CN110715481A - Defrosting method of air source heat pump unit - Google Patents
Defrosting method of air source heat pump unit Download PDFInfo
- Publication number
- CN110715481A CN110715481A CN201910815218.5A CN201910815218A CN110715481A CN 110715481 A CN110715481 A CN 110715481A CN 201910815218 A CN201910815218 A CN 201910815218A CN 110715481 A CN110715481 A CN 110715481A
- Authority
- CN
- China
- Prior art keywords
- defrosting
- temperature
- air
- less
- condition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
- F25B47/02—Defrosting cycles
- F25B47/022—Defrosting cycles hot gas defrosting
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Defrosting Systems (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention relates to the technical field of air source heat pumps, in particular to a defrosting method of an air source heat pump unit, which calculates a defrosting accumulated running time difference t of a refrigerant circulating system which does not meet defrosting entry conditions and the refrigerant circulating system which meets the defrosting entry conditionsDComparing the defrosting cumulative operation time tDAnd a first preset time t0Wherein t is0And if the defrosting condition is more than 0, judging whether the refrigerant circulating system which does not meet the defrosting entering condition enters the defrosting process or not, and effectively avoiding wrong defrosting and excessive defrosting.
Description
Technical Field
The invention relates to the technical field of air source heat pumps, in particular to a defrosting method of an air source heat pump unit.
Background
The air source heat pump unit is used as air conditioning equipment which can supply cold and heat, and the used regions are very wide, so that the facing climate environment is complicated and frosting situations are numerous. The frosting seriously affects the heat exchange efficiency of the air side heat exchanger, so that the heating capacity and the energy efficiency ratio are attenuated, and when a unit is in heating operation, the defrosting operation is needed after a frost layer is accumulated to a certain degree.
A multi-system air source heat pump unit refers to a heat pump unit, which is provided with 2 or more than 2 refrigerant circulating systems.
When the air flow channels of the fans used in the air-side heat exchangers of multiple systems are communicated with each other, such designs are called "shared air" systems, and such units generally defrost by means of synchronous defrosting (defrosting is performed by starting a refrigeration mode). Synchronous defrosting refers to that when any system in a unit meets the defrosting entering condition, the other systems of the unit simultaneously enter defrosting operation. Because the defrosting process needs to close the fan of the system, the fan is prevented from radiating heat to the environment, and the heat of the defrosting operation system needs to be ensured to be transferred to the frost layer on the surface of the air side heat exchanger, so that the defrosting action is completed more quickly, when 1 system operates and defrosts, the fan is closed, and other systems of the 'shared air' unit cannot perform normal heating operation (the fan needs to operate), so that the synchronous defrosting mode is adopted.
When the shared air type unit is operated under a non-full load, heating operation time lengths among different systems are possibly different, synchronous defrosting of the unit can cause that one or more systems are in a 'wrong defrosting' action of defrosting without meeting defrosting entering conditions, and the unit is actually operated in a refrigerating mode during defrosting, so that excessive loss and waste of heat are caused, and the comprehensive heating energy efficiency ratio of the air conditioning system is reduced.
When the air circulation channels of the fans used by the air-side heat exchangers of the multiple systems are independent of each other, the design is called as an independent air system, and the units are usually defrosted in an asynchronous defrosting mode. Asynchronous defrosting refers to that when any system in a unit meets a defrosting entering condition, the system enters defrosting operation, a fan of the system is turned off, but other systems of the unit still operate to heat, and the fan is not stopped.
When the independent air type unit is in full-load operation, the heating operation time lengths among different systems are the same or very close to each other, so that the frosting conditions of the surfaces of the air side heat exchangers of the systems are approximate, but at the moment, the control program still forces the systems to execute asynchronous defrosting, and multiple defrosting actions, namely 'excess defrosting', of the unit can occur in a short time range, so that excessive loss and waste of heat are caused, and the comprehensive heating energy efficiency ratio of the air conditioning system is reduced.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a defrosting method of an air source heat pump unit, which is beneficial to saving heat and improving the comprehensive energy efficiency of the air source heat pump unit.
In order to achieve the purpose, the invention adopts the following technical scheme:
a defrosting method of an air source heat pump unit comprises at least two sets of refrigerant circulating systems, wherein each set of refrigerant circulating system comprises an air side heat exchanger which is a fin heat exchanger; the defrosting method comprises the following steps:
step one, determining a refrigerant circulating system meeting defrosting entry conditions;
step two, calculating the difference value t between the defrosting accumulated running time of a certain set of refrigerant circulating system which does not meet the defrosting entering condition and the defrosting accumulated running time of the refrigerant circulating system which meets the defrosting entering conditionD；
Step three, comparing the defrosting accumulated running time difference tDAnd a first preset time t0Wherein t is0＞0：
If the defrosting operation time difference t is accumulatedDNot more than first preset time t0If the defrosting condition is satisfied, the set of refrigerant circulating system which does not satisfy the defrosting entering condition and the set of refrigerant circulating system which satisfies the defrosting entering condition both enter the defrosting process;
if the defrosting operation time difference t is accumulatedDIs greater than a first preset time t0The refrigerant cycle system satisfying the defrosting entry condition enters the defrosting process, and the set of refrigerant cycles not satisfying the defrosting entry conditionThe ring system is stopped to wait or continues to work normally;
and step four, repeating the step two and the step three, and judging whether all the refrigerant circulating systems which do not meet the defrosting entering condition can enter the defrosting process.
Preferably, 5min is less than or equal to the first preset time t0≤30min。
Preferably, in step three, if defrosting, the accumulated running time difference t isDNot more than first preset time t0Then, the evaporating temperature difference DeltaT of the set of the refrigerant cycle system which does not satisfy the defrosting entry condition is calculatedeDifference in evaporating temperature Δ TeIs the difference value between the current evaporation temperature of the set of the refrigerant circulating system and the evaporation temperature required by the set of the refrigerant circulating system to enter the defrosting process, if the difference value of the evaporation temperatures is delta TeNot more than first preset temperature T0First predetermined temperature T0If the temperature is more than 0, the refrigerant circulating system enters a defrosting process; if the difference of evaporation temperature is Delta TeGreater than a first predetermined temperature T0If the defrosting condition is satisfied, the refrigerant circulation system which does not satisfy the defrosting condition is stopped to wait or normally works.
Preferably, in step three, if defrosting, the accumulated running time difference t isDNot more than first preset time t0Then the current evaporating temperature T of the set of refrigerant cycle system which does not satisfy the defrosting entry condition is calculatedeAnd the current evaporation temperature TeThe set of the refrigerant circulating system enters a defrosting process when the following conditions are met: when the ambient temperature T of the environment where the air side heat exchanger of the set of refrigerant cycle system does not meet the defrosting entry conditionair< second predetermined temperature T1 and Te＜(K1*Tair-A1) + B1, or when the ambient temperature T isairNot less than a second predetermined temperature T1 and Te＜(K2*Tair-a2) + B2; wherein T1 is more than-8 ℃ and less than 0 ℃, K1 is more than or equal to 0.5 and less than or equal to 0.9, A1 is more than 10 and less than 20, B1 is more than 0 and less than 2, K2 is more than or equal to 0.6 and less than or equal to 1.2, A2 is more than 11 and less than 19, and B2 is more than 0 and less than 2;
if the current evaporation temperature T of the set of refrigerant circulating system does not meet the defrosting entry conditioneIf the above condition is not satisfied, thenWhen the refrigerant circulating system meeting the defrosting entry condition enters the defrosting process, the set of refrigerant circulating system not meeting the defrosting entry condition works normally or stops for waiting.
Preferably, the second preset temperature T1 is-4 ℃, K1 ═ 0.7, a1 ═ 13, B1 ═ 1, K2 ═ 0.8, a2 ═ 12, and B2 ═ 1.
