e., T′. target =T target -C; The value of the fixed correction amount C is related to the environment in which the heat pump unit is applied, and is preferably 1 to 3°C.

[0067] S42 calculates the heating capacity integral value I based on the preset value. PV Based on the temperature difference ΔT, determine the waiting time t for starting the backup heat source, and start the backup heat source after the waiting time t.

[0068] The waiting time t satisfies equation (1):

[0069] t = I PV / ΔT=I PV / (T target -T H (1)

[0070] Corresponding to the corrected target temperature T′ target The waiting time t satisfies equation (2):

[0071] t = I PV / ΔT′=I PV / (T′ target -T H ) = I PV / (T target -CT H (2)

[0072] Furthermore, in order to obtain a more accurate waiting time for starting the backup heat source and to achieve better energy-saving results, in other embodiments, step S42 can be replaced with S`42.

[0073] S`42 is based on the preset heating capacity integral value I PV Based on the temperature difference ΔT, the waiting time t for activating the backup heat source is calculated. During the waiting time t, the monitored temperature T is continuously acquired. H and the monitored temperature collected in the (i+1)th time The monitored temperature of the i-th acquisition Temperature fluctuations With respect to the preset temperature fluctuation threshold ΔT TV Comparison:

[0074] If temperature fluctuations Less than the temperature fluctuation threshold ΔT TV If the temperature fluctuation is ignored, the backup heat source will be turned on after a waiting time t.

[0075] If temperature fluctuations Greater than or equal to the temperature fluctuation threshold ΔT TVThen, calculate each waiting time component t in segments. j The cumulative waiting time t corresponding to the integral value of heating capacity is obtained. total And during the cumulative waiting time t total Then activate the backup heat source;

[0076] Where i∈(2,n), and n is the total number of temperature monitoring measurements taken within the waiting time t.

[0077] The temperature fluctuation threshold ΔT T-F The preferred temperature is 0.2℃ to 0.4℃, which can be set according to the actual operating environment of the heat pump unit.

[0078] Specifically, the cumulative waiting time t corresponding to the integral value of heating capacity. total It is obtained through the following method.

[0079] For the temperature difference ΔT before the (i+1)th data acquisition, where the temperature fluctuation is less than the temperature fluctuation threshold... i Ignore temperature fluctuations The temperature difference ΔT corresponding to the monitored temperature is first detected when the temperature fluctuation is less than the temperature fluctuation threshold. 1 For the waiting time component t pass Integrate to obtain the cumulative integral I. pass The I mentioned pass Satisfying equation (3):

[0080]

[0081] Based on the preset integral value of heating capacity I PV With the cumulative integral I pass Obtain the remaining integral I remain The remaining integral I remain Satisfying equation (4):

[0082] I remain =I PV -I pass (4)

[0083] Then, based on the remaining integral I remain The temperature difference ΔT corresponding to the monitoring temperature of the (i+1)th acquisition i+1 Obtain the remaining waiting time component t remain The remaining waiting time component t remain Satisfying equation (5):

[0084] t remain =I remain / ΔT i+1 (5)

[0085] Then, based on the waiting time component t... passand the remaining waiting time component t remain Get the cumulative waiting time t total The cumulative waiting time t total Satisfying equation (6):

[0086] t total =t pass +t remain (5)

[0087] Please see Figure 2 and Figure 3 The following examples illustrate this.

[0088] The heat pump unit adopts a water temperature control mode, and its preset heat pump ambient temperature start-up threshold is... Backup heat source ambient temperature start-up threshold Target water temperature With a fixed correction C = 2℃, the integral value of the heating capacity I PV =50℃*min, temperature fluctuation threshold ΔT TV =0.2℃.

[0089] When the heat pump unit has a heat demand, the ambient temperature obtained is... Between -15℃ and 0℃, the heat pump compressor is started to provide heating, and the actual water temperature T is obtained simultaneously. H =40℃, then the calculated standby heat source start-up waiting time t = 50℃*min / (45-2-40)℃ = 16.7min.

