Refrigeration apparatus with liquid subcooler evaporator outlet refrigerant low superheat

Abstract

The utility model belongs to a kind of low superheat degree refrigeration device with liquid subcooler evaporator outlet refrigerant. The technical problem to be solved is: pump liquid supply needs to increase barrel pump unit, input cost is high, equipment size is big, filling quantity is more, direct expansion liquid supply liquid supply height is limited, suction superheat degree is high, which can reduce the utilization rate of heat exchange area of evaporator, and the system energy efficiency is low. The technical scheme points are: gas-liquid separator O is connected with pump, evaporator return gas-liquid separator L through pipeline, gas-liquid separator is provided with liquid level detection device, liquid level signal of liquid level detection device is connected with control element, and control element controls opening or shutdown of pump. It is suitable for refrigeration system.

Description

Technical Field

[0001] This utility model belongs to the field of refrigeration technology, specifically a refrigeration device with a liquid subcooler, an evaporator outlet, and low refrigerant superheat. Background Technology

[0002] In refrigeration systems, the commonly used liquid supply methods for evaporators are direct expansion liquid supply and pump liquid supply. Pump liquid supply systems require the addition of a tank pump unit, which pressurizes the refrigeration pump to supply liquid to the terminal evaporator at a higher position. This involves multiple-rate circulation, resulting in high initial costs, a large volume of low-pressure circulation tank, and a large system charge. Direct expansion liquid supply systems are simpler, but the liquid supply height is limited. To avoid liquid carryover during suction and damage to the compressor, the evaporator outlet typically has a superheat of 7-10°C. However, high superheat reduces the utilization rate of the evaporator's heat exchange area, leading to low system energy efficiency. Utility Model Content

[0003] The purpose of this invention is to propose a refrigeration device with a liquid subcooler and low refrigerant superheat at the evaporator outlet, in order to solve the problems existing in the background technology: pump-supply requires the addition of a tank pump unit, resulting in high investment costs, large equipment size, large charging volume, limited liquid supply height for direct expansion supply, high suction superheat which reduces the heat exchange area utilization rate of the evaporator, and low system energy efficiency. The technical solution adopted to solve this technical problem is as follows: The first solution is a refrigeration device with a liquid subcooler and a low refrigerant superheat at the evaporator outlet, characterized in that: the refrigeration cycle is as follows: the compressor discharge port is connected sequentially through pipelines to the condenser, receiver, economizer ports A and B, liquid subcooler ports F and G, expansion valve I, evaporator, and gas-liquid separator ports L and M, returning to the compressor suction port; port E in the pipeline is connected sequentially through pipelines to expansion valve II, economizer ports C and D, returning to the compressor makeup port; port J in the pipeline is connected sequentially through pipelines to expansion valve III, liquid subcooler ports H and I, returning to the gas-liquid separator port N; port O of the gas-liquid separator is connected through pipelines to the pump and evaporator, returning to the gas-liquid separator port L; the gas-liquid separator is equipped with a liquid level detection device, and the liquid level signal of the liquid level detection device is connected to a control element, which controls the pump to start or stop. The second option is a refrigeration device with a liquid subcooler and a low refrigerant superheat at the evaporator outlet, characterized in that the refrigeration cycle is as follows: the compressor discharge port is connected in sequence through pipelines to the condenser, receiver, economizer ports A and B, liquid subcooler ports F and G, expansion valve I, evaporator, and gas-liquid separator ports L and M, returning to the compressor suction port; port E in the pipeline is connected in sequence through pipelines to expansion valve II, economizer ports C and D, returning to the compressor makeup port; port J in the pipeline is connected in sequence through pipelines to expansion valve III, liquid subcooler ports H and I, returning to the gas-liquid separator port N; port O of the gas-liquid separator is connected in pipelines to the pump, expansion valve I, and evaporator, returning to the gas-liquid separator port L; the gas-liquid separator is equipped with a liquid level detection device, and the liquid level signal of the liquid level detection device is connected to a control element, which controls the pump to start or stop.