Preferably, the defrosting cumulative operating time is calculated as follows,
wherein, the starting timing condition is as follows: after the refrigerant circulating system is heated and started for the first time or after the defrosting process is finished and the heating and starting are recovered, the refrigerant circulating system is started from the evaporating temperature TeTiming is started when the temperature is less than the third preset temperature T2, wherein the temperature is less than minus 7 ℃ and less than the third preset temperature T2 and less than 3 ℃;
if during the time course, the evaporation temperature TeThe time is cleared when the temperature is equal to or more than the third preset temperature T2 and the duration is more than T1, wherein T1 is equal to or more than 30s, and the temperature is at the evaporation temperature TeRestarting timing at the moment of being less than the third preset temperature T2;
if the refrigerant circulating system is stopped in the timing process, the timing is stopped and the zero clearing is not carried out, the refrigerant circulating system is started again, the running time is more than or equal to the time T3, the time T3 is more than 0, and if the evaporation temperature T is higher than or equal to the evaporation temperature TeThe time is reset when the temperature is equal to or more than the third preset temperature T2 and the duration time is more than T1, and the temperature is at the evaporating temperature TeRestarting timing at the moment of being less than the third preset temperature T2; if the refrigerant circulating system is stopped in the timing process, the timing is stopped and is not cleared, the refrigerant circulating system is started again, the running time is not less than T3, and if the evaporation temperature T is lower than TeIf the temperature is less than the third preset temperature T2, the timing is accumulated, and only the evaporation temperature T is accumulatede< time of the third preset temperature T2.
Preferably, the defrost entry conditions are: condition A, ambient temperature TairNot more than first preset environmental temperature T0airAnd the first preset environmental temperature T0 is less than or equal to 5 DEG CairLess than or equal to 15 ℃; the condition B is that the accumulated defrosting operation time is more than or equal to the defrosting period T; condition C, ambient temperature TairTemperature T of finfIs less than a fourth preset temperature T3Fourth predetermined temperature T3Is greater than 0; the condition D is that the number of the refrigerant circulating systems in the defrosting process is less than the number N of the allowable defrosting systems of the air source heat pump unit, N is more than 0 and less than or equal to the number of the refrigerant circulating systems in the air source heat pump unit, and N is an integer; condition E, Module Water out temperature TWONot less than the preset module water outlet temperature T0WOAnd the preset module water outlet temperature T0 is less than or equal to 5 DEG CWOThe temperature is less than or equal to 15 ℃, and the module is an air source heat pump unit.
Preferably, the defrost entry conditions are:
condition A, ambient temperature TairNot more than first preset environmental temperature T0airAnd the first preset environmental temperature T0 is less than or equal to 5 DEG Cair≤15℃；
The condition B is that the accumulated defrosting operation time is more than or equal to the defrosting period T;
condition C, at ambient temperature Tair< second preset ambient temperature T1airA second preset ambient temperature T1 of not less than 10 DEG CairNot more than 0, evaporation temperature Te< K1 ambient temperature Tair-C0, and duration tc0Wherein K1 is more than or equal to 0.5 and less than or equal to 0.9, CO is more than 10 and less than 20, tc0Is more than 0 s; or when the ambient temperature TairNot less than second preset environmental temperature T1airA second preset ambient temperature T1 of not less than 10 DEG CairNot more than 0, evaporation temperature Te< K2 ambient temperature Tair-C1, and duration tc1Wherein K2 is more than or equal to 0.6 and less than or equal to 1.2, C1 is more than 9 and less than 19, and tc1＞0s；
The condition D is that the number of the refrigerant circulating systems in the defrosting process is less than the number N of the allowable defrosting systems of the air source heat pump unit, N is more than 0 and less than or equal to the number of the refrigerant circulating systems of the air source heat pump unit, and N is an integer;
condition E, the module outlet water temperature is more than or equal to the preset module outlet water temperature T0WOAnd the preset module water outlet temperature T0 is less than or equal to 5 DEG CWOThe temperature is less than or equal to 15 ℃, and the module is an air source heat pump unit.
Preferably, the defrosting period T is 30min, and the first preset environment temperature T0airThe temperature is 10 ℃, N is half of the number of refrigerant circulating systems in the air source heat pump unit, and the outlet water temperature T0 of the module is presetWOIs 10 ℃.
Preferably, in the condition A, the first preset ambient temperature T0airIs 10 ℃; in the condition B, the defrosting period T is 30 min; in condition C, the second preset ambient temperature T1airAt a temperature of-4 ℃ tc0＝120s，tc1120s, 0.7 for K1, 13 for C0, 12 for C1, 0.8 for K2; in the condition D, the number N of the allowable defrosting systems is half of the number of the refrigerant circulating systems in the air source heat pump unit; in condition E, the module outlet water temperature T0 is presetWOIs 10 ℃.
Preferably, comprises M0Refrigerant circulating system, M0Is an integer greater than 2; if the air source heat pump unit has M in the same moment1The refrigerant circulating system meets the defrosting entry condition, M12 or more and less than the total number of the refrigerant circulating systems; in the second step, the difference value t between the defrosting accumulated operation time of a certain set of refrigerant circulation system which does not meet the defrosting entry condition and the refrigerant circulation system which meets the defrosting entry condition and has the shortest defrosting accumulated operation time is calculatedD。
The defrosting method of the air source heat pump unit is characterized in that the accumulated running time difference t is calculated according to defrostingDAnd a first preset time t0If the defrosting operation is performed, the difference t is calculatedDIs greater than a first preset time t0If so, the heating operation time lengths of the set of refrigerant circulating system which does not meet the defrosting entry condition and the set of refrigerant circulating system which meets the defrosting entry condition are greatly different, and at the moment, the set of refrigerant circulating system which does not meet the defrosting entry condition does not enter the defrosting process, but stops for waiting or normally works, so that the error defrosting of the refrigerant circulating systems (the systems with shorter heating operation time) is avoided, the waste and the loss of heat are avoided, and the comprehensive energy efficiency of the air source heat pump unit is improved; if the defrosting operation time difference t is accumulatedDNot more than first preset time t0When the heating operation time of the refrigerant circulation system not meeting the defrosting entry condition is relatively close to that of the refrigerant circulation system meeting the defrosting entry condition, the frosting condition of the surface of the air side heat exchanger is relatively close to that of the refrigerant circulation system meeting the defrosting entry condition, and the defrosting entry condition is not metThe refrigerant circulating systems also jointly enter the defrosting process, so that the times of the air source heat pump unit entering the defrosting process can be effectively reduced, the heat waste and loss caused by multiple and continuous defrosting processes are avoided, and the comprehensive energy efficiency of the air source heat pump unit is improved. In addition, the defrosting entering condition can accurately judge the frosting condition of the surface of the air side heat exchanger, so that the air side heat exchanger enters the defrosting process at an accurate time, the heat is saved, and the comprehensive energy efficiency of the air source heat pump unit is improved.
