Analysis of an absorption machine driven by the heat recovery on an i.c. reciprocating engine

The present work studies an absorption machine driven by the heat recovery on an internal combustion (i.c.) reciprocating engine. The thermal energy recovered from the i.c. engine exhaust is used to drive a double-effect water–lithium bromide cycle, while the heat recovered from the cooling jacket of the engine drives a single-effect water–lithium bromide cycle. The two absorption cycles are integrated into a single unit with a common evaporator and absorber. The absorption unit was first evaluated by a cycle analysis determining the sensitivity to the main boundary conditions and to the internal parameters. Then a specific simulation code of all the different devices of the absorption machine was developed to evaluate the real performance and size of the unit together with its operating condition limits. The absorption machine shows a coefficient of performance around 1, very close to the performance of a traditional double-effect absorption chiller driven by steam or by a gas burner. The absorption unit could operate with cooling water inlet temperature lower than 35–368C and refrigerated outlet temperature higher than 38C.