[0004] In both of the above-mentioned schemes, the first throttle valve is either a thermostatic expansion valve, an electronic expansion valve, or an electronic expansion valve equipped with a dryness sensor at the evaporator outlet. Port E in the pipeline is located either on the pipeline between port B of the economizer and port F of the liquid subcooler, on the economizer itself, or on the pipeline between the receiver and port A of the economizer. Port J in the pipeline is either on the pipeline between port G of the liquid subcooler and the first throttle valve, on the liquid subcooler itself, or on the pipeline between port B of the economizer and port F of the liquid subcooler. The economizer has port A as its liquid inlet, port B as its liquid outlet, port C as its liquid inlet on the evaporator side, and port D as its gas outlet on the evaporator side. The liquid subcooler has port F as its liquid inlet, port G as its liquid outlet, port H as its liquid inlet on the evaporator side, and port I as its gas outlet on the evaporator side. The gas-liquid separator has ports L, M, and N located in the gas phase region, and port O located in the liquid phase region.

[0005] The above two methods are used as follows: When the refrigeration system is running, by adjusting the opening of the throttle valve, the superheat of the refrigerant at the evaporator outlet is made to be 0.5-4°C. A small amount of liquid droplets will appear at the evaporator outlet. After entering the gas-liquid separator, the droplets fall into the liquid phase zone of the gas-liquid separator. The liquid level detection device of the gas-liquid separator detects the liquid level height in the gas-liquid separator in real time and transmits the signal to the control element. When the liquid level in the gas-liquid separator reaches the set high liquid level value, the control element sends an start signal to the pump. The pump starts and pumps the refrigerant liquid in the gas-liquid separator into the evaporator. After evaporating into refrigerant gas in the evaporator, it returns to the gas-liquid separator. At this time, the liquid level in the gas-liquid separator begins to decrease. When the liquid level reaches the set low liquid level value, the control element sends a stop signal to the pump. The pump stops. This cycle continues to control the liquid level in the gas-liquid separator within a reasonable range.

[0006] The beneficial effects of this utility model compared with the prior art are as follows: Firstly, the superheat at the evaporator outlet is 0.5–4°C, resulting in a small amount of liquid droplets at the evaporator outlet. These droplets enter the gas-liquid separator and fall into its liquid phase zone. The liquid level detection device in the gas-liquid separator detects the liquid level height and transmits the signal to the control element. The control element then controls the pump's start and stop, pumping the liquid from the gas-liquid separator into the evaporator, thus controlling the liquid level within a reasonable range. This ensures that the compressor suction is free of liquid carryover, guaranteeing the compressor's safe operation. Secondly, because the evaporator outlet carries a small amount of liquid droplets, the suction superheat is lower than that of a dry direct expansion liquid supply system, resulting in a lower evaporation... The system boasts high area utilization, high heat transfer efficiency, and a small configuration area, improving system energy efficiency while reducing system charge volume. Furthermore, compared to pump-supply systems, it eliminates the need for a large-volume low-pressure circulation tank, resulting in smaller equipment size, lower system investment costs, and less charge volume. Additionally, the liquid exiting the economizer is further subcooled by a liquid subcooler, achieving an even lower degree of subcooling. This solves the problem of lower supply height compared to pump-supply systems, ensuring safe and reliable system operation. Moreover, when used in conjunction with an electronic expansion valve equipped with a dryness sensor at the evaporator outlet, the throttling valve precisely controls the liquid volume at the evaporator outlet, achieving near-zero superheat and further enhancing system efficiency. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of Embodiment 1 of the present utility model. Figure 2 This is a schematic diagram of Embodiment 2 of the present invention. Detailed Implementation

