CN108266898B - Defrosting control method and system for air energy water heater - Google Patents

Defrosting control method and system for air energy water heater Download PDF

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Publication number
CN108266898B
CN108266898B CN201611252375.2A CN201611252375A CN108266898B CN 108266898 B CN108266898 B CN 108266898B CN 201611252375 A CN201611252375 A CN 201611252375A CN 108266898 B CN108266898 B CN 108266898B
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temperature
defrosting
water
dry
unit
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CN108266898A (en
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沙保国
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Qingdao Haier New Energy Electric Appliance Co Ltd
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Qingdao Haier New Energy Electric Appliance Co Ltd
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H4/00Fluid heaters characterised by the use of heat pumps
    • F24H4/02Water heaters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00Details
    • F24H9/20Arrangement or mounting of control or safety devices
    • F24H9/2007Arrangement or mounting of control or safety devices for water heaters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B47/00Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02Defrosting cycles
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00Arrangement or mounting of control or safety devices
    • F25B49/02Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2347/00Details for preventing or removing deposits or corrosion
    • F25B2347/02Details of defrosting cycles
    • F25B2347/023Set point defrosting
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00Sensing or detecting of parameters; Sensors therefor
    • F25B2700/11Sensor to detect if defrost is necessary
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19Pressures
    • F25B2700/193Pressures of the compressor
    • F25B2700/1931Discharge pressures
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21Temperatures
    • F25B2700/2116Temperatures of a condenser
    • F25B2700/21161Temperatures of a condenser of the fluid heated by the condenser
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21Temperatures
    • F25B2700/2117Temperatures of an evaporator
    • F25B2700/21171Temperatures of an evaporator of the fluid cooled by the evaporator
    • F25B2700/21172Temperatures of an evaporator of the fluid cooled by the evaporator at the inlet
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21Temperatures
    • F25B2700/2117Temperatures of an evaporator
    • F25B2700/21171Temperatures of an evaporator of the fluid cooled by the evaporator
    • F25B2700/21173Temperatures of an evaporator of the fluid cooled by the evaporator at the outlet

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Defrosting Systems (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)

Abstract

Hair brushThe invention discloses a defrosting control method for an air energy water heater, which comprises the following steps: s1, detecting the dry bulb temperature T of the air in the current environment of the unit in real timeDry ballAnd wet bulb temperature TWet ball(ii) a S2, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballCalculating to obtain the dew point temperature T of the air in the current environmentd(ii) a S3, dew point temperature TdAnd when the first preset condition is met, controlling the unit to perform defrosting treatment. The invention can accurately judge the influence of the change of the environmental humidity on frosting and defrosting, determine the time node needing to enter the defrosting according to the change of the environmental humidity, can achieve the aim of accurately controlling the defrosting, and avoid the defect of misjudgment caused by not considering the influence of the humidity on frosting.

Description

Defrosting control method and system for air energy water heater
Technical Field
The invention belongs to the technical field of water heaters, and particularly relates to a defrosting control method and system for an air energy water heater.
Background
The air energy heat pump water heater uses the inverse Carnot cycle principle to drive the compressor to run by a small amount of electric energy to discharge high-temperature and high-pressure gas; high-temperature high-pressure gas enters the double-pipe heat exchanger to release heat, the released heat is continuously absorbed by cold water in the water-side heat exchanger, then low-temperature low-pressure gas generated by throttling absorbs heat from environmental working conditions, the heat is sucked into the compressor through a gas suction port of the compressor, then the high-temperature high-pressure gas is continuously compressed and discharged, and the cycle is repeated; the low-temperature water in the water side heat exchanger absorbs the heat released by the high-temperature and high-pressure gas discharged by the compressor, so that the low-temperature water is heated to the required high-temperature water for the equipment for preparing hot water used by the domestic hot water of users.
With the gradual improvement of the development of the industrial technology, the design of defrosting control is developed from original mechanical timing defrosting to the current intelligent defrosting, and the current main defrosting schemes comprise a timing defrosting scheme, a timing and temperature sensor defrosting scheme and a double-sensor defrosting scheme.
