JP2021050860A - Air-conditioning system using snow and ice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce energy consumption at the time of combined operation of an indirect outside air air conditioner and a snow ice cold water air conditioner in an air conditioner using snow and ice. A liquid-liquid heat exchanger 31 is located on a brine pipe 16 in an indirect outside air cooler 10, and an inside air heat exchanger 11 exchanges heat between the air return from the air conditioning target space and the brine. At a position higher than the position where the return air is cooled, the brine pump 15 circulates in the brine pipe 16 and the snow ice pump 23 circulates in the chilled water pipe 24 in the snow ice cold water cooler 20. The brine is cooled by the cold water by exchanging heat with the cold water. After the brine pump 15 is stopped, the indirect outside air cooler 10 circulates the brine in the brine pipe 16 by the thermal convection of the brine generated by cooling the brine with cold water by heat exchange by the liquid-liquid heat exchanger 31. Let me. [Selection diagram] Fig. 2

Description

The present invention relates to an air conditioning system that utilizes snow and ice.

In recent years, in snowy areas and the like, snowy mountains have been created from snowfall in winter, and a snow-ice-using air conditioner that utilizes the cold heat of the snowy mountains has been used except in winter.

For example, Patent Document 1 proposes a snow-ice-using air-conditioning system in which such a snow-ice-using air conditioner and an indirect outside air-cooling machine are used in combination to cool an air-conditioned space with energy efficiency.

Here, FIG. 1 will be described. FIG. 1 is a configuration diagram of a conventional example of an air conditioning system using snow and ice. This snow and ice air conditioning system is proposed in Patent Document 1.

This snow-ice utilization air-conditioning system realizes cooling of the air-conditioning target space by using the indirect outside air cooler 10 and the snow-ice cold water air conditioner 20 in combination.

In FIG. 1, the configuration related to the indirect outside air cooler 10 is an inside air heat exchanger 11, an inside air fan 12, an outside air heat exchanger 13, an outside air fan 14, a brine pump 15, and a brine pipe 16. An inside air heat exchanger 11 and an inside air fan 12 are provided in the indoor unit 1 provided in the building. An outside air heat exchanger 13 and an outside air fan 14 are provided inside an outdoor unit 2 provided outside the building.

The configuration of the snow / ice cold water air conditioner 20 is a snow ice (snow mountain) 21, a water melting tank 22, a snow ice pump 23, and a cold water pipe 24.

A liquid-liquid heat exchanger 31 is provided as a configuration for heat exchange between the indirect outside air cooler 10 and the snow ice cold water cooler 20. In the liquid-liquid heat exchanger 31, heat exchange between liquids (here, brine and cold water) is performed.

In the indirect outside air cooler 10, while the brine pump 15 is in operation, brine, which is a refrigerant, circulates between the inside air heat exchanger 11 and the outside air heat exchanger 13 via the brine pipe 16. Then, the return air (RA) is taken into the indoor unit 1 by the inside air fan 12, and is passed through the inside air heat exchanger 11 to exchange heat with the brine. As a result, the return air (RA) is cooled to be cooled, and this is supplied to the cooling target space as the supply air (SA).

The cooling target space is, for example, a server room or the like, and the temperature of the supply air (SA) rises by cooling the server device or the like to become the above-mentioned return air (RA). Further, the brine is returned to the outside air heat exchanger 13 after the temperature rises due to heat exchange with the return air (RA) in the inside air heat exchanger 11, and heat exchange with the outside air (OA) in the outside air heat exchanger 13. Is done.

During operation, the outside air fan 14 takes in outside air (OA) into the outdoor unit 2, passes it through the outside air heat exchanger 13 to exchange heat with brine, and then goes out of the outdoor unit 2 as exhaust gas (EA). Discharge.

In the snow / ice cold water air conditioner 20, when the snow / ice pump 23 is in operation, water circulates in the cold water pipe 24. The chilled water pipe 24 is provided so as to pass through the inside of the water melting tank 22. Water (melted snow) melted from snow ice (snow mountain) 21 passes through / stores in the water melting tank 22. This water is cooled in the meltwater tank 22 by heat exchange with the melted snow water. That is, the cold water cooled by the cold heat of the snow ice (snow mountain) 21 circulates in the cold water pipe 24.

The cold water pipe 24 and the brine pipe 16 pass through the liquid-liquid heat exchanger 31, and when the brine pump 15 and the snow ice pump 23 are in operation, the liquid-liquid heat exchanger 31 has brine and cold water. It is configured to exchange heat with. The liquid-liquid heat exchanger 31 cools the brine with cold water.

The snow / ice utilization air conditioning system is further provided with a control device 40 that controls the entire snow / ice utilization air conditioning system. Further, a temperature sensor 3 for measuring the temperature of the supply air (SA) is provided.

The control device 40 is connected to a temperature sensor 3, an inside air fan 12, an outside air fan 14, a brine pump 15, a snow ice pump 23, etc. via a communication line (not shown), and controls these via this communication line. I do. That is, for example, the control device 40 executes the start / stop control of the inside air fan 12 and the outside air fan 14 and the control of the fan rotation speed via a communication line (not shown). Alternatively, the control device 40 executes, for example, the start / stop control of the brine pump 15 and the snow ice pump 23 and the control of the pump rotation speed via a communication line (not shown).

The control device 40 stores the set temperature for the supply air (SA) in a built-in memory (not shown). The control device 40 acquires the measured value of the temperature of the supply air (SA) by the temperature sensor 3 at any time via a communication line (not shown), and based on the measured value, the set temperature, and the like, each of the above components. (12, 14, 15, 23) is controlled. This control is basically a control for maintaining the temperature of the supply air (SA) at a set temperature.

