CN116123732A - Defrosting control method of heat pump hot water heating system - Google Patents

Abstract

The invention relates to a defrosting control method of a heat pump hot water heating system, which comprises a heat pump hot water heating system, wherein the heat pump hot water heating system comprises a compressor, a high-pressure outlet of the compressor is communicated with a refrigerant side inlet of a plate heat exchanger through an electromagnetic four-way valve, a refrigerant side outlet of the plate heat exchanger is communicated with one end of an evaporator through an electronic expansion valve, the other end of the evaporator is communicated with a low-pressure inlet of the compressor through the electromagnetic four-way valve, a water outlet temperature sensor is arranged on a water side discharge pipe of the plate heat exchanger, a low-pressure inlet of the compressor is provided with an air return temperature sensor, and a high-pressure outlet pipe of the compressor is provided with an exhaust temperature sensor.

Description

A defrosting control method for a heat pump hot water heating system

technical field

The invention relates to a defrosting control method of a heat pump hot water heating system.

Background technique

The defrosting method of the existing heat pump hot water heating system usually adopts air-cooled defrosting, that is, it uses to detect whether the coil temperature reaches the set required temperature to determine whether to defrost. This defrosting control method, because it detects the coil temperature in the evaporating structure for defrosting, usually, an independent heat pump hot water heating system will only set a unique coil temperature on its evaporator Since this unique coil temperature can only detect the evaporation temperature of a certain branch in the evaporation structure, when using this evaporation temperature to judge whether there is a defrosting demand in the operation of the entire heat pump hot water heating system, it is very difficult System drift is prone to occur. Due to the bias flow of the system, the collected coil temperature will be too high or too low, which will lead to misjudgment, and finally cause frequent defrosting or no defrosting. Frequent defrosting or no defrosting will reduce the operating energy efficiency, stability and reliability of the heat pump hot water heating system, reduce the user experience of the heat pump hot water heating system, and even directly reduce the service life of the heat pump hot water heating system.

Chinese Patent Document No. CN 110671834 A disclosed a defrosting method for a heat pump system on January 10, 2020, including the following steps: S1, cumulative running time of unit compressor ≥ T1, and ambient temperature ≤ S1, and coil temperature ≤S2, the system enters defrosting operation, turns off the fan, activates the four-way valve, activates the bypass solenoid valve, and the unit defrosts; S2, when the defrosting running time ≤ T2 and the coil temperature ≤ S3, the exhaust temperature ≥ temperature S4 or system high pressure ≥ Y1 or compressor current ≥ rated current * 1.4, keep defrosting running, start fan running time after T3: 1) If defrosting running time ≥ T2 and coil temperature ≥ S3, stop defrosting running , close the four-way valve, close the bypass solenoid valve, and the unit performs normal heating; 2) If the defrosting running time ≤ T2 and the coil temperature ≤ S3, the exhaust temperature ≤ S4-30 and the high pressure ≤ Y1-0.6 and If the compressor current ≤ rated current, turn off the fan and continue defrosting until the defrosting running time ≥ T2 and coil temperature ≥ S3, stop defrosting, close the four-way valve, close the bypass solenoid valve, start the fan, and enter the normal state. Heating operation. The operating energy efficiency of this heat pump system is not ideal and needs to be improved.

Contents of the invention

The object of the present invention is to provide an accurate defrosting control method for a heat pump hot water heating system, so as to overcome the deficiencies in the prior art.

A defrosting control method for a heat pump hot water heating system designed according to this purpose, including a heat pump hot water heating system, is characterized in that the heat pump hot water heating system includes a compressor, and the high pressure outlet of the compressor passes through an electromagnetic four-way The valve is connected with the refrigerant side inlet of the plate heat exchanger, the refrigerant side outlet of the plate heat exchanger is connected with one end of the evaporator through the electronic expansion valve, and the other end of the evaporator is connected with the low pressure inlet of the compressor through the electromagnetic four-way valve There is an outlet water temperature sensor on the water side discharge pipe of the plate heat exchanger, a return air temperature sensor on the low-pressure inlet of the compressor, and an exhaust temperature sensor on the high-pressure outlet pipe of the compressor. The heat pump hot water heating system also Including the timer used to detect the cumulative running time of the system, the cumulative running time Rt is obtained through the timer, the return air temperature Ts is obtained through the return air temperature sensor, the outlet water temperature Tout is obtained through the outlet water temperature sensor, and the exhaust gas temperature is obtained through the exhaust temperature sensor Td, the central controller of the heat pump hot water heating system is electrically connected to the return air temperature sensor, timer, water temperature sensor and exhaust temperature sensor respectively, and the operation includes the following steps:

