CN114440489A - Gas heat pump multi-connected unit air conditioning system and control method thereof - Google Patents
Gas heat pump multi-connected unit air conditioning system and control method thereof Download PDFInfo
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- CN114440489A CN114440489A CN202011579407.6A CN202011579407A CN114440489A CN 114440489 A CN114440489 A CN 114440489A CN 202011579407 A CN202011579407 A CN 202011579407A CN 114440489 A CN114440489 A CN 114440489A
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- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000004378 air conditioning Methods 0.000 title claims abstract description 32
- 239000000498 cooling water Substances 0.000 claims abstract description 191
- 239000003507 refrigerant Substances 0.000 claims abstract description 85
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 67
- 239000002918 waste heat Substances 0.000 claims abstract description 42
- 239000007789 gas Substances 0.000 claims abstract description 35
- 239000007788 liquid Substances 0.000 claims abstract description 22
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- 238000001704 evaporation Methods 0.000 claims abstract description 5
- 230000008020 evaporation Effects 0.000 claims abstract description 5
- 238000001816 cooling Methods 0.000 claims description 14
- 238000005057 refrigeration Methods 0.000 claims description 5
- 238000009833 condensation Methods 0.000 claims description 4
- 230000005494 condensation Effects 0.000 claims description 4
- 230000017525 heat dissipation Effects 0.000 claims description 4
- 230000033228 biological regulation Effects 0.000 claims description 3
- 230000004044 response Effects 0.000 claims description 2
- 238000005070 sampling Methods 0.000 claims description 2
- 238000001514 detection method Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 2
- 238000005485 electric heating Methods 0.000 abstract description 2
- 230000001681 protective effect Effects 0.000 abstract 1
- 230000008569 process Effects 0.000 description 25
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 12
- 239000003921 oil Substances 0.000 description 6
- 239000003345 natural gas Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 4
- 239000010687 lubricating oil Substances 0.000 description 3
- 239000002912 waste gas Substances 0.000 description 3
- 239000012530 fluid Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000003915 liquefied petroleum gas Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
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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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G5/00—Profiting from waste heat of combustion engines, not otherwise provided for
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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
- F25B39/00—Evaporators; Condensers
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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
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
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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
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
- F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Power Engineering (AREA)
- Combustion & Propulsion (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention discloses a gas heat pump multi-connected unit air conditioning system which comprises a refrigerant system and a cooling water system, wherein the refrigerant system comprises a compressor, an oil separator, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger, a waste heat recoverer I and a gas-liquid separator; the cooling water system comprises an engine, a waste heat recoverer I, a water pump I and a cooling water heat exchanger; the compressor is provided with a cooling water radiating pipe for preheating the compressor. Meanwhile, the invention also discloses a control method of the gas heat pump multi-connected unit air conditioning system. The invention optimizes the cooling water control, adds the first waste heat recoverer, reduces the cooling water temperature through the self-throttling evaporation of the refrigerant when the cooling water temperature is too high, avoids the problems of the too high cooling water temperature and the protective shutdown of the engine, simultaneously replaces the electric heating of the compressor by the high-temperature waste heat of the engine, and quickly preheats the compressor by the high-temperature waste heat of the engine under the low-temperature condition, thereby realizing the effects of quick startup and energy saving in heating.
Description
Technical Field
The invention relates to an air source heat pump air conditioning system, in particular to a gas heat pump multi-connected unit air conditioning system and a control method thereof.
Background
A Gas Engine Driven Heat Pump (GHP) system is an air conditioning system that uses Gas (including natural Gas, liquefied petroleum Gas, methane, etc.) as high-grade driving energy, and uses a Gas Engine to do work to directly drive an open-type compressor to work, thereby completing a vapor compression refrigeration cycle to achieve the purpose of refrigeration or heating. The practical application of the method has the following problems:
1) the engine generates heat energy by burning natural gas, so that the heat energy is converted into kinetic energy to drive the compressor to run, and the refrigeration cycle of the vapor compressor is realized, but a large amount of waste heat is generated in the combustion process of the engine, the waste heat must be taken away by engine cooling water and dissipated by a cooling water heat exchanger (or other ways), so that the outlet water temperature of the engine cooling water is kept at a certain value (for example, 85 ℃), and when the temperature of the engine cooling water is too high, the engine can limit the speed or stop the engine for protection, so that the working efficiency and the service life of the engine are influenced.
