CN107860146A - A kind of control method of air source heat pump system - Google Patents
A kind of control method of air source heat pump system Download PDFInfo
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- CN107860146A CN107860146A CN201710976202.3A CN201710976202A CN107860146A CN 107860146 A CN107860146 A CN 107860146A CN 201710976202 A CN201710976202 A CN 201710976202A CN 107860146 A CN107860146 A CN 107860146A
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- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000000748 compression moulding Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- 238000009790 rate-determining step (RDS) Methods 0.000 abstract 4
- 230000002262 irrigation Effects 0.000 abstract 1
- 238000003973 irrigation Methods 0.000 abstract 1
- 238000010977 unit operation Methods 0.000 abstract 1
- 238000010438 heat treatment Methods 0.000 description 19
- 230000008569 process Effects 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 230000009977 dual effect Effects 0.000 description 7
- 239000007788 liquid Substances 0.000 description 6
- 238000006073 displacement reaction Methods 0.000 description 5
- 230000001502 supplementing effect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000005057 refrigeration Methods 0.000 description 4
- 239000006096 absorbing agent Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- WOAFDHWYKSOANX-UHFFFAOYSA-N diisopropyl methylphosphonate Chemical compound CC(C)OP(C)(=O)OC(C)C WOAFDHWYKSOANX-UHFFFAOYSA-N 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
- F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
-
- 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
- F25B49/022—Compressor control arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/02—Compressor control
- F25B2600/022—Compressor control for multi-stage operation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
- F25B2700/2106—Temperatures of fresh outdoor air
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention discloses a kind of control method of air source heat pump system, aim to provide a kind of control logic and control method of the frequency conversion air-cooled heat pump circulating system design changeable based on direct-connected twin-stage and double parallel, the present invention is the Air-Cooled Heat Pump Unit based on frequency-changeable compressor, its drip irrigation device is, including the rate-determining steps by unit operation pattern switching to double parallel operational mode；Double-click the rate-determining steps that paralleling model is switched to single compressor operational mode；Second compressor mode is switched to the rate-determining steps of direct-connected bipolar mode of operation；Direct-connected bipolar mode of operation is switched to the rate-determining steps of the second compressor operating pattern.
Description
Technical Field
The invention relates to the field of refrigeration and air-conditioning system control, in particular to a control method of an air-cooled screw heat pump system.
Background
The air-cooled heat pump unit is a circulating system formed by a compressor, a heat exchanger, a restrictor, a heat absorber, a compressor and the like. The refrigerant circulates in the system under the action of the compressor. The compressor completes the gas-state pressure-raising and temperature-raising process (the temperature is up to 100 ℃), the gas-state pressure-raising and temperature-raising process enters the heat exchanger, the gas-state pressure-raising and temperature-raising process exchanges heat with wind, the gas-state pressure-raising and temperature-raising process is cooled and converted into liquid state, when the gas-state pressure-raising and temperature-raising process runs to the heat absorber, the liquid state absorbs heat quickly, evaporates and is converted into gas state again, and the temperature is reduced to minus 20 ℃ -30 ℃, and. The continuous circulation of the refrigerant realizes the process that the low-temperature heat in the air is converted into the high-temperature heat and the cold water is heated.
Currently, as shown in fig. 1, the main components include: 2 screw compressors, 1 oil separator, 2 four-way reversing valves, 1 evaporator, 1 flash evaporation type economizer, 1 platen heat exchanger, 1 main expansion valve, 1 first expansion valve and 1 differential pressure valve. In the prior art, two screw compressors are arranged in series for an air-cooled heat pump system, the exhaust of a first compressor is directly connected to the suction of a second compressor, an oil separator at the exhaust outlet of the second compressor is shared, and the oil separator realizes oil supply and lubrication of the second compressor and the first compressor. And meanwhile, the condenser, the evaporator, the expansion valve, the four-way valve, the valve and the like are shared. The design requirements of the high pressure head of the air-cooled heat pump unit for high-temperature refrigeration in summer and low-temperature heating in winter can be met.
However, the operation of the air-cooled screw heat pump system is generally single and complex.
Disclosure of Invention
The invention aims to provide a control method of an air-cooled screw heat pump system, which is a control method designed for a direct-connection two-stage and double-machine parallel switchable variable-frequency air-cooled heat pump circulating system and is simple in whole.