In this snow-ice utilization air-conditioning system, when the temperature of the supply air (SA) cannot be maintained at the set temperature by the independent operation of the indirect outside air conditioner 10, the indirect outside air conditioner 10 and the snow ice cold water air conditioner 20 are operated in combination. Do. During this combined operation, the control device 40 constantly operates the brine pump 15 at a constant rotation speed, changes the rotation speed of the snow ice pump 23 and the outside air fan 14, and sends the temperature of the brine to the inside air heat exchanger 11. The temperature of the supply air (SA) is controlled by changing.

Japanese Patent No. 6432641

As described above, in the snow and ice utilization air conditioner system described in Patent Document 1, the brine pump 15 is always operated when the indirect outside air cooler 10 and the snow and ice cold water cooler 20 are operated in combination. Therefore, energy (electric power) is consumed by the brine pump 15 during the combined operation.

In one aspect, it is an object of the present invention to reduce energy consumption during combined operation of an indirect outside air conditioner and a snow ice cold water air conditioner in a snow ice utilization air conditioning system.

According to one embodiment, the snow and ice utilization air conditioning system includes an indirect outside air cooler, a snow and ice cold water cooler, and a third heat exchanger.

The indirect outside air cooler is a first pipe that is a circulation path through which the refrigerant circulates, a refrigerant pump that circulates the refrigerant in the first pipe, and a first of the return air and the refrigerant that are the return air from the space to be air-conditioned. It has a first heat exchanger that exchanges heat to cool the return air, and a second heat exchanger that exchanges heat between the outside air and the refrigerant to dissipate heat from the refrigerant.

The snow-ice chilled water conditioner has a second pipe that is a circulation path for chilled water and a snow-ice pump that circulates cold water in the second pipe. Cooling.

The third heat exchanger cools the refrigerant by performing a third heat exchange between the refrigerant in the first pipe and the cold water in the second pipe, and is a position on the first pipe and is the first. A third heat exchange is performed at a position higher than the position where the heat exchange is performed, and the refrigerant is cooled with cold water.

After the operating refrigerant pump is stopped, the indirect outside air cooler circulates the refrigerant in the first pipe by the thermal convection of the refrigerant generated by cooling the refrigerant with cold water by the third heat exchange.

In one aspect, it is possible to reduce the energy consumption during the combined operation of the indirect outside air conditioner and the snow / ice chilled water air conditioner in the snow / ice utilization air conditioning system.

It is a block diagram of a conventional example of an air-conditioning system using snow and ice. It is a block diagram of the snow-ice utilization air-conditioning system of embodiment. It is a flowchart which illustrates the processing operation at the time of normal operation of the control device of the snow-ice utilization air-conditioning system of embodiment. It is a figure which shows the operation example at the time of the normal operation of each component of the snow-ice utilization air-conditioning system of embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 2 is a configuration diagram of an air conditioning system using snow and ice according to the embodiment. In FIG. 2, the same components as those in FIG. 1 are designated by the same reference numerals.

In the snow and ice air conditioning system of FIG. 2, a liquid-liquid heat exchanger 31 and an outdoor unit 2 of the indirect outdoor air conditioner 10 are installed on the roof of a building in which the indoor unit 1 of the indirect outdoor air conditioner 10 is installed. It has the characteristic that it is. More specifically, although it is not clear in FIG. 2, the liquid-liquid heat exchanger 31 is installed at the position where the height in the vertical direction is the highest on the path of the brine pipe 16, and the height in the vertical direction is high. The internal air heat exchanger 11 is installed at the lowest position. That is, the heat exchange between the brine and the cold water by the liquid-liquid heat exchanger 31 is higher than the position on the brine pipe 16 where the heat exchange between the brine and the return air (RA) by the internal air heat exchanger 11 is performed. It is configured to be done in.

In the snow-ice utilization air conditioning system of FIG. 2, the outside air heat exchanger 13 is also installed on the path of the brine pipe 16 at a position higher in the vertical direction than the installation position of the inside air heat exchanger 11. Therefore, the heat exchange between the brine and the outside air (OA) by the outside air heat exchanger 13 is also higher than the position on the brine pipe 16 where the heat exchange between the brine and the return air (RA) is performed by the inside air heat exchanger 11. It is configured to be done in position.

The snow and ice air conditioning system of FIG. 2 will be described in more detail.

In FIG. 2, the configuration related to the indirect outside air cooler 10 is an inside air heat exchanger 11, an inside air fan 12, an outside air heat exchanger 13, an outside air fan 14, a brine pump 15, and a brine pipe 16. An inside air heat exchanger 11 and an inside air fan 12 are provided in the indoor unit 1 provided in the building. Further, an outside air heat exchanger 13, an outside air fan 14, and a brine pump 15 are provided in the outdoor unit 2 provided on the roof of the building.

The configuration of the snow / ice cold water air conditioner 20 is a snow ice (snow mountain) 21, a water melting tank 22, a snow ice pump 23, and a cold water pipe 24.

