JPH0719523A - Natural cooling air conditioner - Google Patents

Abstract

PURPOSE:To improve energy saving effect and permit the securing of reliability on operation by a method wherein an indoor machine is provided with a fore stage heat exchanger and a rear stage heat exchanger while water circulating systems are formed so that the rear stage side can be operated by a refrigerating machine at all times and the fore stage side can be operated by switching between the refrigerating machine and a cooling tower. CONSTITUTION:An air-conditioning machine 1 is provided with a fore stage side circulating coil 1a and a rear stage side circulating coil 1b while a water circulating system, connected to cooling water pipelines 6, 7, is formed so that the rear stage side circulating coil 1b can be operated by refrigerating machines 2, 3 at all times and another water circulating system, connected to cooling water pipelines 8, 9, is formed so that the fore stage side circulating coil 1a can be operated while switching between the refrigerating machines 2, 3 and cooling towers 4, 5. As a result, when the fore stage side circulating coil 1a is being operated by the cooling towers 4, 5, the rear stage side circulating coil 1b is being operated by the refrigerating machines 2, 3 while the insufficient cooling of the fore stage side circulating coil 1a can be absorbed by the rear stage side circulating coil 1b whereby free cooling can be effected in a season wherein an outside air temperature is unstable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a natural cooling air conditioner used in an electronic computer room or the like, which requires the indoor temperature to be kept constant at all times, and particularly, when the outdoor temperature becomes lower than the internal temperature. The present invention relates to a natural cooling air conditioner provided with a so-called free cooling system for effectively utilizing air conditioning.

[0002]

2. Description of the Related Art Since an electronic computer generates a large amount of heat during operation and is easily affected by heat, the indoor temperature must be kept constant in order to ensure stable operation and reliability of the computer. In addition, the air conditioning system needs to be operated continuously and continuously for a year. Therefore, the air conditioning system consumes a large amount of energy, and energy saving is an important issue.

Conventionally, as an energy saving measure, FIG.
As shown in FIG. 4 and FIG. 4, there is a natural cooling air conditioner including a so-called free cooling system that performs cooling operation using cooling water when the outdoor temperature becomes low, such as in winter.

The figure shows a system for centrally air-conditioning a building in which a computer room is on a plurality of floors. One is installed in a side room SR of a computer room DR on one floor, for example, the top floor.
Air conditioners 101, two refrigerators 10 installed in the basement
2, 103 and the two cooling towers 104, 105 installed on the rooftop constitute one unit.
In the air conditioner 101, one circulation coil 101A is arranged in a case, and a blower fan 101c is arranged below it. The blower fan 101c blows air through the duct 101d.
Is sent from the floor F to the computer room DR via the duct and is recovered from the return chamber C on the ceiling via the duct 101e. The circulation coil 101A is the refrigerator 102 or the refrigerator 10.
3, the water circulation system is formed so as to be operable. That is, the circulation coil 101A is connected to the cold water pipes 106 and 107, and the cold water pipes 106 and 107 are connected to the branched branch pipes 106A and 107A and the branch pipes 106a and 107a, which are the branch pipes 106A and 107A and the branch pipes. 10
Refrigerator 102 or refrigerator 103 via 6a and 107a
Are linked to. The refrigerator 102 and the refrigerator 103 respectively include cooling water pipes 110 and 111, a cooling water pipe 112,
113 is connected to the cooling water pipes 110, 111,
Cooling tower 1 via cooling water pipes 112, 113
05 and 104 of the condensing coil 105a, the condensing coil 104
It is connected to a. The cooling water pipes 110 and 111 are opened and closed by switching valves 110a and 111a, and the branch pipes 106A and 107A and the cooling water pipes 110 and 111 are also opened.
Bypass pipes 114 and 115 are connected between and, and are opened and closed by switching valves 114a and 115a.

This is a switching valve 1 for the bypass pipes 114 and 115 in the summer, when the outside temperature is high, or in the middle period.
The refrigerator 10 is operated by closing 14a and 115a.
2. Cold water from the refrigerator 103 is branched pipes 106A, 107
A, cold water pipe 106 through branch pipes 106a and 107a,
The condensing coils 104a and 10a of the cooling towers 104 and 105 are merged at 107 and circulate through the circulation coil 101A.
The cooling water from 5a is the cooling water piping 112, 11 respectively.
3. Circulate through the cooling water pipes 110 and 111.

On the other hand, in winter when the outdoor temperature is low,
Switching valves 110a, 11 of the cooling water pipes 110, 111
1a is closed and the switching valves 114a and 115a of the bypass pipes 114 and 115 are opened, and as shown by the thick line in FIG.
6a and 107a to the cold water pipes 106 and 107 to circulate the circulation coil 101A, while the cooling water from the condenser coil 105a of the cooling tower 105 flows to the bypass pipes 114 and 115 through the cooling water pipes 110 and 111, and the branch pipe 106A, 107A to cold water pipes 106, 1
07 and circulates in the circulation coil 101A.

