Control method for preventing heat pump system from being frozen in low-temperature environment

Abstract

The invention discloses a control method for preventing a heat pump system from being frozen in a low-temperature environment, which comprises the following steps: after a main control system is powered on, a second circulating pump of a controller is started, and a standby battery of an auxiliary system is charged; the auxiliary system controls the first circulating pump, the drainage valve and the water supplementing valve according to the environment temperature and the return water temperature. When power failure occurs in the low-temperature environment, water circulation can be kept through the auxiliary system, and the drainage function is started when the temperature of return water is too low or the electric quantity of a standby battery is insufficient, so that the heat pump system is prevented from being damaged by freezing.

Description

Technical Field

[0001] The invention relates to a control method for preventing a heat pump system from being frozen in a low-temperature environment. Background Art

[0002] Among the water machines, air conditioning heat pumps and other products currently on the market, the circulating water pump is a vital part of the heating system, which can circulate the water in the system from the low-temperature and high-pressure area to the high-temperature and low-pressure area, thereby ensuring the flow and pressure of the water in the system. During use in a low-temperature environment, there may be power outages, and damage to the circulating pump and water flow switch. During the power outage stage and when the circulating pump and water flow switch are damaged, the water in the entire system cannot be repeatedly circulated. In the case of continued low temperatures, the various components in the system (heat exchange system) will freeze due to the low temperature. Summary of the invention

[0003] In view of the above problems, the present invention provides a control method for preventing a heat pump system from being frozen in a low temperature environment, which effectively solves the problems pointed out in the background technology.

[0004] The technical solution adopted by the present invention is:

[0005] A control method for preventing a heat pump system from being frozen in a low temperature environment, the heat pump system comprising a main control system and an auxiliary system, a first circulation pump, a second circulation pump and a drain valve connected in series are arranged on a circulation water circuit of the heat pump system, a water replenishment valve is arranged on a water replenishment water circuit of the heat pump system, the main control system controls the second circulation pump and the water replenishment valve, the auxiliary system controls the first circulation pump, the drain valve and the water replenishment valve, the auxiliary system is provided with a backup battery, and the control method is as follows:

[0006] Condition 1) After the heat pump system is powered on, the main control system detects the ambient temperature and return water temperature.

[0007] Condition 2) After the heat pump system is powered on, the main control system detects the ambient temperature and return water temperature.

[0008] ​​Condition 3) After the heat pump system is powered on, the main control system detects the ambient temperature and return water temperature.

[0009] Condition 4) During the operation of the heat pump system, the main control system monitors the ambient temperature and return water temperature in real time. When the ambient temperature is less than H1, the return water temperature is less than Y2, and there is no water flow and the display state is Z2, the following control is performed:

[0010] 41) The auxiliary system sends the water flow status data detected by the auxiliary system to the main control system. If there is water flow, the status X1 is displayed, and the main control system displays that the water flow switch of the main control system is faulty. If there is no water flow, the status X2 is displayed, and the operation of the first circulation pump is controlled by the auxiliary system;

[0011] 42) When the first circulation pump is turned on, if the main control system detects water flow, it displays state Z1, indicating that the second circulation pump is faulty, and the main control system reports the fault. When the fault is not eliminated, if the return water temperature is ≤ Y3, the first circulation pump is controlled to be turned off, and the drain valve is controlled to operate for drainage, and the water supply valve is controlled to be closed. When the main control system detects no water flow and displays state Z2, the drain valve is controlled to be closed;

[0012] Condition 5) During the operation of the heat pump system, if the main control system is powered off, the auxiliary system will detect the ambient temperature and return water temperature and perform the following control:

[0013] 51) If the ambient temperature is ≥H2 and the return water temperature is ≥Y1, the first circulation pump is controlled not to run;

[0014] 52) If the ambient temperature is ≤H2, Y3<return water temperature ≤Y2, the first circulation pump is controlled to operate;

