CN210399609U - CO2 heat pump system - Google Patents
CO2 heat pump system Download PDFInfo
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- CN210399609U CN210399609U CN201921219917.5U CN201921219917U CN210399609U CN 210399609 U CN210399609 U CN 210399609U CN 201921219917 U CN201921219917 U CN 201921219917U CN 210399609 U CN210399609 U CN 210399609U
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Abstract
The utility model discloses a CO2A heat pump system relates to the technical field of air source heat pump systems. The defrosting device is used for solving the problem that the existing air source heat pump system is low in defrosting speed. The utility model comprises CO2Refrigerant circulation path and water supply circulation path, CO2The refrigerant circulation path comprises a compressor, a gas cooler, a first throttling device and an evaporator which are sequentially connected end to end, the water supply circulation path comprises a water tank and a water path connecting pipe assembly, the water path connecting pipe assembly comprises a cold water supply pipe, a hot water return pipe, a water path control valve and a hot water supply pipe, a water inlet of the water tank is communicated with a hot water supply pipe, a water return opening of the water tank is communicated with the hot water return pipe, a water inlet of the gas cooler, a cold water supply pipe, a hot water return pipeThe water supply pipe is communicated with a water outlet of the gas cooler, and the waterway control valve is used for controlling the water inlet of the gas cooler to be communicated or disconnected with the cold water supply pipe and controlling the water inlet of the gas cooler to be communicated or disconnected with the hot water return pipe.
Description
Technical Field
The utility model relates to a relevant technical field of air source heat pump system especially relates to a CO2A heat pump system.
Background
The air source heat pump system absorbs low-temperature heat in air by utilizing a heat transfer working medium, and the low-temperature heat is converted into high-temperature heat after being compressed by a compressor so as to heat water temperature. Due to CO2Is a heat transfer working medium existing in nature, and CO2Has an ODP of 0(Ozone Depletion Potential) and a GWP of 1(Global Warming Potential), and CO is present in cases where flammability and toxicity are severely limited2Is a very ideal refrigerant, and the high exhaust temperature and temperature slippage of the transcritical cycle are very suitable for the heating of water, so that CO2The heat pump system has good application prospect.
Due to CO2Heat pump systems employ heat pumps in the form of air sources and therefore they still suffer from frost formation. When CO is present2When the heat pump system operates under the conditions of low outdoor temperature and high humidity, the surface of the air side evaporator is easy to frost, and when the surface of the air side evaporator frosts, the air side evaporator needs to be defrosted.
For CO2For heat pump systems, CO2The whole operation pressure of the heat pump system is higher, and a proper four-way valve component is not available, so that the four-way valve reversing defrosting is not suitable for CO2Defrosting of the heat pump system; in addition, hot gas bypass defrost is used to defrost CO2When the heat pump system is used for defrosting, the heat for defrosting is derived from the heat storage of the shell of the compressor and the power consumption of the compressor during operation, the available heat for defrosting is very little, so the defrosting needs to consume a long time, and after hot gas bypass defrosting is started, CO is used2The only high-low pressure difference of the heat pump system comes from CO2Resistance loss of piping components in heat pump systems due to CO2The pressure difference caused by pipeline parts in the heat pump system is extremely small, so that the high-low pressure difference of a compressor during defrosting is very small, and the exhaust pressureThe temperature of the exhaust gas is low, so that the temperature of the refrigerant at the inlet of the evaporator is further reduced, the defrosting time is longer, and therefore when the frosting is serious, the hot gas bypass defrosting time is longer, and the user experience is seriously influenced.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a CO2The heat pump system is used for solving the problems of low defrosting speed and long defrosting time of the conventional air source heat pump system.
To achieve the above object, the embodiment of the present invention provides a CO2The heat pump system comprises a CO2A refrigerant circulation path and a water supply circulation path, the CO2The refrigerant circulating passage comprises a compressor, a gas cooler, a first throttling device and an evaporator which are sequentially connected end to end, the water supply circulation passage comprises a water tank and a water path connecting pipe assembly, the water tank is provided with a water inlet and a water return port, the waterway connecting pipe component comprises a cold water supply pipe, a hot water return pipe, a waterway control valve and a hot water supply pipe, the water inlet of the water tank is communicated with the hot water supply pipe, the water return port of the water tank is communicated with the hot water return pipe, the water inlet of the gas cooler, the cold water supply pipe, the hot water return pipe and the waterway control valve are all connected, the water supply pipe is communicated with a water outlet of the gas cooler, and the waterway control valve is used for controlling the water inlet of the gas cooler to be communicated or disconnected with the cold water supply pipe and controlling the water inlet of the gas cooler to be communicated or disconnected with the hot water return pipe.
On the other hand, the embodiment of the utility model provides a still provide one kind and be used for above-mentioned CO2The defrosting control method of the heat pump system comprises the following steps: when CO is detected2When the heat pump system reaches a first defrosting condition, the first throttling device is opened, the water path control valve controls the water inlet of the gas cooler to be communicated with the hot water return pipe, the first defrosting condition at least comprises that the suction pressure of the compressor exceeds a first preset pressure range, and the duration time that the suction pressure of the compressor exceeds the first preset pressure range reachesTo a first preset time.