Drawings
FIG. 1 is a schematic view of an air source heat pump unit according to the present invention, in which each compressor is connected to an air-side heat exchanger, and different air-side heat exchangers share a fan and are communicated with a ventilation channel;
FIG. 2 is another schematic structural view of the air source heat pump unit of the present invention, wherein each compressor is connected to two air-side heat exchangers, and different air-side heat exchangers share a fan and are communicated with a ventilation channel;
FIG. 3 is a schematic structural diagram of an air source heat pump unit of the present invention, which is the same as the air source heat pump unit of FIG. 1, and is in a defrosting process;
FIG. 4 is a schematic structural diagram of an air source heat pump unit of the present invention, which is the same as the air source heat pump unit of FIG. 2, and is in a defrosting process;
FIG. 5 is a schematic view of a third construction of the air source heat pump unit of the present invention, in which different air side heat exchangers use different fans and the ventilation channels of the different air side heat exchangers are isolated from each other;
FIG. 6 is the same as the air source heat pump unit shown in FIG. 5, in an asynchronous defrosting operation;
FIG. 7 is a schematic view showing an embodiment of a defrosting method of an air source heat pump unit according to the present invention, in which air side heat exchangers share a blower and ventilation passages are communicated;
FIG. 8 is a schematic view showing an embodiment of a defrosting method of an air source heat pump unit according to the present invention, in which each air-side heat exchanger uses a different blower and the respective ventilation channels are isolated from each other;
FIG. 9 is a view showing an embodiment of a defrosting method of the air source heat pump unit according to the present invention, which is a modified embodiment of the defrosting method shown in FIG. 7;
FIG. 10 is a view showing an embodiment of a defrosting method of the air source heat pump unit according to the present invention, which is a modified embodiment of the defrosting method shown in FIG. 8;
FIG. 11 is a graph showing a simulation process of the present invention with a synchronous defrosting operation during partial load operation of the air source heat pump unit with a dual refrigerant circulation system;
FIG. 12 is a graph showing a simulation process using asynchronous defrosting in partial load operation of the air source heat pump unit with dual refrigerant circulation systems and shared air according to the present invention;
FIG. 13 is a graph showing a simulation process using asynchronous defrosting in partial load operation of the air source heat pump unit with dual refrigerant circulation systems and independent air of the present invention;
FIG. 14 is a simulation curve of the air source heat pump unit with dual refrigerant circulation systems, independent air or shared air, during full-load operation, with synchronous defrosting.
Detailed Description
The following describes a specific embodiment of the defrosting method of the air source heat pump unit according to the present invention with reference to the embodiments shown in fig. 1 to 14. The defrosting method of the air source heat pump unit of the present invention is not limited to the description of the following embodiments.
The defrosting method of the air source heat pump unit comprises the steps that the air source heat pump unit comprises at least two sets of refrigerant circulating systems, each set of refrigerant circulating system comprises an air side heat exchanger, and the air side heat exchanger is a fin heat exchanger; the defrosting method comprises the following steps:
step one, determining a refrigerant circulating system meeting defrosting entry conditions;
step two, calculating the difference value t between the defrosting accumulated running time of a certain set of refrigerant circulating system which does not meet the defrosting entering condition and the defrosting accumulated running time of the refrigerant circulating system which meets the defrosting entering conditionD；
Step three, comparing the defrosting accumulated operationDifference of line time tDAnd a first preset time t0Wherein t is0＞0：
If the defrosting operation time difference t is accumulatedDNot more than first preset time t0If the defrosting condition is satisfied, the set of refrigerant circulating system which does not satisfy the defrosting entering condition and the set of refrigerant circulating system which satisfies the defrosting entering condition both enter the defrosting process;
if the defrosting operation time difference t is accumulatedDIs greater than a first preset time t0If so, the refrigerant circulating system meeting the defrosting entry condition enters the defrosting process, and the set of refrigerant circulating system not meeting the defrosting entry condition stops to wait or continues to work normally;
and step four, repeating the step two and the step three, and judging whether all the refrigerant systems which do not meet the defrosting entering condition can enter the defrosting process.
The defrosting method of the air source heat pump unit is characterized in that the accumulated running time difference t is calculated according to defrostingDAnd a first preset time t0If the defrosting operation is performed, the difference t is calculatedDIs greater than a first preset time t0If so, the heating operation time lengths of the set of refrigerant circulating system which does not meet the defrosting entry condition and the set of refrigerant circulating system which meets the defrosting entry condition are greatly different, and at the moment, the set of refrigerant circulating system which does not meet the defrosting entry condition does not enter the defrosting process, but stops for waiting or normally works, so that the error defrosting of the refrigerant circulating systems (the systems with shorter heating operation time) is avoided, the waste and the loss of heat are avoided, and the comprehensive energy efficiency of the air source heat pump unit is improved; if the defrosting operation time difference t is accumulatedDNot more than first preset time t0Explaining that the set of refrigerant circulating system which does not meet the defrosting entry condition and the set of refrigerant circulating system which meets the defrosting entry condition have relatively close heating operation time, the frosting condition of the surface of the air side heat exchanger is relatively close, and the set of refrigerant circulating system which does not meet the defrosting entry condition also enters the defrosting process together, thereby effectively reducing the frequency of the air source heat pump unit entering the defrosting process, avoiding the heat waste and loss caused by multiple and continuous defrosting processes,the comprehensive energy efficiency of the air source heat pump unit is improved.
Preferably, the air source heat pump unit comprises M0Refrigerant circulating system, M0Is an integer greater than 2; if the air source heat pump unit has M in the same moment1The refrigerant circulating system meets the defrosting entry condition, M1Not less than 2 and less than the total number of the refrigerant circulating systems, in the second step, the defrosting accumulated operation time difference t between a certain set of refrigerant circulating systems which do not meet the defrosting entry condition and the refrigerant circulating system which meets the defrosting entry condition and has the shortest defrosting accumulated operation time is calculatedD. For example, the air source heat pump unit comprises 6 sets (namely M)06) refrigerant circulation systems, i.e., a system a, a system B, a system C, a system D, a system E, and a system F, respectively; at a certain moment, the system A, the system B and the system C simultaneously meet the defrosting entrance condition (namely M)13) of the defrosting operation time difference, and respectively calculating the defrosting operation time difference t between the defrosting operation time of the system D, the defrosting operation time of the system E and the defrosting operation time of the system F and the defrosting operation time of the system A when the relationship of the defrosting operation time of the system A < the system B < the system C is that the defrosting operation time of the system D, the defrosting operation time of the system E and the defrosting operation time of theD。
For example, as shown in fig. 11, the air source heat pump unit includes two refrigerant circulation systems, which are a system 1 and a system 2, the system 1 operates for a long time, and the system 2 alternately operates and is in a shutdown state, so that the output capacity of the whole air source heat pump unit is controlled to be 50-100%, the air source heat pump unit is in a partial load operation state, when the system 1 needs defrosting, the time for operating the system 2 is short, defrosting is not needed, and meanwhile, the system 1 and the system 2 are defrosted, for the system 2, for the operation of 'defrosting by mistake', heat loss of the air source heat pump unit is caused, and the comprehensive heating energy efficiency ratio is reduced.
As shown in fig. 12, the air source heat pump unit includes two refrigerant circulation systems, i.e., a system 1 and a system 2, which belong to a "shared air" type, and the defrosting method of the air source heat pump unit of the present invention is adopted, when the system 1 is defrosted, the system 2 is stopped to wait, and when the system 2 is defrosted, the system 1 is stopped to wait, so that the "wrong defrosting" operation of the refrigerant circulation system which does not satisfy the defrosting entry condition is avoided. As shown in fig. 13, the air source heat pump unit includes two refrigerant circulation systems, i.e., a system 1 and a system 2, which are independent air types, and by using the defrosting method of the air source heat pump unit of the present invention, when the system 1 is defrosted, the system 2 is normally operated, and when the system 2 is defrosted, the system 1 is normally operated. Referring to fig. 12 and 13, for two types of air source heat pump units, when the air source heat pump units are in a partial load operation state, the air source heat pump unit defrosting method of the present invention is adopted, so that asynchronous defrosting of the system 1 and the system 2 is realized, and defrosting times of the air source heat pump units can be reduced within a certain time range, thereby improving the heating comprehensive energy efficiency ratio of the air source heat pump units.
As shown in fig. 14, the air source heat pump unit includes two refrigerant circulation systems, i.e., a system 1 and a system 2, both the system 1 and the system 2 operate for a long time, the whole air source heat pump unit is in a full-load operation state, frost layers on surfaces of air side heat exchangers of the air source heat pump unit and the system 2 are relatively close to each other, and accumulated defrosting operation time of the air source heat pump unit and the system 2 is also relatively close to each other.
