CN115200180A - High-stability variable-frequency heated water heater control system - Google Patents
High-stability variable-frequency heated water heater control system Download PDFInfo
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- CN115200180A CN115200180A CN202210748391.XA CN202210748391A CN115200180A CN 115200180 A CN115200180 A CN 115200180A CN 202210748391 A CN202210748391 A CN 202210748391A CN 115200180 A CN115200180 A CN 115200180A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
- F24F11/63—Electronic processing
- F24F11/64—Electronic processing using pre-stored data
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F11/41—Defrosting; Preventing freezing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
- F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
- F24F11/85—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using variable-flow pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/86—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling compressors within refrigeration or heat pump circuits
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F5/00—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater
- F24F5/0007—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater cooling apparatus specially adapted for use in air-conditioning
- F24F5/001—Compression cycle type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2221/00—Details or features not otherwise provided for
- F24F2221/34—Heater, e.g. gas burner, electric air heater
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
Abstract
The invention discloses a high-stability variable-frequency heated water heater control system, which relates to the technical field of air conditioners, and comprises a main control unit, an information acquisition component and an execution unit; the control system of the variable-frequency heated water heater unit acquires signals such as temperature, pressure and switching value of the unit through the information acquisition element and outputs control signals after logical operation processing, and the control system controls the operation of the CO2 dual-rotor variable-frequency compressor, the electronic expansion valve, the defrosting electromagnetic valve, the compressor oil temperature heating band, the intermediate pressure bypass electromagnetic valve, the gas-liquid separator electric heating band, the variable-frequency water pump and the variable-frequency fan. The invention relates to a high-stability variable-frequency heated water heater control system, which solves the problem that the pressure of an intermediate cavity is higher than the exhaust pressure in the operation process of a variable-frequency heated water heater unit, ensures the reliable operation of the unit, provides hot water up to 95 ℃ and can meet the requirements of users.
Description
Technical Field
The invention relates to the technical field of air conditioning equipment, in particular to a high-stability control system of a variable-frequency heated water heater.
Background
With the increasing emphasis on environmental protection, clean and environment-friendly refrigerants are increasingly popular. The ODP =0 and GWP =1 of CO2 has excellent thermal property, easy preparation, no toxicity, no decomposition, no flammability and no explosion, and the advantages of the characteristics make CO2 very suitable for being used as a refrigerant in an air conditioning system. However, the critical pressure of CO2 is quite high and its critical point temperature is low, so its condensation heat dissipation is in the supercritical region, and therefore the working pressure of the CO2 air conditioning system needs to be higher than its critical pressure. Therefore, the CO2 double-rotor compressor is selected in the scheme so as to achieve the purpose that the exhaust pressure is higher than the critical pressure of CO 2. In actual tests, the phenomenon that the pressure of a middle cavity of a CO2 dual-rotor compressor is higher than the exhaust pressure occurs in the running process of a unit, the heating capacity of the unit is reduced, and the service life of the compressor is also shortened.
Disclosure of Invention
The invention provides a high-stability variable-frequency heated water heater control system, which aims to solve the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme:
a high-stability control system of a variable-frequency heated water heater unit comprises a main control unit, an information acquisition component and an execution unit;
the information acquisition component comprises a temperature sensor, a pressure sensor, a high-pressure switch, a high liquid level switch, a medium liquid level switch and a low liquid level switch;
the execution unit comprises a CO2 dual-rotor variable frequency compressor, a variable frequency water pump, an electronic expansion valve, a water inlet three-way valve, a defrosting bypass valve, an intermediate pressure bypass electromagnetic valve, an EC direct current fan, a water tank electric heater, a compressor oil temperature electric heater and a gas-liquid separator electric heater;
the control system of the variable-frequency heated water heater unit acquires signals of the unit such as temperature, pressure and switching value through the information acquisition element and outputs control signals after logical operation processing, and controls the operation of the CO2 dual-rotor variable-frequency compressor, the electronic expansion valve, the defrosting electromagnetic valve, the compressor oil temperature heating band, the intermediate pressure bypass electromagnetic valve, the gas-liquid separator electric heating band, the variable-frequency water pump and the variable-frequency fan.