The timing defrosting scheme is that defrosting of the evaporator is carried out at fixed intervals from the operation of the heat pump, feedback signals are not needed to be provided for timing defrosting, whether the heat pump is frosted or not cannot be judged, and moreover, frosting changes caused by changes of environmental working conditions cannot be accurately judged; the principle of defrosting of the timing and temperature sensor is as follows: when the evaporator side frosts, the temperature of the coil pipe is reduced to a certain value when frosting to a certain degree, so that the defrosting is carried out after the heat pump unit continuously operates for a certain time difference, the frosting is avoided to a certain degree under the high-temperature working condition, but the condition that the frosting is not carried out under the low-temperature working condition cannot be effectively controlled; the double-sensor defrosting scheme is to detect the difference between the ambient temperature at the evaporator side and the temperature of the evaporator coil as the basis for judging frosting, and although the influence of humidity cannot be considered due to the change of the working condition of the low-temperature environment, the frosting condition under the conditions of low temperature and different humidity cannot be accurately processed, and the erroneous judgment still can be generated.
The present invention has been made in view of this situation.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and aims to provide a control method of an air energy water heater, which can accurately control a unit to enter a defrosting procedure under the condition of low temperature and different environmental humidity, so that the air energy water heater achieves the purposes of energy conservation, environmental protection and higher reliability.
In order to solve the technical problems, the invention adopts the technical scheme that:
the invention discloses a defrosting control method for an air energy water heater, which comprises the following steps:
s21, detecting the dry bulb temperature T of the air in the current environment of the unit in real timeDry ballAnd wet bulb temperature TWet ball
S22, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballCalculating to obtain the dew point temperature T of the air in the current environmentd
S23, at least dew point temperature TdAnd dry bulb temperature TDry ballAnd when the first preset condition is met, controlling the unit to enter defrosting treatment.
Further, before step S23, the method further includes: detecting the evaporating temperature T of an evaporator by a coil temperature sensore
Further, in step S23, the first preset condition is: evaporation temperature TeDew point temperature T is less than or equal todAnd dry bulb temperature TDry ball< first preset temperature.
Further, in step S23, the dew point temperature TdAnd (b) aBall temperature TDry ballWhen the first preset condition is not met, the following steps are carried out:
s24 real-time detection of water temperature TDischarging waterTemperature T of inlet waterInflow waterAnd the exhaust pressure change rate PdCalculating the difference delta T between the water outlet temperature and the water inlet temperature at the same time;
s25, judging the water outlet temperature TDischarging waterTemperature T of inlet waterInflow waterAnd the exhaust pressure change rate PdWhether a second preset condition is met or not is judged, and if yes, the unit is controlled to carry out defrosting treatment; if not, return is made to step S21.
Further, the second preset condition is that: rate of change of exhaust pressure PdThe temperature is continuously three times larger than a first preset value, and the difference delta T between the current water outlet temperature and the current water inlet temperature1< delta T difference between the water outlet temperature at the previous unit time and the water inlet temperature at the previous unit time2
The invention also aims to provide a defrosting control method for the air energy water heater, which comprises the following steps: in the working process of the unit, the dew point temperature T of the air in the current environment is obtained in real timed(ii) a The dew point temperature TdAnd on the premise of meeting the first preset condition, when the unit meets the second preset condition, controlling the unit to enter defrosting treatment.
Further, the dew point temperature T of the air in the current environment is obtaineddThe method specifically comprises the following steps:
s311, detecting the dry bulb temperature T of the air in the current environment of the unit in real timeDry ballAnd wet bulb temperature TWet ball
S312, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballObtaining the relative humidity f of the air in the current environment of the unit;
s313, calculating and obtaining the dew point temperature T of the air in the current environment according to the relative humidity fd
Further, the first preset condition is that: evaporation temperature TeDew point temperature T is less than or equal todAnd dry bulb temperature TDry ball< a first preset temperature;
the second preset condition is as follows: rate of change of exhaust pressure PdThe temperature is continuously three times larger than a first preset value, and the difference delta T between the current water outlet temperature and the current water inlet temperature1< delta T difference between the water outlet temperature at the previous unit time and the water inlet temperature at the previous unit time2
Wherein the evaporation temperature TeThe exhaust pressure change rate P is detected by a coil temperature sensor of the evaporatordThe temperature of the outlet water is detected by a pressure sensor at the outlet end of the compressor, the temperature of the outlet water is detected by a temperature sensor of the outlet water of the water outlet pipeline, and the temperature of the inlet water is detected by a temperature sensor of the inlet water of the water inlet pipeline.
