JP6413713B2 - Snow and ice air conditioning system - Google Patents

Description

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

In recent years, an air conditioning system has been considered in which a snowy mountain is created from snowfall in winter in a snowy region and the like, and the cold heat of this snowy mountain is used outside of winter.
For example, the prior art described in Patent Document 1 includes a snow storage unit in which snow is accumulated outside the room. Then, switching between the outside air OA and the snow-cooled outside air SOA is led to the outside air passage, and the cooling heat of the snow-cold water is led to the cooling coil.

JP 2012-145289 A

  According to Patent Document 1, there is a device that generates a large amount of heat in the room, and the room temperature / humidity tolerance range is narrow and the management is strictly controlled. In order to prevent insufficient humidification with respect to the supply air due to this, it is necessary to provide humidification means for humidification.

  An object of the present invention is to provide an air-conditioning system that uses snow and ice and has a high energy-saving effect, which is composed of an indirect outside air cooler and a snow-ice cold water cooler without using a refrigerator. In particular, the present invention is to provide a snow and ice utilization air conditioning system and the like that can obtain a higher energy saving effect by efficiently operating an indirect outside air cooler and a snow and ice cold water cooler.

The snow / ice use air conditioning system of this example uses an indirect outside air cooler for cooling the return air, which is return air from the air-conditioning target space, using outside air, and the return air using cold water generated by a snowy mountain. And a snow and ice cold water cooler for cooling and a control device for controlling the indirect outside air cooler and the snow and ice cold water cooler .
The snow-ice chilled water cooler includes a chilled water pipe and a first pump for supplying chilled water generated by snowy mountains to the first heat exchanger, and the return after passing through the indirect outside air chiller when the chilled water is supplied. and said a gas cold water and a first heat exchanger for exchanging heat.

The control device includes a first mode of operating the indirect outdoor air cooling machine alone, and a second mode for combined operation of the snow and ice cold water cooling device and the indirect outdoor air cooling machine to operate the snow and ice cold water cooling machine alone Using each mode of the third mode, the indirect outside air cooler and the snow / ice cold water cooler are controlled , and in the control using the second mode, the indirect outside air cooler is operated at a maximum cooling capacity, and The amount of cold water supplied to the first heat exchanger of the snow / ice cold water cooler is adjusted to an arbitrary ratio .

  According to the snow-ice-use air conditioning system of the present invention, etc., it is an air-conditioning system that uses snow-ice, and is composed of an indirect outside air cooler and a snow-ice cold water cooler without using a refrigerator. I will provide a. Furthermore, it is possible to obtain a higher energy saving effect by particularly efficiently operating the indirect outdoor air cooler and the snow / ice cold water cooler.

It is a block diagram of the snow-ice utilization air conditioning system of this example. It is a figure which shows schematically the operating method of the air conditioning system of this example. It is a figure which shows the example of control processing of the air conditioning system of this example. It is a mode transition table.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram of the snow-ice-use air conditioning system of this example.
The snow / ice use air conditioning system of this example (hereinafter simply referred to as an air conditioning system) includes an indirect outdoor air cooler (hereinafter also referred to simply as an outdoor air cooler) and a snow / ice cold water cooler. It is an air conditioner used together. The air-conditioning system using snow and ice of this example does not include an air conditioner based on a vapor compression refrigeration cycle (an air conditioner composed of a compressor, an evaporator, etc .; it will be referred to as a general refrigerator). In this way, it is composed of an indirect outside air cooler and a snow / ice chilled water cooler without using a refrigerator (general chiller). Providing an air-conditioning system with high energy-saving effect that can preserve the cold energy of snow and ice by controlling the snow and ice chilled water cooler to operate as much as the lack of capacity in the outside air cooler. Can do.

  In FIG. 1, the configuration related to the indirect outside air cooler is a sensible heat exchanger 11, a sensible heat exchanger 21, a pump 22, a fan 23, and a pipe 14. Further, the configuration related to the snow / ice cold water cooler includes a heat exchanger 12, a cold water pump 31, a cold water three-way valve 32, a cold water pipe 33, and a snowy mountain. Moreover, the fan 13 is provided as a structure common to an indirect outdoor air cooler and a snow-ice cold water cooler. Furthermore, the control apparatus 40 which controls the whole air conditioning system shown in figure is provided.

  The control device 40 is connected to the illustrated outside air temperature sensor 24, the return air temperature sensor 16, the supply air temperature sensor 15 and the like via a communication line (not illustrated). Then, the control device 40 transmits the temperature measurement value of the outside air OA by the outside air temperature sensor 24, the temperature measurement value of the return air RA by the return air temperature sensor 16, and the supply by the supply air temperature sensor 15 from these various sensors via communication lines. The temperature measurement value of the air SA is input at any time.

  Moreover, the control apparatus 40 is connected with the fan 23, the fan 13, the pump 22, the cold water pump 31, the cold water three-way valve 32, etc. via the communication line not shown. And these each structure is controlled via this communication line. That is, the control device 40 executes, for example, start / stop of the fan 23 and the fan 13 and control of the fan rotation speed via a communication line (not shown). Or control device 40 performs starting / stop of pump 22, cold water pump 31, and control of the number of rotations of a pump via a communication line not illustrated, for example. Or the control apparatus 40 performs control of the valve opening degree of the cold water three-way valve 32 via a communication line not shown, for example.

