阅读说明：本技术 变频空气源热泵热水系统及运行控制方法 (Variable-frequency air source heat pump hot water system and operation control method ) 是由 徐言生 张正国 徐涛 吴治将 孙婉纯 李锡宇 李东洺 于 2021-09-14 设计创作，主要内容包括：本发明涉及一种变频空气源热泵热水系统及运行控制方法,特点是变频空气源热泵热水系统包括压缩机、储热换热器、旁路电子膨胀阀、制冷剂-水换热器、三通比例调节阀、循环水回水温度传感器、循环水出水温度传感器、主电子膨胀阀、室外环境温度传感器、室外机风机、室外机换热器、室外机换热器管温传感器、三通阀及气液分离器。其实现了热泵热水系统在化霜运行时仍按正向制热运行且能继续为用热端提供热量,供热稳定。(The invention relates to a variable-frequency air source heat pump hot water system and an operation control method, and is characterized in that the variable-frequency air source heat pump hot water system comprises a compressor, a heat storage heat exchanger, a bypass electronic expansion valve, a refrigerant-water heat exchanger, a three-way proportional control valve, a circulating water return water temperature sensor, a circulating water outlet water temperature sensor, a main electronic expansion valve, an outdoor environment temperature sensor, an outdoor unit fan, an outdoor unit heat exchanger pipe temperature sensor, a three-way valve and a gas-liquid separator. The heat pump hot water system still operates according to the forward heating during defrosting operation, can continuously provide heat for the hot end, and is stable in heat supply.)

1. A variable-frequency air source heat pump hot water system is characterized by comprising a compressor (1), a heat storage heat exchanger (2), a bypass electronic expansion valve (3), a refrigerant-water heat exchanger (4), a three-way proportional control valve (5), a circulating water return water temperature sensor (6), a circulating water outlet water temperature sensor (7), a main electronic expansion valve (8), an outdoor environment temperature sensor (9), an outdoor unit fan (10), an outdoor unit heat exchanger (11), an outdoor unit heat exchanger pipe temperature sensor (12), a three-way valve (13) and a gas-liquid separator (14);

an exhaust outlet of the compressor (1) is communicated with an inlet of a heat-releasing heat exchange tube in the heat storage heat exchanger (2), an outlet of the heat-releasing heat exchange tube in the heat storage heat exchanger (2) is communicated with an inlet of a refrigerant tube in the refrigerant-water heat exchanger (4), an outlet of the refrigerant tube in the refrigerant-water heat exchanger (4) is communicated with an inlet of a main electronic expansion valve (8), an outlet of the main electronic expansion valve (8) is communicated with an inlet of an outdoor unit heat exchanger (11), an outlet of the outdoor unit heat exchanger (11) is communicated with a tube A of a three-way valve (13), inlets of a gas-liquid separator (14) are respectively communicated with a tube B of the three-way valve (13) and a heat-absorbing outlet of the heat storage heat exchanger (2), an outlet of the gas-liquid separator (14) is communicated with a gas return port of the compressor (1), and a tube C of the three-way valve (13) is communicated with an inlet of a bypass electronic expansion valve (3), an outlet of the bypass electronic expansion valve (3) is communicated with an inlet of a heat absorption heat exchange tube in the heat storage heat exchanger (2), an E tube of the three-way proportional regulating valve (5) is communicated with a circulating water return pipe, an F tube of the three-way proportional regulating valve (5) is communicated with an inlet of a water pipeline of the refrigerant-water heat exchanger (4), and a G tube of the three-way proportional regulating valve (5) is respectively communicated with a circulating water outlet pipe and an outlet of the water pipeline of the refrigerant-water heat exchanger (4); the circulating water return temperature sensed by the circulating water return temperature sensor (6) is T1, the circulating water outlet temperature sensed by the circulating water outlet temperature sensor (7) is T2, the outdoor environment temperature sensed by the outdoor environment temperature sensor (9) is T3, and the outdoor heat exchanger tube temperature sensed by the outdoor heat exchanger tube temperature sensor (12) is T4.