[0015] 53) If the ambient temperature is ≤H2 and the return water temperature is ≤Y3, the first circulation pump is controlled to be closed, the drain valve is controlled to operate for drainage, and the water supply valve is controlled to be closed. When the auxiliary system detects that there is no water flow and displays the state X2, the drain valve is controlled to be closed;

[0016] 54) If the voltage of the auxiliary system drops to the drainage threshold value P2, the drainage valve is controlled to operate for drainage, and the water supply valve is controlled to close. When the auxiliary system detects that there is no water flow and displays the state X2, the drainage valve is controlled to close;

[0017] Condition 6) When the heat pump system needs to be temporarily shut down, the main control system detects the water flow status, ambient temperature and return water temperature, and executes according to condition 4 to detect the fault, and performs the following control at the same time:

[0018] ​61) If the ambient temperature ≥ H1 and the return water temperature ≥ Y1, then control the second circulation pump not to operate;

[0019] 62) If the ambient temperature ≤ H1 and Y3 < return water temperature ≤ Y2, then control the first circulation pump and the second circulation pump to operate;

[0020] 63) If the ambient temperature ≤ H1 and the return water temperature ≤ Y3, then control the first circulation pump and the second circulation pump to close, control the drain valve to operate for drainage, and at the same time control the makeup water valve to close. When the main control system detects no water flow and displays the status Z2, control the drain valve to close;

[0021] Condition 7): When the heat pump system needs to be shut down for a long time, the main control system prompts whether drainage is required. When it is confirmed to drain water, the main control system sends a drainage instruction to the auxiliary system. The auxiliary system controls the drain valve to operate for drainage, and at the same time controls the makeup water valve to close. When no water flow is detected and the status Z2 is displayed, control the drain valve to close; When it is not confirmed to drain water, the following control is carried out to achieve intelligent drainage:

[0022] 71) If the ambient temperature ≤ H1 and Y3 < return water temperature ≤ Y2, then control the first circulation pump to operate;

[0023] 72) If the ambient temperature ≤ H1 and the return water temperature ≤ Y3, then the main control system sends a drainage instruction to the auxiliary system. The auxiliary system controls the drain valve to operate for drainage, and at the same time controls the makeup water valve to close. When the main control system detects no water flow and displays the status Z2, control the drain valve to close.

[0024] Preferably, the charging logic is: when the voltage of the backup battery is lower than the minimum threshold P3, the main control system charges the backup battery; when the voltage of the backup battery is higher than the maximum threshold P1, the main control system stops charging the backup battery.

[0025] Preferably, H1 and H2 are ambient temperature reference values, Y1 is the maximum threshold of the return water temperature, Y2 is the minimum threshold of the return water temperature, Y3 is the limit threshold of the return water temperature, Y3 < Y2 < Y1, and P2 is the drainage threshold, P2 < P3 < P1.

[0026] When a power outage occurs in a low-temperature environment, the present invention can maintain the water circulation through the auxiliary system and turn on the drainage function when the return water temperature is too low or the backup battery power is insufficient, thereby preventing the heat pump system from being frozen.

[0027] The present invention can report a fault when the second circulation pump fails to work normally through communication between the main control system and the auxiliary system, and use the auxiliary system to start the first circulation pump to maintain water circulation, so as to avoid freezing of the heat pump system due to too low water temperature during maintenance and when the second circulation pump fails to work. At the same time, compared with conventional maintenance methods, the present invention does not need to drain water during maintenance, and the water circulation can be continuously turned on.

[0028] The present invention reduces maintenance costs, can directly determine the failures of a water flow switch, a circulation pump, and a sensor during the inspection process, and reduces maintenance time.

