Evaporator refrigerating capacity adjusting control system and method during series connection of multiple stages of evaporators

Abstract

The invention relates to the technical field of refrigerating capacity control methods, in particular to an evaporator refrigerating capacity adjusting control system and method during series connection of multiple stages of evaporators. The single-stage evaporator refrigerating system comprises a plurality of groups of single-stage evaporator refrigerating systems connected in series and an electromagnetic valve coil control system capable of independently controlling the single-stage evaporator refrigerating systems. The control circuit has the beneficial effects that according to the technical scheme, synchronous starting and stopping of the compressor and the electromagnetic valve coil are achieved through the simple circuit principle, so that reliable control over the refrigerating system is achieved, the circuit is arranged to control the electromagnetic valve coil on a refrigerating system pipeline to be powered on and powered off, the electromagnetic valve coil is powered on, and then the electromagnetic valve is opened; part of refrigerant passes through the bypass pipeline where the electromagnetic valve is located, the refrigeration output capacity of the system is reduced, and the refrigerating capacity of the system is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration capacity control methods, and in particular to an evaporator refrigeration capacity adjustment control system and method when multiple evaporators are connected in series. Background Art

[0002] In a fresh air refrigeration and air conditioning system or an evaporator refrigeration and dehumidification refrigeration system with a large dehumidification capacity, using only one evaporator as a cold source cannot meet the requirements of production or life when the load is heavy. Therefore, it is necessary to increase the number of evaporators and use multiple evaporators working in series to increase the cooling or dehumidification capacity of the system.

[0003] Prior art, application number: CN201410129511.3, a high-precision dynamic control method for the cooling capacity of a compressor refrigeration system, which can only control a single evaporator and cannot cooperate with multiple evaporators in series. When multiple evaporators work in series, if the system uses a variable frequency compressor, it will greatly increase the manufacturing cost, and the compressor cannot obtain the best energy efficiency ratio when the frequency is changed; if the system does not use a variable frequency compressor, when dealing with changes in air conditions, in order to achieve the purpose of accurately controlling temperature and humidity and saving energy, it is necessary to adjust the cooling capacity supply and demand balance of the evaporator.

[0004] Therefore, it is necessary to design an evaporator refrigeration capacity adjustment control system and method when multiple evaporators are connected in series to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a control system and method for regulating the evaporator refrigeration capacity when multiple evaporators are connected in series, so as to overcome the above-mentioned shortcomings of the current prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A control system and method for regulating evaporator refrigeration capacity when multiple evaporators are connected in series, comprising a mold base, a plurality of groups of single-stage evaporator refrigeration systems connected in series, and a solenoid valve coil control system capable of controlling the single-stage evaporator refrigeration systems individually;

[0008] The solenoid valve coil control system includes several groups of compressor AC contactors connected in series, and a positive circuit and a negative circuit. The positive circuit is divided into two paths connected in parallel to the normally open and normally closed contacts of the positive poles of the compressor AC contactors of the last group connected in series. The negative normally closed contacts of the compressor AC contactors of the last group are divided into two paths connected in parallel to the positive normally open and normally closed contacts of the previous group of AC contactors, so that several groups of compressor AC contactors are connected in series in a cycle; the negative normally open contacts of each group of compressor AC contactors are respectively connected to the outside with electromagnetic coils, and the external electromagnetic coils of each group of compressor AC contactors are connected in parallel to the negative circuit;

[0009] A solenoid valve coil control relay is also provided on the negative pole circuit, and the solenoid valve coil control relay is placed at the front end of the solenoid coil, and the solenoid valve coil control relay is used to control whether different solenoid valve coils are energized;

[0010] The number of the single-stage evaporator refrigeration systems is the same as the number of the compressor AC contactors, and they are connected to each other one by one in sequence.

[0011] Preferably, a specific solenoid valve coil control system is used to control the energization and de-energization of the hot gas bypass solenoid valve on the pipeline of the single-stage evaporator refrigeration system. When the solenoid valve coil is energized, the hot gas bypass solenoid valve opens, and part of the refrigerant passes through the bypass pipeline where the hot gas bypass solenoid valve is located, thereby reducing the system's refrigeration output capacity and reducing the system's cooling capacity.

[0012] Preferably, the single-stage evaporator refrigeration system comprises an evaporator, a compressor connected to the evaporator outlet through a pipeline, a condenser connected to the compressor outlet through a pipeline, a throttling device arranged on the pipeline connecting the evaporator inlet and the condenser, the condenser is connected to the inlet of the evaporator through a pipeline, and the pipeline connecting the condenser and the inlet of the evaporator is also externally connected to a plurality of groups of parallel external pipelines, and the other ends of the external pipelines are mutually connected to the pipeline connecting the compressor outlet and the condenser, and a hot gas bypass solenoid valve is arranged on each group of external pipelines, and the hot gas bypass solenoid valve is closed by the control of the electromagnetic coil;

[0013] The compressors in each group of single-machine evaporator refrigeration systems respectively correspond to a group of compressor AC contactors of a solenoid valve coil control system and are connected with each other by electrical signals.