The technical purpose of the invention is realized by the following technical scheme:
a control method of an air-cooled screw heat pump system comprises the air-cooled screw heat pump system and comprises the following control steps of switching a single machine operation mode to a double machine parallel operation mode: d1, closing the low-pressure exhaust stop valve (14); d2, unloading the first compressor (101) or the second compressor (102) being operated to a load; d3, loading the second compressor (102) or the first compressor (101) in the standby state to a load, so that the two compressors run to the same load; d4, the oil return electromagnetic valve (212) is opened after delaying for 5 seconds, and the bypass electromagnetic valve (29) is opened after delaying for 5 seconds.
By adopting the technical scheme, the system can operate in the refrigerating working condition in summer and the heating working condition in winter. When the heat pump is operated under the heating working condition, a single-machine operation mode, a direct-connection double-stage operation mode and a double-machine parallel operation mode can be realized, and the 3 operation modes can be switched arbitrarily according to the load requirement, the operation efficiency and the operation reliability. The compressor adopted by the system must be a variable frequency screw compressor, a variable frequency scroll compressor, a variable frequency rotor compressor, a variable frequency centrifugal compressor and the like. But the operating speed must be adjustable by frequency conversion to achieve energy regulation. According to the operating parameters of the compressor, the method comprises the following steps: the exhaust saturation temperature or exhaust pressure, the suction saturation temperature or suction pressure, the compressor running frequency and the unit working condition parameters comprise: ambient temperature, hot water inlet temperature, or outlet water temperature. The switching time between the 3 operation modes can be determined according to the parameters and the calculation formula of the parameters, and the operation frequency of the two compressors can be determined after switching.
Further setting: the method comprises the following control steps of switching a double-click parallel mode to a single-compressor running mode: s1, selecting the compressor with longer running time in the first compressor (101) or the second compression molding machine (102) to stop; s2, closing the low-pressure exhaust stop valve (14); s3, loading the second compressor (102) or the first compressor (101) which is operated to a load; s4, the oil return electromagnetic valve (212) is closed, and the bypass electromagnetic valve (29) is closed.
Further setting: comprising the control step of switching the second compressor mode to the direct connection bipolar operation mode: p1, opening a low-pressure exhaust stop valve (14); p2, unloading the second compressor (102) being operated to a specified load; p3, loading the first compressor (101) in the standby state; p4, after the first compressor (101) is started, the oil return electromagnetic valve (212) is started after 5 seconds of delay, and the bypass electromagnetic valve (29) is kept closed.
Further setting: the method comprises the following control steps of switching a direct connection bipolar operation mode to a second compressor operation mode: a first compressor (101) shutdown comprising T1; t2, closing the low-pressure exhaust stop valve (14) after delaying for 2 seconds; t3, after the first compressor (101) is stopped, loading the second compressor (102) in the running state to a load; t4, the oil return solenoid valve (212) is closed, and the bypass solenoid valve (29) is closed.
By adopting the technical scheme, when the first compressor (101) is started and operates in the direct connection double-stage operation mode, the operation frequency before the first compressor (101) is started is determined (the total heating capacity of the first compressor (101) after starting in the direct connection double-stage operation mode and the heating capacity of the first compressor only in the second operation mode are ensured to be basically equal, and after the compressor is started, the load and the water temperature do not obviously fluctuate): when the system runs in a direct connection double-stage running mode after the first compressor (101) is started, the running frequency of the first compressor is determined according to the running frequency of the second compressor at the moment: the first compressor (101) will run to this frequency after start-up. Before the first compressor (101) is started and operates in a direct connection double-stage operation mode, the operation frequency of the second compressor (102) is determined (the total heating capacity of the first compressor (101) after starting in the direct connection double-stage operation mode and the heating capacity of the second compressor only in the direct connection double-stage operation mode are guaranteed to be basically equal, after the compressors are started, the load and the water temperature do not fluctuate obviously), and the first compressor (101) is unloaded to the frequency before starting. When the first compressor (101) is closed and the direct-connection two-stage operation mode is exited, the operation mode of the second compressor (102) is switched to, and after the first compressor (101) is closed, the operation frequency of the second compressor needs to be determined as follows (aiming at keeping the unit heating quantity before and after the first compressor is closed basically unchanged, so that the load and the water temperature can not obviously fluctuate.
