Waste heat recovery device, waste heat recovery type ship propulsion device, and waste heat recovery method

摘要

PROBLEM TO BE SOLVED: To provide an exhaust heat recovery device capable of maintaining a heat quantity to be recovered, even when a temperature of cooling water discharged from an internal combustion engine is reduced, by heating the cooling water.SOLUTION: An exhaust heat recovery type vessel propulsion device 1 comprises: a diesel engine 3; a turbocharger 4; an air cooler 5; a cooling water flow passage 7 which circulates cooling water to cool the diesel engine; and an evaporator 21 which exchanges heat between the cooling water and working fluid. The cooling water flow passage 7 has: a passage 74 which introduces the cooling water discharged from the diesel engine 3 into the evaporator 21 without involving the air cooler 5; another passage 78 which introduces the cooling water discharged from the diesel engine 3 into the evaporator 21 through the air cooler 5; and a three-way valve 8 which adjusts a first flow rate of the cooling water introduced into the evaporator 21 through the passage 74 and a second flow rate of the cooling water introduced into the evaporator 21 through the other passage 78.