阅读说明：本技术 多模块冷水机组及其调度控制方法 (Multi-module water chilling unit and scheduling control method thereof ) 是由 李顺意 林少丹 陈培生 程琦 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种带自然冷却的多模块冷水机组及其调度控制方法。所述调度控制方法包括：开机后,控制器根据各模块的累计运行时间,按照“少运行,先开启”的原则依次对各模块发出开启或加载指令；当冷水机组满足卸载或关闭条件时,按照“多运行,先关闭”的原则依次对各模块的发出卸载或关闭指令；若所有模块的累计运行时间相同,则按照模块的命名或拨码地址顺序依次控制。本发明提出的调度控制方法增强了机组运行的稳定性,更好地发挥其高效节能的优点,同时提高了机组运行的寿命。(The invention discloses a multi-module water chilling unit with natural cooling and a scheduling control method thereof. The scheduling control method comprises the following steps: after starting up, the controller sequentially sends opening or loading instructions to the modules according to the accumulated operation time of the modules and the principle of 'less operation, first opening'; when the water chilling unit meets the unloading or closing condition, the unloading or closing instructions are sent to the modules in sequence according to the principle of 'multi-operation and first closing'; and if the accumulated running time of all the modules is the same, sequentially controlling according to the naming or dialing address sequence of the modules. The scheduling control method provided by the invention enhances the stability of unit operation, better exerts the advantages of high efficiency and energy conservation, and simultaneously prolongs the service life of unit operation.)

1. A dispatching control method of a multi-module water chilling unit is characterized in that after the water chilling unit is started, a controller sequentially sends starting or loading instructions to each module according to the accumulated running time of each module and the principle of 'less running, first starting'; when the water chilling unit meets the unloading or closing condition, the unloading or closing instructions are sent to the modules in sequence according to the principle of 'multi-operation and first closing'; and if the accumulated running time of all the modules is the same, sequentially controlling according to the naming or dialing address sequence of the modules.

2. The scheduling control method of claim 1 wherein if it is the turn-on module that is in a fault state or the turn-on condition is not satisfied, then turning on the module that follows.

3. The scheduling control method of claim 1 wherein the controller detects the load deviation value of the chiller in real time and issues a load adjustment command to the corresponding module based on the load deviation value.

4. The dispatch control method of claim 3, wherein the load offset value is a difference between an actual chilled effluent temperature and a chilled effluent set temperature, and wherein the loading is performed when the load offset value is greater than a set value C and the unloading is performed when the load offset value is less than D; otherwise, the current state is kept running.

5. The dispatch control method of any one of claims 1-4, wherein the chiller operation modes comprise: a compression refrigeration mode, a free cooling mode or a hybrid refrigeration mode.

6. The scheduling control method of claim 5, comprising the steps of:

after the water chilling unit is started, judging whether the natural cooling mode operation condition is met, and if the natural cooling mode operation condition is met, entering the natural cooling mode operation; and if not, entering a compression refrigeration mode to operate.

7. The scheduling control method of claim 6, wherein after entering the natural cooling mode operation, monitoring and judging whether a compressor start condition is satisfied in real time, and if not, maintaining the natural cooling mode operation; and if so, entering a mixed refrigeration mode to operate.

8. The scheduling control method according to claim 6, wherein after entering the compression refrigeration mode, the operation is monitored and judged in real time whether a liquid pump starting condition is met, and if not, the operation in the compression refrigeration mode is maintained; and if so, entering a mixed refrigeration mode to operate.

9. The scheduling control method of claim 7 or 8, wherein after entering the hybrid refrigeration mode operation, monitoring and judging whether a compressor closing condition is satisfied in real time, and if not, maintaining the hybrid refrigeration mode operation; if so, judging whether the liquid pump closing condition is met, and if not, maintaining the natural cooling mode to run; if yes, stopping the machine for standby.

