CN117628641A - Air-cooled unit of air conditioner and frost control method thereof - Google Patents
Air-cooled unit of air conditioner and frost control method thereof Download PDFInfo
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- CN117628641A CN117628641A CN202311676178.3A CN202311676178A CN117628641A CN 117628641 A CN117628641 A CN 117628641A CN 202311676178 A CN202311676178 A CN 202311676178A CN 117628641 A CN117628641 A CN 117628641A
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- 238000002360 preparation method Methods 0.000 claims abstract description 56
- 230000009467 reduction Effects 0.000 claims abstract description 19
- 230000008569 process Effects 0.000 claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 45
- 239000003507 refrigerant Substances 0.000 claims description 38
- 238000012544 monitoring process Methods 0.000 claims description 34
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- 238000001704 evaporation Methods 0.000 claims description 4
- BULVZWIRKLYCBC-UHFFFAOYSA-N phorate Chemical compound CCOP(=S)(OCC)SCSCC BULVZWIRKLYCBC-UHFFFAOYSA-N 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 4
- 230000002829 reductive effect Effects 0.000 description 13
- 238000004378 air conditioning Methods 0.000 description 9
- 230000001629 suppression Effects 0.000 description 9
- 230000003247 decreasing effect Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 230000005764 inhibitory process Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 230000008859 change Effects 0.000 description 3
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- 238000005057 refrigeration Methods 0.000 description 3
- 238000012937 correction Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
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Abstract
The invention discloses a frost control method of an air-cooled unit of an air conditioner, which comprises the following steps: after the machine set is started for a period of time, calculating the reduction amplitude of the heating energy efficiency ratio; when the reduction amplitude of the heating energy efficiency ratio is always larger than a preset value within a certain period of time, starting a defrosting mode and a defrosting preparation mode while the unit continues heating; in the process of performing the defrosting mode and the defrosting preparation mode, the descending amplitude of the heating energy efficiency ratio is calculated, and the operation mode of the unit is switched according to the descending amplitude of the heating energy efficiency ratio, or the operation mode of the unit is switched after corresponding judging conditions are selected. The invention combines the reduction amplitude of heating energy efficiency ratio with the defrosting mode, and simultaneously opens the defrosting preparation mode while opening the defrosting mode, thereby achieving the effects of accurately controlling the frost and saving energy.
Description
Technical Field
The invention relates to the technical field of air conditioner defrosting control, in particular to a defrosting control method of an air-cooled unit of an air conditioner.
Background
There are many defrosting methods of the existing air conditioning systems.
In order to solve the problem that continuous heating cannot be guaranteed when a unit is defrosted, the technical scheme is that a defrosting pipeline is additionally arranged in an air conditioning unit, the inlet end of the defrosting pipeline is positioned on a connecting pipeline of a four-way valve and an indoor unit, and the outlet end of the defrosting pipeline is positioned on a liquid inlet main pipe of the outdoor unit; the defrosting electromagnetic valve is arranged on the defrosting pipeline and is used for being opened when the defrosting operation of the air conditioner defrosting system is carried out, so that the unit can perform defrosting while heating normally.
In view of how the defrosting solenoid valve is triggered to open, defrosting conditions are preset in the prior art, and the defrosting solenoid valve is used for opening when operation parameters of an air conditioner defrosting system meet the defrosting conditions. The defrosting conditions to which it refers can include at least one of the following: the defrosting temperature is less than the preset temperature plus the ambient temperature correction value and is continued for a first preset duration; the system low pressure is less than the preset low pressure plus the ambient temperature correction value and is continued for a first preset duration; the difference value of the system low pressure of any one starting machine set and the system low pressure of other starting machine sets in the air conditioner defrosting system is in a preset difference value interval; the deviation of the low-pressure data in the system low-pressure and large-data platform is less than the preset low-pressure deviation, and the deviation of the defrosting temperature and the temperature data in the large-data platform is less than the preset temperature deviation. The decrease of the system low pressure in the second preset time period exceeds the first preset value, and the decrease of the defrosting temperature in the second preset time period exceeds the second preset value. The defrosting temperature is a temperature value monitored by a defrosting temperature sensing bulb, and the defrosting temperature sensing bulb is positioned on a heat exchanger branch of the outdoor unit. The system low pressure is the pressure value monitored by a low pressure sensor, and the low pressure sensor is positioned on the inlet pipe of the vapor-liquid separator. In the prior art, a defrosting pipeline is added in an original heat pump system, and a defrosting electromagnetic valve is additionally arranged in the defrosting pipeline and is used for controlling circulation of a refrigerant so as to realize defrosting of an outdoor unit.