2) When the existing gas heat pump unit is started to operate under the low-temperature condition, a compressor heating belt must be started to perform preheating treatment firstly, and the starting operation can be performed only after the lubricating oil of the compressor reaches a certain temperature.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a gas heat pump multi-connected unit air conditioning system and a control method thereof.
In a first aspect, the present invention provides a gas heat pump multi-connected air conditioning system, including:
the cooling system comprises a refrigerant system and a cooling water system, wherein the refrigerant system comprises a compressor, an oil separator, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger, a first waste heat recoverer and a gas-liquid separator; the cooling water system comprises an engine, a waste heat recoverer I, a water pump I and a cooling water heat exchanger; the compressor is provided with a cooling water radiating pipe for preheating the compressor;
an exhaust port of the compressor is connected with a first port of a four-way valve through an oil separator, a second port of the four-way valve is connected with one end of an outdoor heat exchanger, the other end of the outdoor heat exchanger is divided into two paths after passing through an electronic expansion valve EXV1, one path is sequentially connected with a third port of the four-way valve after passing through the electronic expansion valve EXV3 and an indoor heat exchanger, the other path is sequentially connected with a suction port of the compressor through an electronic expansion valve EXV2, a cold side of a waste heat recoverer and a gas-liquid separator, and a fourth port of the four-way valve is connected with the suction port of the compressor through the gas-liquid separator;
the engine cooling water outlet is connected with the engine cooling water inlet through an electromagnetic valve SV6, a cooling water heat exchanger and a water pump I in sequence to form an air cooling loop, the engine cooling water outlet is connected with the engine cooling water inlet through an electromagnetic valve SV5, a hot side of a waste heat recoverer and a water pump I in sequence to form a refrigerant cooling loop, and the engine cooling water outlet is connected with the engine cooling water inlet through an electromagnetic valve SV8, a cooling water radiating pipe of a compressor and a water pump I in sequence to form a compressor preheating loop.
In a second aspect, the invention provides a control method based on the gas heat pump multi-connected unit air conditioning system, which includes:
when the compressor is used for heating in winter, the compressor is preheated by high-temperature cooling water when the engine enters an idling state, so that the compressor can quickly reach a starting condition to perform heating operation;
when the system is in refrigeration operation and the cooling water heat exchanger fan works in full load, and the outlet water temperature of the engine cooling water still exceeds a normal interval, the cooling water is subjected to heat exchange and cooling by using a refrigerant of a refrigerant system;
when the system is in heating operation and the cooling water heat exchanger fan works in full load, and the outlet water temperature of the engine cooling water still exceeds a normal interval, the cooling water is subjected to heat exchange and cooling by using a refrigerant of the refrigerant system.
Compared with the prior art, the invention has the beneficial effects that:
(1) the control of cooling water is optimized, the first waste heat recoverer is added, when the temperature of the cooling water is too high, the temperature of the cooling water is reduced through self-throttling evaporation of a refrigerant, and the problems that the temperature of the cooling water is too high and an engine is protected to stop are solved.
(2) The high-temperature waste heat of the engine replaces the electric heating of the compressor, and the high-temperature waste heat of the engine is utilized to quickly preheat the compressor under the low-temperature condition, so that the effects of quick starting and energy saving during heating are realized.
Drawings
Fig. 1 is a schematic structural diagram of a gas heat pump multi-split air conditioning system.
Fig. 2 is a compressor preheating schematic diagram when the gas heat pump multi-split air conditioning system freezer is started.
Fig. 3 is a compressor preheating control flow chart when the gas heat pump multi-split air conditioning system freezer is started.
FIG. 4 is a schematic diagram of cooling water temperature reduction in the cooling operation of the gas heat pump multi-split air conditioning system.
Fig. 5 is a schematic diagram of the gas heat pump multi-split air conditioning system for reducing the temperature of cooling water during heating operation.
Fig. 6 is a flow chart of control for reducing the temperature of cooling water in the gas heat pump multi-split air conditioning system.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of embodiments of the present invention, and not all embodiments.
In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or as implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In addition, the definition of hot side and cold side in the present invention is: the heat of the hot side is transferred to the cold side, the fluid flowing through the hot side releases heat and lowers the temperature, and the fluid flowing through the cold side absorbs heat and raises the temperature.
Examples
As shown in fig. 1, the gas heat pump multi-split air conditioning system of the present invention includes a refrigerant system and a cooling water system.