10. The scheduling control method according to claim 7 or 8, wherein in the hybrid refrigeration mode, when the controller detects that the load deviation value meets the loading condition, the liquid pumps are loaded preferentially, and when all the liquid pumps are loaded to full load, the compressors are loaded again; and when the load deviation value meets the load unloading condition, unloading the compressors preferentially, keeping running after the compressors are unloaded to the minimum frequency, then unloading the next sequential compressors, and after all the compressors are unloaded to the minimum frequency and run for n2 minutes cumulatively, if the load deviation value also meets the unloading condition, closing the compressors sequentially and entering a natural cooling mode.

11. The schedule control method of claim 5 wherein said free cooling mode operating conditions are:

(1) actual refrigeration outlet water temperature T_{Go out}The refrigeration water outlet set temperature B + (the air conditioner compressor opening temperature deviation delta T3/the number of compressors) + a refrigeration correction value A;

(2) the natural cooling liquid pump is shut down for more than n1 minutes;

(3) the actual refrigeration outlet water temperature drop rate V is less than or equal to the starting water temperature change rate limiting value delta Tt 1;

(4) the corresponding state of the refrigeration compressor is the off state.

12. The schedule control method according to claim 7, wherein said compressor on condition is: and after all the liquid pumps are loaded to full load, the actual refrigerating effluent temperature still cannot reach the refrigerating effluent set temperature B, and then the compressor is started to enter a mixed refrigerating mode for operation.

13. The scheduling control method of claim 8 wherein the liquid pump turn-on condition is: when the refrigerating outlet water set temperature B-the ambient temperature T is detected for n1 minutes continuously_{Ring (C)}When the liquid pump is closed and the temperature difference is delta T5-T1, the pair is openedAnd (5) feeding a liquid pump to enter a mixed refrigeration mode for operation.

14. The schedule control method of claim 9 wherein said compressor off condition is: and after unloading all the compressors to the minimum frequency and performing cumulative operation for n2 minutes, if the unloading condition is met, sequentially turning off the compressors and entering a natural cooling mode for operation.

15. The scheduling control method of claim 9 wherein the liquid pump shut-down condition is: when the refrigerating water outlet set temperature B + refrigerating correction value A-ambient temperature T is detected for n3 minutes continuously_{Ring (C)}And (4) setting the temperature difference delta T5-T2 for liquid pump closing, starting unloading and closing each module liquid pump until all liquid pumps are closed.

16. A multi-module chiller, each module consisting of a compression refrigeration cycle and a natural cooling cycle, wherein the multi-module chiller operates using the dispatch control method of any one of claims 1-15.

Technical Field

The invention relates to the technical field of air conditioners, in particular to a multi-module water chilling unit with natural cooling and a scheduling control method thereof.

Background

With the rapid development of internet technology, big data application becomes the core of information engineering at the present stage, and the scale and number of data centers are continuously developed. The data center server can generate very high heat in the process of storing and processing a large amount of data, and effective and stable cooling measures are required to be guaranteed for guaranteeing efficient and reliable operation of data center server equipment. The traditional air conditioning system uses a compressor unit for refrigeration, and has the problem of high energy consumption in the engineering application of a data center which needs annual refrigeration. Therefore, the application of the natural cooling water chilling unit is available. In the transition season with lower ambient temperature and winter, the natural cooling unit uses the liquid pump to replace the compressor to refrigerate, and the running energy consumption of the water chilling unit is greatly reduced.

For large data centers, multiple cooling unit modules are typically included. The conventional unit with natural cooling does not consider the coordinated scheduling control of multiple modules, but adopts a strategy of uniformly controlling modules of each unit, namely when the detected ambient temperature meets the starting condition of the natural cooling function, all the modules simultaneously execute a command of switching to the natural cooling function. The control mode is simple, the characteristic of energy saving in operation of the natural cooling unit cannot be exerted to the maximum, and meanwhile, the problem of unstable operation due to fluctuation of output cold quantity is easily caused, so that the data center server equipment is in danger of failure.

Disclosure of Invention

The invention provides a multi-module water chilling unit with natural cooling and a scheduling control method thereof, which aim to solve the technical problems of unstable load adjustment and incapability of achieving optimal energy efficiency caused by multi-module control in the prior art.

