A tunnel refrigeration system

Abstract

The present invention discloses a tunnel refrigeration system, which solves the problems of poor efficiency of tunnel heat conduction caused by thin air in high altitude areas, excessive temperature difference before and after the tunnel, excessive temperature of equipment and leakage. The present invention includes an external circulation cooling water system leading to the tunnel, and the external circulation cooling water system includes an external water inlet pipe and an internal water outlet pipe extending in the tunnel. The external water inlet pipe leads the cooling water outside the tunnel to the cooling unit in the tunnel, and the internal water outlet pipe discharges the hot water after heat exchange with the cooling unit to the outside of the tunnel, so as to realize the circulation heat exchange of the cooling unit. The cooling unit includes a compressor, a heat exchanger, an expansion valve and an evaporator connected in a circulation manner. The refrigerant circulates between the compressor, the heat exchanger, the expansion valve and the evaporator to realize the evaporator absorbing heat and releasing heat through the heat exchanger. The external water inlet pipe and the internal water outlet pipe are connected to the compressor of the cooling unit through the heat exchanger, and then the external circulation cooling water system discharges the heat released by the heat exchanger to the outside of the tunnel.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction refrigeration, in particular to a tunnel refrigeration system. Background Art

[0002] At present, the tunnel refrigeration system generally uses external cooling water to cool the refrigerant of the compressor, the refrigerant cools the internal circulating water, and the internal circulating water cools the air. The refrigeration method is to pass cold air to the tunnel construction area, and cool the entire tunnel from the front of the tunnel to the back of the tunnel through heat conduction.

[0003] Problems with current tunnel refrigeration systems:

[0004] (1) The air density in high altitude areas is lower, and the heat exchange rate is lower than that in low altitude areas under the same temperature difference. The effect of heat transfer from the front end to the back end of the tunnel is poor.

[0005] (2) The temperature at the front end is lower and the temperature at the back end is higher. There are more working devices at the back end, which generate more heat, and a lower working temperature is required to keep the equipment working stably.

[0006] (3) The equipment is located in high altitude areas where the air is thin and the atmospheric pressure is low, so there is a leakage defect in the power supply circuit of the electrical equipment.

[0007] Since the heat exchange efficiency in the tunnel needs to be improved, the water supply temperature of the cooling water outside the tunnel needs to be kept low. Usually, the cooling outside the tunnel mainly relies on air cooling of the cooling water tower, which has low heat dissipation efficiency and the cooling water temperature is still high, which cannot meet the low temperature requirements of the cooling water temperature outside the tunnel. In particular, the plateau construction environment is quite different from that of low-altitude areas, especially the reduced air density, which leads to a serious decrease in the heat conduction efficiency in the tunnel. Summary of the invention

[0008] In view of the deficiencies in the above-mentioned background technology, the present invention proposes a tunnel refrigeration system, which solves the problems of poor efficiency of tunnel heat conduction caused by thin air in high-altitude areas, large temperature difference before and after the tunnel, high equipment temperature and leakage.

[0009] The technical solution of the present invention is implemented as follows: a tunnel refrigeration system includes an external circulation cooling water system leading to the tunnel, the external circulation cooling water system includes an external water inlet pipe and an internal water outlet pipe extending in the tunnel, and a plurality of cooling units are connected in parallel along the extension direction of the external water inlet pipe and the internal water outlet pipe to achieve cooling of the entire tunnel. The external water inlet pipe leads the cooling water outside the tunnel to the cooling unit in the tunnel, and the internal water outlet pipe discharges the hot water after heat exchange with the cooling unit to the outside of the tunnel, thereby achieving cyclic heat exchange of the cooling unit. The cooling unit includes a compressor, a heat exchanger, an expansion valve and an evaporator connected in a circulation manner. The refrigerant circulates among the compressor, the heat exchanger, the expansion valve and the evaporator to achieve heat absorption by the evaporator and heat release through the heat exchanger. The external water inlet pipe and the internal water outlet pipe are connected to the compressor of the cooling unit through the heat exchanger, and then the external circulation cooling water system discharges the heat released by the heat exchanger to the outside of the tunnel.

[0010] Furthermore, a fan is arranged opposite to the evaporator, and the fan cools down the air in the tunnel sufficiently and quickly through the evaporator, thereby improving the energy efficiency ratio.

