Heat recovery device and method

A method for operating a heat recovery device comprising:

• providing the heat recovery device, the heat recovery device having a circuit, wherein during operation of the heat recovery device a working medium circulates;
• wherein the circuit includes:
• a pump fluidically connected to the circuit and configured to convey the working medium through the circuit;
• an evaporator, arranged downstream of the pump, configured to evaporate the working medium;
• an expander, arranged downstream of the evaporator, configured to expand the working medium, the expander having a shaft configured to pick up a torque at the expander;
• a condenser, arranged downstream of the expander, configured to condense the working medium;
• a tank connected to the circuit between the condenser and the pump, the tank defining a volume for the working medium;
• an adjustor including a membrane disposed in the tank and a compressed air device fluidically connected to the membrane, the adjustor configured to change the volume of the tank for the working medium via displacing the membrane in the tank with compressed air from the compressed air device;
• a non-return valve, arranged between the tank and the condenser, configured to prevent a flow of the working medium in a direction of the condenser;
• and a controller configured to adjust the volume of the tank via actuating the adjustor and displacing the membrane in the tank;
• passing the working medium from the tank into the circuit via reducing the volume of the tank;
• flowing the working medium from the circuit into the tank via enlarging the volume of the tank;
• and
• repeatedly reducing the volume of the tank and enlarging the volume of the tank in an alternating manner via the controller during a start-up operation of the heat recovery device by actuating the adjustor and displacing the membrane in the tank such that a supplemental flow of the working medium is conveyed through the circuit, wherein the working medium is in a substantially liquid state in the circuit during the start-up operation.

A heat recovery device comprising:

• a circuit, wherein during operation of the heat recovery device a working medium circulates, wherein the circuit includes:
• a pump fluidically connected to the circuit and configured to convey the working medium through the circuit;
• an evaporator, arranged downstream of the pump, configured to evaporate the working medium;
• an expander, arranged downstream of the evaporator, configured to expand the working medium, the expander having a shaft configured to pick up a torque at the expander, and wherein the pump is drivingly connected to the expander;
• a condenser, arranged downstream of the expander, configured to condense the working medium;
• a tank connected to the circuit between the condenser and the pump, the tank defining a volume for the working medium;
• an adjustor including a membrane disposed in the tank and a compressed air device fluidically connected to the membrane, the adjustor configured to change the volume of the tank for the working medium via displacing the membrane in the tank with compressed air from the compressed air device;
• an expander bypass fluidically connected to the circuit through which the working medium bypasses the expander, the expander bypass branching off from the circuit upstream of the expander and opening into the circuit downstream of the expander;
• a control valve disposed in the expander bypass structured and arranged to adjust a flow of the working medium through the expander bypass;
• a non-return valve, arranged between the tank and the condenser, configured to prevent a flow of the working medium in a direction of the condenser;
• and
• a controller operatively connected to the adjustor, the controller configured to adjust the volume of the tank for the working medium via actuating the adjustor and displacing the membrane in the tank when the working medium in the circuit is present in two phases after a shut-down operation, until the working medium in the entire circuit is present in the same phase.