[0029] The present invention improves user experience, reduces losses, reduces sustained damage to the entire system, improves system reliability, facilitates problem troubleshooting, and reduces maintenance time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the heat pump system of the present invention;

[0031] Figure 2 It is the control principle diagram of the present invention;

[0032] Figure 3 It is the control principle diagram of the present invention. DETAILED DESCRIPTION

[0033] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0035] In addition, in the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise clearly specified.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0040] like Figure 1 The structure diagram of the heat pump system of the present invention is shown, which includes a main control system 1 and an auxiliary system 2. The circulating water circuit of the heat pump system is provided with a first circulating pump 3, a second circulating pump 4 and a drain valve 5 which are connected in series. The water replenishment water circuit of the heat pump system is provided with a water replenishment valve 6. The main control system 1 controls the second circulating pump 4 and the water replenishment valve 6. The auxiliary system 2 controls the first circulating pump 3, the drain valve 5 and the water replenishment valve 6. The auxiliary system 2 is provided with a backup battery. The main control system 1 and the auxiliary system 2 are connected by signals. For such a heat pump system, the present invention provides a control method for preventing the heat pump system from being frozen in a low temperature environment, such as Figure 2 , 3 As shown, the control method is as follows:

[0041] Condition 1) After the heat pump system is powered on, the main control system detects the ambient temperature and return water temperature.

[0042] Condition 2) After the heat pump system is powered on, the main control system detects the ambient temperature and return water temperature.

[0043] Condition 3) After the heat pump system is powered on, the main control system detects the ambient temperature and return water temperature.

[0044] Condition 4) During the operation of the heat pump system, the main control system monitors the ambient temperature and return water temperature in real time. When the ambient temperature is less than H1, the return water temperature is less than Y2, and there is no water flow and the display state is Z2, the following control is performed:

[0045] 41) The auxiliary system sends the water flow status data detected by the auxiliary system to the main control system. If there is water flow, the status X1 is displayed, and the main control system displays that the water flow switch of the main control system is faulty. If there is no water flow, the status X2 is displayed, and the operation of the first circulation pump is controlled by the auxiliary system;

[0046] 42) When the first circulation pump is turned on, if the main control system detects water flow, it displays state Z1, indicating that the second circulation pump is faulty, and the main control system reports the fault. When the fault is not eliminated, if the return water temperature is ≤ Y3, the first circulation pump is controlled to be turned off, and the drain valve is controlled to operate for drainage, and the water supply valve is controlled to be closed. When the main control system detects no water flow and displays state Z2, the drain valve is controlled to be closed;

[0047] Condition 5) During the operation of the heat pump system, if the main control system is powered off, the auxiliary system will detect the ambient temperature and return water temperature and perform the following control:

[0048] 51) If the ambient temperature is ≥H2 and the return water temperature is ≥Y1, the first circulation pump is controlled not to run;

[0049] 52) If the ambient temperature is ≤H2, Y3<return water temperature ≤Y2, the first circulation pump is controlled to operate;

[0050] ​​​53) If the ambient temperature is ≤H2 and the return water temperature is ≤Y3, the first circulation pump is controlled to be closed, the drain valve is controlled to operate for drainage, and the water supply valve is controlled to be closed. When the auxiliary system detects that there is no water flow and displays the state X2, the drain valve is controlled to be closed;

[0051] 54) If the voltage of the auxiliary system drops to the drainage threshold value P2, the drainage valve is controlled to operate for drainage, and the water supply valve is controlled to close. When the auxiliary system detects that there is no water flow and displays the state X2, the drainage valve is controlled to close;

[0052] Condition 6) When the heat pump system needs to be temporarily shut down, the main control system detects the water flow status, ambient temperature and return water temperature, and executes according to condition 4 to detect the fault, and performs the following control at the same time:

[0053] 61) If the ambient temperature is ≥H1 and the return water temperature is ≥Y1, the second circulation pump is controlled not to run;

[0054] 62) If the ambient temperature ≤ H1, Y3 < return water temperature ≤ Y2, the first circulation pump and the second circulation pump are controlled to operate;

[0055] 63) If the ambient temperature is ≤H1 and the return water temperature is ≤Y3, the first circulation pump and the second circulation pump are controlled to be closed, the drain valve is controlled to operate for drainage, and the water supply valve is controlled to be closed. When the main control system detects that there is no water flow and displays the state Z2, the drain valve is controlled to be closed;