[0011] Furthermore, a plurality of evaporators are connected in parallel between the heat exchanger and the compressor of the cooling unit, thereby further improving the refrigeration energy efficiency of each cooling unit.

[0012] Furthermore, a number of heat exchangers are arranged between the compressor and the evaporator of each cooling unit to ensure that sufficient cooling capacity is provided to the cooling unit so that the heat emitted by the cooling unit can be efficiently discharged out of the cave.

[0013] Furthermore, the external circulation cooling water system includes a return water tank and a cooling water tank outside the tunnel. The water inlet pipe outside the tunnel is connected to the cooling water tank outside the tunnel through an inlet pump, and the water outlet pipe inside the tunnel is connected to the return water tank. The return water tank and the cooling water tank outside the tunnel are connected through a lifting water pump and a cooling water tower. The cooling water tower can cool the water in the return water tank, and then further cool it through the cooling water tank outside the tunnel and circulate it to the cooling unit in the tunnel.

[0014] Furthermore, an outside pressure sensor, a one-way valve and an air pressure tank are arranged in sequence between the water inlet pump and the outside water inlet pipe in the tunnel to monitor and control the pressure of cooling water in the outside water inlet pipe.

[0015] Furthermore, the external cooling water tank is connected to an external refrigeration unit, which includes an external evaporator arranged in the external cooling water tank, an external compressor and an external heat exchanger are connected to both ends of the external evaporator, a fan is arranged corresponding to the external heat exchanger, and an external expansion valve is arranged between the external heat exchanger and the external evaporator. The external refrigeration unit can further cool the cold water in the external cooling water tank, so that the temperature of the cooling water entering the tunnel is low enough.

[0016] Furthermore, a first filter and a descaling device are provided between the water inlet pipe outside the cave and the heat exchanger, and a second filter is provided between the heat exchanger and the evaporator to reduce scaling inside the heat exchanger and improve heat exchange efficiency.

[0017] Furthermore, a sight glass and a solenoid valve are provided between the second filter and the expansion valve, and a ball valve and a first needle valve are provided between the second filter and the heat exchanger.

[0018] A pressure sensor, a second needle valve, a pressure gauge and a pressure difference switch are arranged between the evaporator and the compressor.

[0019] A temperature sensor, a pressure difference switch, a pressure gauge and a third needle valve are arranged between the compressor and the heat exchanger.

[0020] The heat exchanger is a shell and tube heat exchanger, the compressor is a screw compressor, and the evaporator is a finned evaporator.

[0021] The present invention can effectively reduce the temperature at the rear of the tunnel, strengthen the heat conduction from the front end of the tunnel to the rear of the tunnel, and prevent the temperature at the rear of the tunnel from being too high due to too many equipment, causing equipment failure and discomfort to personnel. In addition, the external circulation adopts a water cooling system, and the internal circulation adopts a refrigerant compressor unit to exchange heat with the external circulation, avoiding the construction safety hazards caused by leakage hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0023] Figure 1 For the cooling unit in the tunnel;

[0024] Figure 2 It is an external circulation cooling water system;

[0025] Figure 1 Middle: 1-evaporator, 2-expansion valve, 3-solenoid valve, 4-sight glass, 5-second filter, 6-first needle valve, 7-ball valve, 8-heat exchanger, 9-descaler, 10-second filter, 11-pressure sensor, 12-second needle valve, 13-pressure gauge, 14-differential pressure switch, 15-compressor, 16-temperature sensor;

[0026] Figure 2In: 17-air pressure tank, 18-check valve, 19-pressure sensor outside the cave, 20-water inlet pump, 21-lifting water pump, 22-flow controller, 23-cooling water tower, 24-heat exchanger outside the cave, 25-compressor outside the cave, 26-expansion valve outside the cave, 27-evaporator outside the cave, 28-cooling water tank outside the cave, 29-water inlet pipe outside the cave, 30-water outlet pipe inside the cave, 31-return water tank. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] A tunnel refrigeration system, such as Figure 1 and Figure 2 As shown, it includes an external circulation cooling water system leading to the tunnel. The external circulation cooling water system includes an external water inlet pipe 29 and an internal water outlet pipe 30 extending in the tunnel. A number of cooling units are connected in parallel along the extension direction of the external water inlet pipe 29 and the internal water outlet pipe 30. Each group of cooling units is arranged at intervals of 100m. The heat in the tunnel is absorbed by the cooling unit, and then the heat of the cooling unit is discharged through the external water inlet pipe 29 and the internal water outlet pipe 30, thereby achieving cooling of the entire tunnel.