Preferably, the time is less than or equal to 5min and less than or equal to a first preset time t0Less than or equal to 30 min. Further, the first preset time t0It is 10 min. Of course, according to the actual situation, the first preset time t0Can be adjusted, for example, for a first predetermined time t0Any time between 0 and 30min is possible.
Preferably, in step three, if defrosting, the accumulated running time difference t isDNot more than first preset time t0Then the current evaporating temperature T of the set of refrigerant cycle system which does not satisfy the defrosting entry condition is calculatedeAnd the current evaporation temperature TeThe suit of the condition that the defrosting entry condition is not satisfied is satisfiedThe refrigerant circulating system enters a defrosting process: when the defrosting entry condition is not satisfied, the ambient temperature T of the environment in which the air-side heat exchanger of the refrigerant cycle system is locatedair< second predetermined temperature T1 and Te＜(K1*Tair-A1) + B1, or when the ambient temperature T isairNot less than a second predetermined temperature T1 and Te＜(K2*Tair-a2) + B2; wherein T1 is more than-8 ℃ and less than 0 ℃, K1 is more than or equal to 0.5 and less than or equal to 0.9, A1 is more than 10 and less than 20, B1 is more than 0 and less than 2, K2 is more than or equal to 0.6 and less than or equal to 1.2, A2 is more than 11 and less than 19, and B2 is more than 0 and less than 2; if the current evaporation temperature T of the set of refrigerant circulating system does not meet the defrosting entry conditioneIf the condition is not met, the refrigerant circulating system meeting the defrosting entry condition normally works or stops to wait when the refrigerant circulating system meeting the defrosting entry condition enters the defrosting process. Further, the second preset temperature T1 is-4 ℃, K1 is 0.7, a1 is 13, B1 is 1, K2 is 0.8, a2 is 12, and B2 is 1.
Fig. 7 shows a first embodiment of the defrosting method of the air source heat pump unit according to the present invention.
The air source heat pump unit comprises at least two refrigerant circulating systems and a control system connected with the refrigerant circulating systems, and is of a 'shared air' type (namely, as shown in figures 1-4, the air side heat exchangers of the refrigerant circulating systems use the same group of fans, and air circulation channels of the fans are communicated with each other); each refrigerant circulating system comprises an air side heat exchanger which is a fin heat exchanger; the defrosting method comprises the following steps:
step one, determining a refrigerant circulating system meeting defrosting entry conditions;
for the same air source heat pump unit, only one set of refrigerant circulating system meets the defrosting entry condition at the same time.
Step two, the control system calculates the defrosting accumulated operation time running difference t of the defrosting accumulated operation time of the refrigerant circulating system meeting the defrosting entering condition and the defrosting accumulated operation time of one set of refrigerant circulating system not meeting the defrosting entering conditionD。
Step three, comparing the defrosting accumulated operationDifference of line time tDAnd a first preset time t0Wherein the first preset time t0＞0：
If the defrosting operation time difference t is accumulatedDNot more than first preset time t0If the defrosting condition is satisfied, the set of refrigerant circulating system which does not satisfy the defrosting entry condition and the set of refrigerant circulating system which satisfies the defrosting entry condition both enter the defrosting process;
if the defrosting operation time difference t is accumulatedDIs greater than a first preset time t0If so, the refrigerant circulating system meeting the defrosting entry condition enters the defrosting process, and the set of refrigerant circulating system not meeting the defrosting entry condition stops waiting.
And step four, repeating the step two and the step three to judge whether each set of refrigerant circulating system which does not meet the defrosting entering condition can enter the defrosting process.
Preferably, the first preset time t0It is 10 min.
Preferably, a method for calculating the defrosting cumulative operating time is as follows:
starting timing conditions: after the refrigerant circulating system is heated and started for the first time or after the defrosting process is finished and the heating and starting are recovered, the refrigerant circulating system is started from the evaporating temperature Te< third preset temperature T2 (i.e., evaporating temperature T)eThe time when the temperature is reduced to be lower than the third preset temperature T2), timing is started, wherein the temperature is lower than minus 7 ℃ and lower than the third preset temperature T2 and lower than 3 ℃; if during the time course, the evaporation temperature TeThe time is reset when the temperature is equal to or more than the third preset temperature T2 and the duration is more than T1, and T1 is equal to or more than 30s, and the temperature is set at the evaporation temperature TeRestarting timing at the moment of being less than the third preset temperature T2; if the refrigerant circulating system is stopped in the timing process, the timing is stopped and is not cleared, the refrigerant circulating system is started again, the running time is more than or equal to the time T3, T3 is more than 0, and if the evaporation temperature T is higher than or equal to the evaporation temperature TeThe time is reset when the temperature is equal to or more than the third preset temperature T2 and the duration time is more than T1, and the temperature is at the evaporating temperature TeRestarting timing at the moment of being less than the third preset temperature T2; if the refrigerant circulating system is stopped in the timing process, the timing is stopped and is not cleared, and the refrigerant circulating system is restartedAfter the starting and the running time is more than or equal to the time T3, T3 is more than 0, if the evaporation temperature T iseIf the temperature is less than the third preset temperature T2, the timing is accumulated, and only the evaporation temperature T is accumulatede< time of the third preset temperature T2. Further, the third preset temperature T2 is-2 ℃, the time T1 is 60s, and the time T3 is 2 min.
Preferably, a first predetermined time t0The determination method comprises the following steps:
firstly, a first preset time t is set0Setting the value to be larger, and then separating the compressors of the two refrigerant circulation systems for a first preset time t0Starting operation (one refrigerant circulating system operates firstly), observing frosting conditions of air heat exchangers of two refrigerant circulating systems when the refrigerant circulating system operating firstly meets defrosting entrance conditions, and if the air side heat exchanger of the refrigerant circulating system operating later frosts less and does not need defrosting, setting the first preset time t0Is reduced, the above experiment is repeated until the first preset time t is obtained0An approximate range of values of;
step two, a first preset time t is set firstly0Separating the two refrigerant circulation systems (system A and system B) for a first preset time t0Starting, wherein the system A is started firstly, and then recording the evaporation temperature T of the system A after the two refrigerant circulating systems operate stably under the working conditionA0Evaporation temperature T of System BB0After the system A enters the defrosting process, recording the evaporating temperature T before the system A enters the defrosting processA1And the evaporation temperature T of the system B at the corresponding timeB1Calculating the evaporation temperature attenuation value delta T of the system AA＝TA1-TA0Evaporation temperature decay value Δ T of System BB＝TB1-TB0Comparing the two attenuation values, and if the difference is larger, properly reducing the preset time t0By trial and error, to obtain a first predetermined time t0An approximate range of values of;
step three, obtaining the first preset time t respectively from the step one and the step two0Is fitted to the approximate range of values of (a),finally determining the first preset time t0The value of (a).
Preferably, the first defrost entry condition (which is an existing defrost entry condition) is:
condition a, ambient temperature T of the environment in which the air heat exchanger of the refrigerant cycle system is locatedairNot more than first preset environmental temperature T0airAnd the first preset environmental temperature T0 is less than or equal to 5 DEG CairNot more than 15 ℃, and a first preset environmental temperature T0airPreferably 10 ℃; under the condition B, the defrosting accumulated running time of the refrigerant circulating system is more than or equal to a defrosting period T, and the defrosting period T is preferably 30 min; condition C, ambient temperature TairTemperature T of fin of air heat exchangerfIs less than a fourth preset temperature T3Fourth predetermined temperature T3Is greater than 0; the condition D is that the number of the refrigerant circulating systems in the defrosting process is less than the number N of the allowable defrosting systems of the air source heat pump unit, N is more than 0 and less than or equal to the number of the refrigerant circulating systems of the air source heat pump unit, N is an integer, and the number N of the allowable defrosting systems is preferably half of the number of the refrigerant circulating systems of the air source heat pump unit; condition E, Module Water out temperature TWONot less than the preset module water outlet temperature T0WOAnd the preset module water outlet temperature T0 is less than or equal to 5 DEG CWOThe temperature of the outlet water of the module is preset to be less than or equal to 15 ℃, and the temperature T0 of the outlet water of the module is presetWOPreferably 10 ℃, and the module is an air source heat pump unit. When any refrigerant circulating system in the air source heat pump unit meets the defrosting entering condition (namely, the conditions A-E are met at the same time), the refrigerant circulating system can enter the defrosting process.