Further, still include:
the unit is controlled to quit defrosting when any one of the following conditions is met;
t detected continuously for a first preset timeDefrosting creamNot lower than a second predetermined value;
and the continuous defrosting operation time reaches the set time.
It is still another object of the present invention to provide an air-powered water heater defrosting control system comprising:
a dew point temperature acquisition module for acquiring the temperature T of the dry bulbDry ballAnd wet bulb temperature TWet ballCalculating to obtain the dew point temperature T of the air in the current environmentd
A first control module and/or a second control module;
a first control module for determining dew point temperature TdWhen the first preset condition is met, controlling the unit to perform defrosting treatment;
a sensor module, the sensor module comprising: for detecting the temperature T of the dry bulbDry ballDry bulb temperature sensor for detecting wet bulb temperature TWet ballA wet bulb temperature sensor, a pressure sensor for detecting the discharge pressure at the outlet end of the compressor, an outlet water temperature sensor for detecting the outlet water temperature in the outlet water pipeline, an inlet water temperature sensor for detecting the inlet water temperature in the inlet water pipeline, and a coil temperature sensor for detecting the evaporation temperature of the evaporator;
The second control module is used for meeting any one of the following conditions after the first control module controls the unit to defrost and controlling the unit to quit defrosting;
t detected continuously for a first preset timeDefrosting creamNot lower than a second predetermined value;
and the continuous defrosting operation time reaches the set time.
After the technical scheme is adopted, compared with the prior art, the invention has the following beneficial effects.
According to the invention, the dry bulb temperature sensor and the wet bulb temperature sensor are arranged on the air inlet end of the evaporator, the dry bulb temperature and the wet bulb temperature are detected, the dew point temperature of the current environment is obtained according to the dry bulb temperature and the wet bulb temperature, the unit is controlled to carry out defrosting treatment by taking the dew point temperature meeting a first preset condition as a reference, and the influence of the environment humidity on frosting and defrosting is fully considered, so that unnecessary defrosting treatment is avoided, the waste of resources is reduced, meanwhile, a defrosting program can be entered at a relatively reasonable time node, the reliability of defrosting is also improved, the unit defrosting can be controlled more accurately, and the aim of improving the heating effect is achieved.
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention to the right. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:
FIG. 1 is a flow chart of a defrosting control method for an air energy water heater according to an embodiment of the invention;
FIG. 2 is a flow chart of a defrosting control method for an air energy water heater according to a second embodiment of the invention;
FIG. 3 is a flow chart of a defrosting control method for an air energy water heater according to a third embodiment of the invention;
FIG. 4 is a flow chart of a defrosting control method for an air energy water heater according to a fourth embodiment of the present invention;
FIG. 5 is a schematic structural diagram of an air energy water heater according to an embodiment of the invention;
FIG. 6 is a functional block diagram of a defrosting control system of an air-powered water heater according to an embodiment of the present invention.
In the figure: 1. a compressor; 2. a pressure sensor; 3. a condenser; 4. a throttling element; 5. a dry bulb temperature sensor; 6. an effluent temperature sensor; 7. an inlet water temperature sensor; 8. a coil temperature sensor; 9. an evaporator; 10. a wet bulb temperature sensor; 11. a fan; 100. a sensor module; 200. a dew point temperature acquisition module; 300. a first control module; 400. and a second control module.
It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.
In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The invention discloses a defrosting control method and a defrosting control system for an air energy water heater, which can judge frosting and defrosting more accurately according to the change of the ambient humidity of the water heater, thereby eliminating the influence of unnecessary defrosting on the heating effect of a heat pump unit in winter.
Example one
As shown in fig. 1, an embodiment of the invention discloses a flow chart of a defrosting control method for an air energy water heater, which comprises the following steps:
s21, detecting dry bulb temperature T of air in current environment of real-time unitDry ballAnd wet bulb temperature TWet ball
In this embodiment, the unit is an air-source water heater, and a dry-bulb temperature detection module and a wet-bulb temperature detection module are arranged at an air inlet end of an evaporator of the air-source water heater, where the air inlet end is located outdoors, and the dry-bulb temperature T isDry ballThe dry bulb temperature detection module arranged at the air inlet end of the evaporator detects the wet bulb temperature TWet ballThe wet bulb temperature detection module is also arranged at the air inlet end of the evaporator and used for detecting the temperature of the wet bulb. In this embodiment, the dry bulb temperature detection module is a dry bulb sensor, and the wet bulb temperature detection module is a wet bulb sensor.
