阅读说明：本技术 低温空气源热泵系统的模块控制方法 (Module control method of low-temperature air source heat pump system ) 是由 赵密升 刘振乐 李建国 张远忠 徐子超 赵林 苏昀 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种低温空气源热泵系统的模块控制方法,属于低温空气源热泵技术领域,为解决现有机组频繁启停导致压缩机故障等问题而设计。本发明低温空气源热泵系统的模块控制方法,在加载阶段、保持阶段、卸载阶段以及急停阶段中,低温空气源热泵机组的启动和加载各自独立控制,启动回差Tdt的数值与加载回差Tld的数值不关联,至少在加载阶段中对加载回差Tld进行修正。本发明低温空气源热泵系统的模块控制方法能减少机组全部能级的启停次数,使机组更加高效地运行并提升机组的使用寿命,提升机组的运行稳定性及可靠性,压缩机更加节能高效；能扩大加载阶段的范围,从而使机组控制更稳定。(The invention discloses a module control method of a low-temperature air source heat pump system, belongs to the technical field of low-temperature air source heat pumps, and is designed for solving the problems of compressor failure and the like caused by frequent start and stop of the conventional unit. According to the module control method of the low-temperature air source heat pump system, the starting and the loading of the low-temperature air source heat pump unit are independently controlled in the loading stage, the maintaining stage, the unloading stage and the emergency stop stage, the value of the starting return difference Tdt is not related to the value of the loading return difference Tld, and the loading return difference Tld is corrected at least in the loading stage. The module control method of the low-temperature air source heat pump system can reduce the starting and stopping times of all energy levels of the unit, enables the unit to run more efficiently, prolongs the service life of the unit, improves the running stability and reliability of the unit, and enables the compressor to be more energy-saving and efficient; the range of the loading stage can be enlarged, so that the unit control is more stable.)

1. A module control method of a low-temperature air source heat pump system is characterized in that in a loading stage, a maintaining stage, an unloading stage and an emergency stop stage, the starting and the loading of the low-temperature air source heat pump unit are controlled independently, the value of a starting return difference Tdt is not related to the value of a loading return difference Tld, and the loading return difference Tld is corrected at least in the loading stage.

2. The module control method of the low-temperature air source heat pump system according to claim 1, wherein timing is started after the low-temperature air source heat pump system loads an energy level, when a timing duration when the instruction for entering the unloading stage is received is less than a first set Time Tzf, the loading return difference Tld is corrected, the corrected loading return difference Tld2 is (Tzf +1) × Tld/Time1, wherein the Time1 is an actual running duration after timing.

3. The module control method of a cryogenic air source heat pump system according to claim 2, characterized in that the first set time Tzf e [18 min, 22 min ].

4. The method for controlling the module of the low-temperature air source heat pump system according to claim 2, further comprising a second set time Tzs, Tzs > Tzf, wherein the loading return difference Tld is not corrected when the time after the low-temperature air source heat pump system is loaded with an energy level exceeds the second set time Tzs.

5. The module control method of a low-temperature air source heat pump system according to claim 4, wherein the second set time Tzs e [23 min, 27 min ].

6. The module control method of the low-temperature air source heat pump system according to any one of claims 1 to 5, wherein a system return water temperature Tin is obtained by measurement, a target temperature Tset and a heating return difference Tdt are set, and Δ T-Tin-Tset are set; when the delta T is larger than the Tdt, the low-temperature air source heat pump system is started, and the number Nneed of the compressors at the initial startup is delta T multiplied by Cmax/Tmax, wherein Cmax is the total number of the compressors in the low-temperature air source heat pump system, and Tmax is the difference value between the target temperature Tset and the return water temperature Tin when the compressors are required to be fully started.

7. The module control method of a cryogenic air source heat pump system according to claim 6, wherein the loading phase is entered when Δ T > Tld, and the holding phase is entered when Δ T ≦ Tld; tuld is unloading return difference, the unloading stage is entered when-Delta T is less than Tuld, and the emergency stop stage is entered when-Delta T is greater than or equal to Tuld.