Preferably, the second defrost entry condition (the defrost entry condition preferred by the present invention) is:
condition a, ambient temperature T of the environment in which the air heat exchanger of the refrigerant cycle system is locatedairNot more than first preset environmental temperature T0airAnd the first preset environmental temperature T0 is less than or equal to 5 DEG CairNot more than 15 ℃, and a first preset environmental temperature T0airPreferably 10 ℃;
under the condition B, the defrosting accumulated running time of the refrigerant circulating system is more than or equal to a defrosting period T, and the defrosting period T is preferably 30 min;
condition C, at ambient temperature Tair< second preset ambient temperature T1air-10 ℃ < second preset ambient temperature T1air< 0, a second preset ambient temperature T1airPreferably-4 ℃ and an evaporation temperature Te< K1 ambient temperature Tair-C0, and duration tc0Wherein 0.5. ltoreq.K 1. ltoreq.0.9, preferably 0.7 for K1, 10 < C0 < 20, preferably 13 for C0, tc0＞0s，tc0Preferably 120 s; or when the ambient temperature TairNot less than second preset environmental temperature T1airA second preset ambient temperature T1 of not less than 10 DEG CairNot more than 0 ℃, and a second preset environmental temperature T1airPreferably-4 ℃ and an evaporation temperature Te< K2 ambient temperature Tair-C1, and duration tc1，tc1＞0s，tc1Preferably 120s, wherein 0.6. ltoreq. K2. ltoreq.1.2, K2 is preferably 0.8, 9 < C1 < 19, C1 is preferably 12;
the condition D is that the number of the refrigerant circulating systems in the defrosting process is less than the number N of the allowable defrosting systems of the air source heat pump unit, N is more than 0 and less than or equal to the number of the refrigerant circulating systems of the air source heat pump unit, N is an integer, and the number N of the allowable defrosting systems is preferably half of the number of the refrigerant circulating systems of the air source heat pump unit;
condition E, Module Water out temperature TWONot less than the preset module water outlet temperature T0WOAnd the preset module water outlet temperature T0 is less than or equal to 5 DEG CWOThe temperature of the outlet water of the module is preset to be less than or equal to 15 ℃, and the temperature T0 of the outlet water of the module is presetWOPreferably 10 ℃, and the module is an air source heat pump unit. When any refrigerant circulating system in the air source heat pump unit meets the defrosting entering condition (namely, the conditions A-E are met at the same time), the refrigerant circulating system can enter the defrosting process.
The first defrosting entry condition is an existing defrosting entry condition, and the second defrosting entry condition is a defrosting entry condition preferentially adopted by the defrosting method of the present invention, and compared with the first defrosting entry condition, the opportunity for the refrigerant circulation system to enter the defrosting process can be more accurate, and the specific reasons are as follows:
when the air-side heat exchanger operates as an evaporator, the temperature of the refrigerant inside the heat exchange tubes is referred to as the evaporation temperature, the temperature of the air outside the heat exchange tubes is referred to as the ambient temperature, and the difference therebetween can be preliminarily considered as a heat transfer temperature difference (i.e., ambient temperature — evaporation temperature), which is related to the design of the heat exchanger and the ambient temperature when the heat exchanger operates, that is, even when the design of one heat exchanger has been determined, the heat transfer temperature difference changes with the change in the ambient temperature, for example:
the environment temperature is 7 ℃, the evaporation temperature is-4 ℃, and the heat transfer temperature difference is 11 ℃;
the environment temperature is-12 ℃, the evaporation temperature is-19 ℃, and the heat transfer temperature difference is 7 ℃;
thus, there is a calculated relationship between the evaporating temperature and the ambient temperature, rather than a constant difference. The general rule is as follows: the lower the ambient temperature, the lower the heat transfer differential of the air side heat exchanger.
Of course, even if the ambient temperature is the same, the heat transfer temperature difference may also be different, mainly because the influence of frosting on the surface of the air side heat exchanger will result in the heat exchanger performance becoming poor, and the evaporation temperature will drop, making the heat transfer temperature difference become large, for example, after frosting on the surface of the air side heat exchanger to a certain extent:
the environment temperature is 7 ℃, the evaporation temperature is-6 ℃, and the heat transfer temperature difference is 13 ℃;
the environment temperature is-12 ℃, the evaporation temperature is-21 ℃, and the heat transfer temperature difference is 9 ℃;
thus, after the heat exchanger has frosted, there is also a relationship between the evaporating temperature and the ambient temperature, rather than a constant difference.
Therefore, when the ambient temperature of the environment where the air side heat exchanger is located is fixed, if the heat transfer temperature difference is gradually increased, it indicates that the surface of the heat exchanger is frosted gradually, that is, the frosting amount and thickness of the surface of the heat exchanger can be judged according to the heat transfer temperature difference.
The main reasons why the first defrost entry condition produces an error (error, which means that when defrosting is performed according to the logic of the first defrost entry condition, the actual frosting on the surface of the heat exchanger may be "no defrosting needed" or "frosting is severe and needs to be defrosted at an earlier time") are as follows:
fin temperature instead of evaporation temperature: the temperature of the fins is measured by the temperature of the refrigerant at the inlet end of the heat exchanger, and is not the true evaporation temperature;
when the frosting degree is consistent, if the environmental temperature is different, the heat transfer temperature difference is also different, and in the condition C of the first defrosting entering condition, the environmental temperature T isairTemperature T of fin of air heat exchangerfIs less than a fourth preset temperature T3Fourth predetermined temperature T3Is greater than 0 and is a fixed value and does not change along with the change of the ambient temperature.
The second defrosting entry condition (i.e. the condition preferentially adopted by the defrosting method of the present invention) improves the accuracy of defrosting (i.e. when defrosting is performed according to the logic of the second defrosting entry condition, the real frosting condition of the heat exchanger surface is near the "defrosting needed" state), and the specific reasons are as follows:
the formula of the curve of the evaporation temperature and the ambient temperature is obtained by the following steps: evaporation temperature TeAmbient temperature T ═ K-airC, the curve formula is more scientific and accurate;
step one, an air source heat pump unit operates to heat until the surface of an air side heat exchanger is frosted and gradually thickened until the thickness of a frost layer reaches the thickness which needs to be defrosted (whether defrosting needs to be carried out or not can be determined by directly observing the thickness and the area ratio of the frost layer through naked eyes and the data such as the heating capacity and the attenuation percentage of the heating efficiency of the air source heat pump unit tested in a laboratory), and the evaporation temperature of the air source heat pump unit (namely the evaporation temperature of the air source heat pump unit at the moment which needs to be defrosted) is recorded;
and step two, performing the operation of the step one under a plurality of different environmental temperatures to finally obtain the curve formula.
In condition C of the second defrost entry condition, the evaporation temperature T is introducedeAmbient temperature Tair-C, i.e. the accuracy of the defrost of the second defrost entry condition is greatly improved.
