JP3220286B2 - Operating method of heat source system for environmental test room - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat source system for an environmental test room, and more particularly to a method for operating a heat source system for an environmental test room using both a direct expansion coil and a water-cooled coil.

[0002]

2. Description of the Related Art An environmental test room is one of air conditioners for performing a simulation under a natural or specially set environment used for an automobile performance test and the like, and is intended for an environmental test for an industry. Things. Such an environmental test room is operated in a high-temperature cycle for reproducing summer weather, a low-temperature cycle for reproducing winter weather, and a medium-temperature cycle for reproducing intermediate weather in distinction from a normal temperature field.

By the way, as a heat source system for reproducing the environment of various temperature conditions as described above in an environmental test room,
Conventionally, two systems, a direct expansion system and a brine system, have been adopted.

First, the direct expansion system is a system in which all conditions from a low temperature range to a high temperature range are realized by a direct expansion coil for circulating a refrigerant. This direct expansion method uses no intermediate heat medium, has a quick start-up, has excellent responsiveness, has a small loss at the time of heat exchange, can be soaked to -40 ° C, and, above all, has a low level of simplicity. Although there are many advantages such as the ability to build a price system, on the other hand, controllability is poor, wide-range temperature control cannot be performed, and especially in the high temperature range, it is difficult to control the evaporation temperature,
It has weaknesses such as weakness in load fluctuation.

[0005] Next, the brine method is a method in which brine having a concentration that can be used even in a low temperature range is selected, and all conditions from a low temperature range to a high temperature range are cooled through the brine. Although this brine system has a slow start-up, it has good controllability from low temperature range to high temperature range, and has many advantages such as strong load fluctuation.However, since a brine circulation system needs to be added, the system becomes more complicated, Power for transporting the brine is required, and particularly in a low temperature region, a very large power is required. Further, there are many problems such as that there are few brines exhibiting stable performance over the entire range from a low temperature range to a high temperature range, or that management of the concentration, corrosiveness, decay, toxicity, and flammability of the brine itself is troublesome.

[0006]

As described above,
In the conventional method, there is no heat source system for an environmental test room that exhibits good controllability in the entire range from a low temperature range to a high temperature range, and at the same time is easy to maintain. Alternatively, in the conventional method, the energy-saving operation cannot be performed in the case of the high-temperature cycle or the outside air condition.

[0007] The present invention has been made in view of the problems of such a conventional system, and therefore aims at excellent controllability from low to high temperatures and easy maintenance. It is an object of the present invention to provide a new and improved method of operating a heat source system for an environmental test room capable of performing energy saving operation.

[0008]

According to a first aspect of the present invention, there is provided an air conditioner having a direct expansion coil and a water-cooled coil for performing air conditioning in an environmental test chamber; A refrigerator selectively communicating with the direct expansion coil of the air conditioner to circulate a refrigerant; selectively communicating with the refrigerator to circulate cooling water and selectively communicating with a water cooling coil of the air conditioner. An environmental test comprising: a cooling tower that circulates cooling water; and a heat exchanger that selectively communicates with the refrigerator to circulate refrigerant and selectively communicates with a water cooling coil of the air conditioner to circulate cold water. In the room heat source system: at the time of the low-temperature cycle, the direct expansion coil and the refrigerator are connected to circulate the refrigerant, and the cooling tower is connected to the refrigerator to circulate the cooling water; The water cooling coil communicates with the heat exchanger to circulate cold water, the heat exchanger communicates with the refrigerator and circulates refrigerant, and the refrigerator communicates with the cooling tower to circulate cooling water. A method of operating a heat source system for an environmental laboratory is provided.

Further, according to the second aspect, at the time of a high-temperature cycle or at the time of a medium-high temperature cycle in which the outside air temperature is lower than the room temperature of the environmental test chamber, the water cooling coil is communicated with the cooling tower to circulate the cooling water. Accordingly, it is preferable to operate the heat source system for an environmental test room in an energy-saving manner.