The refrigerant system comprises a compressor 1, an oil separator 2, a four-way valve 3, an outdoor heat exchanger 4, an indoor heat exchanger 5, a waste heat recoverer I6, a gas-liquid separator 7, temperature sensors T1-T5, electronic expansion valves EXV 1-EXV 3, electromagnetic valves SV 1-SV 4 and a stop valve BV1/BV2, wherein a cooling water radiating pipe used for preheating the compressor 1 is attached to the surface of the compressor.
The cooling water system comprises an engine 8, a waste heat recoverer I6, a water pump I9, a cooling water heat exchanger 10, a filter I11, a waste heat recoverer II 12, a water pump II 13, a filter II 14, a hot water tank 15, a temperature sensor T6/T7 and electromagnetic valves SV 5-SV 9.
An exhaust port of a compressor 1 is connected with a first port of a four-way valve 3 through an oil separator 2, a second port of the four-way valve 3 is connected with one end of an outdoor heat exchanger 4, the other end of the outdoor heat exchanger 4 is divided into two paths after passing through an electronic expansion valve EXV1, one path is connected with a third port of the four-way valve 3 after sequentially passing through a stop valve BV1, an electronic expansion valve EXV3, an indoor heat exchanger 5 and a stop valve BV2, the other path is connected with an air suction port of the compressor 1 sequentially passing through an electronic expansion valve EXV2, a first cold side of a waste heat recoverer 6 and a gas-liquid separator 7, and a fourth port of the four-way valve 3 is connected with the air suction port of the compressor 1 through the gas-liquid separator 7.
The cooling water outlet of the engine 8 is divided into five paths, and the first path returns to the cooling water inlet of the engine 8 through an electromagnetic valve SV6, a cooling water heat exchanger 10, a first filter 11 and a first water pump 9 in sequence to form an air cooling loop; the second path returns to a cooling water inlet of the engine 8 through an electromagnetic valve SV5, a hot side of a waste heat recoverer I6, a filter I11 and a water pump I9 to form a refrigerant cooling loop; the third path of the refrigerant returns to a cooling water inlet of the engine 8 through an electromagnetic valve SV8, a cooling water radiating pipe on the surface of the compressor 1, a filter I11 and a water pump I9 in sequence to form a compressor preheating loop; the fourth path returns to a cooling water inlet of the engine 8 through an electromagnetic valve SV9, a hot side of a waste heat recoverer II 12, a filter I11 and a water pump I9 in sequence to form a waste heat utilization loop; and the fifth path returns to the cooling water inlet of the engine 8 through an electromagnetic valve SV7, a filter I11 and a water pump I9 in sequence to form a self-circulation loop. The cold side of the waste heat recoverer II 12, the water pump II 13, the filter II 14 and the hot water tank 15 are sequentially connected to form a hot water loop.
The temperature sensor T1 is used for monitoring the exhaust temperature of the compressor 1, the temperature sensor T5 is used for monitoring the air suction temperature of the compressor 1, the temperature sensor T6 is used for monitoring the outlet water temperature of the cooling water of the engine 8, and the temperature sensor T7 is used for monitoring the inlet water temperature of the cooling water of the engine 8.
As shown in fig. 2, when the gas heat pump multi-split air conditioning system of the present invention performs heating operation in winter, the compressor may be preheated by using high-temperature cooling water of the engine entering an idle state, so that the compressor quickly reaches a starting condition to perform heating operation, and the specific steps are as follows:
the inside burning natural gas of engine 8 produces a large amount of heats, and heat energy conversion drives compressor 1 operation through the belt pulley into mechanical energy, and the cooling water absorbs the high temperature waste gas that is discharged by the engine 8 internal unit and becomes high temperature cooling water, then divides into two the tunnel: one path of cooling water passes through an opened electromagnetic valve SV8, and exchanges heat with the compressor 1 in a low-temperature state through a cooling water radiating pipe attached to the surface of the compressor 1, so that the temperature of the compressor 1 is gradually increased, and then the cooling water returns to a suction position of a water pump I9 through a one-way valve and a filter I11, is compressed and pressurized through the water pump I9 and returns to a cooling water inlet of the engine 8; another way gets into cooling water heat exchanger 10 through the solenoid valve SV6 that opens, the unnecessary heat of cooling water is through carrying out the heat exchange with the air, in the middle of loosing the air, through adjusting the fan rotational speed height, the control is scattered the heat size in the middle of the air to guarantee that the cooling water goes out the water temperature and keep in normal interval, the cooling water is through cooling water heat exchanger 10 and carries out the heat transfer back, join with the cooling water of the first way, get back to engine 8 through a 9 operation of water pump and carry out the heat transfer once more, so circulation.