The invention provides a dispatching control method of a multi-module water chilling unit, wherein after starting, a controller sequentially sends starting or loading instructions to each module according to the accumulated running time of each module and the principle of 'less running and starting firstly'; when the water chilling unit meets the unloading or closing condition, the unloading or closing instructions are sent to the modules in sequence according to the principle of 'multi-operation and first closing'; and if the accumulated running time of all the modules is the same, sequentially controlling according to the naming or dialing address sequence of the modules.

If it is the turn-on module that is in the fault state or the turn-on condition is not satisfied, then the module following it is turned on.

And the controller of the water chilling unit detects the load deviation value of the water chilling unit in real time and sends a load adjusting instruction to the corresponding module according to the load deviation value.

The load deviation value is the difference value between the actual refrigeration effluent temperature and the refrigeration effluent set temperature, and when the load deviation value is greater than a set value C, the load is loaded, and when the load deviation value is less than D, the load is unloaded; otherwise, the current state is kept running.

The operation modes of the water chilling unit comprise: a compression refrigeration mode, a free cooling mode or a hybrid refrigeration mode.

The scheduling control method provided by the invention comprises the following steps:

after the water chilling unit is started, judging whether the natural cooling mode operation condition is met, and if the natural cooling mode operation condition is met, entering the natural cooling mode operation; if not, entering a compression refrigeration mode to operate;

after the natural cooling mode is started, monitoring and judging whether the starting condition of the compressor is met or not in real time, and if the starting condition of the compressor is not met, maintaining the natural cooling mode to run; if yes, entering a mixed refrigeration mode to operate;

after entering the compression refrigeration mode to operate, monitoring and judging whether a liquid pump starting condition is met or not in real time, and if not, maintaining the compression refrigeration mode to operate; if yes, entering a mixed refrigeration mode to operate;

after entering the mixed refrigeration mode to operate, monitoring and judging whether the compressor closing condition is met or not in real time, and if not, maintaining the mixed refrigeration mode to operate; if so, judging whether the liquid pump closing condition is met, and if not, maintaining the natural cooling mode to run; if yes, stopping the machine for standby.

In the mixed refrigeration mode, when the controller detects that the load deviation value meets the loading condition, the liquid pumps are loaded preferentially, and when all the liquid pumps are loaded to full load, the compressor is loaded; and when the load deviation value meets the load unloading condition, unloading the compressors preferentially, keeping running after the compressors are unloaded to the minimum frequency, then unloading the next sequential compressors, and after all the compressors are unloaded to the minimum frequency and run for n2 minutes cumulatively, if the load deviation value also meets the unloading condition, closing the compressors sequentially and entering a natural cooling mode.

The natural cooling mode operating conditions are:

(1) actual refrigeration outlet water temperature T_{Go out}The refrigeration water outlet set temperature B + (the air conditioner compressor opening temperature deviation delta T3/the number of compressors) + a refrigeration correction value A;

(2) the natural cooling liquid pump is shut down for more than n1 minutes;

(3) the actual refrigeration outlet water temperature drop rate V is less than or equal to the starting water temperature change rate limiting value delta Tt 1;

(4) the corresponding state of the refrigeration compressor is the off state.

The compressor starting conditions are as follows: and after all the liquid pumps are loaded to full load, the actual refrigerating effluent temperature still cannot reach the refrigerating effluent set temperature B, and then the compressor is started to enter a mixed refrigerating mode for operation.

The liquid pump starting conditions are as follows: when the refrigerating outlet water set temperature B-the ambient temperature T is detected for n1 minutes continuously_{Ring (C)}And when the temperature difference delta T5-T1 is set when the liquid pump is closed, starting the corresponding liquid pump and entering a mixed refrigeration mode to operate.

The compressor off conditions are: and after unloading all the compressors to the minimum frequency and performing cumulative operation for n2 minutes, if the unloading condition is met, sequentially turning off the compressors and entering a natural cooling mode for operation.