[0029] The external circulation cooling water system includes a return water tank 31 and an external cooling water tank 28 located outside the tunnel. The external water inlet pipe 29 is connected to the external cooling water tank 28 through the water inlet pump 20, and the internal water outlet pipe 30 is connected to the return water tank 31. The return water tank 31 and the external cooling water tank 28 are connected through the lifting water pump 21, the flow controller 22 and the cooling water tower 23. The cooling water tower 23 can cool the water in the return water tank 31, and then further cool it through the external cooling water tank 28 and circulate it to the cooling unit in the tunnel. The external water inlet pipe 29 passes the cooling water outside the tunnel to the cooling unit in the tunnel, and the internal water outlet pipe 30 discharges the hot water after heat exchange with the cooling unit to the outside of the tunnel, so as to realize the circulation heat exchange of the cooling unit.

[0030] Furthermore, an outside pressure sensor 19, a one-way valve 18 and an air pressure tank 17 are sequentially arranged between the water inlet pump 20 and the outside water inlet pipe 1 in the tunnel to monitor and control the pressure of cooling water in the outside water inlet pipe 1.

[0031] Furthermore, the outer cooling water tank 28 is connected to an external refrigeration unit, which includes an outer evaporator 27 arranged in the outer cooling water tank 28, and the outer compressor 25 and the outer heat exchanger 24 are connected at both ends of the outer evaporator 27. A fan is arranged corresponding to the outer heat exchanger 24, and an outer expansion valve 26 is arranged between the outer heat exchanger 24 and the outer evaporator 27. The refrigerant evaporates and absorbs heat in the outer evaporator 27, and is used to cool the cooling water in the outer cooling water tank 28. The outer evaporator 27 transports the refrigerant to the outer compressor 25 for compression into liquid state, and the outer compressor 25 transports the refrigerant to the outer heat exchanger 24 to cool the refrigerant. The refrigerant passes through the outer expansion valve 26 and reaches the outer evaporator 27, forming a cooling unit. The external refrigeration unit can further cool the cold water in the outer cooling water tank 31, so that the temperature of the cooling water entering the tunnel is low enough.

[0032] The cooling unit includes a compressor 15, a heat exchanger 8, an expansion valve 2 and an evaporator 1 which are circulated. The refrigerant circulates among the compressor 15, the heat exchanger 8, the expansion valve 2 and the evaporator 1, so that the evaporator 1 absorbs the heat in the tunnel and discharges the absorbed heat through the heat exchanger 8. The water inlet pipe 29 outside the tunnel and the water outlet pipe 30 inside the tunnel are connected to the compressor 15 of the cooling unit through the heat exchanger 8, and then the external circulation cooling water system discharges the heat released by the heat exchanger 8 outside the tunnel.

[0033] When the system is working, the cooling water passes through the Y-type filter and the electronic descaling device, enters the heat exchanger 8 and exchanges heat with the high-temperature refrigerant compressed by the compressor 15. The cooled refrigerant is combined and divided into four groups to enter the expansion valve 2 and the evaporator 1. The refrigerant evaporates and absorbs heat, and the external air exchanges heat with the evaporator 1 to reduce the temperature in the tunnel. The refrigerants of the four groups of evaporators 1 are combined and enter the compressor 15. The screw compressor compresses the gaseous refrigerant into liquid, and then the refrigerant enters the heat exchanger 8 for cooling. This is a complete thermal cycle process.

[0034] Furthermore, a fan is arranged opposite to the evaporator 1, and the fan cools down the air in the tunnel sufficiently and quickly through the evaporator 1, thereby improving the energy efficiency ratio.

[0035] Furthermore, four evaporators 1 are connected in parallel between the heat exchanger 8 and the compressor 15 of the cooling unit, further improving the refrigeration efficiency of each cooling unit. Two heat exchangers 8 are arranged between the compressor 15 and the evaporator 1 of each cooling unit to ensure that sufficient cooling capacity is provided for the cooling unit, so that the heat emitted by the cooling unit is efficiently discharged out of the cave.

