Refrigerant discharge method

Abstract

This invention provides a method for reducing the force of refrigerant gas release during a fire. [Solution] If the fire detector detects a fire, the signal from the fire detector will switch the three-way valve to the discharge position. When the three-way valve is switched to the discharge position, the refrigerant compressed by the compressor is released through the discharge piping into a water tank outside the room. Being released into water reduces the force of the release, preventing the refrigerant from spreading over long distances.

Description

Technical Field

[0001] The present invention relates to a method for discharging refrigerant from an air conditioning system interlocked with a fire detector.

Background Art

[0002] Refrigerants include natural refrigerants such as propane and propylene mixed, and alternative fluorocarbons (non-natural refrigerants) such as HFC (hydrofluorocarbon). Refrigerants containing fluorine such as HFC have a high ozone depletion potential (ODP) and global warming potential (GWP), so their release to the outside air is strictly regulated.

[0003] In Patent Document 1, as a method for dealing with leakage of natural refrigerant, a detector and a suction port of a suction pipe are arranged near a joint portion with a refrigerant pipe of an indoor unit. If the detector detects refrigerant leakage, the ventilation fan is driven to suck air containing refrigerant from the suction port of the suction pipe and discharge it to the outside, thereby maintaining the concentration of refrigerant gas in the atmosphere around the indoor unit below the explosion limit while continuing the operation of the outdoor unit and the indoor unit.

[0004] Patent Document 2 discloses an air conditioner using a flammable refrigerant that detects leakage of the flammable refrigerant during operation. This air conditioner has a casing formed with a suction port and a blowout port on the top surface, and a heat exchanger and a blower housed in the casing. During operation, while flowing the flammable refrigerant through the heat exchanger, the blower is rotated to take in air from the suction port into the casing, perform heat exchange between the taken-in air and the flammable refrigerant in the heat exchanger, and blow out the air after heat exchange from the blowout port to the outside of the casing. In particular, the heat exchanger and the blower are arranged in the order of the heat exchanger and the blower with respect to the air flow in the casing, and the first refrigerant sensor is arranged on the downstream side of the heat exchanger and on the upstream side of the blower. Therefore, in the detection of the flammable refrigerant by the first refrigerant sensor, it is made difficult to be affected by the atmosphere in which the flammable refrigerant outside the casing has diffused.

[0005] Patent Document 3 proposes an indoor unit that allows the user to arbitrarily disable a refrigerant leak alarm. This indoor unit comprises a casing, a heat exchanger through which a flammable refrigerant flows, a fan, a detection sensor for detecting a leak of the flammable refrigerant, an alarm device for issuing an alarm when a leak of the flammable refrigerant occurs, a control device for controlling the operation of the fan and the alarm device, and an operating device for inputting stop commands for the fan and the alarm device to the control device based on manual operation. The disclosure states that when a leak of the flammable refrigerant is detected by the detection sensor, the control device starts the fan if it is stopped, activates the alarm device, ignores the stop command for the fan issued by the operating device, and allows the stop command for the alarm device issued by the operating device.

[0006] patent literature Document 4 discloses a mixed refrigerant comprising propane, propylene, and isobutane as an unavoidable component as a natural refrigerant, characterized in that the mixing ratio of propane and propylene is 50:50 and the water content is 5 ppm by weight or less. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2018-159475 [Patent Document 2] Japanese Patent Publication No. 2015-158282 [Patent Document 3] Japanese Patent Publication No. 2015-094515 [Patent Document 4] Japanese Patent Publication No. 2015-086351 [Overview of the project] [Problems that the invention aims to solve]

[0008] Patent Document 1 assumes the use of natural refrigerants and describes how to discharge leaked refrigerant outside the room. However, since refrigerants are flammable, the method of discharge during a fire must not ignite or spread the fire, and this issue is not resolved in Patent Document 1. In other words, if the refrigerant gas is released directly into the outside air by an exhaust fan, the force of the release could reach several meters away, and if there is an open flame nearby, it could ignite.

[0009] Patent documents 2 and 3 assume the use of fluorine-containing refrigerants (alternative fluorocarbons) as refrigerants. Legally, alternative fluorocarbons cannot be released into the atmosphere under laws such as the Ozone Layer Protection Act and the Fluorocarbon Emissions Control Act. Therefore, in the event of a leak, the refrigerant is diffused into the room to dilute its concentration. However, using the same measures in the event of a fire as in the event of a leak would be dangerous due to the flammability of the refrigerant.

[0010] Patent document 4 describes a mixed natural refrigerant of propane and propylene, but it does not describe what to do in the event of leakage or fire. [Means for solving the problem]

[0011] To solve the above problems, the method for discharging refrigerant from an air conditioning system according to the present invention involves branching a refrigerant discharge pipe from a high-pressure pipe that sends a partially gaseous refrigerant, which is at high temperature and pressure from a compressor, to the condenser of an indoor or outdoor unit. A valve is provided at the branching point of this refrigerant discharge pipe to discharge the refrigerant to the outside via the refrigerant discharge pipe in accordance with instructions from a control device that receives a fire signal. Furthermore, the tip of the refrigerant discharge pipe faces a water tank located away from the building (for example, 2m or more) and discharges the refrigerant gas into the water.

[0012] The aforementioned refrigerant can be a natural refrigerant, which is a mixture of propane and propylene. Furthermore, the present invention can also be applied to highly toxic refrigerants such as ammonia and fluorocarbon gases, provided that the structure prevents the refrigerant gas from leaking out of the water tank. [Effects of the Invention]

[0013] According to the present invention, in case of a fire, a flammable natural refrigerant can be quickly released outdoors, preventing secondary disasters. In particular, if the flammable natural refrigerant is released directly outdoors, there is a risk that the refrigerant gas will scatter to an unexpected position and spread due to the momentum of the release. However, by releasing the refrigerant gas into water, the momentum of the release can be eliminated and the scattering of the refrigerant gas can be prevented.

