Disclosure of Invention
The invention aims to provide an intelligent air energy water heater and a using method thereof. The air energy water heater has the advantages of simple structure, more convenient control and comprehensive functions, can predict frosting and defrost after frosting, and prolongs the service life of the air energy water heater.
The technical scheme of the invention is as follows: an intelligent air energy water heater comprises a refrigerant loop, a water control loop and a variable frequency controller; the refrigerant loop comprises an evaporator, a first four-way valve, a gas-liquid separator, a compressor, a heat exchanger, a liquid storage tank, an expansion valve and a filter; the evaporator is connected with the end 1 of the first four-way valve, the end 2 of the first four-way valve is connected with the gas-liquid separator, the gas-liquid separator is connected with the compressor, and the compressor is connected with the end 3 of the first four-way valve; the 4 end of the first four-way valve is connected with a heat exchanger; the heat exchanger is connected with the liquid storage tank, the liquid outlet tank is connected with the filter through the expansion valve, and the filter is connected with the evaporator; the water control loop comprises a water tank, a water pump, a three-way valve, a one-way stop valve, an air pressure tank, a pressure gauge, a backwater temperature sensor, a second four-way valve and an opening degree adjusting valve; the water tank is connected with the heat exchanger, a water outlet of the water tank is connected with a water pump, the water pump is connected with a one-way stop valve through a three-way valve, the one-way stop valve is connected with a water outlet pipeline, and the water outlet pipeline is connected with a water return pipeline; the end 1 of the second four-way valve is connected with the heat exchanger, the end 2 is connected with the three-way valve, the end 3 is connected with the water return pipeline motor, and the end 4 is connected with the water inlet pipeline; the air pressure tank and the pressure gauge are connected to the water outlet pipeline; the return water temperature sensor is arranged on the return water pipeline; the opening regulator is connected to the water inlet pipeline; the variable frequency controller is respectively and electrically connected with the first four-way valve, the compressor, the water tank, the water pump, the pressure gauge, the second four-way valve, the backwater temperature sensor and the opening regulating valve; the variable frequency controller is also connected with an ambient temperature sensor and a relative humidity sensor;
when the air energy water heater defrosts, the compressed gas pressure value of the compressor is obtained, the compressed gas pressure value of the compressor under the normal non-frosting condition is obtained, the specific coefficient of the compressor and the compressed gas pressure value of the compressor is obtained, the gray prediction model is obtained by utilizing the specific coefficient and the running power of the compressor, the frosting fault degree is represented by the reduction degree of the specific coefficient, and then the frosting degree of the evaporator of the air energy water heater is judged by analyzing the mathematical expression of the gray prediction model.
The evaporator comprises a disc-shaped copper pipe, and the disc-shaped copper pipe is tightly attached or wound with the piezoelectric defrosting unit.
According to the intelligent air energy water heater, the plurality of electric vibrators are mounted around the disc-shaped copper pipe.
In the intelligent air energy water heater, the fixed part of the electric vibrator is fixed on the end face of the outdoor unit, and the movable part and the disc-shaped copper pipe are spaced.
According to the using method of the intelligent air energy water heater, the variable frequency controller collects the ambient temperature, the ambient relative humidity, the water pressure of the pipe network and the temperature of the tail end of the return water and collects the pressure data of the gas at the outlet of the compressor, so that the operation of the refrigerant loop and the water control loop is controlled, and the heating work and the defrosting work of the air energy water heater are realized.
