JPH07104013B2 - Refrigerant natural circulation heat transfer device - Google Patents

Description

Description: [Industrial field of application] The present invention relates to an improvement of a refrigerant natural circulation heat transfer device that uses a refrigerant natural circulation cycle.

[Conventional technology]

Recently, there has been a demand for an air conditioner that saves energy, for example, in a room such as a computer room that has high internal heat generation and that is strictly required for temperature and humidity conditions and air cleaning. As one that meets this demand, an air conditioner that uses a refrigerant natural circulation heat transfer device that moves heat on the indoor side to the outdoor side by using low temperature outside air is in the limelight.

The refrigerant natural circulation heat transfer device is also called a thermosiphon, and is a device in which heat exchangers provided indoors and outdoors are annularly connected by a refrigerant pipe, and a low boiling point refrigerant is sealed inside.

As such a refrigerant natural circulation type heat transfer device, for example, one shown in Japanese Utility Model Laid-Open No. 61-79773 is known (shown in FIG. 6).

As shown in the figure, the refrigerant natural circulation heat transfer device 101 includes an evaporator 102 installed on the indoor side, a condenser 103 installed at a high place thereof and installed on the outdoor side, and an outlet of the evaporator 102. Gas side refrigerant pipe 104 connecting 102B and inlet 103A of condenser 103, outlet 103B of condenser 103 and inlet 102 of evaporator 102
A liquid-side refrigerant pipe 105 connecting with A is provided.

In the refrigerant natural circulation heat transfer device 101, the refrigerant is heated by the warm air inside the room in the evaporator 102, and boils and evaporates. The indoor air is cooled by the latent heat of vaporization at this time. The evaporated refrigerant becomes a gas, rises in the gas side refrigerant pipe 104, is guided to the condenser 103, and is cooled by cold outside air. The cooled refrigerant is condensed and liquefied, flows down inside the liquid side refrigerant pipe 105, and returns to the evaporator 102 again.

If the temperature of the outdoor side is lower than the temperature of the indoor side, the refrigerant circulation described above occurs due to the natural circulation force due to the pressure difference due to the phase change of the refrigerant and the difference in height of the refrigerant liquid level, and the heat on the indoor side does not exist on the outdoor side. It is released by power.

Then, the circulation amount of the refrigerant is determined from the natural circulation force, the resistance of the piping system, and the characteristics of the heat exchanger (evaporator 102, condenser 103).

[Problems to be Solved by the Invention]

In the conventional refrigerant natural circulation heat transfer device 101, the cooling capacity of the system is determined by the temperature difference between the indoor and outdoor temperatures and the refrigerant circulation amount. More specifically, this cooling capacity may become unstable when the indoor / outdoor temperature difference is small, but increases almost in proportion to the indoor / outdoor temperature difference. However, if the height difference of the liquid level of the refrigerant is small, the natural circulation force becomes small, and the cooling capacity reaches the upper limit even if the heat exchanger (evaporator 102, condenser 103) has a margin.

The effect of the difference in liquid level of the refrigerant on the cooling capacity will be described in detail.

If the height difference of the refrigerant liquid level is large, the refrigerant pressure in the evaporator 102 becomes high, and the evaporation temperature of the refrigerant becomes high. Therefore,
The difference between the evaporation temperature and the temperature of the cooled air (inside the room) around the evaporator 102 becomes small, and the cooling capacity becomes small. However, since the difference in height of the liquid surface of the refrigerant is large, the refrigerant circulation capacity is large. Therefore, the cooling capacity tends to be hard to reach the upper limit. The cooling capacity curve in this case is shown in FIG.
Shown in.

On the other hand, when the height difference of the refrigerant liquid level is small, the refrigerant pressure in the evaporator 102 becomes low, and the evaporation temperature of the refrigerant becomes low. Therefore, the difference between the evaporation temperature and the temperature of the cooled air (inside the room) around the evaporator 102 becomes large, and the cooling capacity becomes large. However, since the height difference of the liquid level of the refrigerant is small, the refrigerant circulating ability becomes small. Therefore, the cooling capacity tends to reach the upper limit easily. The cooling capacity curve in this case is shown in FIG.

Therefore, the cooling capacity for a given temperature difference is determined according to the level difference of the refrigerant liquid level.

However, in the conventional refrigerant natural circulation heat transfer device 101,
Since the cooling capacity is determined only by the indoor and outdoor temperature difference that cannot be controlled at all, if the height difference of the refrigerant liquid level is constant, the magnitude of the cooling capacity for a predetermined temperature difference is ( Only the tendency of A) or (B) is taken, and the efficiency of the cooling capacity becomes low. Therefore, if the indoor / outdoor temperature difference changes significantly, the efficiency of the cooling capacity may decrease.

