CN113757908A - Thermal characteristic measuring method and system of air conditioning system, terminal and storage medium - Google Patents

Thermal characteristic measuring method and system of air conditioning system, terminal and storage medium Download PDF

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Publication number
CN113757908A
CN113757908A CN202111148688.4A CN202111148688A CN113757908A CN 113757908 A CN113757908 A CN 113757908A CN 202111148688 A CN202111148688 A CN 202111148688A CN 113757908 A CN113757908 A CN 113757908A
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temperature
water
average temperature
coil
pipeline
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CN113757908B (en
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化振谦
杨雨瑶
潘峰
黄友朋
宋睿
叶佑春
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Guangdong Power Grid Co Ltd
Measurement Center of Guangdong Power Grid Co Ltd
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Guangdong Power Grid Co Ltd
Measurement Center of Guangdong Power Grid Co Ltd
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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
    • 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
    • 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
    • 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
    • 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
    • F24F11/88—Electrical aspects, e.g. circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/02—Ducting arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2110/00—Control inputs relating to air properties
    • F24F2110/10—Temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2140/00—Control inputs relating to system states
    • F24F2140/20—Heat-exchange fluid temperature
    • 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

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Thermal Sciences (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

The invention provides a thermal characteristic measuring method, a system, a terminal and a storage medium of an air conditioning system, wherein the air conditioning system comprises the following components: water chilling units, coils and pipes; the thermal property measurement method includes: acquiring various thermal characteristic initial parameters of the air conditioning system in real time, and acquiring the outlet water temperature of the water chilling unit according to the thermal characteristic initial parameters of the air conditioning system; acquiring the temperature of outlet water of a pipeline according to the temperature of a water outlet of a water chilling unit; acquiring the air supply temperature of the coil according to the temperature of the outlet water of the pipeline; obtaining a thermal characteristic measurement result of the air conditioning system according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of the cold quantity transmitted to the indoor by the air conditioning system after the implementation of the cold machine side control strategy. According to the invention, the measurement results of the water chilling unit, the coil pipe and the pipeline are combined, and compared with the prior art, the method has higher scene applicability and universality, and the measurement method is more effective and faster.

Description

Thermal characteristic measuring method and system of air conditioning system, terminal and storage medium
Technical Field
The invention relates to the field of air conditioning systems, in particular to a thermal characteristic measuring method, system, terminal and storage medium of an air conditioning system.
Background
With the development of science and technology, the requirements of environmental protection and energy conservation are higher and higher in the national policy and social layer at present. In the aspect of an air conditioning system, a tail end control strategy is usually adopted in the prior art to achieve reduction of cooling load during peak air conditioning, so that the response effect of reducing the power consumption demand during peak air conditioning is achieved. These end control strategies essentially take advantage of the thermal characteristics of the building itself to achieve the storage and release of cold to accomplish the transfer of cold load. However, the existing strategies have the technical problems of slow response, monitoring only and no control, simplification or neglecting of the dynamic thermal characteristics of the air conditioning system and the like. Meanwhile, the description of the compressor, the expansion valve and the condenser in the water chilling unit in the prior art is complex, and the generality is not achieved due to the limitation of the form of the cooling side.
Disclosure of Invention
The invention provides a thermal characteristic measuring method, a thermal characteristic measuring system, a thermal characteristic measuring terminal and a storage medium of an air conditioning system, which can quickly measure the dynamic thermal characteristic of the air conditioning system and improve the universality and the multi-scene adaptability.
In order to solve the above technical problem, an embodiment of the present invention provides a thermal characteristic measurement method for an air conditioning system, which is applied to an air conditioning system after a chiller-side control strategy is implemented, and the air conditioning system includes: water chilling units, coils and pipes;
the thermal property measurement method includes:
acquiring initial parameters of thermal characteristics of the air conditioning system in real time; wherein the thermal characteristic initial parameters include: an average temperature of evaporator material within the chiller, an average temperature of refrigerant within the chiller, an average temperature of chilled water within the chiller, an average temperature of piping material, an average temperature of chilled water within the piping, an average temperature of insulation outside the piping, an average temperature of outside air, an outlet water temperature of the coil, and an inlet water temperature of the coil;
acquiring the outlet water temperature of the water chilling unit according to the average temperature of evaporator materials in the water chilling unit, the average temperature of a refrigerant in the water chilling unit and the average temperature of chilled water in the water chilling unit by combining a preset heat exchange coefficient between the refrigerant and the wall surface of the evaporator and a preset heat exchange coefficient between the wall surface of the evaporator and the chilled water;
acquiring the temperature of outlet water of a pipeline according to the temperature of the outlet water of the water chilling unit by combining the average temperature of a pipeline material, the average temperature of chilled water in the pipeline, the average temperature of a heat insulation material outside the pipeline and the average temperature of outside air;
acquiring the air supply temperature of the coil according to the outlet water temperature of the pipeline and by combining a preset saturated enthalpy value of air at the average temperature of the coil, the outlet water temperature of the coil, the inlet water temperature of the coil, the row number of the coil and a preset heat exchange area of water;
obtaining a thermal characteristic measurement result of the air conditioner according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of delivering cold energy to the indoor by the air conditioning system after the cold machine side control strategy is implemented.
Further, the acquiring of the air supply temperature of the coil comprises acquiring the air supply temperature of the coil under a dry working condition and acquiring the air supply temperature of the coil under a wet working condition; the coil pipes are composed of a plurality of rows, and the coil pipes in different rows can be in different dry and wet working conditions.
Further, the obtaining of the initial parameter of the thermal characteristic of the air conditioning system in real time specifically includes: the method comprises the steps of acquiring the average temperature of evaporator materials in a water chilling unit, the average temperature of a refrigerant in the water chilling unit, the average temperature of chilled water in the water chilling unit, the average temperature of pipeline materials, the average temperature of chilled water in a pipeline, the average temperature of heat insulation materials outside the pipeline, the average temperature of outside air, the outlet water temperature of a coil and the inlet water temperature of the coil in real time through a plurality of sensors.
Further, the cold machine side control strategy comprises an intermittent shutdown strategy, a partial cold machine closing strategy and a chilled water temperature increasing strategy; after the thermal characteristic measurement method is applied to the implementation of the control strategy at the cold machine side, a new stable state is formed.
