Refrigerating system capable of achieving rapid defrosting and provided with at least two surface air coolers

Abstract

The utility model discloses a refrigerating system with at least two surface air coolers, which can realize quick defrosting and comprises a refrigerating evaporator, at least two surface air coolers, a cold oil pipeline, a hot oil storage tank, a circulating heating pipeline and a hot oil pipeline, a cold oil pipe switch valve is arranged on a pipeline, connected with each surface air cooler, of the cold oil pipeline, a first pipeline heater is arranged on the cyclic heating pipeline, a secondary refrigerant in the hot oil storage tank can circularly pass through the cyclic heating pipeline to be heated, and the hot oil storage tank is connected with each surface air cooler through the hot oil pipeline. A hot oil pipe switch valve is arranged on a pipeline, connected with each surface air cooler, of the hot oil pipeline, and a cold oil constant-pressure tank is connected to the cold oil pipeline. The defrosting efficiency of the multiple surface air coolers in the refrigerating system is high, and the influence on the environment temperature is small.

Description

Technical Field

[0001] The utility model relates to the technical field of defrosting of a surface cooler in a refrigeration system, in particular to a refrigeration system with at least two surface coolers capable of realizing rapid defrosting. Background Art

[0002] With the increase in social demand, the testing and test rooms of refrigeration systems with various special needs have developed rapidly. Faced with the most common frosting problem in refrigeration systems, the disadvantages exposed by traditional refrigerant defrosting solutions are more obvious, such as: 1. The reversing reverse cycle defrosting method has the following problems: long time consumption, high energy consumption, insufficient energy source, uneven defrosting, etc.; 2. The electric heating defrosting method has the following problems: large electricity consumption, part of the heat will dissipate to the surrounding cold environment during defrosting, which increases energy consumption and reduces defrosting efficiency. At the same time, the life of the heating wire or heat pipe is short, and there are safety hazards. Especially in the refrigeration system, electric heating defrosting has a greater impact on the temperature field of the low-temperature cold storage, etc.; 3. The hot refrigerant defrosting method has the following problems: it uses the high-temperature refrigerant gas discharged from the refrigeration compressor and the refrigerant to heat and defrost, which has a greater impact on the ambient temperature of the test chamber and requires the refrigeration process to be interrupted.

[0003] In this context, for refrigeration systems with surface coolers, we have designed a technical solution that can achieve rapid defrosting. It can avoid the problems caused by the above-mentioned existing defrosting methods, such as interruption of the refrigeration process, significant impact on the ambient temperature, and low defrosting efficiency, and better ensure the stable operation of the system. Utility Model Content

[0004] The utility model aims to provide a refrigeration system with at least two surface coolers which can realize rapid defrosting.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] A refrigeration system with at least two surface coolers capable of achieving rapid defrosting, comprising a refrigeration evaporator, at least two surface coolers and a cold oil pipeline, the refrigeration evaporator being connected to each surface cooler respectively through the cold oil pipeline, and a cold oil pipeline switching valve being provided on the pipe of the cold oil pipeline connected to each surface cooler respectively. The system is characterized in that it also comprises a hot oil storage tank, a circulating heating pipeline and a hot oil pipeline, a first pipeline heater being provided on the circulating heating pipeline, the refrigerant in the hot oil storage tank being able to circulate through the circulating heating pipeline for heating, the hot oil storage tank being connected to each surface cooler respectively through the hot oil pipeline, a hot oil pipeline switching valve being provided on the pipe of the hot oil pipeline connected to each surface cooler respectively, and a cold oil constant pressure tank being connected to the cold oil pipeline.

