A still mill desires to cool 3000 gal/hr of an inorganic liquid from 250oF to 180oF by Lehigh River water flowing through a shell-and-tube exchanger at a rate of 5000 gal/hr. The liquid is somewhat acidic in nature and so an alloy exchanger is probably required. Within the plant is an unused S-and-T, floating-head exchanger have one shell pass and two tube passes. The shell is mild steel, and the tubes are type 304 stainless. Specifications of the surplus exchanger revel a 20-in I.D. shell with 158 1-in 14 BWG tubes 16 ft long laid out on a 1.25 in square pitch. Baffles are placed 6-in apart. Will the surplus exchanger be suitable for the cooling requirements? Assume the inorganic liquid has the physical properties of water.

The purpose of the regenerative heat exchanger is to essentially recycle the heat rejected in step (B) as heat absorbed in step (D). Show why this works for the case of a general working fluid with heat capacity, Cv(T). The Stirling engine (invented in 1816 by Robert Stirling) is a heat engine that produces work through cyclic compression and expansion of a gaseous working fluid, such as hot air. An idealized cyclic process, aptly named the Stirling Cycle, for such an engine consists of four steps: (A) isothermal expansion at the hot reservoir temperature, Th, (B) isochoric (constant volume) heat rejection to a regenerative heat exchanger, (C) isothermal compression at the cold reservioir temperature Te, and (D) isochoric heat absorption from the regenerative heat exchanger back to the initial state.