In the use method of the intelligent air energy water heater, during heating, the refrigerant in the refrigerant loop absorbs heat energy in air in the evaporator copper pipe to be gasified, the refrigerant is compressed into high-temperature and high-pressure gas through the first four-way valve, the gas-liquid separator and the compressor, and the heat energy is released to water flowing through the heat exchanger to heat the water; after releasing the heat energy, the refrigerant returns to the evaporator again to carry out the next heat exchange after passing through the liquid storage tank, the expansion valve and the filter;
under the heating working mode, the water control loop realizes three working states including a circulating heating working state, a backwater heating working state and constant-temperature and constant-pressure water supply; in the circulating heating working state, when the variable frequency controller does not detect the condition that the temperature of the user water and the tail end return water in the return water pipeline is too low, the end 1 and the end 2 of the second four-way valve are communicated, and water flows out of the water tank, sequentially passes through the water pump, the three-way valve, the second four-way valve and the heat exchanger and then returns to the water tank again; after the variable frequency controller samples the water temperature of the water tank and executes a water temperature control algorithm, the operating parameters of the compressor and the operating parameters of the water pump are coordinated, so that the water temperature of the water tank is constant, and the optimal efficiency of the water heater is achieved; in a backwater heating working state, when the variable frequency controller detects that the temperature of the backwater at the tail end is lower than a set backwater tail end temperature lower limit threshold value, the end 1 and the end 3 of the second four-way valve are communicated, and water flows out of the water tank and then returns to the water tank again after sequentially passing through the water pump, the three-way valve, the one-way stop valve, the water outlet pipeline, the backwater pipeline, the second four-way valve and the heat exchanger; the variable frequency controller rapidly heats low-temperature water in the pipeline by controlling the rotating speed of the water pump and the power of the compressor, and injects high-temperature water in the water tank into the pipeline until the temperature of the tail end of the backwater reaches a set upper limit threshold of the temperature of the tail end of the backwater; in a constant-temperature and constant-pressure water supply state, when the variable-frequency controller detects water consumption of a user through a pressure gauge, the end 1 of the second four-way valve is communicated with the end 4, hot water flows out of the water tank and sequentially passes through the water pump, the three-way valve, the one-way stop valve and the water outlet pipeline to reach the user using end, the hot water meeting requirements is provided for the user, the running rotating speed of the water pump determines the running frequency of the water pump through a water supply constant-pressure control algorithm, and the water consumption pressure of the user is stable; the reduced hot water in the water tank is supplemented by controlling the opening of the opening regulating valve; meanwhile, the variable frequency controller operates a water temperature control algorithm to adjust the power of the compressor in real time, so that the low-temperature water injected by the opening adjusting valve is heated, and the temperature of the water tank is ensured.
According to the using method of the intelligent air energy water heater, the defrosting work is that the piezoelectric defrosting unit is tightly attached to or wound on the coil-shaped copper pipe, and the electric vibrator is arranged around the coil-shaped copper pipe of the evaporator; the variable frequency controller realizes strain stress and resonance stress defrosting by driving the piezoelectric defrosting unit and the electric vibrator, the frost attached to the copper pipe is crushed into small frost, and most of the crushed frost is vibrated to fall through vibration; meanwhile, the variable frequency controller switches the mode of the first four-way valve, the refrigerant absorbs the heat energy of water in the heat exchanger to be gasified, and after the refrigerant is compressed into high-temperature and high-pressure gas through the first four-way valve, the gas-liquid separator and the compressor, the heat energy is released to the frost attached to the copper pipe in the evaporator, the melting speed of the broken frost is increased, and the defrosting process of the air energy water heater is improved; after releasing the heat energy, the refrigerant returns to the heat exchanger again for next heat exchange after passing through the filter, the expansion valve and the liquid storage tank; under the defrosting working condition, the frequency conversion controller communicates the end 1 with the end 2 of the second four-way valve, high-temperature hot water in the water tank flows out of the water tank, sequentially passes through the water pump, the three-way valve and the second four-way valve, heat in the high-temperature hot water is absorbed by a refrigerant on the other side of the heat exchanger after reaching the heat exchanger, and the water after releasing the heat flows out of the heat exchanger and returns to the water tank again; meanwhile, the frequency conversion controller realizes the control of the thermal defrosting speed by adjusting the running speed of the water pump.