Correspondingly, the embodiment of the invention also provides a thermal characteristic measuring system of the air conditioning system, which comprises an acquisition module, a water chiller module, a pipeline module, a coil pipe module and a thermal characteristic measuring module, wherein the acquisition module is used for acquiring the thermal characteristic of the air conditioning system; wherein the content of the first and second substances,
the acquisition module is used for acquiring the initial parameters of the thermal characteristics of the air conditioning system in real time; wherein the thermal characteristic initial parameters include: an average temperature of evaporator material within the chiller, an average temperature of refrigerant within the chiller, an average temperature of chilled water within the chiller, an average temperature of piping material, an average temperature of chilled water within the piping, an average temperature of insulation outside the piping, an average temperature of outside air, an outlet water temperature of the coil, and an inlet water temperature of the coil;
the water chilling unit module is used for acquiring the outlet water temperature of the water chilling unit according to the average temperature of evaporator materials in the water chilling unit, the average temperature of a refrigerant in the water chilling unit and the average temperature of chilled water in the water chilling unit by combining a preset heat exchange coefficient between the refrigerant and the wall surface of the evaporator and a preset heat exchange coefficient between the wall surface of the evaporator and the chilled water;
the pipeline module is used for acquiring the temperature of outlet water of the pipeline according to the temperature of the outlet water of the water chilling unit by combining the average temperature of a pipeline material, the average temperature of chilled water in the pipeline, the average temperature of a heat insulation material outside the pipeline and the average temperature of outside air;
the coil pipe module is used for acquiring the air supply temperature of the coil pipe according to the outlet water temperature of the pipeline and by combining a preset saturated enthalpy value of air at the average temperature of the coil pipe, the outlet water temperature of the coil pipe, the inlet water temperature of the coil pipe, the row number of the coil pipe and a preset heat exchange area of water;
the thermal characteristic measurement module obtains a thermal characteristic measurement result of the air conditioning system according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of delivering cold energy to the indoor by the air conditioning system after the cold machine side control strategy is implemented.
Further, the acquiring of the air supply temperature of the coil comprises acquiring the air supply temperature of the coil under a dry working condition and acquiring the air supply temperature of the coil under a wet working condition; the coil pipes are composed of a plurality of rows, and the coil pipes in different rows can be in different dry and wet working conditions.
Further, the acquiring module is configured to acquire the initial parameter of the thermal characteristic of the air conditioning system in real time, specifically: the method comprises the steps of acquiring the average temperature of evaporator materials in a water chilling unit, the average temperature of a refrigerant in the water chilling unit, the average temperature of chilled water in the water chilling unit, the average temperature of pipeline materials, the average temperature of chilled water in a pipeline, the average temperature of heat insulation materials outside the pipeline, the average temperature of outside air, the outlet water temperature of a coil and the inlet water temperature of the coil in real time through a plurality of sensors.
Further, the cold machine side control strategy comprises an intermittent shutdown strategy, a partial cold machine closing strategy and a chilled water temperature increasing strategy; and after the thermal characteristic measurement system is applied to the implementation of the cold machine side control strategy, a new stable state is formed.
Correspondingly, the embodiment of the invention also provides a terminal, which comprises a processor, a memory and a computer program stored in the memory; wherein the computer program is executable by the processor to implement the thermal characteristic measurement method of the air conditioning system.
Correspondingly, the embodiment of the invention also provides a computer readable storage medium, wherein the computer readable storage medium comprises a stored computer program; wherein the apparatus in which the computer readable storage medium is located is controlled to perform the thermal characteristic measurement method of the air conditioning system when the computer program is executed.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
the embodiment of the invention provides a thermal characteristic measuring method, a system, a terminal and a storage medium of an air conditioning system, wherein the air conditioning system comprises the following components: water chilling units, coils and pipes; the thermal property measurement method includes: acquiring various thermal characteristic initial parameters of the air conditioning system in real time, and acquiring the outlet water temperature of the water chilling unit according to the thermal characteristic initial parameters of the air conditioning system; acquiring the temperature of outlet water of a pipeline according to the temperature of a water outlet of a water chilling unit; acquiring the air supply temperature of the coil according to the temperature of the outlet water of the pipeline; obtaining a thermal characteristic measurement result of the air conditioning system according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of the cold quantity transmitted to the indoor by the air conditioning system after the implementation of the cold machine side control strategy. According to the invention, the measurement results of the water chilling unit, the coil pipe and the pipeline are combined, and compared with the prior art, the method has higher scene applicability and universality, and the measurement method is more effective and faster.
Drawings
Fig. 1 is a schematic flowchart of an embodiment of a thermal characteristic measurement method of an air conditioning system according to the present invention.
Fig. 2 is a schematic diagram of a technical concept of an embodiment of a thermal characteristic measuring method of an air conditioning system according to the present invention.
Fig. 3 is a simplified frame diagram of the thermal characteristics of the chiller in the thermal characteristic measurement method of the air conditioning system according to the present invention.
Fig. 4 is a schematic diagram of an analyzed pipe section for a pipe in the thermal characteristic measurement method of an air conditioning system according to the present invention.
Fig. 5 is a schematic structural diagram of a thermal characteristic measurement system of an air conditioning system according to an embodiment of the present invention.
Fig. 6 is a schematic diagram of a laboratory configuration for experimental verification in the thermal characteristic measurement method of the air conditioning system according to the present invention.
Fig. 7 is a schematic diagram of a laboratory bench air conditioning system and a test point arrangement for experimental verification in the thermal characteristic measurement method of the air conditioning system according to the embodiment of the present invention.
Fig. 8 is a comparison graph of the outlet water temperature of the water chiller module after the control strategy is implemented in the thermal characteristic measurement system of the air conditioning system according to the embodiment of the present invention and the experimental result.
Fig. 9 is a schematic diagram illustrating the results of verifying the measurement results of the chiller, the coil and the pipeline in the thermal characteristic measurement system of the air conditioning system according to the embodiment of the present invention.
Fig. 10 is a verification result of the overall thermal characteristics of the air conditioning system according to the embodiment of the present invention.
Fig. 11 is a result of verifying the thermal characteristics of a chiller in an office building according to an embodiment of the present invention.
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.
The first embodiment is as follows:
referring to fig. 1, fig. 1 is a diagram illustrating a thermal characteristic measurement method of an air conditioning system according to an embodiment of the present invention, applied to an air conditioning system implemented with a chiller-side control policy, where the air conditioning system includes: water chilling units, coils and pipes;
referring to fig. 2, fig. 2 is a schematic view illustrating a technical concept of an embodiment of a thermal characteristic measuring method of an air conditioning system according to the present invention.
The thermal property measurement method includes steps S1 to S5; wherein the content of the first and second substances,
step S1, acquiring initial parameters of thermal characteristics of the air conditioning system in real time; wherein the thermal characteristic initial parameters include: an average temperature of evaporator material within the chiller, an average temperature of refrigerant within the chiller, an average temperature of chilled water within the chiller, an average temperature of piping material, an average temperature of chilled water within the piping, an average temperature of insulation outside the piping, an average temperature of outside air, an outlet water temperature of the coil, and an inlet water temperature of the coil.
In this embodiment, the obtaining of the initial parameter of the thermal characteristic of the air conditioning system in real time specifically includes: the method comprises the steps of acquiring the average temperature of evaporator materials in a water chilling unit, the average temperature of a refrigerant in the water chilling unit, the average temperature of chilled water in the water chilling unit, the average temperature of pipeline materials, the average temperature of chilled water in a pipeline, the average temperature of heat insulation materials outside the pipeline, the average temperature of outside air, the outlet water temperature of a coil and the inlet water temperature of the coil in real time through a plurality of sensors.
And step S2, acquiring the temperature of outlet water of the water chilling unit according to the average temperature of evaporator materials in the water chilling unit, the average temperature of refrigerant in the water chilling unit and the average temperature of chilled water in the water chilling unit by combining a preset heat exchange coefficient between the refrigerant and the wall surface of the evaporator and a preset heat exchange coefficient between the wall surface of the evaporator and the chilled water.