The liquid pump shut-down conditions are as follows: when the refrigerating water outlet set temperature B + refrigerating correction value A-ambient temperature T is detected for n3 minutes continuously_{Ring (C)}And (4) setting the temperature difference delta T5-T2 for liquid pump closing, starting unloading and closing each module liquid pump until all liquid pumps are closed.

The invention also provides a multi-module water chilling unit, each module consists of a compression refrigeration cycle and a natural cooling cycle, and the multi-module water chilling unit operates by adopting the scheduling control method.

Compared with the prior art, the dispatching control method of the multi-module water chilling unit with natural cooling, provided by the invention, has the advantages of enhancing the stability of unit operation, better playing the advantages of high efficiency and energy conservation and prolonging the service life of the unit operation.

Drawings

FIG. 1 is a system diagram of modules in a chiller according to the present invention;

FIG. 2 is a flow chart of module scheduling control during startup or loading;

FIG. 3 is a flow chart of module scheduling control during unloading or shutdown;

fig. 4 is a control flow chart for switching the operation modes of the water chilling unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and examples. It should be understood that the following specific examples are only for illustrating the present invention and are not to be construed as limiting the present invention.

The invention provides a multi-module water chilling unit scheduling control strategy with natural cooling, which is characterized in that the control strategy is used for cooperatively scheduling multiple modules of a unit by detecting and judging the accumulated operation time of each module, so that the unit stably operates under all working conditions, and meanwhile, an energy-saving operation mode is selected to operate according to the load deviation of the water chilling unit, so that the operation performance is improved, and the energy consumption is further reduced.

The water chilling unit comprises a plurality of modules, each module is used as a refrigeration unit and comprises a compressor and a liquid pump, and the compressor is responsible for working in a compression refrigeration mode and a mixed refrigeration mode; the liquid pump is responsible for operating in a natural cooling mode and a hybrid cooling mode. Each module is distinguished by a dial-up address and named. For example, a binary two-dial distinguishing module may be used, with dial 00 being module one, dial 01 being module two, dial 10 being module three, dial 11 being module four, etc.

As shown in fig. 1, each module includes a compression refrigeration cycle and a natural cooling cycle. The compression refrigeration cycle is composed of a compressor 1, a condenser 2, an expansion valve 3, and an evaporator 4. In this embodiment, the compressor is an air-cooled screw chiller. The natural cooling circulation consists of a heat exchanger 5, a liquid pump 6 and a surface cooler 7. In this embodiment, the heat exchanger 5 is a plate heat exchanger, and is disposed in a return pipe of chilled water in the evaporator 4, and water in the natural cooling cycle exchanges heat with return water of the chilled water. The surface cooler and the condenser are arranged together and share the fan, so that the equipment cost is reduced. The cold energy generated by the natural cooling circulation is transmitted to the terminal device through the heat exchanger 5 and the chilled water pipeline.

The multi-module scheduling control method provided by the invention comprises the following steps: after starting up, the controller sequentially sends opening or loading instructions to the modules according to the accumulated operation time of the modules and the principle of 'less operation, first opening'; when the water chilling unit meets the unloading or closing condition, the unloading or closing instructions are sent to the modules in sequence according to the principle of 'multi-operation and first closing'; and if the accumulated running time of all the modules is the same, sequentially controlling according to the naming or dialing address sequence of the modules.

When a user operates and starts the computer, the controller records the accumulated operation time of each module, judges according to the accumulated operation time of each module, preferentially starts the modules with less accumulated operation time, ensures that the operation time of each module is similar, and avoids the situation that the difference of the accumulated operation time of each module is larger. If the accumulated running time of all modules is the same, the modules are started or loaded in sequence from small to large according to the naming or dialing addresses of the modules, as shown in fig. 2. When the modules meet the unloading or closing condition, the action sequence of each module is opposite to the opening/loading sequence, and the modules are unloaded or closed in sequence from a plurality of orders according to the accumulated running time of the modules. If the accumulated running time of all the modules is the same, the modules are unloaded or closed in turn according to the naming or dialing addresses of the modules from large to small, as shown in fig. 3. The action interval time of each module is not less than 2 minutes to the electric current is big when avoiding each module to start simultaneously, causes the impact to unit circuit and electric wire netting, and the interval time can set up according to particular case. If there is a fault in the module whose turn is to be turned on or the turn-on condition is not satisfied, the module following it is turned on.

