EP3537059A1

EP3537059A1 - Heat pump water heater unit and control method and device thereof

Info

Publication number: EP3537059A1
Application number: EP16920873.3A
Authority: EP
Inventors: Dengke Zhang
Original assignee: Midea Group Co Ltd; GD Midea Heating and Ventilating Equipment Co Ltd
Current assignee: Midea Group Co Ltd; GD Midea Heating and Ventilating Equipment Co Ltd
Priority date: 2016-11-03
Filing date: 2016-11-14
Publication date: 2019-09-11
Anticipated expiration: 2036-11-14
Also published as: EP3537059A4; CN106500345B; WO2018082115A1; CN106500345A; EP3537059B1

Abstract

Disclosed are a heat pump water heater unit and a control method and device thereof. The method comprises the following steps: after receiving an off-peak electricity signal, obtaining the water temperature of a water tank (30); if the water temperature is lower than a set temperature, controlling a heat pump main machine (10) to be in a turned-on state; calculating the time needed for the water temperature of the water tank (30) to rise by a first pre-set temperature every time when the heat pump main machine (10) and an electric auxiliary heater (20) are turned on at the same time as every other first pre-set time, and recording the time as a first time; and if the first time is less than a second pre-set time, controlling the electric auxiliary heater (20) to be in a turned-on state. In the method, turning on of the electric auxiliary heater (20) is controlled according to a time that is calculated in real time and needed for the temperature of the water tank (30) to rise by a pre-set temperature every time when the heat pump main machine (10) and the electric auxiliary heater (20) are turned on at the same time, thus not only the purpose of saving energy can be achieved, but also the requirement of a user for the water temperature can be satisfied.

Description

FIELD

The present disclosure relates to a field of household appliances technology, and more particularly, to a control method of a heat pump water heater unit, a control device of a heat pump water heater unit and a heat pump water heater unit having the same.

BACKGROUND

As to on-peak and off-peak time-of-use of electricity, although electricity in off-peak hours is very cheap, total time of the off-peak hours is limited. In order to use the heat pump water heater unit as much as possible within a limited time period, and to ensure that a water temperature of the heat pump water heater unit reaches a set temperature, an electric auxiliary heater is required to be turned on at an appropriate time.
In the related art, the opening of the electric auxiliary heater is controlled according to a set water temperature. In other words, when the water temperature of the heat pump water heater unit reaches the set water temperature, the electric auxiliary heater is controlled to be turned on, and when the water temperature of the heat pump water heater unit reaches the set temperature, the electric auxiliary heater is controlled to be turned off.
However, since the heating capacity of the heat pump host may change after operating for a period of time, and the environment temperature may change during the operation, a simple calculation may cause a large deviation, thereby causing the electric auxiliary heater to be turned on in advance, which may increase energy consumption, or causing delayed opening of the electric auxiliary heater, so that the water temperature of the heat pump water heater unit cannot reach the set temperature.