S22, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballCalculating to obtain the dew point temperature T of the air in the current environmentd
In this embodiment, the temperature T of the dry bulb is determinedDry ballAnd wet bulb temperature TWet ballObtaining the relative humidity f of the current air, and then calculating the dew point temperature T of the air in the current environment according to the relative humidity f of the aird. Wherein, TdObtained by the following calculation formulaTo:
Td=(log(f×E0×10at/(b+t)/6.11)-1×a-1)-1×b;
wherein E0 is saturated water vapor pressure when air temperature is 0 deg.C, E0 is 6.11hPa, a is first parameter, b is second set parameter, and f is relative humidity of air, and can be determined according to dry bulb temperature TDry ballAnd wet bulb temperature TWet ballCalculated or by looking up an air humidity table.
S23, at least dew point temperature TdAnd when the first preset condition is met, controlling the unit to enter defrosting treatment.
The dew point temperature T obtained through the steps S21 and S22dThe dew point temperature TdAnd dry bulb temperature TDry ballComparing with a first preset condition preset by the water heater if the dew point temperature TdAnd dry bulb temperature TDry ballAnd if the first preset condition is met, controlling the unit to carry out defrosting treatment, and accurately controlling the time point of entering defrosting.
According to the invention, the dry bulb temperature sensor and the wet bulb temperature sensor are arranged on the air inlet end of the evaporator, the dry bulb temperature and the wet bulb temperature are detected, the dew point temperature of the current environment is obtained according to the dry bulb temperature and the wet bulb temperature, the unit is controlled to carry out defrosting treatment by taking the dew point temperature meeting a first preset condition as a reference, and the influence of the environment humidity on frosting and defrosting is fully considered, so that unnecessary defrosting treatment is avoided, the waste of resources is reduced, meanwhile, a defrosting program can be entered at a relatively reasonable time node, the reliability of defrosting is also improved, the unit defrosting can be controlled more accurately, and the heating effect is improved.
Example two
As shown in fig. 2, an embodiment of the present invention discloses a flow chart of another defrosting control method for an air energy water heater, which specifically includes the following steps:
s21, detecting the temperature T of the dry bulb in real timeDry ballAnd wet bulb temperature TWet ball
In this embodiment, the unit is an air energy water heater, and the air energy water heater is located in outdoor evaporationThe air inlet end of the device is provided with a dry bulb temperature detection module and a wet bulb temperature detection module, wherein the dry bulb temperature TDry ballThe temperature T of wet bulb is detected by a dry bulb temperature detection module arranged at the air inlet end of the evaporatorWet ballThe temperature detection module is also arranged on the air inlet end of the evaporator and is used for detecting the temperature of the wet bulb; in this embodiment, the dry bulb temperature detection module is a dry bulb sensor, and the wet bulb temperature detection module is a wet bulb sensor.
S22, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballCalculating to obtain the dew point temperature T of the air in the current environmentd
In this embodiment, the temperature T of the dry bulb is determinedDry ballAnd wet bulb temperature TWet ballObtaining the relative humidity f of the current air, and then calculating the dew point temperature T of the air in the current environment according to the relative humidity f of the aird. Wherein, TdThe following calculation formula is used to obtain:
Td=(log(f×E0×10at/(b+t)/6.11)-1×a-1)-1×b;
wherein, E0: the saturated water vapor pressure when the air temperature is 0 ℃ is taken as E0 ═ 6.11hPa, a is taken as a first set parameter, b is taken as a second set parameter, and f is taken as the relative humidity of the air.
S23, detecting the evaporation temperature T of the evaporator in real timee
In this embodiment, a coil temperature sensor is arranged on the outdoor evaporator of the air energy water heater, and the coil temperature sensor detects the T of the evaporator in real timee
S24, judging the dew point temperature TdAnd dry bulb temperature TDry ballAnd if the first preset condition is not met, controlling the unit to perform defrosting treatment if the first preset condition is met, and otherwise, entering the step S25.
