The requirement of tubular heat exchangers is tested preferably with range of engineered types, either straight tubes, U-tubes, or helical tubes arrangemet is used. The Custom design also could be asked , which will fulfill a special demands of working substances, working parameters and/or other specific aspects of operations.
The most appropriate design will always depends on efficiency of heat transfer, or heat transfer parameters, like features of flow, velocity, pressure drop, but also on the process and operational requirements of the application , i.e. requirement of location, dismantling and cleaning of the tube bundle, the range of operating points or unification types in the process plant.
An important question is the selection of material. The using of reasonable quality of steel, with good heat and surface treatment is important for the durability and service life of design. The selection of improper material, or acceptance of inadequately treated semi-finished or finished product, may ultimately cause economic losses ,not only due to necessity to replace damaged equipment , as well as forced shutdown of the production facilities.
At the design process, first, the compliance with customer's demands is verified with the range of standard types ( helical tubes , U-tube , 1- and 2-passes in the tube and/or in the mantle, eventually 4-passes ) . When the design permits, selected type can be optimized in order to keep the reasonable investment costs and to meet the operational and performance demands.