WO2021135677A1 - Control method for automatically switching operation mode of water chilling unit - Google Patents

Abstract

The present invention relates to a control method for automatically switching an operation mode of a water chilling unit. The water chilling unit has a plurality of operation modes and comprises a water tank for providing hot water. The control method comprises: setting up a water temperature set value and a water tank temperature set value of the water chilling unit; according to the water temperature set value and the water tank temperature set value, dividing into a plurality of load demand regions, and selecting, for each load demand region, a corresponding operation mode from the plurality of operation modes; measuring an actual water temperature and an actual water tank temperature of the water chilling unit; and selecting one of the plurality of load demand regions according to the measured actual water temperature and actual water tank temperature, and according to the selected load demand region, automatically switching the water chilling unit to the corresponding operation mode. The control method for automatically selecting the operation mode of the water chilling unit according to an actual load demand change not only achieves the smart control of the water chilling unit, but also further improves the convenience of a user operation.

Description

Control method for automatically switching operation mode of chiller Technical field

The present invention relates to a method for controlling an air conditioning system, in particular to a control method for automatically switching the operation mode of a chiller.

Background technique

Water chillers generally conduct heat through water (called refrigerant), including but not limited to water-cooled chillers and air-cooled chillers. The chiller can adopt a vapor compression refrigeration cycle (for example, using a screw compressor or a scroll compressor) or an absorption refrigeration cycle. The chiller using the vapor compression refrigeration cycle first uses a refrigerant (such as Freon or other substitutes) to cool (refrigerate) or heat (heat) the water to a certain temperature (called "outlet water temperature" or "water supply temperature"); The cooled or heated water is then sent to the heat exchange coil of the central air conditioning system to cool or warm the air; the cooled or warmed air is then sent to the space that needs cooling or heating (conditioned space), such as an office Etc.; the water that transfers heat to the air is heated or cooled to a certain temperature (called "return water temperature") and then returned to the chiller to be cooled or heated again, thereby starting a new cooling or heating cycle.

Water chillers have been widely used at present, for example, they have developed into a type of central air-conditioning. At the same time, the various functions of the chiller have been gradually improved. For example, the same chiller can meet multiple requirements for refrigeration, heating, hot water production and heat recovery. The user selects different functional modes through the remote control or the buttons on the user terminal. For example, when the user needs cooling, the cooling mode is selected; when the user needs hot water, the hot water heating mode is selected; when both cooling and cooling are required When making hot water, select the heat recovery mode. The selection of these function modes requires the user to operate through the wire controller, so the intelligent control of the unit cannot be realized, and the convenience of operation is not enough.

Correspondingly, a new technical solution is needed in this field to solve the above-mentioned problems.

Summary of the invention

In order to solve the above-mentioned problems in the prior art, that is, to solve the technical problem that the operation mode of the existing chiller cannot be automatically switched, the present invention provides a control method for automatically switching the operation mode of the chiller, the chiller having Multiple operating modes and including a water tank that provides hot water, the control method includes: establishing a water temperature setting value and a water tank temperature setting value of the chiller; dividing more based on the water temperature setting value and the water tank temperature setting value A load demand area, and select a corresponding operation mode for each load demand area from the multiple operation modes; measure the actual water temperature and actual water tank temperature of the chiller; based on the measured actual water temperature and actual water tank temperature Select one of the multiple load demand zones, and automatically switch the chiller to the corresponding operation mode according to the selected load demand zone.

In the above-mentioned preferred technical solution of the control method for automatically switching the operation mode of the chiller, the control method includes a predetermined value hysteresis control.

In the above-mentioned preferred technical solution of the control method for automatically switching the operation mode of the chiller, the predetermined value hysteresis control includes 2 degrees Celsius hysteresis control.

In the preferred technical solution of the above-mentioned control method for automatically switching the operation mode of the chiller, the multiple operation modes include a cooling mode, a heating mode, a hot water mode, a heat recovery mode, a heating priority mode, and a standby mode .

In the preferred technical solution of the control method for automatically switching the operation mode of the chiller, the control method includes a summer control mode and a winter control mode. In the summer control mode, the cooling water temperature set value and the first Water tank temperature setting value, and dividing the multiple load demand zones based on the cooling water temperature setting value and the first water tank temperature setting value; in the winter control mode, establishing the heating water temperature setting value and the second The water tank temperature setting value, and the plurality of load demand zones are divided based on the heating water temperature setting value and the second water tank temperature setting value.