In the use method of the intelligent air energy water heater, a frosting prediction algorithm is arranged in the variable frequency controller, and frosting prediction is performed through the frosting prediction algorithm, and the steps are as follows:
(1) obtaining the ambient temperature T of the dayambAmbient relative humidity HambJudging whether the air energy water heater is in a frosting operation boundary range or not at present; if yes, entering the step (2); otherwise, quitting;
(2) executing a frosting prediction algorithm at the moment every delta T time, and defining that each parameter needs to be sampled by n data when the algorithm is judged to be executed every time, wherein the sampling period is Ts;
(3) Power P to the compressor
compAnd refrigerant high pressure gas pressure P
pressN data samples, denoted as: { P
comp(1),P
comp(2),…,P
comp(n) } and { P }
press(1),P
press(2),…,P
press(n) }; and obtaining the power of the compressor as P under the condition of normal non-frosting
comp(1),P
comp(2),…,P
compRefrigerant high pressure gas pressure at (n) } time
(4) Calculating the ratio of the refrigerant high-pressure gas pressure in the frosting operation boundary range to the refrigerant high-pressure gas pressure in the normal non-frosting condition:
obtaining a ratio array { λ (1), λ (2), …, λ (n) };
obtaining a Power array { P
comp(i) Minimum value of }
And maximum value
Using maximum and minimum values to find equal interval quantity
And establishing an equally spaced array of quantities
Wherein
With power array { P
comp(1),…,P
comp(n) is an independent variable discrete value, a ratio array { lambda (1), lambda (2), …, lambda (n) } is a dependent variable discrete value, and an interpolation algorithm is used to obtain an equal interval number set
Corresponding sequences
(5) Based on a one-time accumulation mode, sequence is matched
Generating a new sequence
Satisfy the requirement of
And establishing a differential equation based on the new sequence and the equal interval quantity:
wherein a is a development coefficient, and mu is an ash action amount;
solving the parameter vector to be estimated
And the differential equation is used for obtaining a gray prediction model
For the predicted sequence
Carrying out reduction to obtain a reduced sequence
The mathematical expression of the prediction model of (1):
(6) defining the association degree r:
(7) judging whether r is larger than or equal to zeta and zeta is a threshold value, if yes, entering step (8); otherwise, returning to the step (2);
(8) judging whether a is larger than or equal to theta and theta is a threshold value, if yes, the air energy water heater is in frosting fault operation, and entering the step (9); otherwise, entering the step (2);
(9) solving the frosting fault degree alpha as a/amaxAnd further obtaining the frosting fault degree alpha of the air energy water heater.
According to the using method of the intelligent air energy water heater, defrosting is carried out according to the obtained frosting degree, and the steps are as follows:
firstly, acquiring frosting degree alpha.
Dependence function delta as s (alpha) and function F
1=f
1(alpha), calculating the strain delta and the frequency F which are required to be generated by the piezoelectric defrosting unit when the frosting degree is alpha
1(ii) a Function of dependence
Calculation of the resulting strain delta and frequency F
1Voltage applied to the piezoelectric defrost unit
③ according to function A ═ h (alpha) and function F
2=f
2(alpha) calculating the amplitude A and frequency F of the frost formation required by the vibrator
2(ii) a Function of dependence
Calculating the amplitude A and frequency F of electric vibrator
2Time-driven power supply output current vector
Fourthly, controlling the first four-way valve to be switched from the heating mode to the defrosting mode and controlling the compressor power P according to the defrosting mode
compAs a function of the degree of frosting alpha
compObtaining a compressor running power set value as D _ front (alpha)
The quick and reliable defrosting is realized;
fifthly, the
And
respectively used as the power output voltage of the piezoelectric defrosting unit, the power output current of the electric vibrator and the running power set value of the compressor;
and sixthly, driving the piezoelectric unit, the vibrator, the first four-way valve and the compressor to defrost.
Compared with the prior art, the air energy water heater comprises a refrigerant loop, a water control loop and a variable frequency controller, the structures and the pipe network layout of the refrigerant loop and the water control loop are simpler, the switching control of working modes is convenient, the functions are comprehensive, the switching control of circulating heating, backwater heating and constant-temperature and constant-pressure water supply can be realized only by controlling the second four-way valve, and the simplicity of a control system is further realized; on the other hand, only adopt single frequency conversion water pump in the whole water route return circuit, when realizing cyclic heating, return water heating and constant temperature and pressure water supply, it all adopts the frequency conversion regulation scheme with the compressor, on the basis of simplifying system architecture, hardware cost and energy consumption cost by a wide margin, can effectively promote the stability of water supply temperature and pressure. In addition, the invention also provides a frosting prediction method, which can accurately and reliably predict whether the copper pipe is frosted and the frosting degree, and provides a basis for the optimized control of the subsequent defrosting. Secondly, the invention organically combines vibration defrosting, piezoelectric defrosting and hot defrosting, can effectively improve the defrosting effect, quickens the defrosting process, reduces the defrosting energy consumption, eliminates the great drop of the water temperature/room temperature, and improves the overall performance of the air energy water heater.
Detailed Description
The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.