In this embodiment, fig. 3 is a simplified framework of the thermal characteristics of the chiller, and we first make some simplifications to the chiller, including:
the adjustment of the temperature of the chilled water is completed by the loading and unloading of the compressor, and the delay of the adjustment of the compressor is negligible relative to the thermal characteristics of the air conditioning system; the refrigerant flow throughout the cycle remains constant and the amount of refrigerant in the evaporator and condenser remains constant; the relative flow between the coolant (i.e., chilled water) and the refrigerant can be reduced to pure convection; the chilled water temperature varies linearly along the evaporator and the evaporator shell temperature is described by an average temperature; the mass of the superheated steam fraction, i.e. the stored energy, is negligible; a two-phase flow can be represented by a hypothetical single-phase fluid having average physical parameters.
After the above simplification, the present embodiment focuses on the dynamic change process of the chilled water side at the time of cold regulation, and therefore the modeling process of the cooling water side, the compressor, and the expansion valve can be simplified. The influence of the dynamic changes of the cooling water side, the compressor and the expansion valve on the freezing side is classified as the cold quantity Q of the refrigerantref(t) dynamic variation. Qref(t) shows the dynamic variation of the cooling capacity available from the refrigerant in the evaporator, and describes the cooling capacity delivered to the evaporator shell by the refrigerant in the evaporator. The water chiller module is more universal and is not limited by the form of the cooling side any more.
Common cold machine side demand response strategies typically include intermittent shutdown, partial cold machine shutdown, and chilled water temperature increase. These strategies achieve chiller power reduction by unloading the chiller or reducing chiller cooling load. After the strategy is implemented, the refrigerating capacity Q of the refrigerantrefThe course of change in (t) can be described as Q from steady stateref(t) into dynamic Cooling Qref(t) straightTo a new steady state.
The dynamic heat balance of the refrigerant, the evaporator shell and the chilled water is respectively as follows, and is mainly used for describing the dynamic change of cold quantity transferred from the cold machine to the chilled water after the demand response strategy is implemented and before a new stable state is formed.
Dynamic balance of refrigerant:
Figure BDA0003285405710000071
dynamic balancing of evaporator shell:
Figure BDA0003285405710000072
dynamic equilibrium of chilled water:
Figure BDA0003285405710000073
wherein, the superscript ch represents the parameters related to the chiller (chiller) to distinguish the related parameters of the coil (co, coil) and the pipe (pi, pipe). T iseva、TrefAnd
Figure BDA0003285405710000074
which represents the average temperature of the evaporator material, refrigerant and chilled water within the object under analysis. Alpha is alpharef-evaIs the heat transfer coefficient between the refrigerant and the wall of the evaporator, alphaw-evaIs the heat exchange coefficient between the wall surface of the evaporator and the chilled water. A. thew-evaIs the heat exchange area between the wall surface of the evaporator and the chilled water, Aref-evaThe heat exchange area between the refrigerant and the wall surface of the evaporator. c. Ceva、crefAnd cwWhich represents the specific heat capacity of the evaporator material, refrigerant and chilled water in the chilled water unit. m iseva、mrefAnd mwIndicating the quality of the evaporator material, refrigerant and chilled water in the chilled water unit. QrefAnd (t) is the refrigeration capacity of the refrigerant.
Figure BDA0003285405710000081
The temperature of the supplied water and the returned water of the cold water in the cold machine.
Figure BDA0003285405710000082
The mass flow of the chilled water can be obtained by a cold meter (composed of a temperature sensor and a flow meter) installed in the building.
The heat transfer coefficient can be calculated according to an empirical formula.
Figure BDA0003285405710000083
Figure BDA0003285405710000084
αw-eva＝Nuref-eva·λw/deva (6)
Wherein, C1、C2、n1、n2Is a constant. Nu (Nu)w-evaIs the Nulsert criterion number of the frozen water in the refrigerator. RewIs the reynolds number of the chilled water. Lambda [ alpha ]wIs the coefficient of thermal conductivity of the chilled water. devaThe size of the frozen water pipeline is fixed.
And step S3, acquiring the temperature of the outlet water of the pipeline according to the temperature of the outlet water of the water chilling unit and by combining the average temperature of the pipeline material, the average temperature of the chilled water in the pipeline, the average temperature of the heat insulation material outside the pipeline and the average temperature of the outside air.
In this embodiment, the description of the conduit includes three sections: chilled water inside the pipeline, pipeline material and insulation material outside the pipeline. Also, the piping is first simplified:
assuming that the heat capacity of the external insulation material is negligible, the insulation material outside the pipeline can be described in a steady state; all distribution pipelines are divided into a plurality of pipe sections, and the temperature of the refrigerated water and the pipe in the cross section direction of the analyzed pipe section is assumed to be uniformly distributed, and the temperature in the length direction is linearly changed.
FIG. 4 is a schematic view of a pipe segment being analyzed. The inlet water temperature of each pipeline section is the outlet water temperature of the previous pipeline section or equipment, and the outlet water temperature of the pipeline section is the inlet water temperature of the next pipeline section or equipment. The chilled water dynamic heat balance equation:
Figure BDA0003285405710000085
neglecting the heat capacity of the thermal insulation material, that is, the heat transfer of the thermal insulation material is processed according to the steady state heat transfer, so the heat exchange quantity between the outer side of the thermal insulation material and the air is equal to the heat exchange quantity between the inner side of the thermal insulation material and the outer wall of the pipe, therefore, the following can be obtained:
Figure BDA0003285405710000091
there is also a dynamic thermal equilibrium of the pipe material:
Figure BDA0003285405710000092
wherein, Tpi、
Figure BDA0003285405710000093
TinsAnd
Figure BDA0003285405710000094
respectively the average temperature of the pipeline material, the internal chilled water, the external heat preservation and the outside air in the analyzed pipe section.
Figure BDA0003285405710000095
The temperature of the supplied and returned water of the refrigerated water of the analyzed pipe section. Alpha is alphaw-piThe heat transfer coefficient of the chilled water and the pipeline. Alpha is alphapi-insIs the heat exchange coefficient between the pipeline and the inner side of the heat insulation material. Alpha is alphaα-insThe heat exchange coefficient between the outside ambient air outside the heat insulation material. A. thew-piThe heat exchange area of the chilled water and the pipeline. A. thepi-insIs the heat exchange area between the pipeline and the inner side of the heat insulation material. A. theα-insThe heat exchange area between the outer side of the heat insulation material and the air of the external environment. c. CpiIs the specific heat capacity of the pipeline. m ispiIs the pipe mass.
Heat transfer coefficient alpha between chilled water and pipelinew-piAnd the heat exchange coefficient alpha between the outside of the heat insulating material and the outside ambient airα-insCan be obtained from empirical formulas:
αw-pi＝Nuw-pi·λw/dpi (10)
Figure BDA0003285405710000096
αα-ins＝Nuα-ins·λα/dins (12)
Figure BDA0003285405710000097
wherein, C6、C7、n6～n8Is a constant. Nu (Nu)w-piIs the Nursery criterion number of the frozen water in the pipeline. Nu (Nu)α-insThe nuschelt criterion number for the air outside the duct. Lambda [ alpha ]αIs the air thermal conductivity. dpiIs the inner diameter of the pipe of the analyzed pipe section. dinsIs the outside diameter of the pipe. Gr is Gr Gratawner number. Pr is the Plantt criterion number for the pipeline.
