Refrigeration system and control method for refrigerated truck and refrigerated truck

Abstract

The present invention discloses a refrigeration system, a control method and a refrigerated vehicle for a refrigerated vehicle. The refrigeration system includes a cold storage plate and a refrigeration unit. The cold storage plate is provided with a first evaporator and a first heat exchanger. The first heat exchanger, a circulating pump and a second heat exchanger form a cold release circuit through a refrigerant. The refrigeration system includes a first evaporator and a second evaporator. A second throttle valve is provided between the two. A branch is led out from the front end of the second throttle valve, on which a cold charging solenoid valve is provided. The outlet of the branch merges with the outlet pipe of the second evaporator. The present invention connects the refrigeration circuit and the cold release circuit together through a cold storage plate, which can not only meet the temperature requirements of the refrigerated vehicle for transporting different goods, but also improve the cruising range of the refrigerated vehicle.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and in particular to a refrigeration system and a control method for a refrigerated truck, and the refrigerated truck. Background Art

[0002] Cold storage refrigerated trucks rely on cold storage plates to continuously release cold to maintain the temperature of the box. They do not require refrigeration units and have a simple structure, but their refrigeration capacity is limited, and the phase change temperature of the cold storage plate is fixed and the temperature is uncontrollable, which cannot meet the diverse transportation needs of refrigerated trucks. If you want to transport different goods, you need to replace the cold storage liquid inside the cold storage plate, which is extremely inconvenient. At present, there are some solutions that combine refrigeration units and cold storage plates. Cold storage plates and refrigeration units are carried on refrigerated trucks at the same time. The cold storage plates are charged with cold before transportation. When in use, the cold storage plates are used to release cold first. After the cold storage plates are completely released, the unit is used for refrigeration. This method can expand the temperature range of the refrigerated truck, but after exceeding the phase change temperature range of the cold storage plate, the cold storage plate cannot be used, and only the unit refrigeration can be used to provide cold air for the refrigerated truck. Therefore, the existing cold storage refrigerated trucks have the problems of short cruising range and the inability of the cold storage plates to meet different temperature requirements. Summary of the invention

[0003] The present invention provides a refrigeration system, a control method and a refrigerated truck for a refrigerated truck, so as to solve the problems of short cruising range and inability of the cold storage plate to meet different temperature requirements in the existing cold storage refrigerated truck.

[0004] The refrigeration system for a refrigerated vehicle proposed in the present invention includes a cold storage plate and a refrigeration unit, wherein a first evaporator and a first heat exchanger are provided on the cold storage plate, and the first heat exchanger, a circulating pump and a second heat exchanger form a cold release circuit through a coolant; the refrigeration system includes a first evaporator and a second evaporator, a second throttle valve is provided therebetween, a branch is led out from the front end of the second throttle valve, a cold charging solenoid valve is provided on the branch, and the outlet of the branch merges with the outlet pipe of the second evaporator.

[0005] The cold storage plate is provided with a cold storage container, the first evaporator and the first heat exchanger are tubular heat exchangers and are arranged in the cold storage container to exchange heat with the cold storage liquid respectively.

[0006] The phase change temperature of the coolant in the cool release circuit is lower than the phase change temperature of the cool storage liquid on the cool storage plate.

[0007] Preferably, the second heat exchanger and the second evaporator are coil heat exchangers and are arranged on the inner wall of the compartment of the refrigerated truck.

[0008] The refrigeration unit also includes a compressor, a condenser and a first throttling device arranged at the front end of the first evaporator.

[0009] The present invention also provides a control method for the above refrigeration system, comprising:

[0010] Step 1. According to the cabin temperature T 厢 With the set temperature T 设 According to the comparison result, the refrigeration system is selected to enter the fast refrigeration mode or the low-speed refrigeration mode;

[0011] Step 2. In the fast cooling mode, according to the set temperature T 设 and the coolant temperature T 蓄 The comparison results select the refrigeration unit for refrigeration or the cold storage plate and refrigeration unit for refrigeration; in the low-speed refrigeration program, according to the set temperature T 设 and the coolant temperature T 蓄 The comparison results show that the cold storage plate or the refrigeration unit can be used for cooling.

[0012] When the cabin temperature T 厢 Greater than the set temperature T 设 When the temperature of the vehicle compartment is T 厢 Less than or equal to the set temperature T 设 When the value of A is equal to the sum of the values ​​of A and B, the low-speed cooling mode is selected.

[0013] In the fast cooling mode, determine the set temperature T 设 Is it greater than the coolant temperature T 蓄 If yes, the cold storage plate and refrigeration unit will start cooling together; if no, the refrigeration unit will start cooling.

[0014] In low-speed cooling mode, determine the set temperature T 设 Is it greater than the coolant temperature T 蓄 If yes, the system will enter the cold storage plate cooling operation; if not, the system will enter the refrigeration unit cooling operation.