  As described above, the control device 40 is a control device that controls the snow-ice-use air conditioning system of this example. Specific processing examples by the control device 40 will be described later with reference to FIGS. 2, 3, 4, and the like.

  As for the indirect outside air cooler, the refrigerant flows in the pipe 14, and the refrigerant is circulated to the sensible heat exchanger 11 and the sensible heat exchanger 21 through the pipe 14 by the pump 22. The refrigerant is an antifreeze such as a propylene glycol aqueous solution.

  Regarding the snow / ice cold water cooler, cold water is circulated in the cold water pipe 33 by the pumping of the cold water pump 31, and the cold water may be supplied to the heat exchanger 12. While the cold water is being supplied to the heat exchanger 12, the return air RA is cooled by the heat exchanger 12.

  The amount of cold water supplied to the heat exchanger 12 is adjusted by the cold water three-way valve 32. That is, the cold water three-way valve 32 bypasses the heat exchanger 12 and the direction in which the cold water pumped in from the cold water pump 31 is supplied to the heat exchanger 12 at an arbitrary ratio (0:10 to 10: 0). In the direction you want to flow. That is, the amount of cold water supplied to the heat exchanger 12 can be adjusted to an arbitrary ratio between 0% and 100% of the inflow amount.

  The cold water is obtained by, for example, melting snow from a snowy mountain into the cold water pipe 33. However, the present invention is not limited to this example. The water may be circulated in the pipe, and the water may be cooled by the cold heat of the snowy mountains to form cold water.

  Many of the above configurations may be provided inside one of the two housings. The two cases are the inside air unit 10 and the outside air unit 20 shown in the figure. The inside air unit 10 is provided in an arbitrary building having a space to be air-conditioned (server room or the like), and the outside air unit 20 is provided outside the building. Inside air (building air; in particular, return air RA) passes through the inside air unit 10, and outside air passes through the outside air unit 20.

  In the case of the illustrated example, the sensible heat exchanger 11, the heat exchanger 12, and the fan 13 are provided in the inside air unit 10. Further, a part of the pipe 14 for supplying the refrigerant to the sensible heat exchanger 11 and a part of the cold water pipe 33 for supplying the cold water to the heat exchanger 12 are provided in the inside air unit 10. .

  The fan 13 takes in the return air RA into the inside air unit 10, passes it through the sensible heat exchanger 11 → the heat exchanger 12 in this order, and then forms an air flow that is sent out as the supply air SA. The return air RA is return air from an air conditioning target space (not shown). The return air RA is basically cooled by passing through the sensible heat exchanger 11 and the heat exchanger 12 to become cold air, and this cold air is supplied to the air conditioning target space as the supply air SA.

  The air-conditioning target space is, for example, a server room, a data center, or the like, and is a space in which a large number of electronic devices such as computer devices that serve as heating elements during operation are installed. The cold air (supply air SA) supplied to the air-conditioning target space cools the computer device and the like, and thereby the temperature rises to warm air. This warm air is sucked into the inside air unit 10 as the return air RA.

  In the illustrated example, the sensible heat exchanger 21, the pump 22, the fan 23, the cold water three-way valve 32 and the like are provided in the outside air unit 20, and a part of the pipe 14 and the cold water pipe 33 are also provided. ing. Another part of the cold water pipe 33 is also provided outside the outside air unit, and passes through the snowy mountains.

  Note that the fan 23 forms an air flow in which the outside air OA is taken into the outside air unit 20 during operation and passes through the sensible heat exchanger 21 and then discharged to the outside of the outside air unit 20 as the illustrated exhaust EA. A fan to do.

An operation method (control processing by the control device 40) of the air conditioning system of this example having the above configuration will be described below.
Here, FIG. 2 is a diagram schematically showing an operation method of the air conditioning system of FIG. An example of a detailed control method will be described later with reference to FIGS. Here, first, it will be schematically described with reference to FIG.

  Here, first, in the graph shown in FIG. 2, the horizontal axis is “outside air temperature−return air temperature”. This outside air temperature is the temperature of the outside air OA measured by the outside air temperature sensor 24 shown in FIG. The return air temperature is the temperature of the return air RA measured by the return air temperature sensor 16 shown in FIG. If the return air temperature is constant, the change in “outside air temperature−return air temperature” may be regarded as a change in “outside air temperature”. Thus, in the following description, the horizontal axis is assumed to be “outside air temperature”.

  Moreover, the vertical axis | shaft of the graph shown in FIG. 2 is a cooling capacity. What is indicated by a dotted line in the figure is the cooling capacity of the indirect outside air cooler according to the horizontal axis (outside air temperature). As indicated by the dotted line, the lower the outside air temperature, the higher the cooling capacity of the indirect outside air cooler. Here, the cooling capacity required to set the temperature of the supply air SA to the set temperature is the required cooling capacity shown in the figure.

  As shown by a dotted line in FIG. 2, in a situation where the outside air temperature is low to some extent, the cooling capacity of the indirect outside air cooler is larger than the necessary cooling capacity. Therefore, in this situation, a mode in which the indirect outside air cooler is operated alone ((1) outside air cooling alone operation shown in the drawing) is set. In this mode (1), the snow / ice cold water cooler is stopped. A specific control example will be described later with reference to FIGS.