And step S4, acquiring the air supply temperature of the coil according to the outlet water temperature of the pipeline and by combining a preset saturated enthalpy value of air at the average temperature of the coil, the outlet water temperature of the coil, the inlet water temperature of the coil, the row number of the coil and a preset heat exchange area of water.
In this embodiment, the acquiring the air supply temperature of the coil includes acquiring the air supply temperature of the coil under a dry condition and acquiring the air supply temperature of the coil under a wet condition; the coil pipes are composed of a plurality of rows, and the coil pipes in different rows can be in different dry and wet working conditions.
In this embodiment, too, a certain simplification of the coil is made:
air heat storage is not considered; when dehumidification occurs, the influence of residual chilled water on the fins and the pipeline is ignored; the temperature distribution inside the fins and in the height direction of the fins conforms to the steady-state characteristics, so the heat and mass transfer processes of the fins can be described by using the fin efficiency; the relative flow between chilled water and air is described in terms of pure convection.
The coil is made up of multiple rows, any one row of the coil being in a fully dry or fully wet state for each time step, while different rows may be in different dry and wet states for separate calculations.
Dynamic thermal equilibrium of coil material:
Figure BDA0003285405710000101
dynamic thermal equilibrium of chilled water under dry conditions:
Figure BDA0003285405710000102
dynamic heat balance of chilled water in wet conditions:
Figure BDA0003285405710000103
wherein, Tco、
Figure BDA0003285405710000104
And
Figure BDA0003285405710000105
the coil material, the air outside the coil and the average temperature of the frozen water inside the coil are respectively.
Figure BDA0003285405710000106
And
Figure BDA0003285405710000107
the water temperature is the inlet and outlet water temperature of the coil pipe. h iss,coIndicating the average temperature T of the air in the coilcoLower saturation enthalpy value.
Figure BDA0003285405710000108
The enthalpy value of the air outside the coil pipe under the wet working condition. RαThermal resistance is transferred to the air side of each row of coils. R'αThe total thermal resistance of heat and mass transfer between the coil material and the air. RwA thermal transfer resistance for the water side of each row of coils. c. CcoIs the specific heat capacity of the coil material. m iscoIs the quality of the coil material.
In the simplification of the coil, the mutual flow between air and water is simplified into a pure convection form, and the thermal resistance on each water discharging side of the coil can be expressed as:
Figure BDA0003285405710000111
wherein A isw-co,totIs the total heat exchange area, alpha, of the water sidew-coThe heat exchange coefficient between the chilled water and the coil pipe is shown, and N is the number of rows.
Air side heat transfer resistance R of each row of coil pipesα：
Figure BDA0003285405710000112
Wherein, cαIs the specific heat capacity of the air,
Figure BDA0003285405710000113
for mass flow of air,. epsilonαThe "efficiency" of each row of heat exchange of the air side coil can be calculated by the following formula:
Figure BDA0003285405710000114
wherein each timeNumber of heat transfer units NTU in a rowα：
Figure BDA0003285405710000115
Wherein eta isαFor the heat exchange efficiency of each row of coils on the air side, alphaα-coFor each row of heat transfer coefficient on the air side, Aα-co,totIs the air side heat exchange area.
Total heat and mass transfer thermal resistance R 'between coil material and air'α：
Figure BDA0003285405710000116
Wherein epsilon'αThe total efficiency of the air-side heat and mass transfer can be calculated by the following formula:
Figure BDA0003285405710000117
Figure BDA0003285405710000118
wherein, NTu'αIs total heat transfer unit number of coil pipe, eta'αIs the total heat exchange efficiency of the air side coil pipe, alpha'α-coThe total heat exchange coefficient of the air side, in order to determine the above parameters, three groups of parameters need to be further determined: alpha is alphaw-coAw-co,tot、ηααα-coAα-co,totAnd η'αα′α-coAα-co,tot. These three sets of parameters can be obtained from empirical formulas:
Figure BDA0003285405710000121
Figure BDA0003285405710000122
Figure BDA0003285405710000123
wherein, C5＝C4，n5＝n4，C3～C5、n3～n5Constant, can be obtained from the short term operational data of the coil by non-linear regression.
Figure BDA0003285405710000124
In order to obtain the mass flow of the chilled water,
Figure BDA0003285405710000125
is the air side mass flow. Therefore, before a coil uses the module, a period of running records are needed, and detailed geometric description information and other parameters of the coil are not needed. For coils that have been put into operation (coils in demand response), detailed factory information and geometric descriptions are difficult to obtain, but operational parameters can be obtained through short-term testing.
Step S5, obtaining the thermal characteristic measurement result of the air conditioning system according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of delivering cold energy to the indoor by the air conditioning system after the cold machine side control strategy is implemented.
In this embodiment, the chiller side control strategy includes an intermittent shutdown strategy, a partial chiller shutdown strategy, and a chilled water temperature increase strategy; after the thermal characteristic measurement method is applied to the implementation of the control strategy at the cold machine side, a new stable state is formed.
Correspondingly, referring to fig. 5, fig. 5 is a thermal characteristic measurement system of an air conditioning system according to an embodiment of the present invention, which includes an obtaining module 101, a water chiller module 102, a pipeline module 103, a coil module 104, and a thermal characteristic measurement module 105; wherein the content of the first and second substances,
the obtaining module 101 is configured to obtain an initial parameter of a thermal characteristic of the air conditioning system in real time; wherein the thermal characteristic initial parameters include: an average temperature of evaporator material within the chiller, an average temperature of refrigerant within the chiller, an average temperature of chilled water within the chiller, an average temperature of piping material, an average temperature of chilled water within the piping, an average temperature of insulation outside the piping, an average temperature of outside air, an outlet water temperature of the coil, and an inlet water temperature of the coil.
In this embodiment, the obtaining module 101 is configured to obtain the initial parameter of the thermal characteristic of the air conditioning system in real time, specifically: the method comprises the steps of acquiring the average temperature of evaporator materials in a water chilling unit, the average temperature of a refrigerant in the water chilling unit, the average temperature of chilled water in the water chilling unit, the average temperature of pipeline materials, the average temperature of chilled water in a pipeline, the average temperature of heat insulation materials outside the pipeline, the average temperature of outside air, the outlet water temperature of a coil and the inlet water temperature of the coil in real time through a plurality of sensors.
The water chilling unit module 102 is configured to obtain an outlet water temperature of the water chilling unit according to an average temperature of an evaporator material in the water chilling unit, an average temperature of a refrigerant in the water chilling unit, and an average temperature of chilled water in the water chilling unit, in combination with a preset heat exchange coefficient between the refrigerant and a wall surface of the evaporator, and a preset heat exchange coefficient between the wall surface of the evaporator and the chilled water.
The pipeline module 103 is used for acquiring the temperature of outlet water of the pipeline according to the temperature of the outlet water of the water chilling unit by combining the average temperature of a pipeline material, the average temperature of chilled water in the pipeline, the average temperature of a heat insulation material outside the pipeline and the average temperature of outside air.