Drawings
FIG. 1 is a schematic structural diagram of an air-cooled screw heat pump system;
FIG. 2 is a schematic diagram of the energy regulation control of the air-cooled screw heat pump system;
FIG. 3 is another schematic diagram of the energy regulation control of the air-cooled screw heat pump system;
FIG. 4 is a schematic view of the operation control mechanism of the various valves when the air-cooled screw heat pump system is switched between a single machine operation mode and a dual machine parallel operation mode;
FIG. 5 is a schematic view of the control of the operation of the various valves when the air-cooled screw heat pump system is switched between a stand-alone mode of operation and a direct-coupled dual-stage mode of operation;
fig. 6 is a schematic diagram of the entry and exit conditions for an air-cooled screw heat pump system to switch between a stand-alone mode of operation and a direct-coupled dual stage mode of operation.
In the figure, 1, a first compressor; 1001. a suction line A; 1002. an exhaust line A; 1003. an exhaust line B; 1004. an exhaust line C; 1005. a pipeline; 1006. a suction line B; 1007. an exhaust line D; 1011. a high-pressure stage compressor gas supplement pipeline; 1012. a low-pressure stage compressor gas supplementing pipeline; 114. a gas supplementing stop valve B; 115. a gas supplementing one-way valve B; 2. a second compressor; 29. an oil supply electromagnetic valve A; 210. an exhaust check valve; 212. an oil supply electromagnetic valve B; 214. a gas supplementing stop valve A; 215. a gas supplementing one-way valve A; 3. an oil separator; 5. an exhaust stop valve; 6. a first four-way reversing valve; 7. a second four-way reversing valve; 9. an evaporator; 12. an air intake bypass check valve; 13. an oil pump; 131. an oil pump check valve; 132. an oil cooler; 14. an oil supply line A; 141. an oil supply line B; 1411. an oil supply solenoid valve; 142. an oil supply line C; 1421. a differential pressure valve; 16. a first air side heat exchanger; 17. a second air side heat exchanger; 18. a liquid path drying filter; 19. a main liquid supply electronic expansion valve; 20. a first economic device; 21. a second economizer; 22. the evaporator is provided with a liquid supply expansion valve; 25. a liquid supply bypass electromagnetic valve; 26. an oil eductor; 27. a refrigeration check valve A; 28. a refrigeration check valve B; 29. an oil supply electromagnetic valve B; 30. a heating one-way valve A; 31. a heating one-way valve B; 32. an injection check valve; 33. an injection electromagnetic valve; 34. an exhaust check valve A; 35. and an exhaust check valve B.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Example 1: a control method of an air-cooled screw heat pump system comprises the following steps:
the key to the two-stage compression control is how to effectively control the intermediate pressure, i.e., reasonably match the load percentages controlling the high pressure stage and the first compressor, keeping the intermediate pressure stable.
In the initial stage of starting, either the first compressor 101 or the second compressor 102 must be started, and the second compressor 102 is generally set as a Lead advanced system, and the first compressor 101 is set as a Lag system; the Lead compressor is started preferentially when the compressor is started, and the Lag compressor is closed preferentially when the compressor is stopped. The energy control logic of the dual-machine parallel and dual-stage unit is shown in the lower graph 2. FIG. 3 illustrates the control of the operation of the various valves when switching between the single-machine mode of operation and the dual-machine parallel mode of operation; FIG. 4 illustrates the control of the actuation of the various valves when switching between the stand-alone mode of operation and the direct-coupled dual-stage mode of operation; FIG. 5 below illustrates entry and exit conditions for switching between a stand-alone mode of operation and a direct-coupled dual-stage mode of operation;
the working principle is as follows: as shown, switching from the second compressor operating mode only to the direct connection dual-stage operating mode (with the aim of confirming that the conditions are met can switch to the direct connection dual-stage operating mode): when the unit is operated in the heat pump working condition flow a, the flow b is performed when only the second compressor 102 is operated in the single machine operation mode, and the flow c with the loading requirement requires further improvement of the heating capacity of the unit. It is necessary to adjust the operation load HZ of the second compressor 102 according to the moment_only_HSExhaust saturation temperature T of the second compressor 102_sat_dsch_HSAnd suction saturation temperature T_sat_suct_HSTo determine whether the first compressor 101 needs to be turned on to operate in the direct-coupled dual-stage operation mode. If the following conditions are satisfied: (1) heating operation and ambient temperature TambThe temperature T of hot water outlet and less than or equal to 2 DEG ClhwtThe temperature is more than or equal to 45 ℃ and the flow f is carried out; (2) DT_act_HS＞DT_cmpd_HSAnd the process h; (3) HZ_act_HS＞150HZAnd flow h; (4) a countdown timer, namely a flow j, which can adjust the loading requirement and set for 2 minutes; within 2 minutes, if the conditions of (1) to (4) are not met, the timer is reset, and if the conditions of (1) to (3) are met for 2 minutes continuously, the timer is cleared; the condition for switching from the second compressor operation mode only to the direct connection two-stage operation mode, the first compressionThe machine (101) is enabled to start, i.e. the process 12.