Wherein the first preset condition is an evaporation temperature TeDew point temperature T is less than or equal todAnd dry bulb temperature TDry ball< first preset temperature. The first preset temperature is in the range of 5 ℃ and 9 DEG C]Preferably 7 deg.C.
The following is a specific example of the defrosting process of the air energy water heater:
assuming an evaporation temperature TeAt 10 ℃ and a dry bulb temperature TDry ballIs 4 ℃ depending on the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballCalculated dew point temperature TdAt 15 ℃ here, Te=10℃<TdDry bulb temperature T15 ℃ Dry ball4 ℃ < first preset temperature ═ 7 ℃, so the dew point temperature TdAnd meeting a first preset condition, and controlling the unit to carry out defrosting treatment.
S25 real-time detection of water temperature TDischarging waterTemperature T of inlet waterInflow waterAnd the exhaust pressure change rate PdAnd calculating the difference delta T between the water outlet temperature and the water inlet temperature at the same time.
In this embodiment, an outlet water temperature sensor is disposed on the outlet water pipeline, and the outlet water temperature sensor is used to detect the temperature of the outlet water to obtain TDischarging waterThe water inlet pipeline is provided with a water inlet temperature sensor, and the water inlet temperature sensor is used for detecting T of the temperature of inlet waterInflow waterAccording to the temperature T of the outlet waterDischarging waterAnd the temperature T of the inlet waterInflow waterObtaining the temperature difference delta T between the two; arranging a pressure sensor at the outlet end of the compressor, detecting the exhaust pressure of the compressor in real time by using the pressure sensor to obtain the numerical value of the exhaust pressure, and calculating to obtain the change rate P of the exhaust pressured
S26, judging the water outlet temperature TDischarging waterTemperature T of inlet waterInflow waterAnd the exhaust pressure change rate PdWhether a second preset condition is satisfied, if yes, go to step S27: controlling the unit to enter defrosting treatment; if not, return is made to step S22.
The second predetermined condition being a rate of change of exhaust pressure PdThe temperature is continuously three times larger than a first preset value, and the difference delta T between the current water outlet temperature and the current water inlet temperature1< delta T difference between the water outlet temperature at the previous unit time and the water inlet temperature at the previous unit time2. The first predetermined value is obtained according to a plurality of tests and is stored in the water heater in advance.
In particular, by means of pressureThe force sensor detects the discharge pressure change rate of the discharge port of the compressor in unit time (which can be 60 seconds), namely, the current discharge pressure value is detected firstly, then the discharge pressure after 60 seconds is detected, the two discharge pressures are subtracted and then divided by 60 seconds, and then the discharge pressure change rate P can be obtainedd. Meanwhile, the current water outlet temperature and the current water inlet temperature are detected to obtain the difference delta T between the two temperatures1Then detecting the outlet water temperature and the inlet water temperature after unit time (which can be set to 60 seconds) to obtain the difference delta T between the outlet water temperature and the inlet water temperature2And if the detected numerical values meet the second preset condition, the unit enters defrosting treatment.
EXAMPLE III
As shown in fig. 3, the present embodiment discloses a flow chart of a defrosting control method for an air energy water heater, which specifically includes:
s31, acquiring dew point temperature T of air in current environment in real timed
S32, dew point temperature TdMeeting a first preset condition;
and S33, controlling the unit to enter defrosting treatment when the unit meets a second preset condition.
In the above technical solution, the obtaining of the dew point temperature T of the air in the current environmentdThe method specifically comprises the following steps:
s311, detecting the dry bulb temperature T of the air in the current environment of the unit in real timeDry ballAnd wet bulb temperature TWet ball
S312, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballAcquiring the relative humidity f of air in the current environment of the unit;
s313, calculating and obtaining the dew point temperature T of the air in the current environment according to the relative humidity fd
Wherein the dew point temperature TdThe calculation method is the same as the above embodiment, and is not described herein again.
Example four
As shown in FIG. 4, the difference between this embodiment and the second embodiment is that when the dew point temperature T is higher than the first embodimentdAnd dry bulb temperature TDry ballWhen a first preset condition is met, the unit does not directly enter defrosting treatment, but enters defrosting treatment only when other judgment conditions are met, and the first preset condition is only the entry condition of unit defrosting.
