Heat energy recovery system

A heat energy recovery system, comprising:

• an evaporator for performing heat exchange between supercharged air to be supplied to an engine and working medium to thereby evaporate the working medium;
• a superheater for performing heat exchange between the working medium flown from the evaporator and heating medium to thereby heat the working medium;
• an expander for expanding the working medium flown from the superheater;
• a power recovery device connected to the expander;
• a condenser for condensing the working medium flown from the expander;
• a pump for causing the working medium to flow from the condenser to the evaporator;
• and
• a controller including
• an engine load calculation section for calculating an engine load,
• a maximum rotation speed determination section for determining a maximum rotation speed which is a rotation speed of the pump obtained when a pinch temperature reaches a target pinch temperature, the pinch temperature being a value which is obtained by subtracting a saturation temperature of the working medium from a temperature of the supercharged air in the evaporator, the determination being based on a relational expression representing a relationship between the engine load and the maximum rotation speed, and an engine load calculated by the engine load calculation section, and
• a rotation speed regulation section for regulating the rotation speed of the pump in such a way as to allow the degree of superheat of the working medium flowing into the expander to be equal to or greater than a reference value, and to allow the rotation speed to be equal to or less than a maximum rotation speed determined by the maximum rotation speed determination section.