CN105737419B - Active dynamic cooling control device and method - Google Patents
Active dynamic cooling control device and method Download PDFInfo
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- CN105737419B CN105737419B CN201610112983.7A CN201610112983A CN105737419B CN 105737419 B CN105737419 B CN 105737419B CN 201610112983 A CN201610112983 A CN 201610112983A CN 105737419 B CN105737419 B CN 105737419B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
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Abstract
The invention provides an active dynamic cooling control device and method, wherein the device comprises a refrigeration basic unit, a control unit and a cooling space; wherein: a closed loop formed by sequentially connecting the compressor, the condenser and the evaporator is a refrigeration basic unit; the cooled object and the evaporator are both arranged in the cooling space; the control unit comprises a controller and a control valve; wherein: the control valve is arranged between the condenser and the evaporator, and the output cold quantity of the compressor is adjusted by changing the opening degree of the control valve; and the controller sends an adjusting instruction to the control valve according to the stored performance parameters and the real-time acquired operation parameters, so that the dynamic balance between the output cold quantity of the compressor and the heat exchange quantity of the cooled object in the refrigeration process is realized. The invention realizes active refrigeration by keeping the output cold quantity of the compressor to be the same as the heat exchange quantity of the cooled object in real time.
Description
Technical Field
The invention relates to the field of temperature preservation, in particular to an active dynamic cooling control device and method.
Background
Air conditioners and refrigeration devices are widely applied to the fields of quick-freezing preservation technology, beverage quick-cooling technology and the like which need to cool a cooled object. Rapid cooling is the main objective of air conditioners and refrigerators, and therefore the cooling rate of the cooled object becomes a key technical index. The existing air conditioner or refrigeration device generally adjusts the flow of the refrigerant of the refrigeration system through throttling elements such as a capillary tube, a thermostatic expansion valve and the like, and matches the heat load change of the cooled object corresponding to the refrigerant in a passive mode of adjusting the flow and the evaporation temperature of the refrigerant by taking the refrigeration cycle parameters such as the superheat degree of the outlet of an evaporator (an inner balance thermostatic expansion valve) or the over-cooling degree of the inlet of the capillary tube refrigerant as input parameters to realize the cooling of the cooled object. It can be seen that the heat transfer (cooling) process for cooling the cooled object is as follows: the refrigerant absorbs heat through evaporation to reduce the temperature of the wall surface of the evaporator → the evaporator transfers the cold energy to the air through the heat convection → the air transfers the cold energy to the cooled object through the heat convection.
After the refrigeration system is determined, the convective heat transfer coefficient of the refrigeration system is basically fixed. If the heat transfer capacity is limited by the convective heat transfer coefficient (i.e., air side limitation), the heat transfer capacity is increased by increasing the heat transfer temperature difference. In this way, in order to achieve the highest cooling rate during the cooling process, the maximum heat exchange temperature difference between the refrigerant and the object to be cooled needs to be maintained (even if the evaporation temperature of the refrigeration cycle is always kept to be the lowest). And the refrigeration cycle with the thermostatic expansion valve as a throttling element reduces the temperature of the goods in the process of cooling and adjusting the goods, the evaporation temperature of the refrigerant can be gradually reduced along with the reduction of the temperature of the cooled object, and the evaporation temperature is reduced from high to low, so that the heat exchange temperature difference between the refrigerant and the goods is reduced, and the cooling speed of the goods is influenced.
In an air conditioner or a refrigerating device using a capillary tube as a throttling element, particularly in the occasion of large cooling amplitude of a cooled object, the capacity of the capillary tube for adjusting the flow rate and the evaporation temperature of a refrigerating cycle refrigerant is limited; and the heat exchange amount in the temperature reduction process is limited by the refrigerating capacity of the unit and not limited by the heat transfer temperature difference, at the moment, if the reduction of the evaporation temperature along with the reduction of the temperature of the cooled object cannot be realized due to the limited adjusting range of the throttling device, the output cold quantity of the unit cannot be maximized, and the temperature reduction speed of the cooled object is reduced.
