JP2724028B2 - Refrigerant natural circulation cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention connects a condenser as a heat source and an evaporator as a use side through a refrigerant liquid pipe and a refrigerant vapor pipe, and connects the condenser to the condenser. The refrigerant is configured to circulate and flow in a sealed state between the evaporator and the refrigerant liquid pipe and the refrigerant vapor pipe, and a refrigerant that changes phase from liquid to vapor with heat exchange in the evaporator is used as the refrigerant. In addition, a head difference is provided between the condenser and the evaporator, which is sufficient to transfer the refrigerant that has changed into a liquid to the evaporator, and the inner and outer chambers of the diaphragm are provided at the inlet of the refrigerant liquid pipe to the evaporator. And a flow control valve that operates in response to the pressure difference between the heat sensitive cylinder and the inner chamber is provided at the outlet of the refrigerant vapor pipe from the evaporator to detect the refrigerant temperature by heat transfer. And the pressure equalizing refrigerant in the outer chamber. It relates refrigerant natural circulation type cooling system configured to flow into.

<Conventional technology> In the above-described system, as a configuration for converting the refrigerant temperature in the temperature-sensitive cylinder into pressure and transmitting the pressure to the inner chamber of the diaphragm,
In the case of a so-called gas charge method in which a gas with a small degree of saturation is filled in the thermosensitive cylinder, the temperature of the equalizing refrigerant flowing into the outer chamber side of the diaphragm is lower than the refrigerant temperature sensed by the thermosensitive cylinder. For this reason, the working fluid evaporates from the temperature sensing portion and accumulates on the diaphragm side and cannot be used. Therefore, in general, a fluorocarbon solution (for example, R-2
The so-called liquid charging method is adopted, in which 2) is filled and the diaphragm is operated by the movement of the free liquid level.

<Problem to be Solved by the Invention> However, as shown in the graph of the characteristic curve in FIG. 4 (b), the liquid charge method has a large change in pressure with respect to a change in temperature, has a high sensitivity, and has a high flow rate control. Since the opening of the valve changes abruptly, hunting is apt to occur and liquid back is unexpectedly generated, so that the cooling operation is disabled. In the graph, b
Shows a saturation curve of the Freon liquid R-22, and B shows a degree of superheat of 5 ° C. at a temperature of 0 ° C. (3.3 kgf as a secondary pressure).
/ cm ² ).

In addition, when an evaporator is provided on each of a plurality of floors, there is a difference in pressure applied to the evaporator inlet due to the weight of the refrigerant liquid in the refrigerant liquid pipe. If you try to avoid it, for example,
Adjusting the pipe diameter of the refrigerant pipe in the evaporator to change the pipe resistance so that the pressure difference on the lower floor is larger than that on the upper floor, or restricting the flow control valve in a steady state. The pressure difference to be set between the inlet and the outlet of each evaporator must be adjusted for each evaporator, for example, by adjusting the degree thereof.

The present invention has been made in view of such circumstances, and suppresses hunting of a flow control valve so that liquid back can be satisfactorily avoided. The purpose of the present invention is to make it possible to easily adjust the adjustment according to the system.

<Means for Solving the Problems> In order to achieve the above-described object, the present invention provides a refrigerant natural circulation type cooling system according to the first aspect of the present invention, which comprises: The inside is filled with an activated carbon material having a gas adsorption capacity and a gas adsorption amount relatively changing according to a temperature change, and is filled with a gas which does not condense at an ambient temperature.

According to a second aspect of the present invention, in the refrigerant natural circulation cooling system according to the first aspect of the present invention, a plurality of evaporators on the use side have different heights from each other. It is provided and configured.

<Operation> According to the configuration of the refrigerant natural circulation cooling system according to the invention of claim (1), the refrigerant temperature at the outlet from the evaporator is transmitted from the temperature-sensitive cylinder to the gas via the activated carbon material. Therefore, sensitivity can be suppressed.

In addition, by changing the filling rate of the activated carbon material, the degree of pressure change with respect to the change in the sensed temperature of the temperature sensing tube can be changed, and the sensitivity can be adjusted as the degree of superheat or the evaporation temperature of the refrigerant is adjusted. . In addition, linear characteristics can be exhibited.

Further, according to the configuration of the refrigerant natural circulation type cooling system according to the invention of claim (2), the filling rate of the activated carbon material to be charged into the temperature-sensitive cylinder is adjusted, so that each of the plurality of evaporators is controlled. Sensitivity can be adjusted.