SUMMARY

The present disclosure aims to solve at least one of the problems existing in the related art to at least some extent.
Accordingly, an objective of the present disclosure is to provide a control method of a heat pump water heater unit, in which turning on of an electric auxiliary heater is controlled according to a time period that is calculated in real time and is required for a temperature of a water tank to rise by a pre-set temperature when both the heat pump water heater unit and the electric auxiliary heater are turned on, thus not only a purpose of saving energy can be achieved, but also the requirement of a user for the water temperature can be satisfied.
Another objective of the present disclosure is to provide a control device of a heat pump water heater unit.
Another objective of the present disclosure is to provide a heat pump water heater unit.
To achieve the above objectives, embodiments of an aspect of the present disclosure provide a control method of a heat pump water heater unit. The heat pump water heater unit includes a heat pump host, an electric auxiliary heater and a water tank. The control method includes: after receiving an off-peak electricity signal, obtaining a water temperature of the water tank and determining whether the water temperature of the water tank is less than a set temperature; when the water temperature is less than the set temperature, controlling the heat pump host to be in a turned-on state; calculating a time period required for the water temperature of the water tank to rise by a first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period, and recording the time period as a first time period; determining whether the first time period is less than a second pre-set time period; and when the first time period is less than the second pre-set time period, controlling the electric auxiliary heater to be in the turned-on state.
With the control method of a heat pump water heater unit according to embodiments of the present disclosure, the water temperature of the water tank is obtained after receiving the off-peak electricity signal. When the water temperature of the water tank is less than the set temperature, the heat pump host is controlled to be in the turned-on state. The time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on is calculated every first pre-set time period, and the time period is recorded as the first time period. When the first time period is less than the second pre-set time period, the electric auxiliary heater is controlled to be in the turned-on state. With the method, the opening of the electric auxiliary heater is controlled according to the time period calculated in real time and required for the water temperature of the tank to raise by the set temperature when both the heat pump host and the electric auxiliary heater are turned on, thus not only a purpose of saving energy can be achieved, but also requirement of a user for the water temperature can be satisfied.
According to an embodiment of the present disclosure, calculating period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period includes: determining whether the set temperature is less than a maximum heating temperature of the heat pump host at a current outdoor ambient temperature; when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, calculating a remaining total time period of the off-peak electricity according to the first pre-set time period, and calculating the first time period according to the remaining total time period of the off-peak electricity, the set temperature, and the water temperature of the water tank; when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, calculating the remaining total time period of the off-peak electricity according to the first pre-set time period and a time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, and calculating the first time period according to the remaining total time period of the off-peak electricity, the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and the water temperature of the water tank.
According to an embodiment of the present disclosure, when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the first time period is calculated according to a following formula: $t = (H * 60 - TM * n) / (TS - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, TM is the first pre-set time period, n is a number of calculation times, TS is the set temperature, and T5 is the water temperature of the water tank.
According to another embodiment of the present disclosure, when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the first time period is calculated according to a following formula: $t = [H * 60 - t_{de} * (TS - Tstop) - n * TM] / (Tstop - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, and t_de is the time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, and the TS is the set temperature, Tstop is the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, n is a number of calculation times, TM is the first pre-set time period, and T5 is the water temperature of the water tank.
According to an embodiment of the present disclosure, the second pre-set time period is a minimum time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on at the current outdoor ambient temperature.
According to an embodiment of the present disclosure, after controlling a the electric auxiliary heater to be in the turned-on state, the control method further includes: when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, controlling both the heat pump host and the electric auxiliary heater to be in a turned-off state when the water temperature of the water tank is greater than or equal to the set temperature; when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, controlling the heat pump host to be in the turned-off state when the water temperature of the water tank is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and controlling the electric auxiliary heater to be in the turned-off state when the water temperature of the water tank is greater than or equal to the set temperature.
To achieve the above objectives, embodiments of another aspect of the present disclosure provide a control device of a heat pump water heater unit. The heat pump water heater unit includes a heat pump host, an electric auxiliary heater and a water tank. The control device includes: a temperature acquisition module, configured to acquire a water temperature of the water tank; a control module, in which the control module is respectively coupled to the temperature acquisition module, the heat pump host and the electric auxiliary heater. The control module is configured to determine whether the water temperature of the water tank is less than a set temperature after receiving an off-peak electricity signal. When the water temperature of the water tank is less than the set temperature, the control module is configured to control the heat pump host to be in a turned-on state, to calculate a time period required for the water temperature of the water tank to rise by a first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period, to record the time period as the first time period, to determine whether the first time period is less than a second pre-set time period, and to control the electric auxiliary heater to be in the turned-on state when the first time period is less than the second pre-set time period.
With the control device of a heat pump water heater unit according to embodiments of the present disclosure, the control module determines whether the water temperature of the water tank is less than the set temperature after receiving the off-peak electricity signal. When the water temperature of the water tank is less than the set temperature, the control module controls the heat pump host to be in the turned-on state, calculates the time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period, and records the time period as the first time period. When the first time period is less than the second pre-set time period, the control module controls the electric auxiliary heater to be in the turned-on state. The device controls the opening of the electric auxiliary heater according to the time period calculated in real time and required for the water temperature of the tank to raise by the set temperature when both the heat pump host and the electric auxiliary heater are turned on, thus not only a purpose of saving energy can be achieved, but also requirement of a user for the water temperature can be satisfied.