The present invention has been made to solve such conventional problems, and an object thereof is to provide a refrigerant natural circulation type heat that improves the efficiency of the cooling capacity in a wide temperature range even if the temperature difference between the indoor and the outdoor greatly changes. A mobile device is provided.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides an evaporator installed on the indoor side, a condenser installed on the outdoor side and located at a high place of the evaporator, an outlet of the evaporator and an inlet of the condenser. A gas-side refrigerant pipe for connecting to the condenser and a liquid-side refrigerant pipe for connecting the outlet of the condenser and the inlet of the evaporator, and a constant distance between the evaporator, the gas-side refrigerant pipe, the condenser, and the liquid-side refrigerant pipe. In a refrigerant natural circulation heat transfer device that circulates an amount of the refrigerant and moves the heat on the indoor side to the outdoor side by the temperature difference between the temperature on the outdoor side and the temperature on the indoor side, in the middle of the liquid side refrigerant pipe, In order to increase the efficiency of the cooling capacity with respect to the temperature difference, the refrigerant liquid level displacement mechanism that changes the liquid level of the refrigerant of the evaporator according to the temperature difference is provided.

The refrigerant liquid level displacement mechanism includes a plurality of on-off valves interposed in the middle of the liquid-side refrigerant pipe, a bypass pipe connected to both sides of each on-off valve of the liquid-side refrigerant pipe, and a bypass pipe connected to each bypass pipe. It is effective to have two bypass valves mounted.

[Work]

In the present invention, when the temperature difference between the temperature on the outdoor side and the temperature on the indoor side is large, the liquid level of the refrigerant increases due to the refrigerant liquid level displacement mechanism, and the height difference of the refrigerant liquid level increases.

Therefore, the refrigerant pressure in the evaporator becomes high, and the evaporation temperature of the refrigerant becomes high. As a result, the difference between the evaporation temperature and the temperature of the cooled air (inside the room) around the evaporator is reduced,
Cooling capacity decreases. However, since the difference in height of the liquid surface of the refrigerant is large, the refrigerant circulation capacity is large. Therefore, the cooling capacity tends to be hard to reach the upper limit.

On the other hand, when the temperature difference is small, the refrigerant liquid level displacement mechanism lowers the liquid level of the refrigerant, and the height difference of the refrigerant liquid level becomes small.

Therefore, the refrigerant pressure in the evaporator is lowered, and the evaporation temperature of the refrigerant is lowered. As a result, the difference between the evaporation temperature and the temperature of the cooled air around the evaporator (inside the room) increases,
Cooling capacity increases. However, since the height difference of the liquid level of the refrigerant is small, the refrigerant circulating ability becomes small. Therefore, the cooling capacity tends to reach the upper limit easily.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show the contents of a refrigerant natural circulation heat transfer device according to a first embodiment of the present invention.

In FIG. 1, 1 is an evaporator, which is installed inside the indoor unit 2 on the indoor side. A condenser 3 is located at a high place of the evaporator 1 and is installed inside the outdoor unit 4 on the outdoor side. Indoor unit 2 and outdoor unit 4
An air blower 5 is arranged inside of the above, and is located downstream of the evaporator 1 and the condenser 3, respectively. 6 is a gas side refrigerant pipe,
The outlet 1B of the evaporator 1 and the inlet 3A of the condenser 3 are connected. 7
Is a liquid side refrigerant pipe, and the outlet 3B of the condenser 3 and the inlet of the evaporator 1
Connect with 1A. A certain amount of refrigerant circulates among the evaporator 1, the gas side refrigerant pipe 6, the condenser 3 and the liquid side refrigerant pipe 7.

A refrigerant liquid level displacement mechanism 8 is provided in the middle of the liquid side refrigerant pipe 7. The refrigerant liquid level displacement mechanism 8 changes the liquid level of the refrigerant of the evaporator 1 in accordance with the temperature difference so that the efficiency of the cooling capacity with respect to the temperature difference between the outdoor temperature and the indoor temperature is increased. Connected to the first opening / closing valve V ₂ and the second opening / closing valve V _{5 provided in} the middle of the liquid side refrigerant pipe 7 and both sides of each of the opening / closing valves V ₂ and V ₅ of the liquid side refrigerant pipe 7. First bypass pipe 9 and second bypass pipe 10, first liquid tank 11 and second liquid tank 12 installed in each bypass pipe 9, 10, and first liquid tank installed in bypass pipe 9 11
Upstream bypass valve V ₁ and downstream bypass valve V ₃ located on both sides of the second bypass tank 10 and upstream bypass valve V interposed on the second bypass pipe 10 and located on both sides of the second liquid tank 12. ₄ and a downstream bypass valve V ₆ .

Next, the operation of this embodiment will be described with reference to FIGS. 2 to 4.