Step 1, power on the system and enter into step 2;

Step 2, normal operation, go to step 3;

Step 3, judge whether Ts≤M is established through the central controller, if it is established, enter step 4, otherwise enter step 2; where M is the return air temperature target value, and the value range of M is -10°C～-5 ℃;

Step 4, judge whether Rt>T is true through the central controller, and if it is true, go to step 5, otherwise go to step 2; wherein, T is the running time target value, and the value range of T is 45min～50min;

Step 5, judge whether Td-Tout≤N is established through the central controller, if it is established, enter step 6, otherwise enter step 2; where N is the defrosting temperature target value, and the value range of N is; 12℃～ 15°C;

Step six, enter the defrosting mode, go to step seven;

Step seven, judge whether the defrosting mode is over through the central controller, if it is established, go to step two, otherwise go to step six.

The present invention is not based on the detection of the ambient temperature, but on the detection of the return air temperature of the compressor, because by detecting the return air temperature, the frosting caused by the stall of the fan or the change of the evaporation environment can be detected. At the same time, By comparing the temperature difference between the exhaust gas temperature and the outlet water temperature with the preset value, it is possible to accurately determine whether the operating capacity of the heat pump hot water heating system has declined. When the evaporation capacity of the heat pump hot water heating system decreases, it will directly cause its heat pump Decrease in ability. The reason why the evaporation capacity of the heat pump hot water heating system decreases in a short time is mostly because the system is frosted during operation. When the capacity of the heat pump hot water heating system drops to a certain value, and the running time of the heat pump hot water heating system meets When the frost time is reached, the defrost mode can be used for defrosting.

In summary, the present invention has the characteristics of accurate control.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a control flow chart of the present invention.

In the figure: 1 is the evaporator, 2 is the ambient temperature sensor, 3 is the electromagnetic four-way valve, 4 is the return air temperature sensor, 5 is the exhaust pressure sensor, 6 is the exhaust temperature sensor, 7 is the plate heat exchanger, 8 10 is an electronic expansion valve, 11 is a return air pressure sensor, 12 is a compressor, 13 is an inlet water temperature sensor, 14 is a water pump, and 15 is an outlet water temperature sensor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Referring to Figures 1-2, a defrosting control method for a heat pump hot water heating system includes a heat pump hot water heating system, the heat pump hot water heating system includes a compressor 12, and the high pressure outlet of the compressor 12 is passed through an electromagnetic four The through valve 3 is connected with the inlet of the refrigerant side of the plate heat exchanger 7, the outlet of the refrigerant side of the plate heat exchanger 7 is connected with one end of the evaporator through the electronic expansion valve 10, and the other end of the evaporator is connected with the electromagnetic four-way valve 3. The low-pressure inlet of the compressor 12 is connected, the water-side discharge pipe of the plate heat exchanger 7 is provided with an outlet water temperature sensor 15, the low-pressure inlet of the compressor 12 is provided with a return air temperature sensor 4, and the high-pressure outlet pipe of the compressor 12 is provided with There is an exhaust temperature sensor 6, and the heat pump hot water heating system also includes a timer for detecting the cumulative running time of the system. The cumulative running time Rt is obtained through the timer, the return air temperature Ts is obtained through the return air temperature sensor 4, and the outlet water temperature sensor 15 obtains the outlet water temperature Tout, obtains the discharge temperature Td through the discharge temperature sensor 6, and the central controller of the heat pump hot water heating system is electrically connected to the return air temperature sensor 4, the timer, the water temperature sensor 15 and the discharge temperature sensor 6 respectively .

In this embodiment, the compressor is the power core of the heat pump hot water heating system. It can increase the temperature and pressure of the sucked low-temperature and low-pressure refrigerant vapor through compression, so that the refrigerant circulates continuously in the system and achieves The purpose of cooling and heating.

The plate heat exchanger plays the role of condensing high-temperature gas during heating. By releasing heat to the water side, it can heat the waterway medium. It plays the role of evaporating low-temperature liquid during cooling. By absorbing heat to the water side, It can reduce the temperature of the waterway medium.

The electromagnetic four-way reversing valve plays the role of reversing, which can change the direction of refrigerant circulation to achieve the purpose of cooling and heating.