[0014] Preferably, after power is applied to the normally open and normally closed contacts of the AC contactor, the electromagnetic induction phenomenon generated by the coil of the AC contactor causes the slider to close, so that the normally open contact is attracted to a closed state and the normally closed contact is opened to an open state.

[0015] The beneficial effects of the present invention are as follows: the technical solution realizes the synchronous start and stop of the compressor and the solenoid valve coil through a relatively simple circuit principle, thereby realizing reliable control of the refrigeration system. The circuit is set to control the power-on and power-off of the solenoid valve coil on the refrigeration system pipeline. When the solenoid valve coil is energized, the solenoid valve opens, and part of the refrigerant passes through the bypass pipeline where the solenoid valve is located, thereby reducing the refrigeration output capacity of the system and reducing the refrigeration capacity of the system. The accuracy of the control system's refrigeration capacity increases with the increase in the number of solenoid valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a wiring schematic diagram of a solenoid valve coil of an evaporator refrigeration capacity adjustment control system and method when multiple evaporators are connected in series according to the present invention;

[0017] Figure 2 A single-stage evaporator refrigeration system diagram of a control system and method for regulating evaporator refrigeration capacity when multiple-stage evaporators are connected in series according to the present invention;

[0018] In the figure: 1, 2, 3 - compressor AC contactor; 11, 12, 13 - solenoid valve coil; 4 - solenoid valve coil control relay; 5 - positive access line; 6 - negative access line;

[0019] 7, 17, 27——evaporator, 8, 18, 28——compressor, 9, 19, 29——condenser, 10, 20, 30——throttling device, 14, 24, 34——hot gas bypass solenoid valve. DETAILED DESCRIPTION

[0020] Reference Figure 1 to Figure 2 , a control system and method for regulating evaporator refrigeration capacity when multiple evaporators are connected in series, comprising a plurality of groups of single-stage evaporator refrigeration systems connected in series, and a solenoid valve coil control system capable of controlling the single-stage evaporator refrigeration systems individually;

[0021] The solenoid valve coil control system includes a plurality of sets of compressor AC contactors connected in series, as well as a positive circuit and a negative circuit;

[0022] The positive circuit is divided into two paths connected in parallel to the normally open and normally closed contacts of the positive pole of the last group of compressor AC contactors connected in series (the normally open and normally closed contacts of the AC contactor generate electromagnetic induction phenomena due to the coil of the AC contactor after power is turned on, so that the slider is attracted, so that the normally open position is attracted into a closed state, and the normally closed position is disconnected into an open state), and the negative normally closed contact of the last group of compressor AC contactors is divided into two paths connected in parallel to the positive normally open and normally closed contacts of the previous group of AC contactors, so that several groups of compressor AC contactors are connected in series in this cycle, and the negative normally open contacts of each group of compressor AC contactors are respectively connected to the outside with electromagnetic coils, and the external electromagnetic coils of each group of compressor AC contactors are connected in parallel to the negative circuit;

[0023] A solenoid valve coil control relay is also provided on the negative pole circuit, and the solenoid valve coil control relay is placed at the front end of the solenoid coil, and the solenoid valve coil control relay is used to control whether different solenoid valve coils are energized.

[0024] The number of the single-stage evaporator refrigeration system is the same as the number of the compressor AC contactors, and they are connected to each other one by one in sequence; the specific solenoid valve coil control system is used to control the power on and off of the hot gas bypass solenoid valve on the pipeline of the single-stage evaporator refrigeration system. When the solenoid valve coil is energized, the hot gas bypass solenoid valve is opened, and part of the refrigerant passes through the bypass pipeline where the hot gas bypass solenoid valve is located, thereby reducing the refrigeration output capacity of the system and reducing the refrigeration capacity of the system;

[0025] The single-stage evaporator refrigeration system includes an evaporator, a compressor connected to the evaporator outlet through a pipeline, a condenser connected to the compressor outlet through a pipeline, a throttling device arranged on the pipeline connecting the evaporator inlet and the condenser, and the condenser is connected to the inlet of the evaporator through a pipeline. At the same time, the pipeline connecting the condenser and the inlet of the evaporator is also externally connected to a plurality of groups of parallel external pipelines, and the other ends of the external pipelines are mutually connected to the pipelines connecting the compressor outlet and the condenser, and a hot gas bypass solenoid valve is arranged on each group of external pipelines, and the hot gas bypass solenoid valve is closed by the control of the solenoid coil; the compressors in each group of single-machine evaporator refrigeration systems correspond to a group of compressor AC contactors of the solenoid valve coil control system, which are mutually connected by electrical signals;