The embodiment is as follows: an intelligent air energy water heater is shown in figure 1 and comprises a refrigerant loop 1, a water control loop 2 and a variable frequency controller 3; the refrigerant loop 1 comprises an evaporator 4, a first four-way valve 5, a gas-liquid separator 6, a compressor 7, a heat exchanger 8, a liquid storage tank 9, an expansion valve 10 and a filter 11; the evaporator 4 is connected with the end 1 of the first four-way valve 5, the end 2 of the first four-way valve 5 is connected with the gas-liquid separator 6, the gas-liquid separator 6 is connected with the compressor 7, and the compressor 7 is connected with the end 3 of the first four-way valve 5; the 4 end of the first four-way valve 5 is connected with a heat exchanger 8; the heat exchanger 8 is connected with a liquid storage tank, the liquid outlet tank is connected with a filter 11 through an expansion valve 10, and the filter 11 is connected with the evaporator 4; the water control loop 2 comprises a water tank 12, a water pump 13, a three-way valve 14, a one-way stop valve 15, an air pressure tank 16, a pressure gauge 17, a return water temperature sensor 18, a second four-way valve 19 and an opening degree adjusting valve 20; the water tank 12 is connected with the heat exchanger 8, the water outlet of the water tank 12 is connected with the water pump 13, the water pump 13 is connected with the one-way stop valve 15 through the three-way valve 14, the one-way stop valve 15 is connected with the water outlet pipeline 21, and the water outlet pipeline 21 is connected with the water return pipeline 22; the end 1 of the second four-way valve 19 is connected with the heat exchanger 8, the end 2 is connected with the three-way valve 14, the end 3 is connected with the water return pipeline 22 motor, and the end 4 is connected with the water inlet pipeline; the air pressure tank 16 and the pressure gauge 17 are connected to a water outlet pipeline 21; the return water temperature sensor 18 is arranged on the return water pipeline 22; the opening regulator is connected to the water inlet pipeline; the variable frequency controller 3 is respectively and electrically connected with the first four-way valve 5, the compressor 7, the water tank 12, the water pump 13, the pressure gauge 17, the second four-way valve 19, the backwater temperature sensor 18 and the opening regulating valve 20; the frequency conversion controller 3 is also connected with an ambient temperature sensor and a relative humidity sensor.
When the air energy water heater works in the implementation, the variable frequency controller 3 collects the ambient temperature, the ambient relative humidity, the water pressure of a pipe network and the temperature of the tail end of return water and collects the pressure data of outlet gas of the compressor 7, so that the operation of the refrigerant loop 1 and the water control loop 2 is controlled, and the heating work and the defrosting work of the air energy water heater are realized.
During heating operation, the refrigerant in the refrigerant circuit 1 absorbs heat energy in air in the copper pipe of the evaporator 4 to be gasified, the refrigerant is compressed into high-temperature and high-pressure gas through the first four-way valve 5, the gas-liquid separator 6 and the compressor 7, and the heat energy is released to water flowing through the heat exchanger 8 to heat the water; after releasing the heat energy, the refrigerant returns to the evaporator 4 again for the next heat exchange after passing through the liquid storage tank 9, the expansion valve 10 and the filter 11;
under the heating working mode, the water control loop 2 realizes three working states including a circulating heating working state, a backwater heating working state and constant-temperature and constant-pressure water supply; in the circulating heating working state, when the variable frequency controller 3 does not detect the conditions that the temperature of the water used by a user and the temperature of the tail end return water in the water return pipeline 22 are too low, the end 1 and the end 2 of the second four-way valve 19 are communicated, the water flows out of the water tank 12, and then flows back to the water tank 12 again after sequentially passing through the water pump 13, the three-way valve 14, the second four-way valve 19 and the heat exchanger 8; after the variable frequency controller 3 samples the water temperature of the water tank 12 and executes a water temperature control algorithm, the operation parameters of the compressor 7 and the operation parameters of the water pump 13 are coordinated, so that the water temperature of the water tank 12 is constant, and the optimal efficiency of the water heater is achieved; in a backwater heating working state, when detecting that the temperature of the backwater at the tail end is lower than a set backwater tail end temperature lower limit threshold value, the frequency conversion controller 3 communicates the end 1 and the end 3 of the second four-way valve 19, and water flows out of the water tank 12 and then returns to the water tank 12 again after sequentially passing through the water pump 13, the three-way valve 14, the one-way stop valve 15, the water outlet pipeline 21, the backwater pipeline 22, the second four-way valve 19 and the heat exchanger 8; the variable frequency controller 3 rapidly heats low-temperature water in the pipeline by controlling the rotating speed of the water pump 13 and the power of the compressor 7, and injects high-temperature water in the water tank 12 into the pipeline until the temperature of the tail end of the backwater reaches the upper limit threshold of the temperature of the tail end of the backwater; in a constant-temperature and constant-pressure water supply state, when the variable-frequency controller 3 detects water consumption