Although the prior art achieves the technical effects of performing defrosting operation when defrosting is needed, and simultaneously realizing continuous heating of the unit, thereby shortening defrosting period, prolonging heating time of the unit and improving energy efficiency of the unit. However, the prior art has not completely defrosting effect due to defrosting while heating, and has long time after formally stopping defrosting. In addition, when the prior art is cited on a large-scale commercial air conditioning unit, the judgment of defrosting is difficult to be accurate.
Taking the defrosting control of a common air-cooled heat pump unit as an example, the defrosting control of the prior art judges whether to enter a defrosting mode by detecting the pressure and temperature parameters of an outdoor heat exchanger, the method needs more detection components and parts and is influenced by outdoor environment, outdoor dust and impurities are easy to adhere to the surfaces of fins to influence the heat exchange of the fins, and because the impurity layer exists, the low pressure is relatively low, the unit entering the defrosting mode by means of low-pressure detection is extremely easy to cause misjudgment, the defrosting mode failure is easy to occur or the defrosting condition judgment is wrong to perform frostless defrosting, and the two conditions greatly influence the heating performance and influence the user comfort experience.
Therefore, how to provide an energy-saving and efficient frost control method is a technical problem to be solved.
Disclosure of Invention
The invention provides an air-cooled system of an air conditioner and a defrosting control method thereof, aiming at solving the problems caused by singly adopting COP to enter a defrosting mode and the technical problem that entering the defrosting mode is not efficient enough in the prior art.
The invention provides a frost control method of an air-cooled unit of an air conditioner, which comprises the following steps:
after the machine set is started for a period of time, calculating the reduction amplitude of the heating energy efficiency ratio;
when the reduction amplitude of the heating energy efficiency ratio is always larger than a preset value within a certain period of time, starting a defrosting mode and a defrosting preparation mode while the unit continues heating; in the process of performing the defrosting mode and the defrosting preparation mode, the descending amplitude of the heating energy efficiency ratio is calculated, and the operation mode of the unit is switched according to the descending amplitude of the heating energy efficiency ratio, or the operation mode of the unit is switched after corresponding judging conditions are selected.
Further, in the process of performing the defrosting mode and the defrosting preparation mode, if the reduction amplitude of the heating energy efficiency ratio is always smaller than a preset value within a certain period of time, the defrosting mode and the defrosting preparation mode are closed, and the conventional heating mode is entered.
Further, in the process of performing the defrosting mode and the defrosting preparation mode, if the reduction amplitude of the heating energy efficiency ratio is larger than a preset value, the defrosting mode and the defrosting preparation mode are maintained, defrosting conditions are monitored in real time, and the operation duration of the defrosting mode is counted;
when the defrosting condition is met and/or the operation duration of the defrosting mode is greater than or equal to the preset duration, if defrosting preparation is finished at the moment, heating is suspended, and defrosting is started.
Further, when the defrosting condition and/or the operation duration of the defrosting mode are/is greater than or equal to the preset duration, if defrosting preparation is still in progress at the moment, waiting for defrosting preparation, suspending heating, and starting defrosting.
Further, the monitoring of the defrosting conditions includes:
monitoring whether the reduction amplitude of the heating energy efficiency ratio is larger than a preset value;
monitoring whether the continuous theta-second suction pressure meets the suction pressure less than or equal to a set value P;
monitoring whether the accumulated running time of the compressor meets the condition that the accumulated running time t is more than defrosting interval setting time t1;
monitoring whether the defrosting temperature detected by the defrosting temperature sensing bulb for 60 seconds continuously is less than or equal to the defrosting start setting temperature T 1 ；
Monitoring whether the system pressure difference meets the system pressure difference which is more than the four-way valve reversing target pressure difference delta P;
monitoring whether the water outlet temperature of the unit meets the water outlet temperature which is more than the minimum tolerable water outlet temperature T of defrosting 2 ；
It is monitored whether the compressor of the unit has been running for more than N minutes.
Further, the frost suppression mode includes the steps of: and directly introducing the refrigerant at the exhaust port of the compressor of the unit into the fin refrigerant pipe of the evaporator.
