Thermal energy recovery device

Abstract

Provided is a thermal energy recovery device in which poor lubrication of a bearing can be inhibited when an expander is driven. The thermal energy recovery device includes an evaporator (10), an expander (20), a power recovery machine (30), a condenser (40), a pump (50), a circulation flow path (60), a cooling flow path (70) for supplying working fluid from the pump (50) partially to the power recovery machine (30), an on-off valve (V1) provided in the cooling flow path (70), and a control unit (80), in which the expander (20) has a rotor (21), a bearing (22), and a primary casing (23), and in which the power recovery machine (30) has a power recovery unit (31) and a secondary casing (35), and in which upon reception of a stop signal for stopping power recovery by the power recovery machine (30), the control unit (80) closes the on-off valve (V1).

Description

BACKGROUND OF THE INVENTIONField of the Invention[0001]The present invention relates to a thermal energy recovery device.Description of the Related Art[0002]There have conventionally been known thermal energy recovery devices for recovering power from exhaust heat from various types of equipment such as plants. For example, JP 2012-97725 discloses a generator system (thermal energy recovery device) including an evaporator, a closed generator, a condenser, a fluid supply pump, a circulation flow path connecting the evaporator, the closed generator, the condenser, and the fluid supply pump in this order, and a cooling tube. The evaporator evaporates working medium. The closed generator generates electric power from the expansion energy of working medium flowing out of the evaporator. Specifically, the closed generator has a screw turbine for expanding working medium, a generator connected to the screw turbine via an output shaft, and a housing case housing the screw turbine, the outpu...

AI Technical Summary

Benefits of technology

The present invention provides a thermal energy recovery device that can prevent poor lubrication of a bearing when an expander is driven.

Problems solved by technology

Such a thermal energy recovery device as described in JP 2012-97725 has a concern that the lubrication of the bearing of the screw turbine may be insufficient when the device restarts after stopping.

Specifically, when the thermal energy recovery device comes into a stop operation, the rotational speed of the pump starts decreasing.

When the accumulation of the working medium of liquid phase then causes the bearing of the screw turbine to be immersed in the working medium of liquid phase, there is a concern of poor lubrication of the bearing when the device restarts (when the screw turbine is driven).

Accordingly, the bearing of the expander is inhibited from being immersed in the working medium of liquid phase and thereby poor lubrication of the bearing is inhibited when the thermal energy recovery device restarts.

Also in the thermal energy recovery device above, poor lubrication of the bearing of the expander is inhibited when the device is driven (starts to operate).

In contrast, in the thermal energy recovery device, since the control unit is arranged to open the liquid draining valve after the pump is stopped, such a trouble as described above is inhibited.

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