<Example> Next, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall system configuration diagram showing an embodiment of a refrigerant natural circulation type cooling system configured in a one-block system, where 1 shows a condenser which is a heat source installed on the roof of a building or the like. Cold water or ice slurry from a heat source is supplied to the condenser 1.

An individual air conditioner 4 including a blower fan 2 and an evaporator 3 serving as a user is provided in each room on each floor of the building.

A refrigerant liquid pipe in which the condenser 1 and the evaporator 3 are each provided with a liquid receiver 5 and a gas-liquid separator 6 as a gas-liquid separator.
7a and a refrigerant vapor pipe 7b, which are in communication with each other, and
.., The refrigerant liquid pipe 7a and the refrigerant vapor pipe 7b, the phase changes from liquid to vapor with heat exchange in the evaporator 3, and from vapor to liquid by condensation in the condenser 1. A phase-change refrigerant is sealed in a sealed state.

The liquid receiver 5 is installed at a higher position than each of the evaporators 3. The refrigerant phase-changed from vapor to liquid by condensation in the condenser 1 is supplied to the evaporator 3 while flowing down. There is provided a head difference sufficient for the refrigerant phase-changed from liquid to vapor to rise and return to the condenser 1 in accordance with the heat exchange of the refrigerant. It is configured to naturally circulate and flow between 1 and the evaporator 3.

As the refrigerant, Freon gas R-22 is used. This Freon gas R-22 contains hydrogen and chlorine and decomposes into the troposphere, and thus has the advantage of not destroying the ozone layer.

At the inlets of the refrigerant liquid pipes 7a to the evaporators 3,..., There are provided a flow control valve 8 for adjusting the refrigerant liquid inflow amount and an electromagnetic opening / closing valve 9 for preventing the refrigerant liquid inflow.

A temperature sensing tube 10 for sensing the temperature of the coolant vapor is provided at the outlet of each of the evaporators 3... Of the refrigerant steam pipe 7b, and the temperature sensing tube 10 and the flow control valve 8 are connected.

As shown in the vertical cross-sectional view of FIG. 2, the flow control valve 8 is provided with a valve body 13 for adjusting the opening at an intermediate position of a communication passage 12 formed in a valve box 11. A compression coil spring 14 is provided and urged to move the valve body 13 to the closing side.

An inner chamber 16 and an outer chamber 17 partitioned by a diaphragm 15 are formed at an upper portion of the valve box 11, and the diaphragm 15 and the valve body are formed.
13 are interlockingly connected via a valve stem 18.

The inner chamber 16 of the diaphragm 15 and the internal space of the temperature-sensitive cylinder 10 are connected in communication, while the outer chamber 17 of the diaphragm 15 and the portion of the communication passage 12 downstream of the valve 13 The communication is connected through 19.

The temperature-sensitive cylinder 10 is filled with an activated carbon material 20 having a gas adsorbing ability, and is filled with an inert gas such as nitrogen gas. As the temperature of the refrigerant is sensed through the refrigerant vapor pipe 7b, the temperature is sensed. The gas adsorption amount changes according to the temperature, and the pressure applied to the inner chamber 16 of the diaphragm 15 changes accordingly, and the value obtained by multiplying the pressure of the inner chamber 16 by the effective area of the diaphragm 15 and the outer chamber 17 The diaphragm 15 is displaced so that the value obtained by multiplying the pressure of the diaphragm 15 by the effective area of the diaphragm 15 and the value obtained by adding the compression load by the compression coil spring 14 are mutually balanced, thereby automatically opening the valve body 13. It is configured to be adjustable.

In the figure, reference numeral 21 denotes a seal cap, and reference numeral 22 denotes a spindle for adjusting the urging force of the compression coil spring 14.

The electromagnetic on-off valve 9 is closed when the cooling operation is stopped, and is opened in conjunction with the driving of the blower fan 2 at the start of the cooling operation. In addition, the solenoid on-off valve 9
Is automatically controlled to open and close by comparison between a room temperature sensor that measures the temperature of the return air of the evaporator 3 and the set room temperature in the cooling operation state, thereby maintaining the room temperature within the set range. Be composed.

The gas sealed in the temperature-sensitive cylinder 10 is not limited to nitrogen gas, but may be, for example, an inert gas such as neon gas or argon gas, or a gas whose condensation liquefaction temperature is lower than the operating temperature. Any gas that does not need to be used.

Next, the ratio of the activated carbon material 20 to be filled therein, that is, two types of temperature-sensitive cylinders having different activated carbon filling rates,
A description will be given of a performance comparison test of each of the air characteristics and the time constant characteristics performed using each of the temperature-sensitive cylinders of the comparative example product which is not filled with any activated carbon material.