Further, the defrosting preparation mode includes the steps of:
loading the compressor to be full in a preset loading time period;
the main throttle element is opened to a target opening X;
adjusting the target temperature of the water outlet to the target water temperature T of defrosting preparation m 。
Further, the heating energy efficiency ratio is reduced by dividing the value of the COP after the last defrosting is finished and the current time COP is subtracted from the COP after the last defrosting is finished and the heating is finished for m minutes.
Further, the COP is calculated by adopting a formula cop=alpha pressure ratio, beta evaporation temperature, gamma water inlet temperature, delta water inlet temperature difference and eta.
The air-conditioning air-cooling unit comprises a controller, wherein the controller adopts the frost control method of the air-conditioning air-cooling unit in the technical scheme when the unit heats.
Further, the unit further includes:
a main circulation flow path including a compressor, an air side heat exchanger, a water side heat exchanger, a main throttling element, a four-way valve;
and one end of the bypass branch is connected with the refrigerant inlet of the water side heat exchanger, and the other end of the bypass branch is connected with the fin refrigerant pipe of the air side heat exchanger.
The invention judges whether the unit needs to enter the frost inhibition mode by detecting the COP change of the unit, and when the delta COP enters the preset value range for a period of time, the frost inhibition mode is started, and has the advantages of controlling the unit to frost and defrosting to a certain extent under the condition of no shutdown, and the mode can prolong the running time of the unit and immediately stop defrosting when a frost layer exists. Meanwhile, the invention opens the defrosting mode and simultaneously opens the defrosting preparation mode, so that defrosting can be performed more efficiently. The invention can judge whether the defrosting mode needs to be started and when the defrosting mode is started according to the operation time of the defrosting mode and the change condition of delta COP after the defrosting mode is started, so that the defrosting judgment is more accurate, and the problems of 'no defrosting, no defrosting and inaccurate defrosting time' of the traditional air-cooled heat pump unit are effectively solved.
Drawings
The invention is described in detail below with reference to examples and figures, wherein:
FIG. 1 is an overall flow chart of an embodiment of the present invention.
Fig. 2 is a refrigerant flow diagram of a cooling mode according to an embodiment of the present invention.
Fig. 3 is a refrigerant flow diagram of a heating mode according to an embodiment of the present invention.
Fig. 4 is a refrigerant flow diagram of a frost suppression mode according to an embodiment of the present invention.
Fig. 5 is a flow chart of a frost control according to an embodiment of the present invention.
Fig. 6 is a flow chart of a defrosting determination according to an embodiment of the present invention.
Fig. 7 is a flow chart of a defrosting determination according to another embodiment of the present invention.
Fig. 8 is a flow chart of a defrosting determination according to a third embodiment of the present invention.
Fig. 9 is an overall flow chart of an embodiment of the present invention.
Fig. 10 is a table of parameter descriptions for an embodiment of the present invention.
Description of the drawings:
1. a compressor;
2. a four-way valve;
3. a fin;
4. a blower;
5. a primary throttling element;
6. a water side heat exchanger;
7. and a bypass valve.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Thus, reference throughout this specification to one feature will be used in order to describe one embodiment of the invention, not to imply that each embodiment of the invention must be in the proper motion. Furthermore, it should be noted that the present specification describes a number of features. Although certain features may be combined together to illustrate a possible system design, such features may be used in other combinations not explicitly described. Thus, unless otherwise indicated, the illustrated combinations are not intended to be limiting.
As shown in fig. 1, an exemplary embodiment of an air-cooled unit for an air conditioner of the present invention includes a main circulation flow path and a bypass path.
The main circulation flow path comprises a compressor 1, an air side heat exchanger, a water side heat exchanger 6, a main throttling element 5 and a four-way valve 2. Wherein the air side heat exchanger comprises fins 3 and fans 4.
In one embodiment, the main throttling element 5 is an electronic expansion valve.
The bypass branch is provided with a bypass valve, one end of the bypass branch is connected with the refrigerant inlet of the water side heat exchanger, and the other end of the bypass branch is connected with the fin refrigerant pipe of the air side heat exchanger.
In one embodiment, the bypass valve employs a solenoid valve.
As shown in fig. 2, when the unit is operated in the normal cooling mode, the refrigerant enters the four-way valve 2 from the discharge side of the compressor 1, passes through the air side heat exchanger, then the main throttling element 5, then the water side heat exchanger 6, and finally returns to the suction side of the compressor.