In the indirect outside air cooler 10, when the brine pump 15 is operated, brine, which is a refrigerant, circulates between the inside air heat exchanger 11 and the outside air heat exchanger 13 via the brine pipe 16. In FIG. 2, the direction of circulation of the brine on the brine pipe 16 when the brine pump 15 is in operation is indicated by an arrow. Then, even if the return air (RA) is taken into the indoor unit 1 and passed through the inside air heat exchanger 11 by the inside air fan 12, heat exchange (first heat exchange) with the brine is performed. As a result, the return air (RA) is cooled to be cooled, and this is supplied to the cooling target space as the supply air (SA). However, if the temperature of the brine becomes higher than the temperature of the return air (RA), the return air (RA) cannot be cooled.

The cooling target space in the building is, for example, a server room of a data center or the like, and the temperature of the supply air (SA) rises by cooling the server device or the like, resulting in the return air (RA) described above. Further, the brine is returned to the outside air heat exchanger 13 after the temperature rises due to heat exchange with the return air (RA) in the inside air heat exchanger 11, and heat exchange with the outside air (OA) in the outside air heat exchanger 13 (No. 1). 2 heat exchange) is performed.

During operation, the outside air fan 14 takes in outside air (OA) into the outdoor unit 2 and exchanges heat with the brine by passing it through the outside air heat exchanger 13, and then, as exhaust gas (EA), outside the outdoor unit 2. Discharge to.

In the snow / ice cold water air conditioner 20, when the snow / ice pump 23 is operated, cold water circulates in the cold water pipe 24. In FIG. 2, the direction of circulation of cold water on the cold water pipe 24 when the snow and ice pump 23 is operating is indicated by an arrow. The chilled water pipe 24 is provided so as to pass through the inside of the water melting tank 22. Water (melted snow) melted from snow ice (snow mountain) 21 passes through / stores in the water melting tank 22. As a result, the water circulating in the cold water pipe 24 is cooled in the water melting tank 22 by heat exchange with the thawed water. That is, the water is cooled by the cold heat of the snow ice (snow mountain) 21 to become cold water. Not limited to this example, for example, the thaw water itself may flow in the cold water pipe 24 as cold water.

A brine pipe 16 which is a first pipe and a chilled water pipe 24 which is a second pipe pass through the liquid-liquid heat exchanger 31, and brine and cold water circulate in the brine pipe 16 and the chilled water pipe 24, respectively. In this case, the liquid-liquid heat exchanger 31 is configured to perform heat exchange (third heat exchange) between the brine and cold water. The liquid-liquid heat exchanger 31 cools the brine with cold water.

However, the liquid-liquid heat exchanger 31 is provided at a portion of the annular brine pipe 16 where the brine flows from the inside air heat exchanger 11 to the outside air heat exchanger 13. Therefore, the liquid-liquid heat exchanger 31 is after heat exchange with the return air (RA) by the inside air heat exchanger 11 for the brine, and with the outside air (OA) by the outside air heat exchanger 13 for the brine. Before the heat exchange of the above, the heat exchange between the cold water and the brine is performed.

The snow / ice utilization air conditioning system is further provided with a control device 40 that controls the entire snow / ice utilization air conditioning system. Further, a temperature sensor 3 is provided as a temperature measuring means for measuring the temperature of the supply air (SA).

The control device 40 is connected to a temperature sensor 3, an inside air fan 12, an outside air fan 14, a brine pump 15, a snow ice pump 23, etc. via a communication line (not shown), and controls these via this communication line. I do. That is, for example, the control device 40 executes the start / stop control of the inside air fan 12 and the outside air fan 14 and the control of the fan rotation speed via a communication line (not shown). Alternatively, the control device 40 executes, for example, the start / stop control of the brine pump 15 and the snow ice pump 23 and the control of the pump rotation speed via a communication line (not shown).

The control device 40 stores the set temperature for the air supply (SA) in its built-in memory. The control device 40 acquires the measured value of the temperature of the supply air (SA) by the temperature sensor 3 at any time via a communication line (not shown), and based on the measured value, the set temperature, and the like, the above-mentioned various configurations ( 12, 14, 15, 23) are controlled. This control is basically a control for maintaining the temperature of the supply air (SA) at a set temperature.

The control device 40 includes, for example, a storage device such as a CPU or memory (not shown), a communication interface, or the like, and a predetermined application program is stored in the storage device in advance. By executing this application program, the CPU performs the above-mentioned various controls or performs the process of FIG. 3 described later to maintain the temperature of the supply air (SA) at the temperature set value.

Hereinafter, an operation example of the snow and ice utilization air conditioning system shown in FIG. 2 will be described separately for normal operation and power saving operation.
[1: Operation example during normal operation]
An operation example of the snow and ice air-conditioning system shown in FIG. 2 during normal operation will be described with reference to FIGS. 3 and 4.

FIG. 3 is a flowchart illustrating the processing operation of the control device 40 in the snow and ice utilization air conditioning system of the embodiment. However, this flowchart shows a processing operation assuming a case where the temperature (outside air temperature) of the outside air (OA) rises from a very low state.

FIG. 4 shows an operation example of each component. This operation example is realized by the control device 40 controlling each component in accordance with the process of FIG.

In FIG. 4, the horizontal axis is, for example, the outside air temperature when the temperature of the return air (RA) is constant. That is, in FIG. 4, the outside air temperature is very low at the left end, and the outside air temperature becomes higher toward the right. Therefore, the snow-ice utilization air-conditioning system shown in FIG. 2 corresponds to the independent operation of the indirect outside air conditioner 10 when the outside air temperature is low, and the combined operation of the indirect outside air conditioner 10 and the snow ice cooling water air conditioner 20 when the outside air temperature is high. What to do can be seen in FIG.