Preferably, the control of the CO2 dual-rotor inverter compressor specifically comprises:
the pressure of an exhaust gas-intermediate cavity is required to be ensured to be larger than S1Bar in the running process of the CO2 double-rotor variable frequency compressor, and tests show that when the frequency of the compressor changes rapidly and the electronic expansion valve acts rapidly, the phenomenon that the pressure of the intermediate cavity is larger than the pressure of the exhaust gas is easily generated, aiming at the problem, the frequency increasing and decreasing speed of the compressor is controlled, and when the difference between the water outlet temperature of the water heater and a set value is not large, the frequency of the compressor is increased or decreased by nHz within T1 second; when the temperature of the water discharged from the water heater is greatly different from a set value, the rotating speed of the compressor is increased or decreased at nHz within T2 seconds, and at the moment, the difference S between the exhaust pressure and the pressure of the intermediate cavity is detected, if S is greater than S1, the nHz is increased or decreased within T2 seconds, and if S is less than S1, the nHz is increased or decreased within T1 seconds; the compressor is started and stopped according to manual start-stop signals or according to liquid level switch control in the standby process, the compressor is stopped when the high liquid level switch is closed, and the compressor is started when the middle liquid level switch is disconnected.
Preferably, the control of the variable-frequency water pump is specifically as follows:
in order to ensure that the outlet water temperature of the water heater can quickly reach the set temperature, the control of the variable-frequency water pump is increased because the frequency increasing and decreasing rate of the compressor is limited; when the water heater is started, the frequency raising speed is low after the compressor is started, so that the outlet water temperature can quickly reach the set temperature, the output of the variable frequency water pump is reduced, and the water flow is reduced to achieve the purpose of high outlet water temperature; when the outlet water temperature of the unit rises along with the rise of the frequency of the compressor, the output of the variable frequency water pump is increased, so that the higher outlet water temperature is kept and the water tank is filled with hot water more quickly.
Preferably, the control of heating and defrosting specifically includes:
the defrosting condition of the unit is that the ambient temperature is lower than a set value, the ambient temperature-fin evaporator temperature (outer coil temperature) is higher than the set value, the compressor running time is greater than the minimum compressor running time, the defrosting condition is quit, the fin evaporator temperature (outer coil temperature) is higher than the set value, the CO2 water heater adopts hot gas bypass defrosting, and the flow direction of a refrigerant during normal heating is as follows: compressor-air cooler-heat regenerator-electronic expansion valve-fin evaporator-heat regenerator-gas-liquid separator-compressor; when the defrosting operation is performed, after the water heater reaches the defrosting condition, the defrosting bypass electromagnetic valve is opened, and the electronic expansion valve is closed (the defrosting bypass electromagnetic valve and the electronic expansion valve act simultaneously, and the compressor is not stopped, so that the probability of generating an air hammer of a refrigerant circulating system can be reduced, and the risk of pipeline vibration cracking is reduced); the flow direction of the refrigerant at this moment is compression-defrosting bypass electromagnetic valve-fin evaporator-heat regenerator-gas-liquid separator-compressor; turning off the variable frequency water pump, turning off the EC direct current fan, and defrosting the compressor without stopping; the purpose of the series of actions is to ensure that heat generated during heating operation of the compressor generates heat exchange in the evaporator as much as possible, so that accumulated frost on the evaporator is melted and heat waste caused by heat exchange with water and air in the air in a water system is avoided; in the defrosting process, the compressor enters a defrosting rotating speed (low-rotating-speed operation), which aims to reduce the flow rate of CO2 in a refrigerant system and increase the heat exchange efficiency of the CO2 and accumulated frost, so that the defrosting is performed as soon as possible; and the gas-liquid separator is provided with gas-liquid separator electric heating, and when defrosting control is carried out, the gas-liquid separator electric heating is started to provide extra heat for defrosting of the hot water unit.