Specifically, as shown in fig. 1-4, the air source heat pump unit includes 2 refrigerant circulation systemsThe system comprises a group of refrigerant circulating systems and a group of refrigerant circulating systems, wherein each group of refrigerant circulating systems comprises a compressor No. 1, each group of refrigerant circulating system is a first system, each group of refrigerant circulating system comprises a compressor No. 2, each group of refrigerant circulating system is a second system, an air side heat exchanger connected with the compressor No. 1 and an air side heat exchanger connected with the compressor No. 2 share a fan, and air circulation channels of the fans are communicated. As shown in fig. 1 to 4 in combination with fig. 7, when the first system meets the defrosting entry condition, it is determined that the defrosting accumulated running time difference t between the first system and the second system is equal to or greater than the defrosting accumulated running time difference tDAnd a first preset time t0If defrosting accumulates the running time difference tDNot more than first preset time t0If the defrosting operation time difference t is less than the preset defrosting operation time, the fan is turned off, the first system and the second system enter the defrosting process at the same time, and if the defrosting operation time difference t is less than the preset defrosting operation time difference t, the defrosting operation time difference is judged to be the preset defrosting operation time differenceDIs greater than a first preset time t0If the defrosting process is finished, the first system and the second system are automatically started. Furthermore, the first system meets defrosting entry conditions, the second system does not meet defrosting entry conditions, and the defrosting accumulated running time difference t of the first system and the second systemDNot more than first preset time t0Then the current evaporating temperature T of the second system is calculatedeIf the front evaporating temperature T of the second systemeAnd (3) the fan is closed, and the whole air source heat pump unit (namely the first system and the second system) enters a defrosting process: when the defrosting entry condition is not satisfied, the ambient temperature T of the environment in which the air-side heat exchanger of the refrigerant cycle system is locatedairAt < -4 ℃ and Te＜(K1*Tair-A1) + B1, or when the ambient temperature T isairNot less than-4 ℃ and Te＜(K2*Tair-a2) + B2, wherein K1-0.7, a 1-13, B1-1, K2-0.8, a 2-12, B2-1. If the current evaporating temperature T of the second systemeAnd if the condition is not met, the fan is closed, only the first system enters the defrosting process, the second system is stopped for waiting, and after the first system finishes the defrosting process, the first system and the second system are automatically started.
Preferably, as shown in fig. 9, in step three, if defrosting, the operation time t is accumulatedDNot more than first preset time t0Then, the evaporating temperature difference DeltaT of the set of the refrigerant cycle system which does not satisfy the defrosting entry condition is calculatedeDifference in evaporating temperature Δ TeIs the current evaporating temperature T of the refrigerant cycle systemeDifference value of evaporating temperature required by said refrigerant circulating system to make defrosting process, if the evaporating temperature difference is delta TeNot more than first preset temperature T0First predetermined temperature T0If the temperature is more than 0, the whole air source heat pump unit enters a defrosting process; if the difference of evaporation temperature is Delta TeGreater than a first predetermined temperature T0Only the refrigerant cycle system satisfying the defrost entry condition enters the defrost process.
Specifically, as shown in fig. 1 to 4 in combination with fig. 9, the first system satisfies the defrosting entry condition, the second system does not satisfy the defrosting entry condition, and the defrosting integrated operation time t of the first system and the second systemDNot more than first preset time t0Then the evaporating temperature difference DeltaT of the second system is calculatedeIf the difference in evaporation temperature is Δ TeNot more than first preset temperature T0Then the fan is closed, the whole air source heat pump unit (the first system and the second system) enters the defrosting process, and if the evaporation temperature difference delta T is larger than the preset temperature, the air source heat pump unit is started to defrosteGreater than a first predetermined temperature T0And then the fan is closed, only the first system enters the defrosting process, the second system is stopped for waiting, and after the first system finishes the defrosting process, the first system and the second system are automatically started.
Fig. 8 shows a second embodiment of the defrosting method of the air source heat pump unit according to the present invention.
The present embodiment differs from the first embodiment in that: in this embodiment, the air source heat pump unit includes at least two refrigerant circulation systems, and ventilation systems of the respective refrigerant circulation systems are independent of each other (i.e., as shown in fig. 5 and 6, fans used in air-side heat exchangers of the respective refrigerant circulation systems are different, and air flow channels of the fans are independent of each other). The difference between the defrosting method of the air source heat pump unit in the embodiment and the first embodiment is that: if the whole air source heat pump unit (namely all the refrigerant circulating systems) enters the defrosting process, all the fans are closed, and all the refrigerant circulating systems enter the defrosting process; if only part of the refrigerant circulation system in the air source heat pump unit enters the defrosting process, the fan of the part of the refrigerant circulation system is closed and enters the defrosting process, and the other part of the refrigerant circulation system normally works (namely, the heating mode is kept).
Specifically, as shown in fig. 5, 6, 8, and 10, the air source heat pump unit includes two sets of refrigerant circulation systems, which are a first system and a second system, respectively, where the first system includes a blower 1 and a compressor 1, the second system includes a blower 2 and a compressor 2, when the first system and the second system both enter a defrosting process, the blower 1 and the blower 2 are both turned off, and the compressor 1 and the compressor 2 both enter a refrigeration mode; if only the second system enters the defrosting process, the fan 1 is started, the compressor 1 keeps in the heating mode, the fan 2 is closed, and the compressor 2 enters the refrigerating mode.
The invention discloses a defrosting method of the air source heat pump unit and also discloses a condition for the refrigerant circulating system to exit the defrosting process.
The air source heat pump unit comprises at least two groups of refrigerant circulating systems and a control system connected with the refrigerant circulating systems, and the control system judges that the refrigerant circulating system in the defrosting process meets any one of the following conditions, and controls the refrigerant circulating system to quit the defrosting process: condition a, fin temperature T of air-side heat exchanger of the refrigerant cycle systemfNot less than the preset defrosting exit fin temperature Tf0The preset defrosting exit fin temperature T is less than or equal to 20 DEG Cf0Not more than 45 ℃; condition b, defrost operating time T of the refrigerant cycle systemCNot less than the maximum time T of the defrosting processCMAXAnd the maximum time T of the defrosting process is less than or equal to 3minCMAXLess than or equal to 10 min; condition c, the refrigerant cycle system high-pressure switch is off; condition d, Module Water out temperature TWODefrosting exit water temperature T is not more thanWO0Defrosting exit water temperature T is less than or equal to 5 DEG CW0Less than or equal to 25 ℃. Further, the preset defrosting exit fin temperature Tf0Is 30 ℃; maximum time T of defrosting processCMAXIs 5 min; in the condition c, after the high-voltage switch of the refrigerant cycle system is turned offThe compressor of the refrigerant circulating system is immediately stopped and the defrosting process is stopped; the defrosting exit water temperature TW0Is 10 ℃.
Preferably, the control system may correct the next defrost cycle of the refrigerant cycle according to a condition that the refrigerant cycle finishes the defrost process: if the refrigerant circulation system in the defrosting process exits the defrosting process because the condition a is met, the control system corrects the next defrosting cycle increasing time T of the refrigerant circulation systemp1，5min≤Tp1Less than or equal to 20 min; if the refrigerant cycle system in the defrosting process exits the defrosting process because the condition b is satisfied, the control system corrects the next defrosting cycle reduction time T of the refrigerant cycle systemp2，5min≤Tp2Less than or equal to 20 min; the next defrosting period of the refrigerant circulating system which is modified must be more than or equal to the minimum allowable defrosting period TCMIN0 < minimum allowable defrost cycle TCMINLess than or equal to 60 min. Further, the minimum allowable defrost period TCMINIt is 30 min. Specifically, if the refrigerant circulation system exits the defrosting process due to the fact that the condition a is met, the defrosting of the air heat exchanger is smooth at this time, and defrosting is thorough, and the condition that the air heat exchanger frosts less or the operating working condition (climate condition) of the air heat exchanger is good before the defrosting process at this time is also described, so that the time of the next defrosting period can be properly prolonged by at most 20 minutes; if the refrigerant cycle system exits the defrosting process by satisfying the condition b, it means that the fin temperature T is highfIf the conditions are not met and the defrosting process is finished, the fact that the air heat exchanger is likely to be unclean and incomplete in defrosting is indicated, and the fact that the air heat exchanger is thick in frosting during the defrosting process is also indicated, so that the time of the next defrosting period can be properly shortened, the next defrosting process can come in advance, and the phenomenon that the air heat exchanger (such as fins) is thicker in frosting is avoided.