The control device 40 controls the snow and ice utilization air conditioning system using any of the various operation control modes shown in FIG. This control is based on the temperature of the supply air (SA) and the like, but as a result, the operation control is performed in the mode according to the current outside air temperature.

In the example shown in FIG. 4, the operation control mode includes a mode “A0-1”, a mode “A0-2”, a mode A1, a mode A2, and a mode B1 in order from the one having the lowest outside air temperature. That is, the control is performed in the operation control mode according to the outside air temperature. For example, when the outside air temperature is very low, the control is performed in the mode "A0-1".

However, the temperature of the supply air (SA) is actually affected not only by the outside air temperature but also by the temperature of the return air (RA) (corresponding to the load). For this reason, it is originally preferable to perform control in the operation control mode according to the outside air temperature and the return air (RA) temperature, but here, as described above, the return air (RA) temperature is considered to be constant. However, control shall be performed in the operation control mode according to the outside air temperature.

In FIG. 3, first, steps S11 to S14 show the processing operation of the control device 40 in the mode “A0-1” in FIG. As shown in FIG. 4, in the above mode “A0-1”, the outside air fan 14 is in the stopped state, and the brine pump 15 is intermittently operated (operated by repeating ON / OFF). During the operation in this intermittent operation, the rotation speed of the brine pump 15 is set to the minimum. Such an operation is realized by the control process of steps S11 to S14 by the control device 40.

In FIG. 3, in the initial state, the outside air fan 14, the brine pump 15, and the snow / ice pump 23 are all stopped. Further, it is assumed that the inside air fan 12 is controlled separately, and is not particularly described here.

In the processes of steps S11 to S14, the brine pump 15 is intermittently operated by steps S11, S13, and S14, and at any time, it is checked by step S12 whether or not the cooling is insufficient in the intermittent operation of the brine pump 15. .. In this check, when the temperature of the supply air (SA) cannot be maintained at the set temperature, it is determined that the cooling is insufficient. That is, in step S12, for example, it is determined whether or not the temperature measured by the air supply (SA) by the temperature sensor 3 is higher than the set temperature of SA (whether or not “measured temperature of SA> set temperature of SA”). If the determination result is YES, the process proceeds to step S15. As a result of this transition, in FIG. 4, the operation control is shifted from the mode “A0-1” to the mode “A0-2”.

To explain the processing of steps S11 to S14 in more detail, the brine pump 15 is started and operated at the minimum rotation speed (step S11), and the determination in step S12 is performed after a predetermined time (for example, 1 minute) has elapsed. As a result of this determination, when the temperature measured by the air supply (SA) by the temperature sensor 3 is equal to or lower than the set temperature of SA (when "measured temperature of SA ≤ SA set temperature") (step S12, NO), The brine pump 15 is stopped (step S13). Then, the timer is reset and restarted, and when the timer is up (for example, when 1 minute has passed) (step S14), the brine pump 15 is started again and the operation is performed with the rotation speed set to the minimum (step S11). .. Then, the determination in step S12 is performed. As a result of this determination, when the temperature measured by the air supply (SA) by the temperature sensor 3 becomes higher than the set temperature of SA (when "measured temperature of SA> set temperature of SA"), (step S12, YES), the mode shifts to the operation control mode in which the processes of steps S15 to S18 are performed. The operation control mode of the transition destination is the mode “A0-2” shown in FIG.

In the mode "A0-2", the brine pump 15 maintains the operation at the minimum rotation speed (continuous operation) while maintaining the step S11, and the outside air fan 14 is intermittently operated. During the operation in this intermittent operation, the rotation speed of the outside air fan 14 is set to the minimum.

In the processes of steps S15 to S18, the outside air fan 14 is started and operated at the minimum rotation speed (step S15), and when a predetermined time (for example, 1 minute) has elapsed, the determination in step S16 is performed. The determination (whether or not the cooling is insufficient) itself in step S16 is the same as the determination in step S12, and whether or not the temperature measured by the air supply (SA) by the temperature sensor 3 is higher than the set temperature of SA (whether or not it is insufficient). Whether or not "SA measurement temperature> SA set temperature" is determined). The difference between the two is that in step S12, whether or not the cooling is insufficient is determined in the state of intermittent operation of the brine pump 15, whereas in step S16, the intermittent operation of the outside air fan 14 and the minimum rotation speed of the brine pump 15 are used. It is a point to be performed in the state of simultaneous operation with the operation of.

When the temperature measured by the air supply (SA) by the temperature sensor 3 is equal to or lower than the set temperature of SA (when "measured temperature of SA ≤ SA set temperature") (step S16, NO), the outside air fan 14 is stopped. (Step S17). Then, the timer is reset and restarted, and when the timer is up (for example, after 1 minute has passed) (step S18), the outside air fan 14 is started again and operated at the minimum rotation speed (step S15).

When comparing the mode "A0-2" and the mode "A0-1", the mode "A0-2" consumes more power but has a higher cooling capacity.

When the result of the determination process in step S16 is YES, that is, when it is determined that the cooling is insufficient in the simultaneous operation of the intermittent operation of the outside air fan 14 and the operation of the brine pump 15 at the lowest rotation speed, steps S19 to S20 Shifts to the operation control mode in which the above processing is performed. As a result of this transition, in FIG. 4, the operation control is shifted from the mode “A0-2” to the mode A1.