Compared with the prior art, the embodiment of the utility model provides a CO2Heat pump system and defrosting control method thereof, wherein, CO2The water supply circulation path in the heat pump system comprises a water tank and a water path connecting pipe assembly, a water inlet and a water return port are formed in the water tank, the water path connecting pipe assembly comprises a cold water supply pipe, a hot water return pipe, a water path control valve and a hot water supply pipe, the water inlet and the hot water supply pipe of the water tank are communicated, the water return port of the water tank is communicated with the hot water return pipe, the water inlet, the cold water supply pipe, the hot water return pipe and the water path control valve of a gas cooler are all connected, the hot water supply pipe is communicated with the water outlet of the gas cooler, and the water path control valve is used for controlling the water inlet of the gas cooler and. When CO is present2When the heat pump system is used for heating water in the water tank, the water path control valve controls the water inlet of the gas cooler to be communicated with the cold water supply pipe, cold water flows into the gas cooler, and at the moment, high-temperature and high-pressure refrigerant (namely CO) discharged by the compressor2Refrigerant) can transfer heat to cold water flowing in from a water inlet of the gas cooler when passing through the gas cooler, thereby heating the water. When the above-mentioned CO is present2When the heat pump system is used for defrosting, if the suction pressure of the compressor is detected to exceed a first preset pressure range and the duration that the suction pressure of the compressor exceeds the first preset pressure range reaches a first preset time, CO2The heat pump system reaches a first defrosting condition, namely, the duration that the suction pressure of the compressor exceeds a first preset pressure range and the suction pressure of the compressor exceeds the first preset pressure range reaches a first preset time, which indicates that the surface of the evaporator frosts, at the moment, the evaporator needs to be defrosted, then, a water inlet of the gas cooler is controlled by the water path control valve and communicated with a hot water return pipe, a first throttling device is opened, the hot water return pipe guides hot water in the water tank into the gas cooler, therefore, the refrigerant discharged by the compressor can absorb the heat of the hot water when passing through the gas cooler, the temperature of the refrigerant is increased, the defrosting speed is increased, the defrosting time is shortened, and the user experience is better.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 shows CO provided by an embodiment of the present invention2The structure of the heat pump system is schematic;
FIG. 2 shows CO provided by an embodiment of the present invention2The heat pump system comprises a structural schematic diagram of a plurality of heating modules;
FIG. 3 is a flowchart of a control method of embodiment 1;
FIG. 4 is a flowchart of a control method of embodiment 2;
fig. 5 is a flowchart of a control method for adjusting the opening of the first throttle device according to the embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
As is well known, CO2Is a natural environment-friendly refrigerant which does not damage the atmospheric ozone layer and causes the whole climate to become warm, therefore, CO2Heat pump systems are ideal for heating water, but when operating at low outdoor temperatures and high humidity, CO is present2The evaporator surface on the air side in heat pump systems is prone to frost formation, resulting in CO2The heating capacity of the heat pump system is reduced.
Referring to fig. 1, the embodiment of the present invention provides CO2The heat pump system comprises a CO2Refrigerant circulation path and water supply circulation path, CO2The refrigerant circulation path includes a compressor 1, a gas cooler 3, a first throttle device 6, and an evaporator 7 connected end to end in this order. Wherein, the direction that the arrow indicates in fig. 1 is the flow direction of refrigerant, the water supply circulation path includes water tank 11 and water route connecting pipe subassembly, water inlet 12 and return water mouth 13 have been seted up on the water tank 11, water route connecting pipe subassembly includes supplying cold water pipe 14, hot water return pipe 15, water route control valve 32 and supplying hot water pipe 16, water inlet 12 and the hot water supply pipe 16 of water tank 11 communicate, return water mouth 13 and the hot water return pipe 15 of water tank 11 communicate, the water inlet 17 of gas cooler, supply cold water pipe 14, hot water return pipe 15 all are connected with water route control valve 32, the hot water supply pipe 16 communicates with the delivery port 18 of gas cooler, water route control valve 32 is used for controlling the water inlet 17 of gas cooler 3 and supplies cold water pipe 14 to communicate or break off, and control the water inlet 17 of gas cooler 3 and hot water return pipe 15 to communicate or break off.
The embodiment of the utility model provides a CO2When the heat pump system is used for heating water in the water tank 11, the water path control valve 32 controls the water inlet 17 of the gas cooler 3 to be communicated with the cold water supply pipe 14, cold water flows into the gas cooler 3, and at the moment, high-temperature and high-pressure refrigerant (namely CO) discharged by the compressor 12Refrigerant) can transfer heat to cold water flowing in from a water inlet 17 of the gas cooler 3 when passing through the gas cooler 3, the water is heated, the heated water flows into the water tank 11 through a water outlet 18 of the gas cooler 3, meanwhile, the refrigerant subjected to heat exchange in the gas cooler 3 enters the evaporator 7 through the first throttling device 6 to be evaporated and absorb heat, and finally returns to a suction port of the compressor 1, and a heating cycle is completed. When the above-mentioned CO is present2When the heat pump system is used for defrosting, the water inlet 17 and the hot water return pipe 15 intercommunication of the gas cooler 3 of water route control valve 32 control, first throttling arrangement 6 is opened, hot water return pipe 15 is in leading-in gas cooler 3 of hot water in with water tank 11, make compressor 1 exhaust refrigerant when passing through gas cooler 3, can absorb the heat of hot water, thereby improve the temperature that gets into refrigerant in the evaporimeter, accelerate defrosting speed, and shorten defrosting time, user experience is better.