Specifically, the control method includes:
s41, detecting the dry bulb temperature T of the air in the current environment of the unit in real timeDry ballAnd wet bulb temperature TWet ball
S42, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballObtaining the dew point temperature T of the air in the current environmentd
S43, detecting the evaporation temperature T of the evaporator in real timee
S44, judging whether the dew point temperature Te and the dry bulb temperature T meet a first preset condition or not; if yes, go to step S45, if no, return to step S41;
s45, detecting the change rate P of water temperature T outlet water, water inlet temperature T inlet water and exhaust pressure in real timed
In the embodiment, an outlet water temperature sensor is arranged on the outlet water pipeline, the outlet water temperature sensor is used for detecting the outlet water temperature to obtain T outlet water, an inlet water temperature sensor is arranged on the inlet water pipeline, the inlet water temperature sensor is used for detecting T inlet water according to the inlet water temperature, and the outlet water temperature and the inlet water temperature are used for obtaining the temperature difference delta T between the outlet water temperature and the inlet water temperature; arranging a pressure sensor at the outlet end of the compressor, detecting the exhaust pressure of the compressor in real time by using the pressure sensor to obtain the numerical value of the exhaust pressure, and calculating to obtain the change rate P of the exhaust pressured
S46, judging the water outlet temperature TDischarging waterTemperature T of inlet waterInflow waterAnd the exhaust pressure change rate PdWhether a second preset condition is satisfied, if yes, go to step S47: controlling the unit to enter defrosting treatment; if not, return is made to step S42.
The second predetermined condition being a rate of change of exhaust pressure PdThe temperature is continuously three times larger than a first preset value, and the difference delta T between the current water outlet temperature and the current water inlet temperature1< delta T difference between the water outlet temperature at the previous unit time and the water inlet temperature at the previous unit time2. The first predetermined value is obtained according to a plurality of tests and is stored in the water heater in advance.
Specifically, the pressure sensor is used to detect the discharge pressure change rate of the discharge port of the compressor in unit time (which may be 60 seconds), that is, the current discharge pressure value is detected first, then the discharge pressure after 60 seconds is detected, and the discharge pressure change rate P can be obtained by subtracting the two discharge pressures and then dividing by 60 secondsd. Meanwhile, the current water outlet temperature and the current water inlet temperature are detected to obtain the difference delta T between the two temperatures1Then detecting the outlet water temperature and the inlet water temperature after unit time (which can be set to 60 seconds) to obtain the difference delta T between the outlet water temperature and the inlet water temperature2And if the detected numerical values meet the second preset condition, the unit enters defrosting treatment.
EXAMPLE five
The present embodiment is further defined by the first embodiment, in which the defrosting control method for the air energy water heater further includes: when the unit enters a defrosting treatment process and meets any one of the following two conditions, controlling the unit to exit defrosting;
the first condition is that: defrosting temperature T detected continuously for first preset timeDefrosting creamNot lower than a second predetermined value;
the second condition is that: and the continuous defrosting operation time reaches the set time.
The first preset time is preset time of the water heater, for example, 5 seconds or 10 seconds, and the first preset time is set as required. The second predetermined value is in the range of [10 deg.C, 20 deg.C ]]In this embodiment, it is preferable that the second predetermined value is 15 ℃. I.e. frost melting temperature T is detected for 5 seconds continuouslyDefrosting creamAnd if the temperature is not lower than 15 ℃, controlling the unit to quit defrosting.
Or, the unit is controlled to quit defrosting when the defrosting treatment is continuously carried out for the set time. The set time is preset trigger time, in this embodiment, the set time is 8 minutes, that is, after the unit continuously defrosts for 8 minutes, the unit automatically exits defrosting operation and performs normal heating operation.
EXAMPLE six
As shown in fig. 5, which is a structural diagram of the air-source water heater in the embodiment, the air-source water heater includes a compressor 1, a pressure sensor 2, a condenser 3, a throttling element 4, a dry bulb temperature sensor 5, an outlet water temperature sensor 6, an inlet water temperature sensor 7, a coil temperature sensor 8, an evaporator 9, a wet bulb temperature sensor 10, and a fan 11. Wherein, the outlet water temperature sensor 6 and the inlet water temperature sensor 7 are respectively arranged at the outlet of the water outlet pipeline and the inlet of the water inlet pipeline, the dry bulb temperature sensor 5 and the wet bulb temperature sensor 10 are arranged at the position of the air inlet end of the evaporator 9, the pressure sensor 2 is arranged at the exhaust port of the compressor 1, and the coil pipe temperature sensor 8 is arranged on the evaporator 9.
