Evaporator Shell and Tube Heat
Exchanger for Rooftop Air Conditioning Unit
Dry evaporator for freon refrigeration system. In this evaporator,
the filling amount of the refrigerant liquid
is small, which is about 35% to 40% of the internal volume of the
pipe group, and the refrigerant does not
have a free liquid surface during the vaporization process. It is
widely used in refrigeration and air
conditioning, there is the replacement of full-liquid evaporator
development trend. According to the
arrangement of the tube in the shell can be divided into straight
tube and U-tube two.
Straight tube dry evaporator. Its structure and full-liquid
evaporator similar, the difference is in a number
of horizontal smooth copper tube with a number of blocks on the
reverse arrangement of the cut arc of the
circular baffle area, the more important is the work process is
completely different. In a dry evaporator, the
liquid of the refrigerant evaporates in the tube while the liquid
refrigerant (water or brine) is cooled outside
The liquid freon is decompressed by the throttle valve and enters
the tube from the lower end of the cap.
With the flow in the tube, the absorption tube of water or brine
heat, liquid freon gradually vaporized, the
steam from the top cover to take over the return to the compressor.
As long as the tube freon flow rate is
greater than a certain value, you can ensure that the smooth return
of lubricants compressor. Dry
evaporators are generally made of steel pipe, can use light pipe,
can also be used with longitudinal fins of
the finned tube. The use of light tube when the heat transfer
coefficient is small, the number of processes.
With the inner fin tube when the heat transfer coefficient is
large, the number of processes can be
reduced. However, the light pipe is easier and cheaper than the
inner finned tube. In particular, in recent
years, the heat pipe's heat transfer coefficient is close to the
heat transfer coefficient of the inner fin tube.