In the above-mentioned preferred technical solution of the control method for automatically switching the operation mode of the chiller, the set value of the cooling water temperature is 12°C, and the set value of the hot water temperature is 45°C.

In the above-mentioned preferred technical solution of the control method for automatically switching the operation mode of the chiller, the set temperature of the first water tank is 40°C, and the set temperature of the second water tank is 50°C.

In the preferred technical solution of the control method for automatically switching the operation mode of the chiller, in the summer control mode, the chiller includes a cooling mode, a hot water mode, a heat recovery mode, and a standby mode; In the winter control mode, the chiller includes a heating mode, a hot water mode, a heating priority mode, and a standby mode.

In the preferred technical solution of the above-mentioned control method for automatically switching the operation mode of the chiller, the summer control mode and the winter control mode can be automatically switched based on the ambient temperature or manually set.

In the above-mentioned preferred technical solution of the control method for automatically switching the operation mode of the chiller, the multiple load demand areas include nine load demand areas.

Those skilled in the art can understand that, in the technical solution of the control method for automatically switching the operation mode of the chiller of the present invention, a plurality of loads are divided according to the established water temperature setting value of the water chiller and the water tank temperature setting value. Demand area, and select a corresponding operating mode for each load demand area. When the chiller is running or in standby, measure the actual water temperature of the chiller and the actual water tank temperature. Select one of multiple load demand zones based on the measured actual water temperature and actual water tank temperature, and automatically switch the chiller to the corresponding operating mode according to the selected load demand zone. This control method that automatically selects the operating mode of the chiller based on actual load demand changes not only realizes the intelligent control of the chiller, but also further improves the convenience of user operations.

Preferably, the control method of the present invention adopts a predetermined value of hysteresis control, such as 2 degrees Celsius hysteresis control, which can avoid frequent conversion between operating modes caused by fluctuations in the water temperature of the chiller near the critical value and/or frequent startup of the chiller. Stop the problem.

Preferably, the summer control mode and the winter control mode set by the control method of the present invention can respectively meet the main needs of the user in a certain period of time, such as cooling or heating.

Description of the drawings

The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

Figure 1 is a flow chart of the control method for automatically switching the operating mode of the chiller according to the present invention;

2 is a flowchart of an embodiment of the summer control mode of the control method for automatically switching the operation mode of the chiller of the present invention;

Fig. 3 is a flowchart of an embodiment of the winter control mode of the control method for automatically switching the operation mode of the chiller of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention.

In order to solve the technical problem that the operation mode of the existing water chiller cannot be automatically switched, the present invention provides a control method for automatically switching the operation mode of the water chiller. The chiller has a variety of operating modes and includes a water tank that provides hot water. The control method includes: establishing the water temperature setting value and the water tank temperature setting value of the chiller (step S1); dividing a plurality of load demand areas based on the water temperature setting value and the water tank temperature setting value, and selecting from multiple operation modes Select a corresponding operating mode for each load demand zone (step S2); measure the actual water temperature and actual water tank temperature of the chiller (step S3); select the multiple load requirements based on the measured actual water temperature and actual water tank temperature According to the selected load demand area, the chiller is automatically switched to the corresponding operating mode (step S4).

In one or more embodiments, the multiple operation modes include cooling mode, heating mode, hot water heating mode, heat recovery mode, heating priority mode, and standby mode. The "cooling mode" generally refers to an operation mode in which the outdoor air-conditioning unit performs cooling operation and transfers the cold energy to the water system, and then realizes the user's indoor cooling demand through the water system. The "heating mode" usually refers to the operation mode in which the outdoor air-conditioning unit performs heating operation and transfers heat to the water system, and then realizes the heating demand of the user's indoor side through the water system. "Hot water mode" usually refers to the operation mode in which the outdoor air conditioning unit performs heating operation and transfers the heat to the water system, and then stores the hot water in the water tank to achieve the hot water demand of the user indoors. "Heat recovery mode" usually means that the outdoor air conditioning unit performs cooling and hot water operation at the same time and transfers the heat emitted by the cooling to the water system on the hot water side, and then the hot water is stored in the water tank to achieve the indoor side of the user. Simultaneous cooling and hot water demand operation mode. "Standby mode" usually refers to the state where the chiller is energized but stopped. "Heating priority mode" usually refers to the mode that first meets the heating demand when there are both heating and hot water demand. That is, the chiller has heating priority by default, so the chiller enters the heating mode first.