According to a third aspect of the present invention, a direct expansion type external conditioner is provided for selectively communicating with the air conditioner, and the air conditioner and the direct expansion type external conditioner are required when dehumidification is required. And operating the heat source system for an environmental test room by introducing outside air through the direct expansion type external conditioner and removing moisture contained in the outside air.

According to another aspect of the present invention, the water cooling coil is a vertical coil having an upper header and a lower header, and the upper header selectively communicates with an air blow source or a cooling water return system. The lower header is selectively communicated with a drain or a cooling water feed system.During a drain cycle, the upper header communicates with the air blow source, and the lower header communicates with the drain. An airflow is passed from the side to the lower header side via the vertical coil, and when the water-cooling coil operates, the lower header communicates with the cooling water feed system and the upper header communicates with the cooling water return system. By flowing cooling water from the lower header side to the upper header side via the vertical coil, the heat source for the environmental test chamber It is preferable to operate the system.

[0012]

According to the first aspect, since the low-temperature region is operated by the direct expansion system and the middle and high-temperature region is operated by the water-cooling system, the entire range from the low-temperature region to the high-temperature region has excellent startup and responsiveness. Control can be performed. Particularly in a low temperature region, direct cooling is possible by the direct expansion method, so that an effective operation can be performed. In the direct expansion method, the dew point temperature of the device is 20 ° C.
However, according to the present invention, the dew point temperature of the apparatus can be increased, for example, since the apparatus can be operated in a cold water mode at 15 ° C. or higher. Further, since no brine is used, no maintenance and management of the brine is required at all, and a high-lift pump is not required even during a low-temperature cycle.

According to the second aspect of the present invention, the cooling tower has a cooling capacity during a high-temperature cycle or a middle-high temperature cycle in which the outside air temperature is lower than the room temperature in the environmental test chamber. Can be implemented.

According to the third aspect, even in the case of operation in a low temperature range, it is possible to introduce the outside air dehumidified by the direct expansion type cooling coil of the external conditioner, so that maintenance is difficult and an expensive dehumidifier is used. Need not be installed. In the case of low-temperature operation, since the air conditioner of the main unit is operated by the direct expansion coil, it is possible to remove moisture that has not been treated by the external controller by the direct expansion coil of the main unit.

According to the fourth aspect of the present invention, even in the case of operating with a direct expansion coil in a low temperature range, complete drainage is achieved by previously flowing an airflow from the upper header side to the lower header side via the vertical coil. Therefore, freezing of the water-cooled coil can be prevented.

[0016]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First, the configuration of a heat source system for an environmental test room to which the method of the present invention can be applied will be described with reference to FIGS. 1 is a flow sheet of the entire heat source system, and FIG. 2 is a flow sheet of a water system of the heat source system.

As shown in FIG. 1, an environmental test chamber heat source system 1 to which the method of the present invention can be applied includes an environmental test chamber 4 having an air supply port 2 and an exhaust port 3, an air conditioner 5, and a refrigeration system. , A cooling tower 7, and a heat exchanger 8,
Further, an external conditioner 9 for taking in outside air is provided.

The air conditioner 5 includes a direct expansion coil 1 from the upstream side.
0, a water-cooling coil 11, a heating device 12, a humidifying device 13, and a blower 14. The air sent from the external conditioner 9 or the exhaust port 3 through the pipe 15 is adjusted according to conditions. It is possible to feed into the environmental test chamber 4 via the path 16. The external air conditioner 9 has an external air intake 17, a direct expansion coil 18 and a blower 19 arranged from the upstream side, and has a direct expansion coil 1 via a circulation system 20 as described later.
By circulating the refrigerant through 8, it is possible to remove the moisture contained in the air introduced from the outside air intake 17 and send it out from the pipe 15.

The direct expansion coil 18 of the air conditioner 5 is
And, it communicates with the refrigerator 6 through the pipe line 22 to form a circulation system of the refrigerant. The water cooling coil 11 of the air conditioner 5 communicates with the heat exchanger 8 via a pipe 23 and a pipe 24, and further communicates with the cooling tower 7 via a pipe 25 and a pipe 26. , A cooling water circulation system is formed between the water cooling coil 11 and the heat exchanger 8 or the cooling tower 7.