  Further, when the outside air temperature becomes high to some extent, as shown by a dotted line in FIG. 2, the cooling capacity of the indirect outside air cooler becomes smaller than the required cooling capacity. In this situation, a mode in which the indirect outside air cooler and the snow and ice cold water cooler are operated in combination ("(2) Outside air cooling + cold water cooling (combined operation)" shown in the figure) is used to compensate for the lack of cooling capacity. To. In this mode (2), adjustment control is performed so that the cooling capacity of the snow / ice cooling water cooler is the difference between the required cooling capacity shown in the figure and the cooling capacity of the outside air cooling according to the outside air temperature at that time. The adjustment of the cooling capacity is realized by controlling the valve opening degree of the cold water three-way valve 32 and adjusting the amount of cold water supplied to the heat exchanger 12.

  For example, in the state of operation in mode (1), when the temperature of the supply air SA cannot be maintained at the set temperature only with the indirect outside air cooler (when the supply air temperature> the set temperature), the above Change mode to mode (2). Then, as described above, the temperature of the supply air SA (supply air temperature) is maintained at the set temperature by controlling the valve opening of the cold water three-way valve 32 and adjusting the amount of cold water supplied to the heat exchanger 12. To do.

  Then, in a situation where the outside air temperature is further increased and the cooling capacity of the indirect outside air cooler becomes “0” or less, there is no point in operating the indirect outside air cooler, so the indirect outside air cooler is stopped. In other words, the mode is such that the snow and ice cold water cooler is operated independently ((3) cold water cooler isolated operation shown in the figure). In this mode (3), in order to stop the operation of the indirect outside air cooler, for example, the pump 22 and the fan 23 are stopped. In addition, since the fan 13 is a structure shared with a snow-ice cold water cooler, it does not stop.

The control method of the air conditioning system of the present example will be described below in further detail using specific examples shown in FIGS.
In this example, first, mode (1) is further classified into the three modes of mode (1), mode (2), and mode (3). That is, as shown in FIG. 3, the mode (1) is divided into four modes of mode “A0-2”, mode “A0-1”, mode A1, and mode A2.

  FIG. 3 shows the operation contents of each configuration in the four modes related to the mode (1) and the modes (2) and (3). In addition, FIG. 4 shows determination conditions for mode transition of these six modes. In other words, FIG. 3 is a diagram showing an example of control processing of the air conditioning system of this example, and FIG. 4 is a mode transition table.

  As shown in FIG. 4, the transition destination in the mode transition is limited to a mode adjacent to the current mode. As shown in the lower side of FIG. 3, the adjacent modes are, for example, the modes “A0-2” and mode A2 that are adjacent to the mode A1.

Further, as shown in FIG. 3, the mode (2) is referred to as mode C and the mode (3) is referred to as mode D here.
First, with reference to FIG. 3, the driving | running method in each said mode is demonstrated.

FIG. 3 also shows a specific example of the supply air temperature and the return air temperature and a specific example of the temperature of the outside air OA, but these are not particularly described.
First, FIG. 3 shows the operation of the outside air fan in the upper part, the operation of the pump in the middle part, and the operation of the cold water three-way valve in the lower part. The outside air fan is the fan 23 in FIG. This is a pump 22.

  As shown in FIG. 3, in the mode “A0-1”, the outside air fan (fan 23) is in a stopped state, and the pump 22 is intermittently operated. In other words, the vehicle is operated by repeating ON / OFF. In this intermittent operation, the rotational speed of the pump 22 is minimized. Although not described one by one, not only in the mode “A0-1” but in all modes related to the mode (1), the chilled water three-way valve 32 has the valve opening on the heat exchanger 12 side set to 0%. That is, the valve on the heat exchanger 12 side is completely closed, and therefore, no cold water is supplied to the heat exchanger 12. Alternatively, the cold water pump 31 is stopped.

  Further, as shown in FIG. 3, in the mode “A0-2”, the pump 22 is in a state where the minimum rotational speed is constant, and the outside air fan is intermittently operated. It should be noted that the rotational speed of the outside air fan is minimized during the intermittent operation.

When the mode “A0-2” is compared with the mode “A0-1”, the mode “A0-2” has higher power consumption and higher cooling capacity.
Also, as shown in FIG. 3, in mode A1, the outside air fan is operated at a constant minimum rotational speed, and the pump 22 is PID controlled. This PID control is general control, and is controlled so that the temperature of the supply air SA (supply air temperature) becomes a set temperature. For example, if “supply air temperature> set temperature”, the rotation speed of the pump 22 is increased. However, if “supply air temperature ≦ set temperature” does not occur even when the rotation speed of the pump 22 is maximized, the mode A2 is entered. Will transition.

In addition, the said supply air temperature acquires the measured value of the supply air temperature sensor 15 shown in FIG. 1 at any time.
Further, as shown in FIG. 3, in mode A2, the pump 22 is operated at a constant maximum rotational speed, and the outside air fan is PID-controlled. Of course, also in this case, PID control is performed so that the supply air temperature becomes the set temperature. For example, if “supply air temperature> set temperature”, the rotational speed of the fan 23 is increased. However, if “supply air temperature ≦ set temperature” is not satisfied even if the rotational speed of the fan 23 is maximized, the mode C is entered. Will transition.

  Further, as shown in FIG. 3, in mode C, both the outdoor air fan and the pump 22 are operated at a constant maximum rotational speed, and the snow / ice cold water cooler is put into an operating state. That is, PID control related to the opening degree of the cold water three-way valve 32 is performed while the cold water pump 31 is in operation. Of course, also in this case, PID control is performed so that the supply air temperature becomes the set temperature.