Disclosure of Invention
In view of this, the present invention provides an active dynamic cooling control device and method, which aims to achieve the fastest and reliable cooling of the cooled object.
The technical scheme adopted by the invention is as follows:
an active dynamic cooling control device comprises a refrigeration basic unit, a control unit and a cooling space; wherein:
a closed loop formed by sequentially connecting the compressor, the condenser and the evaporator is a refrigeration basic unit;
the cooled object and the evaporator are both arranged in the cooling space;
the control unit comprises a controller and a control valve; wherein:
the control valve is arranged between the condenser and the evaporator, and the output cold quantity of the compressor is adjusted by changing the opening degree of the control valve;
and the controller sends an adjusting instruction to the control valve according to the stored performance parameters and the real-time acquired operation parameters, so that the dynamic balance between the output cold quantity of the compressor and the heat exchange quantity of the cooled object in the refrigeration process is realized.
In the active dynamic temperature reduction control device, the input end of the controller is respectively connected with the compressor, the temperature sensor group and the evaporator fan and is used for collecting operation parameters; the output end is connected with the control valve and used for adjusting the valve opening of the control valve according to the collected operation parameters and the pre-stored performance parameters.
In the active dynamic temperature reduction control device, the temperature sensor group comprises a first temperature sensor and a second sensor which are respectively used for collecting the air supply temperature and the air return temperature of the evaporator.
In the active dynamic temperature reduction control device, the prestored performance parameters comprise the performance parameters of a compressor and the performance parameters of an evaporator fan; wherein:
the performance parameters of the compressor are a performance curve of the compressor and a relation curve between the refrigerating capacity of the compressor and the operation parameters, and the operation parameters comprise evaporation temperature, condensation temperature, suction and exhaust pressure, input power and suction pressure relation curves;
the performance parameter of the evaporator fan is the relationship between the fan rotating speed and the mass flow.
An active dynamic cooling control method specifically comprises the following steps:
a heat transfer step: the refrigerant in the evaporator evaporates to absorb heat so as to reduce the temperature of the wall surface of the evaporator, and the cold energy obtained by temperature reduction is transferred to the air in the temperature reduction space through convection heat transfer and then further transferred to the cooled object;
an adjusting step: during the heat transfer step, the controller combines the real-time collected operation parameters according to the stored performance parameters of the compressor and the evaporator, and adjusts the opening of the control valve to realize the dynamic balance between the output cold quantity of the compressor and the heat exchange quantity of the cooled object in the refrigeration process until the temperature of the cooled object reaches a set level.
In the active dynamic temperature-lowering control method, the output cold energy of the compressor is the heat exchange amount Q from the refrigerant in the evaporator to the object to be cooled a1 ＝kA(T o -T e )；
In the above formula:
a is the heat exchange area of the cooled object;
T o is the temperature of the cooled object;
T e is the refrigerant evaporating temperature;
k is the heat exchange coefficient between the refrigerant and the cooled object;
in the above formula:
h 1 the heat convection coefficient between the refrigerant and the wall surface;
delta is the evaporator wall thickness;
lambda is the heat conduction coefficient of the wall surface of the evaporator;
h 2 the heat exchange coefficient between the wall surface of the evaporator and the air is taken as the heat exchange coefficient;
h 3 the heat exchange coefficient of the air and the cooled object;
the heat exchange amount of the object to be cooled, i.e., the heat exchange amount Q of the object to be cooled from the cold air of the evaporator a2 ＝cm(T in -T out )；
In the above formula:
c is the air specific heat;
m is the air mass flow;
T in the return air temperature of the evaporator;
T out the temperature of the air supplied to the evaporator.
The controller analyzes and obtains the conclusion that the heat exchange limits the cold quantity transmission or the compressor refrigerating quantity limits the cold quantity transmission by monitoring the relation between the cold quantity output by the compressor and the heat exchange quantity of the cooled object in real time, and further enables the cold quantity output by the compressor and the heat exchange quantity of the cooled object to be dynamically equal through the controller until the cooled object reaches the set temperature.
In the active dynamic cooling control method, when the heat transfer quantity between the refrigerant and the cooled object is limited by the output refrigerating capacity of the compressor, the control valve keeps the maximum opening degree, so that the compressor outputs the maximum refrigerating capacity, and the cooling speed of the cooled object is fastest.
In the active dynamic cooling control method, when the heat transfer capacity of the refrigerant and the cooled object is limited by the convective heat transfer coefficient, the control valve keeps the minimum opening, so that the evaporation temperature and the cooled object keep the maximum heat transfer temperature difference, and the cooling speed of the cooled object is fastest.
The invention has the following beneficial effects:
the active dynamic cooling control method of the invention takes the operation parameters of a refrigeration compressor of a refrigerating unit, the operation parameters of a fan of an evaporator and the return air temperature of the evaporator as main references, takes the adjustment of a control valve as a main means, matches the refrigerating capacity output by the compressor with the heat exchange capacity of a cooled object, enables the maximum heat exchange capacity to be achieved between the cooled object and a refrigerant, and rapidly cools the cooled object.
Drawings
The present invention will be better understood and appreciated more fully when considered in conjunction with the accompanying drawings. The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure.
FIG. 1 is a schematic structural diagram of an active dynamic cooling control device according to the present invention;
FIG. 2 is a first graph showing the relationship between the refrigerating capacity of the compressor and the heat exchange capacity of the cooled object in an active dynamic cooling control device according to the present invention;
FIG. 3 is a second graph (limited by the heat transfer coefficient) of the relationship between the refrigerating capacity of the compressor and the heat transfer capacity of the cooled object of the active dynamic cooling control device according to the present invention;
fig. 4 is a third diagram (under the condition of limited refrigerating capacity of the compressor) of the active dynamic temperature-reducing control device of the invention, showing the relationship between the refrigerating capacity of the compressor and the heat exchange capacity of the cooled object.
In the figure:
1. the air conditioner comprises a compressor 2, a condenser 3, a control valve 4, an evaporator 5, a controller 6, an evaporator fan 7, a cooling space 8, a blowing air temperature sensor 9, a return air temperature sensor 10 and a cooled object.
Detailed Description
The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and examples.
As shown in fig. 1, an active dynamic cooling control device mainly includes a compressor 1, a condenser 2, a control valve 3, an evaporator 4 and a controller 5; wherein:
the compressor 1, the condenser 2 and the evaporator 4 are connected in sequence to form a closed loop as a refrigeration basic unit;
the evaporator 4 and the cooled object 10 are arranged in the cooling space 7;
the input end of the controller 5 is respectively connected with the compressor 1, an air supply temperature sensor 8 for acquiring temperature parameters of the evaporator 4, an air return temperature sensor 9 and an evaporator fan 6, the output end of the controller is connected with a control valve 3 arranged between the condenser 2 and the evaporator 4, and the output cold quantity of the compressor and the heat exchange quantity of a cooled object in the refrigeration process are dynamically the same by adjusting the opening degree of the controller.
The device realizes the cooling process of the cooled object 10 specifically as follows:
the controller 5 cools and transfers cold to the object 10 to be cooled according to the collected operating parameters of the compressor 1 and the evaporator fan 6 and the stored data including the performance parameters of the compressor 1 and the evaporator fan 6. The compressor performance parameter is a compressor performance curve, namely the relationship between the refrigerating capacity of the compressor and each related operation parameter; such as: the relationship curve of the refrigerating capacity of the compressor, the evaporating temperature/condensing temperature, the suction and exhaust pressure, the input power and the like; the fan performance parameter refers to the relationship between the fan rotation speed and the mass flow. Specifically, the method comprises the following steps:
the refrigerant in the evaporator 4 evaporates and absorbs heat to reduce the wall temperature of the evaporator 4, and by performing convection heat transfer, the cold energy obtained by the temperature reduction is transferred to the air in the temperature-reducing space 7, and the air further transfers the obtained cold energy to the object to be cooled 10 (for example, fresh air) by the convection heat transfer.