As shown in FIG. 4, in mode A1, the outside air fan 14 is maintained at a constant minimum rotation speed (continuous operation), and the brine pump 15 is operated under PID control (step S19). This PID control (Proportional-Integral-Differential Controller) is a general control, and controls so that the temperature of the supply air SA (supply air temperature) becomes the set temperature. For example, when the temperature measured by the air supply (SA) by the temperature sensor 3 is higher than the set temperature of SA (when "measured temperature of SA> set temperature of SA"), the rotation speed of the brine pump 15 is increased by a certain number. Take control. On the other hand, when the SA measurement temperature by the temperature sensor 3 is lower than the SA set temperature (when "SA measurement temperature <SA set temperature"), the rotation speed of the brine pump 15 is controlled to be lowered by a certain number. Further, when the measured temperature of SA by the temperature sensor 3 and the set temperature of SA are equal (when "measured temperature of SA = set temperature of SA"), the rotation speed of the brine pump 15 is maintained as it is.

In this PID control, when the measured temperature of the supply air (SA) does not fall below the set temperature of SA even if the rotation speed of the brine pump 15 is maximized (100%) (when "measured temperature of SA> set temperature of SA"). ) (Step S20, YES), the process proceeds to step S21. As a result of this transition, in FIG. 4, the operation control is shifted from the mode A1 to the mode A2.

As shown in FIG. 4, in the mode A2, the operation of the brine pump 15 at a constant maximum rotation speed is maintained (continuous operation), and the outside air fan 14 is PID controlled (step S21). Similarly to step S19, the PID control in this case is also controlled so that the temperature of the supply air SA becomes the set temperature. For example, when the temperature measured by the air supply (SA) by the temperature sensor 3 is higher than the set temperature of SA (when "measured temperature of SA> set temperature of SA"), the rotation speed of the outside air fan 14 is increased by a certain number. Take control. On the other hand, when the temperature measured by the temperature sensor 3 for SA is lower than the set temperature for SA (when "measured temperature for SA <set temperature for SA"), the rotation speed of the outside air fan 14 is controlled to be lowered by a certain number. Then, when the measured temperature of SA by the temperature sensor 3 and the set temperature of SA are equal (when "measured temperature of SA = set temperature of SA"), the rotation speed of the outside air fan 14 is maintained as it is.

In this control, when the control of increasing the rotation speed of the outside air fan 14 by a certain number is repeated, the rotation speed of the outside air fan 14 becomes the maximum (100%) under the operating condition at the maximum rotation speed of the brine pump 15. ). In this state, the indirect outside air conditioner 10 is operated independently at the maximum cooling capacity. When the temperature measured by the air supply (SA) by the temperature sensor 3 does not fall below the set temperature of SA (when "measured temperature of SA> set temperature of SA") even in the state of independent operation with such maximum cooling capacity. (Step S22, YES) proceeds to step S23. As a result of this transition, in FIG. 4, the operation control is shifted from the mode A2 to the mode B1.

As shown in FIG. 4, the mode B1 operates the snow / ice pump 23, that is, puts the snow / ice cold / water air conditioner 20 into an operating state. That is, in all of the modes "A0-1", the mode "A0-2", the mode A1 and the mode A2 described so far, the snow-ice cold water air conditioner 20 is in the stopped state, and the indirect outside air air conditioner 10 is operated independently. This is the operation control mode. On the other hand, in the operation control of the mode B1, the indirect outside air conditioner 10 and the snow / ice cold water air conditioner 20 are operated in combination.

In the operation control in the mode B1, the operation of the brine pump 15 at a constant maximum rotation speed is maintained (continuous operation). If the step S22 is YES, the control device 40 first activates the snow and ice pump 23 (step S23). Then, the snow and ice pump 23 is PID controlled (step S24). Similar to step S19, the PID control in this case is also controlled so that the supply air temperature becomes the set temperature.

However, the rotation speed of the outside air fan 14 is controlled in conjunction with the PID control of the snow and ice pump 23 in step S23. For this purpose, for example, the user arbitrarily creates a correspondence table (not shown) in which the rotation speed of the snow / ice pump 23 and the rotation speed of the outside air fan 14 are associated with each other, and the control device 40 is provided with the above-mentioned. Store it in the built-in memory. Each time the control device 40 newly determines the rotation speed of the snow / ice pump 23 by PID control of the snow / ice pump 23, the rotation speed of the outside air fan 14 corresponding to this rotation speed is obtained from the association table, and the obtained rotation speed is obtained. The number controls the operation of the outside air fan 14. In this way, the control device 40 controls the flow rate of the chilled water circulating in the chilled water pipe 24 of the snow-ice chilled water chiller 20 and the rotation speed of the outside air fan 14 of the indirect outside air chiller 10 in association with each other. It facilitates control during combined operation of the indirect outside air conditioner 10 and the snow ice cold water air conditioner 20.

The association table is set so that the rotation speed of the outside air fan 14 decreases as the rotation speed of the snow and ice pump 23 increases. For example, the rotation speed of the snow / ice pump 23 is 20% and the rotation speed of the outside air fan 14 is 80%, and the rotation speed of the snow / ice pump 23 is 70% and the rotation speed of the outside air fan 14 is 30%. It is associated. However, the correspondence relationship between the rotation speed of the snow and ice pump 23 and the rotation speed of the outside air fan 14 set in the association table is not limited to this example. The percentage display represents the ratio of the number of revolutions to the maximum number of revolutions. For example, 20% means the number of revolutions corresponding to 20% of the maximum number of revolutions.

