JPH0520679B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an air conditioning system using a loop heat pipe, and particularly to an air conditioning system having a plurality of evaporators for one condenser.

[Prior art and its problems] In recent years, air conditioning cooling systems using loop heat pipes (loop thermosiphons) have begun to be studied.

The basic operation will be explained with reference to FIG. In principle, it is a loop heat pipe with an appropriate amount of refrigerant sealed inside. The system includes an evaporator (or evaporator) 1 installed as a cooler near the ceiling of a room, a steam passage 2, a condenser (or condenser) 3 having an appropriate cooling means, a liquid pipe 4, and a refrigerant. It consists of a protruding curved part 5 for circulation in one direction. The refrigerant liquid in the evaporator 1 is heated by the indoor air, evaporates, passes through the vapor ventilation path 2,
It is cooled and condensed in the condensation section 3, becomes a liquid, flows through the liquid pipe 4 by gravity, and returns to the evaporation section 1. At this time, a height difference (head) 7 is generated within the liquid pipe 4 by an amount corresponding to the pressure loss between the refrigerant vapor and the refrigerant liquid. This series of operations will cool the indoor air.

The major difference between this heat pipe type air conditioning system and commonly used cooling systems (refrigeration cycle) is that it does not use a compressor to circulate the refrigerant.
The point is that it uses gravity. Therefore, if there is a suitable cooling and heat source, no power is required, and a large energy saving effect can be expected. In such a heat pipe type air conditioning system, if the evaporator section is branched to create multiple evaporators for one condenser,
It is necessary to distribute the refrigerant liquid to send just enough refrigerant liquid to each evaporator.

In a cooling system using a compressor, in such a case, an evaporation pressure regulating valve or a refrigerant solenoid valve is used alone or in combination to sufficiently achieve the purpose. However, when used in a heat pipe type air conditioning system, the evaporation pressure regulating valve maintains the evaporation pressure constant regardless of the amount of refrigerant in the evaporator, so due to a slight difference in the initial settings, the lower setting value A phenomenon occurs in which a large amount of refrigerant liquid flows into the setting (lower evaporation pressure), and less refrigerant flows into the higher set value (higher evaporation pressure). As a result, one evaporator is short of refrigerant liquid, and the other evaporator has too much refrigerant, resulting in a reduction in cooling capacity, which is disadvantageous. Furthermore, when a solenoid valve is used, although the above-mentioned disadvantages do not occur, there are disadvantages in terms of maintenance, such as the need for periodic replacement due to limitations on lifespan due to the large number of valve opening and closing operations.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat pipe type air conditioning system that eliminates the drawbacks of the prior art described above, reliably distributes refrigerant to a plurality of evaporators, and has high long-term reliability.

[Means for Solving Problems] In order to achieve the above-mentioned object, in the present invention, as a refrigerant liquid distribution means, a protrudingly curved stepped portion is provided at the inlet of each evaporator, and a stepped portion is provided at the outlet substantially on the same horizontal plane as the evaporator tube. The structure includes a fixed throttle section for refrigerant vapor.

[Example] A specific example of the present invention will be explained with reference to FIG.

The system is composed of a plurality of evaporators 11 and 12 installed as coolers near the ceiling of the room, a steam passage 2, a condenser 3 having an arbitrary cooling means, and a liquid passage 4. A protruding curved portion 5 is provided at each inlet, and a constriction portion 6 of a fixed piping resistance (tube or orifice) is provided at each outlet.

The evaporators 11 and 12 are installed on substantially the same horizontal plane. Additionally, a suitable amount of refrigerant is sealed within the system. The heat transport effect due to evaporation and condensation of the refrigerant is the same as that explained in FIG. 2.

In this system, the refrigerant liquid is transferred to the evaporator 11,1
Simply put, the force that causes the liquid to flow into the liquid head 7 is the liquid height (head) 7, but in more detail, it is a force that is determined by the relationship between the evaporation pressure, the liquid height, and the condensation pressure.