Preferably, the control of the water inlet three-way valve specifically comprises:
when hot water in the water tank is not used for a long time, the main control unit opens the water inlet three-way valve after detecting that the temperature of the hot water in the water tank is reduced, so that a circulating water path is formed among the water tank, the variable-frequency water pump and the water heater, and then the main control unit starts the water heater unit to heat and raise the temperature of the water in the water tank;
when the environmental temperature is low in winter, particularly the temperature of minus ten or twenty and several degrees in northern areas, the unit needs to be protected from freezing, when the detected environmental temperature is lower than 0 ℃, any one of the temperature of a water tank or the temperature of outlet water is lower than a set value, the unit enters a freezing prevention mode, a water inlet three-way valve is closed, a loop is formed among the water tank, a variable-frequency water pump and a water heater, then a main control unit starts the water pump by a water pump signal, a compressor is started after the water pump runs to heat, the temperature of water in the water tank and water in a pipeline is raised, and when the water temperature (the temperature of the water tank or the temperature of the water in the water tank) is higher than the set value for freezing prevention, the unit is closed, the water pump is closed, and the water inlet three-way valve is closed.
Preferably, the control of the electronic expansion valve is specifically:
the electronic expansion valve is adjusted by keeping the temperature difference between the outlet temperature and the inlet temperature of the air cooler, so that the stable and efficient operation of the water heater is realized, and the exhaust temperature, the exhaust pressure and the like can be within normal ranges;
the control system defines: air cooler outlet temperature-inlet water temperature = approach temperature T;
the opening degree of the electronic expansion valve is adjusted by comparing the set approximate temperature target value TS with the difference T1 between the actual air cooler outlet temperature and the inlet water temperature and by PID calculation.
Preferably, the control of the electrical heating of the gas-liquid separator specifically comprises:
the electric heating of the gas-liquid separator is used for preventing the heat stored by the compressor from being insufficient to fully remove frost accumulated on the evaporator during defrosting; when defrosting control is carried out, the main control unit can start the gas-liquid separator to be electrically heated, so that the heat during defrosting is increased, and frost accumulated on the evaporator can be thoroughly removed.
Preferably, the control of the intermediate-pressure bypass solenoid valve specifically comprises:
the CO2 double-rotor variable frequency compressor needs to be ensured in the operation process: the exhaust pressure-intermediate cavity pressure is greater than S1Bar;
the function of the intermediate pressure bypass solenoid valve is as follows: when the exhaust pressure and the middle cavity pressure are less than or equal to S1Bar, the main control unit outputs a signal, and opens a middle pressure bypass electromagnetic valve to enable the middle cavity pressure to be communicated with a CO2 dual-rotor variable frequency compressor return gas pipeline through a pipeline, so that the middle cavity pressure is reduced, the pressure difference (the difference between the exhaust pressure and the middle cavity pressure is greater than S1) is reestablished, the middle pressure bypass electromagnetic valve is closed after running for a period of time t, and the difference between the pressure difference and the pressure difference can be still ensured to be greater than S1 after the electromagnetic valve is closed.
Preferably, the control of the electrical heating of the gas-liquid separator specifically comprises:
the electric heating of the gas-liquid separator is used for providing additional heat for defrosting by removing the heat of the compressor when the unit is defrosted;
the control method comprises the following steps: when the unit normally operates, the gas-liquid separator is not started by electric heating, when the unit enters a defrosting mode, the main control unit outputs a signal to start the gas-liquid separator to be electrically heated, and when the unit exits the defrosting mode, the main control unit outputs a signal to stop the electric heating of the gas-liquid separator.
