JP7451066B2 - Air conditioning heat source control system and air conditioning heat source control method - Google Patents

Description

The present invention relates to an air conditioning heat source control system and an air conditioning heat source control method that supply cold water or hot water from a heat source device to an air conditioner using a circulation pump.

When controlling the heat source for air conditioning, the efficiency of the heat source device can be improved by increasing the water supply temperature of the heat source device during partial load. However, in order to raise the water supply temperature of the heat source equipment and obtain the same performance, it is necessary to increase the amount of water supplied to the heat source equipment, which increases the transport power. As described above, there is a trade-off relationship between improving the efficiency of the heat source equipment and increasing the transport power, so if you blindly increase the water supply temperature of the heat source equipment, the energy consumption may actually increase.

Conventionally, as a technology for controlling an air conditioning heat source, for example, an air conditioning heat source system and a method for controlling an air conditioning heat source system described in Patent Document 1, a water supply temperature control device and method described in Patent Document 2, and a method described in Patent Document 3. Load-responsive air conditioning systems and methods have been proposed.

Japanese Patent Application Publication No. 2003-262384 Patent No. 5320128 Patent No. 6994218

However, the invention described in Patent Document 1 described above requires a lot of input data and complicated calculations to find the optimal solution. In addition, a large number of sensors and calculation devices are required, and calculation software also needs to be developed individually, which increases costs and cannot be said to be highly versatile.

Further, the invention described in Patent Document 2 has the problem that a data storage device is required because it is a learning type, and the calculation method is also complicated.

Furthermore, the invention described in Patent Document 3 merely discloses a method of switching between variable water supply temperature and variable pressure using control valve information, and does not disclose a method of controlling the water supply temperature to the optimum temperature that minimizes energy consumption. Since it is not disclosed, it is not possible to maximize energy savings.

In this way, none of the above-mentioned inventions is a method that can be commonly used in buildings with different specifications, numbers, and control methods of heat sources and air conditioning equipment, and requires a lot of time and cost each time to apply variable flow rate (VWV). It is necessary to develop and maintain the logic for variable water volume (VWT) control and variable water temperature (VWT) control, and there are common issues such as low cost effectiveness and low versatility.

The present invention has been made to solve the above-mentioned problems, and provides an air conditioning heat source control system and an air conditioning heat source control system that are extremely simple, cost-effective, highly versatile, and capable of maximizing energy savings. The purpose is to provide a method.

In order to achieve the above object, the present invention provides an air conditioning heat source control system for supplying cold water or hot water from a heat source device to an air conditioner using a circulation pump, in which a set value and a measured value of the temperature difference between the sending and returning water of the air conditioner are determined. The method further includes a control device that variably controls the water supply temperature of the heat source device based on the deviation, and variably controls the pressure of the circulation pump based on information on a control valve provided in a pipe through which the cold water or hot water flows. Features.

The present invention also provides an air conditioning heat source control system that supplies cold water or hot water from a heat source device to an air conditioner using a circulation pump, in which the circulation pump The present invention is characterized by comprising a control device that variably controls the water supply pressure of the heat source device and variably controls the water supply temperature of the heat source device based on information from a control valve provided in a pipe through which the cold water or hot water flows.

In the air conditioning heat source control system according to the present invention, a plurality of the air conditioning devices are provided for the heat source device, and the control device controls the temperature difference between the inlet side portion and the outlet side portion of the heat source device. A measured value of the temperature difference between the sending and returning water may also be obtained.

In the air conditioning heat source control system according to the present invention, a plurality of the air conditioning devices are provided for the heat source device, and the control device controls the temperature of each of the inlet side portion and the outlet side portion of each of the air conditioning devices. The measured value of the temperature difference between the sent and returned water may be determined by weighted averaging the differences.

In the air conditioning heat source control system according to the present invention, a cooling tower may be connected in series upstream of the heat source equipment, and the cooling tower may be used to perform free cooling on the cold water that returns to the heat source equipment.

Furthermore, the present invention provides an air conditioning heat source control method for supplying cold water or hot water from a heat source device to an air conditioner using a circulation pump, in which the heat source device and variably controlling the pressure of the circulation pump based on information from a control valve provided in a pipe through which the cold water or hot water flows.