8. The module control method of a low-temperature air source heat pump system according to claim 6, wherein when Tmax > Tdt, the ratio of the pre-start number of the compressors at initial start-up is Tdt/Tmax; when Tmax is less than Tdt, all the compressors are started at the initial startup.

9. The module control method of a cryogenic air source heat pump system according to claim 6, wherein when the module control method is in the loading phase, every other energy control period is loaded with one energy level until all energy is loaded;

maintaining a current energy level when the module control method is in the maintenance phase;

when the module control method is in the unloading stage, unloading an energy level every other energy control period until all the energy is unloaded;

and unloading one energy level every preset time when the module control method is in the emergency stop stage.

10. A low-temperature air source heat pump system, comprising an indoor unit (100) and at least two low-temperature air source heat pumps, wherein one of the at least two low-temperature air source heat pumps is used as a master (201), the other low-temperature air source heat pumps are used as slaves (202), a controller (300) is arranged on the master, the controller (300) is respectively connected to all the slaves (202) in a communication manner, and the low-temperature air source heat pump system executes the module control method of the low-temperature air source heat pump system according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of low-temperature air source heat pumps, in particular to a module control method of a low-temperature air source heat pump system and the low-temperature air source heat pump system for executing the module control method.

Background

Because the functions and the working principle are similar, the existing modular control of the low-temperature air source heat pump mainly adopts the control mode and the technical route of a normal-temperature air conditioner module machine.

However, the low-temperature air source heat pump mainly uses heating, the span of the use environment is large, and the change of the environmental temperature is so great as to influence the heating capacity of the unit; the conventional air-conditioning module machine mainly performs refrigeration, has small span of use environment, has the main influence of environment temperature change as the energy efficiency ratio of the machine set, and has small change of refrigeration capacity, so the existing modular control of the low-temperature air source heat pump has great defect.

Specifically, in the existing modular control of the low-temperature air source heat pump, the start return difference and the load return difference are the same parameter point, that is, the start return difference is the load return difference. When the parameter setting is large (for example, 5 ℃), the unit is set to be 45 ℃, one unit is started initially, the water temperature of the unit enters a holding area (for example, 41 ℃), the unit is not loaded any more, and the operation requirement of the unit does not reach the design requirement. When the set setting parameters of the unit are relatively small (for example, 2 ℃), the conditions that the unit needs to be unloaded after loading an energy level and needs to be loaded after unloading often occur, namely, a part of the unit is in a frequent start-stop state, so that liquid impact fault caused by liquid accumulation of the compressor is caused, the operation energy-saving effect of the unit is influenced, and the service life of the unit is prolonged; in addition, the short startup time of the unit can cause that the system circulation is not completely established, the compressor continuously runs with liquid, and the unit directly breaks down and cannot be started up when the compressor is accumulated to a certain degree.

Disclosure of Invention

The invention aims to provide a module control method of a low-temperature air source heat pump system, which is stable in operation and solves the problem that a unit is frequently started and stopped in the prior art.

Another object of the present invention is to provide a low-temperature air source heat pump system which operates smoothly.

To achieve the purpose, on one hand, the invention adopts the following technical scheme:

a module control method of a low-temperature air source heat pump system is characterized in that in a loading stage, a maintaining stage, an unloading stage and an emergency stop stage, the starting and the loading of the low-temperature air source heat pump unit are controlled independently, the value of a starting return difference Tdt is not related to the value of a loading return difference Tld, and the loading return difference Tld is corrected at least in the loading stage.

Particularly, the low-temperature air source heat pump system starts to Time after loading an energy level, when the Time duration when the unloading stage entering command is received is less than a first set Time Tzf, the load return difference Tld is corrected, and the corrected load return difference Tld2 is (Tzf +1) × Tld/Time1, wherein the Time1 is the actual running Time duration after the Time is counted.

In particular, the first set time Tzf ∈ [18 minutes, 22 minutes ].