Note that the chilled water pump 31 may be started when the mode A2 is changed to the mode C, and conversely, the chilled water pump 31 may be stopped when the mode C is changed to the mode A2.
Here, when the outside air temperature (OA temperature) becomes higher than the return air temperature (RA temperature), there is no point in operating the indirect outside air cooler. Therefore, in such a case, the mode D is set.

  Accordingly, in the mode D, as shown in FIG. 3, the outside air fan and the pump 22 are stopped and the snow / ice cold water cooler is operated independently. As in the case of mode C, the operation control of the snow / ice cold water cooler performs PID control related to the opening degree of the cold water three-way valve 32. Of course, also in this case, PID control is performed so that the supply air temperature becomes the set temperature.

Hereinafter, the mode transition determination process will be described with reference to the mode transition table of FIG.
In addition, the mode transition determination process according to the mode transition table of FIG.

  The mode transition table of FIG. 4 shows each mode transition from the state in which the outside air temperature is low until the outside air temperature rises and finally becomes the mode D, and further the outside air temperature decreases from the mode D. Each mode transition until it finally becomes mode “A0-1” is shown. Hereinafter, description will be made in order from the top.

  First, the determination condition for the transition from the mode “A0-1” to the mode “A0-2” is shown at the top of the mode transition table in FIG. Here, the determination condition includes two types of determination conditions of “temperature” and “apparatus”. If both determination conditions are not satisfied, the mode transition is not executed. However, the judgment condition of “device” related to the transition from mode “A0-1” to mode “A0-2” is only to confirm that the current mode is mode “A0-1”, and therefore there is none. May be. The same applies to the transition from mode “A0-2” to mode A1.

  The “temperature” condition in the determination condition for the transition from the mode “A0-1” to the mode “A0-2” is “SA temperature> SA set value + α” as shown in the figure. This is basically “SA temperature> SA set value”, and + α is not essential. However, + α is used mainly for preventing hunting together with “SA temperature> SA set value−β” described later. In this case, hunting means “transition from“ A0-1 ”to“ A0-2 ”” and “transition from“ A0-2 ”to“ A0-1 ””. The phenomenon is repeated.

  From the above, in the following explanation, without considering the above α and β, explanation is made using “SA temperature> SA set value” or “SA temperature <SA set value” as basic determination conditions. There is a case to do. The SA temperature is the supply air temperature measured by the supply air temperature sensor 15 in FIG. The SA set value is a set temperature arbitrarily set by the user or the like regarding the SA temperature. The SA set value is stored in an arbitrary memory area. In addition, the user may change the SA setting value.

  From the above, it is assumed here that the “temperature” determination condition for the transition from mode “A0-1” to mode “A0-2” is “SA temperature> SA set value”. In addition, although the determination condition of “device” for this transition is as shown in the figure, as described above, this is a confirming meaning. If the current mode is mode “A0-1”, this condition Should meet. Of course, the control device 40 can recognize the current mode.

  From the above, when “SA temperature> SA set value” when the current mode is mode “A0-1”, that is, when the temperature of the supply air SA is higher than the set temperature, Transition from mode "A0-1" to mode "A0-2". That is, as described above, the pump 22 is set to the minimum rotation speed from the intermittent operation, and the fan 23 is changed from the stopped state to the intermittent operation state.

  Similarly to the above, regarding the transition from the mode “A0-2” to the mode A1, when the current mode is the mode “A0-2”, “SA temperature> SA set value”, that is, supply When the temperature of the air SA becomes higher than the set temperature, the mode “A0-2” is transited to the mode A1.

  Subsequently, regarding the transition from the mode A1 to the mode A2, as shown in FIG. 4, the “temperature” determination condition is “SA temperature> SA set value” as described above. Further, the “apparatus” determination condition is “outside air fan rotation speed lower limit” and “pump rotation speed upper limit”. However, since the mode A1 is a mode in which the outside air fan is operated at a constant minimum rotation speed, the “outside air fan rotation speed lower limit” is a confirmation meaning of the mode A1, and is not essential. On the other hand, the condition of “upper pump speed” is indispensable. Accordingly, the transition condition from the mode A1 to the mode A2 may be regarded as “SA temperature> SA set value” and “pump rotational speed upper limit”.

  As described above, PID control of the pump 22 is performed in mode A1. Thus, for example, when the state of “SA temperature> SA set value” is reached, the SA temperature is controlled to maintain the A set value by increasing the rotation speed of the pump 22. However, if “SA temperature> SA set value” in the state where the pump 22 is operating at the maximum rotation speed, the mode A1 cannot cope. Accordingly, when “SA temperature> SA set value” is satisfied in the state where the pump 22 is at the maximum rotational speed, the mode A1 is shifted to the mode A2.

  Regarding the transition from mode A2 to mode C, as shown in FIG. 4, the “temperature” determination condition is “SA temperature> SA set value” as described above. Further, the “apparatus” determination condition is “upper limit of outside air fan speed”.

  As described above, in mode A2, the pump 22 is operated at a constant maximum rotational speed, and the fan 23 is PID-controlled. For example, when the state of “SA temperature> SA set value” is reached, the SA temperature is controlled to be maintained at the SA set value by increasing the rotational speed of the fan 23. However, if “SA temperature> SA set value” is satisfied in the state where the fan 23 is operated at the maximum rotational speed, the mode A2 cannot cope. This means that the situation cannot be dealt with by the independent operation of the indirect outside air cooler.