Furthermore, the present invention provides an air conditioning heat source control method for supplying cold water or hot water from a heat source device to an air conditioning device using a circulating pump, in which the circulating water is determined based on a deviation between a set value and a measured value of a temperature difference between the incoming and outgoing water of the air conditioning device. It is characterized by comprising the steps of: variably controlling the water supply pressure of the pump; and variably controlling the water supply temperature of the heat source device based on information of a control valve provided in a pipe through which the cold water or hot water flows. do.

According to the present invention, it is possible to obtain various excellent effects such as being very simple, having high cost effectiveness and versatility, and being able to maximize energy saving.

1 is a diagram showing the basic configuration of an air conditioning heat source control system according to an embodiment of the present invention. FIG. 3 is a diagram showing trial calculation results of unit energy consumption and energy consumption rate with respect to water supply temperature of heat source equipment in the air conditioning heat source control system according to the embodiment of the present invention. FIG. 7 is a diagram showing trial calculation results of the energy consumption rate with respect to the water supply temperature of the heat source equipment when the load factor changes in the air conditioning heat source control system according to the embodiment of the present invention. In the air conditioning heat source control system according to the embodiment of the present invention, it is a diagram showing the relationship between the water supply temperature for each load factor, the coil outlet water temperature of the air conditioner, and the flow rate ratio. FIG. 3 is a diagram showing the relationship between the water supply temperature and the return water supply temperature difference for each load factor in the air conditioning heat source control system according to the embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the temperature difference of repatriated water and the energy consumption rate for each load factor in the air conditioning heat source control system according to the embodiment of the present invention. A diagram showing the relationship between the temperature difference of return water and the energy consumption rate for each load factor when the COP of the heat source equipment increases from 5.0 to 8.0 in the air conditioning heat source control system according to the embodiment of the present invention. It is. FIG. 3 is a diagram illustrating an example of how to deal with a case where a load deviation occurs in a plurality of air conditioning devices installed with respect to a heat source device in the air conditioning heat source control system according to the embodiment of the present invention. FIG. 6 is a diagram illustrating another example of how to deal with a case where a load deviation occurs in a plurality of air conditioners installed with respect to a heat source device in the air conditioning heat source control system according to the embodiment of the present invention. It is a flow chart which shows the 1st control method of the heat source control system for air conditioning concerning an embodiment of the present invention. It is a flowchart which shows the 2nd control method of the heat source control system for air conditioning based on embodiment of this invention. It is a flowchart which shows the 2nd control method of the heat source control system for air conditioning based on embodiment of this invention. FIG. 2 is a diagram showing a configuration when a free cooling facility is used in combination with an air conditioning heat source control system according to an embodiment of the present invention. 14 is a diagram showing the relationship between the water supply temperature and the return water supply temperature difference in the air conditioning heat source control system when the free cooling equipment of FIG. 13 is used in combination. FIG. In the air conditioning heat source control system when the free cooling equipment of FIG. 13 is used in combination, (a) is a diagram showing the relationship between the outside air wet bulb temperature and the return water temperature difference when the load factor is 50%, and (b) is a diagram showing the relationship between the outside air wet bulb temperature and the return water temperature difference when the load factor is 30%. In the heat source control system for air conditioning when free cooling is used in conjunction with Fig. 13, (a) is a diagram showing the effect of improving the system COP by the optimum return and return water temperature difference when the load factor is 50%, and (b) is a diagram showing the effect of improving the system COP when the load factor is 50%. FIG. 4 is a diagram showing the effect of improving the system COP due to the optimum temperature difference between the forward and return water when the ratio is 30%.

Hereinafter, an air conditioning heat source control system and an air conditioning heat source control method according to embodiments of the present invention will be described with reference to the drawings.

[Overview of air conditioning heat source control system]
First, an overview of an air conditioning heat source control system 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7. In the embodiment of the present invention, a case will be described in which a refrigerator is used as a heat source device and cooling operation is performed by circulating cold water to the air conditioning device on the load side. It can also be applied to cases where heating operation is performed by circulating hot water to air conditioning equipment using other types of heat source equipment.

FIG. 1 is a diagram showing the basic configuration of an air conditioning heat source control system 10 according to an embodiment of the present invention. The air conditioning heat source control system 10 is configured by connecting a refrigerator 11, which is a heat source device, and an air conditioning device 12 via a cold water pipe 13. The air conditioner 12 includes a cold water coil 14 and a blower 15. An air supply duct 16 is connected to the blower 15, and the air supply duct 16 is provided with a VAV (Variable Air Volume) unit 17, a temperature sensor 18 for measuring the air supply outlet temperature, and the like.