Compared with the prior art, the invention has the beneficial effects that:
the invention relates to a high-stability variable-frequency heated water heater control system, which solves the problem that the pressure of an intermediate cavity is higher than the exhaust pressure in the operation process of a variable-frequency heated water heater unit, ensures the reliable operation of the unit, provides hot water up to 95 ℃ and can meet the requirements of users.
Drawings
FIG. 1 is a flow chart of the working principle of the present invention;
fig. 2 is a flow chart of the working principle of the main control unit in the invention.
In the figure:
1. a compressor; 2. an air cooler; 3. a heat regenerator; 4. an electronic expansion valve; 5. a finned evaporator; 6. a gas-liquid separator; 7. a defrosting bypass solenoid valve; 8. frequency conversion water pump.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
Referring to fig. 1-2, the present invention provides a technical solution:
a high-stability control system of a variable-frequency heated water heater unit comprises a main control unit, an information acquisition component and an execution unit;
the information acquisition components comprise temperature sensors, pressure sensors, high-pressure switches, high liquid level switches, medium liquid level switches and low liquid level switches;
the execution unit comprises a CO2 dual-rotor variable frequency compressor, a variable frequency water pump, an electronic expansion valve, a water inlet three-way valve, a defrosting bypass valve, an intermediate pressure bypass electromagnetic valve, an EC direct current fan, a water tank electric heater, a compressor oil temperature electric heater and a gas-liquid separator electric heater;
the control system of the variable-frequency heated water heater unit acquires signals of the unit such as temperature, pressure and switching value through the information acquisition element and outputs control signals after logical operation processing, and controls the operation of the CO2 dual-rotor variable-frequency compressor, the electronic expansion valve, the defrosting electromagnetic valve, the compressor oil temperature heating band, the intermediate pressure bypass electromagnetic valve, the gas-liquid separator electric heating band, the variable-frequency water pump and the variable-frequency fan.
The CO2 double-rotor variable frequency compressor is specifically controlled as follows:
the CO2 double-rotor frequency conversion compressor needs to ensure that the pressure of an exhaust pressure-intermediate cavity is more than S1Bar in the running process, and tests show that when the frequency of the compressor changes rapidly and the electronic expansion valve acts rapidly, the phenomenon that the pressure of the intermediate cavity is greater than the pressure of the exhaust pressure is easily generated, aiming at the problem, by controlling the frequency increasing and decreasing speed of the compressor, when the difference between the water outlet temperature of the water heater and a set value is not large, the frequency of the compressor is increased or decreased by nHz within T1 second; when the temperature of the water discharged from the water heater is greatly different from a set value, the rotating speed of the compressor is increased or decreased at nHz within T2 seconds, and at the moment, the difference S between the exhaust pressure and the pressure of the intermediate cavity is detected, if S is greater than S1, the nHz is increased or decreased within T2 seconds, and if S is less than S1, the nHz is increased or decreased within T1 seconds; the compressor is started and stopped according to manual start-stop signals or according to liquid level switch control in the standby process, the compressor is stopped when the high liquid level switch is closed, and the compressor is started when the middle liquid level switch is disconnected.
The control of the variable-frequency water pump is specifically as follows:
in order to ensure that the outlet water temperature of the water heater can reach the set temperature quickly, the control of the variable frequency water pump is increased because the frequency increasing and decreasing speed of the compressor is limited; when the water heater is started, because the frequency raising speed is lower after the compressor is started, in order to enable the outlet water temperature to quickly reach the set temperature, the output of the variable frequency water pump is reduced, and the water flow is reduced so as to achieve the purpose of high outlet water temperature; when the outlet water temperature of the unit rises along with the rise of the frequency of the compressor, the output of the variable frequency water pump is increased, so that the outlet water temperature is kept higher, and the water tank is filled with hot water quickly.