According to an embodiment of the present disclosure, when the control module calculates the time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period, the control module is configured to determine whether the set temperature is less than a maximum heating temperature of the heat pump host at a current outdoor ambient temperature; when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate a remaining total time period of the off-peak electricity according to the first pre-set time period, and to calculate the first time period according to the remaining total time period of the off-peak electricity, the set temperature, and the water temperature of the water tank; when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate the remaining total time period of the off-peak electricity according to the first pre-set time period and a time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, and to calculate the first time period according to the remaining total time period of the off-peak electricity, the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and the water temperature of the water tank.
According to an embodiment of the present disclosure, when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate the first time period according to a following formula: $t = (H * 60 - TM * n) / (TS - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, TM is the first pre-set time period, n is a number of calculation times, TS is the set temperature, and T5 is the water temperature of the water tank.
According to another embodiment of the present disclosure, when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate the first time period according to a following formula: $t = [H * 60 - t_{de} * (TS - Tstop) - n * TM] / (Tstop - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, and t_de is the time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, the TS is the set temperature, Tstop is the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, n is a number of calculation times, TM is the first pre-set time period, and T5 is the water temperature of the water tank.
According to an embodiment of the present disclosure, the second pre-set time period is a minimum time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on at the current outdoor ambient temperature.
According to an embodiment of the present disclosure, after controlling the electric auxiliary heater to be in the turned-on state, when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to control both the heat pump host and the electric auxiliary heater to be in a turned-off state when the water temperature of the water tank is greater than or equal to the set temperature; when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to control the heat pump host to be in the turned-off state when the water temperature of the water tank is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and to control the electric auxiliary heater to be in the turned-off state when the water temperature of the water tank is greater than or equal to the set temperature.
In addition, embodiments of the present disclosure also provide a heat pump water heater unit including the above-described control device of the heat pump water heater unit.
The heat pump water heater unit according to embodiments of the present disclosure controls the opening of the electric auxiliary heater through the above control device according to the time period calculated in real time and required for the water temperature of the tank to raise by the set temperature when both the heat pump host and the electric auxiliary heater are turned on, thus not only a purpose of saving energy can be achieved, but also requirement of a user for the water temperature can be satisfied.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a flow chart of a control method of a heat pump water heater unit according to an embodiment of the present disclosure.
Fig. 2 is a schematic diagram illustrating a relationship between an outdoor ambient temperature and a maximum heating temperature of the heat pump host according to an embodiment of the present disclosure.
Fig. 3 is a schematic diagram illustrating the logic of a control method of a heat pump water heater unit according to an embodiment of the present disclosure.
Fig. 4 is a diagram illustrating the logic of a control method of a heat pump water heater unit according to another embodiment of the present disclosure.
Fig. 5 is a schematic diagram illustrating a relationship between an outdoor ambient temperature and a second pre-set time period according to an embodiment of the present disclosure.
Fig. 6 is a flow chart of a control method of a heat pump water heater unit according to an embodiment of the present disclosure.
Fig. 7 is a schematic diagram illustrating the structure of a heat pump water heater unit according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present disclosure. Examples of the embodiments of the present disclosure will be shown in drawings, in which the same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions. The embodiments described herein according to drawings are explanatory and illustrative, not construed to limit the present disclosure.
A control method of a heat pump water heater unit, a control device of a heat pump water heater unit, and a heat pump water heater unit having the same according to embodiments of the present disclosure will be described with reference to accompanying drawings.
Fig. 1 is a flow chart of a control method of a heat pump water heater unit according to embodiments of the present disclosure. In the embodiments of the present disclosure, the heat pump water heater unit may include a heat pump host, an electric auxiliary heater and a water tank.
As illustrated in Fig. 1, the control method of the heat pump water heater unit may include following operations.
At block S1, after receiving an off-peak electricity signal, a water temperature of the water tank is obtained and it is determined whether the water temperature of the water tank is less than a set temperature. The set temperature is a water temperature required by a user. The set temperature can be manually set according to capacity heating water of the heat pump water heater unit and practical requirements of the user. For example, the set temperature can be in a range of 38°C to 75°C, and a default value of the set temperature can be 55°C.
At block S2, when the water temperature is less than the set temperature, the heat pump host is controlled to be in a turned-on state.
At block S3, a time period required for the water temperature of the water tank to rise by a first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period is calculated and recorded as a first time period. The first pre-set time period and the first pre-set temperature may be calibrated according to actual conditions. For example, the first pre-set time period may be in a range of 1 min to 10 min, and the first pre-set temperature may be in a range of 1°C to 2°C.
