JPS61128042A - Air conditioner having cold water producing circuit - Google Patents

Abstract

PURPOSE:To enable to perform cooling by means of cold water, to permit installation of an air conditioner solely through a simple repairy work on an existing building, and to reduce a cooling operation expense, by a method where in a cold water producing circuit is additionally installed, and production of cold water is practicable with the aid of a cooling tower utilizing the open air through control of a switching valve. CONSTITUTION:2 systems of cold heat source circuits containing refrigerators 11 and 12 is provided, the cooling water side circuit of a first system comprising a cooling tower 13, a 3-way valve 31, and a pump 57 and the cooling water side circuit of a second system comprising a cooling tower 14, a 3-way valve 32, a pump 58, and switching valves 24 and 25. Control of the switch valves causes operation of a cooling tower in priority to a freezer in a cold water producing circuit to perform following 2 types of operations. (I) Free cooling. Only the cooling tower 14 is operated, and brought to a stop. In case a cooling load is low, energy-saving operation is rendered effective. (II) Series operation. The cooling tower 14, the refrigerator 11, and the cooling tower 13 are operated, and the refrigerator 12 is brought to a stop. In case a cooling load is about middle, enegy-saving operation is rendered effective.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an energy-saving air conditioner suitable for cooling equipment that generates a large amount of heat, such as a computer, or a room in which the equipment is installed.

Conventional technologyIndoors where it is difficult to cool the room with outside air to maintain internal cleanliness and relative humidity even in winter, such as rooms where computers are installed, or in buildings where outside air cooling is not possible due to location or layout, etc. However, it is necessary to operate the refrigerator to cool the room. Therefore, from the viewpoint of energy conservation, a method has been proposed in which cold water is produced in a cooling tower using outside air without operating the refrigerator in the winter, and this is used for air conditioning.

(A) JP-A No. 56-40033, ``Outside Air Chilled Water Cooling System,'' adds a chilled water coil and a chilled water switching valve to a conventional air conditioning system, and when the outside air is cold, chilled water from the cooling tower is transferred to the inside of the air conditioner. The cold water is cooled by passing it through a cold water coil. However, with this device, it is necessary to stop the water flowing to the condenser and switch to the chilled water coil, and at the same time stop the compressor and rotate only the fan. Whether cooling capacity is achieved or not depends on outside air conditions and cannot be determined until time has elapsed.Although it is a simple device, it is not easy to operate and does not provide the desired effect.

(B) There is a device shown in FIG. 3 that has been put to practical use in factories and the like. This air conditioning system includes a first cold source circuit including a refrigerator 11 and a second cold source circuit including a refrigerator 12.
It consists of two cold and heat source circuits. In summer, the switching valves 61, 62 are closed and the switching valves 63, 64, 65, 66 are opened to operate the two refrigerators simultaneously. The cooling water side circuit of the first system includes a cooling tower 51, an expansion tank 53, and a three-way valve 55.
, a pump 57, and the cooling water side circuit of the second system includes a cooling tower 52, an expansion tank 54, a three-way valve 56, and a pump 58. If an open cooling tower (see Figure 1) is used instead of the closed cooling tower 51.52, the expansion tank 53.5
4 can be omitted. Refrigerators 11 and 12 are compressors a
1 condenser b1 expansion valve C1 evaporator d. The cold water side circuit includes an air conditioner 15, an expansion tank 16, a pump 59,
60 are included.

In winter, the switching valves 61 and 62 are opened, and the switching valves 63 and 6 are closed.
4, 65, and 66 to stop the first refrigerator 11 and operate only the second refrigerator 12, or stop the refrigerator 12 as well and perform free cooling using only the cooling tower (
natural cooling).

As a result, water cooled by the cooling tower flows from the cooling water side circuit of the first system to the chilled water side circuit, and a cooling operation using outside air is performed.

However, this air conditioning system also has the following problems. First, when transitioning from summer to winter, the switching valve is operated to stop the first refrigerator, but if a hot day suddenly appears, it may be necessary to start operating the first refrigerator. Yes, it is difficult to select the switching timing. Second, in order to maintain the cooling temperature at an optimum level, operation of the cooling tower in the first system and operation of the chiller in the second system must be switched at the optimal timing, but load fluctuations on the chilled water supply side In order to perform control while constantly checking changes in air temperature and outside temperature and humidity, and taking into account delay factors such as switching time and chiller start-up time, we use a computer that can process predictive factors. I had no choice but to do it.

Problems to be Solved by the Invention The purpose of the present invention is to enable cooling using chilled water without requiring complicated control, to be able to install it in existing buildings with simple renovation work, and to reduce the cost of operating the air conditioner. An object of the present invention is to provide an air conditioner that can reduce the amount of air.