[0026] The cooling capacity is controlled by setting the number of external pipes and hot gas bypass solenoid valves. For example, the bypass volume of the first group of hot gas bypass solenoid valves is 1 / 2, and the bypass volume of the second group of hot gas bypass solenoid valves is 1 / 4. If only the second hot gas bypass solenoid valve is opened, the bypass volume is 1 / 4. If only the first hot gas bypass solenoid valve is opened, the bypass volume is 2 / 4. If both are opened at the same time, the bypass volume is 3 / 4. Taking this as an example, increase or decrease the number for precise adjustment.

[0027] This implementation case reference Figure 1 , 2 , is a three-stage evaporative cooling principle diagram, corresponding to Figure 1 The solenoid valve wiring schematic diagram in the figure corresponds one by one from left to right, taking a three-stage evaporator refrigeration system as an example (if the number of stages in the refrigeration system increases or decreases, the circuit needs to be increased or decreased accordingly). The three-stage evaporator corresponds to three AC contactors. According to the changes in the air intake conditions (left in and right out), the start and stop sequence of the compressors corresponding to the three evaporators is: open from left to right and close from right to left, that is, the refrigeration capacity of the compressor increases when it is opened from left to right, and the refrigeration capacity decreases when it is closed from right to left.

[0028] The specific connection method is as follows, 5 is the positive connection point of the circuit, 6 is the negative connection point of the circuit, and 5 and 6 together constitute a circuit loop. The positive line is divided into two paths and connected in parallel to the normally open and normally closed contacts of the positive pole of the AC contactor 3 (the normally open and normally closed contacts of the AC contactor will produce electromagnetic induction phenomena due to the AC contactor coil after power is turned on, so that the slider is attracted, so that the normally open part is attracted into a closed state, and the normally closed part is disconnected into an open state). The negative normally open contact of the AC contactor 3 is connected to the electromagnetic coil 13, and the negative normally closed contact of the AC contactor 3 is divided into two paths and connected in parallel to the positive normally open and normally closed contacts of the AC contactor 2; the negative normally open contact of the AC contactor 2 is connected to the electromagnetic coil 12; the normally closed contact of the negative pole of the AC contactor 2 is connected to the positive normally open contact of the AC contactor 1, and the negative normally open contact of the AC contactor 1 is connected to the electromagnetic coil 11, and the three solenoid valves are connected in parallel to the negative line; taking the example of installing a hot gas bypass solenoid valve at each stage of refrigeration in the system, the power line of the compressor 8 is connected to Figure 1 The power line of compressor 18 is connected to the left side of the AC contactor 1; Figure 1 The power line of compressor 28 is connected to the left side of the AC contactor 2; Figure 1 When each compressor is started, its corresponding AC contactor is energized, and the on and off of solenoid valves 14, 24, and 34 are controlled by Figure 1 The corresponding solenoid valve coils 11, 12, and 13 are determined by whether they are energized. If the solenoid valve coils are energized, the corresponding solenoid valves are opened;

[0029] The specific control methods include the following:

[0030] S1. When only compressor 8 is turned on, if the system refrigeration capacity needs to be reduced, compressors 18 and 28 are not working, the normally closed contacts of AC contactors 2 and 3 are in the on state, and the normally open contacts are disconnected, so the electromagnetic coils 12 and 13 are in the off state; but when compressor 8 is working, the normally open point of AC contactor 1 is powered on, the electromagnetic valve coil control relay K1 is energized, and the electromagnetic valve coil 11 is energized. The control system can control the switch of the hot gas bypass electromagnetic valve 14 of the first refrigeration system by controlling the switch of relay 4, thereby controlling the refrigeration output capacity of the first refrigeration system;

[0031] S2. Under the condition that compressors 8 and 18 are both turned on, if the system refrigeration capacity needs to be reduced, only the system of compressor 18 needs to be adjusted. In this state, compressors 8 and 18 are working, and the normally open contacts of compressor AC contactors 1 and 2 are energized to close and energize, and the normally closed contacts are energized to open; while compressor 28 is not working, and the normally open and normally closed contacts of compressor AC contactor 3 remain unchanged. At this time, the current can only pass through the normally closed contact of compressor AC contactor 3 and then through the closed normally open contact of compressor AC contactor 2 and then through the solenoid valve coil 12. The control system can control the switch of the hot gas bypass solenoid valve 24 of the second refrigeration system by controlling the switch of relay 4, thereby controlling the refrigeration output capacity of the second refrigeration system;

