Industrial Applications

General process cooling is the largest and least glamorous industrial duty. Tower water or chilled water on one side, a process stream on the other, and fouling deciding how long it works. Tower water is open to atmosphere, biologically active and concentrating dissolved solids as it evaporates, so whatever the thermal calculation says, useful life is set by how well the fouling side can be cleaned.

Oil that runs above its working band thins, loses film strength, oxidises faster and attacks seals. Viscosity suppresses turbulence and thickens the boundary layer, which is why the OC range runs to larger shells and longer tube lengths than the general-purpose WU. Size against the cold end, where the oil is most viscous and the temperature difference is smallest at the same time.

Compression heats air and concentrates the moisture in it. An aftercooler drops the temperature so moisture condenses where a separator and trap can remove it. The aftercooler condenses that moisture but does not remove it, so a missing or failed separator delivers liquid water into the distribution system in slugs, which does more damage than uncooled air would have.

An engine wants its jacket water in a narrow band: hot enough to run efficiently, cool enough not to detonate or scale. A shell and tube exchanger holds that band while keeping the engine's treated coolant separate from whatever site water is available. Size on the worst credible summer site water temperature, because the engine cannot be cooled below that plus the exchanger approach.

Glycol buys freeze protection and costs performance. It is more viscous, less thermally conductive and lower in specific heat than water, and all three work against the duty at once. Set the concentration to the minimum the freeze protection genuinely requires: every point above that costs heat transfer and pumping power for the life of the system.

Pressure drop decides more selections than people expect. On oil it rises steeply with both flow and viscosity, and a unit selected on thermal duty alone can be impossible to pump through at the flow the system delivers. On compressed air every psi is compression energy already paid for, and paid for again every hour the compressor runs. State the allowable drop with the enquiry.

Industrial cooling water is frequently untreated and industrial process fluids leave deposits. On a U-tube bundle the cleanable side is the shell side, because nothing rigid passes a 180 degree bend, so the fouling fluid belongs there and the clean fluid belongs in the tubes. It is worth checking on an existing installation whose duty has changed over the years.

Both fluids named rather than described, because oil at ISO VG 46 behaves nothing like oil at VG 10. Flow rate, inlet and required outlet temperature on each side, and the allowable pressure drop on each side. The duty profile if it is not steady, and which stream fouls. Call and talk it through with an engineer: 1-805-484-2992