In the cold water pipe 13, a primary circulation pump 20 is provided upstream of the refrigerator 11, and a secondary circulation pump 21 is provided between the refrigerator 11 and the cold water coil 14. The cold water pipe 13 is provided with a control valve 22 installed in a general air conditioning system, first to third temperature sensors 23 to 25, and the like. Note that the first temperature sensor 23 measures the temperature of water flowing from the refrigerator 11, the second temperature sensor 24 measures the temperature of cold water flowing to the air conditioner 12, and the third temperature sensor 25 measures the temperature of cold water flowing from the air conditioner 12. Measure the return temperature of cold water.

Further, a temperature sensor 26 for measuring the room temperature is provided in the room to be controlled, and control devices such as the respective devices and sensors are controlled by a control device 30 such as a general-purpose controller.

In the air-conditioning heat source control system 10 according to the embodiment of the present invention having the above-described configuration, the temperature difference between the two-way water supply of cold water sent from the refrigerator 11 to the air-conditioning equipment 12 is a constant value (=designed two-way water supply temperature difference). This method focuses on the fact that if the water supply temperature is controlled to be , the total energy consumption of the refrigerator 11 and the circulation pumps 20 and 21 will be minimized.

FIG. 2 is a diagram showing the trial calculation results of the unit energy consumption (kW) and the energy consumption rate (ratio to the unit energy consumption when the water supply temperature is 7° C.) with respect to the water supply temperature of the refrigerator 11, and the trial calculation conditions at this time. is as follows.

<Estimation conditions>
・System COP of refrigerator 11: 5.0 (2%/℃ efficiency improvement due to increase in water supply temperature)
・Height of circulation pumps 20 and 21: Approximately 20 mAq (power changes with the square of the flow rate)
・Air volume of air conditioner 12 (=load factor): 70%, 50%, 30% (outlet air temperature 16°C)
・Design temperature difference between sending and returning water of chilled water coil 14: 6℃ (7℃→13℃)

As shown in Figure 2, increasing the water supply temperature of the refrigerator 11 requires an increase in the amount of water supplied, so simply increasing the water supply temperature of the refrigerator 11 will reduce the total energy consumption including the pump power. I can't do it. In the trial calculation example shown in FIG. 2, it can be seen that the most energy is saved (optimum water supply temperature) when the water supply temperature is 10 to 11°C.

Figure 3 shows the water flow of the refrigerator 11 when the air volume (=load factor) of the air conditioner 12 changes from 70% (circle mark), 50% (triangle mark), and 30% (square mark) under the above trial calculation conditions. It is a figure showing the trial calculation result of an energy consumption rate with respect to temperature. According to FIG. 3, it can be seen that the optimum water supply temperature of the refrigerator 11 changes depending on the load factor (see (1)→(2)→(3) in the figure).

Figure 4 shows the water supply temperature of the refrigerator 11 and the cold water coil of the air conditioner 12 when the load factor changes from 70% (circle mark), 50% (triangle mark), and 30% (square mark) under the above trial calculation conditions. FIG. 4 shows the relationship between the outlet water temperature and the flow rate ratio of the cold water coil 14. According to FIG. 4, it can be seen that the outlet water temperature of the chilled water coil 14 decreases as the load factor increases or the water supply temperature increases.

Figure 5 is a diagram when the vertical axis is changed from the outlet water temperature in Figure 4 to the return and return water temperature difference, and the load factor is 70% (circle mark), 50% (triangle mark), and 30% (square mark). It shows the relationship between the water supply temperature of the refrigerator 11 and the return water supply temperature difference when the temperature changes. According to FIG. 5, it can be seen that as a characteristic of the chilled water coil 14, as the water supply temperature is increased, the difference in the temperature of the sending water becomes smaller, and on the contrary, as the water temperature is lowered, the difference in the temperature of the sending water becomes larger. The temperature difference between the sending and returning water at the optimum water supply temperature ((1), (2), (3)) for the load factor (70%, 50%, 30%) is concentrated at a difference of approximately 6°C, and this temperature difference is It can be seen that this value is the same as the design temperature difference (6° C.) between the sent and returned water of the chilled water coil 14 under the trial calculation conditions.

Even if heat transfer conditions such as air volume and air temperature change in this way, if the flow rate of the cold water supplied to the chilled water coil 14 of the air conditioning equipment 12 is controlled to a flow rate close to the designed return water temperature difference, the flow rate will be automatically optimized. It can be seen that the temperature converges around the water supply temperature.