Since the liquid height and condensation pressure are common, it can be said that the pressure within the evaporators 11 and 12 (evaporation pressure) acts as a force for distributing the refrigerant liquid to each evaporator 11 and 12. Therefore, if the evaporation pressures are equal, each evaporator 11 and 1
The liquid distribution to 2 will be evenly distributed. On the other hand, if each evaporation pressure is viewed from the viewpoint of pressure loss on the steam passage 2 side, the following relationship holds true.

Pe=Pc+ΔP ₂ +ΔP ₆ where Pe is the evaporation pressure, Pc is the condensation pressure, ΔP ₂ is the pressure loss in the steam passage 2, and ΔP ₆ is the pressure loss of the steam in the throttle section 6.

Since the condensation pressure (Pc) and pressure loss (△P ₂ ) are common, by appropriately designing the resistance coefficient of the throttle part 6, the evaporation pressure (Pe) can be made to be the same for all.
Alternatively, it is possible to make a difference depending on the amount of refrigerant liquid to be distributed.

In such a system configuration, if a liquid shortage occurs in the evaporator 11, the amount of refrigerant evaporated will decrease,
The pressure loss (ΔP ₆ ) at the constriction portion 6 is also reduced. As a result, the evaporation pressure (Pe) inside the evaporator 11 also decreases, so more refrigerant liquid flows in, and the amount of refrigerant evaporation increases again, returning to the normal state.

Next, there is a large heat load fluctuation that cannot be controlled by the pressure loss in the throttle section 6, and one evaporator,
For example, when a large amount of refrigerant liquid flows into the evaporator 11, the constriction part 6 is on the same horizontal plane as the evaporation pipe of the evaporator, so the constriction part 6 is blocked by the refrigerant liquid that has flowed into the evaporator 11. Evaporation pressure increases. As a result, the refrigerant liquid no longer flows into the evaporator 11, but instead flows into the evaporator 12 where the refrigerant liquid is insufficient.

[Effect of the invention] In the air conditioning system having the above structure,
When an imbalance occurs in the distribution of refrigerant and a shortage of refrigerant occurs in one evaporator, the evaporation pressure decreases due to changes in pressure loss at the throttle section, so more refrigerant flows in and functions to compensate for the shortage. do. As a result, the refrigerant liquid in each evaporator is automatically distributed without ever running out. In addition, when a large amount of refrigerant liquid flows into the evaporator due to large heat load fluctuations that cannot be controlled due to pressure loss in the throttle section, automatic adjustment can be made to prevent further refrigerant liquid from flowing into the evaporator. can.

As described above, in the present invention, the refrigerant liquid is reliably distributed to each evaporator with a simple mechanism, and there is no need to worry about the life of the evaporator since there are no moving parts. Naturally, this method also has the advantage of being significantly cheaper than a method using a control valve.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of an air conditioning system according to the present invention, and FIG. 2 is an explanatory diagram of the basic principle of a heat pipe type air conditioning system. 1, 11 and 12...evaporation section (evaporator), 2...
...Steam passage, 3... Condensation section (condenser), 4... Liquid passage, 5... Step section, 6... Throttle section, 7... Liquid height (head).

Claims (1)

[Claims] 1. In a loop type thermosiphon, a pipe or container is formed into a loop-shaped closed circuit, an appropriate amount of refrigerant is sealed inside, and a temperature difference is applied to cause the refrigerant to boil and condense to transport heat. arranged as a condenser with optional cooling means,
The evaporator section is branched in a closed circuit and arranged as a plurality of coolers, and each evaporator section has a protrudingly curved stepped section on the inlet side, and an evaporation pipe of the evaporator section on the outlet side. A heat pipe type air conditioning system characterized in that a fixed throttle section for refrigerant vapor is provided on substantially the same horizontal plane as the heat pipe type air conditioning system.