Single-pass, direct-fired generator for an absorption chiller

A direct-fired generator for an absorption chiller includes an inner shell, in which combustion occurs, and an outer shell. The inner shell supports a tube bundle through which a first portion an absorption solution is conveyed. Combustion products makes a single pass across the tube bundle within the inner shell. Such construction minimizes the number of potential leak paths and facilitates leak testing of the generator at an intermediate stage of assembly. A flow distributor apportions solution flow to the tube bundle and to a second solution flow path which bypasses the tube bundle but which is likewise heated by the combustion occurring within the inner shell. The two solution flow paths converge after the solution flowing therethrough has been heated by the combustion occurring in the inner shell. A vapor separator disentrains solution in liquid form from vaporized solution before the vapor exits the generator.