  Accordingly, when “SA temperature> SA set value” is satisfied in the state where the fan 23 is at the maximum rotation speed, the mode A2 is changed to the mode C. That is, the combined operation of the indirect outdoor air cooler and the snow / ice cold water cooler is started. For this purpose, for example, the cold water pump 31 is started and PID control related to the opening degree of the cold water three-way valve 32 is performed. That is, for example, when “SA temperature> SA set value”, the SA temperature is controlled to maintain the SA set value by increasing the valve opening. The indirect outside air cooler will continue to operate at maximum capacity. Although not described one by one, the valve opening basically means the opening of the valve on the heat exchanger 12 side. Therefore, if the valve opening is increased, the amount of cold water supplied to the heat exchanger 12 is increased.

  Further, as shown in FIG. 4, when “RA temperature <OA temperature” is satisfied during operation in mode C, transition to mode D is made. If “RA temperature> OA temperature” during operation in mode D, transition to mode C is made. The RA temperature is a measured value of the temperature of the return air RA, and is measured at any time by the return air temperature sensor 16 of FIG. The OA temperature is a measured value of the temperature of the outside air OA, for example, a measured value by the outside air temperature sensor 24 shown in FIG.

  The transition condition from mode C to mode A2 is “SA temperature <SA set value” and “cold water three-way valve closed” (valve opening degree 0%). That is, during operation in mode C, even if the valve opening degree of the cold water three-way valve 32 is set to 0% (minimum), if “SA temperature <SA set value” is established, the mode C is shifted to mode A2. From the above, when the valve opening degree is 0%, the amount of cold water supplied to the heat exchanger 12 becomes zero.

  When the chilled water three-way valve 32 has a valve opening of 0%, the snow / ice chilled water cooler is practically not functioning. In this state, if the temperature of the supply air SA becomes less than the set value, indirect outside air It can be assumed that the situation is such that it can be handled by operating the air conditioner alone. Thus, the mode C is transited to the mode A2.

  In the illustrated specific example, the “temperature” determination condition is “SA temperature <SA set value−β”. This prevents hunting together with the “SA temperature> SA set value + α”. In other words, it is assumed that “SA temperature> SA set value + α” in mode A2 and therefore the mode C is entered, but immediately after that, the SA temperature slightly decreases to “SA temperature <SA set value + α”. However, since it is unlikely that “SA temperature <SA set value−β”, it is not necessary to return to mode A2.

  Further, the transition condition from mode A2 to mode A1 is substantially “SA temperature <SA set value” and “outside air fan rotation speed lower limit”. That is, in mode A2, the rotational speed variable control of the fan 23 is performed as described above, and when “SA temperature <SA set value” is satisfied, the rotational speed of the fan 23 is decreased. However, when “SA temperature <SA set value” is satisfied with the rotational speed of the fan 23 lowered to the minimum, the mode A2 is shifted to the mode A1. In addition, although there is a “pump rotation speed upper limit” as shown in the transition conditions, the pump 22 is operated at a constant maximum rotation speed in the mode A2 as described above. is not.

  Further, the transition condition from the mode A1 to the mode “A0-2” is substantially “SA temperature <SA set value” and “pump rotational speed lower limit”. That is, in the mode A1, the rotational speed variable control of the pump 22 is performed as described above, and when “SA temperature <SA set value”, the rotational speed of the pump 22 is decreased. However, when “SA temperature <SA set value” when the rotational speed of the pump 22 is lowered to the minimum, the mode A1 is changed to the mode “A0-2”. The transition condition further includes the “outside air fan rotation speed lower limit” shown in the figure. However, as described above, in the mode A1, the fan 23 is operated at a constant minimum rotation speed. Not required.

  In addition, the transition condition from the mode “A0-2” to the mode “A0-1” is substantially “SA temperature <SA set value”. Note that the “apparatus” determination condition shown in the figure is only a confirming meaning and not essential, as in the case of the transition condition from the mode “A0-1” to the mode “A0-2”.

  The operation contents and mode transition in each mode described above will be briefly described below. In the following explanation, the outside air temperature rises from the state where the outside air temperature is low, and therefore the indirect outside air cooler is in the single operation mode. It is assumed that the outside air temperature will decrease afterwards.

  While the outside air temperature is low and the temperature of the supply air SA can be maintained at the set temperature only with the indirect outside air cooler, the indirect outside air cooler is set to the single operation mode, and the rotation speed of the pump 22 and the fan 23 of the outside air unit 20 is set. By controlling this, the temperature of the supply air SA is maintained near the set value.

  When the outside air temperature becomes high and the SA temperature cannot be maintained at the set temperature even when the rotation speed of both the pump 22 and the fan 23 of the outside air unit 20 is maximized, that is, even when the indirect outside air cooler is operated at the maximum capacity. (SA temperature> SA set value), the snow / ice cold water cooler is started, and the indirect outside air cooler and the snow / ice cold water cooler are switched to the combined operation mode. During this combined operation mode, for example, the indirect outdoor air cooler is always operated at the maximum capacity, and the snow and ice cold water cooler is controlled to maintain the SA temperature near the set value by controlling the valve opening degree of the cold water three-way valve 32. .

  If the outside air temperature further increases and the outside air temperature exceeds the return air temperature, the outside air cooling is counterproductive, so the indirect outside air cooler is shut down. For example, the pump 22 and the fan 23 are stopped. Thereby, it shifts to the single operation mode of the snow and ice cold water cooler. The snow and ice chilled water cooler maintains the SA temperature near the set value by continuously controlling the valve opening of the chilled water three-way valve 32 as in the combined operation mode.