of a user through a pressure gauge 17, the end 1 and the end 4 of the second four-way valve 19 are communicated, hot water flows out of the water tank 12 and sequentially passes through the water pump 13, the three-way valve 14, the one-way stop valve 15 and the water outlet pipeline 21 to reach the user end, the hot water meeting requirements is provided for the user, the running rotating speed of the water pump 13 determines the running frequency of the water pump 13 through a water supply constant-pressure control algorithm, and the water consumption pressure of the user is stable; the reduced hot water in the water tank 12 is supplemented by controlling the opening of the opening regulating valve 20; meanwhile, the variable frequency controller 3 operates a water temperature control algorithm to adjust the power of the compressor 7 in real time, and heats the low-temperature water injected from the opening degree adjusting valve 20 to ensure the temperature of the water in the water tank 12.
The defrosting operation is to closely attach or wind the piezoelectric defrosting unit on the disc-shaped copper pipe, the electric vibrators are installed around the evaporator disc-shaped copper pipe, as shown in fig. 2, 3 and 4, the evaporator 4 comprises the disc-shaped copper pipe, the piezoelectric defrosting unit 23 is closely attached or wound on the disc-shaped copper pipe, and a plurality of electric vibrators are installed around the disc-shaped copper pipe. The variable frequency controller drives the piezoelectric defrosting unit and the electric vibrator to realize strain stress and resonance stress defrosting, the frost attached to the copper pipe is crushed into small frost, and most of the crushed frost is vibrated down through vibration; meanwhile, the variable frequency controller switches the mode of the first four-way valve, the refrigerant absorbs the heat energy of water in the heat exchanger to be gasified, and after the refrigerant is compressed into high-temperature and high-pressure gas through the first four-way valve, the gas-liquid separator and the compressor, the heat energy is released to the frost attached to the copper pipe in the evaporator, the melting speed of the broken frost is increased, and the defrosting process of the air energy water heater is improved; after releasing the heat energy, the refrigerant passes through the filter, the expansion valve and the liquid storage tank and then returns to the heat exchanger again for next heat exchange. Under the defrosting working condition, the frequency conversion controller communicates the end 1 with the end 2 of the second four-way valve, high-temperature hot water in the water tank flows out of the water tank, sequentially passes through the water pump, the three-way valve and the second four-way valve, heat in the high-temperature hot water is absorbed by a refrigerant on the other side of the heat exchanger after reaching the heat exchanger, and the water after releasing the heat flows out of the heat exchanger and returns to the water tank again; meanwhile, the frequency conversion controller realizes the control of the thermal defrosting speed by adjusting the running speed of the water pump. The vibration unit is composed of a plurality of electric vibrators, the fixed parts of the electric vibrators are respectively fixed on the end face of the outdoor unit, and the movable parts and the disc-shaped copper pipes are spaced at a certain distance. The output amplitude and frequency parameters of the vibrators, the installation quantity and the installation positions can be comprehensively determined through theoretical simulation analysis and experimental test results, as well as cost and system complexity. As known from physics knowledge, when the copper pipe frosts, the natural vibration frequency of the copper pipe changes, and the frequency value is related to the frosting degree. When the frequency of the external vibration excitation is equal to or close to the natural frequency, the frosted copper tube resonates. At the moment, the stress on the frost attached to the copper pipe can be adjusted by controlling the amplitude of the external vibration. When the external excitation vibration amplitude reaches a certain value, frost attached to the copper pipe is shattered, and most shattered frost falls along with vibration. The amplitude and the frequency of the vibrator are controlled by the amplitude and the frequency of the output current of the connected driving power supply, and the aim of quickly and efficiently defrosting is fulfilled by optimally controlling the current parameters of the driving power supply of the vibrator. When the disc-shaped copper pipe is in a frosted or ice-coated state, the electric vibrator is driven to apply vibration to the copper pipe, the vibration frequency of the electric vibrator is equal to or close to the natural frequency of the disc-shaped copper pipe when frosting occurs, resonance is further generated, on one hand, frost attached to the copper pipe is broken due to huge resonance stress, on the other hand, the frost broken due to thermal expansion and the resonance stress is vibrated, and the defrosting process is accelerated. The winding or pasting distance of the piezoelectric defrosting unit must comprehensively consider the heat exchange efficiency and the defrosting efficiency, and the heat exchange efficiency and the defrosting efficiency cannot be too large or too small. If the distance is too large, the defrosting effect is not good; and the spacing is too small, which leads to poor heat exchange efficiency, and the spacing value can be determined by optimizing actual test data. The piezoelectric defrosting unit is connected to the control power supply, and the purpose of optimally controlling defrosting is achieved by adjusting the electrical parameters of the respective power supplies.
