The absorption power generator is similar to a steam power plant where water vapor is generated under pressure in a boiler and then expanded in a prime mover such as a steam turbine or a reciprocating expansion engine. All of the exhaust water vapor from the steam power plant prime mover is collapsed to liquid by condensation in a condenser and then pumped back to the boiler. The absorption power generator works similarly except that the temperature of the heating medium for the boiler can be much lower. This is because of a low boiling point liquid, such as ammonia, is used to make pressurized vapor instead of water. Instead of condensing the low pressure ammonia vapor from the prime mover in a condenser, it is absorbed by water containing spray in an absorber vessel. Unused heat is rejected from the process at ambient air temperatures in a high pressure condenser vessel connected to the boiler. In the absorption power generator, the boiler is replaced by a special vertical tube evaporator