Further, an air source 27 and a drain passage 28 are connected to the water cooling coil 11 of the air conditioner 5, and as described later, when there is a possibility that the water cooling coil 11 freezes at a low temperature, the air source 27 The water in the coil can be drained by the coil blow system including the drain path 28. In addition, tank 29
Is connected, and it is possible to collect the drained water retained in the coil. In the above example, the water-cooled coil 11
Although the problem of freezing is solved by a coil blow system, as an alternative method, it is possible to prevent the freezing by mixing an antifreeze into the cooling water system.

The refrigerator 6 communicates with the cooling tower 7 via a pipe 30 and a pipe 31 to form a refrigerant circulation system. Furthermore, the refrigerator 6 is connected to the pipes 32 and 33
Through the cooling tower 7 to form a cooling water circulation system.

The present invention is applicable to the operation of the environmental test room heat source system having the above-described configuration.
Next, in order to facilitate understanding of the method of the present invention, an embodiment in which the method of the present invention is applied to the illustrated heat source system for an environmental test room will be described for each operation mode.

1. Low-temperature cycle In order to realize a low-temperature environment such as in winter, the refrigerant is circulated through the direct expansion coil 10, the pipe 21, the refrigerator 6, and the pipe 22, and the refrigerant cooled by the refrigerator 6 directly air-cools. Can be cooled. As a result, it is possible to perform control with fast rise and quick response.

Since the heat source system 1 for the environmental test uses the water-cooled coil 11 in addition to the direct expansion coil 10,
When the heat source system 1 is operated at a low temperature cycle, freezing of water in the water cooling coil 11 becomes a problem. However, this can be dealt with in accordance with the invention by means of the coil blow system described below in connection with FIG. Alternatively, it is also possible to mix antifreeze into the cooling water system shown in FIG. In this case, there is no need for a high head pump as in the brine type.

In the low-temperature cycle operation, it is necessary to remove moisture from the introduced outside air. According to the present invention, it is possible to remove moisture from the taken-in outside air by using the outside conditioner 9 as described later. This eliminates the need for expensive dehumidifiers that are difficult to maintain and possible.

2. Medium-high temperature cycle In the operation using the direct expansion coil as described above, it is impossible for the device dew point temperature to exceed 20 ° C. According to the method of the present invention, a water cooling system using a water cooling coil is adopted. For this purpose, first, a cooling water circulation system is formed by the water cooling coil 11, the pipe 24, the heat exchanger 8 and the pipe 23, and the refrigerant circulation system is formed by the heat exchanger 8, the pipe 30, the refrigerator 8 and the pipe 31. Is formed. at the same time,
The refrigerator 8, the pipe 32, the cooling tower 7, and the pipe 33 form a cooling water circulation system.

As a result, the refrigerant appropriately cooled by the cooling tower 7 and the refrigerator 8 can be sent to the heat exchanger 8, and the chilled water circulating in the water cooling coil 11 can be cooled through the refrigerant. Will be possible. As described above, according to the present invention, since the water-cooling method is used in the middle and high temperature range, it is possible to perform an operation with high responsiveness, strong load fluctuation, and excellent controllability. Further, the method of the present invention does not use brine whose concentration, corrosiveness, putrefaction, toxicity, flammability and the like are difficult to control, so that the maintenance management of the cooling water system is easy.

3. Energy-Saving Cycle According to the method of the present invention, an energy-saving operation can be performed when the cooling water of the cooling tower is available, such as in the winter, even during a high-temperature cycle or a medium-temperature cycle. In this case, a cooling water circulation system is formed by the water cooling coil 11, the pipe 24, the pipe 25, the cooling tower 7, and the pipe 26, and the cooling water cooled by the outside air in the cooling tower 7 is directly sent to the water cooling coil 11. It becomes possible. As a result, the air can be cooled without using the refrigerator 6, so that the energy saving operation of the heat source system 1 can be performed.