In particular, the module control method further comprises a second set time Tzs, Tzs > Tzf, and when the time after the low-temperature air source heat pump system is loaded with one energy level exceeds the second set time Tzs, the loading return difference Tld is not corrected.

In particular, the second set time Tzs ∈ [23 minutes, 27 minutes ].

Particularly, the system backwater temperature Tin is obtained through measurement, a target temperature Tset and a heating return difference Tdt are set, and the delta T is made to be Tset-Tin and made to be-delta T-Tin; when the delta T is larger than the Tdt, the low-temperature air source heat pump system is started, and the number Nneed of the compressors at the initial startup is delta T multiplied by Cmax/Tmax, wherein Cmax is the total number of the compressors in the low-temperature air source heat pump system, and Tmax is the difference value between the target temperature Tset and the return water temperature Tin when the compressors are required to be fully started.

In particular, the loading phase is entered when Δ T > Tld and the holding phase is entered when Δ T ≦ Tld; tuld is unloading return difference, the unloading stage is entered when-Delta T is less than Tuld, and the emergency stop stage is entered when-Delta T is greater than or equal to Tuld.

Particularly, when Tmax is larger than Tdt, the pre-starting number proportion of the compressor at the initial starting is Tdt/Tmax; when Tmax is less than Tdt, all the compressors are started at the initial startup.

Particularly, when the module control method is in the loading stage, loading an energy level every other energy control period until all the energy is loaded; maintaining a current energy level when the module control method is in the maintenance phase; when the module control method is in the unloading stage, unloading an energy level every other energy control period until all the energy is unloaded; and unloading one energy level every preset time when the module control method is in the emergency stop stage.

On the other hand, the invention adopts the following technical scheme:

a low-temperature air source heat pump system comprises an indoor unit and at least two low-temperature air source heat pumps, wherein one of the at least two low-temperature air source heat pumps serves as a host, the other low-temperature air source heat pumps serve as slaves, a controller is arranged on the host, the controller is respectively in communication connection with all the slaves, and the low-temperature air source heat pump system executes the module control method of the low-temperature air source heat pump system.

According to the module control method of the low-temperature air source heat pump system, the starting and loading of the unit are respectively and independently controlled through the starting return difference and the loading return difference of the separation unit, the starting and stopping times of all energy levels of the unit can be reduced, the unit can run more efficiently, the service life of the unit is prolonged, the problem that the temperature difference between a keeping stage and a target temperature is too large is solved, the running stability and the reliability of the unit are improved, the compressor is more energy-saving and efficient, and the user experience is good; the range of the loading stage can be enlarged, so that the unit control is more stable. In addition, by correcting the loading return difference Tld, the unit can save more energy and operate more reliably when responding to the change of the environmental temperature or the change of the tail end heat load requirement, and the influence on the service life of the unit and the system fault are further reduced.

The low-temperature air source heat pump system executes the module control method of the low-temperature air source heat pump system, can solve the problem of liquid hammer failure caused by liquid accumulation of a compressor due to frequent start and stop of a unit in the prior art, can enlarge the range of a loading stage, and improves the operation stability and reliability of the unit.

Drawings

FIG. 1 is a schematic diagram of a cryogenic air source heat pump system according to an embodiment of the present invention;

FIG. 2 illustrates four stages of a method for controlling a module of a cryogenic air source heat pump system according to an embodiment of the present invention;

fig. 3 illustrates steps of a module control method of a cryogenic air source heat pump system according to an embodiment of the present invention.

In the figure:

100. an indoor unit; 201. a host; 202. a slave; 300. a controller; 400. a water pump; 501. an effluent temperature detector; 502. a backwater temperature detector.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

The embodiment provides a low-temperature air source heat pump system and a module control method thereof. As shown in fig. 1, the low-temperature air-source heat pump system includes an indoor unit 100, at least two low-temperature air-source heat pumps, and a controller 300. One of the at least two low-temperature air source heat pumps serves as a master 201, and the other low-temperature air source heat pumps serve as slaves 202. The controller 300 is arranged on the master machine and is respectively connected to all slave machines 202 in a communication mode and used for controlling the operation of all the low-temperature air source heat pumps.