[0007] A further technical solution of the present invention is as follows: the hot oil pipeline includes a hot oil supply main circuit, a hot oil supply branch circuit corresponding to each surface cooler, a hot oil return main circuit and a hot oil return branch circuit corresponding to each surface cooler, the input end of the hot oil supply main circuit and the output end of the hot oil return main circuit are respectively connected to the hot oil output port and the first hot oil return port of the hot oil storage tank, the input end of the hot oil supply branch circuit and the output end of the hot oil return branch circuit are respectively connected to the hot oil supply main circuit and the hot oil return main circuit, the output end of the hot oil supply branch circuit is respectively connected to the input port of the corresponding surface cooler, the input end of the hot oil return branch circuit is respectively connected to the output end of the corresponding surface cooler, and a hot oil pipe switch valve is respectively provided on the hot oil supply branch circuit and the hot oil return branch circuit.

[0008] A further technical solution of the utility model is: a first water pump is also provided on the circulating heating pipeline, the input end of the circulating heating pipeline is connected to the hot oil output port of the hot oil storage tank, the output end of the circulating heating pipeline is respectively connected to the input end of the hot oil supply main circuit and the second hot oil return port of the hot oil storage tank, and a circulation control switch valve is provided on the pipeline connecting the output end of the circulating heating pipeline and the second hot oil return port.

[0009] A further technical solution of the present invention is: a first temperature sensor for measuring the temperature of the internal coolant is provided on the hot oil storage tank, and a second temperature sensor for measuring the temperature of the coolant in the pipe is provided at the output end of the circulating heating pipeline.

[0010] A further technical solution of the present invention is that a liquid level sensor for measuring the internal coolant liquid level is provided on the hot oil storage tank.

[0011] A further technical solution of the utility model is that the hot oil storage tank is a constant pressure tank.

[0012] A further technical solution of the present invention is that a third temperature sensor is respectively provided at the output end of each surface cooler.

[0013] A further technical solution of the present invention is as follows: the cold oil pipeline includes a cold oil supply main circuit, a cold oil supply branch circuit respectively arranged corresponding to each surface cooler, a cold oil return main circuit and a cold oil return branch circuit respectively arranged corresponding to each surface cooler; the input end of the cold oil supply main circuit and the output end of the cold oil return main circuit are respectively connected to the cold oil output port and the cold oil return port of the refrigeration evaporator; the input end of the cold oil supply branch circuit and the output end of the cold oil return branch circuit are respectively connected to the cold oil supply main circuit and the cold oil return main circuit; the output end of the cold oil supply branch circuit is respectively connected to the input port of the corresponding surface cooler; the input end of the cold oil return branch circuit is respectively connected to the output end of the corresponding surface cooler; and cold oil pipe switch valves are respectively arranged on the cold oil supply branch circuit and the cold oil return branch circuit.

[0014] A further technical solution of the utility model is: a mixing branch is provided between the cold oil supply main circuit and the cold oil return main circuit, the input end of the mixing branch is connected to the cold oil return main circuit, and the output end of the mixing branch is connected to the cold oil supply main circuit through a three-way regulating valve.

[0015] A further technical solution of the present invention is as follows: a second pipe heater and a fourth temperature sensor for detecting the temperature of the refrigerant in the pipe are provided on the cold oil return main line, and the refrigeration system is further provided with a fifth temperature sensor for detecting the indoor temperature.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The utility model is additionally provided with a hot oil storage tank, a circulating heating pipeline and a hot oil pipeline. Before defrosting, the circulating heating pipeline can be used to preheat the refrigerant in the hot oil storage tank to a set temperature. When the surface cooler needs to be defrosted, the refrigerant in the hot oil storage tank that has been heated to the set temperature is sent into the surface cooler, so that fast defrosting can be achieved without waiting for heating, and the efficiency is high.

[0018] 2. The refrigeration evaporator and hot oil storage tank of the utility model are respectively connected to each surface cooler, and the inlet and outlet of the refrigerant of each surface cooler can be controlled separately, so that a single surface cooler can be defrosted in turn while other surface coolers work normally to maintain the indoor ambient temperature, thereby ensuring the indoor cooling demand and greatly reducing the impact of the defrosting process on the ambient temperature.