Next, referring to FIGS. 3 to 5, the water cooling coil 11 used in the heat source system 1 to which the present invention can be applied.
Will be described. As described above, in the present heat source system 1, since the direct expansion coil 10 and the water-cooled coil 11 are used in combination, when the direct expansion coil 10 is used during the low-temperature cycle, the water retained in the water-cooled coil 11 is prevented from freezing. There is a need to. Therefore, according to the present invention, it is possible to employ the water-cooled coil 11 having the configuration shown in FIGS.

The water cooling coil includes a plurality of fins 40,
An upper header pipe 41, a lower header pipe 42, and a vertical pipe 43 communicating the upper header pipe 41 and the lower header pipe 42.
It is composed of

The upper header pipe 41 communicates with the air source 44 via a solenoid valve V3 for blowing through a pipe 42, and communicates with a cooling water return path 48 via a switching valve V1 and a switching valve 47 via a pipe 45. are doing.

The lower header pipe 42 communicates with a drain pipe 51 through a pipe 49 through a blow solenoid valve V4. Although not shown in FIG. 3 and FIG.
1 may be configured to communicate with a tank 29 as shown in FIGS. Furthermore, the lower header pipe 42 communicates with a cooling water supply path 54 via a switching valve V2 through a pipe 52. As shown in FIG. 4, the switching valves V1, V2, V3, and V4 can each be opened and closed by a controller 55, and the switching valve 47 can be opened and closed by a temperature sensor 56.

When a normal water-cooling operation is performed by the water-cooling coil 11 having such a structure, as shown in FIG.
1 and V2 are opened, and the switching valves V3 and V4 are closed, so that the cooling water can flow from the lower header side to the upper header side through the vertical pipe 43, and the water cooling operation is performed by such an operation. Is performed.

On the other hand, when the cooling water in the water cooling coil 11 is drained in order to perform the low temperature cycle operation by the direct expansion coil 10, as shown in FIG. 5, the switching valves V1 and V2 are closed and the cooling is performed. The supply of water is stopped, and the switching valves V3 and V4 are opened to allow the air blow to flow from the upper header through the vertical pipe 43 to the lower header, thereby cooling the water cooling pump 11 through the pipe 49. It is possible to completely drain the water. Also, the switching valve V3
May be intermittently opened and closed by a combination of a timer and a pulse operation.

With the above-described configuration, according to the present invention, the cooling water in the water-cooled coil 11 can be completely drained before the low-temperature cycle operation by the direct expansion coil 10 is performed. Eliminates the need.

Finally, a method of treating outside air in the system according to the present invention will be briefly described. In general, in order to maintain a low-temperature test room, it is necessary to cope with the heat load generated inside and to treat the intake outside air. In particular, in the treatment of the intake outside air, a dehumidifier was required in the conventional method. However, according to the method of the present invention, since the direct expansion coil 10 having the dehumidifying ability is employed as the main cooling coil, it is not necessary to provide a dehumidifier.

However, if the main cooling coil bears all the moisture of the taken-in outside air, the surface of the coil freezes, and there is a possibility that a long-time continuous operation cannot be performed. Therefore, in the method of the present invention, the external air taken in by the external air conditioner 9 is subjected to primary processing to reduce the load on the main cooling coil. As a result, for example, a system capable of continuous operation for more than 48 hours can be constructed.

In this case, the blowing temperature is set to a temperature at which freezing does not occur, so that the surface of the direct expansion coil of the external conditioner 9 does not freeze.
For example, by setting the temperature at about 7 ° C., continuous operation of the external conditioner 9 is also possible. Furthermore, the thickness of the frost adhering to the fins has a distribution as shown in FIG. 6 with respect to the evaporation temperature, so that the water dehumidifying ability of the main cooling coil is adjusted as desired by changing the fin pitch of the coil. be able to. As described above, according to the method of the present invention, stable continuous operation is possible without switching between defrost operation and normal operation.