It should be noted that, the defrosting cycle refers to a time interval between two adjacent 2 defrosting processes, and the duration of the defrosting cycle should be prolonged as much as possible to prevent the number of times of defrosting from being too large, so that the defrosting time accounts for too high proportion of the heating operation time of the whole air source heat pump unit.
It should be noted that, when the refrigerant circulation system is in the defrosting process, the refrigerant circulation system operates in the cooling mode and the fan is turned off.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (11)
1. The defrosting method of the air source heat pump unit is characterized in that the air source heat pump unit comprises at least two sets of refrigerant circulating systems, each set of refrigerant circulating system comprises an air side heat exchanger, and the air side heat exchanger is a fin heat exchanger; the defrosting method comprises the following steps:
step one, determining a refrigerant circulating system meeting defrosting entry conditions;
step two, calculating the difference value t between the defrosting accumulated running time of a certain set of refrigerant circulating system which does not meet the defrosting entering condition and the defrosting accumulated running time of the refrigerant circulating system which meets the defrosting entering conditionD；
Step three, comparing the defrosting accumulated running time difference tDAnd a first preset time t0Wherein t is0＞0：
If the defrosting operation time difference t is accumulatedDNot more than first preset time t0If the defrosting condition is satisfied, the set of refrigerant circulating system which does not satisfy the defrosting entering condition and the set of refrigerant circulating system which satisfies the defrosting entering condition both enter the defrosting process;
if the defrosting operation time difference t is accumulatedDIs greater than a first preset time t0If so, the refrigerant circulating system meeting the defrosting entry condition enters the defrosting process, and the set of refrigerant circulating system not meeting the defrosting entry condition stops to wait or continues to work normally;
and step four, repeating the step two and the step three, and judging whether all the refrigerant circulating systems which do not meet the defrosting entering condition can enter the defrosting process.
2. The defrosting method of an air source heat pump unit according to claim 1, characterized in that: less than or equal to 5min and a first preset time t0≤30min。
3. The defrosting method of an air source heat pump unit according to claim 1, characterized in that: in the third step, if defrosting accumulates the running time difference tDNot more than first preset time t0Then, the evaporating temperature difference DeltaT of the set of the refrigerant cycle system which does not satisfy the defrosting entry condition is calculatedeDifference in evaporating temperature Δ TeIs the difference value between the current evaporation temperature of the set of the refrigerant circulating system and the evaporation temperature required by the set of the refrigerant circulating system to enter the defrosting process, if the difference value of the evaporation temperatures is delta TeNot more than first preset temperature T0First predetermined temperature T0If the temperature is more than 0, the refrigerant circulating system enters a defrosting process; if the difference of evaporation temperature is Delta TeGreater than a first predetermined temperature T0If the defrosting condition is satisfied, the refrigerant circulation system which does not satisfy the defrosting condition is stopped to wait or normally works.
4. The defrosting method of an air source heat pump unit according to claim 1 or 3, characterized in that: in the third step, if defrosting accumulates the running time difference tDNot more than first preset time t0Then the current evaporating temperature T of the set of refrigerant cycle system which does not satisfy the defrosting entry condition is calculatedeAnd the current evaporation temperature TeThe set of the refrigerant circulating system enters a defrosting process when the following conditions are met: when the ambient temperature T of the environment where the air side heat exchanger of the set of refrigerant cycle system does not meet the defrosting entry conditionair< second predetermined temperature T1 and Te＜(K1*Tair-A1) + B1, or when the ambient temperature T isairNot less than a second predetermined temperature T1 and Te＜(K2*Tair-a2) + B2; it is composed ofWherein T1 is more than-8 ℃ and less than 0 ℃, K1 is more than or equal to 0.5 and less than or equal to 0.9, A1 is more than 10 and less than 20, B1 is more than 0 and less than 2, K2 is more than or equal to 0.6 and less than or equal to 1.2, A2 is more than 11 and less than 19, and B2 is more than 0 and less than 2;
if the current evaporation temperature T of the set of refrigerant circulating system does not meet the defrosting entry conditioneIf the condition is not met, the refrigerant circulating system meeting the defrosting entry condition normally works or stops to wait when the refrigerant circulating system meeting the defrosting entry condition enters the defrosting process.
5. The defrosting method of an air source heat pump unit according to claim 3, characterized in that: the second preset temperature T1 is-4 ℃, K1 is 0.7, a1 is 13, B1 is 1, K2 is 0.8, a2 is 12, and B2 is 1.
6. The defrosting method of an air source heat pump unit according to claim 1, characterized in that: the calculation method of the defrosting cumulative operation time is as follows,
wherein, the starting timing condition is as follows: after the refrigerant circulating system is heated and started for the first time or after the defrosting process is finished and the heating and starting are recovered, the refrigerant circulating system is started from the evaporating temperature TeTiming is started when the temperature is less than the third preset temperature T2, wherein the temperature is less than minus 7 ℃ and less than the third preset temperature T2 and less than 3 ℃;
if during the time course, the evaporation temperature TeThe time is cleared when the temperature is equal to or more than the third preset temperature T2 and the duration is more than T1, wherein T1 is equal to or more than 30s, and the temperature is at the evaporation temperature TeRestarting timing at the moment of being less than the third preset temperature T2;
if the refrigerant circulating system is stopped in the timing process, the timing is stopped and the zero clearing is not carried out, the refrigerant circulating system is started again, the running time is more than or equal to the time T3, the time T3 is more than 0, and if the evaporation temperature T is higher than or equal to the evaporation temperature TeThe time is reset when the temperature is equal to or more than the third preset temperature T2 and the duration time is more than T1, and the temperature is at the evaporating temperature TeRestarting timing at the moment of being less than the third preset temperature T2; if the refrigerant circulating system is stopped in the timing process, the timing is stopped and is not cleared, the refrigerant circulating system is started again, the running time is not less than T3, and if the evaporation temperature T is lower than Te< the third preset temperature T2,the time is accumulated and only the evaporation temperature T is accumulatede< time of the third preset temperature T2.
7. The defrosting method of an air source heat pump unit according to claim 1, characterized in that: the defrosting entry conditions are as follows: condition A, ambient temperature TairNot more than first preset environmental temperature T0airAnd the first preset environmental temperature T0 is less than or equal to 5 DEG CairLess than or equal to 15 ℃; the condition B is that the accumulated defrosting operation time is more than or equal to the defrosting period T; condition C, ambient temperature TairTemperature T of finfIs less than a fourth preset temperature T3Fourth predetermined temperature T3Is greater than 0; the condition D is that the number of the refrigerant circulating systems in the defrosting process is less than the number N of the allowable defrosting systems of the air source heat pump unit, N is more than 0 and less than or equal to the number of the refrigerant circulating systems in the air source heat pump unit, and N is an integer; condition E, Module Water out temperature TWONot less than the preset module water outlet temperature T0WOAnd the preset module water outlet temperature T0 is less than or equal to 5 DEG CWOThe temperature is less than or equal to 15 ℃, and the module is an air source heat pump unit.