The coil module 104 is configured to obtain an air supply temperature of the coil according to an outlet water temperature of the pipeline, in combination with a preset saturated enthalpy value of air at the average temperature of the coil, an outlet water temperature of the coil, an inlet water temperature of the coil, a number of rows of the coil, and a preset heat exchange area of water.
In this embodiment, the acquiring the air supply temperature of the coil includes acquiring the air supply temperature of the coil under a dry condition and acquiring the air supply temperature of the coil under a wet condition; the coil pipes are composed of a plurality of rows, and the coil pipes in different rows can be in different dry and wet working conditions.
The thermal characteristic measurement module 105 is configured to obtain a thermal characteristic measurement result of the air conditioning system according to a temperature of an outlet water of the chiller, a temperature of an outlet water of the pipeline, and an air supply temperature of the coil; and the thermal characteristic measurement result is a dynamic change process of delivering cold energy to the indoor by the air conditioning system after the cold machine side control strategy is implemented.
In this embodiment, the chiller side control strategy includes an intermittent shutdown strategy, a partial chiller shutdown strategy, and a chilled water temperature increase strategy; after the thermal characteristic measurement method is applied to the implementation of the control strategy at the cold machine side, a new stable state is formed.
Correspondingly, the embodiment of the invention also carries out experimental verification on the thermal characteristic measurement method of the air conditioning system.
First, common cold-side demand response control strategies fall into two broad categories:
starting and stopping control: this type of control strategy ensures a continuous supply of cold to the room by shutting down (part or all) the chiller while keeping the other equipment on the chilled water side running continuously to take advantage of the cold stored in the chilled water and the equipment materials. Shutdown of some or all chillers, intermittent shutdown are all such control strategies.
Controlling the temperature of the refrigerating water: the control strategy is to increase the efficiency of the cooler and reduce the cooling load of the cooler by increasing the temperature of the chilled water, thereby realizing the reduction of the power consumption of the air conditioner. Mainly means 'increasing the set value of the chilled water temperature', and can be realized by resetting the return water temperature or the water supply temperature.
Therefore, the two types of control strategies are verified in the following experiment to determine the dynamic change rule of the refrigeration capacity of the refrigerant after different demand response control strategies are implemented.
The thermal characteristics of the chilled water side of the air conditioning system consist of the thermal characteristics of the chiller, the thermal characteristics of the coils, and the thermal characteristics of the piping.
Wherein the chiller module 102 focuses on the dynamic heat transfer characteristics of the chilled water side, i.e., the evaporator side, and attributes the dynamic changes of the other components (condenser, compressor, and expansion valve) to changes in the cooling capacity of the refrigerant in the evaporator, denoted by Qref(t) represents. And the cold quantity change rule of the refrigerant after different demand response control strategies are implemented needs to be obtained and verified through experiments.
In experimental studies of the thermal behavior of air conditioning systems, therefore, first of all, the refrigerant cooling curve of the control strategy under study is determined experimentally by means of a "training set". Two types of basic strategies at the cold machine side are selected for carrying out experimental solution, namely strategy type 1-start and stop control and strategy type 2-chilled water temperature control.
Then, the cold water unit and the cold quantity Q of the refrigerant are respectively verified through a verification group experimentref(t), accuracy of coil, pipe, and overall thermal characterization. Root Mean Square Error (RMSE) was taken for evaluation.
Figure BDA0003285405710000141
And finally, verifying the refrigerating capacity of the refrigerant under different control strategies again through a water chiller module in a certain practical office building. The change rule of the refrigerating capacity of the refrigerating agent obtained by the experiment table is proved to have certain universality. The chiller module 102, coil module 104 and pipe module 103 are solved by discrete equations using MATLAB programming. The discrete form used for numerical solution is shown in table 1.
TABLE 1 discrete modes of thermal behavior for air conditioning systems
Figure BDA0003285405710000151
The experimental air conditioning system is located on a building total efficiency test platform (as shown in fig. 6, fig. 6 is a schematic diagram of a laboratory structure for experimental verification), and the whole experiment table consists of two identical rooms and an environmental control cabin. The environment control cabin and the room are provided with two sets of completely independent air conditioning systems which are respectively used for controlling the indoor temperature in the room and the outdoor environment of the room. During the experiment, the air conditioning system of the room external environment experiment cabin is started, so that the external environment of the test room is basically in a stable state, namely, the external disturbance is constant. The test chamber is in an idle state, and no internal disturbance of personnel, equipment and the like exists, namely the internal disturbance of the test chamber is constant and zero. Therefore, the indoor temperature change of the room is mainly influenced by the change of the cooling capacity of the air conditioner, and the stable operation of the air conditioning system in the non-adjusting time period is ensured.
During the experiment, only the air conditioning terminal of one room was turned on, and the air conditioning terminal of the other room was in a normally closed state. For a single room, the construction schematic diagram of the system and the arrangement of the main measuring points in the experiment are shown in fig. 7 (fig. 7 is the schematic diagram of the air conditioning system and the arrangement of the measuring points of the experiment table), and the measuring point list is shown in table 2.
TABLE 2 air-conditioning system experiment table measuring point list
Figure BDA0003285405710000161
Sensor naming rules: "S" -sensor, "1 to 8" -number, "T" -temperature, "M" -flow, "TH" -temperature and humidity.
The detailed parameters of the chiller, coil and distribution piping in the bench are shown in table 3. The parameters appearing in formulas (4) to (6), (10) to (13) and (24) to (26) can be obtained by non-linear regression from short-term experimental test data. Therefore, before the formal experiment, the unit operation parameters under different working conditions are obtained through short-term test, and the obtained constants are shown in table 4.
TABLE 3 detailed parameters of each equipment of air conditioning system laboratory bench
Figure BDA0003285405710000162
Figure BDA0003285405710000171
Table 4 values of constants in experimental air conditioning system
C1 2896 C5 ＝C4 n1 －0.2 n5 ＝n4
C2 3942 C6 0.023 n2 0.2 n6 0.8
C3 8.6 C7 0.1 n3 0.90 n7 0.3
C4 4.2 n4 0.85 n8 0.33
As noted above, the present study has conducted experimental studies on two general classes of cold side control strategies. Details of the individual control strategies in the bench validation are shown in table 5.
TABLE 5 details of control strategies in the experiment
Figure BDA0003285405710000172
Two types of common cold machine side strategies are researched in the experiment, so that the cold quantity Q of the refrigerant after the two control strategies are implemented is determinedref(t) dynamic variation.
Refrigerating capacity Q of refrigerantref(t) solving:
the experiments under each control strategy are divided into two groups, wherein the training group is used for solving the refrigerating capacity of the refrigerating agent, and the verification group is used for verifying the refrigerating capacity of the refrigerating agent and the accuracy of the overall thermal characteristics of the water chilling unit, the coil pipe, the pipeline and the air conditioning system. The following first describes the refrigerant cold solving situation of the training set.
Wherein, start and stop the control strategy:
in the 'start-stop control' experiment, after the air conditioning system runs for a period of time and reaches stable operation, the cold machine is closed, and meanwhile, the chilled water pump and the tail end are kept running continuously and the running parameters are unchanged. Therefore, the cold quantity retained in the evaporator, the chilled water and the materials of all parts can still play a certain refrigeration effect, thereby delaying the indoor temperature rise.