All low-temperature air source heat pumps are connected in parallel, and a water pump 400 is arranged on the main water outlet pipeline and used for increasing the water flow speed. A water outlet temperature detector 501 is also arranged on the main water outlet pipeline and is used for measuring the water temperature in the main water outlet pipeline; a return water temperature detector 502 is provided on the total return water pipeline for measuring the temperature of water in the total return water pipeline.

When the ambient temperature changes, the heat load required by the building and the heating capacity generated by the units change. Specifically, as the ambient temperature decreases, the thermal load demand of the building increases and the heating capacity of the units decreases, at which time the units are loaded to a maximum. Because the loading and unloading running time is long, the starting and stopping times of the unit are few at the moment, and the unit is not influenced.

When the ambient temperature rises, the heat load of the building is reduced, the heating capacity of the unit is increased, and the regulation ratio of the single unit to the whole system is increased. Once the set heating return difference or the set loading return difference is small, the conditions that the unit needs to be unloaded after loading an energy level and then needs to be loaded easily occur, so that the unit needs to be started and stopped frequently, the service life and the reliability of the piping are influenced, the initial state of the unit is worse and worse, and the energy consumption is increased rapidly; and moreover, the starting time of the low-temperature air source heat pump unit is too short, so that the system circulation is not completely established, the compressor continuously runs with liquid, and the unit directly breaks down and cannot be started up when the compressor is accumulated to a certain degree.

In order to solve the above problem, as shown in fig. 2 and 3, the module control method performed by the low-temperature air source heat pump system is as follows: in the loading stage, the maintaining stage, the unloading stage and the emergency stop stage, the starting and the loading of the low-temperature air source heat pump unit are respectively and independently controlled, the value of the starting return difference Tdt is not related to the value of the loading return difference Tld, and the loading return difference Tld is corrected at least in the loading stage. By "disassociate" herein is meant that the value of the startup back difference Tdt and the value of the load back difference Tld no longer need to be equal, even though the end result in a certain application is that the value of the startup back difference Tdt equals the value of the load back difference Tld, which is an accidental event, unlike the prior art method of directly setting the value of the startup back difference Tdt equal to the value of the load back difference Tld.

The module control method enables the unit to be started and loaded independently by separating the starting return difference and the loading return difference of the unit, can reduce the starting and stopping times of all energy levels of the unit, enables the unit to run more efficiently and prolongs the service life of the unit, solves the problem of overlarge temperature difference between a keeping stage and a target temperature, improves the running stability and reliability of the unit, and is more energy-saving and efficient for a compressor and good in user experience; the range of the loading stage can be enlarged, so that the unit control is more stable. In addition, by correcting the loading return difference Tld, the unit can save more energy and operate more reliably when responding to the change of the environmental temperature or the change of the tail end heat load requirement, and the influence on the service life of the unit and the system fault are further reduced.

The specific method for correcting the load return difference Tld is not limited, and the load return difference Tld may be corrected according to a change in the ambient temperature or a change in the end thermal load demand. In this embodiment, the method preferably starts timing after the low-temperature air source heat pump system loads one energy level, and corrects the load return difference Tld when the timing duration when the instruction to enter the unloading stage is received is less than a first set Time Tzf, where the corrected load return difference Tld2 is (Tzf +1) × Tld/Time1, where Time1 is the actual running duration after timing, and Tzf +1 ensures the unit correction margin.

The loading return difference Tld is corrected by taking the first set time Tzf as a parameter, the number of times of starting and stopping the unit can be reduced, and the compressor can be ensured to reach a stable stage in each operation, so that a virtuous circle is formed, the failure rate of the unit is reduced, the operation stability of the unit is improved, and the service life of the unit is prolonged. And the starting and the stopping of the compressor are only carried out individually, the adjusting proportion of a single unit can be increased when the environmental temperature and the room load are changed, the compressor is prevented from being started and stopped frequently under the condition that the normal use is not influenced, and the service life of the compressor is prolonged.