 First, a test body will be described.

First Embodiment Product A1 A thermosensitive cylinder having an outer diameter of 12.7 mm and a length of 80 mm is filled with activated carbon having a benzene adsorption power of 43 to 46% so as to occupy 85 to 95% of the internal volume, and nitrogen gas is supplied. Was enclosed.

Second Embodiment Product A2 A thermosensitive cylinder having an outer diameter of 9.53 mm and a length of 80 mm is filled with activated carbon having a benzene adsorption power of 43 to 46% so as to occupy 75 to 85% of the internal volume, and nitrogen gas. Was enclosed.

Comparative Example Product B Fluorocarbon liquid R-22 in a thermosensitive cylinder with an outer diameter of 16 mm and a length of 76 mm
Was put.

[Air characteristics] As a test method, an apparatus as shown in the schematic configuration diagram of Fig. 3 was used.

That is, the pressure reducing valve 21 and the first
A supply pipe 23 having an electromagnetic on-off valve 22 interposed therebetween is connected, while a cylinder 24 having a capacity of 1 and a second electromagnetic on-off valve 25 are provided on the outlet side.
And an exhaust pipe 27 having an orifice 26 at the end is connected.

A first pressure gauge 28 is provided between the pressure reducing valve 21 of the air supply pipe 23 and the first electromagnetic on-off valve 22, while a first pressure gauge 28 is provided between the cylinder 24 of the exhaust pipe 27 and the second electromagnetic on-off valve 25. Two pressure gauges 29 are provided.

 Then, the temperature sensing tube 10 is housed in the thermostat 30.

Under such conditions, the pressure measured by the first pressure gauge 28 is adjusted by the pressure reducing valve 21 so as to be 14 kgf / cm ² , and the first and second solenoid valves 22 and 25 are opened, and the orifice In the state of being released from 26, while changing the temperature in the thermostat 30 by 1 ° C., and maintaining each temperature for 10 minutes, the secondary pressure is measured by the second pressure gauge 29, and the temperature of the thermostat 30 is measured. That is, when the temperature of the temperature-sensitive cylinder 10 is plotted on the horizontal axis and the secondary pressure is plotted on the vertical axis, the characteristic curves A1, A2 shown in the graph of FIG. The characteristic curve B shown in the graph of (b) was obtained.

Further, for each of the products A1 and A2 of the first and second examples and the comparative example, the temperature of the thermostatic chamber 30 was changed to 0 ° C. and 10 ° C., and the difference Δp of the secondary pressure was obtained. The results shown in the table were obtained.

[Time constant characteristics] Using the test apparatus described above, products A of the first and second embodiments were used.
The secondary pressure measured from the time when the temperature chamber 30 was changed by changing the temperature chamber 30 to -10 ° C. and + 5 ° C. The secondary pressure is measured by the second pressure gauge 29 every one second until the pressure is stabilized, and as shown in the explanatory diagram of the test method of the time constant characteristic in FIG. The time (Tu) until the change to the rising side up to 63.2% of the time was calculated as the time constant when rising, and the time until the change to the falling side (Td) was calculated as the time constant during the fall. The results shown in the table were obtained.

From these results, it is found that both of the products A1 and A2 of the first and second embodiments have a smaller pressure change with respect to the change of the sensed temperature than the product B of the comparative example, and furthermore, the change of the sensed temperature on the rising side and the change on the falling side. Response time is slow,
It is clear that the sensitivity can be suppressed.

Further, the sensitivity can be adjusted by adjusting the filling rate of the activated carbon material 20 to be charged into the temperature-sensitive tank 10, and there is an advantage that a flow control valve having a desired sensitivity can be appropriately formed. Therefore, in the case of constructing a natural circulation type cooling system by providing a large number of evaporators 3 in the vertical direction, for example, in the uppermost evaporator 3, 0.5 kgf / c is set between its inlet and outlet.
While the pressure difference of m ² is provided, the lowermost evaporator 3 can easily cope with the case where a pressure difference of 3.0 kgf / cm ² must be provided.

The present invention can be applied not only to the above-described one-block type refrigerant natural circulation type cooling system but also to a three-block type refrigerant natural circulation type cooling system.

That is, as shown in FIG. 6, the evaporators 3 for each of the two floors are divided into three blocks, each of which is a block, and the refrigerant liquid pipe 7b from the receiver 5 is provided with a branch refrigerant liquid corresponding to each block. Are connected to the evaporators 3 through pipes 7A, 7B and 7C, respectively.