[0008] Example 1: Reference Figure 1 A refrigeration device with a liquid subcooler and a low refrigerant superheat at the evaporator outlet, characterized in that: the refrigeration cycle is as follows: the compressor 1 discharge port is connected in sequence through pipelines to the condenser 2, the receiver 3, the economizer 4A and B ports, the liquid subcooler 6F and G ports, the expansion valve 8, the evaporator 9, and the gas-liquid separator 13L and M ports, returning to the compressor 1 suction port; the pipeline E port is connected in sequence through pipelines to the expansion valve 5, the economizer 4C and D ports, returning to the compressor 1 makeup port; the pipeline J port is connected in sequence through pipelines to the expansion valve 7, the liquid subcooler 6H and I ports, returning to the gas-liquid separator 13N port; the gas-liquid separator 13O port is connected through pipelines to the pump 10 and the evaporator 9, returning to the gas-liquid separator 13L port; the gas-liquid separator 13 is equipped with a liquid level detection device 12, the liquid level signal of the liquid level detection device 12 is connected to the control element 11, and the control element 11 controls the opening or closing of the pump 10; the expansion valve 8 is a thermostatic expansion valve.

[0009] The above-mentioned method of using a refrigeration device with a liquid subcooler and low refrigerant superheat at the evaporator outlet is characterized in that: during the operation of the refrigeration system, by adjusting the opening of the throttle valve 8, the superheat of the refrigerant at the outlet of the evaporator 9 is made to be 0.5-4°C. A small amount of liquid droplets will appear at the outlet of the evaporator 9. After entering the gas-liquid separator 13, the droplets fall into the liquid phase zone of the gas-liquid separator 13. The liquid level detection device 12 of the gas-liquid separator 13 detects the liquid level height in the gas-liquid separator 13 in real time and transmits the signal to the control element 11. When the liquid level in the separator 13 reaches the set high liquid level value, the control element 11 sends an start signal to the pump 10, and the pump 10 starts, pumping the refrigerant liquid in the gas-liquid separator 13 into the evaporator 9. After evaporating into refrigerant gas in the evaporator 9, it returns to the gas-liquid separator 13. At this time, the liquid level in the gas-liquid separator 13 begins to decrease. When the liquid level reaches the set low liquid level value, the control element 11 sends a stop signal to the pump 10, and the pump 10 stops. This cycle continues, controlling the liquid level in the gas-liquid separator 13 within a reasonable range.

[0010] Example 2: Reference Figure 2 A refrigeration device with a liquid subcooler and a low refrigerant superheat at the evaporator outlet, characterized in that: the refrigeration cycle is as follows: the compressor 1 discharge port is connected in sequence through pipelines to condenser 2, receiver 3, economizer 4A and B ports, liquid subcooler 6F and G ports, expansion valve 8, evaporator 9, gas-liquid separator 13L and M ports, returning to the compressor 1 suction port; port E in the pipeline is connected in sequence through pipelines to expansion valve 5, economizer 4C and D ports, returning to the compressor 1 makeup port; port J in the pipeline... The gas-liquid separator 13N port is returned to the gas-liquid separator 13 via pipelines connected in sequence to throttle valve 7, liquid subcooler 6H port and I port; the gas-liquid separator 13O port is connected to pump 10, throttle valve 8, evaporator 9 via pipelines and returned to gas-liquid separator 13L port. The gas-liquid separator 13 is equipped with a liquid level detection device 12. The liquid level signal of the liquid level detection device 12 is connected to the control element 11, and the control element 11 controls the opening or closing of pump 10; throttle valve 8 is an electronic expansion valve with a dryness sensor at the outlet of evaporator 9.

[0011] The above-mentioned method of using a refrigeration device with a liquid subcooler and low refrigerant superheat at the evaporator outlet is characterized in that: during the operation of the refrigeration system, by adjusting the opening of the throttle valve 8, the superheat of the refrigerant at the outlet of the evaporator 9 is made to be 0.5-4°C. A small amount of liquid droplets will appear at the outlet of the evaporator 9. After entering the gas-liquid separator 13, the droplets fall into the liquid phase zone of the gas-liquid separator 13. The liquid level detection device 12 of the gas-liquid separator 13 detects the liquid level height in the gas-liquid separator 13 in real time and transmits the signal to the control element 11. When the liquid level in the separator 13 reaches the set high liquid level value, the control element 11 sends an start signal to the pump 10, and the pump 10 starts, pumping the refrigerant liquid in the gas-liquid separator 13 into the evaporator 9. After evaporating into refrigerant gas in the evaporator 9, it returns to the gas-liquid separator 13. At this time, the liquid level in the gas-liquid separator 13 begins to decrease. When the liquid level reaches the set low liquid level value, the control element 11 sends a stop signal to the pump 10, and the pump 10 stops. This cycle continues, controlling the liquid level in the gas-liquid separator 13 within a reasonable range.