As shown in fig. 3, the control flow of the gas heat pump multi-split air conditioning system according to the present invention to preheat the compressor by the high temperature cooling water of the engine is as follows:
firstly, step S01, the gas heat pump outdoor unit is in a stop state, then step S02 is carried out to check whether a starting signal exists, step S01 is carried out if the starting signal does not exist, the stop state is continuously kept, step S03 is carried out if the starting signal exists, electromagnetic valve SV6 is opened, the engine is ignited and operated to an idle state, the cooling water heat exchanger normally operates, step S04 is carried out to detect whether the temperature of the compressor is less than or equal to a preheating judgment value, step S09 is carried out to close electromagnetic valve SV8 if the temperature of the compressor is detected to be higher than the preheating judgment value, step S10 is carried out to attract the compressor clutch, and the unit normally operates; if the temperature of the compressor is detected to be less than or equal to a preheating judgment value, the process goes to step S05 to open an electromagnetic valve SV8, the compressor is preheated by high-temperature cooling water of the engine, then the process goes to step S07 to detect whether the outlet water temperature of the cooling water is greater than the upper limit value of a normal interval, if so, the process goes to step S06 to increase the gear of a fan of a cooling water heat exchanger by 1, the process returns to step S07 to detect again after waiting for 30S, if not, the process goes to step S08 to detect whether the outlet water temperature of the cooling water is less than the lower limit value of the normal interval, if so, the process goes to step S11 to decrease the gear of the fan of the cooling water heat exchanger by 1, the process returns to step S08 to detect again after waiting for 30S, otherwise, the process returns to step S04, the process is circulated in such a way until the temperature of the compressor is greater than the preheating judgment value, the step S09 to close the electromagnetic valve SV8, and then the step S10 to attract the compressor clutch, and the unit operates normally.
As shown in fig. 4, when the gas heat pump multi-split air conditioning system of the present invention operates in a cooling mode, engine cooling water is cooled by a cooling water heat exchanger, and when a fan is in full-load operation and the temperature of the engine cooling water still exceeds a normal range, the cooling water is cooled by heat exchange with a refrigerant of a refrigerant system, and the specific steps are as follows:
firstly, natural gas is combusted in the cooling water system engine 8 to generate a large amount of heat, the heat energy is converted into mechanical energy to drive the compressor 1 to run through the belt pulley, the cooling water absorbs high-temperature waste gas discharged by the engine 8 and becomes high-temperature cooling water, and then the cooling water is divided into two paths: one path of the cooling water enters a waste heat recoverer I6 through an opened electromagnetic valve SV5, high-temperature cooling water is subjected to heat exchange with a low-temperature low-pressure refrigerant throttled by an electronic expansion valve EXV2 in the waste heat recoverer I6, a large amount of heat is dissipated into the refrigerant of a refrigerant system, and the cooling water coming out of the waste heat recoverer I6 returns to a cooling water inlet of an engine 8 through a filter I11 and a water pump I9; the other path of cooling water enters the cooling water heat exchanger 10 through an opened electromagnetic valve SV6, part of redundant heat of high-temperature cooling water is dissipated into the air through heat exchange with the air, the heat dissipated into the air is controlled by adjusting the rotating speed of the fan, the cooling water coming out of the cooling water heat exchanger 10 is converged with the first path of cooling water, and then is operated to return to the engine 8 through the first water pump 9 for heat exchange again, and the circulation is carried out, so that the temperature of the outlet water of the cooling water is kept in a normal interval.
Meanwhile, a compressor 1 of the refrigerant system compresses low-temperature low-pressure gaseous refrigerants, discharges high-temperature high-pressure gaseous refrigerants, separates compressor lubricating oil brought out by the refrigerants through an oil separator 2, then the high-temperature high-pressure gaseous refrigerants enter an outdoor heat exchanger 4 (a condenser at the moment) through a four-way valve 3 to be subjected to heat dissipation and condensation to become high-temperature high-pressure liquid refrigerants, and the high-temperature high-pressure gaseous refrigerants are divided into two paths after passing through a fully-opened electronic expansion valve EXV 1: one path of refrigerant passes through a stop valve BV1, is throttled and decompressed by an electronic expansion valve EXV3 and then is changed into low-temperature and low-pressure refrigerant to exchange heat with an indoor heat exchanger 5 (an evaporator at the moment) for evaporation, so that the indoor temperature is reduced, and then the refrigerant returns to a gas-liquid separator 7 through a stop valve BV2 and a four-way valve 3; the other path is throttled and decompressed by an electronic expansion valve EXV2 to become a low-temperature low-pressure gaseous refrigerant, the low-temperature low-pressure gaseous refrigerant is collected in a waste heat recoverer 6 to exchange heat, the heat of high-temperature cooling water is absorbed, the temperature of the cooling water is reduced, then the high-temperature cooling water returns to a gas-liquid separator 7 to be converged with the first path of refrigerant, and finally returns to a suction port of the compressor 1 to circulate.