The stable operation of the low-temperature air source heat pump unit generally needs three stages: in the initial stage, the time lasts for about 3 minutes, the opening degree of the electronic expansion valve is large in the initial stage, the motor of the motor is protected from being damaged, and the normal starting of the unit is ensured; in the adjusting stage, the duration is about 7-10 minutes, and PID adjustment is carried out on real-time feedback of the superheat degree through a unit; the unit then undergoes a stabilization phase. Once the unit is stopped without entering a stable stage, the next start-up is badly affected, and particularly, the unit system falls into a vicious circle in a frequent start-up and stop state.

In order to solve the above problem, the first set Time Tzf ∈ [18 minutes, 22 minutes ], preferably 19 minutes, 20 minutes, and 21 minutes, and when it is judged whether Time1 < Tzf in fig. 3, Tzf is directly written as 20 minutes. The low-temperature air source heat pump system can reach a stable state, the starting and stopping times are reduced, and negative effects on next starting are avoided.

On the basis of the above, the module control method further includes second set times Tzs, Tzs > Tzf. When the timing of the low-temperature air source heat pump system after being loaded with one energy level exceeds the second set time Tzs, the loading return difference Tld is not corrected. Wherein the second set time Tzs ∈ [23 minutes, 27 minutes ], preferably 24 minutes, 25 minutes, and 26 minutes.

On the basis of the above, the number of compressors at the initial start-up can be calculated. Specifically, the system return water temperature Tin is obtained through measurement, specific values of the target temperature Tset and the heating return difference Tdt are set, and the value is made to be Tset-Tin and is made to be Tset-Tset. When the delta T is larger than the Tdt, the low-temperature air source heat pump system is started, and the number Nneed of the compressors at the initial start is delta T multiplied by Cmax/Tmax, wherein the Cmax is the total number of the compressors in the low-temperature air source heat pump system, and the Tmax is the difference value between the target temperature Tset and the return water temperature Tin when the compressors are required to be fully opened. Wherein Tset, Tdt and Tmax are set parameter values, Tin and Cmax are detection values, and specifically, Cmax is the number of automatically detected on-line debugging confirmations. The number of the compressors required during initial startup is determined according to the delta T, Cmax and the Tmax, so that the condition that the unit is rapidly over a set target and is suddenly stopped due to sensor detection accuracy and feedback delay can be effectively avoided, and the problem of frequent start and stop of the unit is further solved. After the unit is started, whether the unit needs to be loaded or not is determined according to the feedback of entering the normal temperature, and whether the unit enters a keeping stage, an unloading stage or an emergency stop stage or not is determined.

When Tmax is larger than Tdt, the pre-opening quantity proportion of the compressor at the initial start-up is Tdt/Tmax, or the percentage is Tdt/Tmax multiplied by 100%. The number of compressors put into service in a group can be determined by adjusting two parameters, i.e., Tmax and Tdt. After a starting command is issued, the low-temperature air source heat pump unit starts a part of compressors in sequence, then the initial stage is finished, and loading or unloading is carried out according to the requirement. When Tmax is less than Tdt, all compressors are started at the initial start, and the scheme is not recommended because the scheme easily causes frequent start and stop of the unit.

After starting up, the unit can go through a loading stage, a holding stage, an unloading stage and an emergency stop stage. Tld is loading return difference, when the delta T is more than Tld, the loading phase is entered, and when the delta T is less than or equal to Tld, the maintaining phase is entered. Tuld is unloading return difference, and enters an unloading stage when the delta T is less than Tuld, and enters an emergency stop stage when the delta T is more than or equal to Tuld.

When the module control method is in a loading stage, loading an energy level (a parameter of stepless operation of a compressor, representing the heating capacity or power level of a heat pump) every other energy control period until all energy is loaded; when the module control method is in the keeping stage, keeping the current energy level and not acting; when the module control method is in an unloading stage, unloading an energy level every other energy control period until all the energy is unloaded; when the module control method is in the scram phase, an energy level is unloaded every preset time (e.g., every 1 second).

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.