[0019] 3. The cold oil pipeline and the hot oil pipeline of the utility model are independent of each other, and the hot oil storage tank can be further set as a constant pressure tank, so that there are constant pressure tanks on both the cold oil pipeline and the hot oil pipeline, that is, a double constant pressure tank is introduced, which can better ensure the independent and stable operation of each. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The utility model is a schematic structural diagram of a refrigeration system with four surface coolers capable of achieving rapid defrosting according to an embodiment of the present invention.

[0021] Meaning of the reference numerals in the figure:

[0022] 1-Refrigeration evaporator; 2-Cold oil constant pressure tank; 3-Second water pump; 4-Mixing branch; 5-Three-way regulating valve; 6-Fifth temperature sensor; 7-Fourth temperature sensor; 8-Second pipe heater; 9-Cold oil return main line; 10-Cold oil supply main line; 11-Cold oil supply branch line; 12-Cold oil return branch line; 13-Cold oil pipe on-off valve; 14-Surface cooler; 15-Third temperature sensor; 16-Hot oil pipe on-off valve; 17-Hot oil return branch line; 18-Hot oil supply branch line; 19-Hot oil return main line; 20-Hot oil supply main line; 21-First pipe heater; 22-Second temperature sensor; 23-First water pump; 24-First temperature sensor; 25-Hot oil storage tank; 26-Circulation control on-off valve; 27-Main circuit; 28-Flowmeter; 29-Pressure sensor; 30-Circulating heating pipeline; 31-Third water pump DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the embodiments.

[0024] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0025] In the description of this utility model, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0026] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0027] Example:

[0028] like Figure 1 The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to this embodiment includes a refrigeration evaporator 1, four surface coolers 14, a cold oil pipeline, a hot oil storage tank 25, a circulating heating pipeline 30 and a hot oil pipeline.

[0029] Four surface coolers 14 are arranged in a matrix. The refrigeration evaporator 1 is connected to each surface cooler 14 via a cooling oil pipeline. A cooling oil pipe switching valve 13 is installed on each cooling oil pipe connecting to the surface cooler 14. The cooling oil pipe switching valve 13 controls the connection between the surface cooler 14 and the cooling oil pipeline. The refrigeration evaporator 1 is also connected to the refrigeration system's main circuit 27.

[0030] The specific structure of the cooling oil pipeline is as follows: it includes a cooling oil main supply line 10, four cooling oil supply branches 11, a cooling oil return main line 9, and four cooling oil return branches 12. The four cooling oil supply branches 11 and the four cooling oil return branches 12 are respectively provided for four surface coolers 14. The input end of the cooling oil main supply line 10 and the output end of the cooling oil return main line 9 are respectively connected to the cooling oil output port and cooling oil return port of the refrigeration evaporator 1. The input end of the cooling oil supply branch 11 and the output end of the cooling oil return branch 12 are respectively connected to the cooling oil main supply line 10 and the cooling oil return main line 9. The output end of the cooling oil supply branch 11 is respectively connected to the input port of the corresponding surface cooler 14, and the input end of the cooling oil return branch 12 is respectively connected to the output port of the corresponding surface cooler 14. The cooling oil pipe switching valve 13 is respectively provided on the cooling oil supply branch 11 and the cooling oil return branch 12. The cold oil pipe on-off valve 13 of this embodiment is a pneumatic on-off valve. By controlling the cold oil pipe on-off valve 13 , the input and output of each surface cooler 14 can be controlled.

[0031] In this embodiment, a cooling oil constant pressure tank 2 and a second water pump 3 are connected to the cooling oil return main path 9 of the cooling oil pipeline.