DT_cmpd_HS＝0.469×HZ_act_HS-14.7
DT_act_Hs＝T_sat_dsch_Hs-T_sat_suct_HS
Wherein,
DT_cmpd_HS: conditions to be met by the direct connection two-stage operation mode; unit degree C;
Tsat_dsch_HS: the discharge saturation temperature in units of actual operation of the second compressor 102;
T_sat_suct_HS: the suction saturation temperature, in units, of the actual operation of the second compressor 102;
DT_act_HS: the difference in exhaust saturation temperature and suction saturation temperature, in units, of actual operation of the second compressor 102;
DZ_act_HS: the actual operating frequency of the second compressor 102, in HZ.
Switching from the second compressor operation mode to the dual parallel operation mode only (in order to confirm that the condition is satisfied, switching to the dual parallel operation mode is possible): if the following condition is not satisfied:
(1) heating operation is carried out, the environmental temperature is less than or equal to 7 ℃, the water outlet temperature is greater than or equal to 45 ℃, and the process 6 is carried out;
(2)DT_act_HS＞DT_cmpd_HSand flow f;
(3)HZ_act_HS＞150HZflow f, but with a load demand, switches from the second compressor only operating mode to two stages
Parallel operating mode, the energy regulation is controlled as shown in fig. 2.
When the first compressor 101 is started and operated in the direct connection two-stage operation mode, the operation frequency is determined before the first compressor 101 is started (ensuring the first compression)The total heating capacity of the machine 101 during direct-connection two-stage operation after starting and the heating capacity of the machine only during high-pressure stage operation are kept basically equal, and after the compressor is started, the load and the water temperature do not fluctuate obviously; when the system operates in the direct-connection two-stage operation mode after the first compressor 101 is started, the operation frequency HZ of the first compressor_cmpd_BSAccording to the operating frequency HZ of the second compressor at the moment_oniy_HSTo decide: the first compressor 101 will run to this frequency HZ after starting_cmpd_HSThe following steps of (1); i.e., scheme n.
HZ_cmpd_BS＝HZ_act_HS×0.55-27
Wherein,
HZ_cmpd_BS: determining the operating frequency of the first compressor 101 in HZ unit before the direct connection two-stage mode is operated;
before the first compressor 101 is started and operates in the direct connection double-stage operation mode, the operation frequency of the second compressor 102 is determined (the total heating capacity of the first compressor 101 during the direct connection double-stage operation is ensured to be basically equal to the heating capacity of the first compressor during the high-pressure stage operation, and after the compressor is started, the load and the water temperature do not obviously fluctuate), and the frequency HZ is unloaded before the first compressor 101 is started_cmpd_HSThe following: i.e., scheme n.