[0039]

As described above, according to the present invention,
Cooling is performed by the direct expansion coil in the low temperature range, and cooling is performed by the water cooling coil in the middle and high temperature range, so that a heat source system with excellent controllability over the entire temperature range can be provided, and maintenance is performed because no brine is used. A heat source system that can be easily managed can be provided.

Further, according to the present invention, the water-cooling coil can be cooled by the cooling tower without using the refrigerator during the high-temperature cycle operation or when the outside air condition is low. It is possible.

Further, according to the present invention, since the water contained in the taken-in outside air can be removed in advance by the external conditioner using the direct expansion coil, it is not necessary to add an expensive dehumidifier which is difficult to maintain and expensive. .

Furthermore, according to the present invention, since the cooling water in the water-cooling coil can be easily and completely removed, the cooling in the water-cooling coil can be performed even when the low-temperature cycle operation is performed by the direct expansion coil. There is no need to worry about freezing the water.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a whole heat source system for an environmental laboratory to which a method according to the present invention can be applied.

FIG. 2 is a flow sheet of a water system of the heat source system for an environmental test chamber in FIG. 1;

FIG. 3 is a sketch of a water-cooled coil to which the present invention can be applied.

FIG. 4 is a schematic flow sheet of the water-cooled coil of FIG. 3;

FIG. 5 is a table showing an open / closed state of a valve of the water cooling coil of FIG. 3;

FIG. 6 is a graph showing the relationship between the amount of frost adhering to the fins of the direct expansion coil to which the present invention can be applied and the evaporation temperature.

[Explanation of symbols]

 Reference Signs List 1 heat source system for environmental test room 4 environmental test room 5 air conditioner 6 refrigerator 7 cooling tower 8 heat exchanger 9 external controller 10 direct expansion coil 11 water cooling coil

Claims (4)

(57) [Claims] An air conditioner having a direct expansion coil and a water-cooled coil for air conditioning in an environmental test chamber; and a refrigerator selectively communicating with the direct expansion coil of the air conditioner to circulate a refrigerant. A cooling tower that selectively communicates with the refrigerator to circulate cooling water and selectively communicates with a water cooling coil of the air conditioner to circulate cooling water; a refrigerant that selectively communicates with the refrigerator. And a heat exchanger for selectively communicating with a water cooling coil of the air conditioner to circulate cold water. In the heat source system for an environmental test room, the direct expansion coil and the refrigerator are arranged at the time of a low-temperature cycle. And circulates the refrigerant, and communicates the cooling tower and the refrigerator to circulate the cooling water; during the medium-high temperature cycle, communicates the water cooling coil and the heat exchanger to circulate the cold water, With circulating refrigerant communicates with the exchanger and the refrigerator, the refrigerator and said cooling tower is communicated with cooling water circulating; method of operating a heat source system for environmental test chamber, characterized in that. 2. The method according to claim 1, wherein the water cooling coil is connected to the cooling tower to circulate cooling water during a high-temperature cycle or a medium-high temperature cycle in which the outside air temperature is lower than the room temperature of the environmental test chamber. The method for operating the heat source system for an environmental test room according to claim 1. 3. A direct expansion type external conditioner which selectively communicates with the air conditioner, and when the dehumidification is required, the air conditioner and the direct expansion type external conditioner are communicated with each other. The method for operating a heat source system for an environmental test room according to claim 1, wherein outside air is introduced through a direct expansion type external conditioner to remove moisture contained in the outside air. 4. The water-cooled coil is a vertical coil having an upper header and a lower header. The upper header is selectively connected to an air blow source or a cooling water return system, and the lower header is selectively connected to a cooling water return system. In the drainage cycle, the upper header communicates with the air blow source, and the lower header communicates with the drainage port. An air flow is circulated to the lower header side via the lower header side when the water cooling coil operates, while the lower header communicates with the cooling water feed system, and the upper header communicates with the cooling water return system. 4. The cooling water is circulated to the upper header side through the vertical coil through the vertical coil. The method of operating a heat source system for environmental testing chamber.