Optionally, the embodiment of the present invention provides CO2Heat pumpThe system further comprises a gas-liquid separator 8, the gas-liquid separator 8 is connected to a connecting pipeline between the evaporator 7 and the compressor 1, a gas inlet of the gas-liquid separator 8 is communicated with an outlet of the evaporator 7, and a gas outlet of the gas-liquid separator 8 is communicated with a gas suction port of the compressor 1. In CO2In the operation process of the heat pump system, the gas-liquid separator 8 can not only perform the gas-liquid separation function on the refrigerant in a gas-liquid two-phase state discharged by the evaporator 7 to prevent the compressor 1 from sucking gas and carrying liquid, but also directly return to the air suction port of the compressor 1 compared with the refrigerant discharged by the evaporator 7, and the gas-liquid separator 8 is arranged to buffer the pressure of the refrigerant, so that the stable suction pressure and the safe and reliable operation of the compressor 1 are ensured. The cold water supply pipe 14 can be connected with municipal water, and can also be connected with water in the water tank 10.
Further, the above CO2The refrigerant circulation path further includes a first control valve 9, the first control valve 9 is connected in parallel to both ends of the first throttle device 6, and the refrigerant from the gas cooler 3 can directly pass through the first control valve 9 to enter the evaporator 7. The pressure loss of the refrigerant from the gas cooler 3 into the evaporator 7 by the first control valve 9 is smaller than the pressure loss of the refrigerant from the gas cooler 3 into the evaporator 7 by the first throttle device 6, i.e. the temperature of the refrigerant introduced into the inlet of the evaporator 7 by the first control valve 9 is higher, CO2The defrosting speed of the heat pump system is high, and the defrosting time is short. CO as described above2The refrigerant circulation path further includes a bypass line 19, and the first control valve 9 is disposed on the bypass line 19 such that an inlet of the first control valve 9 communicates with the refrigerant outlet 20 of the gas cooler 3, and an outlet of the first control valve 9 communicates with the intake port of the evaporator 7.
Alternatively, the above CO2The refrigerant circulation path also comprises a heat recovery branch 22 connected in parallel at two ends of the first throttling device 6, the heat recovery branch 22 is used for exchanging heat with a connecting pipeline at the exhaust port of the compressor 1, so that the refrigerant can absorb the heat of the refrigerant at the exhaust port of the compressor 1 in the heat recovery branch 22, the temperature of the refrigerant at the air inlet of the evaporator 7 is further increased, and the temperature of the refrigerant at the air inlet of the CO is further increased2Defrosting speed of heat pump system is shortenedCO is2Defrost time of the heat pump system.
The heat recovery branch 22 includes a heat recovery unit 2 and a second control valve 10 connected in series, the heat recovery unit 2 includes a heat exchange pipe wound around a connection pipe between an exhaust port of the compressor 1 and a refrigerant inlet 21 of the gas cooler 3, and the second control valve 10 is used to control the on/off of the heat recovery branch 22. Alternatively, the heat recovery branch 22 comprises a heat recoverer 2 and a second control valve 10 connected in series, the heat recoverer 2 comprises a heat exchange pipe wound between the refrigerant outlet 20 of the gas cooler 3 and the first throttling device 6, and the second control valve 10 is used for controlling the conduction or the disconnection of the heat recovery branch 22. Because the refrigerant can reduce through gas cooler 3 back temperature, the heat that the heat exchange tube can absorb is less, consequently, the embodiment of the utility model provides an on the heat exchange tube was around the connecting tube of establishing between compressor 1's gas vent and gas cooler 3's refrigerant import 21, the heat of compressor 1's gas vent department can be absorbed to the heat exchange tube to further improve the temperature that gets into refrigerant in the evaporimeter 7, shortened CO2Defrost time of the heat pump system.
Further, the above CO2The refrigerant circulation path further includes a regenerator 5, and a first heat exchange flow path in the regenerator 5 is connected in series between the outlet of the evaporator 7 and the suction port of the compressor 1, and a second heat exchange flow path in the regenerator is connected in series between the refrigerant outlet 20 of the gas cooler 3 and the inlet of the first throttling means 6. CO as described above2In the defrosting process of the heat pump system, the temperature of the refrigerant led out after condensation and heat release through the evaporator 7 is lower, namely, the temperature of the refrigerant of the second heat exchange flow path in the heat regenerator 5 is higher than that of the refrigerant of the first heat exchange flow path in the heat regenerator 5, so that the refrigerant can absorb the heat of the second heat exchange flow path in the heat regenerator 5 when passing through the first heat exchange flow path in the heat regenerator 5, the refrigerant flowing out of the first heat exchange flow path in the heat regenerator 5 is ensured to have proper superheat degree, the phenomenon that the compressor 1 absorbs air and carries liquid is avoided, and the safety and reliability in operation of the compressor 1 are ensured. Optionally, the regenerator 5 is connected in parallel with the first control valve 9, and the flow of the refrigerant passing through the regenerator 5 can be adjusted by the first control valve 9 (and/or the first throttling device 6) to ensure CO2The heat pump system operates stably.
Alternatively, the above CO2The refrigerant circulation passage further comprises an air supplementing assembly, the air supplementing assembly is communicated with an air supplementing port of the compressor 1, and the air supplementing assembly can supplement air to the compressor 1, so that the air displacement of the compressor 1 is increased, and the air exhaust temperature of the compressor 1 is reduced.