[0036] Furthermore, a first filter 10 and a descaling device 9 are provided between the water inlet pipe 1 outside the cave and the heat exchanger 8, and a second filter 5 is provided between the heat exchanger 8 and the evaporator 1 to reduce scaling inside the heat exchanger 8 and improve heat exchange efficiency.

[0037] Furthermore, a sight glass 4 and a solenoid valve 3 are provided between the second filter 5 and the expansion valve 2, and a ball valve 7 and a first needle valve 6 are provided between the second filter 5 and the heat exchanger 8. A pressure sensor 11, a second needle valve 12, a pressure gauge 13 and a pressure differential switch 14 are provided between the evaporator 1 and the compressor 15. A temperature sensor 16, a pressure differential switch 14, a pressure gauge 13 and a third needle valve are provided between the compressor 15 and the heat exchanger 8. The heat exchanger 8 is a shell and tube heat exchanger, the compressor 15 is a screw compressor, and the evaporator 1 is a finned evaporator.

[0038] The pumps involved in the present invention are all variable frequency pumps, and the parts not described in detail in the present invention are all conventional technical means known to those skilled in the art.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A tunnel refrigeration system, comprising an external circulation cooling water system leading to the tunnel, characterized in that: The external circulation cooling water system comprises an external water inlet pipe (29) and an internal water outlet pipe (30) extending in the tunnel, a plurality of cooling units are connected in parallel along the extending direction of the external water inlet pipe (29) and the internal water outlet pipe (30), the cooling unit comprising a compressor (15), a heat exchanger (8), an expansion valve (2) and an evaporator (1) which are cyclically connected, and the external water inlet pipe (29) and the internal water outlet pipe (30) are connected to the compressor (15) of the cooling unit via the heat exchanger (8); A fan is arranged opposite to the evaporator (1); A plurality of evaporators (1) are connected in parallel between the heat exchanger (8) and the compressor (15) of the cooling unit; A plurality of heat exchangers (8) are provided between the compressor (15) and the evaporator (1) of each cooling unit; The external circulation cooling water system comprises a return water tank (31) and an external cooling water tank (28) located outside the cave, the return water tank (31) and the external cooling water tank (28) being connected via a lifting water pump (21) and a cooling water tower (23), the external water inlet pipe (29) being connected to the external cooling water tank (28) via an inlet pump (20), and the internal water outlet pipe (30) being connected to the return water tank (31); The external cooling water tank (28) is connected to an external refrigeration unit, the external refrigeration unit comprising an external evaporator (27) arranged in the external cooling water tank (28), the external evaporator (27) being connected to an external compressor (25) and an external heat exchanger (24) at both ends, a fan being arranged corresponding to the external heat exchanger (24), and an external expansion valve (26) being arranged between the external heat exchanger (24) and the external evaporator (27); a pressure sensor (11), a second needle valve (12), a pressure gauge (13) and a pressure differential switch (14) being arranged between the evaporator (1) and the compressor (15); A temperature sensor (16), a pressure difference switch (14), a pressure gauge (13) and a third needle valve are provided between the compressor (15) and the heat exchanger (8); The heat exchanger (8) is a shell and tube heat exchanger, the compressor (15) is a screw compressor, and the evaporator (1) is a finned evaporator.

2. The tunnel refrigeration system according to claim 1, characterized in that: An external pressure sensor (19), a one-way valve (18) and an air pressure tank (17) are sequentially arranged between the water inlet pump (20) and an external water inlet pipe (29) in the tunnel.

3. The tunnel refrigeration system according to any one of claims 1-2, characterized in that: A first filter (10) and a descaling device (9) are provided between the external water inlet pipe (29) and the heat exchanger (8), and a second filter (5) is provided between the heat exchanger (8) and the evaporator (1).

4. The tunnel refrigeration system according to claim 3, characterized in that: A sight glass (4) and a solenoid valve (3) are provided between the second filter (5) and the expansion valve (2), and a ball valve (7) and a first needle valve (6) are provided between the second filter (5) and the heat exchanger (8).

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