Further, in the illustrated example, while executing the process of step S24, the determination of "is the snow and ice pump 23 operated at maximum (at 100%)?" In step S25 is performed, and if the determination is NO, the loop returns to step S24. It becomes a process. Here, even if this determination is YES, the loop process returns to step S24 as in the case of NO. The process when the determination result in step S25 is YES is expressed in a confirmatory sense, and merely indicates, for example, that the vehicle is operating in the maximum air conditioning output state. ..

Further, in the above description, the rotation speed of the outside air fan 14 is reduced as the rotation speed of the snow / ice pump 23 increases in conjunction with the PID control of the snow / ice pump 23. The reason for doing this is that in a situation where the temperature of the outside air (OA) is so high that the independent operation of the indirect outside air cooler 10 cannot cope with it, the cooling effect of the brine by the outside air is small, and in some cases, the cooling effect of the brine is small. This is because it can be counterproductive. The adverse effect here is, for example, a case in which the temperature of the brine rises due to heat exchange with the outside air (OA), but is not limited to this case.

In the present embodiment, the liquid-liquid heat exchanger 31 is provided in the annular brine pipe 16 at the portion where the brine flows from the inside air heat exchanger 11 to the outside air heat exchanger 13. Therefore, the liquid-liquid heat exchanger 31 is after heat exchange with the return air (RA) by the inside air heat exchanger 11 for the brine, and with the outside air (OA) by the outside air heat exchanger 13 for the brine. Before the heat exchange of the above, the heat exchange between the cold water and the brine is performed. In this configuration, the brine sent to the inside air heat exchanger 11 is immediately after the heat exchange with the outside air (OA) by the outside air heat exchanger 13 after the heat exchange with the cold water by the liquid-liquid heat exchanger 31. It is a thing. According to this configuration, even if the heat exchange with cold water derived from snow and ice excessively lowers the temperature of the brine, the subsequent heat exchange with the outside air (OA) makes it possible to suppress the excessive temperature change of the brine. It is possible to prevent supercooling of the cooling target space by the snow-ice chilled water cooler 20 having a very high cooling capacity. Therefore, the requirement for fineness for controlling the rotation speed of the snow and ice pump 23 is relaxed, and the control becomes easy. Of course, the liquid-liquid heat exchanger 31 is located at a position higher than the inside air heat exchanger 11 on the annular brine pipe 16, and the brine flows from the outside air heat exchanger 13 to the inside air heat exchanger 11. It may be provided in the portion.

Further, in the mode B1 in the above-described embodiment, the control device 40 controls the rotation speed of the snow and ice pump 23 by PID, and in conjunction with this PID control, controls the rotation speed of the outside air fan 14 based on the association table. I try to do it. Instead, in this mode B1, the control device 40 controls the rotation speed of the outside air fan 14 by PID, and in conjunction with this PID control, controls the rotation speed of the snow and ice pump 23 based on the association table. You may do so. Since the PID control of the rotation speed of the outside air fan 14 in the mode B1 can share the PID control in the mode A2 described above, by doing so, the PID control for the snow and ice pump 23 becomes unnecessary, and the control can be performed. It will be easier.

As shown in FIG. 4, the control in the mode B1 essentially controls the amount of cold water flowing through the liquid-liquid heat exchanger 31, and as an example for that purpose, the snow and ice pump 23 as described above. However, the method of this control is not limited to this example. For example, a three-way valve (not shown) and a bypass pipe are further provided, and the valve opening degree of the three-way valve is controlled so that a part of the cold water supplied from the snow / ice pump 23 bypasses the liquid-liquid heat exchanger 31. Then, the amount of cold water flowing through the liquid-liquid heat exchanger 31 may be adjusted and controlled.

Further, in the mode B1, the outside air fan 14 is finally stopped (rotation speed is '0') as shown in the figure due to the rise in the outside air temperature. This state can be regarded as "substantially the indirect outside air conditioner 10 is not functioning", and may be regarded as a state substantially equivalent to the independent operation state of the snow / ice cold water air conditioner 20. That is, although the brine circulates in this state, there is almost no heat exchange between the brine and the outside air (OA) because the outside air fan 14 is stopped, and the liquid-liquid heat exchanger 31 exchanges heat with the cold water. It can be considered that only is done. That is, this state may be regarded as a state in which the return air (RA) is cooled by the cold heat of the cold water indirectly through the brine by the snow-ice cold water air conditioner 20 alone.

Further, as described above, FIG. 3 shows a situation in which the temperature continues to rise from a low temperature state, and does not show a case where the temperature drops, so a case where the temperature drops will be described.

First, when the temperature of the outside air (OA) drops during operation under the control in mode B1, the rotation speed of the snow / ice pump 23 is reduced accordingly. If the temperature of the outside air (OA) continues to decrease, the snow and ice pump 23 will eventually be stopped (rotation speed = 0). At this time, the control device 40 shifts the operation control from the mode B1 to the mode A2. Although not shown in FIG. 3, in the mode B1, the control device 40 executes the PID control of the snow / ice pump 23 in step S24, and at any time, together with the determination process in step S25, for example, “the snow / ice pump 23 is in a stopped state ( It also performs a process of determining "whether or not the rotation speed = 0)". Then, when it is determined that the snow / ice pump 23 is in the stopped state, the process proceeds to step S21. By this transition, the control device 40 shifts the operation control from the mode B1 to the mode A2.