As described above, in the winter or the like when the outside temperature is low, the switching valves 114a and 115a are opened, and the cold water from the refrigerator 103 and the cooling water from the condenser coil 105a of the cooling tower 105 are combined to circulate the circulation coil 10.
Cooling is performed by circulating 1A. That is, cooling is performed together with free cooling by cooling water. In this case, in order to set the temperature of the underfloor F of the computer room DR to the optimum temperature of 19 degrees, the circulation coil 101A
It is necessary that the outlet temperature of the condenser tower 105a of the cooling tower 105 is 7 to 9 degrees.
Similarly, the outlet temperature must be 7 to 9 degrees. Therefore, even when the outside temperature is low, such as in winter, when the outside temperature is high during the daytime and the temperature is unstable, it is not possible to perform cooling by free cooling.
Switching between 14a and 115a is required. However,
Since the uncertainties of the outside temperature must be judged, and it is difficult to perform an accurate switching operation, the temperature of the day is the optimum temperature for free cooling at all times.
The actual situation is that the valves 114a and 115a are switched several times in one season by selecting a date and time when the temperature is stable from 9 to 9 degrees. However, since the outside air temperature is stable for a short period, the start time of free cooling is late, the end time is early, and the free cooling execution period is short, so the energy saving effect cannot be sufficiently exerted. .

Moreover, since the cooling operation is stopped when switching the switching valves 114a and 115a, the computer room D
There is a problem that reliability at the time of switching such as an increase in the temperature of the R underfloor F occurs and the reliability is impaired.

[0009]

The problem to be solved is that the period for performing free cooling is short, and
This is a point that lacks reliability when switching.

[0010]

According to the present invention, an indoor unit is provided with front and rear heat exchangers, and the rear heat exchanger performs chilled water operation by a refrigerator while the front heat exchanger is operated. The most important feature of the container is that it switches between cold water operation by the refrigerator and cooling water operation by the cooling tower. As a result, we have extended the free-cooling execution period and improved reliability during switching.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show one embodiment of the present invention, in which FIG.
FIG. 2 is an overall configuration diagram of the unit, and FIG. 2 is an overall configuration diagram of one unit showing an operating state when the outside air temperature is low.

The figure shows a system for centrally air-conditioning a building in which a computer room is on a plurality of floors, as in the conventional example, and is installed in a side room SR of a computer room DR on one floor, for example, the top floor. One air conditioner 1, two refrigerators 2 and 3 installed underground, and two cooling towers 4 and 5 installed on the roof constitute one unit.

The air conditioner 1 has two front-side circulation coils 1a and two rear-stage circulation coils 1b arranged vertically in a case, and a blower fan 1c is provided below the lower rear-stage circulation coil 1b. Are arranged. The air blown by the blower fan 1c is sent from the underfloor F to the computer room DR through the duct 1d, and is collected from the return chamber C on the ceiling through the duct 1e.

The latter-stage circulation coil 1b is always the refrigerator 2
Alternatively, a water circulation system is operably formed by the refrigerator 3. That is, the latter-stage circulation coil 1b is connected to the cold water pipes 6, 7
Are connected, and the cold water pipes 6 and 7 are branched pipes 6
A, 7A and branch pipes 6a, 7a are connected, and are connected to the refrigerator 2 and the refrigerator 3 via the branch pipes 6A, 7A and branch pipes 6a, 7a, respectively. Refrigerator 2 and refrigerator 3
Are cooling water pipes 10 and 11, cooling water pipes 12 and 1, respectively.
3 are connected, and are connected to the condenser coils 5a and 4a of the cooling towers 5 and 4 via the cooling water pipes 10 and 11 and the cooling water pipes 12 and 13. In addition, 7
B and 7b are located on the inlet side of the refrigerators 2 and 3, respectively, and pumps 12a and 1a are provided on the branch pipe 7A and the branch pipe 7a.
3a is a switching valve provided on the outlet side and the inlet side of the refrigerator 3 and provided on the cooling water pipes 12 and 13, and 11b and 13b.
Are pumps provided on the cooling water pipe 11 and the cooling water pipe 13 respectively located on the outlet side of the condensing coil 4a and the condensing coil 5a.

On the other hand, cold water pipes 8 and 9 are connected to the pre-stage side circulation coil 1a, and the cold water pipes 8 and 9 are connected to the cold water pipes 6 and 7, and the cold water pipes 6 and 7 and the branch pipe 6A. , 7A and branch pipes 6a, 7a are connected to the refrigerators 2, 3. Bypass pipes 14 and 15 are connected to the cold water pipes 8 and 9, and the bypass pipes 14 and 1 are connected.
It is connected to the cooling water pipes 12 and 13 via 5. The bypass pipes 14 and 15 are provided with a switching valve 14a,
15a is provided, and the cold water pipes 8 and 9 are provided with switching valves 8a and 9a.
And the switching valves 14a and 15a are opened, the front-side circulation coil 1a is connected to the refrigerators 2, 3
A water circulation system capable of switching between the operation according to (1) and the operation according to the condensing coil 5a provided in the cooling tower 5 is formed.