HZ_cmpd_HS＝(DIMP_BS/DIMP_HS)×HZ_cmps_BS/Ratio
Ratio＝0.0151*(T_sat_dsch_HS-T_sat_suct_HS)+(-0.0096×T_sat_dsch_HS+0.7769)
Wherein,
HZ_cmpd_HS: the operating frequency, in HZ, of the second compressor 102 determined prior to operation in the direct coupled dual stage mode;
DIMP_HS: displacement of the second compressor, dimensionless;
DIMP_LS: displacement of the first compressor, dimensionless;
HZ_cmpd_BS: the operating frequency, in HZ, of the first compressor 101 determined before the operation in the direct-coupled two-stage mode;
T_sat_dsch_HS: actual operating discharge saturation temperature of the second compressor 102, in units, when the second compressor 102 only is in the operating mode;
T_sat_suct_HS: actual operating suction saturation temperature, in units, of the second compressor 102 when only the second compressor 102 is operating in the mode;
the calculation formula of the load distribution (operating frequency) of the high first compressor in the direct-connection two-stage operating mode is as follows (the aim is to ensure that the load distribution of the high first compressor is reasonable, so that the exhaust gas of the first compressor completely enters the suction gas of the second compressor): discharge DIMP of second compressor_HSAnd a displacement DIMP of the first compressor_BSAfter the compressor of the system is well matched, i.e. a constant value, it is not changed any more, and the operation frequency of the first compressor is high, i.e. the exhaust saturation temperature T of the system is passed_cmpd_sat_dschSaturation temperature of inspiration T_cmpd_sat_suctTo be determined is the flow n
HZ_cmpd_BS＝(DIMP_HS/DIMP_BS)×HZ_cmpd_HS×Ratio
Ratio＝0.0151*(T_cmpd_sat_dsch-T_cmpd_sat_suct)+(-0.0096×T_cmpd-sat-dsch+0.7769)
Wherein,
HZ_cmpd_HS: the operating frequency, in HZ, of the second compressor 102 when operating in the direct-coupled two-stage mode;
HZ_cmpd_BS: when the direct connection two-stage mode is operated, the operating frequency of the first compressor 101 is in HZ unit;
DIMP_HS: displacement of the second compressor, dimensionless;
DIMP_LS: displacement of the first compressor, dimensionless;
T_cmpd_sat_dsch: the exhaust saturation temperature, in units, of the second compressor 102 when operating in the direct-coupled two-stage mode;
T_cmpd_sat_suct: when the direct connection two-stage mode is operated, the suction saturation temperature of the first compressor 101 is unit ℃;
and (c) switching from the direct connection double-stage operation mode to the operation mode of only the second compressor (when the aim is that the direct connection double-stage operation condition is not met, exiting the process c in time, if the unit operates in the direct connection double-stage operation mode, if all the conditions are not met:
(1) heating operation and ambient temperature TambLess than or equal to 2 ℃ and the water outlet temperature TlhwtThe temperature is more than or equal to 45 ℃ and the flow g is carried out;
(2)DT_act_cmpd-HS＞DT_cmpd_HSand the process i;
(3)HZ_act_HS> 150HZ and scheme i;
(4) if the loading requirement flow 5 exists, the unit is switched from the direct connection double-stage operation mode to a single-machine operation mode flow k in which only the second compressor 102 operates;
DT_cmpd_HS＝0.469×HZ_cmpd_HS-14.7
DT_act_cmpd_HS＝T_cmpd_sat_dsch-T_cmpd_sat_suct
wherein,
HZ_cmpd_HS: conditions to be met by the direct connection two-stage operation mode; unit degree C;
DT_act_cmpd_HS: when the direct-connection two-stage mode is operated, the actual exhaust and suction saturation temperature difference of the second compressor 102 is unit ℃;
T_cmpd_sat_dsch: when operating in the direct coupled dual stage mode, the discharge saturation temperature of the second compressor 102,unit degree C;
T_cmpd_sat_suct: when the direct connection two-stage mode is operated, the suction saturation temperature of the first compressor 101 is unit ℃;
when the first compressor 101 is turned off and the direct connection two-stage operation mode is exited, the operation mode is switched to the operation mode of only the second compressor 102, and after the first compressor 101 is turned off, the operation frequency HZ of the second compressor needs to be determined_act_HSThe following (aim: the heating capacity of the unit before and after the first compressor is closed is kept basically unchanged, so that the load and the water temperature do not fluctuate obviously): a process m;
HZ_act_HS＝(HZ_cmpd_BS+27)/0.54
wherein,
HZ_act_HS: determining the operating frequency of the second compressor 102 in HZ after exiting the dual-stage direct-connection operating mode;
HZ_cmpd_BS: before exiting the dual stage direct connection mode of operation, the operating frequency of the first compressor 101, in HZ.