8. The defrosting method of an air source heat pump unit according to claim 1, characterized in that:
the defrosting entry conditions are as follows:
condition A, ambient temperature TairNot more than first preset environmental temperature T0airAnd the first preset environmental temperature T0 is less than or equal to 5 DEG Cair≤15℃；
The condition B is that the accumulated defrosting operation time is more than or equal to the defrosting period T;
condition C, at ambient temperature Tair< second preset ambient temperature T1airA second preset ambient temperature T1 of not less than 10 DEG CairNot more than 0, evaporation temperature Te< K1 ambient temperature Tair-C0, and duration tc0Wherein K1 is more than or equal to 0.5 and less than or equal to 0.9, CO is more than 10 and less than 20, tc0Is more than 0 s; or when the ambient temperature TairNot less than second preset environmental temperature T1airA second preset ambient temperature T1 of not less than 10 DEG CairNot more than 0, evaporation temperature Te< K2 ambient temperature Tair-C1, and duration tc1Wherein K2 is more than or equal to 0.6 and less than or equal to 1.2, C1 is more than 9 and less than 19, and tc1＞0s；
The condition D is that the number of the refrigerant circulating systems in the defrosting process is less than the number N of the allowable defrosting systems of the air source heat pump unit, N is more than 0 and less than or equal to the number of the refrigerant circulating systems of the air source heat pump unit, and N is an integer;
condition E, the module outlet water temperature is more than or equal to the preset module outlet water temperature T0WOAnd the preset module water outlet temperature T0 is less than or equal to 5 DEG CWOThe temperature is less than or equal to 15 ℃, and the module is an air source heat pump unit.
9. The defrosting method of an air source heat pump unit according to claim 7, characterized in that: the defrosting period T is 30min, and the first preset environment temperature T0airThe temperature is 10 ℃, N is half of the number of refrigerant circulating systems in the air source heat pump unit, and the outlet water temperature T0 of the module is presetWOIs 10 ℃.
10. The defrosting method of an air source heat pump unit according to claim 8, characterized in that: in condition a, the first preset ambient temperature T0airIs 10 ℃; in the condition B, the defrosting period T is 30 min; in condition C, the second preset ambient temperature T1airAt a temperature of-4 ℃ tc0＝120s，tc1120s, 0.7 for K1, 13 for C0, 12 for C1, 0.8 for K2; in the condition D, the number N of the allowable defrosting systems is half of the number of the refrigerant circulating systems in the air source heat pump unit; in condition E, the module outlet water temperature T0 is presetWOIs 10 ℃.
11. The defrosting method of an air source heat pump unit according to claim 1, characterized in that: comprising M0Refrigerant circulating system, M0Is an integer greater than 2; if the air source heat pump unit has M in the same moment1The refrigerant circulating system meets the defrosting entry condition, M12 or more and less than the total number of the refrigerant circulating systems; in step two, a certain set of refrigerant circulating system which does not meet the defrosting entry condition and a set of refrigerant circulating system which meets the defrosting entry condition and is defrosted are calculatedDefrosting accumulated operation time difference t of refrigerant circulation system with shortest operation timeD。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910815218.5A CN110715481B (en) | 2019-08-30 | 2019-08-30 | Defrosting method of air source heat pump unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910815218.5A CN110715481B (en) | 2019-08-30 | 2019-08-30 | Defrosting method of air source heat pump unit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110715481A true CN110715481A (en) | 2020-01-21 |
| CN110715481B CN110715481B (en) | 2023-08-08 |
Family
ID=69209585
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910815218.5A Active CN110715481B (en) | 2019-08-30 | 2019-08-30 | Defrosting method of air source heat pump unit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110715481B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112283992A (en) * | 2020-10-29 | 2021-01-29 | 广东海悟科技有限公司 | Double-system heat pump defrosting method, computer storage medium and double-system heat pump unit |
| CN112539520A (en) * | 2020-12-17 | 2021-03-23 | 珠海格力电器股份有限公司 | Defrosting control method and device and multi-split air conditioner |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20000038964A (en) * | 1998-12-10 | 2000-07-05 | 윤종용 | Method for controlling defrosting operation of air conditioner |
| JP2005090784A (en) * | 2003-09-12 | 2005-04-07 | Matsushita Electric Ind Co Ltd | Defrost adjusting device and controlling method, and heat pump type water heater |
| CN104180570A (en) * | 2014-07-30 | 2014-12-03 | 珠海格力电器股份有限公司 | Defrosting control method and system for heat pump air conditioning unit |
| CN104913452A (en) * | 2015-06-03 | 2015-09-16 | 广东美的制冷设备有限公司 | Air conditioner and defrosting control method for same |
| CN107388626A (en) * | 2017-08-22 | 2017-11-24 | 广东美的暖通设备有限公司 | Multisystem heat pump components, defrosting control method and storage medium |
| CN109059374A (en) * | 2018-06-14 | 2018-12-21 | 浙江正理生能科技有限公司 | A kind of air source heat pump defrosting control method |
-
2019
- 2019-08-30 CN CN201910815218.5A patent/CN110715481B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20000038964A (en) * | 1998-12-10 | 2000-07-05 | 윤종용 | Method for controlling defrosting operation of air conditioner |
| JP2005090784A (en) * | 2003-09-12 | 2005-04-07 | Matsushita Electric Ind Co Ltd | Defrost adjusting device and controlling method, and heat pump type water heater |
| CN104180570A (en) * | 2014-07-30 | 2014-12-03 | 珠海格力电器股份有限公司 | Defrosting control method and system for heat pump air conditioning unit |
| CN104913452A (en) * | 2015-06-03 | 2015-09-16 | 广东美的制冷设备有限公司 | Air conditioner and defrosting control method for same |
| CN107388626A (en) * | 2017-08-22 | 2017-11-24 | 广东美的暖通设备有限公司 | Multisystem heat pump components, defrosting control method and storage medium |
| CN109059374A (en) * | 2018-06-14 | 2018-12-21 | 浙江正理生能科技有限公司 | A kind of air source heat pump defrosting control method |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112283992A (en) * | 2020-10-29 | 2021-01-29 | 广东海悟科技有限公司 | Double-system heat pump defrosting method, computer storage medium and double-system heat pump unit |
| CN112539520A (en) * | 2020-12-17 | 2021-03-23 | 珠海格力电器股份有限公司 | Defrosting control method and device and multi-split air conditioner |
| CN112539520B (en) * | 2020-12-17 | 2021-10-22 | 珠海格力电器股份有限公司 | Defrosting control method and device and multi-split air conditioner |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110715481B (en) | 2023-08-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2019149163A1 (en) | Vrv oil return control method and system | |
| CN103363614B (en) | Air-cooled cold and hot water air conditioning unit and defrosting control method and device thereof | |
| CN103363600B (en) | Heat pump type air conditioner | |
| US20050284174A1 (en) | Cooling cycle apparatus and method of operating the same | |
| WO2010038518A1 (en) | Air conditioner | |
| CN110094831B (en) | Multi-split air conditioner and defrosting control method thereof | |
| CN111140976A (en) | Fresh air conditioning system and control method thereof | |
| CN110715481A (en) | Defrosting method of air source heat pump unit | |
| CN104903656A (en) | Air conditioner | |
| CN110470011A (en) | Control method and device, air-conditioning for air-conditioner defrosting | |
| CN103363601A (en) | Heat pump type air conditioner | |
| WO2020019849A1 (en) | Air conditioner and outdoor unit defrosting control method thereof | |
| KR101491909B1 (en) | Out door unit capable of defrosting and heat pump system including the out door unit | |
| CN110542175A (en) | air conditioner defrosting method | |
| CN110715482A (en) | Defrosting method of air source heat pump unit | |
| WO2019171463A1 (en) | Air conditioning device | |
| CN212179138U (en) | Fresh air conditioning system | |
| CN110608510B (en) | Air conditioner, outdoor unit, defrosting device, defrosting control method and defrosting control system | |
| CN110553328A (en) | Air conditioning system and control method thereof | |
| CN104848578B (en) | The control method of air conditioner and air conditioner | |
| CN110271390A (en) | Air conditioner for vehicles | |
| CN113370752B (en) | Whole car thermal management system with defrosting function | |
| US20210254880A1 (en) | Air conditioner and method for controlling an air conditioner | |
| CN210624788U (en) | Air conditioning system | |
| CN114440401A (en) | Air source heat pump unit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |