JP2000006801A - Air conditioner for railway rolling stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent intrusion of hydrocarbon into a passenger room even when it leaks, to dilute a leaked coolant by outside air so that it does not explode and to minimize leaked gas quantity on an air conditioner using hydrocarbon as a coolant. SOLUTION: This air conditioner is constituted of a first stage refrigerating cycle A with hydrocarbon as a coolant and a second stage refrigerating cycle B with water as a coolant, and a passenger room 20 is cooled by the second stage refrigerating cycle B. An indoor cabin is isolated from the cabin outside by a partition wall and is frame-structured so that an intermediate heat exchanger room in which an intermediate heat exchanger to exchange heat is arranged is ventilated by air of an outdoor air blower between the first stage and second stage refrigerating cycles. Additionally, a compressor is stopped by detecting gas leakage or detecting temperature rise, and gas leaking quantity is minimized by closing a solenoid valve on the high pressure side.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a railway vehicle, and more particularly to an air conditioner suitable for using hydrocarbons as a refrigerant.

2. Description of the Related Art In a conventional refrigeration cycle of a railway vehicle air conditioner, since refrigerant having a high global warming potential is used as a refrigerant, there is a possibility that the environment may be destroyed by air bleeding work or leakage when the refrigerant is charged. . For example, it is described in the document “Frozen”, Vol. 67, No. 775, pp. 57 to 60. Therefore, it is conceivable to apply a refrigeration cycle using natural refrigerants such as ammonia and hydrocarbons, which have almost zero global warming potential other than chlorofluorocarbons.However, ammonia and hydrocarbons are flammable substances, It is necessary to avoid the danger of explosion, and there is a strong demand for highly public vehicles such as railway vehicles.

In the air conditioner for a railway vehicle using the flammable refrigerant, even if the flammable refrigerant leaks, the leaked gas is prevented from being filled in the passenger compartment. In addition, the leaked gas has an explosive concentration (2.3 with propane).
９9.5 vol%) with the outside air.
Furthermore, it is necessary to take measures such as minimizing the amount of gas leaking from the refrigeration cycle. An object of the present invention is to provide a railway vehicle air conditioner that can prevent entry into a passenger compartment even if a refrigerant leaks.

Means for Solving the Problems An intermediate heat exchanger corresponding to an evaporator of the first refrigeration cycle is provided with a first refrigeration cycle using hydrocarbon as a refrigerant and a second refrigeration cycle using water as a refrigerant. Then, the water in the second refrigeration cycle is cooled, and the cooled water is sent to the indoor heat exchanger by a pump to cool the circulating air in the cabin. The intermediate heat exchanger is provided in the intermediate heat exchanger room between the outdoor unit room and the indoor unit room, and is isolated from the indoor unit room so that even if hydrocarbons leak, they do not enter the passenger room side. One refrigeration cycle is configured in an intermediate heat exchanger room and an outdoor unit room. The intermediate heat exchanger room is provided with a plurality of holes in the frame so that the wind of the outdoor blower passes outside. When a gas leak detector is installed in the intermediate heat exchanger room and a gas leak is detected or a thermal relay attached to the surface of the compressor is activated, the compressor is stopped and an electromagnetic valve installed on the high pressure side of the refrigeration cycle. And shut off the high pressure side and low pressure side.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the embodiments shown in FIGS. Here, FIG. 1 is a system diagram of a refrigeration cycle, FIG. 2 is a configuration diagram of an air conditioner mounted on a roof, FIG. 3 is a main cross-sectional view of an intermediate heat exchanger room viewed from an indoor unit room side, and FIG. FIG. 5 is a control flowchart. In FIG. 1, reference numeral 1 denotes a compressor, which compresses a low-pressure gas refrigerant into a high-temperature, high-pressure gas refrigerant. Reference numeral 2 denotes an outdoor heat exchanger, which cools and condenses the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 with the outside air blown by the outdoor blower 3 to make a liquid refrigerant. 4
Is a solenoid valve, which shuts off the flow path when the refrigerant leaks. Reference numeral 5 denotes a capillary tube which adiabatically expands and evaporates the liquid refrigerant. Reference numeral 6 denotes an intermediate heat exchanger, which takes heat from water and cools the refrigerant in a process of evaporating. The low-pressure gas refrigerant exiting the intermediate heat exchanger 6 is sucked into the compressor 1 through the accumulator 7. Here, the accumulator 7 is a buffer tank for preventing the liquid refrigerant not gasified in the intermediate heat exchanger 6 from directly returning to the compressor 1 in a large amount. The above refrigeration cycle is the first stage refrigeration cycle. A pump 8 sends water to the intermediate heat exchanger 6 to exchange heat with a first-stage refrigeration cycle using hydrocarbon as a refrigerant. The water cooled in the intermediate heat exchanger 6 cools the air in the cabin 20 blown by the indoor blower 10 in the indoor heat exchanger 9 and then returns to the pump. The above refrigeration cycle is the second stage refrigeration cycle. In the present embodiment, the refrigeration cycle including the first stage and the second stage described above is one system. However, the present invention is not limited to one system, and a plurality of systems may be provided according to the rated cooling capacity. combine. FIG. 2 is a plan view showing a state in which an upper cover of the air conditioner mounted on a roof is removed, and is an embodiment of an air conditioner including two refrigeration cycles. The outdoor blower 3 and the indoor blower 10 are each one, and have a blowing capacity for two systems. The outdoor blower 3 sucks in the outside air from directly above, similarly to the conventional air conditioner mounted on the roof, and blows the air to two outdoor heat exchangers 2 mounted diagonally.
The indoor blower 10 sucks the air in the guest room through the two indoor heat exchangers 9 and blows the air to the guest room directly below. The room where the equipment is placed is divided into three. An outdoor unit room in which a compressor 1, an outdoor heat exchanger 2, an outdoor blower 3, an electromagnetic valve 4, and an accumulator 7 are arranged, and an intermediate heat exchanger room in which a capillary tube 5, an intermediate heat exchanger 6, and a pump 8 are arranged; And an indoor unit room in which the indoor heat exchanger 9 and the indoor blower 10 are arranged. As shown in FIG. 3, a plurality of holes 15 are provided in a partition wall between the outdoor unit room and the intermediate heat exchanger room, so that the intermediate heat exchanger room is ventilated by the blower of the outdoor blower. An exhaust port 16 is also provided on the partition wall. This is because even if the refrigerant in the first stage refrigeration cycle leaks, the gas is diluted by the wind of the outdoor blower. The gas leak detection sensor 51 is mounted near the exhaust port 16 in the intermediate heat exchanger room. On the other hand, the partition wall between the intermediate heat exchanger room and the indoor unit room is completely isolated, so that even if the refrigerant of the first stage refrigeration cycle leaks, gas should not enter the indoor unit room side. I have. The rotation speed of the compressor 1 is controlled by the inverter 11. The controller 12 calculates an optimum rotation speed of the compressor based on sensor information such as an in-vehicle temperature sensor and outputs an operation frequency to the inverter. In FIG. 3, reference numeral 20 denotes a microcomputer which executes various calculations and comparisons and judgments in accordance with instructions of an execution program stored in a ROM (read only memory) 30. RAM (random access memory) 40
This is a place where various data is temporarily stored. Analog data detected by the in-vehicle temperature sensor 50 and the gas leak detection sensor 51 are converted into digital values by an A / D converter 54 and input to the microcomputer 20. Further, a thermal relay 60 of the compressor and a reset switch 61 provided in a switchboard in the vehicle are input to the microcomputer 20 via a digital input relay 62.
If the gas leaks from the intermediate heat exchanger 6, the gas concentration of the air flowing out from the exhaust port 16 to the outside increases, so that the gas leak can be reliably detected. In the case where gas leaks from pipes or devices arranged in the outdoor equipment room, the gas is diluted by the wind of the outdoor blower 3 and released to the outside as cooling air of the outdoor heat exchanger 2. Not detectable. Therefore, detection is indirectly performed by the thermal relay 60 of the compressor 1. When the refrigerant leaks, the temperature of the compressor 1 rises, and the thermal relay 60 attached to the surface of the compressor 1 operates to detect the rise in temperature. Microcomputer 2
The digital frequency command to the 0 inverter 11 is D / A
The voltage is converted by converter 70 and output to inverter 11. Inverter 11 operates compressor 1 at a frequency corresponding to the voltage command. Outdoor blower 3, solenoid valve 4,
The pump 8 and the indoor blower 10 are connected to a digital output relay 80.
The contactor 81 is turned on and off by the non-contact output of, and the operation is controlled. A gas leak detection lamp 91 provided in a switchboard in the vehicle is turned on by a lamp display circuit 90. Next, a detailed description will be given with reference to the flowchart shown in FIG.
Normally, the motor rotation speed of the compressor 1 is controlled by the inverter 11 based on the deviation between the detected vehicle interior temperature and the set temperature. However, as shown in F100 to F106, the gas concentration is detected by the gas leak detection sensor 51. If the gas concentration exceeds the reference value, the compressor 1 is stopped and the solenoid valve 5 is closed. The same applies when the thermal relay 60 operates. Since the suction port of the compressor 1 has a check valve,
The intermediate heat exchanger 5 is isolated from the outdoor heat exchanger 2 and minimizes gas leakage. In F105, the gas leak detection lamp 91 is turned on to indicate the failure to the crew, and the operation of the first stage refrigeration cycle is stopped until the reset switch 61 is input.