According to an embodiment of the present disclosure, calculating the time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period includes: determining whether the set temperature is less than a maximum heating temperature of the heat pump host at a current outdoor ambient temperature; when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, calculating a remaining total time period of the off-peak electricity according to the first pre-set time period, and calculating the first time period according to the remaining total time period of the off-peak electricity, the set temperature, and the water temperature of the water tank; when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, calculating the remaining total time period of the off-peak electricity according to the time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone and the first pre-set time period, and calculating the first time period according to the remaining total time period of the off-peak electricity, the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and the water temperature of the water tank.
According to an embodiment of the present disclosure, when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the first time period may be calculated according to following formula (1): $t = (H * 60 - TM * n) / (TS - T 5)$
where t is the first time period, H is a total time period of the off-peak electricity. H can be set by the user through timing or be set according to a time period actually provided by the power supply bureau, a value of H is generally in a range of 1 to 8 hours. TM is the first pre-set time period, n is a number of calculation times, TS is the set temperature, and T5 is the water temperature of the water tank.
According to another embodiment of the present disclosure, when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the first time period may be calculated according to following formula (2): $t = [H * 60 - t_{de} * (TS - Tstop) - n * TM] / (Tstop - T 5)$
where t_de is the time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone. Tstop is the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, i.e., a maximum temperature that the water in the water tank can be heated by the heat pump host under different outdoor ambient temperature T4. As illustrated in Fig. 2, Tstopg1, Tstopg2, ..., Tstopg13 are the maximum heating temperature of the heat pump host under different outdoor ambient temperature T4. For example, when 37°C≤T4<43°C, the maximum heating temperature of the heat pump host is Tstopg1, when -14°C≤T4<-10°C, the maximum heating temperature of the heat pump host is Tstopg13, when the outdoor ambient temperature T4 is greater than 43°Cor lower than -14°C, the heat pump host does not work.
In detail, as illustrated in Fig. 3 and Fig. 4, after receiving the off-peak electricity signal, the water temperature T5 of the water tank is obtained by a temperature sensor in real time, and it is determined whether the water temperature T5 of the water tank is less than the set temperature TS, or less than the set temperature TS - a startup return difference temperature, in which the startup return difference temperature can be calibrated according to actual situation. For example, the startup return difference temperature can be in a range of 1 °C to 10 °C, and a default startup return difference temperature can be 5 °C. When the water temperature T5 of the water tank is less than the set temperature TS, it indicates that the current water temperature cannot satisfy the user's demand. At this time, it is required to turn on the heat pump host, that is, to control a compressor in the heat pump host to be turned on to heat the water in the water tank.
After the heat pump host is turned on, the time period required for the water temperature of the water tank to rise by the first pre-set temperature (e.g. 1°C) every time when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period (e.g. 5 min) is calculated according to the current heating condition, and the time period is recorded as the first time period t. When calculating the first time period t, a calculation manner of the first time period t is selected according to a relationship between the set temperature TS and the maximum heating temperature Tstop of the heat pump host at the current outdoor ambient temperature, so as to ensure accuracy of calculating the first time period t.
As illustrated in Fig. 3, when TS < Tstop, there may be two kinds of heating conditions. One is that the water in the water tank is able to be heated to the set temperature TS within the total time period H of the off-peak electricity by turning on the heat pump host alone, and the other is that the water in the water tank is able to be heated to the set temperature TS within the total time period H of the off-peak electricity by turning on the heat pump host alone for a while, then turning on both the electric auxiliary heater and the heat pump host. Therefore, when calculating the first time period t, the remaining total time period H' of the off-peak electricity may be first calculated according to the first pre-set time period TM. For example, the remaining total time period of the off-peak electricity H'=H^∗60-n^∗TM. Then the first time period t may be calculated according to the remaining total time period H' of the off-peak electricity, the set temperature TS, and the water temperature T5 of the water tank. For example, the first time period $t = H' / (TS - T 5) = (H * 60 - n * TM) / (TS - T 5) .$
As illustrated in Fig. 4, when TS≥Tstop, the case that that the water of the water tank can be heated to the set temperature TS within the total time period H of the off-peak electricity when the heat pump host is turned on alone may not occur, and a case that, when both the heat pump host and the electric auxiliary heater is turned on, the water temperature of the water tank has not reached the set temperature TS while a temperature of the heat pump host has reached Tstop. At this time, the electric auxiliary heater is required to be turned on alone to continue heating the water in the water tank, such that the water temperature of the water tank can be heated to the set temperature TS within the total time period H of the off-peak electricity. That is, when TS≥Tstop, there may be two kinds of heating conditions. One is turning on the heat pump host alone for a while, then turning on both the electric auxiliary heater and the heat pump host. The other is turning on the heat pump host alone for a while, then turning on both the electric auxiliary heater and the heat pump host for a while, and finally controlling the electric auxiliary heater alone to be turned on for a while. Therefore, in this case, when calculating the first time period t, the heating condition when the electric auxiliary heater is turned on alone may be taken into consideration. For example, the remaining total time period H' of the off-peak electricity can be calculated according to a time period t_de required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone. For example, the remaining total time period H' of the off-peak electricity=H^∗60-t_de ^∗(TS-Tstop)-n^∗TM. Then, the first time period t can be calculated according to the remaining total time period H' of the off-peak electricity, the maximum heating temperature Tstop of the heat pump host at the current outdoor ambient temperature, the water temperature T5 of the water tank. For example, the first time period $t = H' / (Tstop - T 5) = (H * 60 - t_{de} * (TS - Tstop) - n * TM) / (Tstop - T 5) .$
At block S4, it is determined whether the first time period is less than a second pre-set time period.
The second pre-set time period is a pre-set minimum time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on. Considering that the outdoor ambient temperature T4 has a certain influence on the heating capacity of the heat pump host, that is, when both the heat pump host and the electric auxiliary heater are turned on at different outdoor ambient temperatures T4, the time periods required for the water temperature T5 of the water tank to rise by the first pre-set temperature are different. Therefore, the minimum time period required for the water temperature T5 of the water tank to rise by the first pre-set temperature can be determined according to the current outdoor ambient temperature T4.
That is, according to an embodiment of the present disclosure, the second pre-set time period may be a minimum time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on at the current outdoor ambient temperature.

