CO2 cooling device using a dryness sensor

Abstract

This utility model relates to a CO2 cooling device employing a dryness sensor. The technical problem it addresses is that flooded or siphon-type condenser-evaporator systems require large refrigerant charges, resulting in excessively high overall equipment costs; dry condenser-evaporator systems suffer from large heat exchange temperature differences and low system efficiency due to high suction superheat. The key technical points are: high-pressure liquid refrigerant from the condenser of the refrigeration system passes through pipelines sequentially via ports A and B of the gas-liquid separator, a throttling valve, ports E and F of the dry condenser-evaporator, a dryness sensor, and ports C and D of the gas-liquid separator before returning to the compressor suction port of the refrigeration system; ports G and H of the dry condenser-evaporator are connected to a CO2 low-pressure circulation tank via pipelines; the dryness sensor is connected to the dry condenser-evaporator to detect the liquid refrigerant content in its outlet pipe, and the dryness sensor is connected to a control element; the control element controls the opening of the throttling valve, ensuring that the superheat of the refrigerant gas in the outlet pipe of the dry condenser-evaporator is 0.5–4°C. This device is suitable for refrigeration systems.

Description

Technical Field

[0001] This utility model belongs to the field of refrigeration technology, specifically a CO2 cooling device using a dryness sensor. Background Technology

[0002] Existing conventional CO2 refrigeration systems typically employ shell-and-tube or plate-and-shell condensers / evaporators, installed above the low-pressure circulation tank. These condensers / evaporators generally use either flooded or siphon-type refrigerant supply methods. Both of these methods suffer from the problem of large refrigerant charge requirements. Furthermore, siphon-type condensers / evaporators have height requirements between the condenser and the gas-liquid separator, resulting in an overall taller system. While conventional dry direct expansion systems are simpler, the refrigerant gas at the outlet of a dry condenser / evaporator typically has a superheat of 7–10°C to ensure the compressor suction port is liquid-free and to prevent compressor damage. However, this suction superheat has a significant impact on system performance. Taking a cooling system with a CO2 circulation temperature of -25℃ and a condensation temperature of 35℃ as an example, when the system uses a flooded or siphon-type condenser-evaporator, the heat exchanger driving temperature difference is 3℃, the refrigerant evaporation temperature is -28℃, and the system COP is 2.35. When using a dry condenser-evaporator, in order to ensure that the refrigerant gas at the outlet of the condenser-evaporator has a superheat of 7℃, the heat exchanger driving temperature difference reaches 10℃, the refrigerant evaporation temperature is -35℃, and the system COP is only 1.77. Utility Model Content

[0003] The purpose of this invention is to propose a CO2 cooling device using a dryness sensor to solve the problems existing in the background technology: large refrigerant charge and high overall equipment height in flooded or siphon condenser-evaporator systems, and large heat exchange temperature difference and low system energy efficiency in dry condenser-evaporator systems due to high suction superheat. The technical solution adopted to solve this technical problem is: a CO2 cooling device using a dryness sensor, characterized in that: the refrigeration cycle is as follows: the high-pressure refrigerant liquid in the condenser of the refrigeration system passes through pipelines sequentially through ports A and B of the gas-liquid separator, a throttling valve, ports E and F of the dry condenser-evaporator, the dryness sensor, and ports C and D of the gas-liquid separator back to the suction port of the refrigeration system compressor; ports G and H of the dry condenser-evaporator are connected to a CO2 low-pressure circulation tank through pipelines; the dryness sensor is connected to the dry condenser-evaporator to detect the liquid refrigerant content in its outlet pipe, and the dryness sensor is connected to a control element; the control element controls the opening of the throttling valve so that the superheat of the refrigerant gas in the outlet pipe of the dry condenser-evaporator is 0.5-4°C. The dry condenser-evaporator can be a plate type, a shell-and-tube type, or a plate-and-shell type. The refrigerant can be either Freon or ammonia.

[0004] The C and D ports of the gas-liquid separator are located in the gas phase region. The A port of the gas-liquid separator is the liquid inlet of the heating coil located at the bottom of the gas-liquid separator, and the B port of the gas-liquid separator is the liquid outlet of the heating coil located at the bottom of the gas-liquid separator. The E port of the dry condenser-evaporator is the refrigerant liquid inlet, the F port of the dry condenser-evaporator is the refrigerant gas outlet, the G port of the dry condenser-evaporator is the gas inlet of the refrigerant CO2, and the H port of the dry condenser-evaporator is the liquid outlet of the refrigerant CO2. Attached Figure Description

[0005] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0006] Example: Reference Figure 1 A CO2 cooling device employing a dryness sensor is characterized in that: the refrigeration cycle is as follows: the high-pressure refrigerant liquid in the condenser of the refrigeration system passes through pipelines sequentially through ports A and B of the gas-liquid separator 1, throttle valve 3, ports E and F of the dry condenser-evaporator 5, dryness sensor 6, and ports C and D of the gas-liquid separator 1 back to the suction port of the refrigeration system compressor; ports G and H of the dry condenser-evaporator 5 are connected to the CO2 low-pressure circulation tank 4 through pipelines; the dryness sensor 6 is connected to the dry condenser-evaporator 5 to detect the liquid refrigerant content in its outlet pipe, and the dryness sensor 6 is connected to the control element 2; the control element 2 controls the opening of the throttle valve 3 so that the superheat of the refrigerant gas in the outlet pipe of the dry condenser-evaporator 5 is 0.5-4°C; the dry condenser-evaporator 5 is either a plate type, a shell-and-tube type, or a plate-and-shell type; the refrigerant is either Freon or ammonia.

Claims

1. A CO2 cooling device using a dryness sensor, characterized by: The refrigeration cycle is as follows: the high-pressure refrigerant liquid in the condenser of the refrigeration system passes through the pipeline sequentially through the gas-liquid separator (1) ports A and B, the throttle valve (3), the dry condenser evaporator (5) ports E and F, the dryness sensor (6), and the gas-liquid separator (1) ports C and D, returning to the suction port of the refrigeration system compressor; the dry condenser evaporator (5) ports G and H are connected to the CO2 low-pressure circulation tank (4) through the pipeline; the dryness sensor (6) is connected to the dry condenser evaporator (5) to detect the liquid refrigerant content in its outlet pipe, and the dryness sensor (6) is connected to the control element (2); the control element (2) controls the opening of the throttle valve (3) so that the superheat of the refrigerant gas in the outlet pipe of the dry condenser evaporator (5) is 0.5~4℃.

2. The CO2 cooling device using a dryness sensor according to claim 1, wherein: Dry condenser evaporator (5) can be plate type, shell and tube type, or plate and shell type.

3. The CO2 cooling device using a dryness sensor according to claim 1 or 2, characterized in that: The refrigerant is either Freon or ammonia.

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