The invention is provided with a frosting prediction algorithm in the variable frequency controller, and the frosting prediction algorithm comprises the following specific steps:
(1) obtaining the ambient temperature T of the dayambAmbient relative humidity HambJudging whether the air energy water heater is in a frosting operation boundary range or not; if yes, entering the step (2); otherwise, quitting;
(2) executing a frosting prediction algorithm at the moment every delta T time, and defining that each parameter needs to be sampled by n data when the algorithm is judged to be executed every time, wherein the sampling period is Ts;
(3) Power P to the compressor
compAnd refrigerant high pressure gas pressure P
pressSampling n dataRespectively noted as: { P
comp(1),P
comp(2),…,P
comp(n) } and { P }
press(1),P
press(2),…,P
press(n) }; and obtaining the power of the compressor as P under the condition of normal non-frosting
comp(1),P
comp(2),…,P
compRefrigerant high pressure gas pressure at (n) } time
(4) Calculating the ratio of the refrigerant high-pressure gas pressure in the frosting operation boundary range to the refrigerant high-pressure gas pressure in the normal non-frosting condition:
obtaining a ratio array { λ (1), λ (2), …, λ (n) };
obtaining a Power array { P
comp(i) Minimum value of }
And maximum value
Using maximum and minimum values to find equal interval quantity
And establishing an equally spaced array of quantities
Wherein
With power array { P
comp(1),…,P
comp(n) is an independent variable discrete value, a ratio array { lambda (1), lambda (2), …, lambda (n) } is a dependent variable discrete value, and an interpolation algorithm is used to obtain an equal interval number set
Corresponding sequences
(5) Based on a one-time accumulation mode, sequence is matched
Generating a new sequence
Satisfy the requirement of
And establishing a differential equation based on the new sequence and the equal interval quantity:
wherein a is a development coefficient, and mu is an ash action amount;
solving the parameter vector to be estimated
And the differential equation is used for obtaining a gray prediction model
For the predicted sequence
Carrying out reduction to obtain a reduced sequence
The mathematical expression of the prediction model of (1):
(6) defining the association degree r:
(7) judging whether r is larger than or equal to zeta, wherein zeta is a threshold value and is 0.95, and if yes, entering the step (8); otherwise, returning to the step (2);
(8) judging whether a is larger than or equal to theta, if theta is a threshold value and is 0.5, if yes, the air energy water heater is in frosting fault operation, and entering the step (9); otherwise, entering the step (2);
(9) solving the frosting fault degree alpha as a/amaxAnd further obtaining the frosting fault degree alpha of the air energy water heater.
And obtaining the frosting degree alpha through the frosting prediction algorithm. On the basis, the frosting degree alpha and the strain delta and the frequency F which are required to be generated by the piezoelectric defrosting unit during reliable defrosting are obtained according to experimental test data, theoretical simulation analysis and a data fitting method
1Is s (alpha) and F
1=f
1(α); secondly, according to strain parameters delta and F of the piezoelectric defrosting unit
1Determining a mathematical relationship with the characteristics of the driving power supply voltage
And will be
The reference value of the output voltage of the driving power supply is used for controlling the driving power supply, and reliable piezoelectric strain ice breaking is realized. Similarly, the frosting degree alpha and the amplitude A and the frequency F which are required to be generated by the electric vibrator are obtained according to experimental test data, theoretical simulation analysis and a data fitting method
2The mathematical relationship of (a) to (h (α) and (F)
2=f
2(α). According to amplitude A and frequency F
2Determining a mathematical relationship with the characteristics of the electric vibrator drive supply current
And will be
The reference value of the output current of the driving power supply is used for controlling the driving power supply to realize vibration defrosting. Similarly, the compressor power P is obtained by experimental test data, theoretical simulation analysis and data fitting method
compMathematical relationship P with frosting degree alpha
compD _ front (α), and compressor power P is also set
compThe reference value of the output power of the compressor is used for controlling the reference value, so that the rapid defrosting is realized. The method comprises the following specific steps:
firstly, acquiring frosting degree alpha.