2. The operation control method of the variable-frequency air source heat pump hot water system according to claim 1, characterized by comprising the following steps:

when the heat pump system normally heats, a pipe A of the three-way valve (13) is communicated with a pipe B, the compressor (1) exhausts air to a heat-releasing heat exchange pipe of the heat-storing heat exchanger (2), the heat-releasing heat exchange pipe exchanges heat with a heat-storing material in the heat-storing heat exchanger (2) through the heat-releasing heat exchange pipe to release part of heat, then the heat is exchanged with circulating water backwater in the refrigerant-water heat exchanger (4) to release heat and is condensed into refrigerant liquid, the liquid refrigerant is throttled by the main electronic expansion valve (8) and then enters the outdoor unit heat exchanger (11) to be evaporated and absorbs heat from the external environment, and the gaseous refrigerant flows into the pipe B of the three-way valve (13) from the pipe A of the three-way valve (13) to return to the gas-liquid separator (14) and then returns to the compressor (1);

(II) when the heat pump system operates in defrosting mode, the pipe A of the three-way valve (13) is communicated with the pipe C, the compressor (1) exhausts air, partial heat is released through the heat release heat exchange pipe of the heat storage heat exchanger (2), partial heat is released through the refrigerant-water heat exchanger (4) to circulating water, at the moment, the refrigerant becomes high-dryness saturated wet vapor, primary pressure reduction throttling is carried out through the main electronic expansion valve (8), the pressure and the temperature of the refrigerant are reduced, then the refrigerant enters the outdoor unit heat exchanger (11) to continuously release heat, all the high-dryness saturated wet vapor is condensed into refrigerant liquid, frost is absorbed by a frost layer on the surface of the outdoor unit heat exchanger (11), the refrigerant liquid flows into the bypass electronic expansion valve (3) from the pipe C of the three-way valve (13) from the pipe A of the three-way valve (13) to carry out secondary throttling, the throttled refrigerant enters the heat absorption heat exchange pipe of the heat storage heat exchanger (2), and absorbs heat from the heat storage material through the heat absorption heat exchange pipe to become refrigerant vapor, the gaseous refrigerant returns to the compressor (1) through the gas-liquid separator (14), and the heat pump system still continues to provide certain heat for the circulating water system in the defrosting process;

after defrosting is finished, the pipe A of the three-way valve (13) is communicated with the pipe B, the heat pump system is switched to normal heating operation, and the compressor (1) is not stopped in the defrosting-heating conversion process;

in the defrosting operation process of the heat pump system, the frequency of the compressor (1), the proportion of the three-way proportional regulating valve (5), the opening degree of the main electronic expansion valve (8) and the opening degree of the bypass electronic expansion valve (3) need to be controlled, and the control mode is as follows:

(a) the running frequency of the compressor (1) is increased to increase the heating capacity of the heat pump system, the defrosting running frequency range is 80-120 Hz, and if the running frequency of the compressor (1) before defrosting is greater than 100Hz, the original running frequency is kept;

(b) according to the defrosting operation frequency of the compressor (1) and the circulating water return temperature T1, the proportion of the three-way proportional control valve (5) and the preset numerical values of the opening degrees of the main electronic expansion valve (8) and the bypass electronic expansion valve (3) are obtained through an experimental method;

(c) the opening degree of the main electronic expansion valve (8) is secondarily adjusted according to the circulating water inlet and outlet temperature difference delta T = T2-T1; when delta T is more than or equal to 3 ℃ and less than or equal to 7 ℃, the opening degree of the main electronic expansion valve (8) is kept unchanged; when the delta T is less than 3 ℃, the opening degree of the main electronic expansion valve (8) is reduced to increase heat supply to the circulating water system, and when the delta T is more than 7 ℃, the opening degree of the main electronic expansion valve (8) is increased to increase defrosting heat supply to the outdoor heat exchanger (16).

3. The operation control method of the variable-frequency air-source heat pump hot water system according to claim 2, characterized in that the defrosting operation of the compressor (1) is particularly preferably performed at a frequency of 100 Hz.

Technical Field

The invention relates to a variable-frequency air source heat pump hot water system and an operation control method.

Background

The air source heat pump hot water system is used as a high-efficiency energy-saving hot water product and is widely applied to the fields of building heating, domestic hot water, industrial and agricultural production and the like. However, an important problem in the operation of the air source heat pump hot water system is that when the outdoor environment temperature is low, the surface of the outdoor heat exchanger frosts, and the performance of the heat pump system gradually decreases with the thickening of the frost layer, so the outdoor heat exchanger must be defrosted.

Currently, the most common defrosting method is the reverse operation of the heat pump system, i.e. the refrigeration operation, which requires heat from the original hot end. The main problem of the defrosting mode is that the defrosting process can not provide heat for the hot end, but needs to extract heat from the hot end. For a building heating system, the comfort of a human body can be influenced. In addition, after defrosting is finished, the compressor of the heat pump system needs to be stopped for a while to be switched into heating operation, and then the compressor is started again, so that the reliable operation of the heat pump system can be ensured. In the switching process of defrosting operation and heating operation, the operation stability of the heat pump system is influenced, and the performances of system energy consumption, heating capacity and the like are also influenced. The problem to be solved is firstly to solve the problem of heat source during defrosting and secondly to solve the problem of how to always perform forward heating operation of the heat pump system.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a variable-frequency air source heat pump hot water system and an operation control method thereof, so that the heat pump hot water system still operates according to forward heating during defrosting operation, can continuously provide heat for a hot end, and is stable in heat supply.