In order to simplify the calculation, as illustrated in Fig. 5, the outdoor ambient temperature T4 may be partitioned, and the second pre-set time periods in each partition are the same, as shown in Table 1:

Table 1

Code	Meaning	parameter value
t_hd1e	A minimum time period required for T5 to rise by 1 °C when both the heat pump host and the electric auxiliary heater are turned on	3.1min
t_hd2e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	3.0min
t_hd3e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	3.2min
t_hd4e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	3.4min
t_hd5e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	3.5min
t_hd6e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	3.6min
t_hd7e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	3.7min
t_hd8e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	3.9min
t_hd9e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	4.0min
t_hd10e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	4.2min
t_hd11e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	4.5min
t_hd12e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	4.8min
t_hd13e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	5.4min
t_hd14e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	6.0min
t_hd15e	A minimum time period required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on	6.4min
t_de	A minimum time period required for T5 to rise by 1°C when the electric auxiliary heater is turned on alone	8.6min

In Table 1, t_hd1e, th_d1e, ..., t_hd15e are respectively the minimum time periods (i.e. the second pre-set time periods) required for T5 to rise by 1°C when both the heat pump host and the electric auxiliary heater are turned on at different outdoor ambient temperatures corresponding to Fig. 5. For example, when the outdoor ambient temperature T4 < -3°C, the second pre-set time period t_hd15e is 6.4 min; when 18°C< T4 < 21°C, the second pre-set time period t_hd7e is 3.7 min.
At block S5, when the first time period is less than the second pre-set time period, the electric auxiliary heater is controlled to be in the turned-on state.
In detail, assuming that the current outdoor ambient temperature T4 is between 35 °C and 37 °C, the second pre-set time period t_hd1e can be obtained as 3.1min according to Table 1, and the maximum heating temperature of the heat pump host can be obtained as Tstopg 2 according to Fig. 2. In addition, assuming that the current number of calculations times is n=10, when TS<Tstopg2, the first time period t can be calculated by the above formula (1): t=(H^∗60-TM^∗10)/(TS-T5). Then it is determined whether the first time period t is less than the second pre-set time period t_hd1e. When the first time period t is less than the second pre-set time period t_hd1e, the electric auxiliary heater is controlled to be in the turned-on state. At this time, both the heat pump host and the electric auxiliary heater heat the water in the water tank. When TS≥Tstopg2, the first time period t can be calculated by the above formula (2): t=[H^∗60-t_de ^∗(TS-Tstopg2)-10^∗TM]/(Tstopg2-T5). Then it is determined whether the first time period t is less than the second pre-set time period t_hd1e. When the first time period t is less than the second pre-set time period t_hd1e, the electric auxiliary heater is controlled to be in the turned-on state. At this time, both the heat pump host and the electric auxiliary heater heat the water in the water tank.
Further, according to an embodiment of the present disclosure, after controlling the electric auxiliary heater to be in the turned-on state, the method further includes: when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, controlling both the heat pump host and the electric auxiliary heater to be in a turned-off state when the water temperature in the water tank is greater than or equal to the set temperature; when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, controlling the heat pump host to be in the turned-off state when the water temperature of the water tank is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and controlling the electric auxiliary heater to be in the turned-off state when the water temperature of the water tank is greater than or equal to the set temperature.
In detail, as illustrated in Fig. 3, when TS<Tstop, during a process that both the heat pump host and the electric auxiliary heater are turned on to heat the water in the water tank, when the water temperature T5 of the water tank is greater than or equal to the set temperature TS, both the heat pump host and the electric auxiliary heater can be controlled to be in the turned-off state. As illustrated in Fig. 4, when TS≥Tstop, during a process that both the heat pump host and the electric auxiliary heater are turned on to heat the water in the water tank, when the water temperature T5 of the water tank is greater than or equal to the maximum heating temperature Tstop of the heat pump host at the current outdoor ambient temperature, the heat pump host can be controlled to be in the turned-off state. That is, when the time period reaches H^∗60-(TS-Tstop)^∗t_de, the heat pump host is controlled to be in the turned-off state. Then, the electric auxiliary heater heats the water of the water tank alone until the water temperature T5 of the water tank is greater than or equal to the set temperature TS, and then the electric auxiliary heater is controlled to be in the turned-off state.
Therefore, with the control method of the heat pump water heater unit according to the embodiments of the present disclosure, an exact opening time point of the electric auxiliary heater is calculated based on a current heating rate, thus not only achieving a purpose of energy saving, but also satisfying the user's requirement by heating the water in the water tank to the set temperature within the total time period of the off-peak electricity.
In order to make the present disclosure more clearly understood by those skilled in the art, Fig. 6 is a flow chart of a control method of a heat pump water heater unit according to an embodiment of the present disclosure. As illustrated in Fig. 6, the control method of the heat pump water heater unit may include the following operations.
At block S101, after receiving an off-peak electricity signal, a water temperature T5 of the water tank is obtained.
At block S102, it is determined whether T5 < TS holds. If yes, the operation at block S103 is performed, otherwise, the operation at block S101 is performed.
At block S103, the heat pump host is controlled to be in a turned-on state.
At block S104, it is determined whether TS<Tstop holds. If yes, the operation at block S105 is performed, otherwise, the operation at block S110 is performed.