The refrigerant in the normal refrigeration mode passes through the compressor 1, the four-way valve 2, the air side heat exchanger (the fin 3 and the fan 4), the main throttling element 5 and the water side heat exchanger 6 in sequence.
As shown in fig. 3, when the unit is operated in the conventional heating mode, the refrigerant enters the four-way valve 2 from the discharge side of the compressor 1, passes through the water side heat exchanger 6, then the main throttling element 5, then the air side heat exchanger, and finally returns to the suction side of the compressor.
The refrigerant in the conventional heating mode passes through the compressor 1, the four-way valve 2, the water side heat exchanger 6, the main throttling element 5 (electronic expansion valve) and the air side heat exchanger (the fins 3 and the fan 4) in sequence.
As shown in fig. 4, when the unit continues to heat and operates in the frost-suppressing mode, after the refrigerant enters the four-way valve 2 from the exhaust side of the compressor, the refrigerant passes through the water side heat exchanger 6, then the main throttling element 5, then the air side heat exchanger, and finally returns to the suction side of the compressor. The other route bypass branch passes through the bypass valve and then directly enters into the fin refrigerant pipe of the air side heat exchanger so as to inhibit frosting of the air side heat exchanger, if a thinner frost layer exists on the air side heat exchanger at the moment, the frost layer can be directly removed through the frost inhibiting mode, and the heating mode also continues to operate at the moment, so that the use of a user is not influenced.
The refrigerant in the frost suppression mode sequentially comprises two refrigerant flows, wherein one refrigerant flow is a compressor 1, a four-way valve 2, a water side heat exchanger 6, a main throttling element 5 and an air side heat exchanger (a fin 3 and a fan 4). The other is compressor 1- & gtfour-way valve 2- & gtbypass valve 7- & gtair side heat exchanger (fin 3 and fan 4).
The heating process of the invention is described in detail below, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 enters the water side heat exchanger 6 through the D port and the E port of the four-way valve 2 to exchange heat with water to prepare hot water, the high-temperature and high-pressure refrigerant gas is condensed into high-pressure medium-temperature refrigerant liquid, the high-pressure medium-temperature refrigerant liquid is throttled by the main throttling element 5 to become low-temperature and low-pressure refrigerant, the low-temperature and low-pressure refrigerant enters the fins 3, the heat exchange with air is enhanced under the action of the constant frequency fan 4, the low-temperature and low-pressure refrigerant gas is evaporated into low-temperature and low-pressure superheated gas, and the low-temperature and high-pressure refrigerant gas returns to the compressor 1 through the C port and the S port of the four-way valve to complete the heating refrigerant circulation. In the process, the temperature of the surface of the fin is reduced due to the refrigerant evaporation and heat exchange at the fin, water vapor in the air contacts the surface of the fin at low temperature, so that frost is formed, and the frost layer is gradually thickened along with the operation of heating circulation.
In order to realize the control of the frost of the air-cooled unit of the air conditioner in the process, the invention provides a frost control method of the air-cooled unit of the air conditioner.
As shown in fig. 5, in one embodiment, the frost control method of the air-cooled air-conditioning unit of the present invention includes the following steps.
After the machine set is started for a period of time, calculating the reduction amplitude of the heating energy efficiency ratio;
when the reduction amplitude of the heating energy efficiency ratio is always larger than a preset value within a certain period of time, starting a defrosting mode and a defrosting preparation mode while the unit continues heating;
and in the process of performing the defrosting mode and the defrosting preparation mode, calculating the descending amplitude of the heating energy efficiency ratio, and switching the operation mode of the air-cooled unit according to the descending amplitude of the heating energy efficiency ratio, or selecting corresponding judgment conditions and then switching the operation mode of the air-cooled unit.
As can be seen from the above description, the operation modes of the unit of the present invention include: the invention relates to a conventional refrigeration mode, a conventional heating mode, a defrosting preparation mode and a defrosting mode, and the conventional refrigeration mode is not discussed in detail in the invention because the invention discusses a defrosting control method, but the defrosting mode and the defrosting preparation mode are two modes which are simultaneously opened, because when the defrosting mode is opened, a unit is still continuously heated, the defrosting mode is not the defrosting mode, only the defrosting process is slowed down, or a condensed thinner frost layer is removed, and if the current defrosting speed of the unit is higher or other defrosting modes cannot effectively inhibit frost, the invention can rapidly enter the defrosting mode because the defrosting preparation mode is simultaneously opened, thereby effectively defrosting in time.
In a specific embodiment, in the process of performing the defrosting mode and the defrosting preparation mode, if the heating energy efficiency ratio is reduced by a degree smaller than a preset value within a certain period of time, the defrosting mode and the defrosting preparation mode are closed, and the conventional heating mode is entered.
If the current frosting speed of the unit is slower, or the condensed frost layer is thinner, and the like, after the frost suppression mode is adopted, the frosting degree of the air side heat exchanger of the unit is well controlled, and the heating energy ratio is reduced to be smaller than or equal to a preset value, so that the unit can be converted into a conventional heating mode, and the problems of 'frostless frosting, frosting failure and inaccurate frosting time' of the traditional large air-cooled unit are effectively solved.
The invention is characterized in that the decrease of the heating energy efficiency ratio is used for detecting whether to enter a defrosting mode, the prior art generally adopts COP to detect whether to enter the defrosting mode, if the single reduction of COP is used for judging defrosting, the single reduction of COP falls into a frostless defrosting and defrosting inaccurate error area, because the COP is reduced, the reasons are various, the refrigerant circulation is blocked, the refrigerant quantity is small, the capacity is insufficient, the function of an economizer is not exerted, the condenser is not supercooled, the condenser frosts and the like, the defrosting is only one of the reasons, and the control of the COP reduction entering the defrosting is inaccurate, so the invention provides a more accurate defrosting control method.
As shown in fig. 6, in a specific embodiment, if the heating energy efficiency ratio is reduced by a magnitude greater than a preset value during the progress of the defrosting mode and the defrosting preparation mode, the defrosting mode and the defrosting preparation mode are maintained, and the defrosting condition is monitored in real time and the operation duration of the defrosting mode is counted;
when the defrosting condition is met, if defrosting is ready at the moment, heating is stopped, and defrosting is started.
In this embodiment, the invention always monitors the decrease amplitude of the thermal energy efficiency ratio in the process of the defrosting mode, and if the decrease amplitude of the thermal energy efficiency ratio is always larger than the preset value, the defrosting mode can be entered according to defrosting conditions. Because the defrosting preparation is finished before, the defrosting mode can be quickly entered, and compared with the technical scheme that the compressor, the throttling component and the like are controlled to enter the defrosting process after judgment in the prior art, the defrosting method is more efficient.
As shown in fig. 7, in a specific embodiment, if the heating energy efficiency ratio is reduced by a magnitude greater than a preset value during the progress of the defrosting mode and the defrosting preparation mode, the defrosting mode and the defrosting preparation mode are maintained, and the defrosting condition is monitored in real time and the operation duration of the defrosting mode is counted;
when the operation duration of the defrosting mode is greater than or equal to the preset duration, if defrosting preparation is completed at the moment, heating is suspended, and defrosting is started.
In the embodiment, the invention always monitors and controls the heat energy efficiency ratio decreasing amplitude in the process of the defrosting mode, and if the heat energy efficiency ratio decreasing amplitude is always larger than a preset value, whether to enter the defrosting mode can be judged according to the operation duration of the defrosting mode. Because defrosting preparation is performed at the same time, a defrosting mode can be quickly entered, and compared with the technical scheme that the compressor, the throttling component and the like are controlled to enter the defrosting process after judgment in the prior art, the defrosting method is more efficient.
As shown in fig. 8, in a specific embodiment, if the heating energy efficiency ratio is reduced by a magnitude greater than a preset value during the progress of the defrosting mode and the defrosting preparation mode, the defrosting mode and the defrosting preparation mode are maintained, and the defrosting condition is monitored in real time and the operation duration of the defrosting mode is counted;
when the defrosting condition is met and the operation duration of the defrosting mode is greater than or equal to the preset duration, if defrosting preparation is finished at the moment, heating is suspended, and defrosting is started.
In the embodiment, the invention always monitors and controls the heat energy efficiency ratio decreasing amplitude in the process of the defrosting mode, and if the heat energy efficiency ratio decreasing amplitude is always larger than a preset value, the defrosting mode is started as soon as possible when the defrosting condition is met and the operation duration of the defrosting mode is larger than or equal to the preset duration. Because defrosting preparation is performed at the same time, a defrosting mode can be quickly entered, and compared with the technical scheme that the compressor, the throttling component and the like are controlled to enter the defrosting process after judgment in the prior art, the defrosting method is more efficient.
In a supplementary embodiment, when the defrosting condition and/or the operation duration of the defrosting mode is/are greater than or equal to the preset duration, if defrosting preparation is still in progress at this time, waiting for defrosting preparation, suspending heating, and starting defrosting. And after defrosting preparation, defrosting is performed, so that the defrosting effect can be ensured.
In the above embodiment, monitoring the defrosting condition includes the following.
Monitoring whether the reduction amplitude of the heating energy efficiency ratio is larger than a preset value;
monitoring whether the continuous theta-second suction pressure meets the suction pressure less than or equal to a set value P;
monitoring whether the accumulated running time of the compressor meets the condition that the accumulated running time t is more than defrosting interval setting time t1;
monitoring whether the defrosting temperature detected by the defrosting temperature sensing bulb for 60 seconds continuously is less than or equal to the defrosting start setting temperature T 1 ；
Monitoring whether the system pressure difference meets the system pressure difference which is more than the four-way valve reversing target pressure difference delta P;
monitoring whether the water outlet temperature of the air conditioning unit meets the water outlet temperature which is more than the minimum tolerable water outlet temperature T of defrosting 2 ；
It is monitored whether the compressor of the air conditioning unit has been running for more than N minutes.
In a specific embodiment, the invention directly introduces the refrigerant at the exhaust port of the compressor of the air conditioning unit into the refrigerant pipe of the fin of the evaporator in the frost suppression mode, thereby melting the thinner frost layer on the fin.
In a specific embodiment, the defrosting preparation mode of the present invention includes the following steps, and the following steps are not in obvious sequence.
Loading the compressor to be full in a preset loading time period;
the main throttle element is opened to a target opening X;
adjusting the target temperature of the water outlet to the target water temperature T of defrosting preparation m 。
In a specific embodiment, the heating energy efficiency ratio decreasing amplitude of the invention is obtained by dividing the value of the COP after the last defrosting is finished and the COP after the heating is finished for m minutes by the COP at the current time after the last defrosting is finished and the COP after the heating is finished for m minutes.
In the prior art, COP is generally obtained by dividing capacity by power, that is, cop=capacity/power, COP is an important index for measuring running performance of a unit, when the unit normally runs, fins are not frosted, a fan normally runs, COP can be maintained at a satisfactory threshold, but after frosting occurs on fins on a condensing side of the unit, frost layers on the outer layers of the fins lead to difficult air intake, cooling capacity of the unit is reduced due to insufficient heat exchange on the condensing side, meanwhile, the unit with insufficient heat exchange on the condensing side can be used for increasing fan frequency to meet heat exchange requirements, but because the thicker the frost layers are, even if the fan frequency is increased, the phenomenon that the fan frequency is increased is not supplemented is caused, so that the COP of the unit is greatly reduced.
Although COP can effectively reflect the condition of a unit, for a large air-cooled unit, it is very difficult to accurately measure the actual refrigerating capacity or heating capacity, because a large engineering site cannot be equipped with a power meter and a device for detecting the unit capacity, the invention provides a method for calculating COP, the COP is calculated by adopting a formula cop=α pressure ratio+β evaporation temperature- γ water inlet temperature+δ water inlet and outlet temperature difference+η, parameters used in the formula can be easily measured on the engineering site, and thus the corresponding COP can be accurately calculated, and coefficients α, β, δ and η used in the formula can be obtained by corresponding data fitting.
The frost control method can be used for finding that the fins have slight frosting and performing frost control through the calculation of the reduction amplitude of the heating energy efficiency ratio in the early monitoring stage, can maintain the unit maintaining capability and performance operation for a period of time, and immediately switches the defrosting mode when the frost control cannot be met.
Fig. 9 shows a specific embodiment of the present invention, which is described in detail below.
And the machine set is started by heating and then is initially operated for M time, and defrosting condition detection is not carried out in the M time, so that the phenomenon that the machine set system is unstable in operation and identification errors enter defrosting during initial starting is avoided.
After the M time length, the unit enters a frosting inhibition detection step, and the heating energy efficiency ratio reduction amplitude delta COP is detected.
The detection is a starting step of inhibiting defrosting, and continuously monitors the decrease of the heating energy efficiency ratio by delta COP.