[0056] Condition 7) When the heat pump system needs to be shut down for a long time, the main control system prompts whether drainage is required. When it is confirmed that drainage is required, the main control system sends a drainage command to the auxiliary system. The auxiliary system controls the drainage valve to operate for drainage and controls the water supply valve to close. When no water flow is detected and the display state Z2 is displayed, the drainage valve is controlled to close; when it is not confirmed that drainage is required, the following control is performed to realize intelligent drainage:

[0057] 71) If the ambient temperature is ≤H1, Y3<return water temperature ≤Y2, the first circulation pump is controlled to operate;

[0058] 72) If the ambient temperature is ≤H1 and the return water temperature is ≤Y3, the main control system sends a drainage command to the auxiliary system. The auxiliary system controls the drainage valve to drain water and controls the water supply valve to close. When the main control system detects that there is no water flow and displays status Z2, it controls the drainage valve to close.

[0059] When charging the backup battery, the present invention has the following charging logic: when the voltage of the backup battery is lower than the minimum threshold value P3, the main control system charges the backup battery; when the voltage of the backup battery is higher than the maximum threshold value P1, the main control system stops charging the backup battery.

[0060] In the present invention, H1 and H2 are ambient temperature reference values. When the ambient temperature is lower than the designed threshold value, the water circulation function or the drainage function needs to be turned on. When it is higher than the designed threshold value, the circulation water pump and the drainage function do not work. Y1 is the maximum threshold value of the return water temperature, Y2 is the minimum threshold value of the return water temperature, and Y3 is the limit threshold value of the return water temperature, where Y3 < Y2 < Y1. The so-called P2 is the drainage threshold value, and P2 < P3 < P1. The above data are preset at the time of factory shipment. At the same time, users can also modify them during the use process.

[0061] The drainage valve in the present invention is installed at the lowest position of the entire water circulation system, thus facilitating drainage.

[0062] Finally, it should be noted that the above-listed are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and there can be many variations. All variations that can be directly derived or联想到 by those of ordinary skill in the art from the disclosed content of the present invention should be considered as the protection scope of the present invention.