As shown in fig. 5, when the gas heat pump multi-split air conditioning system of the present invention operates in heating mode, engine cooling water is cooled by a cooling water heat exchanger, when a fan is in full-load operation and the temperature of the engine cooling water still exceeds a normal range, the cooling water is cooled by heat exchange with a refrigerant of a refrigerant system, and the specific steps are as follows:
firstly, natural gas is combusted in the cooling water system engine 8 to generate a large amount of heat, the heat energy is converted into mechanical energy to drive the compressor 1 to run through the belt pulley, the cooling water absorbs high-temperature waste gas discharged by the engine 8 and becomes high-temperature cooling water, and then the cooling water is divided into two paths: one path of the cooling water enters a waste heat recoverer I6 through an opened electromagnetic valve SV5, high-temperature cooling water is subjected to heat exchange with a low-temperature low-pressure refrigerant throttled by an electronic expansion valve EXV2 in the waste heat recoverer I6, a large amount of heat is dissipated into the refrigerant of a refrigerant system, and the cooling water coming out of the waste heat recoverer I6 returns to a cooling water inlet of an engine 8 through a filter I11 and a water pump I9; the other path of cooling water enters the cooling water heat exchanger 10 through an opened electromagnetic valve SV6, part of redundant heat of high-temperature cooling water is dissipated into the air through heat exchange with the air, the heat dissipated into the air is controlled by adjusting the rotating speed of the fan, the cooling water coming out of the cooling water heat exchanger 10 is converged with the first path of cooling water, and then is operated to return to the engine 8 through the first water pump 9 for heat exchange again, and the circulation is carried out, so that the temperature of the outlet water of the cooling water is kept in a normal interval.
Meanwhile, in the refrigerant system, the condenser and the evaporator are exchanged, the outdoor heat exchanger 4 serves as the condenser, the indoor heat exchanger 5 serves as the evaporator in fig. 4, the indoor heat exchanger 5 serves as the condenser, and the outdoor heat exchanger 4 serves as the evaporator in fig. 5. Specifically, the method comprises the following steps: compressor 1 compresses low temperature low pressure gaseous refrigerant, discharges high temperature high pressure gaseous refrigerant, separates the compressor lubricating oil that is taken out by the refrigerant through oil separator 2, then, high temperature high pressure gaseous refrigerant gets into indoor heat exchanger 5 (for the condenser this moment) through cross valve 3, stop valve BV2 and carries out the heat dissipation condensation and become high temperature high pressure liquid refrigerant to make indoor side temperature rise, then divide into two the tunnel behind full open electronic expansion valve EXV3, stop valve BV 1: one path of the refrigerant is throttled and decompressed by an electronic expansion valve EXV1 to become a low-temperature and low-pressure refrigerant, exchanges heat with an outdoor heat exchanger 4 (an evaporator at the moment) for evaporation, and then returns to the gas-liquid separator 7 through a four-way valve 3; the other path is throttled and decompressed into low-temperature and low-pressure gaseous refrigerant through an electronic expansion valve EXV2, the low-temperature and low-pressure gaseous refrigerant is collected in a waste heat recoverer 6 to exchange heat, the heat of high-temperature cooling water is absorbed, the temperature of the cooling water is reduced, then the cooling water returns to a gas-liquid separator 7 to be merged with the first path of refrigerant, and finally the cooling water returns to a suction port of the compressor 1 to circulate.