Further, the air supply assembly comprises an economizer 4 and an air supply branch 23 communicated with an air suction port of the compressor 1, a first heat exchange flow path in the economizer 4 is connected in series to the air supply branch 23, a second heat exchange flow path in the economizer 4 is connected in series between a refrigerant outlet 20 of the gas cooler 3 and an inlet of the first throttling device 6, the air supply branch 23 comprises a second throttling device 41 and a third control valve 42 which are connected in series, the second throttling device 41 is located on one side of the inlet of the first heat exchange flow path in the economizer 4, and the third control valve 42 is used for controlling connection or disconnection of the air supply branch 23. Optionally, economizer 4 among the above-mentioned tonifying qi subassembly also can be replaced by the flash tank, but consider that the steam pressure of refrigerant is not good to be controlled in the flash tank, need all set up electronic expansion valve at the front end and the rear end of flash tank, lead to tonifying qi subassembly structure complicacy, and the cost is higher, so, the embodiment of the utility model provides an in adopt the former scheme. Specifically, the third controller 42 is installed at the outlet side of the first heat exchange flow path in the economizer 4.
Alternatively, the inlet of the second throttle device 41 may be connected to the connecting pipe between the gas cooler 3 and the economizer 4; alternatively, the inlet of the second throttle device 41 can also be connected to the connecting line between the economizer 4 and the first throttle device 6. Compared with the former, the latter scheme is more suitable for the temperature of the refrigerant introduced into the second throttling device 41, and can better balance the advantages and disadvantages of air make-up and enthalpy increase, therefore, the latter scheme is adopted in the embodiment of the utility model.
It should be noted that: for CO2In the heat pump system including both the economizer 4 and the regenerator 5, the economizer 4 may be disposed on a connection pipe between the regenerator 5 and the gas cooler 3, or on a connection pipe between the regenerator 5 and the first throttling device 6. Taking into account refrigerant passing backThe temperature drop after the heat exchanger 5 is more than that of the refrigerant passing through the economizer 4, and the former can better prevent CO2The heat pump system is supplied with air and liquid, and the running reliability of the compressor 1 is ensured. In addition, the import of above-mentioned second throttling arrangement 41 can be installed on the connecting tube between economizer 4 and regenerator 5, also can install on the connecting tube between regenerator 5 and the import of first throttling arrangement 6, and the same reason, the embodiment of the utility model provides an adopt the scheme of the former.
Based on the above embodiment, the economizer 4 is connected in parallel with the first control valve 9, and the flow rate of the refrigerant entering the economizer 4 can be adjusted by opening and closing the first control valve 9. The first control valve 9, the second control valve 10, and the third control valve 42 may be selected from solenoid valves or electronic expansion valves.
Further, the valve caliber of the first control valve 9 is larger than the valve caliber when the first throttling device 6 is fully opened, so that the flowing resistance of the refrigerant when the first control valve 9 is fully opened is smaller than the flowing resistance of the refrigerant passing through the first throttling device 6, when the first control valve 9 is opened, most of the high-temperature refrigerant directly enters the evaporator 7 through the first control valve 9, the evaporator 7 is defrosted, and the defrosting effect is good.
If the valve caliber of the second control valve 10 is larger than the valve caliber of the first throttling device 6 when the first throttling device is fully opened, most of the refrigerant absorbs the heat at the air outlet of the compressor 1 through the heat recoverer 2, so that the temperature of the refrigerant at the air outlet of the compressor 1 is reduced more, and if the reduced temperature of the refrigerant cannot be compensated in time when the refrigerant passes through the gas cooler 3, the temperature of the refrigerant entering the evaporator 7 is low, and the defrosting effect is poor. Therefore, the valve caliber of the second control valve 10 in the embodiment of the present invention is smaller than the valve caliber when the first throttling device 6 is fully opened.
For CO2The scheme that the heat pump system comprises a first throttling device 6, a first control valve 9 and a second control valve 10 is adopted, when the first throttling device 6, the first control valve 9 and the second control valve 10 are all opened, most of high-temperature refrigerant can be guaranteed to directly enter an evaporator 7 through the first control valve 9, only a small part of refrigerant enters a heat recovery device 2 for heat recovery after being throttled by the second control valve 10, and each branch is internally provided with a branchIs appropriate so that CO is2The defrosting effect of the heat pump system is better.
CO as described above2The heat pump system comprises a plurality of heating modules, and each heating module consists of a CO2The refrigerant circulation passage and the water supply circulation passage are formed, and the water heater is suitable for the condition that a large amount of water needs to be heated; of course, CO2The heat pump system may also comprise only one heating module as described above, as illustrated in fig. 1. CO in FIG. 22The heat pump system includes a first heating module 100, a second heating module 200, and a third heating module 300, and water supply circulation paths of the three heating modules are communicated with the same water tank 11. For CO in this case2The number of heating modules in the heat pump system is not particularly limited.
The embodiment of the utility model provides a still provide one and be used for above-mentioned CO2The defrosting control method of the heat pump system comprises the following steps:
when CO is detected2When the heat pump system reaches a first defrosting condition, a first throttling device is opened, a water channel control valve controls a water inlet of a gas cooler to be communicated with a hot water return pipe, the first defrosting condition at least comprises that the suction pressure of a compressor exceeds a first preset pressure range, and the duration time that the suction pressure of the compressor exceeds the first preset pressure range reaches a first preset time.
CO as described above2The heat pump system comprises a controller, the controller detects and obtains the suction pressure of the compressor from a suction pressure sensor arranged at a suction port of the compressor, and the controller further comprises a timing module, and the timing module is used for recording the duration that the suction pressure of the compressor exceeds a first preset pressure range. The operations of opening the first throttling device and controlling the communication between the water inlet of the gas cooler and the hot water return pipe by the waterway control valve are all executed by the controller. When the controller judges that the obtained suction pressure exceeds a first preset pressure range and the timing module records that the duration time reaches first preset time, the controller controls the first throttling device to be opened and controls the water path control valve to communicate the water inlet of the gas cooler with the hot water return pipe, and when refrigerant discharged by the compressor passes through the gas cooler, the refrigerant can absorb hot water heatAmount of refrigerant, CO2The defrosting speed of the heat pump system is increased, the defrosting time is shortened, and the user experience is better.
