Refrigeration apparatus suitable for low superheat of refrigerant at evaporator outlet
By optimizing the refrigeration cycle pipeline and using a gas-liquid separator and liquid level detection device to control the refrigerant superheat at the evaporator outlet, the problems of high equipment cost, large size and low energy efficiency in the existing technology are solved, and a highly efficient and safe refrigeration effect is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YANTAI AOWEI REFRIGERATION EQUIP CO LTD
- Filing Date
- 2025-08-15
- Publication Date
- 2026-07-21
AI Technical Summary
In existing refrigeration systems, pump-supply requires the addition of a tank pump unit, which results in high investment costs and large equipment size. Direct expansion has limited supply height, and high superheat at the evaporator outlet leads to low utilization of the heat exchange area and low system energy efficiency.
By adjusting the refrigeration cycle piping, combined with the gas-liquid separator and liquid level detection device, the pump is controlled to start and stop, ensuring that the refrigerant superheat at the evaporator outlet is between 0.5 and 4°C. The liquid is further subcooled by the subcooling heat exchanger in the gas-liquid separator, and the liquid carryover at the evaporator outlet is precisely controlled by an electronic expansion valve.
It achieves effective control of evaporator outlet superheat, improves heat exchange area utilization, reduces system charge and equipment volume, improves system energy efficiency, and ensures safe compressor operation.
Smart Images
Figure CN224534520U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of refrigeration technology, specifically a refrigeration device suitable for evaporator outlet refrigerant with low 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 suitable for low superheat of refrigerant at 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 direct expansion supply height, 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 suitable for evaporator outlet refrigerant with low superheat, 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, gas-liquid separator ports F and G, expansion valve I, evaporator, 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 replenishment port; port O of the gas-liquid separator is connected through pipelines to the pump, evaporator, returning to port L of the gas-liquid separator; 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: A refrigeration device suitable for low superheat of refrigerant at 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, gas-liquid separator ports F and G, expansion valve I, evaporator, gas-liquid separator ports L and M, and returns 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, and returns to the compressor replenishment port; port O of the gas-liquid separator is connected in pipelines to the pump, expansion valve I, and evaporator, and returns to port L of the gas-liquid separator; 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 the control element, which controls the pump to start or stop.
[0004] In the two schemes described above, the refrigeration device suitable for low refrigerant superheat at the evaporator outlet uses a throttling valve, a thermostatic expansion valve, an electronic expansion valve, or an electronic expansion valve with a dryness sensor at the evaporator outlet. The refrigeration device suitable for low refrigerant superheat at the evaporator outlet uses port E in the piping, either on the line between port B of the economizer and port F of the gas-liquid separator, on the economizer itself, or on the line between the receiver and port A of the economizer. Port A of the economizer is the liquid inlet, port B is the liquid outlet, port C is the liquid inlet on the evaporator side, and port D is the gas outlet on the evaporator side. Ports L and M of the gas-liquid separator are located in the gas phase region, port O is located in the liquid phase region, port F is the liquid inlet of the subcooled heat exchanger located below the gas-liquid separator, and port G is the liquid outlet of the subcooled heat exchanger located below the gas-liquid separator.
[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 evaporator surface temperature. It boasts high volumetric 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 subcooling heat exchanger within the gas-liquid separator, achieving an even lower degree of subcooling. This solves the problem of the direct expansion liquid supply height being lower than that of the pump supply, ensuring safe and reliable system operation. Moreover, when the throttling valve is used in conjunction with an electronic expansion valve equipped with a dryness sensor at the evaporator outlet, it can precisely control the liquid carryover at the evaporator outlet, achieving near-zero superheat and further increasing system efficiency. Attached Figure Description
[0007] Figure 1 This is a schematic diagram of the first embodiment of this utility model. Figure 2 This is a schematic diagram of the second embodiment of this utility model. Detailed Implementation
[0008] Example 1: Reference Figure 1 A refrigeration device suitable for evaporator outlet refrigerant with low superheat, characterized in that: the refrigeration cycle is as follows: the compressor 1 discharge port is connected in sequence through pipelines to condenser 2, liquid receiver 3, economizer 4A and B ports, gas-liquid separator 6F and G ports, expansion valve 8, evaporator 9, gas-liquid separator 6L and M ports and returns to compressor 1 suction port; port E in the pipeline is connected in sequence through pipelines to expansion valve 5, economizer 4C and D ports and returns to compressor 1 make-up gas port; gas-liquid separator 6O port is connected through pipelines to pump 10, evaporator 9 and returns to gas-liquid separator 6L port; gas-liquid separator 6 is equipped with liquid level detection device 7, the liquid level signal of liquid level detection device 7 is connected to control element 11, control element 11 controls the opening or closing of pump 10; expansion valve 8 is a thermostatic expansion valve.