The fin heat exchanger plays the role of evaporation when heating, and can reduce the temperature of the air by absorbing the heat in the air to achieve the purpose of cooling; it plays the role of condensing high-temperature gas during cooling, and releases heat to the air , can increase the air temperature to achieve the effect of air heating.

When the heat pump hot water heating system is working, operate according to the following method, which specifically includes the following steps.

Step 1: Power on the system and go to Step 2.

Step 2, normal operation, enter step 3; at this time, carry out normal operation according to the preset value or user setting value, and collect the corresponding temperature and pressure information through the central controller during operation.

Step 3, judge whether Ts≤M is established through the central controller, if it is established, enter step 4, otherwise enter step 2; where M is the return air temperature target value, and the value range of M is -10°C～-5 ℃; Since different types of heat pump hot water heating systems work in different environments, their performance is slightly different, so M can be selected according to the actual situation.

Step 4, judge whether Rt>T is true through the central controller, and if it is true, go to step 5, otherwise go to step 2; wherein, T is the running time target value, and the value range of T is 45min～50min;

In this embodiment, the accumulated running time Rt generally reaches 45 minutes to 50 minutes, and the detection of defrosting conditions can be performed to ensure the efficient operation of the heat pump hot water heating system.

Step 5, judge whether Td-Tout≤N is established through the central controller, if it is established, enter step 6, otherwise enter step 2; where N is the defrosting temperature target value, and the value range of N is; 12℃～ 15°C.

Example: Select the defrosting temperature target value N=12°C.

When the heat pump hot water heating system runs for a period of time, the exhaust temperature Td = 60°C, and the outlet water temperature Tout = 50°C. At this time, Td-Tout = 60°C-50°C = 10°C, so Td-Tout≤N Established, enter the follow-up defrosting mode.

If the discharge temperature Td = 60°C and the outlet water temperature Tout = 42°C, at this time, Td-Tout = 60°C-42°C = 18°C, so if Td-Tout≤N does not hold, return to step 2 and continue to run .

Step six, enter the defrost mode, go to step seven.

Step seven, judge whether the defrosting mode is over through the central controller, if it is established, go to step two, otherwise go to step six.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Orientation indicated by rear, left, right, vertical, horizontal, top, bottom, inside, outside, clockwise, counterclockwise, etc. The positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, Therefore, it should not be construed as limiting the present invention, and the terms "first" and "second" are only used for descriptive purposes, and should not be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (1)

1. The defrosting control method of the heat pump hot water heating system comprises the heat pump hot water heating system and is characterized in that the heat pump hot water heating system comprises a compressor (12), a high-pressure outlet of the compressor (12) is communicated with a refrigerant side inlet of a plate heat exchanger (7) through an electromagnetic four-way valve (3), a refrigerant side outlet of the plate heat exchanger (7) is communicated with one end of an evaporator through an electronic expansion valve (10), the other end of the evaporator is communicated with a low-pressure inlet of the compressor (12) through the electromagnetic four-way valve (3), a water outlet temperature sensor (15) is arranged on a water side discharge pipe of the plate heat exchanger (7), a return air temperature sensor (4) is arranged at a low-pressure inlet of the compressor (12), an exhaust air temperature sensor (6) is arranged at a high-pressure outlet pipe of the compressor (12), a timer for detecting accumulated running time of the system is further comprised, the return air temperature Ts is obtained through the return air temperature sensor (4), the water outlet temperature Tout is obtained through the return air temperature sensor (15), the temperature Td is obtained through the return air temperature sensor (4), and the temperature sensor (6) is electrically controlled by the exhaust air temperature sensor (6), and the temperature sensor (4) is respectively connected with the exhaust air temperature sensor (6), and the temperature sensor (4) is controlled by the timer:

step one, powering up a system, and entering a step two;

step two, normal operation, entering step three;

judging whether Ts is less than or equal to M or not through the central controller, if so, entering a fourth step, otherwise, entering a second step; wherein M is a return air temperature target value, and the value range of M is-10 ℃ to-5 ℃;

judging whether Rt > T is met or not through the central controller, entering a step five when the Rt > T is met, otherwise entering a step two; wherein T is a running time target value, and the value range of T is 45-50 min;

step five, judging whether Td-Tout is less than or equal to N or not through a central controller, if so, entering step six, otherwise, entering step two; wherein, N is a defrosting temperature target value, and the value range of N is; 12-15 ℃;

step six, entering a defrosting mode, and entering a step seven;

and step seven, judging whether the defrosting mode is finished or not through the central controller, entering the step two when the defrosting mode is established, and entering the step six if the defrosting mode is not established.

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