As shown in fig. 6, the control flow of the gas heat pump multi-split air conditioning system of the present invention for exchanging heat and reducing temperature of cooling water by the refrigerant of the refrigerant system is as follows:
firstly, when the gas heat pump outdoor unit is under normal control in step S12, the process proceeds to step S13 to detect whether the temperature of the outlet water of the cooling water is greater than a protection starting value, if the temperature is less than or equal to the protection starting value, the process returns to step S12 to still maintain normal control, if the temperature is greater than or equal to the protection starting value, the process proceeds to step S14 to detect whether the electromagnetic valve SV6 is opened, the electromagnetic valve SV5/SV7/SV8/SV9 is closed, if the temperature is not greater than the protection starting value, the process proceeds to step S19 to open SV6, the process closes SV5/SV7/SV8/SV9 to operate, after waiting for 1min, the process proceeds to step S13 again to circulate, if the process proceeds to step S15 to open the electromagnetic valve SV5 and adjust the electronic expansion valve EXV2 to an initial opening degree, the cooling water is cooled by using a refrigerant, then the process proceeds to step S16 to detect whether the suction superheat degree of the compressor is equal to a set superheat degree, if the compressor is not equal to the set superheat degree, the process proceeds to step S20 to adjust the opening degree of the PI control of the electronic expansion valve EXV2, after waiting for 1min, the process again enters step S16 for circulation, if yes, the process enters step S17 for detecting whether the cooling water outlet temperature is less than or equal to a protection closing value, when the cooling water outlet temperature is detected to be greater than the protection closing value, the process enters step S21 for keeping the current state control, after waiting for 1min, the process again enters step S17 for judgment circulation, when the cooling water outlet temperature is detected to be less than or equal to the protection closing value, the process enters step S18 for closing the SV5 electromagnetic valve, then the process returns to step S12 again, and the process enters the normal control of the gas heat pump outdoor unit.
The entering PI control to regulate the opening degree of the electronic expansion valve EXV2 specifically comprises the following steps: the opening degree variation Δ P is Δ P1 +. Δ P2. The delta P1 is subjected to PI control regulation according to the suction superheat degree of the compressor, and a delta P1 expression is as follows: Δ P1 is a (e-e1) + B (Δ T/TIC) (e + e1), where e is the current intake superheat — the set intake superheat (the deviation of the intake superheat), e1 is e of the previous time, Δ T is the sampling period, TIC is the integral response time constant, a is the proportional coefficient, and B is the integral coefficient.
The delta P2 is subjected to PI control regulation according to the exhaust temperature of the compressor, and a delta P2 expression is as follows: Δ P2 ═ C (T1-T1), the above formula indicates that T1 is the current exhaust temperature, T1 is the last cycle exhaust temperature, and C is the proportionality coefficient.
The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and not to limit the protection scope of the present invention accordingly. All equivalent changes and modifications made according to the spirit of the present disclosure should be covered within the scope of the present disclosure.
Claims (10)
1. The utility model provides a gas heat pump multi-connected unit air conditioning system which characterized in that: the system comprises a refrigerant system and a cooling water system, wherein the refrigerant system comprises a compressor, an oil separator, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger, a first waste heat recoverer and a gas-liquid separator; the cooling water system comprises an engine, a waste heat recoverer I, a water pump I and a cooling water heat exchanger; the compressor is provided with a cooling water radiating pipe for preheating the compressor;
an exhaust port of the compressor is connected with a first port of a four-way valve through an oil separator, a second port of the four-way valve is connected with one end of an outdoor heat exchanger, the other end of the outdoor heat exchanger is divided into two paths after passing through an electronic expansion valve EXV1, one path is sequentially connected with a third port of the four-way valve after passing through the electronic expansion valve EXV3 and an indoor heat exchanger, the other path is sequentially connected with a suction port of the compressor through an electronic expansion valve EXV2, a cold side of a waste heat recoverer and a gas-liquid separator, and a fourth port of the four-way valve is connected with the suction port of the compressor through the gas-liquid separator;
the engine cooling water outlet is connected with the engine cooling water inlet through an electromagnetic valve SV6, a cooling water heat exchanger and a water pump I in sequence to form an air cooling loop, the engine cooling water outlet is connected with the engine cooling water inlet through an electromagnetic valve SV5, a hot side of a waste heat recoverer and a water pump I in sequence to form a refrigerant cooling loop, and the engine cooling water outlet is connected with the engine cooling water inlet through an electromagnetic valve SV8, a cooling water radiating pipe of a compressor and a water pump I in sequence to form a compressor preheating loop.
2. The gas heat pump multi-connected unit air conditioning system as claimed in claim 1, wherein: the cooling water radiating pipe is attached to the surface of the compressor.
3. The gas heat pump multi-connected unit air conditioning system as claimed in claim 1, wherein: the cooling water system also comprises a waste heat recoverer II, a water pump II and a hot water tank; the engine cooling water outlet is connected with the engine cooling water inlet through an electromagnetic valve SV9, a hot side of a waste heat recoverer II and a water pump I in sequence to form a waste heat utilization loop, and a cold side of the waste heat recoverer II, a water pump II and a hot water tank are connected in sequence to form a hot water loop.
