In case of direct flow schemethe medium move in one direction. Otherwise, heating and heated mediummove towards each other. Cross-flow direction is provided by the design of the heat exchanger: the mediummove perpendicularly and heat transfer occurs when they cross in the module of the apparatus.
The counter flow scheme is more efficient than the direct flow, cross-flow option also provides better heat transfer than in case of medium moving in one direction.
How to install a heat exchanger
The installation of a heat exchanger depends on its purpose and the type of medium used. The installation of a high-temperature heat exchanger in metallurgy has its own features; it serves to heat the primary air that is fed into the furnace to increase furnace performance. Exhaust hot gases from the furnace are used as the heating medium.
Installation of a heat exchanger may not differ from the installation method described earlier in case when the incoming heated medium is diverted from the unit to the equipment in which these processes take place. In some cases, the heat exchanger is directly built into the process line.
Heat exchanger efficiency calculations
Efficiency evaluation of the installed heat exchanger is carried out on the basis of thermal efficiency. The efficiency of the unit is calculated as the ratio of the amount of heat actually transferred between two medium to the theoretically possible maximum heat transfer. Thermal efficiency does not take into account the hydraulic resistance of the unit and the loss of quality of the transmitted heat. For more accurate calculations for further manufacture and subsequent verification of the heat exchanger efficiency, it is advisable to use the services of expert engineers.