After the unit shutdown strategy is implemented, the whole unit has certain regulation delay and heat transfer delay, so whether the refrigerating capacity of the refrigerating fluid can be directly regarded as zero after the unit is shutdown needs to be further verified through experiments. If the influence of the adjustment delay is negligible, the refrigerating capacity of the unit is immediately reduced to zero after the refrigerator is closed, and the refrigerating capacity of the refrigerant in the evaporator should be zero. Adopting trial calculation method to make QrefAnd (t) substituting 0 into the thermal characteristics of the water chilling unit after the cold machine control strategy is implemented, and verifying the assumed reasonability by comparing with an experimental result.
And taking the operation parameters of the stable operation state before the cold machine is closed as the initial state parameters of the whole system dynamic solution. The dynamic process after the chiller is shut down is as in equations (1) to (3), and the discrete form for numerical solution is as in equations (28) to (30). The result of the first time step is used as the initial parameter of the second time step in the calculation, and so on. The chiller module 102 needs to accurately predict the change of the water outlet parameters when the water inlet state parameters change. Because the flow of the freezing water in the experiment is not adjusted, the temperature of the outlet water of the water chilling unit is selected as a verification parameter.
Will QrefThe outlet water temperature of the chilled water measured with (t) set to zero was compared with the experimental test results, as shown in fig. 8 (a). The outlet water temperature of the chilled water of the cooler gradually rises after the cooler is closed, and the water temperature is still lower than the indoor air temperature after 20 minutes and is about 14 ℃, which shows that the whole air conditioning system still has certain refrigerating capacity at the moment. As can be seen from fig. 8(a), the outlet water temperature obtained by the water chilling unit under the measurement method of the present embodiment matches the variation trend of the experimental result, and the water chilling unit is according to the heat characteristicsThe root mean square error RMSE between the results obtained by the sex measurement method and the experimental results was 0.21 ℃. This shows that the cooling capacity Q of the refrigerant after the cold machine is turned offrefThe assumption that (t) is set directly to zero is reasonable and the chiller module 102 can accurately describe the dynamic changes in chilled water temperature.
Chilled water temperature control strategy:
in practical buildings, raising the chilled water temperature set value is also a common cold machine side demand response control strategy. The cold machine of the experiment table can reset the return water temperature of the chilled water, the return water temperature of the chilled water in the experiment is adjusted to 14 ℃ from 12 ℃ during initial stable operation, and other operation parameters are kept unchanged.
Likewise, the amount of refrigerant cooling Q in chiller modules 102(1) through (3)ref(t) is an unknown parameter. Usually, for a new control strategy, the operating parameters in the module can be measured experimentally, at which point the refrigerant cooling Q isref(t) as the only unknown parameter in the module, can be obtained by reverse extrapolation of experimental results. However, it was found in the experiment that the temperature rising speed of the chilled water after the temperature is reset and before the set water temperature reaches the new set return water temperature is very close to the temperature rising speed of the chilled water after the unit is shut down, as shown in fig. 8 (b). Therefore, it is assumed that the cooling capacity Q of the refrigerant is equal to or higher than the preset value after the temperature of the chilled water is resetref(t) may still be considered zero. The chilled water temperature reset module measures the chiller outlet water temperature as shown in fig. 8 (c). The outlet water temperature measured by the module is similar to the change trend of the experimental result, and the root mean square error RMSE of the module measurement result and the experimental result is 0.23 ℃. This means that after the chilled water temperature is raised, the chiller will be in a temporary shutdown state for a certain period of time due to the reduced load. The chilled water temperature can be reset and the refrigerant cold can be set to zero until the new temperature set point is reached.
In addition, the water chilling unit is verified based on a thermal characteristic measurement method:
the verification of the measurement result of the thermal characteristic of the water chilling unit comprises two purposes, namely the verification of the accuracy of the refrigerating capacity c of the refrigerating fluid under two control strategies and the verification of the accuracy of equation sets (1) to (3) of the water chilling unit. The initial parameters of the water chilling unit are the parameters of the stable operation state before the implementation of the response strategy, comprise the temperature, the flow and the like of the supply and return water of the chilled water, and can be obtained by sensors S1-T, S2-M and S5-T. During the module dynamic process, the accuracy of the water chiller module 102 is verified using the supply water temperature (S1-T).
The verification results of the modules are shown in fig. 9(a) (b). Under the two control strategies, the water supply temperature measured by the water chilling unit module is consistent with the variation trend of the experimental result. For the strategy of closing the cold machine, the root mean square error RMSE of the measurement result and the experimental result of the cold water machine set is 0.39 ℃; for increasing chilled water temperatures, the root mean square error RMSE between the chiller module measurements and the experimental results was 0.38 ℃. Therefore, the method for measuring the thermal characteristics of the water chilling unit can accurately predict the dynamic change process of the chilled water temperature at the cold machine side after the implementation of the demand response strategy to a certain extent, and the obtained cold quantity of the refrigerant in the dynamic process is reasonable.
The accuracy of the cold water unit and the cold energy of the refrigerant and the applicability of the cold water unit and the cold energy of the refrigerant in the actual cold water unit are verified again through the test of the actual building cold water unit.
Verification of coil module 104 measurements:
the state parameters in steady operation serve as initial conditions for the measurement of the coil modules (14) to (16). The state parameters required for module validation may be measured by sensors S3-T, S4-T, S6-TH, S7-M, and S8-T. The temperature and humidity of indoor air are used as state parameters of return air temperature. Because the air volume of the fan coil pipe is kept unchanged in the experiment
Figure BDA0003285405710000201
The supply air temperature (S8-T) therefore directly reflects the amount of cooling delivered to the room air by the fan coil, where it is selected as the output parameter for verification by the coil module 104.
The verification results of the modules are shown in fig. 9(c) and (d), and the variation trends of the module-measured air supply temperature and the experimental-tested air supply temperature are basically consistent. The accuracy of the module was evaluated by the root mean square error of the module measurements versus the experimental results, with the root mean square error RMSE of the two strategies being 0.31 ℃ and 0.28 ℃ respectively. As can be seen from the module verification results, the coil module can accurately predict the dynamic change process of the air supply temperature after the response strategy is implemented.
Verification of the pipe module 103 measurement:
the initial state parameters of the pipeline module 103 when equations (7) (9) verify are the steady state operating state parameters before the response strategy is implemented. The parameters required for pipeline verification are measured by sensors S1-T, S2-M and S3-T. Because the flow of chilled water is not adjusted in the experiment, the pipeline module 103 should be able to accurately describe the changing process of the outlet water temperature of the pipeline when the inlet water temperature of the pipeline is dynamically changed. According to the comparison results of the experiment and the module, the root mean square error RMSE of the outlet water temperature predicted by the pipeline module under the two control strategies relative to the experimental collected water temperature is 0.27 ℃ and 0.34 ℃. It can also be seen from fig. 9(e) (f) that the two have substantially the same trend, which shows that the pipeline module can more accurately describe the dynamic heat transfer characteristics of the pipeline after the control strategy is implemented.
Verification of measurement results of overall thermal characteristics of the air conditioning system:
the accuracy of the three modules, namely the water chilling unit module 102, the pipeline module 103 and the coil module 104, is verified respectively before, and the accuracy of the combined operation of the three modules is more important for evaluating the dynamic change of the indoor cooling capacity supplied by the air conditioning system after the demand response control strategy is implemented.