[0009] The above-mentioned method of using a refrigeration device suitable for evaporator outlet refrigerant with low superheat 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 6, the droplets fall into the liquid phase zone of the gas-liquid separator 6. The liquid level detection device 7 of the gas-liquid separator 6 detects the liquid level height in the gas-liquid separator 6 in real time and transmits the signal to the control element 11. When the liquid level in the gas-liquid separator 6 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 6 into the evaporator 9. After evaporating into refrigerant gas in the evaporator 9, the gas returns to the gas-liquid separator 6, and the liquid level in the gas-liquid separator 6 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 6 within a reasonable range.
[0010] Example 2: Reference Figure 2 A refrigeration device suitable for evaporator outlet refrigerant with low superheat, characterized in that: the refrigeration cycle is as follows: the compressor 1 discharge port is connected in sequence through pipelines to condenser 2, liquid receiver 3, economizer 4A and B ports, gas-liquid separator 6F and G ports, expansion valve 8, evaporator 9, gas-liquid separator 6L and M ports and returns to compressor 1 suction port; the pipeline E port is connected in sequence through pipelines to expansion valve 5, economizer 4C and D ports and returns to compressor 1 replenishment port; the gas-liquid separator 6O port is connected in pipelines to pump 10, expansion valve 8, evaporator 9 and returns to gas-liquid separator 6L port; the gas-liquid separator 6 is equipped with a liquid level detection device 7, the liquid level signal of the liquid level detection device 7 is connected to control element 11, and control element 11 controls the start or stop of pump 10.
[0011] The above-mentioned method of using a refrigeration device suitable for evaporator outlet refrigerant with low superheat 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 6, the droplets fall into the liquid phase zone of the gas-liquid separator 6. The liquid level detection device 7 of the gas-liquid separator 6 detects the liquid level height in the gas-liquid separator 6 in real time and transmits the signal to the control element 11. When the liquid level in the gas-liquid separator 6 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 6 into the evaporator 9. After evaporating into refrigerant gas in the evaporator 9, the gas returns to the gas-liquid separator 6, and the liquid level in the gas-liquid separator 6 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 6 within a reasonable range.
Claims
1. A refrigeration apparatus adapted for low superheat of evaporator outlet refrigerant, characterized by: The refrigeration cycle is: the exhaust port of the compressor (1) is connected with the condenser (2), the liquid accumulator (3), the economizer (4) A port and B port, the gas-liquid separator (6) F port and G port, the throttle valve one (8), the evaporator (9), the gas-liquid separator (6) L port and M port in sequence through pipelines, and returns to the suction port of the compressor (1), the E port in the pipeline is connected with the throttle valve two (5), the economizer (4) C port and D port in sequence through pipelines, and returns to the gas supplement port of the compressor (1); the O port of the gas-liquid separator (6) is connected with the pump (10) and the evaporator (9) through pipelines and returns to the L port of the gas-liquid separator (6), the gas-liquid separator (6) is provided with the liquid level detection device (7), the liquid level signal of the liquid level detection device (7) is connected with the control element (11), and the control element (11) controls the opening or shutdown of the pump (10).
2. A refrigeration apparatus suitable for low superheat of evaporator outlet refrigerant, characterized by: The refrigeration cycle is: the exhaust port of the compressor (1) is connected with the condenser (2), the liquid accumulator (3), the economizer (4) A port and B port, the gas-liquid separator (6) F port and G port, the throttle valve one (8), the evaporator (9), the gas-liquid separator (6) L port and M port in sequence through pipelines, and returns to the suction port of the compressor (1), the E port is connected with the throttle valve two (5), the economizer (4) C port and the D port in sequence through pipelines, and returns to the gas supplement port of the compressor (1).
3. A refrigeration device suitable for low superheat of refrigerant at evaporator outlet according to claim 1 or 2, characterized in that: The throttle valve one (8) is a thermal expansion valve, an electronic expansion valve or an electronic expansion valve matched with a dryness sensor at the outlet of the evaporator (9).
4. The apparatus of claim 1 or 2 wherein: the evaporator is a flooded evaporator. The E port in the pipeline is connected with the economizer (4) B port and the gas-liquid separator (6) F port, or is connected with the economizer (4), or is connected with the liquid accumulator (3) and the economizer (4) A port.