Waste Heat Recovery Device, Heat Supply System, and Operation Method for Waste Heat Recovery Device

A waste heat recovery device that recovers heat of a first heat medium and transfers that heat to a second heat medium, the waste heat recovery device comprising:

• a first heat medium side inlet where the first heat medium flows in;
• a first heat medium side outlet where the first heat medium flows out;
• a first heat medium flow path where the first heat medium flows from the first heat medium side inlet to the first heat medium side outlet;
• a first pump provided in the first heat medium flow path and causing the first heat medium to flow in the first heat medium flow path;
• a second heat medium side inlet where the second heat medium flows in;
• a second heat medium side outlet where the second heat medium flows out;
• a second heat medium flow path where the second heat medium flows from the second heat medium side inlet to the second heat medium side outlet;
• a heat exchanger that exchanges heat between the first heat medium that flows through the first heat medium flow path and the second heat medium that flows through the second heat medium flow path;
• an expansion tank provided in the first heat medium flow path;
• a bypass flow path that causes the first heat medium to flow so as to bypass the heat exchanger in the first heat medium flow path;
• and
• a mixer provided at a location where the bypass flow path and the first heat medium flow path merge together, the mixer configured to adjust a ratio of a flow rate of the first heat medium that flows through the bypass flow path and a flow rate of the first heat medium that flows through the heat exchanger, thereby mixing them such that the temperature of the first heat medium after merging approaches a predetermined temperature.