  If the outside air temperature becomes low and the outside air temperature falls below the return air temperature during the single operation mode of the snow and ice cold water cooler, the indirect outside air cooler is operated again. This activates, for example, the pump 22 and the fan 23. As a result, the combined operation mode is again entered.

  Further, when the outside air temperature becomes lower and the supply air temperature (SA temperature) becomes too low when chilled water is passed through the chilled water coil (heat exchanger 12), the operation of the snow / ice chilled water cooler is stopped. This stops the cold water pump 31, for example. Alternatively, the valve opening on the cold water coil side in the cold water three-way valve 32 is fully closed (valve opening = 0%) so that cold water does not flow through the cold water coil.

  As a result, the indirect outside air cooler is again set to the single operation mode, for example, the mode A2 is initially set, and the rotation speed of the fan 23 of the outside air unit 20 is controlled to maintain the supply air temperature near the set temperature.

  If the outside air temperature further decreases and the supply air temperature becomes too low even if the rotation speed of the fan 23 of the outside air unit 20 is minimized, the rotation speed of the pump 22 of the outside air unit 20 is controlled next. The supply air temperature is maintained near the set temperature (mode A1).

  If the outside air temperature further decreases and the supply air temperature becomes too low even if the rotation speed of the pump 22 of the outside air unit 20 is minimized, the rotation speed of the pump 22 is kept at the minimum and the fan 23 is turned on / off. Maintain the supply air temperature at the set temperature while OFF (intermittent operation) (mode “A0-2”).

  If the outside air temperature further decreases and the supply air temperature becomes too low even if the fan 23 is turned on / off, the fan 23 is stopped and the supply air temperature is maintained at the set temperature by turning on / off the pump 22 (mode “ A0-1 ”).

  The “outside air temperature exceeds the return air temperature” and “outside air temperature falls below the return air temperature” may include some margin. That is, “the outside air temperature exceeds the return air temperature” is not limited to “outside air temperature> return air temperature”, and may be “outside air temperature> return air temperature−γ”, for example. When “outside air temperature> return air temperature−γ”, the indirect outside air cooler may be stopped early with a margin of γ ° C. when the outside air temperature has not yet reached the return air temperature. it can. Note that γ ° C. is, for example, about 2 ° C., but is not limited to this example.

  Similarly, “the outside air temperature is lower than the return air temperature” is not limited to “outside air temperature <return air temperature”, and may be, for example, “outside air temperature <return air temperature + ε”. In the case of “outside temperature <return air temperature + ε”, assuming that the outside air temperature is decreasing from a high state, at the stage where the outside temperature has not yet fallen below the return air temperature, only ε ° C. The indirect outside air cooler can be restarted early with a margin. Note that ε ° C. is, for example, about 2 ° C., but is not limited to this example.

  It is considered that it is more reasonable to stop and restart earlier with a margin of about 2 ° C. in view of the pump power of the indirect outside air cooler as described above. In actual operation, for example, when “outside air temperature> return air temperature−γ” is used for determining whether to stop the indirect outside air cooler, for example, “outside temperature < Although it is necessary to adjust the control so that no contradiction occurs in the control by setting the return air temperature to γ ”or the like, this is a design matter and is not particularly described here.

  Further, for example, a two-way valve may be used in place of the cold water three-way valve 32 to control the flow rate of cold water to the cold water coil. In this case, the flow resistance of the chilled water changes depending on the opening of the two-way valve. Therefore, when chilled water is supplied to a plurality of air conditioners with one chilled water pump, There is a possibility that a problem that the amount of cold water supplied to another air conditioner easily changes due to the change in the opening degree.

  The control device 40 includes, for example, an arithmetic processor such as a CPU / MPU, a storage unit such as a memory, an input / output interface, and the like. A predetermined application program is stored in the storage unit in advance. When the arithmetic processor executes this application program, for example, the processing described in FIG. 2, FIG. 3, FIG.

The snow and ice utilizing air conditioning system of the present example can also be described as follows, for example.
The snow and ice-use air conditioning system of this example has an outside air cooler that cools the return air RA, which is return air from the air-conditioning target space (server room, data center, etc.), using outside air. The outside air cooler is an indirect outside air cooler in the above example, but is not limited to this example, and may be a direct outside air cooler. As described with reference to FIG. 1, the indirect outside air cooler is an air conditioner that performs heat exchange between the outside air OA and the return air RA indirectly through a refrigerant. On the other hand, the direct outside air cooler supplies the outside air OA to, for example, the air-conditioning target space, although the configuration and the like are not particularly illustrated. Since both the indirect outside air cooler and the direct outside air cooler have existing configurations, they will not be described in further detail.

The snow / ice utilization air conditioning system of the present example further includes a snow / ice cold water cooler.
The snow and ice cold water cooler, for example, heats the return air and the cold water when the cold water is supplied, and a cold water pipe and a first pump for supplying cold water generated by the snow mountain to the first heat exchanger. The first heat exchanger to be replaced is included.

An example of this cold water pipe is the cold water pipe 33 of FIG. 1, and an example of this first pump is the cold water pump 31 of FIG. An example of the first heat exchanger is the heat exchanger 12 of FIG.
The snow and ice utilization air conditioning system of this example further includes a control device.