The control of heating and defrosting is specifically as follows:
the unit enters the defrosting condition that the ambient temperature is lower than a set value, the ambient temperature-the temperature of the finned evaporator (the temperature of the outer coil) is higher than the set value, the running time of the compressor is larger than the minimum running time of the compressor, the unit exits the defrosting condition that the temperature of the finned evaporator (the temperature of the outer coil) is higher than the set value, the CO2 water heater adopts hot gas bypass defrosting, and the flow direction of a refrigerant is as follows during normal heating: the system comprises a compressor 1, an air cooler 2, a heat regenerator 3, an electronic expansion valve 4, a fin evaporator 5, a heat regenerator 6, a gas-liquid separator 7 and a compressor 8; when the defrosting operation is performed, after the water heater reaches the defrosting condition, the defrosting bypass electromagnetic valve is opened, and the electronic expansion valve is closed (the defrosting bypass electromagnetic valve and the electronic expansion valve act simultaneously, and the compressor is not stopped, so that the probability of generating an air hammer of a refrigerant circulating system can be reduced, and the risk of pipeline vibration cracking is reduced); the flow direction of the refrigerant at this time is compressor 1-defrosting bypass solenoid valve 7-fin evaporator 5-heat regenerator 3-gas-liquid separator 6-compressor 1; the variable frequency water pump is closed, the EC direct current fan is closed, and the compressor defrosts without stopping; the purpose of the series of actions is to ensure that heat generated during heating operation of the compressor generates heat exchange in the evaporator as much as possible, so that accumulated frost on the evaporator is melted and heat waste caused by heat exchange with water and air in the air in a water system is avoided; in the defrosting process, the compressor enters a defrosting rotating speed (low-rotating-speed operation), which aims to reduce the flow rate of CO2 in a refrigerant system and increase the heat exchange efficiency of the CO2 and accumulated frost, so that the defrosting is performed as soon as possible; and install vapour and liquid separator electrical heating on vapour and liquid separator, vapour and liquid separator electrical heating starts when getting into defrosting control, provides extra heat for the defrosting of hot water unit.
The control of the water inlet three-way valve is as follows:
when hot water in the water tank is not used for a long time, the main control unit opens the water inlet three-way valve after detecting that the temperature of the hot water in the water tank is reduced, so that a circulating water path is formed among the water tank, the variable-frequency water pump and the water heater, and then the main control unit starts the water heater unit to heat and raise the temperature of the water in the water tank;
when the environmental temperature is low in winter, particularly in the minus ten and several dozens and twenty degrees in northern areas, the unit needs to be protected against freezing, when the detected environmental temperature is lower than 0 ℃, any one of the temperature of a water tank or the temperature of outlet water is lower than a set value, an anti-freezing mode is entered, a water inlet three-way valve is closed, a loop is formed among the water tank, a variable frequency water pump and a water heater, then a main control unit starts the water pump by a water pump signal, a compressor is started after the water pump is operated, heating is carried out, the temperature of water in the water tank and water in a pipeline is raised, and when the water temperature (the temperature of the water tank or the temperature of the water in the water tank) is higher than the anti-freezing set value, the unit is closed, the water pump is closed, and the water inlet three-way valve is closed.
The control of the electronic expansion valve specifically comprises the following steps:
the electronic expansion valve is adjusted by keeping the temperature difference between the outlet temperature and the inlet temperature of the air cooler, so that the water heater can stably and efficiently operate, and the exhaust temperature, the exhaust pressure and the like can be within a normal range;
the control system defines: air cooler outlet temperature-inlet water temperature = approach temperature T;
the opening degree of the electronic expansion valve is adjusted by comparing the set approximate temperature target value TS with the difference T1 between the actual air cooler outlet temperature and the inlet water temperature and by PID calculation.
The control of the electric heating of the gas-liquid separator specifically comprises the following steps:
the electric heating of the gas-liquid separator is used for preventing the heat stored by the compressor from being insufficient to fully remove frost accumulated on the evaporator during defrosting; when defrosting control is performed, the main control unit starts the gas-liquid separator to be electrically heated, and heat during defrosting is increased, so that accumulated frost on the evaporator can be thoroughly removed.