In order to achieve the purpose, the technical scheme of the variable-frequency air source heat pump hot water system is realized by the following steps that the variable-frequency air source heat pump hot water system is characterized by comprising a compressor, a heat storage heat exchanger, a bypass electronic expansion valve, a refrigerant-water heat exchanger, a three-way proportional control valve, a circulating water return water temperature sensor, a circulating water outlet water temperature sensor, a main electronic expansion valve, an outdoor environment temperature sensor, an outdoor unit fan, an outdoor unit heat exchanger pipe temperature sensor, a three-way valve and a gas-liquid separator;

the exhaust outlet of the compressor is communicated with the inlet of a heat-releasing heat exchange tube in the heat storage heat exchanger, the outlet of the heat-releasing heat exchange tube in the heat storage heat exchanger is communicated with the inlet of a refrigerant tube in the refrigerant-water heat exchanger, the outlet of the refrigerant tube in the refrigerant-water heat exchanger is communicated with the inlet of a main electronic expansion valve, the outlet of the main electronic expansion valve is communicated with the inlet of an outdoor heat exchanger, the outlet of the outdoor heat exchanger is communicated with a tube A of a three-way valve, the inlet of a gas-liquid separator is respectively communicated with a tube B of the three-way valve and the outlet of a heat-absorbing heat exchange tube in the heat storage heat exchanger, the outlet of the gas-liquid separator is communicated with the air return port of the compressor, a tube C of the three-way valve is communicated with the inlet of a bypass electronic expansion valve, the outlet of the bypass electronic expansion valve is communicated with the inlet of the heat-absorbing heat exchange tube in the heat storage heat exchanger, and a tube E of the three-way proportional regulating valve is communicated with a circulating water return pipe, the F pipe of the three-way proportional regulating valve is communicated with the water pipeline inlet of the refrigerant-water heat exchanger, and the G pipe of the three-way proportional regulating valve is respectively communicated with the circulating water outlet pipe and the water pipeline outlet of the refrigerant-water heat exchanger; the circulating water return temperature sensed by the circulating water return temperature sensor is T1, the circulating water outlet temperature sensed by the circulating water outlet temperature sensor is T2, the outdoor environment temperature sensed by the outdoor environment temperature sensor is T3, and the outdoor heat exchanger tube temperature sensed by the outdoor heat exchanger tube temperature sensor is T4.

In order to achieve the aim, the technical scheme of the operation control method of the variable-frequency air source heat pump hot water system is realized as follows, and the method is characterized by comprising the following steps:

when the heat pump system normally heats, the pipe A of the three-way valve is communicated with the pipe B, the compressor exhausts air to a heat-releasing heat exchange pipe of the heat-storing heat exchanger, the heat-releasing heat exchange pipe exchanges heat with a heat-storing material in the heat-storing heat exchanger to release part of heat, then the heat is exchanged with circulating water backwater in the refrigerant-water heat exchanger to release heat and condense the heat into refrigerant liquid, the liquid refrigerant enters an outdoor unit heat exchanger to be evaporated after being throttled by a main electronic expansion valve and absorbs heat from the external environment, and the gaseous refrigerant flows into the pipe B of the three-way valve from the pipe A of the three-way valve to return to a gas-liquid separator and then returns to the compressor;

(II) when the heat pump system operates in defrosting mode, the pipe A of the three-way valve is communicated with the pipe C, the compressor exhausts air, partial heat is released through the heat release heat exchange pipe of the heat storage heat exchanger, partial heat is released through the refrigerant-water heat exchanger to circulating water, at the moment, the refrigerant is changed into high-dryness saturated wet vapor, primary pressure reduction throttling is carried out through the main electronic expansion valve, the pressure and the temperature of the refrigerant are reduced, the refrigerant enters the outdoor unit heat exchanger to continuously release heat, the high-dryness saturated wet vapor is completely condensed into refrigerant liquid, frost is absorbed by a frost layer on the surface of the outdoor unit heat exchanger, the refrigerant liquid flows into the bypass electronic expansion valve from the pipe C of the three-way valve from the pipe A of the three-way valve, secondary throttling is carried out, the throttled refrigerant enters the heat absorption heat exchange pipe of the heat storage heat exchanger, heat is absorbed from the heat storage material through the heat absorption heat exchange pipe and is changed into refrigerant vapor, and the gaseous refrigerant returns to the compressor through the gas-liquid separator, in the defrosting process, the heat pump system still continues to provide certain heat for the circulating water system;

after defrosting is finished, the pipe A of the three-way valve is communicated with the pipe B, the heat pump system is switched to normal heating operation, and the compressor is not stopped in the defrosting-heating conversion process;

and (IV) the heat pump system defrosting operation process needs to control the frequency of the compressor, the proportion of the three-way proportional control valve, the opening of the main electronic expansion valve and the opening of the bypass electronic expansion valve, and the control mode is as follows:

(a) the running frequency of the compressor is increased to increase the heating capacity of the heat pump system, the defrosting running frequency range is 80-120 Hz, and if the running frequency of the compressor before defrosting is greater than 100Hz, the original running frequency is kept;

(b) obtaining the proportion of a three-way proportional control valve and preset numerical values of the openness of a main electronic expansion valve and a bypass electronic expansion valve through an experimental method according to the defrosting operation frequency of a compressor and the return water temperature T1 of circulating water;

(c) the opening degree of the main electronic expansion valve is adjusted for the second time according to the circulating water inlet and outlet temperature difference delta T = T2-T1; when delta T is more than or equal to 3 ℃ and less than or equal to 7 ℃, the opening degree of the main electronic expansion valve is kept unchanged; when the delta T is less than 3 ℃, the opening degree of the main electronic expansion valve is reduced to increase heat supply to the circulating water system, and when the delta T is more than 7 ℃, the opening degree of the main electronic expansion valve is increased to increase defrosting heat supply to the outdoor heat exchanger.

In the technical scheme, the defrosting operation of the compressor is particularly preferably performed at the frequency of 100 Hz.

Compared with the prior art, the invention has the following advantages:

(1) when in defrosting operation, partial heat can be continuously provided for the circulating water system, the fluctuation of the water temperature of the circulating water system is reduced, the defect caused by heat extraction from the circulating water system is avoided, and particularly when the heat pump system is used in a heating system, the discomfort caused by the reduction of the room temperature when the traditional heat pump system is defrosted is reduced;

(2) during defrosting operation, the refrigerant of the heat pump system still flows in the forward direction, and in the switching process of heating, defrosting and heating, the compressor is started without stopping, so that the energy consumption of the compressor is reduced, the operation condition of the compressor is improved, and the total heat production of the heat pump system is improved.

Drawings

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

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

As shown in fig. 1, the variable-frequency air source heat pump hot water system includes a compressor 1, a heat storage heat exchanger 2, a bypass electronic expansion valve 3, a refrigerant-water heat exchanger 4, a three-way proportional control valve 5, a circulating water return temperature sensor 6, a circulating water outlet temperature sensor 7, a main electronic expansion valve 8, an outdoor environment temperature sensor 9, an outdoor unit fan 10, an outdoor unit heat exchanger 11, an outdoor unit heat exchanger tube temperature sensor 12, a three-way valve 13, and a gas-liquid separator 14.

An exhaust outlet of the compressor 1 is communicated with an inlet of a heat-releasing heat exchange tube in the heat storage heat exchanger 2, an outlet of the heat-releasing heat exchange tube in the heat storage heat exchanger 2 is communicated with an inlet of a refrigerant tube in the refrigerant-water heat exchanger 4, an outlet of the refrigerant tube in the refrigerant-water heat exchanger 4 is communicated with an inlet of a main electronic expansion valve 8, an outlet of the main electronic expansion valve 8 is communicated with an inlet of an outdoor heat exchanger 11, an outlet of the outdoor heat exchanger 11 is communicated with a tube A of a three-way valve 13, an inlet of a gas-liquid separator 14 is respectively communicated with a tube B of the three-way valve 13 and an outlet of a heat-absorbing heat exchange tube in the heat storage heat exchanger 2, an outlet of the gas-liquid separator 14 is communicated with an air return port of the compressor 1, a tube C of the three-way valve 13 is communicated with an inlet of a bypass electronic expansion valve 3, and an outlet of the bypass electronic expansion valve 3 is communicated with an inlet of the heat-absorbing heat exchange tube in the heat storage heat exchanger 2, the E pipe of the three-way proportional control valve 5 is communicated with a circulating water return pipe, the F pipe of the three-way proportional control valve 5 is communicated with the water pipeline inlet of the refrigerant-water heat exchanger 4, and the G pipe of the three-way proportional control valve 5 is respectively communicated with a circulating water outlet pipe and the water pipeline outlet of the refrigerant-water heat exchanger 4.