It should be noted that: the first defrosting condition further comprises CO2Ambient temperature T of heat pump systemaExceeds a first preset ambient temperature range and the evaporator liquid pipe temperature TeOut of a first predetermined range of liquid tube temperatures, or CO2Ambient temperature T of heat pump systemaOut of a second predetermined ambient temperature range and evaporator liquid tube temperature TeOut of ambient temperature TaTemperature difference range from the first preset temperature value, CO2The heat pump system may satisfy any one of the above-described three first defrosting conditions.
Further, the defrosting control method further includes:
when CO is detected2When the heat pump system reaches a defrosting ending condition, the water path control valve controls the water inlet of the gas cooler to be disconnected with the hot water return pipe, and the defrosting ending condition comprises that the temperature of a main air pipe of the evaporator exceeds a first preset main air pipe temperature range. The controller acquires the temperature of the main air pipe from an air pipe temperature sensor arranged at the main air pipe of the evaporator, when the temperature of the main air pipe is greater than or equal to a first preset temperature of the main air pipe, the controller sends a control signal to the water path control valve, and after the water path control valve receives the control signal, the water inlet of the gas cooler is controlled to be disconnected from the hot water return pipe, and defrosting is finished.
Further, the above CO2The heat pump system also comprises a first control valve which is connected in parallel at two ends of the first throttling device. CO as described above2The defrosting control method of the heat pump system further includes:
when CO is detected2And when the heat pump system reaches a first defrosting condition, opening the first control valve. The controller controls the first control valve to be opened, and most of the refrigerant enters the evaporator through the first control valve, so that the amount of the refrigerant entering the evaporator is large, and the defrosting effect is good. Optionally, the defrosting control method further includes: when CO is detected2When the heat pump system reaches a first defrosting end condition, controlling a first control valve to closeAnd (5) closing. Of course, the closing operation of the first control valve is also controlled by the controller.
Based on the above example, CO2The defrosting control method of the heat pump system further includes:
when CO is detected2And when the heat pump system reaches a second defrosting condition, opening the first control valve and closing the first throttling device, wherein the waterway control valve controls the water inlet of the gas cooler to be disconnected with the hot water return pipe, the second defrosting condition at least comprises that the suction pressure of the compressor exceeds a second preset pressure range, and the duration of the suction pressure of the compressor exceeding the second preset pressure range reaches a second preset time.
It should be noted that: the second defrosting condition further comprises CO2The ambient temperature Ta of the heat pump system exceeds a third preset ambient temperature range and the temperature T of the liquid pipe of the evaporatoreOut of a third predetermined range of liquid tube temperatures, or CO2Ambient temperature T of heat pump systemaOut of the fourth preset ambient temperature range and evaporator liquid tube temperature TeOut of ambient temperature TaTemperature difference range from second preset temperature value, CO2The heat pump system may satisfy any one of the above-described three second defrosting conditions.
Similarly, the operations of opening the first control valve, closing the first throttling device and controlling the disconnection of the water inlet of the gas cooler and the hot water return pipe by the waterway control valve are controlled and executed by the controller, and the method is suitable for the condition that the surface frost layer of the evaporator is thin.
Further, the above CO2CO in heat pump system2The refrigerant circulating passage also comprises heat recovery branches connected in parallel at two ends of the first throttling device, each heat recovery branch comprises a heat recoverer and a second control valve which are connected in series, each heat recoverer comprises a heat exchange tube, the heat exchange tubes are wound on a connecting pipeline between an exhaust port of the compressor and the gas cooler, and the second control valves are used for controlling the connection or disconnection of the heat recovery branches; CO as described above2The defrosting control method of the heat pump system further includes: when CO is detected2And when the heat pump system reaches the first defrosting condition, opening the second control valve. The controller controls the second control valveOpening the heat exchanger to enable part of refrigerant to absorb heat at the exhaust port of the compressor, increasing the temperature of the refrigerant in the heat recovery branch, and further increasing the temperature of the refrigerant entering the evaporator, thereby further increasing the CO2The defrosting speed of the heat pump system shortens the defrosting time. Optionally, the defrosting control method further includes: when CO is detected2And when the heat pump system reaches the first defrosting end condition, controlling the second control valve to close. Of course, the closing operation of the second control valve is also controlled by the controller.
CO as described above2The heat pump system comprises a plurality of heating modules, and each heating module consists of a CO2A refrigerant circulation path and a water supply circulation path; CO as described above2The defrosting control method of the heat pump system specifically comprises the following steps: if the total number of the heating modules needing defrosting is less than or equal to the maximum defrosting number, controlling the first throttling devices included in all the heating modules needing defrosting to be opened, and controlling the water paths included in the water supply circulation passages needing defrosting to control the water inlets of the gas coolers to be communicated with the hot water return pipe; and if the total number of the heating modules needing defrosting is larger than the maximum defrosting number, after at least one heating module finishes defrosting, controlling a first throttling device included in the heating module to be defrosted to be opened, and controlling a water path control valve corresponding to a water supply circulation passage to be defrosted to control the water inlet of the gas cooler to be communicated with a hot water return pipe. The controller performs the above operation according to the CO2The specific design parameters of the heat pump system control the number of heating modules for defrosting simultaneously, so that the fluctuation of the water temperature in the water tank is small under the condition of ensuring the defrosting speed.