[0015] Preferably, when the cold storage plate and the refrigeration unit are used for joint refrigeration, the rotation speed of the circulation pump is controlled according to the interval in which the temperature T2 of the second heat exchanger is located.

[0016] Preferably, during the cold storage plate cooling operation, the rotation speed of the circulation pump is controlled according to the interval in which the temperature T2 of the second heat exchanger is located.

[0017] During the cooling operation of the refrigeration unit, or the cooling operation of the cold storage plate and the refrigeration unit, when the set temperature T 设 Greater than the cabin temperature T 厢 When the sum of the C value is reached, turn off the refrigeration unit and return to step 1.

[0018] The present invention also provides a refrigerated vehicle, which includes the above refrigeration system and operates using the control method of the above refrigeration system.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention organically combines the cold storage plate with the refrigeration unit and optimizes the cold storage plate's cold release method. The cold energy is transferred to the coolant through the cold storage liquid, and then the coolant is transferred to the heat exchanger in the car through the coolant. The heat exchange temperature can be controlled by controlling the flow rate of the coolant, thereby meeting the temperature requirements of the refrigerated truck for transporting different goods and improving the mileage of the refrigerated truck. When the cold storage liquid temperature is lower than the set temperature of the car, the cold storage plate is cooled through the cold release circuit. When the cold storage liquid temperature is higher than the set temperature of the car, the cold storage plate is used to increase the supercooling of the refrigerant, fully utilizing the cold energy of the cold storage plate, and effectively improving the efficiency of the refrigeration unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0022] Figure 1 The schematic diagram of the refrigeration system proposed by the present invention;

[0023] Figure 2 This is a flow chart of an embodiment of a control method for a refrigeration system provided by the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation to the present invention.

[0025] The core of the present invention is to combine the cold storage plate with the refrigeration unit to meet the wide temperature working conditions of the refrigerated truck and improve the cruising range of the refrigerated truck.

[0026] like Figure 1 As shown, the refrigeration system proposed by the present invention includes: a cold storage plate and a refrigeration unit, wherein the refrigeration unit includes a compressor 1, a condenser 2, a first expansion valve 3, a first evaporator 4, a second expansion valve 5 and a second evaporator 6 connected in sequence by pipelines. A cold storage container is provided on the cold storage plate 13, and the first evaporator 4 and the first heat exchanger 7 are arranged in the cold storage container to exchange heat with the cold storage liquid in the cold storage container respectively. The first heat exchanger 7, the second heat exchanger 8, the circulating pump 9 and the coolant constitute a cold release circuit. The phase change temperature of the coolant in the cold release circuit should be lower than the phase change temperature of the cold storage liquid in the cold storage plate to ensure the flow of the coolant in the cold release circuit. A branch 11 is led out from the front end of the second expansion valve 5, on which a cold charging solenoid valve 12 is provided, and the outlet of the branch merges with the outlet pipe of the second evaporator 6.

[0027] The cold storage container on the cold storage plate 13 can be a shell and tube heat exchanger, the shell is used as the cold storage container, the first evaporator 4 and the first heat exchanger 7 are tube heat exchangers and are placed in the shell, respectively exchanging heat with the cold storage liquid in the cold storage container. Preferably, the second evaporator 6 and the second heat exchanger 8 are coil heat exchangers and are arranged on the inner wall of the refrigerated truck.

[0028] The refrigeration system proposed by the present invention is composed of a refrigeration circuit 10 and a cold release circuit 20, and the refrigeration circuit and the cold release circuit are connected together through a cold storage plate. The refrigeration circuit is responsible for refrigeration and charging the cold storage plate with cold. By adjusting the speed of the circulating pump 9, the flow rate of the coolant can be controlled, and then the temperature of the second heat exchanger in the refrigerated vehicle can be controlled to be within a suitable temperature range. When the cold release circuit is not working, the cold capacity of the cold storage plate can be reasonably used to increase the supercooling degree of the refrigeration unit, thereby improving the efficiency of the refrigeration unit.

[0029] The refrigeration system proposed by the present invention adopts the following control method, including:

[0030] Step 1. According to the cabin temperature T 厢 With the set temperature T 设 According to the comparison result, the refrigeration system is selected to enter the fast refrigeration mode or the low-speed refrigeration mode;

[0031] Step 2. In the fast cooling mode, according to the set temperature T 设 and the coolant temperature T 蓄 The comparison results select the refrigeration unit for refrigeration or the cold storage plate and refrigeration unit for refrigeration; in the low-speed refrigeration program, according to the set temperature T 设 and the coolant temperature T 蓄 The comparison results show that the cold storage plate or the refrigeration unit can be used for cooling.

