Patent ID: 10358948

Abstract:
A thermal energy recovery device (1) includes a circulation passage (4) having an evaporator (10), an expander (14), a condenser (6), and pump (8), and a controller (18) controlling the rotational number of the pump (8). The expander (14) is driven upon introduction of a mixed medium of a working medium evaporated in the evaporator (10) and oil into the expander (14). The controller (18) can execute a thermal load control for controlling the rotational number of the pump (8) according to a thermal load in the evaporator (10) and an oil return control for driving the pump (8) at the rotational number higher than that of the pump (8) controlled by the thermal load control. The oil return control is executed if a preset oil accumulation condition regarding an accumulation degree of the oil that is separated from the working medium evaporated in the evaporator (10) is satisfied.