It should be noted that: the maximum defrosting number N is calculated by the formula: n is calculated as 5L × M/Q, where the total capacity of the heat pump is Q (in units of pieces), M (in units of pieces) is the total number of heating modules, and L (in units of M) is the total number of heating modules3) Is the volume of the water tank.
When the host computer receives a defrosting request signal of a heating module needing defrosting, the number of the heating modules which are defrosting is added by 1, and then the relation between the number of the heating modules which are defrosting and the maximum defrosting number is judged. Optionally, if the total number M of the heating modules to be defrosted is less than or equal to 5 lxm/Q, it indicates that defrosting the heating modules to be defrosted does not cause a decrease in water temperature in the water tank, and then the host sends a defrosting permission signal to the heating modules to be defrosted. If the total number M of the heating modules needing defrosting is larger than 5L multiplied by M/Q, the fact that the water temperature in the water tank is reduced when the heating modules to be defrosted are defrosted is shown, at the moment, the host computer sends a defrosting waiting signal to the heating modules to be defrosted, and after at least one heating module finishes defrosting, the controller controls the heating modules to be defrosted to send defrosting permission signals.
Further, the above-mentioned first throttling device is an electronic expansion valve, and the opening of the first throttling device specifically includes: opening the first throttling device at a preset opening degree; the opening degree of the first throttling device is adjusted according to the suction superheat degree of the compressor. An air suction temperature sensor and an air suction pressure sensor are installed at an air suction port of the compressor, and an air suction superheat degree T is calculated and obtained by a controller according to an air suction temperature value detected by the air suction temperature sensor and an air suction pressure value detected by the air suction pressure sensorso(ii) a Specifically, the suction superheat degree TsoThe difference value is obtained by subtracting the saturation temperature of the refrigerant corresponding to the suction pressure value from the suction temperature of the compressor.
The adjusting the opening degree of the first throttling device specifically comprises:
and when the suction superheat degree of the compressor is greater than the preset suction superheat degree, reducing the opening degree of the first throttling device. The fact that the suction superheat degree of the compressor is larger than the preset suction superheat degree indicates that CO is in the process2The majority of the refrigerant in the heat pump system passes through the first throttling device, so that only a small part of the refrigerant passes through the first control valve, and the opening degree of the first throttling device is reduced, so that the refrigerant flow passing through the first control valve is increased, and at the moment, CO (carbon monoxide) is generated2The defrosting speed of the heat pump system is high.
And when the suction superheat degree of the compressor is less than the preset suction superheat degree, increasing the opening degree of the first throttling device. The fact that the suction superheat of the compressor is less than the preset suction superheat indicates CO2The heat pump system is easy to absorb air and carry liquid, and the pressure can be increased by increasing the opening degree of the first throttling deviceThe suction superheat of the compressor.
And when the suction superheat degree of the compressor is equal to the preset suction superheat degree, maintaining the current opening degree of the first throttling device. The suction superheat of the compressor is equal to the preset suction superheat indicating CO2The defrosting speed of the heat pump system is high, the phenomenon of air suction and liquid carrying is avoided, and the current opening degree of the first throttling device is kept.
Alternatively, the increasing the opening degree of the first throttle device may be increasing the opening degree of the first throttle device to a set opening degree, or increasing the opening degree of the first throttle device to a preset opening degree based on the current opening degree of the first throttle device. Similarly, the reduction in the opening degree of the first throttle device may be calculated in a similar manner.
Further, the water supply circulation path may further include a water supply pump for introducing or discharging water to or from the gas cooler. CO as described above2The defrosting control method of the heat pump system further includes:
when CO is detected2When the heat pump system reaches a first defrosting condition, the water supply pump is turned on; when CO is detected2And when the heat pump system reaches the second defrosting condition, the water supply pump is closed. The controller controls the water supply pump to be turned on and off when the CO is detected2When the heat pump system reaches a first defrosting condition, the water supply pump guides hot water in the water tank into the gas cooler through the hot water return pipe, so that the heat exchange efficiency of the hot water and a refrigerant in the gas cooler is improved; when CO is detected2When the heat pump system reaches the second defrosting condition, the water supply pump stops introducing the hot water in the water tank into the gas cooler through the hot water return pipe.
Based on the above embodiment, the turning on the water supply pump specifically includes: turning on the water supply pump at a preset rotation speed; and adjusting the rotation speed of the water supply pump according to the exhaust temperature value of the compressor and the outlet temperature value of the gas cooler. According to the difference of the exhaust temperature value of the compressor and the outlet temperature value of the gas cooler in different working conditions, the water supply pump is adjusted to operate at a proper rotating speed, and the heat exchange efficiency of hot water and the refrigerant in the gas cooler is controlled, so that the temperature of the refrigerant outlet of the gas cooler is controlled.
It should be noted that: the rotating speed of the water supply pump is inversely proportional to a voltage duty ratio signal for controlling the rotating speed of the water supply pump, and the rotating speed of the water supply pump is adjusted by adjusting the magnitude of the voltage duty ratio signal. Specifically, the target water supply pump voltage duty signal PWM (n) ═ PWM (n-1) + Δ PWM, where PWM (n-1) is the last voltage duty signal and Δ PWM is a water supply pump voltage duty signal correction value according to the discharge temperature of the compressor and the refrigerant temperature at the outlet of the gas cooler. The water supply pump voltage duty signal correction value Δ PWM may be obtained by a table lookup, for example, as shown in table 1:
TABLE 1 water supply pump voltage duty ratio signal correction value Delta PWM parameter table
The following description of the embodiment CO of the present invention is made in conjunction with two specific embodiments2The defrosting control method of the heat pump system is further described.
