ABSTRACT
Shell-and-tube heat exchangers are frequently employed to supply domestic hot water for large buildings such as hospitals, restaurants, schools, and office complexes. An optimal heat exchanger transfers heat from the source to the target material with minimal losses to the surrounding environment. The actual amount of heat transferred varies with the heat exchanger design, the specific applications desired, the physical limits as directed by thermal efficiency, and finally, with fouling (corrosion bi-product and/or scaling).
In order to combat the problems of corrosion and scale build-up, both industry, as well as the United States military, have investigated the possibility of coating domestic water heat exchanger bundles in order to mitigate heat transfer reductions and premature failures. The feasibility of this venture is constrained by the thermal insulating properties of candidate coating materials relative to the cost savings which they provide. In order to properly determine the overall efficacy of these materials as corrosion/scale inhibitors, an experimental apparatus has been designed, assembled, and calibrated in order to provide a controlled crossflow environment with respect to corrosivity (Langelier index), Reynolds number of the flow over a test cylinder, and isothermal wall temperature.