When the temperature of the outside air (OA) drops during operation under the control of mode A2, the rotation speed of the outside air fan 14 is reduced accordingly. When the temperature of the outside air (OA) continues to decrease, the outside air fan 14 is eventually operated at the minimum rotation speed. At this time, the control device 40 shifts the operation control from the mode A2 to the mode A1. Although not shown in FIG. 3, in the mode A2, the control device 40 executes the PID control of the outside air fan 14 in step S21, and at any time, together with the determination process of step S22, for example, "the outside air fan 14 has the minimum rotation speed". It also performs a process of determining "whether or not". Then, when it is determined that the outside air fan 14 is operating at the minimum rotation speed, the process proceeds to step S19. By this transition, the control device 40 shifts the operation control from the mode A2 to the mode A1.

When the temperature of the outside air (OA) drops during operation under the control of mode A1, the rotation speed of the brine pump 15 is reduced accordingly. When the temperature of the outside air (OA) continues to decrease, the brine pump 15 is eventually operated at the minimum rotation speed. At this time, the control device 40 shifts the operation control from the mode A1 to the mode "A0-2". Although not shown in FIG. 3, in the mode A1, the control device 40 executes the PID control of the brine pump 15 in step S19, and at any time, together with the determination process of step S20, for example, "the brine pump 15 has the minimum rotation speed". It also performs a process of determining "whether or not". Then, when it is determined that the brine pump 15 is operating at the minimum rotation speed, the process proceeds to step S15. By this transition, the control device 40 shifts the operation control from the mode A1 to the mode "A0-2".

As described above, during the operation control in the mode “A0-2”, the control device 40 operates the brine pump 15 at the minimum rotation speed instead of controlling according to the temperature of the outside air (OA). Control is performed to intermittently operate the outside air fan 14. Although not shown in FIG. 3, in this mode "A0-2", the control device 40 may perform, for example, "whether or not the air conditioner is excessive" in addition to the determination process of step S16 at any time. It may be. Here, if it is determined that the cooling is excessive, the control device 40 shifts the operation control from the mode "A0-2" to the mode "A0-1".

In the determination of whether or not the cooling is excessive, for example, when the measured temperature of the supply air (SA) is lower than the SA set temperature to some extent or more, it is determined that the cooling is excessive. That is, it is determined whether or not "measured temperature of air supply (SA) + α ≤ SA set temperature" (however, α is a positive value set arbitrarily in advance), and when this determination result is YES. , Make a judgment that the air conditioner is excessive.
[2: Operation example during power saving operation]
As described in the above-described operation example during normal operation, when the control device 40 performs operation control in mode B1, the snow / ice air conditioner system of FIG. 2 has an indirect outside air cooler 10 and snow / ice cold water cooling. Combined operation with the machine 20 is being performed. During this combined operation, the brine pump 15 is maintained at a constant maximum rotation speed.

The power-saving operation in the snow-ice-using air-conditioning system of FIG. 2 is an operation in which the operation of the brine pump 15 is stopped during this combined operation, and then the snow-ice-using air-conditioning system continues to provide the cooling function of the cooling target space. ..

As described above, in the snow-ice utilization air conditioning system of FIG. 2, the liquid-liquid heat exchanger 31 is installed at the position where the height in the vertical direction is the highest on the path of the brine pipe 16, and the height in the vertical direction is high. The internal air heat exchanger 11 is installed at the lowest position. Therefore, the heat exchange (third heat exchange) by the liquid-liquid heat exchanger 31 is higher than the position on the brine pipe 16 where the heat exchange (first heat exchange) is performed by the internal air heat exchanger 11. It is configured to be done in.

When the control device 40 controls the operation in the mode B1, the brine is cooled by heat exchange with the cold water of the snow-ice cold water air conditioner 20 in the liquid-liquid heat exchanger 31. The cooled brine cools the return air (RA) from the cooling target space by heat exchange in the internal air heat exchanger 11. The cooled return air (RA) is supplied as the supply air (SA) to cool the cooling target space. At this time, the brine shrinks and becomes denser by being cooled by heat exchange in the liquid-liquid heat exchanger 31, while returning air (RA) by heat exchange in the internal air heat exchanger 11. As the temperature rises due to cooling, it expands and becomes less dense. That is, due to heat exchange at two positions having different heights in the brine pipe 16, the density of the brine increases at the high position and the density decreases at the low height position, so that gravity Convection of brine (heat convection) is generated by the action of. The heat convection of this brine is used in the power saving operation.

In the power saving operation, the brine pump 15 in operation causes the brine to flow (forced convection), so that the brine circulating in the brine pipe 16 is subjected to heat convection (natural convection) even after the brine pump 15 is stopped. It is circulated in the brine pipe 16. According to this power saving operation, since the brine pump 15 is stopped, the power consumed by the brine pump 15 for forcibly flowing the brine in the brine pipe 16 is saved. Therefore, by causing the snow and ice utilization air conditioner system of FIG. 2 to perform the power saving operation, the energy consumption during the combined operation of the indirect outside air cooler 10 and the snow and ice cold water cooler 20 is reduced.

During this power saving operation, the control device 40 controls the snow and ice pump 23 and the outside air fan 14 in the same manner as the operation control in mode B1 so that the temperature of the supply air SA becomes the set temperature. To do.

In this power saving operation, for example, when the administrator of the snow and ice utilization air conditioner system of FIG. 2 operates the indirect outside air conditioner 10 and the snow and ice cold water air conditioner 20 together (when the operation is controlled in mode B1), the brine pump 15 is operated. It may be made to function by manually performing the operation for stopping. Further, for example, during the power saving operation, the administrator manually performs an operation for restarting the brine pump 15 to control the operation of the snow and ice utilization air conditioning system of FIG. 2 in mode B1 in the normal operation. It may be restored.