The circulating water return temperature sensed by the circulating water return temperature sensor 6 is T1, the circulating water outlet temperature sensed by the circulating water outlet temperature sensor 7 is T2, the outdoor environment temperature sensed by the outdoor environment temperature sensor 9 is T3, and the outdoor heat exchanger tube temperature sensed by the outdoor heat exchanger tube temperature sensor 12 is T4.

In this embodiment, the operation control flow of the variable-frequency air source heat pump hot water system is as follows:

when the heat pump system normally heats, the pipe A of the three-way valve 13 is communicated with the pipe B, at the moment, the pipe A of the three-way valve 13 is not communicated with the pipe C, the compressor 1 exhausts air to the heat-releasing heat exchange pipe of the heat-storing heat exchanger 2, the heat-releasing heat exchange pipe exchanges heat with the heat-storing material in the heat-storing heat exchanger 2 to release part of heat, then the heat is exchanged with circulating water backwater in the refrigerant-water heat exchanger 4 to release heat and be condensed into refrigerant liquid, the liquid refrigerant enters the outdoor unit heat exchanger 11 to be evaporated and absorbs heat from the external environment after being throttled by the main electronic expansion valve 8, and the gaseous refrigerant returns to the gas-liquid separator 14 through the pipe A of the three-way valve 13 to the pipe B and then returns to the compressor 1;

(II) when the heat pump system operates in defrosting mode, the pipe A of the three-way valve 13 is communicated with the pipe C, at the moment, the pipe A of the three-way valve 13 is not communicated with the pipe B, the exhaust gas of the compressor 1 discharges part of heat through the heat-releasing heat exchange pipe of the heat-storage heat exchanger 2, and then the part of heat is discharged to circulating water through the refrigerant-water heat exchanger 4, at the moment, the refrigerant becomes high-dryness saturated wet vapor, the refrigerant is subjected to primary pressure reduction and throttling through the main electronic expansion valve 8, the pressure and the temperature of the refrigerant are reduced, then the refrigerant enters the outdoor unit heat exchanger 11 to continuously release heat, the outdoor unit fan 10 does not operate in the defrosting process, all the high-dryness saturated wet vapor is condensed into refrigerant liquid, frost on the surface of the outdoor unit heat exchanger 11 absorbs heat and is defrosted, the refrigerant liquid enters the bypass electronic expansion valve 3 through the pipe A to the pipe C of the three-way valve 13 to perform secondary throttling, the refrigerant enters the heat-absorbing heat exchange pipe of the heat-storage heat exchanger 2 after throttling, the heat is absorbed from the heat storage material through the heat absorption heat exchange pipe and changed into refrigerant vapor, and the gaseous refrigerant returns to the compressor 1 through the gas-liquid separator 14; in the defrosting process, the heat pump system still continues to provide certain heat for the circulating water system;

after defrosting is finished, the pipe A of the three-way valve 13 is communicated with the pipe B, at the moment, the pipe A of the three-way valve 13 is not communicated with the pipe C, and the heat pump system is switched to normal heating operation; the compressor 1 is not stopped in the defrosting-heating conversion process;

in the defrosting operation process of the heat pump system, the frequency of the compressor 1, the proportion of the three-way proportional regulating valve 5, the opening degree of the main electronic expansion valve 8 and the opening degree of the bypass electronic expansion valve 3 need to be controlled, and the following control mode is adopted:

(1) the running frequency of the compressor 1 is increased to increase the heating capacity of the heat pump system, the defrosting running frequency range is 80-120 Hz, the defrosting running frequency can be 80Hz, 90Hz, 100Hz, 110Hz and 120 Hz, particularly preferably 100Hz, and if the running frequency of the compressor 1 before defrosting is greater than 100Hz, the original running frequency is kept;

(2) obtaining the proportion of the three-way proportional control valve 5 and preset numerical values of the opening degrees of the main electronic expansion valve 8 and the bypass electronic expansion valve 3 through an experimental method according to the defrosting operation frequency of the compressor 1 and the circulating water return water temperature T1;

(3) the opening degree of the main electronic expansion valve 8 is secondarily adjusted according to the hot water inlet and outlet temperature difference delta T = T2-T1; when delta T is more than or equal to 3 ℃ and less than or equal to 7 ℃, the opening degree of the main electronic expansion valve 8 is kept unchanged; when the delta T is less than 3 ℃, the opening degree of the main electronic expansion valve 8 is reduced to increase heat supply to the circulating water system, and when the delta T is more than 7 ℃, the opening degree of the main electronic expansion valve 8 is increased to increase defrosting heat supply to the outdoor heat exchanger 16.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.