The above-mentioned embodiments are merely illustrative and not restrictive, and those skilled in the art can make modifications to the embodiments without inventive contribution as required after reading the present specification, but only protected by the patent laws within the scope of the claims.
Claims (4)
1. A control method of an air-cooled screw heat pump system comprises the air-cooled screw heat pump system, and is characterized in that: the method comprises the control step of switching a single machine operation mode to a double machine parallel operation mode:
d1, closing the low-pressure exhaust stop valve (14); d2, unloading the first compressor (101) or the second compressor (102) being operated to a load; d3, loading the second compressor (102) or the first compressor (101) in the standby state to a load, so that the two compressors run to the same load; d4, the oil return electromagnetic valve (212) is opened after delaying for 5 seconds, and the bypass electromagnetic valve (29) is opened after delaying for 5 seconds.
2. The control method of an air-cooled screw heat pump system according to claim 1, characterized in that: the method comprises the following control steps of switching a double-click parallel mode to a single-compressor running mode: s1, selecting the compressor with longer running time in the first compressor (101) or the second compression molding machine (102) to stop; s2, closing the low-pressure exhaust stop valve (14); s3, loading the second compressor (102) or the first compressor (101) which is operated to a load; s4, the oil return electromagnetic valve (212) is closed, and the bypass electromagnetic valve (29) is closed.
3. The control method of the air-cooled screw heat pump system according to claim 2, characterized in that: comprising the control step of switching the second compressor mode to the direct connection bipolar operation mode: p1, opening a low-pressure exhaust stop valve (14); p2, unloading the second compressor (102) being operated to a specified load; p3, loading the first compressor (101) in the standby state; p4, after the first compressor (101) is started, the oil return electromagnetic valve (212) is started after 5 seconds of delay, and the bypass electromagnetic valve (29) is kept closed.
4. The control method of the air-cooled screw heat pump system according to claim 3, characterized in that: the method comprises the following control steps of switching a direct connection bipolar operation mode to a second compressor operation mode: a first compressor (101) shutdown comprising T1; t2, closing the low-pressure exhaust stop valve (14) after delaying for 2 seconds; t3, after the first compressor (101) is stopped, loading the second compressor (102) in the running state to a load; t4, the oil return solenoid valve (212) is closed, and the bypass solenoid valve (29) is closed.
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| CN201710976202.3A CN107860146A (en) | 2017-10-19 | 2017-10-19 | A kind of control method of air source heat pump system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117450623A (en) * | 2023-12-22 | 2024-01-26 | 珠海格力电器股份有限公司 | Compressor frequency control method and air conditioning unit |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2884061Y (en) * | 2005-12-23 | 2007-03-28 | 中国科学院理化技术研究所 | Parallel compressor low-temperature air source heat pump device capable of realizing two-stage compression |
| CN101029782A (en) * | 2007-04-12 | 2007-09-05 | 武汉新世界制冷工业有限公司 | Dual-locomotive and dual-stage screw refrigerating compressor set |
| CN104344589A (en) * | 2013-07-23 | 2015-02-11 | 约克广州空调冷冻设备有限公司 | Air source heat pump system and control method thereof |
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2017
- 2017-10-19 CN CN201710976202.3A patent/CN107860146A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2884061Y (en) * | 2005-12-23 | 2007-03-28 | 中国科学院理化技术研究所 | Parallel compressor low-temperature air source heat pump device capable of realizing two-stage compression |
| CN101029782A (en) * | 2007-04-12 | 2007-09-05 | 武汉新世界制冷工业有限公司 | Dual-locomotive and dual-stage screw refrigerating compressor set |
| CN104344589A (en) * | 2013-07-23 | 2015-02-11 | 约克广州空调冷冻设备有限公司 | Air source heat pump system and control method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117450623A (en) * | 2023-12-22 | 2024-01-26 | 珠海格力电器股份有限公司 | Compressor frequency control method and air conditioning unit |
| CN117450623B (en) * | 2023-12-22 | 2024-03-19 | 珠海格力电器股份有限公司 | Compressor frequency control method and air conditioning unit |
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Application publication date: 20180330 |