The specific heat transfer process equation is as follows:
heat exchange amount Q between refrigerant and object to be cooled a1 ＝kA(T o -T e )
In the above formula:
a is a heat exchange area (object to be cooled 10);
T o is the temperature of the cooled object;
T e is the refrigerant evaporation temperature;
k is the heat exchange coefficient between the refrigerant and the cooled object;
in the above formula:
h 1 the heat convection coefficient between the refrigerant and the wall surface;
delta is the evaporator wall thickness;
lambda is the heat conduction coefficient of the wall surface of the evaporator;
h 2 the heat exchange coefficient between the wall surface of the evaporator and the air is taken as the heat exchange coefficient;
h 3 which is the heat transfer coefficient of air to the object being cooled.
After the refrigeration system determines, A, (delta, lambda and h in the parameters 1 、h 2 、h 3 ) And k determined by the above can be regarded as a constant, that is, the heat exchange amount Q of the refrigerant with the object 10 to be cooled a With temperature as the main variable, i.e. Q a ＝f(T e ,T o ). As shown in fig. 2, assume a cooling target temperature T 1 ＝T o ＞T 2 ＞T 3 ＞T 4 ＞T 5 It can be seen that, when the temperature of the object to be cooled is given, Q a With refrigerant evaporation temperature T e Is increased and decreased, and is linear. At the different temperatures of the objects to be cooled,Q a and T e The relationship (c) is a straight line with a negative slope.
At the same time, since the heat exchange amount of the object to be cooled 10 is sent out via the cold air of the evaporator 4, therefore:
Q a2 ＝cm(T in -T out )
in the above formula:
c is the specific heat of air;
m is the air mass flow;
T in the return air temperature of the evaporator;
T out the temperature of the air supplied to the evaporator.
Refrigerating capacity Q of compressor c With refrigerant evaporation temperature T e And refrigerant condensation temperature T c In connection with, when a refrigerant system is determined, T c Substantially unchanged, i.e. compressor capacity Q c At refrigerant evaporation temperature T e Is a major variable, i.e. Q c ＝f(T e ) Referring to fig. 2, it can be seen that the compressor cooling capacity Q is c With refrigerant evaporation temperature T e Is increased.
Q a1 ＝kA(T o -T e ) The classical formula of heat transfer is that the heat exchange quantity of the refrigerant and the cooled object is obtained from the perspective of heat exchange, and Q a2 ＝cm(T in -T out ) The cold quantity of the air obtained from the evaporator is obtained from the perspective of the air. If the system reaches steady state, the two values are equal. But since the cooling process of the cooled object is a dynamic process, the two are not equal. The invention analyzes whether the heat exchange limits the cold quantity transmission or the compressor refrigerating capacity limits the cold quantity transmission by utilizing the inequality of the two values, thereby realizing the control of the fastest cooling speed.
When the refrigeration system is started, the refrigerant evaporating temperature T e Higher, set to T e，1 And the refrigerating capacity of the compressor at the moment is set as Q c，1 The amount of heat exchange between the refrigerant and the object to be cooled is
。
The controller 5 detects the evaporator supply air temperature T through the supply air temperature sensor 8 and the return air temperature sensor 9 respectively in And evaporator return air temperature T out And calculating the heat exchange amount of the cooled object by combining the running data of the evaporator fan 6 sent back in real time
(ii) a The concrete formula is
Wherein m is the mass flow of air, the rotating speed parameter of the fan 6 of the evaporator is transmitted back to the controller 5 in real time, the controller 5 can obtain the mass flow of the air supplied by the fan according to the relation between the rotating speed and the mass flow of the fan stored in the controller 5, namely the mass flow can be obtained by comparing the operating parameter of the fan 6 of the evaporator with the performance parameter stored in the controller 5;
meanwhile, the real-time operation data of the compressor is also transmitted back to the controller 5, and the controller 5 compares the real-time operation data with the pre-stored performance data of the compressor to calculate the refrigerating capacity Q of the compressor c，1 (ii) a The compressor 1 returns the real-time operation parameters to the controller 5, and the refrigerating capacity of the compressor 1 can be obtained by comparing the real-time operation parameters with the corresponding compressor performance curve stored in the controller 5.