At block S105, the first time period t is calculated according to the formula $t = (H * 60 - TM * n) / (TS - T 5) .$
At block S106, it is determined whether t<t_hdie holds, where t_hdie is the second pre-set time period at the current outdoor ambient temperature T4. If yes, the operation at block S107 is performed, otherwise, the operation at block S105 is performed.
At block S107, the electric auxiliary heater is controlled to be in the turned-on state.
At block S108, it is determined whether T5≥TS holds. If yes, the operation at block S109 is performed otherwise, the operation at block S107 is performed.
At block S109, both the heat pump host and the electric auxiliary heater are turned off.
At block S110, the first time period t is calculated according to the formula $t = [H * 60 - t_{de} * (TS - Tstop) - n * TM] / (Tstop - T 5) .$
At block S111, it is determined whether t<t_hdie holds. If yes, the operation at block S112 is performed otherwise, the operation at block S110 is performed.
At block S112, the electric auxiliary heater is controlled to be in the turned-on state.
At block S113, it is determined whether T5≥Tstop holds. If yes, the operation at block S114 is performed otherwise, the operation at block S112 is performed.
At block S114, the heat pump host is controlled to be in a turned-off state.
At block S115, it is determined whether T5≥TS holds. If yes, the operation at block S116 is performed otherwise, the operation at block S114 is performed.
At block S116, the electric auxiliary heater is controlled to be in the turned-off state.
In conclusion, with the control method of the heat pump water heater unit according to the embodiments of the present disclosure, the water temperature of the water tank is obtained after receiving the off-peak electricity signal. When the water temperature of the water tank is less than the set temperature, the heat pump host is controlled to be in the turned-on state. The time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on is calculated every first pre-set time period, and the time period is recorded as the first time period. When the first time period is less than the second pre-set time period, the electric auxiliary heater is controlled to be in the turned-on state. With the method, the opening of the electric auxiliary heater is controlled according to the time period calculated in real time and required for the water temperature of the tank to raise by the set temperature when both the heat pump host and the electric auxiliary heater are turned on, thus not only a purpose of saving energy can be achieved, but also the requirement of the user for the water temperature can be satisfied.
Fig. 7 is a schematic diagram illustrating the structure of a heat pump water heater unit according to an embodiment of the present disclosure. As illustrated in Fig. 7, the heat pump water heater unit may include a heat pump host 10, an electric auxiliary heater 20 and a water tank 30. The electric auxiliary heater 20 may include one or more heating tubes.
As illustrated in Fig. 7, a control device of the heat pump water heater unit may include a temperature acquisition module 40 and a control module 50. The temperature acquisition module 40 is configured to acquire a water temperature of a water tank 30. The control module 50 is respectively coupled to the temperature acquisition module 40, the heat pump host 10 and the electric auxiliary heater 20. The control module 50 is configured to determine whether the water temperature of the water tank 30 is less than a set temperature after receiving an off-peak electricity signal. When the water temperature is less than the set temperature, the control module 50 controls the heat pump host 10 to be in a turned-on state, and calculates a time period required for the water temperature of the water tank to rise by a first pre-set temperature when both the heat pump host 10 and the electric auxiliary heater 20 are turned on every first pre-set time period, records the time period as the first time period, and determines whether the first time period is less than a second pre-set time period. When the first time period is less than the second pre-set time period, the control module 50 controls the electric auxiliary heater 20 to be in the turned-on state, .
According to an embodiment of the present disclosure, when the control module 50 calculates the time period required for the water temperature of the water tank 30 to rise by the first pre-set temperature when both the heat pump host 10 and the electric auxiliary heater 20 are turned on every first pre-set time period, the control module 50 determines whether the set temperature is less than a maximum heating temperature of the heat pump host 10 at a current outdoor ambient temperature. When the set temperature is less than the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, the control module 50 calculates a remaining total time period of the off-peak electricity according to the first pre-set time period, and calculates the first time period according to the remaining total time period of the off-peak electricity, the set temperature, and the water temperature of the water tank 30. When the set temperature is greater than or equal to the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, the control module 50 calculates the remaining total time period of the off-peak electricity according to the time period required for the water temperature of the water tank 30 to rise by the first pre-set temperature when the electric auxiliary heater 20 is turned on alone and the first pre-set time period, and calculates the first time period according to the remaining total time period of the off-peak electricity, the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, and the water temperature of the water tank 30.
According to an embodiment of the present disclosure, when the set temperature is less than the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, the control module 50 can calculates the first time period t according to above formula (1).
According to another embodiment of the present disclosure, when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, the control module 50 can calculates the first time period t according to above formula (2).
According to an embodiment of the present disclosure, the second pre-set time period is a minimum time period required for the water temperature of the water tank 30 to rise by the first pre-set temperature when both the heat pump host 10 and the electric auxiliary heater 20 are turned on at the current outdoor ambient temperature.