FIG. 2 shows a case where the temperature difference ΔT between the outdoor temperature T ₁ and the indoor temperature T ₂ is larger than a predetermined temperature difference ΔT ₀ , and the first opening / closing valve V ₂ is closed and the upstream bypass valve is used. V ₁ and the downstream bypass valve V ₃ are open. On the other hand, the second opening / closing valve V ₅ is open, and the upstream bypass valve V ₄ and the downstream bypass valve V ₆ are closed. In this case, the liquid level of the refrigerant reaches the first liquid tank 11 by the refrigerant liquid level displacement mechanism 8 and becomes high. Therefore, the difference in height of the liquid surface of the refrigerant becomes large and is H.

Therefore, the refrigerant pressure in the evaporator 1 becomes high, and the evaporation temperature of the refrigerant becomes high. As a result, the evaporation temperature and the evaporator 1
The difference between the temperature of the air to be cooled (inside the room) and the temperature T ₂ is small (the boiling point of the refrigerant is the temperature between the outside temperature T ₁ and the inside temperature T ₂ ) and the cooling capacity Becomes smaller. However, since the height difference (H) of the liquid level of the refrigerant is large, the refrigerant circulation capacity becomes large. Therefore, the cooling capacity tends to be hard to reach the upper limit. The cooling capacity curve of the case, shown by the solid line in FIG. 4 (A) In the [Delta] T ₀ or more.

FIG. 3 shows a case where the temperature difference ΔT between the outdoor temperature T ₁ and the indoor temperature T ₂ is smaller than a predetermined temperature difference ΔT _0. The first opening / closing valve V ₂ is opened and the upstream bypass valve is used. V ₁ and the downstream bypass valve V ₃ are closed. On the other hand, the second opening / closing valve V ₅ is closed, and the upstream bypass valve V ₄ and the downstream bypass valve V ₆ are open. In this case, the liquid level of the refrigerant reaches the second liquid tank 12 by the liquid level displacing mechanism 8 and is lowered. Therefore, the difference in height of the liquid surface of the refrigerant is reduced to h.

Therefore, the refrigerant pressure in the evaporator 1 becomes low, and the evaporation temperature of the refrigerant becomes low. As a result, the evaporation temperature and the evaporator 1
The difference from the temperature T ₂ of the air to be cooled (inside the room) around is increased, and the cooling capacity is increased. However, since the difference in level of the refrigerant liquid level is small (h), the refrigerant circulation ability becomes small. Therefore, the cooling capacity tends to reach the upper limit easily.

Cooling capacity curve of this case is shown by the solid line of FIG. 4 (B) in the [Delta] T ₀ or less.

As described above, from the first liquid tank 11 to the second liquid tank
When switching to 12, the upstream bypass valve V ₁ and the second opening / closing valve V ₅ are closed manually, and the first opening / closing valve V ₂ ,
Downstream bypass valve V ₃ , upstream bypass valve V ₄
And the downstream bypass valve V ₆ is opened, and after a certain time, the first
After the liquid tank 11 is exhausted of the refrigerant liquid, the downstream bypass valve V ₃ may be closed.

On the other hand, when switching from the second liquid tank 12 to the first liquid tank 11, the first opening / closing valve V ₂ , the second opening / closing valve V ₅ ,
The upstream bypass valve V ₄ was closed, and the upstream bypass valve V ₁ , the downstream bypass valve V ₃ , and the downstream bypass valve V ₆ were opened, and after a certain time, the second liquid tank 12 ran out of refrigerant liquid. After that, the downstream bypass valve V ₆ may be closed and the second opening / closing valve V ₅ may be opened.

According to the above structure, as shown in FIG. 4, when the temperature difference ΔT changes, the cooling capacity has a high level difference of the refrigerant liquid level at ΔT ₀ or more, and the solid line (A) is selected. ,
On the other hand, when ΔT ₀ or less, the height difference of the refrigerant liquid level becomes small,
The solid line in (B) is selected. That is, in accordance with the temperature difference ΔT, the height difference of the refrigerant liquid level with respect to the temperature difference ΔT is selected.
By controlling, the efficiency of the cooling capacity with respect to the temperature difference ΔT can be increased, and therefore, the efficiency of the cooling capacity can be improved in a wide temperature range even if the temperature difference ΔT changes greatly.

In the refrigerant liquid level displacement mechanism 8 of the present embodiment, two opening / closing valves V ₂ and V ₅ are provided in the middle of the liquid side refrigerant pipe 7, and correspondingly the bypass pipes 9 and 10 are also installed. is, although the bypass valve _{V 1, V 3, V 4} , V 6 is interposed on the way, and the number of opening and closing valve 3 or more, and the number is also 3 or more bypass pipe correspondingly, A liquid tank and a bypass valve may be provided on the way corresponding to the bypass pipe.