Example 1
FIG. 3 is CO2The first defrosting condition is the suction pressure P of the compressorSNot more than 1.9Mpa, and the suction pressure P of the compressorSThe duration t is less than or equal to 1.9Mpa1The time is more than or equal to 1min, namely the first preset pressure range is that the suction pressure is more than 1.9Mpa, and the first preset time is 1 min; or the first defrosting condition is an ambient temperature TaNot less than 6 ℃ and the liquid tube temperature T of the evaporatoreNot more than-4 ℃, namely the first preset environmental temperature range is the environmental temperature TaThe temperature of the first preset liquid pipe is less than 6 ℃, and the temperature range of the evaporator liquid pipe is that the temperature of the evaporator liquid pipe is greater than-4 ℃; or the first defrosting condition is T being more than 5 ℃ below zeroa< 6 ℃ and evaporator liquid tube temperature Te≤Ta10 ℃ below zero, i.e. the second predetermined ambient temperature range is the ambient temperature TaLess than or equal to-5 ℃ or the ambient temperature TaGreater than or equal to 6 ℃, and the temperature range of the liquid pipe of the evaporator is greater than the ambient temperature TaThe temperature difference is 10 ℃ from the first preset temperature value;or the first defrosting condition is an ambient temperature TaAt a temperature of-5 ℃ or lower and the temperature T of the liquid pipe of the evaporatore≤Ta-9 ℃, i.e. the second predetermined ambient temperature range is the ambient temperature TaMore than-5 deg.C, the liquid tube temperature of the evaporator being greater than ambient temperature TaThe temperature difference with the first preset temperature value is 9 ℃. The first defrosting end condition is the temperature T of the main air pipe of the evaporatorg1The temperature of the first preset main air pipe is more than or equal to 8 ℃, namely the temperature range of the first preset main air pipe is that the temperature of the main air pipe is less than 8 ℃.
CO2The specific defrosting process of the heat pump system comprises the following steps: when the value of the suction pressure PS1Not more than 1.9MPa, and t1Not less than 1min, or TaNot less than 6 ℃ and TeLess than or equal to-4 ℃; or < T at-5 ℃a< 6 ℃ and Te≤Ta-10 ℃; or TaAt a temperature of-5 ℃ or lower and Te≤TaAnd at the temperature of-9 ℃, the controller controls the water supply pump to be opened, the first throttling device to be opened, the first control valve to be opened and the second control valve to be opened. When T isg1At a temperature of not less than 8 ℃ CO2The heat pump system reaches a first defrost termination condition.
In CO2During defrosting of the heat pump system, the controller adjusts the rotating speed of the water supply pump according to specific logic and controls the first throttling device to calculate the opening degree according to the specific logic. The rotation speed adjustment of the water supply pump and the calculation of the opening degree of the first throttle device have been described previously and will not be described in detail.
Example 2
FIG. 4 shows CO2The second defrosting condition is the suction pressure P of the compressorSNot more than 2.2Mpa, and the suction pressure P of the compressorSThe duration t is less than or equal to 2.2Mpa2The second preset pressure range is that the suction pressure is more than 2.2Mpa, and the second preset time is 1 min; or the second defrosting condition is an ambient temperature TaNot less than 6 ℃ and the liquid tube temperature T of the evaporatoreNot more than-2 ℃, namely the third preset environmental temperature range is the environmental temperature TaThe temperature of the third preset liquid pipe is less than 6 ℃, and the temperature range of the evaporator liquid pipe is more than-2 ℃; or the second defrostingUnder the condition that T is less than-5 DEG Ca< 6 ℃ and evaporator liquid tube temperature TaTa-8 ℃ or below, namely the fourth preset environmental temperature range is the environmental temperature TaLess than or equal to-5 ℃ or the ambient temperature TaGreater than or equal to 6 ℃, and the temperature range of the liquid pipe of the evaporator is greater than the ambient temperature TaThe temperature difference is 8 ℃ from the second preset temperature value; or the second defrosting condition is an ambient temperature TaAt a temperature of-5 ℃ or lower and the temperature T of the liquid pipe of the evaporatore≤Ta-7 ℃, i.e. the fourth predetermined ambient temperature range is the ambient temperature TaMore than-5 deg.C, the liquid tube temperature of the evaporator being greater than ambient temperature TaAnd the temperature difference is 7 ℃ with the second preset temperature value. The second defrosting end condition is the temperature T of the main air pipe of the evaporatorg2Not less than 5 ℃ or defrosting time t3And more than or equal to 9min, namely the temperature range of the second preset main air pipe is that the temperature of the main air pipe is less than 5 ℃, and the third preset time is 9 min.
CO2The specific defrosting process of the heat pump system comprises the following steps: when the value of the suction pressure PsNot more than 2.2MPa, and t2Not less than 1min, or TaNot less than 6 ℃ and TeLess than or equal to-2 ℃; or < T at-5 ℃a< 6 ℃ and Te≤Ta-8 ℃; or TaAt most-5 ℃ and Te≤Ta-7 ℃, the controller controls the feed water pump to be closed, the first throttling means to be closed and the first control valve to be opened. When T isg2Not less than 5 ℃ or t3CO for more than or equal to 9min2The heat pump system reaches a second defrost termination condition.