  The control device includes, for example, a first mode in which the outside air cooler is operated alone, a second mode in which the outside air cooler and the snow and ice cold water cooler are operated in combination, and a third mode in which the snow and ice cold water cooler is operated alone. The outside air cooler and the snow / ice cold water cooler are controlled using each mode. An example of this control device is the control device 40.

  Further, an example of the first mode is the mode (1) described in FIG. 2 etc. (outside air cooling single operation), and an example of the second mode is the mode (2) (“outside air cooling + cold water cooling (combined use) Operation) ”, and an example of the third mode is the mode (3) (cold water cooling single operation).

An example of the outside air cooler is an indirect outside air cooler as described above.
The indirect outside air cooler includes, for example, a second heat exchanger that exchanges heat between the outside air OA and the refrigerant, and a third heat exchanger that exchanges heat between the return air RA that is return air from the air-conditioning target space and the refrigerant. The second heat exchanger and the third heat exchanger have a pipe and a second pump for circulating the refrigerant.

  An example of the first heat exchanger is the sensible heat exchanger 21 shown in FIG. 1, and an example of the third heat exchanger is the sensible heat exchanger 11 shown in FIG. One example of the pipe and the second pump is the pipe 14 and the pump 22 shown in FIG.

  The return air RA is configured to first pass through the third heat exchanger and then pass through the first heat exchanger. Then, the air after passing through the first heat exchanger is supplied to the air-conditioning target space as the supply air SA.

  When both the indirect outdoor air cooler and the snow and ice cold water cooler are in operation (if functioning), the return air RA is first cooled by the third heat exchanger and then the second The air supply SA is further cooled by one heat exchanger. That is, the first heat exchanger is provided on the downstream side of the air (return air) flow with respect to the third heat exchanger.

  When the indirect outside air cooler is in a single operation state, the supply air SA is substantially the one in which the return air RA is cooled by the third heat exchanger. When the snow and ice cold water cooler is in the single operation state, the return air RA is substantially cooled by the first heat exchanger without being cooled by the third heat exchanger, and becomes the supply air SA. It will be.

  For example, when the controller 40 cannot maintain the temperature of the supply air SA (supply air temperature) at a set value even when operating at the maximum cooling capacity of the indirect outside air cooler during operation in the first mode, Control to switch to the second mode is performed. In the example of FIG. 1, the supply air temperature is measured by the supply air temperature sensor 15.

  For example, when the outside air temperature exceeds the return air temperature during operation in the second mode, the control device 40 performs control to stop the operation of the indirect outside air cooler and shift to the third mode. In the example of FIG. 1, the outside air temperature is measured by the outside air temperature sensor 24, and the return air temperature is measured by the return air temperature sensor 16.

  For example, when the outside air temperature falls below the return air temperature during operation in the third mode, the control device 40 performs control to resume operation of the indirect outside air cooler and shift to the second mode. .

  For example, the control device 40 stops the cold water supply to the first heat exchanger during operation in the first mode. As an example, this is realized by setting the valve opening degree of the cold water three-way valve 32 to the first heat exchanger side to 0% (the valve is completely closed). 31 may be stopped. The cold water three-way valve 32 is an example of a three-way valve for adjusting the amount of cold water supplied to the first heat exchanger. However, as described above, not only the three-way valve but also a two-way valve or the like may be used.

For example, during operation in the second mode or the third mode, the control device 40 controls the three-way valve to adjust the amount of cold water supplied to the first heat exchanger so that the supply air temperature becomes the set temperature. .
For example, during operation in the first mode, the control device 40 controls the rotation speed of the second pump or the rotation speed of the fan 23 so that the supply air temperature becomes the set temperature. The fan 23 is a fan for supplying outside air OA to the first heat exchanger.

  In the first mode, for example, the A1 mode which is a mode in which the fan 23 is kept at a constant minimum rotational speed and the rotational speed of the second pump is controlled, and the second pump is kept in a constant maximum rotational speed and the rotational speed of the fan. It may have an A2 mode for controlling. And you may comprise so that the control apparatus 40 may control driving | operation by any one mode of this A1 mode and A2 mode. An example of the A1 mode is the mode A1, and an example of the A2 mode is the mode A2.

Then, for example, during operation in the A1 mode, the control device 40 performs control to shift to the A2 mode when the supply air temperature exceeds the set temperature even when the rotation speed of the second pump is maximized.
Further, for example, during operation in the A2 mode, the control device 40 performs control to shift to the second mode when the supply air temperature exceeds the set temperature even if the rotation speed of the fan 23 is maximized.

In addition, for example, when the supply air temperature is lower than the set temperature even when the amount of cold water supplied to the first heat exchanger is zero during operation in the second mode, the control device 40 performs control to shift to the A2 mode. Do.
As described above, according to the snow-ice-use air conditioning system of this example, etc., it is an air-conditioning system that uses snow-ice, and is composed of an indirect outside air cooler and a snow-ice cold water cooler without using a refrigerator. Provide air conditioning systems with high energy-saving effects. Furthermore, it is possible to obtain a higher energy saving effect by particularly efficiently operating the indirect outdoor air cooler and the snow / ice cold water cooler. Depending on environmental changes, for example, when operating an indirect outside air cooler alone, depending on the outside air temperature, etc., when operating a snow and ice cold water cooler alone, and using both an indirect outside air cooler and a snow and ice cold water cooler High energy-saving effect can be obtained by properly using different cases.