And the loading and unloading of the modules are controlled according to the load deviation condition, and the modules are in standby according to the opening or closing scheduling principle.

Load adjustment of the water chilling unit: and the controller sends a loading, maintaining or unloading instruction to the compressor or the liquid pump according to the load deviation value, so that the load of the unit module is adjusted. The load deviation value is the actual refrigerating outlet water temperature (referring to the evaporator outlet water temperature) T_{Go out}And the difference value of the refrigerating water outlet set temperature B. When the load deviation value is greater than the set value C, the embodiment C is 2, and loading is carried out; when the load deviation value is smaller than the set value D, if the embodiment D is 0, unloading is carried out; otherwise, the existing operation mode is maintained.

The running modes of the water chilling unit comprise: a compression refrigeration mode, a free cooling mode, and a hybrid refrigeration mode. In the compression refrigeration mode, the unit only refrigerates through the compressor, and all natural cooling liquid pumps do not work. In the natural cooling mode, the unit is refrigerated only by the liquid pump, and all compressors do not work. In the hybrid refrigeration mode, the unit liquid pump and the compressor participate in the refrigeration operation at the same time.

When the environment temperature is higher, the compressor is adopted for refrigeration to meet the requirements of users, the mode technology is mature, and the refrigeration quantity is stable; when the environmental temperature is low, a mixed refrigeration mode is adopted to utilize a natural cold source to reduce energy consumption and improve energy efficiency; and the air conditioner enters a natural cooling mode after the environmental temperature is reduced again, the compressor is closed in the mode, the condition that the system pressure difference is low when the low-temperature compressor is used for refrigerating is avoided, the system operation stability is high, a natural cold source is fully utilized, and the energy efficiency is high.

Fig. 4 is a control flow chart of the operation mode switching of the water chilling unit. The startup and shutdown instruction is controlled by a user, the startup is coordinated according to the principle of 'less running and first startup' after standby, and the loading instruction of each module is triggered by the controller according to the load deviation.

When a user operates on a display panel to send a starting instruction, an air conditioner water pump (a user side chilled water pump, non-unit configuration and not shown in a system diagram) is immediately started to operate for a period of time delta tk, wherein the time is the advanced starting time of the air conditioner water pump and is 3min by default. And the unit controller starts to detect whether the natural cooling mode operation condition is met, and when the natural cooling mode operation condition is met, the unit enters the natural cooling mode operation, otherwise, the unit enters the compressor refrigeration mode operation. The natural cooling mode operating conditions were:

(1) the actual refrigeration outlet water temperature is greater than the refrigeration outlet water set temperature B + (the opening temperature deviation delta T3 of the air conditioner compressor/the number of the compressors) + a refrigeration correction value A;

(2) the natural cooling liquid pump is shut down for more than n1 minutes;

(3) the actual refrigeration outlet water temperature drop rate is less than or equal to the starting water temperature change rate limit value delta Tt 1;

(4) the corresponding state of the refrigeration compressor is the off state.

The above 4 conditions are simultaneously satisfied to enter the natural cooling mode for operation. In the natural cooling mode, the water chilling unit only refrigerates through the liquid pump, and all the compressors do not work.

And in the natural cooling mode, the controller sends an action instruction to the liquid pumps of each module according to the load deviation value, and after all the liquid pumps are loaded to full load and the actual refrigeration outlet water temperature still does not reach the refrigeration outlet water set temperature B, the compressor is started to enter the mixed refrigeration mode.