[0032] In this embodiment, a mixing branch 4 is provided between the main cold oil supply line 10 and the main cold oil return line 9. The input end of the mixing branch 4 is connected to the main cold oil return line 9, and the output end of the mixing branch 4 is connected to the main cold oil supply line 10 via a three-way regulating valve 5. The three-way regulating valve 5 is a pneumatic three-way regulating valve. By controlling the three-way regulating valve 5, the flow rate of the brine in the main cold oil return line 9 to the main cold oil supply line 10 for mixing can be controlled. A second pipe heater 8 is provided on the main cold oil return line 9, located closer to the surface cooler 14 than the connection point between the mixing branch and the main cold oil return line 9. The main cold oil supply line 10 is provided with a third water pump 31 and a fourth temperature sensor 7 for detecting the temperature of the brine in the pipe. The fourth temperature sensor 7 is located closer to the surface cooler 14 than the connection point between the mixing branch and the main cold oil supply line 10. The refrigeration system also includes a fifth temperature sensor 6 for detecting the temperature inside the cabin. In subsequent use, the power of the second pipe heater 8 and the opening of the three-way regulating valve 5 can be controlled by comparing the temperatures of the fourth temperature sensor 7 and the fifth temperature sensor 6, thereby better controlling the refrigerant temperature in the cold oil pipeline. The structures of the above-mentioned cold oil supply main line 10, cold oil return main line 9, and mixing branch line 4 all adopt conventional structures.

[0033] This refrigeration system adds a hot oil storage tank 25, a circulating heating pipeline 30, and a hot oil pipeline to the above structure. The hot oil storage tank 25 of this embodiment adopts a constant pressure tank, so that there are constant pressure tanks on both the cold oil pipeline and the hot oil pipeline, that is, a dual constant pressure tank is introduced, which can better ensure the independent and stable operation of each.

[0034] The hot oil pipeline of this embodiment includes a hot oil supply main line 20, four hot oil supply branches 18, a hot oil return main line 19 and four hot oil return branches 17. The four hot oil supply branches 18 and the four hot oil return branches 17 are respectively provided corresponding to the four surface coolers 14.

[0035] Among them, the circulating heating pipeline 30 is provided with a first pipe heater 21 and a first water pump 23, the input end of the circulating heating pipeline 30 is connected to the hot oil output port of the hot oil storage tank 25, and the output end of the circulating heating pipeline 30 is respectively connected to the input end of the hot oil supply main line 20 and the second hot oil return port of the hot oil storage tank 25, and a circulation control switch valve 26 is provided on the pipeline connecting the output end of the circulating heating pipeline 30 and the second hot oil return port.

[0036] In this embodiment, a first temperature sensor 24 for measuring the internal brine temperature and a level sensor for measuring the internal brine level are installed on the hot oil storage tank 25. A second temperature sensor 22 for measuring the brine temperature within the pipe is installed at the output end of the circulating heating pipeline 30. During subsequent use, the power of the first pipe heater 21 can be controlled by comparing the temperatures of the first temperature sensor 24 and the second temperature sensor 22.

[0037] Among them, the output end of the hot oil return main path 19 is connected to the first hot oil return port of the hot oil storage tank 25, the input end of the hot oil supply branch 18 and the output end of the hot oil return branch 17 are respectively connected to the hot oil supply main path 20 and the hot oil return main path 19, the output end of the hot oil supply branch 18 is respectively connected to the input port of the corresponding surface cooler 14, and the input end of the hot oil return branch 17 is respectively connected to the output end of the corresponding surface cooler 14. Hot oil pipe switch valves 16 are respectively provided on the hot oil supply branch 18 and the hot oil return branch 17. By controlling the hot oil pipe switch valve 16, the input and output of each surface cooler 14 can be controlled respectively.

[0038] In this embodiment, a third temperature sensor 15 is provided at the output end of each cooler 14 .

[0039] In this embodiment, pressure sensors 29 are provided on the circulating heating pipeline 30 , the cold oil supply main line 10 , the cold oil return main line 9 , and the like, and a flow meter 28 is provided on the cold oil return main line 9 .

[0040] When defrosting the coolers 14, the refrigeration system of this embodiment defrosts all of them in a rotating defrosting process. Specifically, each time, only one cooler 14 is disconnected from the cold oil line and connected to the hot oil line. This cooler 14 is then defrosted using the refrigerant heated to a set temperature in the hot oil tank 25. After defrosting is complete, the cooler is reconnected to the cold oil line and disconnected from the hot oil line, resuming normal operation. The next cooler is then defrosted.