Due to Q at this time c，1 Is greater than
The controller 5 issues a command to decrease the opening of the control valve 3 to lower the refrigerant evaporation temperature to T e，2 The output cold quantity of the compressor is the same as the heat exchange quantity of the cooled object;
then the cooled object will continue to cool down, when the temperature is reduced to T 2 If the refrigeration unit is still according to T e，2 When the compressor is operated, the output cold quantity of the compressor is larger than the heat exchange quantity of the cooled object, and the opening degree of the valve needs to be reduced to reduce the evaporation temperature to T similar to the regulation process e，3 The output cold quantity of the compressor is the same as the heat exchange quantity of the cooled object.
Namely, the relationship between the heat exchange quantity of the cooled object and the output cold quantity of the compressor is monitored in real time, the output cold quantity of the compressor is equal to the heat exchange quantity of the cooled object through the control of the controller 5 until the cooled object 10 reaches the set temperature T 5 Corresponding refrigerant evaporating temperature T e,5 。
When a new object to be cooled 10 is added during the period, the average temperature of the object to be cooled 10 rises to T 4 At this time, the refrigerator 5 is still at the refrigerant evaporation temperature T by adjusting the valve opening of the control valve 3 e,5 The output cold quantity of the refrigerating system is smaller than the possible heat exchange quantity of the cooled object;
the controller 5 increases the opening of the control valve 3 by calculating and comparing the relationship between the heat exchange amount of the cooled object and the output cold amount of the compressor, so that the evaporation temperature is increased to T e,6 To make the compressor output cold quantity Q c，4 (point 9 in FIG. 2) is equal to the heat exchange amount of the object to be cooled
(point 9 in FIG. 2). And then continuously adjusting the temperature reduction process according to the temperature change of the cooled object.
In addition, the cooling control device can also realize two special treatment working conditions of fastest cooling speed and improved heat exchange quantity:
1. after the refrigeration system is determined, the heat transfer capacity is only increased by increasing the heat transfer temperature difference because the heat transfer coefficient is basically fixed and the heat transfer capacity is limited by the heat transfer coefficient (air side). Therefore, in the cooling process, the highest cooling speed is achieved, the evaporation temperature of the refrigeration cycle can be kept to be the lowest, namely, the maximum heat exchange temperature difference between the refrigerant and the cooled object is maintained. The specific implementation process is as follows:
when the refrigeration system is started, the evaporating temperature is set to T e，1 At this time, the refrigerating capacity of the compressor is Q c，1 At this evaporation temperature, the amount of heat exchange between the refrigerant and the object to be cooled is
. The controller 5 detects the evaporator supply air temperature T through the supply air temperature sensor 8 and the return air temperature sensor 9 in And evaporator return air temperature T out And calculating the heat exchange amount of the cooled object by the real-time returned operation data of the evaporator fan 6
. Real-time operation data of the compressor is also transmitted back to the controller, and the controller calculates the refrigerating capacity Q of the compressor by comparing the real-time operation data of the compressor with the stored performance data c，1 . Because of the refrigerating capacity Q of the compressor at this time c，1 Greater than the maximum heat exchange with the object to be cooled by
The controller 5 issues a control command for reducing the opening of the control valve 3. When the valve opening is adjusted to a minimum, the evaporation temperature T e,2 The output cold quantity of the lower compressor is larger than the possible heat exchange quantity of the cooled object, and the unit maintains the lowest evaporation temperature T e,2 . The temperature of the cooled object is reduced to the template temperature T 2 At this time, the compressor outputs the cooling capacity Q c，2 Still greater than the heat exchange amount of the cooled object. In the cooling process, the opening of the control valve is always kept at the minimum opening to keep the maximum temperature difference between the evaporation temperature and the cooled object, so that the cooled object 10 is quickly cooled.
The refrigerating capacity is adjusted based on the main basis of the operation parameters of the compressor, the air supply and return temperature of the evaporator and the operation parameters of the fan of the evaporator. The existing compressor performance data and evaporator fan performance data are fully utilized, and dynamic operation adjustment of the refrigeration working condition can be realized without a complex test means;
the cooling speed of the cooled object 10 is improved to the maximum extent by dynamically matching the refrigerating capacity output by the compressor 1 with the heat exchange capacity of the cooled object 10; under extreme working conditions, the heat exchange amount between the refrigerant and the cooled object 10 can be maximized by simply adjusting the unit, and the fastest cooled speed of the cooled object 10 is realized.
Namely: when the heat transfer quantity of the refrigerant and the cooled object is limited by the convective heat transfer coefficient, the control valve keeps the minimum opening degree, so that the evaporation temperature and the cooled object keep the maximum heat transfer temperature difference, and the cooling speed of the cooled object is the fastest.
2. After the refrigeration system is determined, the heat convection coefficient is basically fixed and large enough, and the heat transfer quantity is limited by the output power of the compressor. The heat exchange is increased by maximizing the compressor output. Therefore, in the cooling process, the fastest cooling speed is achieved, even if the evaporation temperature of the refrigeration cycle is kept to be the highest, and the minimum heat exchange temperature difference between the refrigerant and the cooled object is maintained. The specific implementation process is as follows:
when the refrigeration system is started, the evaporating temperature is set to T e,1 At this time, the refrigerating capacity of the compressor is Q c，1 At this evaporation temperature, the heat exchange amount between the refrigerant and the object to be cooled is
. The controller (5) detects the air supply temperature T of the evaporator through the air supply temperature sensor 8 and the return air temperature sensor 9 in And evaporator return air temperature T out And calculating the heat exchange amount of the cooled object by the running data of the evaporator fan 6 sent back in real time
. Real-time running data of the compressor is also transmitted back to the controller, and the controller compares the real-time running data with the input performance data of the compressor to calculate the refrigerating capacity Q of the compressor c，1 . At this time, the cooling capacity Q of the compressor c，1 Less than a maximum heat exchange with the object to be cooled of
. The controller 5 issues a control command for increasing the opening of the control valve 3. However, when the valve opening is adjusted to the maximum, the evaporation temperature is T e,2 The output cold quantity of the compressor is still less than the possible heat exchange quantity of the cooled object at the evaporation temperature, and the unit maintains the highest evaporation temperature T e,2 . The temperature of the cooled object is reduced to the target temperature T 2 At this timeOutput cold quantity Q of compressor c，2 Still less than the heat exchange amount of the cooled object. In the cooling process, the opening of the control valve is always kept at the maximum opening so as to keep the maximum cold output of the compressor.
Namely: when the heat transfer quantity between the refrigerant and the cooled object is limited by the output refrigerating capacity of the compressor, the control valve keeps the maximum opening degree, so that the compressor outputs the maximum refrigerating capacity, and the cooling speed of the cooled object is fastest.
The invention realizes the active cooling of the cooling system to the cooled object through the controller, and adjusts the refrigerating output through the control valve by taking the air supply and return temperature of the evaporator, the running parameters of the fan of the evaporator and the running parameters of the compressor as main references, thereby dynamically realizing the matching of the refrigerating output of the compressor and the heat exchange output of the cooled object.
Embodiments of the present invention are described in detail above with reference to the drawings, which are provided to provide a further understanding of the invention. It should be understood that the above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily made by those skilled in the art without substantially departing from the present invention are also included in the scope of the present invention.