4. The gas heat pump multi-connected unit air conditioning system as claimed in claim 1, wherein: and the engine cooling water outlet is also sequentially connected with the engine cooling water inlet through an electromagnetic valve SV7 and a water pump I to form a self-circulation loop.
5. The gas heat pump multi-connected unit air conditioning system as claimed in claim 2, wherein: the water inlet side of the first water pump is provided with a first filter, and the water inlet side of the second water pump is provided with a second filter.
6. The control method of the gas heat pump multi-connected unit air conditioning system based on any one of claims 1 to 5 is characterized in that: when heating operation in winter, utilize the engine to get into the high temperature cooling water of idle state and preheat the compressor to make the compressor reach the starting condition fast, heat the operation, specifically include:
high-temperature cooling water generated by the engine is divided into two paths after coming out from a cooling water outlet of the engine: one path enters a cooling water radiating pipe attached to the surface of the compressor through an electromagnetic valve SV8, exchanges heat with the compressor in a low-temperature state to gradually increase the temperature of the compressor, and returns to an engine cooling water inlet through a water pump; the other path enters a cooling water heat exchanger through an electromagnetic valve SV6 to exchange heat with air, the heat quantity dispersed into the air is controlled by adjusting the rotating speed of a fan, the temperature of the outlet water of the cooling water is kept in a normal interval, and then the outlet water of the cooling water is converged with the first path of cooling water and returned to an engine cooling water inlet through a water pump.
7. The control method of the gas heat pump multi-connected unit air conditioning system as claimed in claim 6, wherein: the control flow for preheating the compressor by using the high-temperature cooling water when the engine enters the idle state comprises the following steps:
1) the engine is ignited to run to an idle speed state, and the cooling water heat exchanger runs normally;
2) detecting whether the temperature of the compressor is less than or equal to a preheating judgment value, if not, turning to the step 6), and if so, turning to the step 3);
3) opening an electromagnetic valve SV8, and preheating a compressor by using high-temperature cooling water of an engine;
4) detecting whether the outlet water temperature of the cooling water is kept within a normal interval, if so, returning to the step 2), and if not, entering the step 5);
5) if the outlet water temperature of the cooling water is higher than the upper limit value of the normal interval, increasing the gear of a fan of the cooling water heat exchanger, if the outlet water temperature of the cooling water is lower than the lower limit value of the normal interval, reducing the gear of the fan of the cooling water heat exchanger, and returning to the step 4 after the gear of the fan is adjusted);
6) and (4) closing the electromagnetic valve SV8, closing a compressor clutch, and normally operating the unit.
8. The control method of the gas heat pump multi-connected unit air conditioning system as claimed in claim 6, wherein: when system refrigeration operation and cooling water heat exchanger fan full load during operation, when engine cooling water goes out water temperature and still surpasss normal interval, utilize refrigerant system's refrigerant to carry out the heat transfer cooling to the cooling water, specifically include:
high-temperature cooling water generated by the engine is divided into two paths after coming out of a cooling water outlet of the engine, one path of the high-temperature cooling water enters a first waste heat recoverer through an electromagnetic valve SV5, exchanges heat with low-temperature and low-pressure refrigerant throttled by an electronic expansion valve EXV2, dissipates heat into the refrigerant of a refrigerant system, and then returns to the cooling water inlet of the engine through a water pump; the other path enters a cooling water heat exchanger through an electromagnetic valve SV6 to exchange heat with air, the heat quantity dispersed in the air is controlled by adjusting the rotating speed of a fan, the temperature of the outlet water of the cooling water is kept in a normal interval, and then the outlet water of the cooling water is converged with the first path of cooling water and returned to an engine cooling water inlet through a water pump;
the high-temperature high-pressure gaseous refrigerant discharged by the compressor enters an outdoor heat exchanger through an oil separator and a four-way valve to be subjected to heat dissipation and condensation to be changed into a high-temperature high-pressure liquid refrigerant, and the refrigerant is divided into two paths after passing through a fully-opened electronic expansion valve EXV 1: one path of the refrigerant is throttled and decompressed by an electronic expansion valve EXV3 and then is changed into a low-temperature low-pressure refrigerant to exchange heat and evaporate with an indoor heat exchanger, so that the indoor temperature is reduced, and then the refrigerant returns to the gas-liquid separator through a four-way valve; the other path of refrigerant is throttled and decompressed by an electronic expansion valve EXV2 to become a low-temperature low-pressure gaseous refrigerant, enters a waste heat recoverer to absorb the heat of high-temperature cooling water, so that the temperature of the cooling water is reduced, then returns to the gas-liquid separator to be converged with the first path of refrigerant, and finally returns to the air suction port of the compressor.