[0032] When the cabin temperature T 厢 Greater than the set temperature T 设 When the temperature of the vehicle compartment is T 厢 Less than or equal to the set temperature T 设 When the value of A is equal to the sum of the values ​​of A and B, the low-speed cooling mode is selected.

[0033] In the fast cooling mode, determine the set temperature T 设 Is it greater than the coolant temperature T 蓄 If the value is equal to the sum of the value of B, the cold storage plate and the refrigeration unit will operate together for cooling; if not, the refrigeration unit will operate alone for cooling.

[0034] When the cold storage plate and the refrigeration unit are used for joint cooling, the rotation speed of the circulation pump is controlled according to the temperature range of the second heat exchanger T2 disposed on the inner wall of the vehicle compartment.

[0035] In the low-speed cooling program, determine the set temperature T设 Is it greater than the coolant temperature T 蓄 If yes, the system will enter the cold storage plate cooling operation; if not, the system will enter the refrigeration unit cooling operation.

[0036] During the cold storage plate release and refrigeration unit cooling operation, or during the refrigeration unit cooling operation, when the set temperature is greater than the compartment temperature T 厢 When the sum of the C value is reached, turn off the refrigeration unit and return to step 1.

[0037] In the cold storage plate cold release operation, the speed of the circulation pump is controlled according to the interval where the temperature T2 of the second heat exchanger is located. The specific control method is the same as the control method of the circulation pump in rapid refrigeration.

[0038] Figure 2 1 is a flow chart of an embodiment of a control method for a refrigeration system provided by the present invention, which specifically includes the following steps:

[0039] 1. Cold charging: Before the vehicle is driven, the machine is turned on for cold charging. At this time, the first expansion valve 3 is opened, the cold charging solenoid valve 12 is opened, the second expansion valve 5 is closed, and the circulation pump 9 is closed;

[0040] 2. Refrigeration: Real-time detection of the temperature T in the refrigerated compartment 厢 , if T 厢 >T 设 +10℃, it indicates that the unit needs to be heated, and the refrigeration system is controlled to enter the fast cooling mode. 厢 ≤T 设 When the temperature is +10℃, the refrigeration system is controlled to enter low-speed refrigeration mode.

[0041] 3. After entering the low-speed cooling mode, determine T 设 Is it greater than T 蓄 + 5℃, if T 设 >T 蓄 + 5℃, the cold storage plate is used to directly provide cooling for the compartment. At this time, the cold storage plate is used to release the cold, the refrigeration unit is turned off, the circulating pump 9 is turned on, and then the temperature T2 of the second heat exchanger in the compartment is detected in real time, and the speed of the circulating pump 9 is controlled according to the range of the temperature T2:

[0042] When T2 ≥ T 设 At -5℃, reduce the speed of the circulation pump by 1% each time;

[0043] When T 设 -10℃<T2<T 设 At -5℃, maintain the speed of the circulation pump unchanged;

[0044] When T2≤T 设 At -10℃, increase the speed of the circulation pump by 1% each time.

[0045] If the detection T 设 ≤T 蓄 +5℃, the cold storage plate cannot provide cold for the car, and the refrigeration unit is used for cooling. The circulating pump 9 is turned off, the compressor 1 is turned on, the first expansion valve 3 is opened to the maximum (no throttling effect), the second expansion valve 5 is opened for adjustment, the cold charging solenoid valve 12 is closed, and the second evaporator 6 provides cold for the refrigerated car. At this time, it is necessary to judge T in real time. 设 Is it greater than T 厢 +3℃, if T 设 >T 厢 +3℃, return to step 1 and re-judge whether to enter the fast cooling mode or the low-speed cooling mode.

[0046] 4. After entering the fast cooling mode: detect T 设 Is it greater than T 蓄 +5℃, if T 设 >T 蓄 +5℃, the cold storage plate and refrigeration unit are used to provide cold for the compartment at the same time. At this time, the compressor 1 is turned on, the first expansion valve 3 is opened to the maximum (not throttling), the second expansion valve 5 is opened for adjustment, and the cold charging solenoid valve 12 is closed. The circulation pump 9 is adjusted in the following way:

[0047] When T2 ≥ T 设 At -5℃, reduce the speed of the circulation pump by 1% each time;

[0048] When T 设 -10℃<T2<T 设 At -5℃, maintain the speed of the circulation pump unchanged;

[0049] When T2≤T 设 At -10℃, increase the speed of the circulation pump by 1% each time.

[0050] If the detection T 设 ≤T 蓄 At +5℃, the cold storage plate cannot provide cold air for the car. At this time, the refrigeration unit is used for cooling, the circulating pump 9 is turned off, the compressor 1 is turned on, the first expansion valve 3 is opened to the maximum (without throttling effect), the second expansion valve 5 is opened for adjustment, and the cold charging solenoid valve 12 is closed.