[0041] The specific defrosting process is as follows:

[0042] During normal cooling of the refrigeration system without defrosting, the hot oil pipe switch valve 16 is closed, the cold oil pipe switch valve 13 is open, the second water pump 3 and the third water pump 31 are turned on, and the four surface coolers 14 operate normally.

[0043] When the refrigerant in the hot oil storage tank 25 needs to be heated in advance before defrosting, the circulation control switch valve 26 is opened, and the first pipe heater 21 and the first water pump 23 of the circulation heating pipeline 30 are turned on. Under the action of the first water pump 23, the refrigerant in the hot oil storage tank 25 will circulate through the circulation heating pipeline 30 and be heated by the first pipe heater 21. When the temperature of the second temperature sensor 22 at the output end of the circulation heating pipeline 30 is greater than the set temperature, the first pipe heater 21 is stopped.

[0044] When it is necessary to defrost the coolers 14 in turn, the cold oil pipe on-off valve 13 on the cold oil supply branch 11 connected to the first cooler is closed, the hot oil pipe on-off valve 16 on the hot oil supply branch 18 connected to the first cooler is opened, and the circulation control on-off valve 26 is closed. The brine in the hot oil storage tank 25 will enter the first cooler through the hot oil pipeline. The cooler brine in the first cooler will first be driven back to the cold oil constant pressure tank 2 of the cold oil pipeline through the cold oil return branch 12. After the drive is completed, since the temperature of the first cooler is initially lower, the hot brine in the hot oil storage tank 25 will quickly drop to a lower temperature upon entering the first cooler. Therefore, the cooler brine flowing out of the output end of the first cooler is still allowed to flow through the cold oil return branch 12 to the cold oil pipeline. After a period of time, when the liquid level in the hot oil storage tank 25 drops to the set liquid level, the temperature of the refrigerant flowing out of the output end of the first cooler has also risen to a certain temperature. At this time, the cold oil pipe switch valve 13 on the cold oil return branch 12 connected to the first cooler is closed, and the hot oil pipe switch valve 16 on the hot oil return branch 17 connected to the first cooler is opened, so that the refrigerant in the hot oil storage tank 25 circulates through the first cooler for defrosting.

[0045] After defrosting the first cooler, circulation control on / off valve 26 is opened, hot oil pipe on / off valve 16 on hot oil supply branch 18 connected to the first cooler is closed, and cold oil pipe on / off valve 13 on cold oil supply branch 11 connected to the first cooler is opened. The coolant in the cold oil pipe enters the first cooler and is expelled to hot oil storage tank 25. After expelling, the coolant in the cold oil pipe rapidly heats up after flowing into the first cooler, as the temperature of the first cooler is initially higher. Therefore, the higher-temperature coolant flowing out of the output end of the first cooler is further fed into the hot oil pipe. After a period of time, when the liquid level in the hot oil storage tank 25 rises and returns to the set liquid level, the temperature of the refrigerant flowing out of the output end of the first surface cooler has also dropped to a certain temperature. At this time, the hot oil pipe switch valve 16 on the hot oil return branch 17 connected to the first surface cooler is closed, and the cold oil pipe switch valve 13 on the cold oil return branch 12 connected to the first surface cooler is opened, so that the first surface cooler resumes normal operation.

[0046] Then, the above process is repeated to defrost the second to fourth surface coolers in sequence, thereby completing the defrosting work of all surface coolers.

[0047] The above embodiments of the present invention are not intended to limit the scope of protection of the present invention, and the implementation methods of the present invention are not limited thereto. All other modifications, replacements or changes made to the above structure of the present invention based on the above contents of the present invention, in accordance with common technical knowledge and customary means in this field, without departing from the above basic technical ideas of the present invention, should fall within the scope of protection of the present invention.