Claims

1. A refrigeration device with a liquid subcooler and a low superheat of refrigerant at the evaporator outlet, characterized in that: The refrigeration cycle is as follows: The compressor (1) discharge port is connected in sequence through the pipeline to the condenser (2), the liquid receiver (3), the economizer (4) A port and B port, the liquid subcooler (6) F port and G port, the expansion valve (8), the evaporator (9), the gas-liquid separator (13) L port and M port, and returns to the compressor (1) suction port. The E port in the pipeline is connected in sequence through the pipeline to the expansion valve (5), the economizer (4) C port and D port, and returns to the compressor (1) make-up port. The J port in the pipeline is connected to the compressor (1) make-up port. The gas-liquid separator (13) is connected to the throttle valve (7), the liquid subcooler (6) H port and I port through the pipeline and returned to the gas-liquid separator (13) N port; the gas-liquid separator (13) O port is connected to the pump (10) and the evaporator (9) through the pipeline and returned to the gas-liquid separator (13) L port. The gas-liquid separator (13) is equipped with a liquid level detection device (12). The liquid level signal of the liquid level detection device (12) is connected to the control element (11). The control element (11) controls the pump (10) to start or stop.

2. A refrigeration device with a liquid subcooler and a low superheat of refrigerant at the evaporator outlet, characterized in that: The refrigeration cycle is as follows: The compressor (1) discharge port is connected in sequence through the pipeline to the condenser (2), the liquid receiver (3), the economizer (4) A port and B port, the liquid subcooler (6) F port and G port, the expansion valve (8), the evaporator (9), the gas-liquid separator (13) L port and M port, and returns to the compressor (1) suction port. In the pipeline, the E port is connected in sequence through the pipeline to the expansion valve (5), the economizer (4) C port and D port, and returns to the compressor (1) make-up port. In the pipeline, the J port is connected in sequence through the pipeline. The throttle valve (7), liquid subcooler (6) H port and I port are connected in sequence and returned to the gas-liquid separator (13) N port; the gas-liquid separator (13) O port is connected to the pump (10), throttle valve (8), evaporator (9) through the pipeline and returned to the gas-liquid separator (13) L port. The gas-liquid separator (13) is equipped with a liquid level detection device (12). The liquid level signal of the liquid level detection device (12) is connected to the control element (11). The control element (11) controls the pump (10) to start or stop.

3. A refrigeration device with a liquid subcooler and low refrigerant superheat at the evaporator outlet, as described in claim 1 or 2, characterized in that: The throttle valve (8) is either a thermal expansion valve, an electronic expansion valve, or an electronic expansion valve with a dryness sensor at the outlet of the evaporator (9).

4. A refrigeration device with a liquid subcooler and low refrigerant superheat at the evaporator outlet, as described in claim 1 or 2, characterized in that: The pipeline can be located at port E, or on the pipeline between port B of the economizer (4) and port F of the liquid subcooler (6), or on the economizer (4), or on the pipeline between the reservoir (3) and port A of the economizer (4).

5. A refrigeration device with a liquid subcooler and low refrigerant superheat at the evaporator outlet, as described in claim 1 or 2, characterized in that: The pipeline is located at port J, or on the pipeline between port G of the liquid subcooler (6) and throttle valve (8), or on the liquid subcooler (6), or on the pipeline between port B of the economizer (4) and port F of the liquid subcooler (6).

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