Further, for example, during the normal operation of the above-mentioned snow and ice air-conditioning system, when the control device 40 detects that the predetermined operation start condition is satisfied, the brine pump 15 is controlled to be stopped to start the power saving operation. You may. The operation start condition is, for example, a predetermined time of the temperature measurement value of the air supply (SA) by the temperature sensor 3 during the operation control in the mode B1 or the operation control in the mode B1. In some cases, the amount of change within the range remains within a predetermined range.

Further, for example, during the power saving operation, when the control device 40 detects that the predetermined operation stop condition is satisfied, the brine pump 15 is controlled to be restarted so as to return to the operation control in the mode B1 in the normal operation. It may be. The operation stop condition is, for example, when the measured value of the temperature of the supply air (SA) by the temperature sensor 3 changes by a predetermined value or more after the start of the power saving operation, or the amount of change of the measured value per unit time. In some cases, the amount of change exceeds a predetermined level.

In addition, this power saving operation is for avoiding a complete stop of the cooling function of the cooling target space when the brine pump 15 is stopped for failure repair or maintenance inspection in the snow and ice utilization air conditioning system of FIG. 2, for example. It can also be used as a temporary measure.

Further, for example, in the snow / ice air conditioning system of FIG. 2, an emergency power source that replaces the power supply in the event of a power failure is provided in the inside air fan 12, the outside air fan 14, and the snow / ice pump 23, while the brine pump 15 is provided. You may not have it. However, when this configuration is adopted, the power saving operation is performed by the snow and ice air conditioning system when a power failure occurs, and even if the brine pump 15 is stopped due to the power failure, the cooling function of the cooling target space by the snow and ice air conditioning system is performed. Avoid a complete outage. By doing so, it is possible to reduce the number of emergency power supplies that should be prepared in advance in case of a power failure.

In the snow-ice utilization air-conditioning system of FIG. 2, the indoor unit 1 is installed inside the snow-ice (snow mountain) 21, the water melting tank 22, and the snow-ice pump 23 among the components of the snow-ice cold water air conditioner 20. It is not installed on the roof of the building, but is installed in a different location from the building. As a result, the snow and ice 21 can be easily carried in, and the snow and ice 21 can be prevented from being melted by the heat generated from the inside of the building. Furthermore, by not installing these heavy objects on the roof, the strength requirement for the building is relaxed. However, it is of course possible to install some or all of the components of these snow-ice cold water air conditioners 20 on the roof of the building. Further, the outdoor unit 2 of the indirect outdoor air conditioner 10 in the snow and ice utilization air conditioner system of FIG. 2 is not installed on the roof of the building in which the indoor unit 1 is installed, but is installed at a position different from the building. , The brine pipe 16 may be extended as needed.

Further, for example, even if the snow and ice air conditioning system of FIG. 2 is installed on a slope and arranged so that the difference in height between the liquid-liquid heat exchanger 31 and the water melting tank 22 and the cold water pipe 24 in the vertical direction becomes small. Often, these components may be arranged on a single horizontal plane. With such an arrangement, the load on the snow and ice pump 23 for circulating the cold water in the cold water pipe 24 is lightened, and the power consumption is reduced.

Having described in detail the embodiments of the disclosure and its advantages, those skilled in the art will be able to make various changes, additions and omissions without departing from the scope of the invention as expressly stated in the claims. Let's do it.

1 Indoor unit 2 Outdoor unit 3 Temperature sensor 10 Indirect outside air cooler 11 Inside air heat exchanger 12 Inside air fan 13 Outside air heat exchanger 14 Outside air fan 15 Brine pump 16 Brine piping 20 Snow ice Cold water cooler 21 Snow ice (snow mountain)
22 Water melting tank 23 Snow and ice pump 24 Cold water pipe 31 Liquid-liquid heat exchanger

Claims (4)

A first pipe, which is a circulation path through which the refrigerant circulates, a refrigerant pump that circulates the refrigerant in the first pipe, and a first heat exchange between the return air, which is the return air from the space to be air-conditioned, and the refrigerant. An indirect outside air cooler having a first heat exchanger for cooling the return air and a second heat exchanger for exchanging a second heat between the outside air and the refrigerant to dissipate the refrigerant. When,
It has a second pipe that is a circulation path through which cold water circulates, and a snow ice pump that circulates the cold water in the second pipe, and cools the cold water that circulates in the second pipe by the cold heat of a snowy mountain. Snow and ice cold water air conditioner and
A third heat exchanger that cools the refrigerant by performing a third heat exchange between the refrigerant in the first pipe and the cold water in the second pipe.
Have,
The third heat exchanger performs the third heat exchange at a position on the first pipe and higher than the position where the first heat exchange is performed, and uses the cold water for the refrigerant. Cool and
After the operating refrigerant pump is stopped, the indirect outside air cooler uses the refrigerant by the thermal convection of the refrigerant generated by cooling the refrigerant with the cold water by the third heat exchange, thereby causing the refrigerant to be the first. Circulate in the pipe,
An air-conditioning system that uses snow and ice. The snow and ice utilization air conditioning system according to claim 1, wherein the third heat exchanger performs the third heat exchange at a position where the height of the first pipe is the highest. The snow and ice utilization air conditioning system according to claim 1 or 2, wherein the first heat exchanger performs the first heat exchange at a position where the height of the first pipe is the lowest. The second heat exchanger is characterized in that the second heat exchange is performed at a position on the first pipe and higher than the position where the first heat exchange is performed. The snow and ice air conditioning system according to any one of claims 1 to 3.

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