Siphonic water-cooled screw low-temperature solution unit

Abstract

The invention discloses a siphonic water-cooled screw low-temperature solution unit, which comprises a screw compressor, a built-in oil condenser, a gas-liquid separator circulation tank and a siphonic evaporator; a gas outlet of the gas-liquid separator circulation tank communicates with a gas inlet of the screw compressor through a suction pipeline; the gas-liquid separator circulation tank and a delivery valve of the built-in oil condenser communicate with the suction pipeline through an oil return system; a liquid outlet of the built-in oil condenser separately communicates with the gas-liquid separator circulation tank and the siphonic evaporator through a liquid supply system; and the liquid supply system comprises a plurality of sections of liquid supply pipelines, an oil return heat exchanger and an economizer. According to the siphonic water-cooled screw low-temperature solution unit disclosed by the invention, by installing the oil return heat exchanger and the economizer, oil return temperature of the evaporator is increased, and oil return viscosity is reduced, so that oil return of the evaporator is more smooth; meanwhile, liquid refrigerant coming out from the condenser is lowered in temperature to realize a certain supercooling degree, therefore operating efficiency of the unit is increased.

Description

technical field [0001] The invention belongs to the field of refrigeration, and in particular relates to a siphon-type water-cooled screw low-temperature solution unit. Background technique [0002] At present, in the field of refrigeration, a kind of refrigeration unit with brine (NaCl or CaCl2) or ethylene glycol solution as the refrigerant and a screw compressor is commonly used in low-temperature freezing occasions, and the heat exchanger adopts a dry shell-and-tube evaporator This type of unit with water-cooled shell-and-tube condenser is generally called a dry-type water-cooled screw low-temperature brine (ethylene glycol) solution unit. Since the refrigeration system using the dry shell-and-tube evaporator relies on the evaporator itself to return air and carry oil, there is no oil in the evaporator, and no additional oil return system is required, so the system design and control are simple. However, the heat exchange of the dry evaporator is boiling heat exchange i...

AI Technical Summary

Problems solved by technology

The lower the temperature, the greater the mass concentration and kinematic viscosity of the brine, so that the Reynolds number Re of the brine fluid decreases significantly, the flow resistance increases, and the flow boundary layer and thermal boundary layer thicken, making the brine single-phase flow The heat transfer coefficient is greatly reduced, so that the heat transfer efficiency of the entire heat exchanger is greatly reduced

In order to improve the heat transfer effect of the refrigerant, two methods are generally adopted: one is to increase the flow rate of the refrigerant fluid, that is, to increase the flow rate to enhance heat transfer; the other is to increase the heat transfer rate of the heat exchanger. Thermal area; the former will inevitably increase the flow resistance of the fluid and increase the power consumption of the fluid-driven equipment, that is, the pump. The latter is to compensate for the decline in heat transfer efficiency at the cost of increasing the cost of equipment manufacturing. Obviously, these two methods are very uneconomical

The existing dry-type water-cooled screw low-temperature brine (ethylene glycol) solution units using conventional dry-type evaporators still have some problems in low-temperature conditions. For example, bow-shaped baffles are generally used in dry-type evaporators, and the brine The flow state at different positions between the baffles is extremely uneven, and there is a flow dead zone, and there is a gap between the baffles and the inner wall of the shell, resulting in a large bypass volume of the brine fluid, especially for high-concentration and high-viscosity fluids. The fluid is especially obvious, which greatly reduces the heat exchange efficiency of the heat exchanger

[0005] Therefore, for the water-cooled screw low-temperature brine / ethylene glycol solution unit, under the urgent requirement of continuously improving energy efficiency, there are certain technical problems and difficulties regardless of the use of dry or flooded evaporators. How to improve the water-cooled screw low-temperature brine / ethylene glycol solution unit? The efficiency of ethylene glycol solution units is a technical problem currently facing technicians

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