Double Circuit Evaporator Shell and Tube

Heat Exchanger for Central Air Conditioning

Due to the internal and external fluid temperature is different, so the heat exchanger shell and tube

bundle temperature is also different. If the temperature difference between the two, the heat exchanger

will produce a lot of thermal stress, resulting in pipe bending, fracture, or from the tube board pull.

Therefore, when the tube and the shell temperature difference exceeds 50 ℃, the need to take

appropriate compensation measures to eliminate or reduce thermal stress. According to

the compensation measures adopted, shell and tube heat exchanger can be divided into the following

main types:

① fixed tube plate heat exchanger tube at both ends of the tube plate and the shell into one, simple

structure, but only for hot and cold fluid temperature difference is not, and the shell does not need

mechanical cleaning when the heat transfer operation. When the temperature difference is slightly larger

and the shell pressure is not too high, the elastic compensation ring can be installed on the housing to

reduce the thermal stress.

(2) The tube sheet at the end of the tube bundle of the floating head heat exchanger can float freely and

completely eliminate the thermal stress; and the whole tube bundle can be extracted from the casing for

easy mechanical cleaning and maintenance. Floating head heat exchanger is widely used, but the

structure is more complex, higher cost.

③ U-tube heat exchanger each tube are bent into U-shaped, both ends were fixed in the same tube board

upper and lower areas, with the help of the box within the partition into the import and export of two rooms.

This heat exchanger completely eliminates thermal stress, the structure is simpler than the floating head,

but the pipe is not easy to clean.

④ eddy current hot film heat exchanger vortex hot film heat exchanger using the latest vortex heat film

heat transfer technology, by changing the fluid movement state to increase the heat transfer effect, when

the media through the vortex tube surface, the strong erosion of the pipe surface, Thermal efficiency. Up

to 10000W / m2 ℃. At the same time this structure to achieve a corrosion-resistant, high temperature,

high pressure, anti-fouling function. Other types of heat exchanger fluid channel for the fixed direction of

the flow form, the formation of heat transfer tube surface flow, convective heat transfer coefficient

decreases.