When the three modules are operated jointly, the whole system forms a closed loop (as shown in fig. 6), and the output parameter of the previous module is the input parameter of the next module. Taking the pipe module 103 as an example, the inlet water temperature of the pipe module 103 is actually the outlet temperature of the water chiller module 102 (chilled water supply temperature), and the outlet water temperature of the pipe module 103 is the inlet temperature of the coil module 104. The stable operation parameters before the implementation of the demand response strategy are used as initial parameters of the module, and the flow of chilled water and the air volume of the fan are not regulated when the whole control strategy is implemented, so that the chilled water flow and the air flow are considered to be the same as the initial values
Figure BDA0003285405710000211
The discrete form used for numerical solution is seen in table 1.
The purpose of the thermal characteristic measurement system is to accurately describe the dynamic change process of the air conditioning system for delivering the cooling capacity to the indoor space after the demand response strategy is implemented. In two sets of experiments, the air volume of the fan coil is kept unchanged all the time, so that the air supply temperature can directly reflect the change of cold quantity conveyed from the tail end of the air conditioning system to the indoor. The comparison between the measured air supply temperature and the experimental results of the overall thermal characteristics under the two control strategies is shown in fig. 10, and the overall thermal characteristic system more accurately predicts the variation trend of the air supply temperature under the two control strategies.
Compared with the verification result of a single module, the error of the combined system is slightly larger. The input parameters of each step length of the module are the acquired values of each step length in the experiment in the verification of a single module, so that the calculation error of the last step length of the module does not influence the next step length; in the combined system, the outlet parameter of the previous module is used as the inlet parameter of the next module, and the calculation result of the previous step is the initial state parameter of the next step, i.e. the calculation error of the previous module acts on the next module, and the error of the previous time step also affects the next step, thus causing the module deviation to be slightly larger. Even so, the root mean square error of the whole system is still small, 0.53 ℃ (shutdown) and 0.36 ℃ (tempering), respectively.
The verification result of the thermal characteristic measurement system of the air conditioner body can be obtained, and the whole thermal characteristic measurement system can accurately predict the dynamic change of the cooling capacity supplied to the indoor by the air conditioner system after the demand response control strategy is implemented.
The root mean square error summary results of the water chiller module 102 predicting the outlet water temperature, the coil module 104 predicting the supply air temperature, the pipeline module 103 predicting the pipeline outlet water temperature, and the overall thermal characteristic measurement system predicting the supply air temperature are shown in table 6. No matter the strategy of closing the refrigerator or improving the set value of the chilled water temperature, the prediction deviation of the three modules and the overall thermal characteristic measurement system is basically less than 0.5 ℃.
TABLE 6 root mean square error between individual modules and experimental results
Figure BDA0003285405710000212
Actual building verification (refrigerant cold amount commonality verification) of the chiller module 102:
in laboratory verification, the accuracy of the chiller module 102 in describing the dynamic changes in chilled water temperature was verified. However, on one hand, the water chilling unit for experiments can only complete the adjustment of the return water temperature of the chilled water due to the limitation of experimental conditions, the actual air conditioning system usually realizes the reset of the chilled water temperature by adjusting the supply water temperature of the chilled water, and on the other hand, the cold quantity Q of the refrigerant in the dynamic process obtained through experimentsrefThe versatility of (t) still needs to be further verified in the chiller of the actual building.
The control panel of the water chilling unit for secondary verification can realize resetting of the outlet water temperature of the chilled water and monitoring of the return water temperature of the chilled water supply, and the energy system monitoring platform of the building can monitor other operation parameters of the unit in real time. Basic information of the water chilling unit required in the verification is obtained through means of field investigation, equipment sample information collection, sample data fitting and short-term operation data acquisition, and is shown in a table 7.
TABLE 7 detailed parameters of a water chiller for an office building
Parameter(s) Numerical value
Refrigerant HCFC－123
Rated flow of chilled water 603m3/h
Evaporator mass 800kg
Refrigerant side heat transfer area 765m2
Heat transfer area of side of chilled water 545m2
Quality of chilled water in evaporator 350kg
Refrigerant mass in evaporator 240kg
C1 3132
C2 4028
n1 1.8
n2 －1.8
Two control strategy experiments are carried out on the unit in the test, wherein the strategy 1: closing the cold machine and simultaneously keeping the water pump and the tail end to operate; strategy 2: the temperature of the outlet water of the frozen water was changed from 10 ℃ to 12 ℃ as shown in Table 8.
TABLE 8 details of control strategies in actual building testing
Figure BDA0003285405710000221
The comparison between the measurement results and the experimental results of the four cold water chilling unit modules 102 in the test is shown in fig. 11, and the variation trends of the outlet water temperature of the modules and the tested chilled water under the four working conditions are basically consistent. The root mean square error between the module and the test result is shown in table 9, and the root mean square error between the module and the test result is smaller regardless of the shutdown strategy or the temperature reset strategy. This shows that, on the one hand, the water chiller module proposed by the subject has certain accuracy and universality; on the other hand, the law of the refrigerating capacity of the refrigerant obtained through laboratory tests and implemented by different strategies also has certain universality.
TABLE 9 details of control strategies in actual building testing
Verification policy Root mean square error
Shut-off refrigerator-1 (a) 0.18℃
Closing refrigerator-2 (b) 0.11℃
Resetting the outlet water temperature of the chilled water-1 (c) 0.15℃
Resetting the outlet water temperature of the chilled water-2 (d) 0.20℃
Correspondingly, the embodiment of the invention also provides a terminal, which comprises a processor, a memory and a computer program stored in the memory; wherein the computer program is executable by the processor to implement the thermal characteristic measurement method of the air conditioning system.
The terminal can be a desktop computer, a notebook, a palm computer, a cloud server and other computing equipment. The terminal may include, but is not limited to, a processor, a memory.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like, which is the control center of the terminal and connects the various parts of the overall terminal using various interfaces and lines.
The memory may be used to store the computer program, and the processor may implement various functions of the terminal by executing or executing the computer program stored in the memory and calling data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone, and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
Correspondingly, the embodiment of the invention also provides a computer readable storage medium, wherein the computer readable storage medium comprises a stored computer program; wherein the apparatus in which the computer readable storage medium is located is controlled to perform the thermal characteristic measurement method of the air conditioning system when the computer program is executed.
Wherein the thermal characteristic measurement system/terminal integrated module of the air conditioning system may be stored in a computer readable storage medium if it is implemented in the form of a software functional unit and sold or used as a separate product. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
the embodiment of the invention provides a thermal characteristic measuring method, a system, a terminal and a storage medium of an air conditioning system, wherein the air conditioning system comprises the following components: water chilling units, coils and pipes; the thermal property measurement method includes: acquiring various thermal characteristic initial parameters of the air conditioning system in real time, and acquiring the outlet water temperature of the water chilling unit according to the thermal characteristic initial parameters of the air conditioning system; acquiring the temperature of outlet water of a pipeline according to the temperature of a water outlet of a water chilling unit; acquiring the air supply temperature of the coil according to the temperature of the outlet water of the pipeline; obtaining a thermal characteristic measurement result of the air conditioning system according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of the cold quantity transmitted to the indoor by the air conditioning system after the implementation of the cold machine side control strategy. According to the invention, the measurement results of the water chilling unit, the coil pipe and the pipeline are combined, and compared with the prior art, the method has higher scene applicability and universality, and the measurement method is more effective and faster.