  Alternatively, for example, by providing a more detailed mode, such as the A1 mode, the A2 mode, etc., and performing mode transition control according to the detailed mode, the supply air temperature is maintained at a set value and higher. Appropriate operation can be performed to obtain an energy saving effect.

10 Inside Air Unit 11 Sensible Heat Exchanger 12 Heat Exchanger 13 Fan 14 Piping 15 Supply Air Temperature Sensor 16 Return Air Temperature Sensor 20 Outside Air Unit 21 Sensible Heat Exchanger 22 Pump 23 Fan 24 Outside Air Temperature Sensor 31 Cold Water Pump 32 Cold Water Three-way Valve 33 Cold water pipe 40 control device

Claims (12)

An indirect outdoor air cooler for cooling the return air, which is return air from the air-conditioned space, using outside air;
The return air, a snow and ice cold water air cooler for cooling using cold water generated by snowy mountains, and cold water pipe and the first pump for supplying the cold water to the first heat exchanger, the cold water A snow and ice cold water cooler having the first heat exchanger that exchanges heat between the return air after passing through the indirect outside air cooler and the cold water,
A controller for controlling the indirect outside air cooler and the snow and ice cold water cooler ;
The control device includes a first mode of operating the indirect outdoor air cooling machine alone, and a second mode for combined operation of the snow and ice cold water cooling device and the indirect outdoor air cooling machine to operate the snow and ice cold water cooling machine alone Using each mode of the third mode, the indirect outside air cooler and the snow / ice cold water cooler are controlled , and in the control using the second mode, the indirect outside air cooler is operated at a maximum cooling capacity, and The snow / ice use air conditioning system is characterized in that the amount of cold water supplied to the first heat exchanger of the snow / ice cold water cooler is adjusted to an arbitrary ratio . The indirect outside air cooler includes a second heat exchanger that exchanges heat between the outside air and a refrigerant, a third heat exchanger that exchanges heat between the return air and the refrigerant, the second heat exchanger, and the second heat exchanger. A pipe for circulating the refrigerant in the three heat exchangers and a second pump, and a fan for taking in the outside air and supplying it to the second heat exchanger;
The control device performs control in the first mode when the temperature of the outside air is so low that the cooling capacity of the indirect outside air cooler exceeds the required cooling capacity for the air-conditioning target space, and the temperature of the outside air increases as the temperature of the outside air increases. 2. The snow and ice-use air conditioning system according to claim 1, wherein the system is switched in order between the second mode and the third mode. The air after passing through the first heat exchanger is supplied to the air conditioning target space as supply air,
A supply air temperature measuring means for measuring the temperature of the supply air;
The control device performs control to switch to the second mode when the supply air temperature cannot be maintained at a set value even when operating at the maximum cooling capacity of the indirect outside air cooler during operation in the first mode. The snow-ice-use air conditioning system according to claim 1 or 2, characterized by the above. Outside temperature measuring means for measuring the temperature of the outside air;
It further has a return air temperature measuring means for measuring the temperature of the return air,
When the outside air temperature exceeds the return air temperature during operation in the second mode, the control device performs control to stop the indirect outside air cooler and shift to the third mode. The snow-ice-use air conditioning system according to claim 3, When the outside air temperature falls below the return air temperature during operation in the third mode, the control device performs control to resume operation of the indirect outside air cooler and shift to the second mode. The snow-ice-use air conditioning system according to claim 4, Wherein the control device, wherein in during operation first mode, snow ice use air-conditioning system according to any one of claims 1 to 3, characterized in that to stop the cold water supply of the to the first heat exchanger. The air after passing through the first heat exchanger is supplied to the air conditioning target space as supply air,
A supply air temperature measuring means for measuring the temperature of the supply air;
The snow and ice cold water cooler further includes a three-way valve for adjusting the amount of cold water supplied to the first heat exchanger,
During operation in the second mode or the third mode, the control device controls the three-way valve so that the amount of cold water supplied to the first heat exchanger is adjusted so that the supply air temperature becomes a set temperature. The snow and ice-use air conditioning system according to claim 1, wherein the air conditioning system is adjusted. Before SL air after passing through the first heat exchanger is supplied to the space to be air-conditioned as supply air,
It has a supply air temperature measurement means to measure the temperature of the air supply,
2. The control device according to claim 1, wherein during the operation in the first mode, the control device controls the rotation speed of the second pump or the rotation speed of the fan so that the supply air temperature becomes a set temperature. 2. The snow and ice utilization air conditioning system according to 2. The first mode is an A1 mode in which the fan is kept at a constant minimum rotational speed and the rotational speed of the second pump is controlled, and the second pump is kept at a maximum rotational speed and the rotational speed of the fan. A2 mode to control
The snow and ice-use air conditioning system according to claim 8 , wherein the control device may control the operation in any one of the A1 mode and the A2 mode. The control device performs control to shift to the A2 mode when the supply air temperature exceeds a set temperature even when the rotation speed of the second pump is maximized during operation in the A1 mode. The snow-ice-use air conditioning system according to claim 9 . The control device performs control to shift to the second mode when the supply air temperature exceeds a set temperature even when the rotation speed of the fan is maximized during operation in the A2 mode. The snow and ice utilization air conditioning system according to claim 9 . The control device performs control to shift to the A2 mode when the supply air temperature is lower than a set temperature even when the amount of cold water supplied to the first heat exchanger is zero during operation in the second mode. The snow-ice-use air conditioning system according to claim 9, wherein the system is performed.