Claims

1. A refrigeration system with at least two surface coolers capable of rapid defrosting, comprising a refrigeration evaporator, at least two surface coolers, and a cooling oil pipeline, wherein the refrigeration evaporator is connected to each of the surface coolers via the cooling oil pipeline, and a cooling oil pipeline switching valve is provided on each pipe of the cooling oil pipeline connected to each of the surface coolers, characterized in that: It also includes a hot oil storage tank, a circulating heating pipeline and a hot oil pipeline. The circulating heating pipeline is provided with a first pipeline heater. The refrigerant in the hot oil storage tank can circulate through the circulating heating pipeline for heating. The hot oil storage tank is connected to each of the surface coolers through the hot oil pipeline. Hot oil pipe switching valves are respectively provided on the pipes of the hot oil pipeline connected to each of the surface coolers. A cold oil constant pressure tank is connected to the cold oil pipeline.

2. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 1, characterized in that: The hot oil pipeline includes a hot oil supply main line, a hot oil supply branch line corresponding to each of the coolers, a hot oil return main line and a hot oil return branch line corresponding to each of the coolers. The input end of the hot oil supply main line and the output end of the hot oil return main line are respectively connected to the hot oil output port and the first hot oil return port of the hot oil storage tank, the input end of the hot oil supply branch line and the output end of the hot oil return branch line are respectively connected to the hot oil supply main line and the hot oil return main line, the output end of the hot oil supply branch line is respectively connected to the input port of the corresponding cooler, the input end of the hot oil return branch line is respectively connected to the output end of the corresponding cooler, and the hot oil pipe switch valve is respectively provided on the hot oil supply branch and the hot oil return branch.

3. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 2, characterized in that: A first water pump is also provided on the circulating heating pipeline. The input end of the circulating heating pipeline is connected to the hot oil output port of the hot oil storage tank. The output end of the circulating heating pipeline is respectively connected to the input end of the hot oil supply main road and the second hot oil return port of the hot oil storage tank. A circulation control switch valve is provided on the pipeline connecting the output end of the circulating heating pipeline and the second hot oil return port.

4. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 1, characterized in that: The hot oil storage tank is provided with a first temperature sensor for measuring the temperature of the internal coolant, and the output end of the circulating heating pipeline is provided with a second temperature sensor for measuring the temperature of the coolant in the pipeline.

5. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 1, characterized in that: The hot oil storage tank is provided with a liquid level sensor for measuring the internal coolant liquid level.

6. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 1, characterized in that: The hot oil storage tank is a constant pressure tank.

7. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 1, characterized in that: A third temperature sensor is provided at the output end of each of the surface coolers.

8. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 1, characterized in that: The cold oil pipeline includes a cold oil supply main line, a cold oil supply branch line corresponding to each of the surface coolers, a cold oil return main line and a cold oil return branch line corresponding to each of the surface coolers. The input end of the cold oil supply main line and the output end of the cold oil return main line are respectively connected to the cold oil output port and the cold oil return port of the refrigeration evaporator, the input end of the cold oil supply branch line and the output end of the cold oil return branch line are respectively connected to the cold oil supply main line and the cold oil return main line, the output end of the cold oil supply branch line is respectively connected to the input port of the corresponding surface cooler, the input end of the cold oil return branch line is respectively connected to the output end of the corresponding surface cooler, and the cold oil pipe switch valve is respectively provided on the cold oil supply branch and the cold oil return branch.

9. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 8, characterized in that: A mixing branch is provided between the cold oil supply main circuit and the cold oil return main circuit, the input end of the mixing branch is connected to the cold oil return main circuit, and the output end of the mixing branch is connected to the cold oil supply main circuit through a three-way regulating valve.

10. The refrigeration system with at least two surface coolers capable of achieving rapid defrosting according to claim 9, characterized in that: The cold oil return main line is provided with a second pipe heater and a fourth temperature sensor for detecting the temperature of the refrigerant in the pipe. The refrigeration system is also provided with a fifth temperature sensor for detecting the temperature in the cabin.

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