[0090] If the fluctuation range of the actual water temperature collected each time is less than 0.2℃, then the backup heat source will be activated after 16.7 minutes.

[0091] If the actual water temperature collected in the (i+1)th time after 5 minutes is The actual water temperature collected in the i-th sampling was... At this point, the temperature fluctuation is 0.2℃, which is equal to the temperature fluctuation threshold ΔT. TV =0.2℃, then the heating integral and waiting time components before and after the fluctuation need to be calculated separately:

[0092] Cumulative integral I of heating before fluctuation pass = (45-2-40)℃*5min = 15℃*min, where t is the waiting time component. pass =5min;

[0093] Residual integral I of heating after fluctuation remain =50℃*min - 15℃*min = 35℃*min, remaining waiting time component t remain =35℃*min / (45-2-40.2)℃=12.5min;

[0094] Cumulative waiting time t total =5min + 12.5min = 17.5min, so the backup heat source will be activated after 17.5min.

[0095] The greater the temperature difference between the actual water temperature and the target water temperature, the slower the temperature rises, and the sooner the backup heat source needs to be activated.

[0096] Furthermore, when there are multiple sets of the first backup heat source 21, the second backup heat source 22, or the third backup heat source 23, they need to be activated one by one. When the first set of backup heat sources is activated, the accumulated points are cleared to zero, and step S42 needs to be reinstalled to calculate the accumulated points.

[0097] Furthermore, when the heat pump is defrosting, malfunctioning, or freezing, a backup heat source can be activated to prevent the water temperature on the heat exchanger side from dropping: ① When backup heat source 1 is at the main water line end, activate the backup heat source and deactivate when conditions are met; ② When backup heat source is at the heating end, turn the electric three-way valve to the heating end to activate the backup heat source and deactivate when conditions are met; ③ When backup heat source is at the hot water end, turn the electric three-way valve to the hot water end to activate the backup heat source and deactivate when conditions are met.

[0098] The heat pump unit of the present invention adopts an improved compressor start-up control method for initial start-up, which can effectively and fully utilize the advantages of high efficiency of heat pump in high temperature environment and stable operation of backup heat source in low temperature environment, rationally allocate energy consumption form, and improve the overall energy efficiency ratio of the system.