Numerals 6b and 8b are control valves provided on the cold water pipe 6 and the cold water pipe 8 respectively located on the inlet side of the front side circulation coil 1a and the rear side circulation coil 1b.
The control valves 6b and 8b are automatically opened and closed by a sensor provided under the floor F of the computer room DR.

Next, the operation of the present invention having the above structure will be described.

First, in the summer when the outside temperature is high, the bypass valves 14 and 15 are operated with the switching valves 14a and 15a closed, and cold water from the refrigerators 2 and 3 is branched into the branch pipes 6A and 7A. Through the branch pipes 6a and 7a, the cold water pipes 6 and 7 join together to circulate the downstream circulation coil 1b, and the cold water pipes 6 and 7 branch to the cold water pipes 8 and 9 to circulate the upstream circulation coil 1a. On the other hand, the cooling water from the condenser coils 5a and 4a of the cooling towers 5 and 4 circulates through the cooling water pipes 10 and 11 and the cooling water pipes 12 and 13, respectively.

On the other hand, in winter, when the outdoor temperature is low, in the middle period, etc., the switching valves 8a, 9a, 12a, 13a of the cold water pipes 8, 9 and the cooling water pipes 12, 13 are closed,
While stopping the operation of the pump 7b of the branch pipe 7a and the refrigerator 3, the switching valves 14a, 15 of the bypass pipes 14, 15 are stopped.
Operate with a open, and as shown by the thick line in Fig. 2,
The cold water from the refrigerator 2 flows through the branch pipes 6A and 7A to the cold water pipes 6 and 7, and circulates in the downstream circulation coil 1b, and the cooling water from the condenser coil 5a of the cooling tower 5 circulates through the cooling water pipes 10 and 11. While cooling tower 4
The cooling water from the condenser coil 4a of the
Through the bypass pipes 14 and 15 and further from the bypass pipes 14 and 15 to the cold water pipes 8 and 9 to circulate in the upstream circulation coil 1a.

At this time, the temperature on the inlet side of the pre-stage side circulation coil 1a is a high temperature of about 10 to 17 degrees, not a low temperature of 7 to 9 degrees in the conventional free cooling, that is,
Even if the temperature on the outlet side of the condenser coil 4a is as high as about 10 to 17 degrees, the downstream side circulation coil 1b circulates the cold water from the refrigerator 2 and keeps the temperature on the outlet side at 7 to 9 degrees. Since the insufficient cooling amount due to the supply of high-temperature cold water to the front-stage circulation coil 1a can be absorbed by the rear-stage circulation coil 1b, the temperature of the computer room DR underfloor F can be maintained at an optimum temperature of 19 degrees.

Thus, the cooling water temperature is 10 to 17 degrees instead of 7 to 9 degrees in the conventional free cooling.
In addition, the temperature of the computer room DR underfloor F is maintained at an optimum temperature even if the cooling water temperature fluctuates, so that conventional free cooling can be used at an outside air temperature of 5 ° C or less. However, in the improved type, the free cooling can be performed at the outside air temperature of about 15 ° C. or less, so that the execution period of the free cooling can be extended as compared with the conventional case and the energy saving effect can be improved.

In the above-mentioned embodiment, the front-stage side circulation coil 1a and the rear-stage side circulation coil 1b are provided one by one, but a plurality of units may be provided respectively.

[0023]

As is apparent from the above description, according to the present invention, even when the heat exchanger on the upstream side is operated by the cooling tower, the heat exchanger on the downstream side is in the operating state by the refrigerator. The insufficient cooling of the heat exchanger on the front side is absorbed by the heat exchanger on the rear side, so that free cooling can be performed even when the outside air temperature is unstable, so the execution period of the free cooling operation is extended. It is possible to improve the energy saving effect and to eliminate the operation stoppage due to the valve switching when switching the free cooling operation.Therefore, the trouble such as the rise of the room temperature under the floor of the computer etc. is eliminated and the operation reliability is improved. Can be secured.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of one unit.

FIG. 2 is an overall configuration diagram of one unit showing an operating state when the outside air temperature is low.

FIG. 3 is an overall configuration diagram of one unit of a conventional example.

FIG. 4 is an overall configuration diagram of one unit showing an operating state when the outside air temperature is low.

[Explanation of symbols]

 1 Air-conditioner 1a Front-stage side circulation coil 1b Rear-stage side circulation coil 1c Blower fan 2, 3 Refrigerator 4, 5 Cooling tower 4a, 5a Condensing coil 6, 7 Cold water pipe 8, 9 Cold water pipe 8a, 9a Switching valve 10, 11 Cooling water Pipes 12 and 13 Cooling water pipes 12a and 13a Switching valve 14 and 15 Bypass pipes 14a and 15a Switching valve

Claims (1)

[Claims] 1. An indoor unit is provided with front and rear heat exchangers, the rear heat exchanger forms a water circulation system so that the refrigerator can always operate, and the front heat exchanger is a refrigerator. A natural cooling air-conditioning device, characterized in that a water circulation system is formed by a cooling tower so that switching operation is possible.