[0051] In the fast cooling mode, it is necessary to judge T in real time 设 Is it greater than T 厢 +3℃, if T 设 >T 厢 +3℃, return to step 1 and re-judge whether to enter the fast cooling mode or the low-speed cooling mode.

[0052] In the above embodiment, the flow rate of the circulating pump can be adjusted in the range of 1-100%. The change of 1% of the circulating pump is an empirical value obtained from experiments and can be adjusted according to actual conditions. The change is large and the adjustment speed is fast, but the accuracy is poor, the change is small, the flow rate changes slowly, and the required adjustment time is long. The temperature detection cycle in the control method is usually 5s, which can be adjusted according to actual conditions. The temperatures of 5°C and 10°C in the control method are both empirical values ​​obtained from experiments and can be adjusted according to actual conditions. Two points are mainly considered: small temperature difference leads to low heat exchange efficiency, and large temperature difference easily freezes the goods.

[0053] The present invention organically combines the cold storage plate and the refrigeration unit and applies them to the temperature control of the refrigerated truck to achieve good technical effects and has the following characteristics:

[0054] 1. Through the heat exchange of the coolant, the cold storage plate can meet the requirements of wide temperature conditions without changing the cold storage liquid;

[0055] 2. The combination of cold storage plate and refrigeration unit increases the mileage of refrigerated trucks;

[0056] 3. By designing the cold release scheme of the cold storage plate, the cold storage plate can be used for low-temperature refrigeration, and the high temperature can be used for refrigerant supercooling, so as to make full use of the cold capacity inside the cold storage plate and improve the efficiency of the refrigeration unit.

[0057] The above description is only a specific implementation of the present invention. It should be pointed out that any modification, equivalent substitution and change made within the spirit and framework of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for a refrigeration system of a refrigerated vehicle, the refrigeration system comprising a cold storage plate and a refrigeration unit, the cold storage plate being provided with a first evaporator and a first heat exchanger, the first heat exchanger, a circulating pump and a second heat exchanger forming a cold release circuit through a coolant; the refrigeration system comprising a first evaporator and a second evaporator, a second throttle valve being provided between the two, a branch being led out from the front end of the second throttle valve, a cold charging solenoid valve being provided on the branch, the outlet of the branch being merged with the outlet pipe of the second evaporator; It is characterized in that The control method comprises: Step 1. According to the cabin temperature T 厢 With the set temperature T 设 According to the comparison result, the refrigeration system is selected to enter the fast refrigeration mode or the low-speed refrigeration mode; Step 2. In the fast cooling mode, according to the set temperature T 设 and the coolant temperature T 蓄 The comparison results select the refrigeration unit for refrigeration or the cold storage plate and refrigeration unit for refrigeration; in the low-speed refrigeration program, according to the set temperature T 设 and the coolant temperature T 蓄 The comparison results show that the cold storage plate or the refrigeration unit can be used for cooling.

2. The control method according to claim 1, characterized in that: The phase change temperature of the coolant in the cool release circuit is lower than the phase change temperature of the cool storage liquid in the cool storage plate.

3. The control method according to claim 1, characterized in that: When the cabin temperature T 厢 Greater than the set temperature T 设 When the temperature of the vehicle compartment is T 厢 Less than or equal to the set temperature T 设 When the value of A is equal to the sum of the values ​​of A and B, the low-speed cooling mode is selected.

4. The control method according to claim 3, characterized in that: In the fast cooling mode, determine the set temperature T 设 Is it greater than the coolant temperature T 蓄 If yes, the cold storage plate and refrigeration unit will start cooling together; if no, the refrigeration unit will start cooling.

5. The control method according to claim 3, characterized in that: In low-speed cooling mode, determine the set temperature T 设 Is it greater than the coolant temperature T 蓄 If yes, the system will enter the cold storage plate cooling operation; if not, the system will enter the refrigeration unit cooling operation.

6. The control method according to claim 4, characterized in that: When the cold storage plate and the refrigeration unit are used for joint refrigeration, the rotation speed of the circulation pump is controlled according to the interval in which the temperature T2 of the second heat exchanger is located.

7. The control method according to claim 5, characterized in that: In the cold storage plate cooling operation, the rotation speed of the circulation pump is controlled according to the interval in which the temperature T2 of the second heat exchanger is located.

8. The control method according to claim 4 or 5, characterized in that: During the cooling operation of the refrigeration unit, or during the cooling operation of the cold storage plate and the refrigeration unit, when the set temperature of the cabin is greater than the cabin temperature T 厢 When the sum of the C value is reached, turn off the refrigeration unit and return to step 1.

9. A refrigerated vehicle, characterized in that: The refrigeration system of the refrigerated truck is operated using the control method described in any one of claims 1-8.

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