FIG. 5 shows the CO of the present invention2In an embodiment of the opening degree adjustment of the first throttle device in the heat pump system, the preset suction superheat degree of the compressor is 1 ℃, and the preset opening degree of the first throttle device is 2% EVOmax，EVOmaxAssuming a maximum opening EVO of the first throttle device as a maximum opening of the first throttle devicemaxIs 500pls (pulse), and the preset opening is 10 pls. When the suction superheat degree of the compressor is more than 1 ℃, reducing the opening degree EVO (i) of the target first throttling device by 2% on the basis of the current opening degree EVO (i-1) of the first throttling device; when the suction superheat of the compressor is equal to 1 deg.C, the target is firstOpening degree EVO (i) of the throttling device keeps the opening degree EVO (i-1) of the current first throttling device unchanged; when the suction superheat of the compressor is less than 1 ℃, the opening degree EVO (i) of the target first throttling device is increased by 2% of the preset opening degree based on the current opening degree EVO (i-1) of the first throttling device. After the above operation is performed, when the opening degree evo (i) of the holding target first throttle reaches the control period t, the process returns to the start of the judgment again, and the next cycle is entered. Wherein the control period t ranges from 10s to 90 s. Illustratively, the control period t in fig. 5 is 50 s.
In the description herein, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (11)
1. CO (carbon monoxide)2Heat pump system, characterized in that it comprises CO2A refrigerant circulation path and a water supply circulation path, the CO2The refrigerant circulation path comprises a compressor, a gas cooler, a first throttling device and an evaporator which are sequentially connected end to end, the water supply circulation path comprises a water tank and a water path connecting pipe assembly, a water inlet and a water return port are formed in the water tank, the water path connecting pipe assembly comprises a cold water supply pipe, a hot water return pipe, a water path control valve and a hot water supply pipe, the water inlet of the water tank is communicated with the hot water supply pipe, the water return port of the water tank is communicated with the hot water return pipe, the water inlet of the gas cooler is connected with the cold water supply pipe, the hot water return pipe is connected with the water path control valve, the hot water supply pipe is communicated with the water outlet of the gas cooler, and the water path control valve is used for controlling the water inlet of the gas cooler and the cold water supply pipe toSwitching on or off, and controlling the water inlet of the gas cooler to be communicated or disconnected with the hot water return pipe.
2. CO according to claim 12Heat pump system, characterized in that the CO2The refrigerant circulation path further includes a first control valve connected in parallel across the first throttle device.
3. CO according to claim 12Heat pump system, characterized in that the CO2The refrigerant circulating path also comprises heat recovery branches connected in parallel at two ends of the first throttling device, and the heat recovery branches are used for exchanging heat with a connecting pipeline at the air outlet of the compressor.
4. CO according to claim 32The heat pump system is characterized in that the heat recovery branch comprises a heat recoverer and a second control valve which are connected in series, the heat recoverer comprises a heat exchange tube, the heat exchange tube is wound on a connecting pipeline between an exhaust port of the compressor and the gas cooler, and the second control valve is used for controlling the conduction or the disconnection of the heat recovery branch.
5. CO according to claim 12Heat pump system, characterized in that the CO2The refrigerant circulation path further comprises a heat regenerator, a first heat exchange flow path in the heat regenerator is connected between the outlet of the evaporator and the suction port of the compressor in series, and a second heat exchange flow path in the heat regenerator is connected between the refrigerant outlet of the gas cooler and the inlet of the first throttling device in series.
6. CO according to claim 1 or 52Heat pump system, characterized in that the CO2The refrigerant circulation passage further comprises an air supplement component which is communicated with an air supplement port of the compressor.
7. CO according to claim 62The heat pump system is characterized in that the air supplement component comprises an economizer and an air supplement branch communicated with an air suction port of the compressor, a first heat exchange flow path in the economizer is connected in series on the air supplement branch, a second heat exchange flow path in the economizer is connected in series between a refrigerant outlet of the gas cooler and an inlet of the first throttling device, the air supplement branch comprises a second throttling device and a third control valve which are connected in series, the second throttling device is located on one side of the inlet of the first heat exchange flow path in the economizer, and the third control valve is used for controlling connection or disconnection of the air supplement branch.
8. CO according to claim 22The heat pump system is characterized in that the valve caliber of the first control valve is larger than that of the first throttling device when the first throttling device is fully opened.
9. CO according to claim 42The heat pump system is characterized in that the valve caliber of the second control valve is smaller than that of the first throttling device when the first throttling device is fully opened.
10. CO according to claim 72A heat pump system characterized in that an inlet of the second throttle device is connected to a connection pipe between the economizer and the first throttle device.
11. CO according to claim 12A heat pump system comprising a plurality of heating modules, each heating module being comprised of one of said COs2A refrigerant circulation path and one of the water supply circulation paths.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921219917.5U CN210399609U (en) | 2019-07-30 | 2019-07-30 | CO2 heat pump system |
| PCT/CN2020/111548 WO2021018314A1 (en) | 2019-07-30 | 2020-08-27 | Co2 heat pump system and defrosting control method therefor |
| US17/562,376 US20230132393A9 (en) | 2019-07-30 | 2021-12-27 | Air source heat pump system and defrosting control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201921219917.5U CN210399609U (en) | 2019-07-30 | 2019-07-30 | CO2 heat pump system |
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| CN210399609U true CN210399609U (en) | 2020-04-24 |
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| CN201921219917.5U Active CN210399609U (en) | 2019-07-30 | 2019-07-30 | CO2 heat pump system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021018314A1 (en) * | 2019-07-30 | 2021-02-04 | 青岛海信日立空调***有限公司 | Co2 heat pump system and defrosting control method therefor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021018314A1 (en) * | 2019-07-30 | 2021-02-04 | 青岛海信日立空调***有限公司 | Co2 heat pump system and defrosting control method therefor |
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