The "set value of water temperature" mentioned in this article generally refers to the set value of the return water temperature of the chiller. Correspondingly, the actual water temperature also refers to the actual return water temperature of the chiller. Alternatively, according to actual needs, the water temperature set value may also be the set value of the water supply temperature of the chiller. In this case, the actual water temperature should also be the actual water supply temperature.

The chillers submitted in this article can be chillers using vapor compression refrigeration cycles (such as screw chillers or scroll chillers), or chillers using absorption refrigeration cycles (such as lithium bromide absorption chillers). Chillers), but not limited to these types of chillers. In addition, these chillers are equipped with water tanks for storing and supplying hot water.

Unless there are clear instructions for the operation steps mentioned in this article, there is no requirement on the order of operations. For example, some operation steps can be implemented at the same time.

Fig. 1 is a flowchart of a control method for automatically switching the operation mode of a chiller according to the present invention. As shown in Figure 1, for a chiller with multiple operating modes and a water tank that provides hot water, in step S1, the control method first establishes the water temperature setting value of the chiller and the water tank temperature setting value. In step S2, the control method divides the user's load demand into multiple load demand areas based on the established water temperature set value and water tank temperature set value, and selects one for each load demand area from multiple operating modes Corresponding operating mode. When the chiller is running or on standby, the actual water temperature of the chiller and the actual water tank temperature are measured through step S3. Finally, in step S4, a load demand zone is selected from multiple load demand zones based on the measured actual water temperature and actual water tank temperature, and the chiller is automatically switched to the corresponding operating mode according to the selected load demand zone.

In one or more embodiments, the control method of the present invention includes a summer control mode and a winter control mode. In the summer control mode, the chiller can include cooling mode, hot water mode, heat recovery mode and standby mode, and can automatically switch between these modes based on load demand. In the winter control mode, the chiller can include heating mode, hot water mode, heating priority mode and standby mode, and can automatically switch between these modes based on load demand. The conversion between the summer control mode and the winter control mode can be automatically switched based on the outside environment temperature or manually set.

In one or more embodiments, both the summer control mode and the winter control mode adopt predetermined value hysteresis control. The predetermined value hysteresis control is the hysteresis control for the water temperature setting value and the water tank temperature setting value. The predetermined value may be, for example, 2 degrees Celsius. Alternatively, the predetermined value may also be a predetermined value lower than 2 degrees Celsius or higher than 2 degrees Celsius. This return difference control can increase the stability of the chiller and avoid frequent start and stop of the chiller. For example, in the cooling mode, when the chiller does not adopt the differential control, if the water temperature is set to 10℃, then when the water temperature of the chiller is lower than 10℃, the chiller will stop immediately; when the indoor load is high When it is large, the water temperature will quickly rise above 10°C, and the chiller will be turned on immediately, causing frequent start and stop of the chiller. When the chiller has a return difference of 2 degrees Celsius, when the water temperature is set to 10°C, the chiller will shut down when the water temperature is lower than 10°C-2°C, that is, 8°C; when the chiller is shut down, the water temperature will change It keeps rising, when it reaches 10℃+2℃, that is, 12℃, the chiller will start. Therefore, the hysteresis control method can effectively reduce the number of start and stop of the chiller, reduce energy consumption, and extend the service life of the corresponding components.

Fig. 2 is a flowchart of an embodiment of the summer control mode for automatically switching the operation mode of the chiller according to the present invention. In one or more embodiments, in the summer control mode, the chiller has multiple operation modes: cooling mode, hot water heating mode, heat recovery mode, and standby mode. As shown in Fig. 2, in this embodiment, the control method for automatically switching the operation mode of the chiller first establishes the set value of the chilled water temperature of the chiller and the set value of the first water tank temperature (step S1'). In step S2', multiple load demand zones are divided based on the cooling water temperature set value and the first water tank temperature set value, and a corresponding operating mode is selected for each load demand zone from the multiple operating modes. In step S3, when the chiller is running or on standby, the actual water temperature of the chiller and the actual water tank temperature are measured. Finally, in step S4, one of the multiple load demand zones is selected based on the measured actual water temperature and the actual water tank temperature, and the chiller is automatically switched to the corresponding operation mode according to the selected load demand zone.