The control of the intermediate pressure bypass electromagnetic valve specifically comprises the following steps:
the CO2 double-rotor variable frequency compressor needs to be ensured in the operation process: the exhaust pressure-intermediate cavity pressure is greater than S1Bar;
the function of the intermediate pressure bypass solenoid valve is as follows: when the exhaust pressure and the intermediate cavity pressure are less than or equal to S1Bar, the main control unit outputs a signal, opens the intermediate pressure bypass electromagnetic valve, enables the intermediate cavity pressure to be communicated with a CO2 double-rotor frequency conversion compressor return air pipeline through a pipeline, achieves the purpose of reducing the intermediate cavity pressure, reestablishes the pressure difference (the difference between the exhaust pressure and the intermediate cavity pressure is larger than S1), closes the intermediate pressure bypass electromagnetic valve after the operation for a period of time t, and can still ensure that the difference between the pressure difference and the pressure difference is larger than S1 after the electromagnetic valve is closed.
The control of the electric heating of the gas-liquid separator specifically comprises the following steps:
the electric heating of the gas-liquid separator is used for providing additional heat for defrosting except the heat of the compressor when the unit is defrosted;
the control method comprises the following steps: when the unit normally operates, the gas-liquid separator is not started by electric heating, when the unit enters a defrosting mode, the main control unit outputs a signal to start the gas-liquid separator to be electrically heated, and when the unit exits the defrosting mode, the main control unit outputs a signal to stop the electric heating of the gas-liquid separator.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Claims (9)
1. The utility model provides a high frequency conversion heated type water heater control system of stability which characterized in that: the variable-frequency heated water heater unit comprises a main control unit, an information acquisition component and an execution unit;
the information acquisition components comprise temperature sensors, pressure sensors, high-pressure switches, high liquid level switches, medium liquid level switches and low liquid level switches;
the execution unit comprises a CO2 dual-rotor variable frequency compressor, a variable frequency water pump, an electronic expansion valve, a water inlet three-way valve, a defrosting bypass valve, an intermediate pressure bypass electromagnetic valve, an EC direct current fan, a water tank electric heater, a compressor oil temperature electric heater and a gas-liquid separator electric heater;
the control system of the variable-frequency heated water heater unit acquires signals of temperature, pressure, switching value and the like of the unit through the information acquisition component, outputs control signals after logical operation processing, and controls the operation of the CO2 dual-rotor variable-frequency compressor, the electronic expansion valve, the defrosting electromagnetic valve, the compressor oil temperature heating band, the intermediate pressure bypass electromagnetic valve, the gas-liquid separator electric heating band, the variable-frequency water pump and the variable-frequency fan.
2. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the CO2 double-rotor variable frequency compressor is specifically controlled as follows:
the pressure of an exhaust gas-intermediate cavity is required to be ensured to be larger than S1Bar in the running process of the CO2 double-rotor variable frequency compressor, and tests show that when the frequency of the compressor changes rapidly and the electronic expansion valve acts rapidly, the phenomenon that the pressure of the intermediate cavity is larger than the pressure of the exhaust gas is easily generated, aiming at the problem, the frequency increasing and decreasing speed of the compressor is controlled, and when the difference between the water outlet temperature of the water heater and a set value is not large, the frequency of the compressor is increased or decreased by nHz within T1 second; when the temperature of the water discharged from the water heater is greatly different from a set value, the rotating speed of the compressor is increased or decreased at nHz within T2 seconds, and at the moment, the difference S between the exhaust pressure and the pressure of the intermediate cavity is detected, if S is greater than S1, the nHz is increased or decreased within T2 seconds, and if S is less than S1, the nHz is increased or decreased within T1 seconds; the compressor is started and stopped according to manual start-stop signals or according to liquid level switch control in the standby process, the compressor is stopped when the high liquid level switch is closed, and the compressor is started when the middle liquid level switch is disconnected.
3. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the control of the variable-frequency water pump is specifically as follows:
in order to ensure that the outlet water temperature of the water heater can reach the set temperature quickly, the control of the variable frequency water pump is increased because the frequency increasing and decreasing speed of the compressor is limited; when the water heater is started, because the frequency raising speed is lower after the compressor is started, in order to enable the outlet water temperature to quickly reach the set temperature, the output of the variable frequency water pump is reduced, and the water flow is reduced so as to achieve the purpose of high outlet water temperature; when the outlet water temperature of the unit rises along with the rise of the frequency of the compressor, the output of the variable frequency water pump is increased, so that the higher outlet water temperature is kept and the water tank is filled with hot water more quickly.
4. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the control of heating and defrosting specifically comprises the following steps:
the defrosting condition of the unit is that the ambient temperature is lower than a set value, the ambient temperature-fin evaporator temperature (outer coil temperature) is higher than the set value, the compressor running time is greater than the minimum compressor running time, the defrosting condition is quit, the fin evaporator temperature (outer coil temperature) is higher than the set value, the CO2 water heater adopts hot gas bypass defrosting, and the flow direction of a refrigerant during normal heating is as follows: compressor (1) -air cooler (2) -heat regenerator (3) -electronic expansion valve (4) — a finned evaporator (5), a heat regenerator (6), a gas-liquid separator (7) and a compressor (8); when the defrosting operation is performed, after the water heater reaches the defrosting condition, the defrosting bypass electromagnetic valve is opened, and the electronic expansion valve is closed (the defrosting bypass electromagnetic valve and the electronic expansion valve act simultaneously, and the compressor is not stopped, so that the probability of generating an air hammer of a refrigerant circulating system can be reduced, and the risk of pipeline vibration cracking is reduced); the refrigerant flows to the compressor (1), the defrosting bypass solenoid valve (7), the fin evaporator (5), the heat regenerator (3), the gas-liquid separator (6) and the compressor (1); turning off the variable frequency water pump, turning off the EC direct current fan, and defrosting the compressor without stopping; the purpose of the series of actions is to ensure that heat generated during heating operation of the compressor generates heat exchange in the evaporator as much as possible, so that accumulated frost on the evaporator is melted and heat waste caused by heat exchange with water and air in the air in a water system is avoided; in the defrosting process, the compressor enters a defrosting rotating speed (low-rotating-speed operation), which aims to reduce the flow speed of CO2 in a refrigerant system and increase the heat exchange efficiency of the CO2 and accumulated frost, so that the defrosting is performed as soon as possible; and the gas-liquid separator is provided with gas-liquid separator electric heating, and when defrosting control is carried out, the gas-liquid separator electric heating is started to provide extra heat for defrosting of the hot water unit.
5. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the control of the water inlet three-way valve is as follows:
when hot water in the water tank is not used for a long time, the main control unit opens the water inlet three-way valve after detecting that the temperature of the hot water in the water tank is reduced, so that a circulating water path is formed among the water tank, the variable-frequency water pump and the water heater, and then the main control unit starts the water heater unit to heat and raise the temperature of the water in the water tank;
when the environmental temperature is low in winter, particularly the temperature of minus ten or twenty and several degrees in northern areas, the unit needs to be protected from freezing, when the detected environmental temperature is lower than 0 ℃, any one of the temperature of a water tank or the temperature of outlet water is lower than a set value, the unit enters a freezing prevention mode, a water inlet three-way valve is closed, a loop is formed among the water tank, a variable-frequency water pump and a water heater, then a main control unit starts the water pump by a water pump signal, a compressor is started after the water pump runs to heat, the temperature of water in the water tank and water in a pipeline is raised, and when the water temperature (the temperature of the water tank or the temperature of the water in the water tank) is higher than the set value for freezing prevention, the unit is closed, the water pump is closed, and the water inlet three-way valve is closed.
6. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the control of the electronic expansion valve specifically comprises the following steps:
the electronic expansion valve is adjusted by keeping the temperature difference between the outlet temperature and the inlet temperature of the air cooler, so that the stable and efficient operation of the water heater is realized, and the exhaust temperature, the exhaust pressure and the like can be within normal ranges;
the control system defines: air cooler outlet temperature-inlet water temperature = approach temperature T;
the opening degree of the electronic expansion valve is adjusted by comparing the set approximate temperature target value TS with the difference T1 between the actual air cooler outlet temperature and the inlet water temperature and by PID calculation.
7. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the control of the electric heating of the gas-liquid separator specifically comprises the following steps:
the electric heating of the gas-liquid separator is used for preventing the heat stored by the compressor from being insufficient to fully remove frost accumulated on the evaporator during defrosting; when defrosting control is performed, the main control unit starts the gas-liquid separator to be electrically heated, and heat during defrosting is increased, so that accumulated frost on the evaporator can be thoroughly removed.
8. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the control of the intermediate pressure bypass electromagnetic valve specifically comprises the following steps:
the CO2 double-rotor variable frequency compressor needs to be ensured in the operation process: the exhaust pressure-intermediate cavity pressure is greater than S1Bar;
the function of the intermediate pressure bypass solenoid valve is that: when the exhaust pressure and the intermediate cavity pressure are less than or equal to S1Bar, the main control unit outputs a signal, opens the intermediate pressure bypass electromagnetic valve, enables the intermediate cavity pressure to be communicated with a CO2 double-rotor frequency conversion compressor return air pipeline through a pipeline, achieves the purpose of reducing the intermediate cavity pressure, reestablishes the pressure difference (the difference between the exhaust pressure and the intermediate cavity pressure is larger than S1), closes the intermediate pressure bypass electromagnetic valve after the operation for a period of time t, and can still ensure that the difference between the pressure difference and the pressure difference is larger than S1 after the electromagnetic valve is closed.
9. The high-stability variable-frequency heated water heater control system as claimed in claim 1, wherein: the control of the electric heating of the gas-liquid separator specifically comprises the following steps:
the electric heating of the gas-liquid separator is used for providing additional heat for defrosting except the heat of the compressor when the unit is defrosted;
the control method comprises the following steps: the electric heating of the gas-liquid separator is not started when the unit normally runs, when the unit enters a defrosting mode, the main control unit outputs a signal to start the electric heating of the gas-liquid separator, and when the condition that the unit exits the defrosting mode is reached, the main control unit outputs a signal to stop the electric heating of the gas-liquid separator.
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| CN202210748391.XA CN115200180A (en) | 2022-06-29 | 2022-06-29 | High-stability variable-frequency heated water heater control system |
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| CN202210748391.XA CN115200180A (en) | 2022-06-29 | 2022-06-29 | High-stability variable-frequency heated water heater control system |
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| JP2003074997A (en) * | 2001-09-04 | 2003-03-12 | Sanyo Electric Co Ltd | Supercritical refrigeration unit |
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| CN114234450A (en) * | 2021-12-24 | 2022-03-25 | 山东雅士股份有限公司 | Variable-frequency CO2Water heater unit and control method thereof |
| CN216644604U (en) * | 2021-12-28 | 2022-05-31 | 江苏苏净集团有限公司 | Water heating system for transcritical carbon dioxide single-stage and double-stage compression |
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2022
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|---|---|---|---|---|
| JP2003074997A (en) * | 2001-09-04 | 2003-03-12 | Sanyo Electric Co Ltd | Supercritical refrigeration unit |
| WO2013031591A1 (en) * | 2011-08-31 | 2013-03-07 | 三菱重工業株式会社 | Supercritical cycle and heat pump hot-water supplier using same |
| CN105593610A (en) * | 2013-09-30 | 2016-05-18 | 三菱重工业株式会社 | Heat pump system, and heat pump water heater |
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| CN114234450A (en) * | 2021-12-24 | 2022-03-25 | 山东雅士股份有限公司 | Variable-frequency CO2Water heater unit and control method thereof |
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