According to an embodiment of the present disclosure, after the electric auxiliary heater 20 is controlled to be in the turned-on state, when the set temperature is less than the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, the control module 50 controls both the heat pump host 10 and the electric auxiliary heater 20 to be in a turned-off state when the water temperature of the water tank 30 is greater than or equal to the set temperature. When the set temperature is greater than or equal to the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, the control module 50 controls the heat pump host 10 to be in the turned-off state when the water temperature of the water tank 30 is greater than or equal to the maximum heating temperature of the heat pump host 10 at the current outdoor ambient temperature, and controls the electric auxiliary heater 20 to be in the turned-off state when the water temperature of the water tank 30 is greater than or equal to the set temperature.
It should be noted that, details not disclosed in the control device of the heat pump water heater unit of the present disclosure may refer to the details disclosed in the control method of the heat pump water heater unit of the present disclosure, and details are not described herein again.
In conclusion, with the control device of the heat pump water heater unit according to the embodiments of the present disclosure, the control module determines whether the water temperature of the water tank is less than the set temperature after receiving the off-peak electricity signal. When the water temperature is less than the set temperature, the control module controls the heat pump host to be in the turned-on state. The time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on is calculated every first pre-set time period, and the time period is recorded as the first time period. When the first time period is less than the second pre-set time period, the control module controls the electric auxiliary heater to be in the turned-on state. The device controls the opening of the electric auxiliary heater according to the time period calculated in real time and required for the water temperature of the tank to raise by the set temperature when both the heat pump host and the electric auxiliary heater are turned on, thus not only a purpose of saving energy can be achieved, but also requirement of a user for the water temperature can be satisfied.
Further, an embodiment of the present disclosure also provides a heat pump water heater unit including the above-described control device of the heat pump water heater unit. The heat pump water heater unit may be in a separated structure or an integral structure, and may be a water circulation unit or a refrigerant circulation unit. For example, the structure of the heat pump water heater unit may be as illustrated in Fig. 7, and the specific structure will not be limited herein.
The heat pump water heater unit of the embodiments of the present disclosure controls the opening of the electric auxiliary heater by the above control device by the time period needed for the water temperature of the tank to raise by the set temperature when the heat pump host and the electric auxiliary heater are turned on at the same time in real-time, thus not only the purpose of saving energy can be achieved, but also the requirement of a user for the water temperature can be satisfied.
In the description of the present disclosure, it is to be understood that, terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "over", "below", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "in", "out", "clockwise", "anti-clockwise", "axial", "radial" and "circumference" refer to the orientation and location relations as shown in the drawings. These relative terms are for convenience of describing the present disclosure and for simplifying the description, and do not intend to indicate or imply that the device or the elements must have a specific orientation, be constructed and operated in a particular orientation,, which could not to be understood to the limitation of the present disclosure.
In addition, terms such as "first" and "second" are used herein for purposes of description and are not intended to indicate or imply relative importance or significance. Furthermore, the feature defined with "first" and "second" may comprise one or more this feature distinctly or implicitly. In the description of the present disclosure, "a plurality of' means two or more than two, such as two or three, unless specified otherwise.
In the present disclosure, unless specified or limited otherwise, the terms "mounted," "connected," "coupled" and "fixed" and the like are understood broadly, and may be, for example, fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections, may also be direct connections or indirect connections via intermediary, and further can be inner communications or interaction relations of two components, which can be understood by those skilled in the art according to t specific situations.
In the present disclosure, unless specified or limited otherwise, a first feature is "on" or "below" a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature is "on", "above", "over" a second feature may include an embodiment in which the first feature is right or obliquely "on," "above," or "on top of' the second feature, or just means that the first feature is at a height higher than that of the second feature. The first feature is "below", "under" or "on bottom of' a second feature may include an embodiment in which the first feature is right or obliquely "below," "under," or "on bottom of' the second feature, or just means that the first feature is at a height lower than that of the second feature.
In the description of the present disclosure, reference throughout this specification to "an embodiment," "some embodiments," "an example," "a specific example," or "some examples," means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, the appearances of the phrases such as "in some embodiments," "in one embodiment", "in an embodiment", "in another example," "in an example," "in a specific example," or "in some examples," in various places throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples. Those skilled in the art can combine different embodiments or examples described in the specification and the features of the different embodiments or examples without departing from the scope of the present disclosure without contracting each other.
Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present disclosure, and changes, alternatives, and modifications can be made in the embodiments without departing from scope of the present disclosure.