Claims (7)
1. An active dynamic cooling control device is characterized by comprising a refrigeration basic unit, a control unit and a cooling space; wherein:
a closed loop formed by sequentially connecting the compressor, the condenser and the evaporator is a refrigeration basic unit;
the cooled object and the evaporator are both arranged in the cooling space;
the control unit comprises a controller and a control valve; wherein:
the control valve is arranged between the condenser and the evaporator, and the output cold quantity of the compressor is adjusted by changing the opening degree of the control valve;
the controller sends an adjusting instruction to the control valve according to the stored performance parameters and the real-time acquired operation parameters, so that the dynamic balance between the output cold quantity of the compressor and the heat exchange quantity of the cooled object in the refrigeration process is realized;
the output cold energy of the compressor is the heat exchange quantity Q from the refrigerant of the evaporator to the cooled object a1 ＝kA(T o -T e ) (ii) a In the above formula:
a is the heat exchange area of the cooled object;
T o is the temperature of the cooled object;
T e is the refrigerant evaporation temperature;
k is the heat exchange coefficient between the refrigerant and the cooled object;
in the above formula:
h 1 the heat convection coefficient between the refrigerant and the wall surface;
delta is the evaporator wall thickness;
lambda is the heat conduction coefficient of the wall surface of the evaporator;
h 2 the heat exchange coefficient between the wall surface of the evaporator and the air is taken as the heat exchange coefficient;
h 3 the heat exchange coefficient of the air and the cooled object;
the heat exchange amount of the object to be cooled, i.e., the heat exchange amount Q of the object to be cooled fed from the cold air of the evaporator a2 ＝cm(T in -T out ) (ii) a In the above formula:
c is the specific heat of air;
m is the air mass flow;
T in the return air temperature of the evaporator;
T out supplying air to the evaporator;
the controller analyzes and obtains the conclusion that the heat exchange limits the cold quantity transmission or the compressor refrigerating quantity limits the cold quantity transmission by monitoring the relation between the cold quantity output by the compressor and the heat exchange quantity of the cooled object in real time, and further enables the cold quantity output by the compressor and the heat exchange quantity of the cooled object to be dynamically equal through the controller until the cooled object reaches the set temperature.
2. The active dynamic cooling control device according to claim 1, wherein an input end of the controller is connected to the compressor, the temperature sensor group, and the evaporator fan, respectively, for acquiring operation parameters; the output end is connected with the control valve and used for adjusting the valve opening of the control valve according to the collected operation parameters and the pre-stored performance parameters.
3. The active dynamic cooling control device of claim 2, wherein the set of temperature sensors comprises a first temperature sensor and a second temperature sensor for respectively acquiring a supply air temperature and a return air temperature of the evaporator.
4. The active dynamic cooling control device of claim 2, wherein the pre-stored performance parameters include compressor performance parameters and evaporator fan performance parameters; wherein:
the performance parameters of the compressor are a performance curve of the compressor and a relation curve between the refrigerating capacity of the compressor and the operation parameters, and the operation parameters comprise evaporation temperature, condensation temperature, suction and exhaust pressure, input power and suction pressure relation curves;
the performance parameter of the evaporator fan is the relationship between the rotating speed of the fan and the mass flow.
5. An active dynamic cooling control method for an active dynamic cooling control device according to any one of claims 1 to 4, comprising the following steps:
a heat transfer step: the refrigerant in the evaporator evaporates and absorbs heat to reduce the temperature of the wall surface of the evaporator, and the cold energy obtained by temperature reduction is transferred to the air in the cooling space through convection heat exchange and then further transferred to the cooled object;
and (3) adjusting: during the heat transfer step, the controller combines the real-time collected operation parameters according to the stored performance parameters of the compressor and the evaporator, and adjusts the opening of the control valve to realize the dynamic balance of the output cold quantity of the compressor and the heat exchange quantity of the cooled object in the refrigeration process until the temperature of the cooled object reaches the set level.
6. The active dynamic cooling control method according to claim 5, wherein when the heat transfer amount between the refrigerant and the cooled object is limited by the output cooling capacity of the compressor, the control valve maintains the maximum opening degree, so that the compressor outputs the maximum cooling capacity, and the cooling speed of the cooled object is fastest.
7. The active dynamic cooling control method according to claim 5, wherein in the active dynamic cooling control method, when the heat transfer amount between the refrigerant and the object to be cooled is limited by the convective heat transfer coefficient, the control valve maintains a minimum opening degree, so that the evaporation temperature and the object to be cooled maintain a maximum heat transfer temperature difference, and the cooling speed of the object to be cooled is fastest.
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| CN107255355B (en) * | 2017-05-05 | 2020-06-19 | 珠海格力电器股份有限公司 | Air conditioning system control device and method |
| CN108397853B (en) * | 2018-02-11 | 2019-11-01 | 珠海格力电器股份有限公司 | Air-conditioner set control method and device |
| CN114963683B (en) * | 2022-06-01 | 2023-09-15 | 深圳市汉盛制冷科技有限公司 | Accurate temperature control refrigerating system |
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