As shown in fig. 6, the embodiment of the invention discloses a defrosting control system of an air energy water heater, which comprises:
a dew point temperature obtaining module 200 for obtaining the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballObtaining the dew point temperature T of the air in the current environmentd
The dew point temperature obtaining module 200 can obtain the dew point temperature of the present embodiment according to the corresponding calculation formula by the dry bulb temperature and the wet bulb temperature detected by the dry bulb temperature sensor 5 and the wet bulb temperature detected by the wet bulb temperature sensor 10.
A first control module 300 for determining the dew point temperature TdAnd when the first preset condition is met, controlling the unit to perform defrosting treatment.
A sensor module 100, the sensor module 100 comprising: for detecting the temperature T of the dry bulbDry ballDry bulb temperature sensor 5 for detecting wet bulb temperature TWet ballA wet bulb temperature sensor 10, a pressure sensor 2 for detecting the discharge pressure at the outlet end of the compressor, an outlet water temperature sensor 6 for detecting the outlet water temperature in the outlet water pipeline, an inlet water temperature sensor 7 for detecting the inlet water temperature in the inlet water pipeline, and a coil temperature sensor 8 for detecting the evaporation temperature of the evaporator.
The second control module 400 is used for meeting any one of the following conditions after the first control module controls the unit to defrost, and controlling the unit to exit defrosting;
the first condition is that: defrosting temperature T detected continuously for first preset timeDefrosting creamNot lower than a second predetermined value;
the second condition is that: and the continuous defrosting operation time reaches the set time.
The first preset time is preset time of the water heater, for example, 5 seconds or 10 seconds, and the first preset time is set as required. The second predetermined value is in the range of [10 deg.C, 20 deg.C ]]In this embodiment, it is preferable that the second predetermined value is 15 ℃. I.e. frost melting temperature T is detected for 5 seconds continuouslyDefrosting creamAnd if the temperature is not lower than 15 ℃, controlling the unit to quit defrosting.
Or, the unit is controlled to quit defrosting when the defrosting treatment is continuously carried out for the set time. The set time is preset trigger time, in this embodiment, the set time is 8 minutes, that is, after the unit continuously defrosts for 8 minutes, the unit automatically exits defrosting operation and performs normal heating operation.
According to the invention, the dry bulb and wet bulb temperature detection module is arranged on the evaporator, the dry bulb temperature and the wet bulb temperature are detected, the dew point temperature of the current environment is obtained according to the dry bulb temperature and the wet bulb temperature, the unit is controlled to carry out defrosting treatment by taking the dew point temperature meeting the first preset condition as a reference, and the influence of the environment humidity on frosting and defrosting is fully considered, so that unnecessary defrosting treatment is avoided, the waste of resources is reduced, meanwhile, a defrosting program can be entered at a relatively reasonable time node, the reliability of defrosting is also improved, the unit defrosting can be controlled more accurately, and the heating effect is improved.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (5)

1. A defrosting control method for an air energy water heater is characterized by comprising the following steps:
s21, detecting the dry bulb temperature T of the air in the current environment of the unit in real timeDry ballAnd wet bulb temperature TWet ball
S22, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballAcquiring the dew point temperature Td of air in the current environment;
s23, dew point temperature Td and dry bulb temperature TDry ballWhen a first preset condition is met, controlling the unit to enter defrosting treatment;
a dry bulb temperature detection module and a wet bulb temperature detection module are arranged on the air inlet end of the evaporator;
before step S23, the method further includes: detecting the evaporation temperature Te of the evaporator through a coil temperature sensor;
in step S23, the first preset condition is: evaporation temperature Te is less than or equal to dew point temperature Td, and dry bulb temperature TDry ball< a first preset temperature;
in step S23, the dew point temperature Td and the dry bulb temperature TDry ballWhen the first preset condition is not met, the following steps are carried out:
s24 real-time detection of water temperature TDischarging waterTemperature T of inlet waterInflow waterAnd the exhaust pressure change rate Pd, and calculating the difference delta T between the water outlet temperature and the water inlet temperature at the same time;
s25, judging the water outlet temperature TDischarging waterTemperature T of inlet waterInflow waterAnd whether the exhaust pressure change rate Pd meets a second preset condition or not, if so, controlling the unit to carry out defrosting treatment; if not, returning to step S21;
the second preset condition is as follows: the change rate Pd of the exhaust pressure is continuously greater than a first preset value for three times, and the difference delta T1 between the current water outlet temperature and the current water inlet temperature is less than the difference delta T2 between the water outlet temperature in the previous unit time and the water inlet temperature in the previous unit time.