In addition, in Figure 6, under the same conditions as Figure 5, the X-axis is the temperature difference between the sending and returning water, and the Y-axis is the energy consumption rate, and the load factor is 70% (circle mark), 50% (triangle mark), and 30% ( (square mark) shows the relationship between the outgoing and returning water temperature difference and the energy consumption rate when the temperature changes. According to Fig. 6, at any load rate, the waveform becomes a pot-bottom type in which the slope decreases around 6°C, which is the optimum temperature difference between the sending water and the sending water. Even if there is a deviation, the energy saving performance will not be significantly reduced.

Furthermore, FIG. 7 shows the air volume (=load The graph shows the relationship between the temperature difference of the sent water and the energy consumption rate when the rate) changes from 70% (circle mark), 50% (triangle mark), and 30% (square mark). According to FIG. 7, even if the performance of the refrigerator 11 changes greatly, the value of the optimal return water temperature difference hardly changes, and even if the efficiency of the refrigerator 11 changes, the optimal return water temperature difference remains constant. It turns out that there is no problem.

In the above estimation, it is assumed that the efficiency improvement rate of the refrigerator 11 due to an increase in water supply temperature is a constant rate, but in reality, the efficiency improvement rate varies slightly depending on the type of refrigerator 11, the load factor, or the outside air condition. Further, depending on the load factor on the air conditioner 12 side, there tends to be a slight deviation in the optimum temperature difference between the sending and returning water. Therefore, for example, the optimal value of the temperature difference of the returning water may be calculated and varied using the load factor, outside air temperature, outside air wet bulb temperature, outside air enthalpy, etc. as parameters.

[First control method of air conditioning heat source control system]
Next, a first control method for the air conditioning heat source control system 10 according to the embodiment of the present invention will be described with reference to FIG. 1 and FIGS. 8 to 10.

In the air conditioning heat source control system 10 according to the embodiment of the present invention, as a first control method, the control device 30 sets the set value S of the temperature difference between the outward and return water to the refrigerator 11, the second temperature sensor 24, and the third temperature sensor 24. Based on the deviation from the measured value M calculated from the temperature sensor 25, the water supply temperature of the refrigerator 11 is variably controlled proportionally or stepwise.

At this time, the control device 30 can control the amount of cold water flowing through the cold water pipe 13 by controlling the opening degree of the control valve 22 based on changes in the water supply temperature, air supply outlet temperature, and room temperature of the refrigerator 11. It becomes necessary. As a result, pressure fluctuations occur in the cold water pipe 13, so it is necessary to control the water supply pressure of the secondary circulation pump 21. Examples of control methods include, for example, constant return pressure INV control, constant terminal pressure INV control, A general pressure control method such as estimated terminal pressure constant INV control can be applied as is. It is also possible to apply the above pressure control method to a method of varying the set pressure value using a two-way valve with a flow rate measurement function.

Although FIG. 1 above shows an example in which the refrigerator 11 and the air conditioner 12 are installed one-to-one, in reality, as shown in FIGS. 8 and 9, multiple Air conditioners 12a, 12b, and 12c are often installed. In such a case, a considerable load deviation occurs between the air conditioners 12a, 12b, and 12c, and a deviation also occurs in the temperature difference between the sent and returned water between the air conditioners 12a, 12b, and 12c.

Therefore, as shown in FIG. 8, a fourth temperature sensor 27 is installed in the collecting pipe around the refrigerator 11, and the control device 30 detects the temperature difference between the first temperature sensor 23 and the fourth temperature sensor 27. The water temperature of the refrigerator 11 can be variably controlled by taking the measured value M of the temperature difference between the going and returning water and finding the deviation between this measured value M and the set value S of the temperature difference between the going and returning water.

Alternatively, the control device 30 may detect the temperature difference between the second temperature sensors 24a to 24c and the third temperature sensors 25a to 25c provided at the entrance/exit side portions of the cold water coils 14a to 14c of each of the air conditioners 12a to 12c. The weighted average temperature difference calculated from the amount of chilled water in the chilled water coils 14a to 14c using the following equation (1) is defined as the measured value M of the temperature difference between the outward and return water, and the deviation between this measured value M and the set value S of the temperature difference between the outward and return water is calculated as follows: By determining the temperature, the water temperature of the refrigerator 11 may be variably controlled.
Weighted average temperature difference=Σ(Δti×Qi)÷ΣQi (1)
Here, Qi: water amount, Δti: temperature difference