As described above, according to the present invention, in an air conditioner using a flammable refrigerant, even if the refrigerant leaks, it can be prevented from entering the passenger cabin, and the safety of passengers can be ensured. Can be. In addition, the leakage of the refrigerant can be minimized, and the refrigerant leaked by the wind of the outdoor blower can be diluted. As a result, the worst situation in which the leaked refrigerant explodes can be avoided.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle system diagram of one embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the air conditioner of the present invention.

FIG. 3 is a side view showing a frame structure of an intermediate heat exchanger room in FIG. 2;

FIG. 4 is a control block diagram of a controller in one embodiment of the air conditioner of the present invention.

FIG. 5 is a control flowchart in the controller of FIG. 4;

[Explanation of symbols]

1 ... Compressor, 2 ... Outdoor heat exchanger, 3 ... Outdoor blower, 4 ...
Solenoid valve, 5 ... capillary tube, 6 ... intermediate heat exchanger,
8: accumulator, 8: pump, 9: indoor heat exchanger,
10 ... indoor blower, 51 ... gas leak detection sensor, 60 ...
thermal relay.

Claims (3)

[Claims] 1. A first stage refrigeration cycle comprising a compressor, an outdoor heat exchanger, a solenoid valve for interrupting a flow path in response to refrigerant leakage, an intermediate heat exchanger, and using hydrocarbon as a refrigerant, and a pump. And a second stage refrigeration cycle using water as a refrigerant, comprising an intermediate heat exchanger, an indoor heat exchanger, and an indoor blower. 2. The air conditioner for a railway vehicle according to claim 1, wherein an intermediate heat exchanger room is provided between the outdoor unit room and the indoor unit room and is isolated from the indoor unit room. An air conditioner for a railway vehicle, wherein a plurality of holes are provided in a frame so as to flow outside through a heat exchanger room. 3. The air conditioner for a railway vehicle according to claim 1, wherein a gas leak detector is provided inside the intermediate heat exchanger room.
When a gas leak is detected, the compressor is stopped and the first
An air conditioner for a railway vehicle, wherein an electromagnetic valve of a tiered refrigeration cycle is closed to turn on an indicator lamp.