9. The control method of the gas heat pump multi-connected unit air conditioning system as claimed in claim 6, wherein: when the system heats the operation, and when cooling water heat exchanger fan full load work, when engine cooling water goes out water temperature and still surpasss normal interval, utilize refrigerant system's refrigerant to carry out the heat transfer cooling to the cooling water, specifically include:
high-temperature cooling water generated by the engine is divided into two paths after coming out of a cooling water outlet of the engine, one path of the high-temperature cooling water enters a first waste heat recoverer through an electromagnetic valve SV5, exchanges heat with low-temperature and low-pressure refrigerant throttled by an electronic expansion valve EXV2, dissipates heat into the refrigerant of a refrigerant system, and then returns to the cooling water inlet of the engine through a water pump; the other path enters a cooling water heat exchanger through an electromagnetic valve SV6 to exchange heat with air, the heat quantity dispersed in the air is controlled by adjusting the rotating speed of a fan, the temperature of the outlet water of the cooling water is kept in a normal interval, and then the outlet water of the cooling water is converged with the first path of cooling water and returned to an engine cooling water inlet through a water pump;
the high-temperature high-pressure gaseous refrigerant discharged by the compressor enters the indoor heat exchanger through the oil separator and the four-way valve to be subjected to heat dissipation and condensation to be changed into a high-temperature high-pressure liquid refrigerant, so that the indoor temperature is increased, and then the refrigerant is divided into two paths through the fully-opened electronic expansion valve EXV 3: one path of the refrigerant is throttled and decompressed by an electronic expansion valve EXV1 to become a low-temperature and low-pressure refrigerant, exchanges heat with an outdoor heat exchanger for evaporation, and then returns to the gas-liquid separator through a four-way valve; the other path of refrigerant is throttled and decompressed by an electronic expansion valve EXV2 to become a low-temperature low-pressure gaseous refrigerant, enters a waste heat recoverer to absorb the heat of high-temperature cooling water, so that the temperature of the cooling water is reduced, then returns to the gas-liquid separator to be converged with the first path of refrigerant, and finally returns to the air suction port of the compressor.
10. The control method of the gas heat pump multi-connected air conditioning system according to claim 8 or 9, wherein: the control flow for exchanging heat and reducing temperature of the cooling water by using the refrigerant of the refrigerant system comprises the following steps:
1) detecting whether the temperature of the cooling water outlet of the engine is higher than a protection starting value, if not, keeping the current state control, waiting for 1min, then carrying out detection judgment again, and if so, turning to the step 2);
2) detecting whether an electromagnetic valve SV6 is opened or not, closing the electromagnetic valve SV5/SV7/SV8/SV9, and if not, performing step 3), and if so, entering step 4);
3) executing the actions of opening the solenoid valve SV6 and closing the solenoid valve SV5/SV7/SV8/SV9, and entering the step 4);
4) opening an electromagnetic valve SV5, adjusting an electronic expansion valve EXV2 to an initial opening degree, and performing heat exchange and cooling on cooling water by using a refrigerant;
5) detecting whether the suction superheat degree of the air suction port of the compressor is equal to the set superheat degree, if not, entering step 6), and if so, entering step 7)
6) Adjusting the electronic expansion valve EXV2 through PI control, and returning to step 5) after adjustment, wherein the opening variation Δ P of the electronic expansion valve EXV2 is Δ P1 +/Δ P2;
the delta P1 is PI control adjustment according to the suction superheat degree: Δ P1 ═ a (e-e1) + B ([ delta ] T/TIC) ([ delta ] e1), where e is the deviation value of the degree of superheat of inspiration, e1 is the last e, Δ T is the sampling period, TIC is the integral response time constant, a is the proportional coefficient, and B is the integral coefficient;
and (3) performing PI control regulation according to the exhaust temperature of the compressor by delta P2: Δ P2 ═ C (T1-T1), where T1 is the current exhaust temperature, T1 is the exhaust temperature of the previous cycle, and C is the proportionality coefficient.
7) Detecting whether the outlet water temperature of the cooling water of the engine is less than or equal to a protection closing value, if not, keeping the current state control, waiting for 1min, then detecting and judging again, if so, entering the step 8)
8) Solenoid valve SV5 is closed, return to step 1).
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