Alternatively, the control device 30 may detect the temperature difference between the second temperature sensors 24a to 24c and the third temperature sensors 25a to 25c provided at the entrance/exit side portions of the cold water coils 14a to 14c of each of the air conditioners 12a to 12c. The weighted average temperature difference calculated by the following equation (2) from the opening degrees of the control valves 22a to 22c is defined as the measured value M of the temperature difference between the outward and return water, and the deviation between this measured value M and the set value S of the temperature difference between the outward and return water is calculated. By determining the temperature, the water temperature of the refrigerator 11 may be variably controlled.
Weighted average temperature difference=Σ(Δti×Vi)÷ΣVi (2)
Here, Vi: control valve opening degree

If the load form is similar throughout the building to be controlled as shown in FIG. 8, the above method can be used to control the load without any problem. If a system with an extremely large load deviation occurs, it may become impossible to handle the load at the water supply temperatures determined by all air conditioners in the same system.

For example, while the set value S of the temperature difference between the incoming and outgoing water is 6°C, the measured value M is extremely small at 3°C or less, or the opening degree of the control valve 22c is close to fully open, for example, 95% or more. If the control device 30 detects that the air supply outlet temperature or the room temperature does not satisfy the control set values, it may correct the temperature by lowering the water supply temperature by 1° C. or the like.

In addition, from the aspect of air conditioning environmental quality, if the water supply temperature is increased, the dehumidification capacity decreases and the indoor humidity increases. good.

Next, a first control method for the air conditioning heat source control system 10 according to the embodiment of the present invention will be described in detail with reference to the flowcharts of FIGS. 1, 8, 9, and 10.

First, as shown in step 11 (S11), the control device 30 uses the above formula (1 ) or (2) to calculate the weighted average temperature difference.

In the next step 12 (S12), the control device 30 determines whether the dew point temperature measured in the room to be controlled is less than a predetermined temperature (for example, 18 DP° C.). As a result, if the control device 30 determines that the indoor dew point temperature is lower than the predetermined temperature (for example, 18DP°C) (in the case of Yes), the control device 30 proceeds to step 13 (S13), and controls the control valves 22a to 22c. Based on the opening degree information, it is determined whether there are any control valves 22a to 22c with an opening degree of 100%. As a result, if the control device 30 determines that there are no control valves 22a to 22c with an opening degree of 100% (in the case of Yes), the process proceeds to step 14 (S14).

On the other hand, if the control device 30 determines that the indoor dew point temperature is not lower than the predetermined temperature (for example, 18DP°C) in step 12 (S12) (No), and in step 13 (S13), the controller 30 If it is determined that the temperature control valves 22a to 22c exist (in the case of No), the process proceeds to step 17 (S17), and after lowering the water supply temperature of the refrigerator 11 by a predetermined temperature (t°C), the control is terminated. .

In step 14 (S14), the control device 30 determines whether the deviation obtained by subtracting the set value S of the outgoing water temperature difference from the weighted average measured value M of the outgoing water temperature difference calculated in step 11 (S11) above exceeds 1°C. judge whether As a result, if the deviation obtained by subtracting the set value S of the outgoing water temperature difference from the measured value M of the weighted average outgoing water temperature difference exceeds 1°C (in the case of Yes), the control device 30 performs step 15 (S15). After increasing the water supply temperature of the refrigerator 11 by a predetermined temperature (t° C.), the control ends.

On the other hand, if the deviation obtained by subtracting the set value S of the outgoing water temperature difference from the measured value M of the weighted average temperature difference in step 14 (S14) does not exceed 1°C (in the case of No), the control device 30 , proceed to step 16 (S16).

In step 16 (S16), the control device 30 determines whether the deviation obtained by subtracting the set value S of the outgoing water temperature difference from the measured value M of the weighted average temperature difference calculated in the above step 11 (S11) is less than 1°C. do. As a result, if the control device 30 determines that the deviation obtained by subtracting the set value S of the outgoing water temperature difference from the measured value M of the weighted average temperature difference is less than 1°C (in the case of Yes), step 17 ( Proceeding to S17), the water supply temperature is lowered by a predetermined temperature (t° C.), and then the control is ended.

On the other hand, if the control device 30 determines in step 16 (S16) that the deviation obtained by subtracting the set value S of the outgoing water temperature difference from the measured value M of the weighted average temperature difference is not less than 1°C (in the case of No), ends control.