In one or more embodiments, in the summer control mode, nine load demand zones can be divided based on the set value of the cooling water temperature and the set value of the first water tank temperature. For example, as shown in Table 1 below, taking the water temperature of the chiller unit as the ordinate and the water tank temperature as the abscissa, through the first water tank temperature setting value, the cooling water temperature setting value and the return difference of 2 degrees Celsius, the load demand can be calculated Divided into nine load demand areas (form a nine-square grid): A1, A2, A3, B1, B2, B3, C1, C2, C3. For example, when the actual water temperature of the chiller is higher than the cooling water temperature set value +2, and the actual water tank temperature is lower than the first water tank temperature set value -2, the actual load demand will fall into the area of A1. Therefore, the actual water temperature and the actual water tank temperature change represent the actual load demand change, so that the actual load demand falls into different load demand areas. In one or more embodiments, the first water tank temperature setting value may be 40°C, and the cooling water temperature setting value may be 12°C. Alternatively, in other embodiments, the first water tank temperature setting value and the cooling water temperature setting value may also adopt other suitable values respectively. Alternatively, in other embodiments, the load demand area is not limited to nine, but can be less than or more than nine according to actual needs.

Table 1:

For each of the above nine load demand zones, the corresponding operating mode can be selected. For example, as shown in Table 2 below, in the load demand area A1, because the actual water temperature is high and the actual water tank temperature is low, there is a demand for cooling and hot water at the same time, so the heat recovery mode is selected for the A1 area. In other words, when the actual water temperature of the chiller is higher than the cooling water temperature set value +2, and the actual water tank temperature is lower than the first water tank temperature set value-2, the chiller will automatically switch to the heat recovery mode. Continuing to refer to Table 2, load demand zones A2 and A3 correspond to cooling modes, load demand zones B1 and C1 correspond to hot water mode, and load demand zones B2, B3, C2, and C3 all correspond to standby mode.

Table 2:

"1" means need to run; "0" means no need to run

Area	Refrigeration demand mark	Hot water demand mark	Operation mode of chiller
A1	1	1	Heat recovery
A2	1	0	Refrigeration
A3	1	0	Refrigeration
B1	0	1	Hot water
B2	0	0	Standby
B3	0	0	Standby
C1	0	1	Hot water
C2	0	0	Standby
C3	0	0	Standby

Fig. 3 is a flowchart of an embodiment of the winter control mode for automatically switching the operation mode of the chiller according to the present invention. In one or more embodiments, in the winter control mode, the chiller also has multiple operation modes: a heating mode, a hot water mode, a heating priority mode, and a standby mode. As shown in Fig. 3, in this embodiment, the control method for automatically switching the operating mode of the chiller first establishes the hot water temperature setting value of the chiller unit and the second water tank temperature setting value (step S1"). In step S2", a plurality of load demand areas are divided based on the heating water temperature setting value and the second water tank temperature setting value, and a corresponding operation mode is selected for each load demand area from the plurality of operation modes. In step S3, when the chiller is running or on standby, the actual water temperature of the chiller and the actual water tank temperature are measured. Finally, in step S4, one of multiple load demand zones is selected based on the measured actual water temperature and actual water tank temperature, and the chiller is automatically switched to the corresponding operating mode according to the selected load demand zone.

In one or more embodiments, in the winter control mode, nine load demand zones can also be divided based on the heating water temperature setting value and the second water tank temperature setting value. For example, as shown in Table 3 below, taking the water temperature of the chiller unit as the ordinate and the temperature of the water tank as the abscissa, through the second water tank temperature setting value, the heating water temperature setting value and the return difference of 2 degrees Celsius, you can Load demand is divided into nine load demand areas (form a nine-square grid): A1, A2, A3, B1, B2, B3, C1, C2, C3. For example, when the actual water temperature of the chiller is higher than the hot water temperature setting value +2, and the actual water tank temperature is lower than the second water tank temperature setting value -2, the actual load demand will fall into the area of A1. In one or more embodiments, the second water tank temperature setting value may be 50°C, and the hot water temperature setting value may be 45°C. Alternatively, in other embodiments, according to actual needs, the second water tank temperature setting value and the hot water temperature setting value may also adopt other suitable values, respectively.

table 3:

For each of the nine load demand zones in the winter control mode, the corresponding operating mode can also be selected. For example, as shown in Table 4 below, in the load demand zone A1, because the actual water temperature is high and the actual water tank temperature is low, there is no need for heating, but there is a demand for hot water, so the system is selected for zone A1. Hot water mode. In other words, in winter, when the actual water temperature of the chiller is higher than the hot water temperature setting +2, and the actual water tank temperature is lower than the second water tank temperature setting -2, the chiller will automatically switch to the hot water mode. Similarly, the load demand zone B1 also corresponds to the hot water heating mode. Continuing to refer to Table 4, the load demand areas A2, A3, B2, and B3 all correspond to the standby mode, the load demand area C1 corresponds to the heating priority mode, and the load demand areas C2 and C3 both correspond to the heating mode.

Table 4:

"1" means need to run; "0" means no need to run

Load demand area	Heating demand mark	Hot water demand mark	Chiller operating mode
A1	0	1	Hot water
A2	0	0	Standby
A3	0	0	Standby
B1	0	1	Hot water
B2	0	0	Standby
B3	0	0	Standby
C1	1	1	Heating priority
C2	1	0	Heating
C3	1	0	Heating

Through the automatic conversion of the operation mode in the summer and winter control modes, the control method of the present invention can realize the intelligent operation of the chiller without manual operation of the operation mode conversion, thus effectively improving the convenience of the chiller. In summer, the chiller can automatically enter the heat recovery mode (such as full heat recovery), and can also realize the recovery and utilization of the heat emitted by the chiller during cooling, thus reducing the energy consumption of the chiller and realizing the chiller Energy saving. The control method of the present invention effectively avoids the frequent start and stop of the chiller when the water temperature is near the critical value through the hysteresis control, reduces the frequent actions of components, and increases the service life of the chiller.

So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims (10)

1. A control method for automatically switching the operation mode of a water chiller, characterized in that the water chiller has multiple operation modes and includes a water tank for providing hot water, and the control method includes:

   Establishing the water temperature setting value and the water tank temperature setting value of the chiller;

   Dividing a plurality of load demand areas based on the water temperature setting value and the water tank temperature setting value, and selecting a corresponding operation mode for each load demand area from the multiple operation modes;

   Measuring the actual water temperature and the actual water tank temperature of the chiller;

   One of the multiple load demand zones is selected based on the measured actual water temperature and the actual water tank temperature, and the chiller is automatically switched to the corresponding operation mode according to the selected load demand zone.
2. The control method for automatically switching the operating mode of the chiller according to claim 1, wherein the control method includes a predetermined value hysteresis control.
3. The control method for automatically switching the operation mode of the chiller according to claim 2, wherein the predetermined value hysteresis control includes 2 degrees Celsius hysteresis control.
4. The control method for automatically switching the operation mode of the chiller according to claim 1 or 2, wherein the multiple operation modes include cooling mode, heating mode, hot water mode, heat recovery mode, and heating mode. Thermal priority mode and standby mode.
5. The control method for automatically switching the operation mode of the chiller according to claim 1 or 2, wherein the control method includes a summer control mode and a winter control mode, and the cooling water temperature is established in the summer control mode. Setting value and a first water tank temperature setting value, and dividing the multiple load demand areas based on the cooling water temperature setting value and the first water tank temperature setting value; in the winter control mode, establishing a heating water temperature Setting value and a second water tank temperature setting value, and dividing the plurality of load demand areas based on the heating water temperature setting value and the second water tank temperature setting value.
6. The control method for automatically switching the operation mode of the chiller according to claim 5, wherein the set value of the cooling water temperature is 12°C, and the set value of the heating water temperature is 45°C.
7. The control method for automatically switching the operating mode of a chiller according to claim 5, wherein the first water tank temperature setting value is 40°C, and the second water tank temperature setting value is 50°C .
8. The control method for automatically switching the operating mode of the chiller according to claim 5, wherein, in the summer control mode, the chiller includes a cooling mode, a hot water mode, a heat recovery mode, and a standby mode. Mode; in the winter control mode, the chiller includes a heating mode, a hot water mode, a heating priority mode, and a standby mode.
9. The control method for automatically switching the operation mode of the chiller according to claim 5, wherein the control mode between the summer control mode and the winter control mode can be automatically switched based on the ambient temperature or manually set.
10. According to the control method for automatically switching the operation mode of the chiller according to claim 1 or 2, the plurality of load demand zones includes nine load demand zones.

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