The heating energy efficiency ratio is reduced within the beta time to be larger than COP x1 -1, turning on the defrost mode while entering the defrost preparation mode.
After the frost suppression mode is turned on, the bypass valve 7 is opened. And simultaneously monitoring defrosting conditions in real time.
After the frost suppression mode is started, the delta COP monitoring data are emptied and re-monitored (the mode aims at slowing down the frost formation speed and melting the primary frost layer to a certain extent, and the operation of the unit is not affected).
In the process of the frost inhibition mode, when the heating energy efficiency ratio is monitored to be reduced within the beta time, the delta COP is always smaller than the COP x1 -1, indicating that the energy efficiency of the unit is restored, closing the frost suppression mode, closing the bypass valve 7, and simultaneously closing the defrosting preparation mode.
In the process of the frost suppression mode, if the heating energy efficiency ratio is monitored to be reduced by a certain degree delta COP which is larger than a preset value COP x1 -1, the preset value, also called the defrosting energy efficiency ratio of only wanted value, maintains the defrosting mode and monitors the defrosting conditions in real time.
If the defrosting mode is operated continuously for S minutes, and the monitoring value of the heating energy efficiency ratio decreasing amplitude delta COP does not reach the condition of closing the defrosting mode, the defrosting mode is directly opened, the defrosting mode is closed, and the bypass valve is closed.
The starting defrosting preparation mode of the embodiment mainly modulates the unit to a defrosting preparation state. The compressor can be rapidly loaded to full load; the main throttle element is opened to a target opening X; automatically adjusts the water temperature of the water outlet target to the water temperature T of the defrosting preparation target m 。
The present embodiment monitors the defrosting conditions including the following aspects.
(1) Monitoring whether DeltaCOP > COP is met x1 -1；
(2) Continuously detecting whether the suction pressure is less than or equal to a P set value or not in theta seconds;
(3) monitoring whether the accumulated running time (compressor starting time) t of the compressor is more than defrosting interval setting time t1;
(4) monitoring whether the defrosting temperature detected by the defrosting temperature sensing bulb for 60 seconds continuously is less than or equal to the defrosting start setting temperature T 1 ；
(5) Monitoring whether the system pressure difference is more than four-way valve reversing target pressure difference delta P (the system pressure difference is the value of the high pressure minus the low pressure of the compressor);
(6) monitoring air conditioner water outlet temperature > defrosting minimum bearable water outlet temperature T 2 ；
(7) It is monitored whether the compressor has been running for more than N minutes.
If the defrosting conditions are met, and the water outlet temperature of the unit is greater than or equal to the defrosting preparation target water temperature T m The defrost mode is turned on.
If the monitoring unit does not meet the defrosting condition and the defrosting mode is closed, the unit is in a frostless state after the normal running state of the unit is restored, and the defrosting preparation state is closed.
And starting a defrosting mode, and detecting defrosting exit conditions in real time, wherein the exit conditions are as follows.
(1) Monitoring whether defrosting time T is met h Duration of defrosting set time T t 。
(2) Monitoring whether the defrosting temperature of the continuous f-second detection system is more than the defrosting end setting temperature T j 。
(3) Monitoring whether high pressure continuous Y seconds > defrosting exit pressure F is satisfied.
And after the time M is reached, the unit operates stably, and the defrosting mode is started.
The invention judges whether the unit needs to inhibit frost by detecting COP change of the air-cooled heat pump unit, comprehensively controls the switching between the heating state and the defrosting state of the unit by the frosting state of the unit and the influence on the performance of the unit, and can effectively solve the problems of frostless, frosted, inaccurate defrosting time of the traditional air-cooled heat pump unit.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (11)
1. The frost control method of the air-cooled unit of the air conditioner is characterized by comprising the following steps:
after the machine set is started for a period of time, calculating the reduction amplitude of the heating energy efficiency ratio;
when the reduction amplitude of the heating energy efficiency ratio is always larger than a preset value within a certain period of time, starting a defrosting mode and a defrosting preparation mode while the unit continues heating; in the process of performing the defrosting mode and the defrosting preparation mode, the descending amplitude of the heating energy efficiency ratio is calculated, and the operation mode of the unit is switched according to the descending amplitude of the heating energy efficiency ratio, or the operation mode of the unit is switched after corresponding judging conditions are selected.