Note that the predetermined temperature (t° C.), which is the amount of change in the water supply temperature in step 15 (S15) and step 17 (S17), may be a fixed value or may be a value proportional to the amount of deviation.

[Second control method of air conditioning heat source control system]
Next, a second control method for the air conditioning heat source control system 10 according to the embodiment of the present invention will be described with reference to FIGS. 1, 8, 9, and 11 to 16.

In the air-conditioning heat source control system 10 according to the embodiment of the present invention, as a second control method, the control device 30 sets a set value S of the temperature difference between the outward and return water of the air conditioner 12, the second temperature sensor 24, and the third temperature sensor 24. Based on the deviation from the measured value M calculated from the temperature sensor 25, the water supply pressure of the circulation pumps 20 and 21 is variably controlled.

In other words, if the water temperature of the refrigerator 11 is increased excessively, the amount of water sent will be excessive and the energy consumption will increase. Therefore, by adjusting the water pressure of the circulation pump by the temperature difference between the outward and returning water, the temperature difference between the outward and returning water can be reduced. A feature of the second control method is to suppress excessive flow by adjusting the water supply amount to a constant value.

In this case, the control device 30 variably controls the water supply temperature of the refrigerator 11 based on the opening degree information of the control valves 22a to 22c. For example, if the control device 30 determines that at least one of the control valves 22a to 22c is in an insufficient state (opening degree of 95% or more) based on the opening degree information of the control valves 22a to 22c, the control device 30 lowers the water supply temperature by 1° C. If it is determined that all the control valves 22a to 22c are in an excessive state (opening of 80% or less), the water supply temperature is raised by 1°C, and each control valve 22a to 22c is set to an appropriate state (opening of 80 to 95%). %) and an excessive state coexist, the water supply temperature is controlled to be maintained. By controlling in this way, it is possible to avoid a capacity shortage due to an increase in the water supply temperature, and also to maintain the water supply temperature as high as possible and the control valve in a state close to fully open.

In the second control method, the pressure before and after the circulation pump 21 is measured, and the pressure before and after the circulation pump 21, which increases or decreases by opening and closing the control valves 22a to 22c of the air conditioners 12a to 12c, is maintained at a constant value. Energy saving is achieved by controlling the rotation speed of the motor of the circulation pump 21, and by variably controlling the set value of this pressure, it is possible to increase or decrease the amount of water fed.

For example, if the water supply pressure is lowered when the temperature difference between the outward and return water supply is smaller than the set value, the amount of water supplied decreases and the amount of heat dissipated from the air conditioners 12a to 12c decreases, so the control valves 22a to 22c are opened. If the heat radiation capacity of the air conditioners 12a to 12c is insufficient even when the control valves 22a to 22c are fully open, the control device 30, based on the opening degree information of the control valves 22a to 22c, as described above, Control to lower the water temperature.

In this way, by repeating mutual control in some cases until the temperature difference between the going and returning water reaches the target value, the temperature difference between the going and returning water can be converged to the set temperature difference, and the water temperature can be controlled to the optimum temperature. and water supply pressure can be controlled at the same time.

As shown in FIGS. 8 and 9, when a plurality of air conditioners 12a, 12b, 12c are installed for one system of refrigerator 11, the difference in temperature of the sent water is determined by the above-described first control method. Similarly, it can be determined by the temperature sensors 23 and 27 provided in the cold water pipes around the refrigerator 11 or by the weighted average temperature difference.

Next, a second control method for the air conditioning heat source control system 10 according to the embodiment of the present invention will be explained in detail with reference to the flowcharts of FIGS. 1, 8, 9, and 11 and 12. .

First, regarding the water supply temperature control, as shown in step 21 (S21) in FIG. do. As a result, if the control device 30 determines that the indoor dew point temperature is less than the predetermined temperature (for example, 18 DP° C.) (in the case of Yes), the control device 30 proceeds to the next step 22 (S22).

On the other hand, if the control device 30 determines in step 21 (S21) that the dew point temperature measured in the room to be controlled is not lower than the predetermined temperature (for example, 18DP°C) (in the case of No), in step 25 ( Proceeding to S25), the water supply temperature of the refrigerator 11 is increased by 1° C., and the control is ended.

In the next step 22 (S22), the control device 30 determines the overall state of the control valves 22a to 22c based on the opening degree information of each control valve 22a to 22c. Specifically, the control device 30 determines whether at least one of the control valves 22a to 22c is in an "insufficient state 1" (for example, opening degree is 95% or more), or if each control valve 22a to 22c is in an "appropriate state". It is determined whether all control valves 22a to 22c are in "state 2" (for example, opening degree is 80 to 95%) or whether all control valves 22a to 22c are in "excessive state 3" (for example, opening degree is 80% or less).