Claims

A control method of a heat pump water heater unit, wherein the heat pump water heater unit comprises a heat pump host, an electric auxiliary heater and a water tank, the control method comprises:
after receiving an off-peak electricity signal, obtaining a water temperature of the water tank and determining whether the water temperature of the water tank is less than a set temperature;

when the water temperature is less than the set temperature, controlling the heat pump host to be in a turned-on state;

calculating a time period required for the water temperature of the water tank to rise by a first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period, and recording the time period as a first time period;

determining whether the first time period is less than a second pre-set time period; and

when the first time period is less than the second pre-set time period, controlling the electric auxiliary heater to be in the turned-on state.
The control method according to claim 1, wherein calculating the time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period comprises:
determining whether the set temperature is less than a maximum heating temperature of the heat pump host at a current outdoor ambient temperature;

when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, calculating a remaining total time period of the off-peak electricity according to the first pre-set time period, and calculating the first time period according to the remaining total time period of the off-peak electricity, the set temperature, and the water temperature of the water tank;

when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, calculating the remaining total time period of the off-peak electricity according to the first pre-set time period and a time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, and calculating the first time period according to the remaining total time period of the off-peak electricity, the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and the water temperature of the water tank.
The control method according to claim 2, wherein, when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the first time period is calculated according to a following formula: $t = (H * 60 - TM * n) / (TS - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, TM is the first pre-set time period, n is a number of calculation times, TS is the set temperature, and T5 is the water temperature of the water tank.
The control method according to claim 2, wherein, when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the first time period is calculated according to a following formula: $t = [H * 60 - t_{de} * (TS - Tstop) - n * TM] / (Tstop - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, t_de is the time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, TS is the set temperature, Tstop is the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, n is a number of calculation times, TM is the first pre-set time period, and T5 is the water temperature of the water tank.
The control method according to any one of claims 1-4, wherein, the second pre-set time period is a minimum time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on at the current outdoor ambient temperature.
The control method according to any one of claims 2-4, after controlling the electric auxiliary heater to be in the turned-on state, further comprising:
when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, controlling both the heat pump host and the electric auxiliary heater to be in a turned-off state when the water temperature of the water tank is greater than or equal to the set temperature; and

when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, controlling the heat pump host to be in the turned-off state when the water temperature of the water tank is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and controlling the electric auxiliary heater to be in the turned-off state when the water temperature of the water tank is greater than or equal to the set temperature.
A control device of a heat pump water heater unit, wherein the heat pump water heater unit comprises a heat pump host, an electric auxiliary heater and a water tank, the control device comprises:
a temperature acquisition module, configured to acquire a water temperature of the water tank; and

a control module, wherein the control module is respectively coupled to the temperature acquisition module, the heat pump host and the electric auxiliary heater, the control module is configured to determine whether the water temperature of the water tank is less than a set temperature after receiving an off-peak electricity signal, to control the heat pump host to be in a turned-on state when the water temperature of the water tank is less than the set temperature, to calculate a time period required for the water temperature of the water tank to rise by a first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period, to record the time period as the first time period, to determine whether the first time period is less than a second pre-set time period, and to control the electric auxiliary heater to be in the turned-on state when the first time period is less than the second pre-set time period.
The control device according to claim 7, wherein when the control module calculates the time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on every first pre-set time period,
the control module is configured to determine whether the set temperature is less than a maximum heating temperature of the heat pump host at a current outdoor ambient temperature;
when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate a remaining total time period of the off-peak electricity according to the first pre-set time period, and to calculate the first time period according to the remaining total time period of the off-peak electricity, the set temperature, and the water temperature of the water tank; and
when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate the remaining total time period of the off-peak electricity according to the first pre-set time period and a time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, and to calculate the first time period according to the remaining total time period of the off-peak electricity, the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and the water temperature of the water tank.
The control device according to claim 8, wherein, when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate the first time period according to a following formula: $t = (H * 60 - TM * n) / (TS - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, TM is the first pre-set time period, n is a number of calculation times, TS is the set temperature, and T5 is the water temperature of the water tank.
The control device according to claim 8, wherein, when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to calculate the first time period according to a following formula: $t = [H * 60 - t_{de} * (TS - Tstop) - n * TM] / (Tstop - T 5),$
where t is the first time period, H is a total time period of the off-peak electricity, t_de is the time period required for the water temperature of the water tank to rise by the first pre-set temperature when the electric auxiliary heater is turned on alone, TS is the set temperature, Tstop is the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, n is a number of calculation times, TM is the first pre-set time period, and T5 is the water temperature of the water tank.
The control device according to any one of claims 7-10, wherein, the second pre-set time period is a minimum time period required for the water temperature of the water tank to rise by the first pre-set temperature when both the heat pump host and the electric auxiliary heater are turned on at the current outdoor ambient temperature.
The control device according to any one of claims 8-10, wherein, after controlling the electric auxiliary heater to be in the turned-on state,
when the set temperature is less than the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to control both the heat pump host and the electric auxiliary heater to be in a turned-off state when the water temperature of the water tank is greater than or equal to the set temperature; and
when the set temperature is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, the control module is configured to control the heat pump host to be in the turned-off state when the water temperature of the water tank is greater than or equal to the maximum heating temperature of the heat pump host at the current outdoor ambient temperature, and to control the electric auxiliary heater to be in the turned-off state when the water temperature of the water tank is greater than or equal to the set temperature.
A heat pump water heater unit, comprising the control device of a heat pump water heater unit according to any one of claims 7-12.