Each of the branch refrigerant liquid pipes 7A, 7B, 7C has a solenoid on-off valve 31A,
31B, 31C are interposed, and the refrigerant flow rate in each of the branch refrigerant liquid pipes 7A, 7B, 7C is higher than the uppermost evaporator 3 connected to the branch refrigerant liquid pipes 7A, 7B, 7C. It is configured such that it can be adjusted so as to have a predetermined head difference sufficient to supply the liquid downward.

In the above embodiment, a large number of evaporators 3 are provided. However, in the present invention, for example, one evaporator 3 is provided, and cool air obtained by the evaporator 3 is distributed and supplied to each room and the like via a duct. The present invention can be applied to such a case.

<Effect of the Invention> According to the refrigerant natural circulation type cooling system according to the first aspect of the present invention, the sensitivity of the operation of the diaphragm in accordance with the change in the temperature sensed by the temperature sensing cylinder can be suppressed. Abrupt changes in the opening of the control valve can be avoided,
Hunting can be suppressed to prevent unexpected occurrence of liquid back, and cooling operation can be continued satisfactorily.

Further, the sensitivity adjustment accompanying the adjustment of the degree of superheat and the evaporation temperature of the refrigerant according to the system can be easily performed only by changing the filling rate of the activated carbon material.

Further, according to the refrigerant natural circulation type cooling system according to the invention of claim (2), the adjustment of the pressure difference between the inlet and the outlet of each of the plurality of evaporators can be performed only by changing the filling rate of the activated carbon material. It is possible to easily and inexpensively construct a refrigerant natural circulation type cooling system using the same specifications as the evaporator and the flow control valve.

[Brief description of the drawings]

The drawings show an embodiment of a refrigerant natural circulation type cooling system according to the present invention. FIG. 1 is an overall system configuration diagram of a one-block type embodiment, FIG. 2 is a longitudinal sectional view of a flow control valve, and FIG. FIG. 3 is a schematic configuration diagram of a test device for air characteristics and time constant characteristics, FIG. 4 is a characteristic curve diagram showing the relationship between the temperature-sensitive cylinder temperature and the secondary pressure, and FIG. FIG. 6 is an explanatory diagram of a test method, and FIG. 6 is an overall system configuration diagram of an embodiment of a three-block system. 1 Condenser 3 Evaporator 7a Refrigerant liquid piping 7b Refrigerant vapor piping 8 Flow control valve 10 Thermosensitive cylinder 15 Diaphragm 16 Inner chamber 17 Outer chamber 20 … Activated carbon material

Continued on the front page (72) Inventor Yoshitaka Sasaki 4-1-1-13 Honcho, Chuo-ku, Osaka-shi, Osaka Inside the Osaka Main Store of Takenaka Corporation (72) Inventor Shuji Sugiura 4-1-1, Honcho, Chuo-ku, Osaka-shi, Osaka No. 13 Takenaka Corporation, Osaka Main Store (72) Inventor Kensuke Tokunaga 4-1-1, Honcho, Chuo-ku, Osaka City, Osaka Prefecture No. 13 Takenaka Corporation, Osaka Main Store (72) Inventor Shoji Aida Koyata, Iruma City, Saitama Prefecture 1-12-243 Inside the Toyooka Plant of Sagimiya Manufacturing Co., Ltd.

Claims (2)

(57) [Claims] 1. A condenser as a heat source and an evaporator as a use side are connected through a refrigerant liquid pipe and a refrigerant vapor pipe, and the condenser, the evaporator, the refrigerant liquid pipe and the refrigerant vapor are connected. The refrigerant is configured to circulate and flow in a sealed state over the pipe, and, as the refrigerant, a refrigerant that changes phase from liquid to vapor with heat exchange in the evaporator is used, and the condenser and the condenser are used. A head difference is provided between the evaporator and the evaporator so that the refrigerant that has changed into a liquid phase is transferred to the evaporator. A flow control valve that operates in response to a pressure difference is provided, and a temperature-sensitive cylinder that senses a refrigerant temperature by heat transfer is provided at an outlet of the refrigerant vapor pipe from the evaporator, and the temperature-sensitive cylinder and the temperature-sensitive cylinder are connected to each other. To communicate with the inner room A refrigerant natural circulation type cooling system configured to flow the equalizing refrigerant into the outer chamber, wherein the temperature-sensitive cylinder has a gas adsorption capacity and a gas adsorption amount changes proportionally according to a temperature change. A refrigerant natural circulation type cooling system characterized by being filled with an activated carbon material and filled with a gas that does not condense at ambient temperature. 2. The natural refrigerant cooling system according to claim 1, wherein a plurality of evaporators on the use side are provided at different heights from each other.