As a result, if the control device 30 determines that the overall state of at least one of the control valves 22a to 22c is "insufficient state 1" (in the case of Yes), the control device 30 proceeds to the next step 23 (S23). , lower the water temperature of the refrigerator 11 by 1°C.

On the other hand, if the control device 30 determines in step 22 (S22) that the overall state of all the control valves 22a to 22c is not "insufficient state 1" (in the case of NO), the control device 30 proceeds to step 24 (S24). .

In step 24 (S24), the control device 30 determines whether all the control valves 22a to 22c are in "excessive state 3" (for example, opening degree is 80% or less). As a result, if the control device 30 determines that the overall state of all the control valves 22a to 22c is "excessive state 3" (in the case of Yes), the control device 30 proceeds to step 25 (S25), and the refrigerator 11 Raise the water temperature by 1℃.

On the other hand, if the control device 30 determines in step 24 (S24) that the overall state of any of the control valves 22a to 22c is not "excessive state 3" (in the case of NO), it ends the control.

Next, regarding pump pressure control, as shown in step 31 (S31) in FIG. 12, the control device 30 uses the above formula (1) based on the measured values of the water supply temperature and return water temperature for each air conditioner 12a to 12c. Alternatively, calculate the weighted average outgoing water temperature difference using (2).

In the next step 32 (S32), the control device 30 determines that the deviation obtained by subtracting the measured value M of the weighted average return water temperature difference calculated in step 31 (S31) from the set value S of the return water temperature difference is 1°C. Determine whether it exceeds. As a result, if the deviation obtained by subtracting the set value M of the weighted average outgoing water temperature difference from the set value S of the outgoing water temperature difference exceeds 1°C (in the case of Yes), the control device 30 performs step 33 (S33). After the pressure setting value is lowered by 10 kPa, the control is terminated.

On the other hand, if the deviation obtained by subtracting the measured value M of the outbound and return water temperature difference from the set value S of the outbound and return water temperature difference in step 32 (S32) does not exceed 1°C (in the case of No), the control device 30 The process advances to step 34 (S34).

In step 34 (S34), the control device 30 determines whether the deviation obtained by subtracting the measured value M of the weighted average outgoing water temperature difference calculated in step 31 (S31) from the set value S of the outgoing water temperature difference is less than 1°C. to judge. As a result, if the control device 30 determines that the deviation obtained by subtracting the measured value M of the outgoing water temperature difference from the set value S of the weighted average temperature difference is less than 1°C (in the case of Yes), step 35 ( Proceeding to S35), the predetermined pressure value is increased by 10 kPa, and then the control is ended.

On the other hand, if the control device 30 determines in step 34 (S34) that the deviation obtained by subtracting the measured value M of the outgoing water temperature difference from the set value S of the weighted average temperature difference is not less than 1°C (in the case of No), ends control.

Note that the predetermined pressure value (10 kPa), which is the amount of change in the pressure setting value in step 33 (S33) and step 35 (S35), may be a fixed value or may be a value proportional to the deviation amount.
[Application example of heat source control system for air conditioning]

Next, as an application example of the air conditioning heat source control system 10 according to the embodiment of the present invention, an air conditioning heat source control system 50 that uses free cooling equipment will be described with reference to FIGS. 13 to 16.

As shown in FIG. 13, this air conditioning heat source control system 50 connects a cooling tower 53 in series with a heat source 11 in a system that uses chilled water in a relatively high temperature range as a heat medium, such as a radiant panel 51 or a sensible heat air conditioner 52. This is a system in which the returned cold water is cooled in the cooling tower 53 and then cooled to a predetermined temperature by the heat source 11 on the downstream side.

In this way, in the air conditioning heat source control system 50, which can be used in conjunction with a cooling system that is dramatically more efficient depending on the outside air conditions, etc., by purposely setting the temperature difference between the incoming and outgoing water to be small, it is possible to utilize highly efficient heat sources such as free cooling equipment. It can also be promoted.