The above-mentioned embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, and it should be understood that the above-mentioned embodiments are only examples of the present invention and are not intended to limit the scope of the present invention. It should be understood that any modifications, equivalents, improvements and the like, which come within the spirit and principle of the invention, may occur to those skilled in the art and are intended to be included within the scope of the invention.

Claims (10)

1. A thermal characteristic measurement method of an air conditioning system is applied to the air conditioning system after a refrigerator-side control strategy is implemented, and the air conditioning system comprises the following steps: water chilling units, coils and pipes;
the thermal property measurement method includes:
acquiring initial parameters of thermal characteristics of the air conditioning system in real time; wherein the thermal characteristic initial parameters include: an average temperature of evaporator material within the chiller, an average temperature of refrigerant within the chiller, an average temperature of chilled water within the chiller, an average temperature of piping material, an average temperature of chilled water within the piping, an average temperature of insulation outside the piping, an average temperature of outside air, an outlet water temperature of the coil, and an inlet water temperature of the coil;
acquiring the outlet water temperature of the water chilling unit according to the average temperature of evaporator materials in the water chilling unit, the average temperature of a refrigerant in the water chilling unit and the average temperature of chilled water in the water chilling unit by combining a preset heat exchange coefficient between the refrigerant and the wall surface of the evaporator and a preset heat exchange coefficient between the wall surface of the evaporator and the chilled water;
acquiring the temperature of outlet water of a pipeline according to the temperature of the outlet water of the water chilling unit by combining the average temperature of a pipeline material, the average temperature of chilled water in the pipeline, the average temperature of a heat insulation material outside the pipeline and the average temperature of outside air;
acquiring the air supply temperature of the coil according to the outlet water temperature of the pipeline and by combining a preset saturated enthalpy value of air at the average temperature of the coil, the outlet water temperature of the coil, the inlet water temperature of the coil, the row number of the coil and a preset heat exchange area of water;
obtaining a thermal characteristic measurement result of the air conditioning system according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of delivering cold energy to the indoor by the air conditioning system after the cold machine side control strategy is implemented.
2. The method of claim 1, wherein obtaining the temperature of the air supplied to the coil comprises obtaining the temperature of the air supplied to the coil in a dry condition and obtaining the temperature of the air supplied to the coil in a wet condition; the coil pipes are composed of a plurality of rows, and the coil pipes in different rows can be in different dry and wet working conditions.
3. The method for measuring the thermal characteristics of the air conditioning system according to claim 1, wherein the obtaining of the initial parameters of the thermal characteristics of the air conditioning system in real time specifically comprises: the method comprises the steps of acquiring the average temperature of evaporator materials in a water chilling unit, the average temperature of a refrigerant in the water chilling unit, the average temperature of chilled water in the water chilling unit, the average temperature of pipeline materials, the average temperature of chilled water in a pipeline, the average temperature of heat insulation materials outside the pipeline, the average temperature of outside air, the outlet water temperature of a coil and the inlet water temperature of the coil in real time through a plurality of sensors.
4. The method of any one of claims 1 to 3, wherein the chiller side control strategy comprises an intermittent shutdown strategy, a partial chiller shutdown strategy and a chilled water temperature increase strategy; after the thermal characteristic measurement method is applied to the implementation of the control strategy at the cold machine side, a new stable state is formed.
5. A thermal characteristic measurement system of an air conditioning system is characterized by comprising an acquisition module, a water chiller module, a pipeline module, a coil pipe module and a thermal characteristic measurement module; wherein the content of the first and second substances,
the acquisition module is used for acquiring the initial parameters of the thermal characteristics of the air conditioning system in real time; wherein the thermal characteristic initial parameters include: an average temperature of evaporator material within the chiller, an average temperature of refrigerant within the chiller, an average temperature of chilled water within the chiller, an average temperature of piping material, an average temperature of chilled water within the piping, an average temperature of insulation outside the piping, an average temperature of outside air, an outlet water temperature of the coil, and an inlet water temperature of the coil;
the water chilling unit module is used for acquiring the outlet water temperature of the water chilling unit according to the average temperature of evaporator materials in the water chilling unit, the average temperature of a refrigerant in the water chilling unit and the average temperature of chilled water in the water chilling unit by combining a preset heat exchange coefficient between the refrigerant and the wall surface of the evaporator and a preset heat exchange coefficient between the wall surface of the evaporator and the chilled water;
the pipeline module is used for acquiring the temperature of outlet water of the pipeline according to the temperature of the outlet water of the water chilling unit by combining the average temperature of a pipeline material, the average temperature of chilled water in the pipeline, the average temperature of a heat insulation material outside the pipeline and the average temperature of outside air;
the coil pipe module is used for acquiring the air supply temperature of the coil pipe according to the outlet water temperature of the pipeline and by combining a preset saturated enthalpy value of air at the average temperature of the coil pipe, the outlet water temperature of the coil pipe, the inlet water temperature of the coil pipe, the row number of the coil pipe and a preset heat exchange area of water;
the thermal characteristic measurement module is used for obtaining a thermal characteristic measurement result of the air conditioning system according to the outlet water temperature of the water chilling unit, the outlet water temperature of the pipeline and the air supply temperature of the coil pipe; and the thermal characteristic measurement result is a dynamic change process of delivering cold energy to the indoor by the air conditioning system after the cold machine side control strategy is implemented.
6. The system of claim 5, wherein the obtaining the temperature of the air supplied to the coil comprises obtaining the temperature of the air supplied to the coil in a dry condition and obtaining the temperature of the air supplied to the coil in a wet condition; the coil pipes are composed of a plurality of rows, and the coil pipes in different rows can be in different dry and wet working conditions.
7. The system according to claim 5, wherein the acquiring module is configured to acquire the initial parameter of the thermal characteristic of the air conditioning system in real time, specifically: the method comprises the steps of acquiring the average temperature of evaporator materials in a water chilling unit, the average temperature of a refrigerant in the water chilling unit, the average temperature of chilled water in the water chilling unit, the average temperature of pipeline materials, the average temperature of chilled water in a pipeline, the average temperature of heat insulation materials outside the pipeline, the average temperature of outside air, the outlet water temperature of a coil and the inlet water temperature of the coil in real time through a plurality of sensors.
8. The system of any one of claims 5 to 7, wherein the chiller side control strategy comprises an intermittent shutdown strategy, a partial chiller shutdown strategy, and a chilled water temperature increase strategy; and after the thermal characteristic measurement system is applied to the implementation of the cold machine side control strategy, a new stable state is formed.
9. A terminal comprising a processor, a memory, and a computer program stored in the memory; wherein the computer program is executable by the processor to implement the thermal property measurement method of the air conditioning system according to any one of claims 1 to 4.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium comprises a stored computer program; wherein the apparatus where the computer readable storage medium is located is controlled to perform the thermal characteristic measurement method of the air conditioning system according to any one of claims 1 to 4 when the computer program is executed.
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