And when the natural cooling mode operation condition is not met after the machine is started, the machine enters a compression refrigeration mode to operate. In the compressor refrigeration mode, when the first module compressor is started to operate for 1 minute according to the initial frequency, the controller starts to detect the natural cooling function starting condition. When the refrigerating water outlet set temperature B-the ambient temperature T is detected for n1 minutes continuously_{Ring (C)}When the liquid pump is closed and the temperature difference is set to be delta T5-T1, in the embodiment, T1 is 5 degrees, the natural cooling liquid pump is correspondingly started, and the unit enters a mixed refrigeration mode.

In the hybrid cooling mode, the liquid pump and the compressor participate in the cooling operation at the same time. When the controller detects that the load deviation value meets the loading condition, the liquid pumps are loaded preferentially, and when all the liquid pumps are loaded to full load, the compressor is loaded. When the load deviation value meets the load unloading condition, the compressor is unloaded preferentially, the compressor keeps running after being unloaded to the minimum frequency, then the next sequential compressor is unloaded, and when all the compressors are unloaded to the minimum frequencyAfter the frequency is accumulated and the operation is carried out for n2 minutes, if the unloading condition is met, the compressors are closed in sequence, and the natural cooling mode is entered. The compressor must be run for a minimum of 3 minutes before allowing shut down. Under the mixed refrigeration mode, the controller detects the closing condition of the natural cooling liquid pump, and when the refrigeration water outlet set temperature B + the refrigeration correction value A-the environment temperature T is detected for n3 minutes continuously_{Ring (C)}And when the temperature difference delta T5-T2 is less than or equal to the liquid pump closing setting temperature difference, and the T2 is 10 degrees in the embodiment, unloading and closing each module liquid pump are started until all the liquid pumps are closed, and the unit is stopped to enter a standby state.

The parameters referred to above may be set, in this embodiment:

a is a refrigeration correction value, and the default is 1;

b is the refrigeration water outlet set temperature, and the default is 7 ℃;

delta tk is the air conditioner water pump opening time in advance, and the default is 3min

Delta T3 is the air condition compressor opening temperature deviation, and the default is 5 ℃;

Δ Tt1 is the start water temperature rate of change limit, default 0.5 ℃;

Δ T5 is the liquid pump shut-off temperature differential setting, defaulted to 15 ℃.

The values C were 2, D was 0, n1 was 1 minute, n2 was 3 minutes, n3 was 5 minutes, T1 was 5 degrees, and T2 was 10 degrees.

In an embodiment, the method for scheduling and controlling a multi-module chiller according to the present invention includes the following steps:

after the water chilling unit is started, judging whether the natural cooling mode operation condition is met, and if the natural cooling mode operation condition is met, entering the natural cooling mode operation; if not, entering a compression refrigeration mode to operate;

after the natural cooling mode is started, monitoring and judging whether the starting condition of the compressor is met or not in real time, and if the starting condition of the compressor is not met, maintaining the natural cooling mode to run; if yes, entering a mixed refrigeration mode to operate;

after entering the compression refrigeration mode to operate, monitoring and judging whether a liquid pump starting condition is met or not in real time, and if not, maintaining the compression refrigeration mode to operate; if yes, entering a mixed refrigeration mode to operate;

after entering the mixed refrigeration mode to operate, monitoring and judging whether the compressor closing condition is met or not in real time, and if not, maintaining the mixed refrigeration mode to operate; if so, judging whether the liquid pump closing condition is met, and if not, maintaining the natural cooling mode to run; if yes, stopping the machine for standby.

The dispatching control strategy of the water chilling unit with the natural cooling multiple modules provided by the invention judges through detecting data such as load deviation, accumulated running time of a liquid pump and a compressor, and the like, carries out cooperative dispatching on multiple modules of the unit, selects a relatively energy-saving running mode combination, enables the unit to run stably under all working conditions, simultaneously improves the running performance, reduces the energy consumption, and prolongs the running life of the unit.

The foregoing is considered as illustrative only of the embodiments of the invention. It should be understood that any modifications, equivalents and changes made within the spirit and framework of the inventive concept are intended to be included within the scope of the present invention.