Dependence function delta as s (alpha) and function F
1=f
1(alpha), calculating the strain delta and the frequency F which are required to be generated by the piezoelectric defrosting unit when the frosting degree is alpha
1(ii) a According to function
Calculation of the resulting strain delta and frequency F
1Voltage applied to the piezoelectric defrost unit
③ according to function A ═ h (alpha) and function F
2=f
2(alpha) calculating the amplitude A and frequency F of the frost formation required by the vibrator
2(ii) a Function of dependence
Calculating the amplitude A and frequency F of electric vibrator
2Time-driven power supply output current vector
Fourthly, controlling the first four-way valve to be switched from the heating mode to the defrosting mode and controlling the compressor power P according to the defrosting mode
compAs a function of the degree of frosting alpha
compObtaining a compressor running power set value as D _ front (alpha)
Realize the high speedReliable defrosting;
fifthly, the
And
respectively used as the power output voltage of the piezoelectric defrosting unit, the power output current of the electric vibrator and the running power set value of the compressor;
and sixthly, driving the piezoelectric unit, the vibrator, the first four-way valve and the compressor to defrost.
In order to further explain the whole working algorithm flow of the air energy water heater, as shown in fig. 5, the algorithm is realized by adopting a timing operation mode, and is triggered by timer timing interruption, and the steps are as follows:
program entry
Second, run the frosting judgment algorithm subroutine, and judge whether frosting is present? If yes, entering the step III; otherwise, entering the step IV;
obtaining the frosting degree alpha, operating a defrosting control method and exiting the program;
acquiring data of the pressure gauge and judging whether the user uses water? If yes, go to step (v); otherwise, go to step sixthly;
running a water supply pressure control algorithm, a water tank water temperature control algorithm and a water tank liquid level control algorithm, and exiting the program;
sixthly, acquiring return water temperature data and judging whether the return water temperature is lower than a lower limit temperature threshold or in a return water heating state? If yes, entering step (c); otherwise, entering step ninthly;
seventhly, setting the temperature of the return water to be in a return water heating state, operating a return water temperature control algorithm, and judging whether the return water temperature reaches an upper limit temperature threshold value? If yes, go to step ((R)); otherwise, the program exits;
eighthly, exiting the backwater heating state, and exiting the program;
ninthly, operating a cyclic heating control algorithm, and withdrawing a program;
the program in the red (R) is exited;
in summary, the air energy water heater provided by the invention comprises the refrigerant loop, the water control loop and the variable frequency controller, the structures and the pipe network layouts of the refrigerant loop and the water control loop are simpler, the switching control of the working modes is convenient, the functions are comprehensive, the switching control of the circulating heating, the backwater heating and the constant-temperature and constant-pressure water supply can be realized only by controlling the second four-way valve, and the simplicity of a control system is further realized; on the other hand, only adopt single frequency conversion water pump in the whole water route return circuit, when realizing cyclic heating, return water heating and constant temperature and pressure water supply, it all adopts the frequency conversion regulation scheme with the compressor, on the basis of simplifying system architecture, hardware cost and energy consumption cost by a wide margin, can effectively promote the stability of water supply temperature and pressure. In addition, the invention also provides a frosting prediction method, which can accurately and reliably predict whether the copper pipe is frosted and the frosting degree, and provides a basis for the optimized control of the subsequent defrosting. Secondly, the invention organically combines vibration defrosting, piezoelectric defrosting and hot defrosting, can effectively improve the defrosting effect, quickens the defrosting process, reduces the defrosting energy consumption, eliminates the great drop of the water temperature/room temperature, and improves the overall performance of the air energy water heater.