Means for Solving Problems and Their Effects The above-mentioned object of the present invention is to provide an air conditioner equipped with two or more cold source circuits, in which the chilled water side circuit of the refrigerator of the first system is connected to the second system. This is achieved by installing a chilled water production circuit connected in series with the cooling water side circuit of the refrigerator, and producing chilled water by a cooling tower using outside air by controlling a switching valve.

By connecting the chilled water circuit of the first system in series with the cooling water circuit of the second system, the water cooled in the cooling tower passes through the refrigerator before being sent to the air conditioner. , control is easier than before. For example, when the cooling load increases or the outside temperature rises while operating in a free cooling state, it is possible to operate the chiller in series with the cooling tower, allowing temperature control on the air conditioner side. is performed more smoothly than before.

The features and advantages of the invention will become more apparent from the following description with reference to the embodiment of FIGS. 1 and 2. FIG.

Embodiment FIG. 1 shows an air conditioning system according to a preferred embodiment of the present invention, which includes two cold source circuits each including a refrigerator 11, 12. The cooling water side circuit of the first system includes the cooling tower 13, the three-way valve 31, and the pump 57, and the cooling water side circuit of the second system includes the cooling tower 14, the three-way valve 32, the pump 58, and the switching valve 24. .25 is included. If a closed cooling tower (see FIG. 3) is used instead of the open cooling tower 13, 14, an expansion tank is provided in the system.

The cold water side circuit includes an air conditioner 15, an expansion tank 16, and a pump 5.
9,60. A switching valve 23 is included in each bypass circuit 17,18 provided according to the invention.
1.22 is included. Furthermore, in order to control the entire air conditioning system, temperature sensors TI, T2. T3. T4 and pressure regulators 41, 42, 43, 44 are provided.

The symbol WB indicates the outside air wet bulb temperature.

Based on this configuration, normal cooling operation is performed in the summer. That is, the switching valves 21 and 22 are closed and the bypass circuit 17 is closed.
．． Stop the flow in 18 and switch valves 23, 24, 25
When the refrigerator is opened, the two refrigerators 11 and 12 are operated simultaneously, and the cooling water side circuit of the first system and the cooling water side circuit of the second system are operated independently.

When the transition from summer to winter occurs, the switching valves 23° and 24.
25 and open the switching valve 21.22 to open the bypass circuit 17.18, thereby connecting the cold water side circuit of the first system in series with the cooling water side circuit of the second system. This completes a cold water production circuit using a cooling tower.

In this cold water production circuit, the cooling tower is operated with priority over the refrigerator, and the following two types of operation are performed.

(I) Only the cooling tower 14 is operated, and the refrigerators 11 and 12 and the cooling tower 13 are stopped. This is energy-saving operation when the cooling load is small.

(II) Series operation Cooling tower 14, refrigerator 11, and cooling tower 13 are operated, and refrigerator 12 is stopped. This is energy-saving operation when the cooling load is moderate.

Since the chilled water usage temperature is generally considered to be about 7°C for the outward route and 126°C for the return route, the temperature T3 at the outlet temperature detection end of the cooling tower 14 is equal to the temperature T3 at the outlet temperature detection end of the first refrigerator 11.
The three-way valve 32 on the side of the cooling tower 14 is controlled using the same 7°C as in 2 as the set value. The control method is carried out, for example, as shown in the flowchart shown in FIG.

The symbol is a constant that allows the cooling tower to perform outside air cooling, and is determined through experiments. If the temperature of the cold water passing through the cooling tower 14 is in the range of 7 to 12°C, the temperature is adjusted by performing throttling operation.

Effects of the Invention As explained in detail above, according to the present invention, cooling operation using chilled water can be realized without requiring a complicated and expensive control device. The device of the present invention has extremely remarkable effects, such as the fact that it can be installed in existing buildings with simple renovation work by simply installing two bypass pipes and five switching valves. There is.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an air conditioner according to the present invention;
FIG. 2 is a flowchart showing the control process, and FIG. 3 is a system diagram of a conventional chilled water production type air conditioner. 11.12... Refrigerator 13.14... Cooling tower 1
5... Air conditioner 16... Expansion tank 17.
18...Bypass circuit 21-25...Switching valve 31.32...Three-way valve 5
7-60... Pump patent applicant Shinryo Refrigeration Co., Ltd. agent Patent attorney Tadashi Ninomiya Takashi 1-1 Ward L2 Benhata 3 times

Claims (1)

[Claims] In an air conditioner equipped with one or more cold source circuits, the chilled water side circuit of the refrigerator of the first system is connected in series with the cooling water side circuit of the refrigerator of the second system. An air conditioner characterized in that it is equipped with a connected chilled water production circuit and produces chilled water using a cooling tower using outside air under the control of a switching valve. 2. Detects the cold water return temperature to the cooling tower and the outside air wet bulb temperature,
The air conditioner according to claim 1, wherein the air conditioner is controlled so that the cooling tower is operated with priority over the refrigerator.