Further, in the present embodiment, the liquid tanks 11 and 12 are provided in the bypass pipes 9 and 10, respectively, but the liquid tanks 11 and 12 may be omitted.

FIG. 5 shows a refrigerant natural circulation heat transfer device according to a second embodiment of the present invention.

As shown in the figure, the refrigerant natural circulation heat transfer device according to the second embodiment has the same basic configuration as that of the first embodiment, and the temperature of the outdoor temperature T ₁ and the indoor temperature T ₂ The control for automatically moving the heat inside the room to the outside due to the difference is performed. That is,
The temperature T ₁ of the temperature detector 21 of the outdoor side, the temperature of the indoor side T ₂
Are detected by the temperature detector 22 and
Sent to 23. In the controller 23, the temperature outside the room
The temperature difference ΔT between T ₁ and the room temperature T ₂ is calculated and compared with the set temperature ΔT ₀ . Then, the set temperature ΔT ₀ and the temperature difference Δ
According to the difference from T, as described in the first embodiment by a command from the controller 23, the first opening / closing valve V ₂ , the second opening / closing valve V ₅ , via an appropriate actuator (not shown),
Opening / closing of the upstream bypass valve V ₁ and the downstream bypass valve V ₃ of the first bypass pipe 9 and the upstream bypass valve V ₄ and the downstream bypass valve V ₆ of the second bypass pipe 10 are controlled.

According to the second embodiment, in addition to the effect of the first embodiment, the valves can be automatically controlled.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

In the refrigerant natural circulation heat transfer device according to claim 1,
When the indoor / outdoor temperature difference changes, by selecting and controlling the level difference of the refrigerant liquid level with respect to the temperature difference, it is possible to increase the efficiency of the cooling capacity with respect to the temperature difference. Even if the temperature difference largely changes, the efficiency of the cooling capacity can be improved in a wide temperature range.

In the refrigerant natural circulation heat transfer device according to claim 2,
The liquid level of the refrigerant in the evaporator can be made variable by the refrigerant liquid level displacement mechanism.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigerant natural circulation type heat transfer device according to a first embodiment of the present invention. FIG. 2 is an explanatory view of a state of use when the refrigerant natural circulation heat transfer device has a large temperature difference between the indoor and outdoor temperatures. FIG. 3 is an explanatory view of a state of use of the refrigerant natural circulation heat transfer device when the temperature difference between the indoor and outdoor sides is small. FIG. 4 is an explanatory diagram of effects of the refrigerant natural circulation heat transfer device. FIG. 5 is a block diagram of a refrigerant natural circulation type heat transfer device according to a second embodiment of the present invention. FIG. 6 is a block diagram of a conventional refrigerant natural circulation heat transfer device. FIG. 7 is an explanatory diagram of an effect of the refrigerant natural circulation type heat transfer device. [Explanation of symbols for main parts] 1 ... Evaporator 1A ... Inlet 1B ... Outlet 3 ... Condenser 3A ... Inlet 3B ... Outlet 6 ... Gas side refrigerant pipe 7 ... Liquid side refrigerant pipe 8 …… Refrigerant liquid level displacement mechanism 9 …… First bypass pipe 10 …… Second bypass pipe V ₁ …… Upstream bypass valve V ₂ …… First opening / closing valve V ₃ …… Downstream bypass valve V ₄ … … Upstream bypass valve V ₅ …… Second on-off valve V ₆ …… Downstream bypass valve.

Claims (2)

[Claims] 1. An evaporator installed inside a room, a condenser installed outside the room and located at a high place of the evaporator, and a gas-side refrigerant connecting an outlet of the evaporator and an inlet of the condenser. A pipe and a liquid-side refrigerant pipe connecting the outlet of the condenser and the inlet of the evaporator are provided, and a certain amount of refrigerant is circulated between the evaporator, the gas-side refrigerant pipe, the condenser, and the liquid-side refrigerant pipe. In the refrigerant natural circulation heat transfer device that moves the heat on the indoor side to the outdoor side due to the temperature difference between the temperature on the outdoor side and the temperature on the indoor side, in the middle of the liquid side refrigerant pipe, the cooling capacity for the temperature difference A refrigerant natural circulation heat transfer device comprising a refrigerant liquid level displacement mechanism for varying the liquid level of the refrigerant of the evaporator according to the temperature difference so as to increase efficiency. 2. The refrigerant liquid level displacement mechanism comprises a plurality of opening / closing valves interposed in the middle of the liquid side refrigerant pipe, bypass pipes connected to both sides of the opening / closing valves of the liquid side refrigerant pipe, and respective bypasses. The refrigerant natural circulation heat transfer device according to claim 1, comprising two bypass valves interposed in the pipe.