[0099] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A heat pump unit with a backup heat source, comprising a compressor, a four-way valve, a water source-side heat exchanger, a throttling valve, and an air-side heat exchanger connected sequentially via a refrigerant circulation pipeline; a backup heat source disposed at the outlet of the water source-side heat exchanger; a plurality of temperature sensors; and a controller electrically and / or communicatively connected to the compressor, the backup heat source, and the temperature sensors, wherein... The inlet and outlet of the water source heat exchanger, the backup heat source, and the user end water pipes form a water circulation pipeline. The high-temperature, high-pressure gaseous refrigerant generated by the compressor heats the water-side inlet water of the water source heat exchanger as it flows through it. The controller controls the start and stop of the compressor and the backup heat source using the following method: When a user has a heat demand, the current ambient temperature is obtained and compared with a preset heat pump ambient temperature start-up threshold. If the current ambient temperature is greater than or equal to the heat pump ambient temperature start-up threshold, the compressor will start and the backup heat source will not be started. If the current ambient temperature is lower than the heat pump ambient temperature start-up threshold, then the current ambient temperature is further compared with the preset backup heat source ambient temperature start-up threshold: If the current ambient temperature is lower than the start-up threshold of the backup heat source, the backup heat source will be started, and the compressor will not be started. If the current ambient temperature is greater than or equal to the backup heat source ambient temperature start-up threshold, the compressor will be started, and the monitored temperature will be further acquired. Based on the preset heating capacity integral value, the preset target temperature, and the temperature difference between the monitored temperature, the waiting time for starting the backup heat source will be determined. During the waiting time The system continuously acquires and monitors the temperature, and compares the temperature fluctuation of the (i+1)th acquired temperature with that of the ith acquired temperature with a preset temperature fluctuation threshold. If the temperature fluctuation is less than the temperature fluctuation threshold, the temperature fluctuation is ignored, and the waiting time is extended. Then turn on the backup heat source; If the temperature fluctuation is greater than or equal to the temperature fluctuation threshold, then each waiting time component is calculated in segments. The cumulative waiting time corresponding to the integral value of heating capacity is obtained. and in the cumulative waiting time Then activate the backup heat source; Wherein, the waiting time The following relationship must be satisfied: ， In the formula, This represents the preset integral value of heating capacity. This indicates the preset target temperature. The monitored temperature is indicated as follows: When the heat pump unit adopts the water temperature control mode, the target temperature is the target water temperature at the outlet of the water source heat exchanger, and the monitored temperature is the actual water temperature at the outlet of the water source heat exchanger; When the heat pump unit adopts the indoor temperature control mode, the target temperature is the target indoor temperature, and the monitored temperature is the actual indoor temperature. The segmented calculation of each waiting time component To be carried out in accordance with the following method: For temperature differences prior to the (i+1)th data acquisition where the temperature fluctuation is less than the temperature fluctuation threshold, the temperature fluctuation is ignored, and the initial temperature difference is used to calculate the waiting time component. Accumulate points by accumulating them. Among them, the cumulative points satisfy: ， In the formula, This indicates the temperature difference corresponding to the first monitored temperature when the temperature fluctuation is less than the temperature fluctuation threshold; This represents the waiting time elapsed from the start of the determined waiting period until the (i+1)th temperature monitoring data collection. The remaining integral is obtained based on the preset heating capacity integral value and the accumulated integral. The remaining waiting time component is obtained by using the remaining integral and the temperature difference corresponding to the monitoring temperature of the (i+1)th acquisition. Among them, the remaining integral satisfy: ， Remaining waiting time component satisfy: ， In the formula, This represents the remaining waiting time for the temperature difference from the (i+1)th temperature measurement corresponding to the remaining integral. This represents the temperature difference of the (i+1)th monitored temperature. Indicates the remaining integral; The cumulative waiting time Satisfy the following formula: 。 2. The heat pump unit according to claim 1, characterized in that, After determining that the current ambient temperature is greater than or equal to the backup heat source ambient temperature start-up threshold, the evaluation also includes assessing the heating capacity: The monitored temperature is obtained, the temperature difference between the preset target temperature and the monitored temperature is calculated, and the temperature difference is compared with a preset heating evaluation temperature difference threshold. If the temperature difference is less than or equal to the heating assessment temperature difference threshold, the compressor will continue to run and the backup heat source will not be activated. If the temperature difference exceeds the heating assessment temperature difference threshold, the monitored temperature is further obtained, and the waiting time for activating the backup heat source is determined based on the preset heating capacity integral value, the preset target temperature, and the temperature difference between the monitored temperature. and during the waiting time Then the backup heat source is activated.

3. The heat pump unit according to claim 2, characterized in that, It also includes correcting the preset target temperature by subtracting a fixed correction amount, and then calculating the temperature difference between the corrected target temperature and the monitored temperature, wherein the fixed correction amount... The temperature is 1~3℃.

4. The heat pump unit according to claim 1, characterized in that... It also includes a backup heat source installed at the user's water supply end and heating end, and an electric three-way valve connecting the outlet of the heat exchanger on the water source side to the user's water supply end and heating end.

5. The heat pump unit according to claim 4, characterized in that, When the backup heat source is composed of multiple sets of heating devices, the accumulated integral is reset to zero when the first set of heating devices is turned on, and the start-up judgment needs to be re-based on the monitored temperature.

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