2. A defrosting control method of an air energy water heater is characterized by comprising the following steps: in the working process of a unit, acquiring the dew point temperature Td of air in the current environment in real time; on the premise that the dew point temperature Td meets a first preset condition, and when the unit meets a second preset condition, controlling the unit to enter defrosting treatment;
the first preset condition is as follows: evaporation temperature Te is less than or equal to dew point temperature Td, and dry bulb temperature TDry ball< a first preset temperature;
the second preset condition is as follows: the change rate Pd of the exhaust pressure is continuously greater than a first preset value for three times, and the difference delta T1 between the current water outlet temperature and the current water inlet temperature is less than the difference delta T2 between the water outlet temperature in the previous unit time and the water inlet temperature in the previous unit time; the evaporation temperature Te is detected by a coil pipe temperature sensor of the evaporator, the exhaust pressure change rate Pd is detected by a pressure sensor at the outlet end of the compressor, the outlet water temperature is detected by an outlet water temperature sensor of the water outlet pipeline, and the inlet water temperature is detected by an inlet water temperature sensor of the water inlet pipeline.
3. The defrosting control method of an air energy water heater according to claim 2, wherein the step of obtaining the dew point temperature Td of the air in the current environment specifically comprises the following steps:
s311, detecting the dry bulb temperature T of the air in the current environment of the unit in real timeDry ballAnd wet bulb temperature TWet ball
S312, according to the dry bulb temperature TDry ballAnd wet bulb temperature TWet ballAcquiring the relative humidity f of air in the current environment of the unit;
and S313, calculating the dew point temperature Td of the air in the current environment according to the relative humidity f.
4. An air energy water heater defrosting control method according to any one of claims 2 to 3, characterized by further comprising:
the unit is controlled to quit defrosting when any one of the following conditions is met:
defrosting temperature T detected continuously for first preset timeDefrosting creamNot lower than a second predetermined value; and the continuous defrosting operation time reaches the set time.
5. An air energy water heater defrosting control system, characterized in that the defrosting control method of the air energy water heater according to any one of claims 1 to 4 is adopted, and the defrosting control method comprises the following steps:
a dew point temperature acquisition module for acquiring the temperature T of the dry bulbDry ballAnd wet bulb temperature TWet ballAcquiring the dew point temperature Td of air in the current environment;
a first control module and/or a second control module;
the first control module is used for controlling the unit to carry out defrosting treatment when the dew point temperature Td meets a first preset condition;
a sensor module, the sensor module comprising: for detecting the temperature T of the dry bulbDry ballDry bulb temperature sensor for detecting wet bulb temperature TWet ballThe wet bulb temperature sensor, the pressure sensor used for detecting the exhaust pressure on the outlet end of the compressor, the water outlet temperature sensor used for detecting the water outlet temperature in the water outlet pipeline, the water inlet temperature sensor used for detecting the water inlet temperature in the water inlet pipeline and the coil pipe temperature sensor used for detecting the evaporation temperature of the evaporator;
the second control module is used for meeting any one of the following conditions after the first control module controls the unit to defrost, and controlling the unit to quit defrosting: defrosting temperature T detected continuously for first preset timeDefrosting creamNot lower than a second predetermined value; and the continuous defrosting operation time reaches the set time.
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CN110762756B (en) * 2019-11-01 2021-11-30 宁波奥克斯电气股份有限公司 Air conditioning system and air conditioning frosting control method
CN111947357A (en) * 2020-07-17 2020-11-17 青岛海尔新能源电器有限公司 Temperature adjusting method and water heater
CN112066610A (en) * 2020-10-10 2020-12-11 昆山台佳机电有限公司 Defrosting control system of air source heat pump unit
CN112665119B (en) * 2021-02-02 2022-03-25 南通华信中央空调有限公司 Defrosting control method for direct expansion type air conditioner

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