Brief Description of the Drawings

[0014] [Figure 1] A diagram showing an overview of the air conditioning system during cooling operation [Figure 2] A diagram showing an overview of the air conditioning system during heating operation [Figure 3] A diagram showing an overview of the air conditioning system (cooling operation) to which the refrigerant discharge method according to the present invention is applied [Figure 4] (A) and (B) are diagrams showing alternative embodiments of the water tank

Embodiments for Carrying Out the Invention

[0015] The air conditioning system to which the refrigerant discharge method according to the present invention is applied is composed of an indoor unit 1 and an outdoor unit 2. A heat exchanger 3 is incorporated in the indoor unit 1, and a set of heat exchangers 4 is incorporated in the outdoor unit 2.

[0016] The heat exchanger 3 in the indoor unit 1 functions as an evaporator during cooling operation and as a condenser during heating operation. The heat exchanger 4 in the outdoor unit 2 functions as a condenser during cooling operation and as an evaporator during heating operation.

[0017] A compressor 5 and a switching valve 6 for switching between cooling operation and heating operation are provided in the outdoor unit 2. The refrigerant that is partially gasified at high temperature and high pressure sent out from the compressor 5 is sent out through a delivery pipe (high-pressure pipe) 7. A discharge pipe 9 branches from the middle of this delivery pipe (high-pressure pipe) 7 via a three-way valve 8, and the tip of the discharge pipe 9 is connected to a water tank 10 arranged outdoors.

[0018] When the switching valve 6 is switched to the cooling operation, as shown in FIG. 1, part of the refrigerant compressed by the compressor 5 at high temperature and high pressure and which has become partially liquid enters the heat exchanger (condenser) 4 of the outdoor unit 2 via the delivery pipe 7, the switching valve 6, and the pipe 11. Here, the refrigerant becomes a medium-temperature and medium-high pressure liquid and evaporates in the heat exchanger (evaporator) 3 of the indoor unit 1 via the pipe 12 to supply cold air into the room. The refrigerant that has exited the heat exchanger (evaporator) 3 becomes a low-temperature and low-pressure gas and is returned from the pipe 13 via the switching valve 6 and the pipe 14 to the compressor 5.

[0019] Here, the pipe 11 includes an expansion valve (capillary tube) 15, and the pipe 14 includes an accumulator 16.

[0020] When the switching valve 6 is switched to the heating operation, as shown in FIG. 2, part of the refrigerant compressed by the compressor 5 at high temperature and high pressure and which has become partially liquid enters the heat exchanger (condenser) 3 of the indoor unit 1 via the delivery pipe 7, the switching valve 6, and the pipe 13. Here, the refrigerant becomes a medium-temperature and medium-high pressure liquid, and the condensation heat (warm air) at that time is supplied into the room. The refrigerant that has exited the heat exchanger (condenser) 3 becomes a medium-temperature and medium-high pressure liquid and enters the heat exchanger (evaporator) 4 of the outdoor unit 2 via the pipe 12 to evaporate and release cold air to the outside. The refrigerant that has exited the heat exchanger (evaporator) 4 becomes a low-temperature and low-pressure gas and is returned to the compressor 5 via the pipe 11, the switching valve 6, and the pipe 14.

[0021] When the fire detector detects a fire, as shown in FIG. 3, the three-way valve 8 is switched to the discharge side by the signal from the fire detector. Note that although the three-way valve 8 is shown in the drawing, it is not limited to this, and an on-off valve or the like may be combined.

[0022] When the three-way valve 8 is switched to the discharge side, the refrigerant compressed by the compressor � is discharged into the outdoor water tank 10 via the discharge pipe 9. By discharging into the water, the momentum of the discharge is reduced and the refrigerant does not diffuse far.

[0023] FIG. 4 shows Aquarium Another embodiment of 10, and in this embodiment AquariumA partition wall 10a that can slide along the inner wall of the water tank 10 is placed inside the tank 10. As shown in (A), when the three-way valve 8 switches from its normal state to the discharge side due to a signal from the fire detector, as shown in (B), the refrigerant gas is released into the water tank 10, and the partition wall 10a moves upward in proportion to the amount of refrigerant gas released, absorbing the released amount.

[0024] By arranging the partition wall 10a in this way, even if the refrigerant is ammonia or a fluorine-based refrigerant, it can be released outside without being diluted and diffused into the room. This is particularly effective for ammonia, as it dissolves well in water. [Explanation of Symbols]

[0025] 1...Indoor unit, 2...Outdoor unit, 3, 4...Heat exchanger, 5...Compressor, 6...Switching valve, 7...Discharge piping (high-pressure piping), 8...Three-way valve, 9...Discharge piping, 10...Water tank, 10a...Partition wall, 11, 12, 13, 14...Piping, 15...Expansion valve (capillary tube), 16...Accumulator.

Claims

[Claim 1] A method for discharging refrigerant from an air conditioning system, wherein a partially gaseous refrigerant at high temperature and pressure from a compressor is sent to a condenser of an indoor or outdoor unit via high-pressure piping, the refrigerant being a natural refrigerant mixed with propane and propylene or a refrigerant containing fluorocarbons, the refrigerant discharge pipe branching off from the high-pressure piping to the outside, a valve provided at the branching point that directs the refrigerant to the refrigerant discharge pipe upon instruction from a control device that receives a fire signal, and the tip of the refrigerant discharge pipe facing a water tank located away from the building, thereby releasing the refrigerant gas into the water.

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