[0032] S3. When compressors 8, 18, and 28 are all turned on, if the system refrigeration capacity needs to be reduced, only the system of compressor 28 needs to be adjusted. In this state, compressors 8, 18, and 28 are all working. In this state, the normally open and normally closed contacts of the three AC contactors are all in action, and the current can only pass through the normally open contact of the compressor AC contactor 3 that has been closed and then through the solenoid valve coil 13. The control system can control the switch of the hot gas bypass solenoid valve 34 of the third refrigeration system by controlling the switch of the relay 4, thereby controlling the refrigeration output capacity of the third refrigeration system;

[0033] In the above circuit principle description, only the case where one refrigeration system is configured with one solenoid valve for regulation is listed. If the refrigeration system requires more precise regulation, the number of solenoid valves needs to be increased, and regulation can be performed by connecting multiple solenoid valves and multiple relays in parallel, but the control logic is the same as above.

[0034] The benefits of the present invention are that the technical solution realizes the synchronous start and stop of the compressor and the solenoid valve coil through a relatively simple circuit principle, thereby realizing reliable control of the refrigeration system. A circuit is set to control the power-on and power-off of the solenoid valve coil on the refrigeration system pipeline. When the solenoid valve coil is energized, the solenoid valve opens, and part of the refrigerant passes through the bypass pipeline where the solenoid valve is located, thereby reducing the refrigeration output capacity of the system and reducing the refrigeration capacity of the system. The accuracy of the control system's refrigeration capacity increases with the increase in the number of solenoid valves.

[0035] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A control system and method for regulating the evaporator refrigeration capacity when multiple evaporators are connected in series, characterized in that: It includes several groups of single-stage evaporator refrigeration systems connected in series, and a solenoid valve coil control system capable of controlling the single-stage evaporator refrigeration system individually; The solenoid valve coil control system includes several groups of compressor AC contactors connected in series, and a positive circuit and a negative circuit. The positive circuit is divided into two paths connected in parallel to the normally open and normally closed contacts of the positive poles of the compressor AC contactors of the last group connected in series. The negative normally closed contacts of the compressor AC contactors of the last group are divided into two paths connected in parallel to the positive normally open and normally closed contacts of the previous group of AC contactors, so that several groups of compressor AC contactors are connected in series in a cycle; the negative normally open contacts of each group of compressor AC contactors are respectively connected to the outside with electromagnetic coils, and the external electromagnetic coils of each group of compressor AC contactors are connected in parallel to the negative circuit; A solenoid valve coil control relay is also provided on the negative pole circuit, and the solenoid valve coil control relay is placed at the front end of the solenoid coil, and the solenoid valve coil control relay is used to control whether different solenoid valve coils are energized; The number of the single-stage evaporator refrigeration systems is the same as the number of the compressor AC contactors, and they are connected to each other one by one in sequence.

2. The evaporator refrigeration capacity adjustment control system and method when multiple evaporators are connected in series according to claim 1, characterized in that: The specific solenoid valve coil control system is used to control the energization and de-energization of the hot gas bypass solenoid valve on the pipeline of the single-stage evaporator refrigeration system. When the solenoid valve coil is energized, the hot gas bypass solenoid valve opens, and part of the refrigerant passes through the bypass pipeline where the hot gas bypass solenoid valve is located, reducing the system's refrigeration output capacity and reducing the system's cooling capacity.

3. The evaporator refrigeration capacity adjustment control system and method when multiple evaporators are connected in series according to claim 1, characterized in that: The single-stage evaporator refrigeration system includes an evaporator, a compressor connected to the evaporator outlet through a pipeline, a condenser connected to the compressor outlet through a pipeline, a throttling device arranged on the pipeline connecting the evaporator inlet and the condenser, and the condenser is connected to the inlet of the evaporator through a pipeline. At the same time, the pipeline connecting the condenser and the inlet of the evaporator is also externally connected to a plurality of groups of parallel external pipelines, and the other ends of the external pipelines are interconnected with the pipelines connecting the compressor outlet and the condenser, and a hot gas bypass solenoid valve is arranged on each group of external pipelines, and the hot gas bypass solenoid valve is closed by the control of the solenoid coil; the compressors in each group of single-machine evaporator refrigeration systems correspond to a group of compressor AC contactors of the solenoid valve coil control system, and the electrical signals are connected to each other.

4. The evaporator refrigeration capacity adjustment control system and method when multiple evaporators are connected in series according to claim 1, characterized in that: After power is applied to the normally open and normally closed contacts of the AC contactor, the electromagnetic induction phenomenon generated by the coil of the AC contactor causes the slider to close, so that the normally open contact is pulled into a closed state and the normally closed contact is pulled into an open state.

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