As shown in FIG. 14, when the temperature difference between the sent and returned water is reduced to about 1/2 of the temperature difference between the sent and sent water when the normal air conditioning heat source control system 10 is used, the temperature range of the sent and sent water shifts to the high temperature side. In this case, even if the wet bulb temperature condition is such that it is impossible to operate the free cooling equipment in the normal temperature range of the sending water and the return water, the free cooling equipment can be operated as the temperature range of the returning water changes to a higher temperature. It becomes possible. Since the cooling efficiency during operation of the free cooling equipment is several to several tens of times higher than the cooling efficiency of the refrigerator 11, it is possible to sufficiently absorb an increase in the conveying power. In this way, by making the temperature difference between the sent and returned water variable depending on the conditions, it is possible to extend the operating period of the highly efficient cooling system, and it is possible to improve the energy saving effect.

In the case of the air conditioning heat source control system 50 that uses free cooling equipment, the efficiency of the system 50 (system COP) changes greatly depending on the outside air wet bulb temperature and the load factor of the air conditioning equipment. Therefore, as shown in FIGS. 15(a) and 15(b), a more optimal return and return water temperature difference (linear) is determined for each load factor of air conditioning equipment and each outside air wet bulb temperature, and It is preferable to variably control the setting value of the optimum forward and return water temperature difference depending on the temperature. Thereby, as shown in FIGS. 16(a) and 16(b), efficiency (system COP) can be improved and the energy saving effect can be further enhanced.

[Effects of the air conditioning heat source control system according to the embodiment of the present invention]
As described above, the air conditioning heat source control system 10, 50 according to the present invention uses normal control equipment such as a temperature sensor and a general-purpose controller installed in a general air conditioning system to adjust the water temperature based on the temperature difference between the outward and return water. Variable control can be performed, and there is no need to introduce a large number of measuring instruments or arithmetic devices, nor do detailed design or software development in advance, so it is highly cost-effective and can improve versatility.

In addition, by variably controlling the water supply temperature based on the opening information of the control valve, and variably controlling the water supply pressure based on the difference in the temperature of the returning and returning water, both the water supply temperature (VWT) and flow rate (VWV) can be simultaneously and optimally controlled. Since it can be controlled, it is possible to maximize the energy saving effect.

Note that the above description of the embodiments of the present invention describes preferred embodiments of the air conditioning heat source control system according to the present invention, and therefore various technically preferable limitations may be attached. However, the technical scope of the present invention is not limited to these embodiments unless there is a description that specifically limits the present invention.

10 Air conditioning heat source control system 11 Refrigerator (heat source equipment)
12 Air conditioning equipment 20 Primary circulation pump 21 Secondary circulation pump 30 Control device 50 Air conditioning heat source control system 53 Cooling tower

Claims (5)

In an air conditioning heat source control system that supplies cold water or hot water from a heat source device to an air conditioner using a circulation pump,
From a set value that is a designed return water temperature difference of the cold water or hot water sent from the heat source device to the air conditioner, and the temperature measured by the temperature sensor to the air conditioner and the return temperature from the air conditioner. The water supply pressure of the circulation pump is variably controlled based on the deviation between the calculated measured value of the temperature difference between the sent and returned water, and the heat source equipment is controlled based on information on a control valve provided in a pipe through which the cold water or hot water flows 1. A heat source control system for air conditioning, comprising a control device that variably controls the water temperature of the air conditioner. A plurality of the air conditioning devices are provided for the heat source device, and the control device determines the measured value of the temperature difference between the incoming and outgoing water based on the temperature difference between an inlet side portion and an outlet side portion of the heat source device . The air conditioning heat source control system described in . A plurality of the air conditioning devices are provided for the heat source device, and the control device determines the temperature difference between the incoming and outgoing water by weighted averaging the temperature differences between the inlet side portion and the outlet side portion of each of the air conditioners. The air conditioning heat source control system according to claim 1, wherein the measured value of . 2. The air conditioning heat source control system according to claim 1 , wherein a cooling tower is connected in series upstream of the heat source device, and the cooling tower is used to perform free cooling on cold water that returns to the heat source device. In an air conditioning heat source control method for supplying cold water or hot water from a heat source device to an air conditioner using a circulation pump,
From a set value that is a designed return water temperature difference of the cold water or hot water sent from the heat source device to the air conditioner, and the temperature measured by the temperature sensor to the air conditioner and the return temperature from the air conditioner. variably controlling the water supply pressure of the circulation pump based on the deviation between the calculated measured value of the temperature difference between the sent and returned water;
variably controlling the water supply temperature of the heat source device based on information on a control valve provided in a pipe through which the cold water or hot water flows;
A heat source control method for air conditioning, comprising:

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