2. The method for controlling frost in an air-cooled unit of an air conditioner according to claim 1, wherein the frost suppressing mode and the defrosting preparation mode are closed and the conventional heating mode is entered if the decrease in heating energy efficiency ratio is always smaller than a preset value for a certain period of time during the defrosting mode and the defrosting preparation mode.
3. The method for controlling the frost of an air-cooled unit of an air conditioner according to claim 1, wherein if the decrease of the heating energy efficiency ratio is greater than a preset value during the frost suppressing mode and the defrosting preparation mode, the frost suppressing mode and the defrosting preparation mode are maintained, the defrosting condition is monitored in real time, and the operation duration of the frost suppressing mode is counted;
when the defrosting condition is met and/or the operation duration of the defrosting mode is greater than or equal to the preset duration, if defrosting preparation is finished at the moment, heating is suspended, and defrosting is started.
4. The method for controlling frost of an air-cooled unit of an air conditioner according to claim 3, wherein when the defrosting condition and/or the operation duration of the defrosting mode are/is greater than or equal to a preset duration, if defrosting preparation is still underway at this time, waiting for defrosting preparation, suspending heating, and starting defrosting.
5. The method for controlling frost of an air-cooled unit of an air conditioner as set forth in claim 3, wherein the monitoring of the defrosting condition includes:
monitoring whether the reduction amplitude of the heating energy efficiency ratio is larger than a preset value;
monitoring whether the continuous theta-second suction pressure meets the suction pressure less than or equal to a set value P;
monitoring whether the accumulated running time of the compressor meets the accumulated running timet is more than the defrosting interval setting time t1; monitoring whether the defrosting temperature detected by the defrosting temperature sensing bulb for 60 seconds continuously is less than or equal to the defrosting start setting temperature T 1 ；
Monitoring whether the system pressure difference meets the system pressure difference which is more than the four-way valve reversing target pressure difference delta P;
monitoring whether the water outlet temperature of the unit meets the water outlet temperature which is more than the minimum tolerable water outlet temperature T of defrosting 2 ；
It is monitored whether the compressor of the unit has been running for more than N minutes.
6. The method for controlling frost of an air-cooled unit of an air conditioner as set forth in claim 1, wherein the frost suppressing mode includes the steps of: and directly introducing the refrigerant at the exhaust port of the compressor of the unit into the fin refrigerant pipe of the evaporator.
7. The method for controlling frost of an air-cooled unit of an air conditioner as set forth in claim 1, wherein the defrosting preparation mode includes the steps of:
loading the compressor to be full in a preset loading time period;
the main throttle element is opened to a target opening X;
adjusting the target temperature of the water outlet to the target water temperature T of defrosting preparation m 。
8. The method for controlling frost of an air-cooled unit for an air conditioner according to any one of claims 1 to 7, wherein the decrease in heating energy efficiency ratio is obtained by dividing a value obtained by subtracting a COP at a current time from a COP after the last defrosting is completed and after the last defrosting is completed by m minutes after the last defrosting is completed
COP after minutes was obtained.
9. The method for controlling frost of an air-cooled unit of an air conditioner according to claim 8, wherein the COP is calculated by using a formula COP = α pressure ratio + β evaporation temperature- γ water inlet temperature + δ water inlet and outlet temperature difference +η.
10. An air-cooled air conditioner unit comprising a controller, wherein the controller adopts the frost control method of the air-cooled air conditioner unit according to any one of claims 1 to 9 when the unit heats.
11. The air-cooled unit of claim 10, further comprising: a main circulation flow path including a compressor, an air side heat exchanger, a water side heat exchanger, a main throttling element, a four-way valve;
and one end of the bypass branch is connected with the refrigerant inlet of the water side heat exchanger, and the other end of the bypass branch is connected with the fin refrigerant pipe of the air side heat exchanger.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311676178.3A CN117628641A (en) | 2023-12-07 | 2023-12-07 | Air-cooled unit of air conditioner and frost control method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311676178.3A CN117628641A (en) | 2023-12-07 | 2023-12-07 | Air-cooled unit of air conditioner and frost control method thereof |
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| CN117628641A true CN117628641A (en) | 2024-03-01 |
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| CN202311676178.3A Pending CN117628641A (en) | 2023-12-07 | 2023-12-07 | Air-cooled unit of air conditioner and frost control method thereof |
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- 2023-12-07 CN CN202311676178.3A patent/CN117628641A/en active Pending
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