Claims

1. A control method for preventing a heat pump system from being frozen in a low temperature environment, characterized in that: The described heat pump system includes a main control system and an auxiliary system. A first circulation pump, a second circulation pump, and a drain valve are connected in series on the circulating water path of the heat pump system. A makeup water valve is provided on the makeup water path of the heat pump system. The main control system controls the second circulation pump and the makeup water valve, and the auxiliary system controls the first circulation pump, the drain valve, and the makeup water valve. The auxiliary system is equipped with a backup battery, and its control method is as follows: Condition 1): After the heat pump system is powered on, the main control system detects the ambient temperature and the return water temperature. When the ambient temperature <H1 and the return water temperature ≤Y2, it controls the second circulation pump to operate. If the main control system detects water flow in the system, it displays status Z1, indicating that the heat pump system is normal, and the main control system charges the backup battery of the auxiliary system according to the charging logic; Condition 2): After the heat pump system is powered on, the main control system detects the ambient temperature and the return water temperature. When the ambient temperature <H1 and the return water temperature ≤Y2, it controls the second circulation pump to operate. If the main control system detects no water flow in the system, it displays status Z2, indicating that the heat pump system is abnormal, reports a fault for prompt repair, the auxiliary system does not work, and the main control system charges the backup battery of the auxiliary system according to the charging logic; Condition 3): After the heat pump system is powered on, the main control system detects the ambient temperature and the return water temperature. When the ambient temperature <H1 and the return water temperature ≤Y2, it controls the second circulation pump to operate. If the main control system detects water flow in the system, it displays status Z1. At this time, turn on the electric heating until Y2 ≤ return water temperature <Y1, and then control the second circulation pump and the electric heating to turn off; Condition 4): During the operation of the heat pump system, the main control system monitors the ambient temperature and the return water temperature in real time. When the ambient temperature <H1, the return water temperature <Y2, and there is no water flow showing status Z2, the following controls are performed: 41) The auxiliary system sends the water flow status data detected by the auxiliary system to the main control system. If there is water flow, it displays status X1, and the main control system displays a main control system water flow switch fault. If there is no water flow, it displays status X2, and controls the first circulation pump to operate through the auxiliary system; 42) When the first circulation pump is turned on, if the main control system detects water flow, it displays status Z1, indicating a second circulation pump fault. The main control system reports the fault. When the fault has not been eliminated, if the return water temperature ≤Y3, then control the first circulation pump to turn off, control the drain valve to operate for drainage, and at the same time control the makeup water valve to close. When the main control system detects no water flow and displays status Z2, control the drain valve to close; Condition 5): During the operation of the heat pump system, if the main control system loses power, the auxiliary system detects the ambient temperature and the return water temperature and performs the following controls: 51) If the ambient temperature ≥H2 and the return water temperature ≥Y1, then control the first circulation pump not to operate; 52) If the ambient temperature ≤H2 and Y3 < return water temperature ≤Y2, then control the first circulation pump to operate; 53) If the ambient temperature ≤H2 and the return water temperature ≤Y3, then control the first circulation pump to close, control the drain valve to operate for drainage, and at the same time control the makeup water valve to close. When the auxiliary system detects no water flow and displays status X2, control the drain valve to close; 54) If the voltage of the auxiliary system drops to the drainage threshold P2, control the drainage valve to operate for drainage, and at the same time control the makeup water valve to close. When the auxiliary system detects no water flow and displays the status X2, control the drainage valve to close; Condition 6): When the heat pump system needs to be shut down temporarily, the main control system detects the water flow status, ambient temperature and return water temperature, and detects faults according to Condition 4, and at the same time performs the following controls: 61) If the ambient temperature ≥ H1 and the return water temperature ≥ Y1, control the second circulation pump not to operate; 62) If the ambient temperature ≤ H1 and Y3 < return water temperature ≤ Y2, control the first circulation pump and the second circulation pump to operate; 63) If the ambient temperature ≤ H1 and the return water temperature ≤ Y3, control the first circulation pump and the second circulation pump to close, control the drainage valve to operate for drainage, and at the same time control the makeup water valve to close. When the main control system detects no water flow and displays the status Z2, control the drainage valve to close; Condition 7): When the heat pump system needs to be shut down for a long time, the main control system prompts whether drainage is required. When it is confirmed that drainage is to be carried out, the main control system sends a drainage instruction to the auxiliary system. The auxiliary system controls the drainage valve to operate for drainage, and at the same time controls the makeup water valve to close. When no water flow is detected and the status Z2 is displayed, control the drainage valve to close; when it is not confirmed that drainage is to be carried out, the following controls are performed to achieve intelligent drainage: 71) If the ambient temperature ≤ H1 and Y3 < return water temperature ≤ Y2, control the first circulation pump to operate; 72) If the ambient temperature ≤ H1 and the return water temperature ≤ Y3, the main control system sends a drainage instruction to the auxiliary system. The auxiliary system controls the drainage valve to operate for drainage, and at the same time controls the makeup water valve to close. When the main control system detects no water flow and displays the status Z2, control the drainage valve to close.

2. A control method for preventing a heat pump system from being damaged by freezing in a low temperature environment according to claim 1, characterized in that: The charging logic is as follows: When the voltage of the backup battery is lower than the minimum threshold P3, the main control system charges the backup battery. When the voltage of the backup battery is higher than the maximum threshold P1, the main control system stops charging the backup battery.

3. A control method for preventing a heat pump system from being damaged by freezing in a low temperature environment according to claim 2, characterized in that: The H1 and H2 are ambient temperature reference values, Y1 is the maximum threshold of the return water temperature, Y2 is the minimum threshold of the return water temperature, Y3 is the limit threshold of the return water temperature, Y3 < Y2 < Y1, the P2 is the drainage threshold, and P2 < P3 < P1.

Images