Waste-liquid heat recovery

1. Apparatus for transferring heat energy from a waste-liquid, comprising:

at least one heat exchange element for transferring heat energy from waste-liquid in a first container to a first target fluid;

at least one heat pump element for transferring heat energy from waste-liquid transferred from the first container to a further container;

at least one selectively operable exit-valve element for selectively providing at least one fluid communication path for allowing waste-liquid to exit from the further container; and

at least one controller element for selectively operating the heat pump element to transfer heat energy from waste-liquid in the further container to a further target fluid and/or for selectively operating the at least one selectively operable exit-valve element.

2. The apparatus as claimed in claim 1 , wherein the at least one heat exchange element is located in the first container and the at least one heat pump element is located in the further container.

3. The apparatus as claimed in claim 1 , further comprising at least one selectively operable cut-off valve element for selectively providing or preventing fluid communication between the first container and the further container.

4. The apparatus as claimed in claim 1 , wherein the first container comprises at least one fluid receiving inlet for receiving waste-liquid.

5. The apparatus as claimed in claim 1 , further comprising at least one baffle element located in the first and/or the further container for improving at least one or more of, retention time of waste liquid, heat energy transfer from waste liquid and/or flow of waste-liquid in the first container and/or the further container.

6. The apparatus as claimed in claim 1 , wherein the first container comprises a volume equal to or greater than a volume of the further container.

7. The apparatus as claimed in claim 1 , further comprising at least one parameter sensor to provide the at least one controller element with at least one corresponding control signal.

8. The apparatus as claimed in claim 7 , wherein:

the at least one parameter sensor comprises at least one temperature sensor and/or at least one volume sensor, and

the volume sensor is at least one liquid level sensor.

9. The apparatus as claimed in claim 1 , wherein:

the at least one selectively operable exit-valve element is selectively operated by the at least one controller element when the temperature of waste-liquid in the further container is equal to or less than a predetermined low threshold temperature to allow exit of waste-liquid from the further container, or

the least one selectively operable exit-valve element is selectively operated by the at least one controller element when the temperature of waste-liquid in the further container is equal to or greater than a predetermined high threshold temperature to prevent exit of waste-liquid from the further container.

10. The apparatus as claimed in claim 1 , wherein:

the at least one selectively operable exit-valve element is selectively operated by the at least one controller element when the volume of waste-liquid in the further container is equal to or less than a predetermined low threshold volume to prevent exit of waste-liquid from the further container, or

the at least one selectively operable exit-valve element is selectively operated by the at least one controller element when the volume of waste-liquid in the further container is equal to or greater than a predetermined high threshold volume to allow exit of waste-liquid from the further container.

11. The apparatus as claimed in claim 1 , wherein:

the at least one selectively operable cut-off valve element is selectively operated by the at least one controller element when the volume of waste-liquid in the further container is equal to or greater than a predetermined high threshold volume to prevent fluid communication between the first and further container, or

the at least one selectively operable cut-off valve element is selectively operated by the at least one controller element when the volume of waste-liquid in the further container is equal to or less than a predetermined low threshold volume to provide fluid communication between the first and further container.

12. The apparatus as claimed in claim 1 , wherein:

the at least one controller element operates the at least one heat pump element to not transfer heat energy from waste-liquid in the further container when the temperature of waste-liquid in the further container is equal to or less than a predetermined low threshold temperature or

the at least one controller element operates the at least one heat pump element to transfer heat energy from waste-liquid in the further container when the temperature of waste-liquid in the further container is equal to or greater than a predetermined high threshold temperature.

13. The apparatus as claimed in claim 1 , wherein:

the at least one controller element operates the at least one heat pump element to transfer heat energy from waste-liquid in the further container when the volume of waste-liquid in the further container is equal to or greater than a predetermined high threshold volume, or

the at least one controller element operates the at least one heat pump element to not transfer heat energy from waste-liquid in the further container when the volume of waste-liquid in the further container is equal to or less than a predetermined low threshold volume.

14. The apparatus as claimed in claim 1 , wherein the first target fluid is at a temperature in the range of 1° C. to 30° C.

15. The apparatus as claimed in claim 1 , wherein the waste-liquid is at a temperature in the range of 1° C. to 90° C.

16. A method for transferring heat energy from a waste-liquid, comprising:

receiving waste-liquid in a first container;

transferring heat energy from waste-liquid in the first container to a first target fluid located in an at least one heat exchange element;

transferring waste-liquid from the first container to a further container;

selectively operating at least one heat pump element to transfer heat energy from waste-liquid in the further container to a further target fluid; and

selectively operating at least one selectively operable exit-valve element for respectively allowing or preventing waste-liquid to exit from the further container.

17. The method as claimed in claim 16 , whereby operation of the at least one heat pump element and/or the at least one selectively operable exit-valve element is selected in response to at least one sensed parameter of waste-liquid in the first container and/or the further container.

18. The method as claimed in claim 16 , further comprising operating at least one selectively operable cut-off valve element located for selectively allowing or preventing fluid communication between the first container and the further container.

19. The method as claimed in claim 18 , whereby operation of the at least one selectively operable cut-off valve is selected in response to at least one sensed parameter of waste-liquid in the first container and/or the further container.

20. The method as claimed in claim 16 , whereby:

operation of the at least one selectively operable exit-valve element to allow exit of waste-liquid from the further container is in response to a temperature of waste-liquid in the further container equal to or less than a predetermined low threshold temperature, or

operation of the at least one selectively operable exit-valve element to prevent exit of waste-liquid from the further container is in response to a temperature of waste-liquid in the further container equal to or greater than a predetermined high threshold temperature.

21. The method as claimed in claim 16 , whereby:

operation of the at least one selectively operable exit-valve element to allow exit of waste-liquid from the further container is in response to a volume of waste-liquid in the further container equal to or greater than a predetermined high threshold volume, or

operation of the at least one selectively operable exit-valve element to prevent exit of waste-liquid from the further container is in response to a volume of waste-liquid in the further container equal to or less than a predetermined low threshold volume.

22. The method as claimed in claim 16 , whereby:

operation of the at least one heat pump element to transfer heat energy from waste-liquid in the further container is in response to a temperature of waste-liquid in the further container equal to or greater than a predetermined high threshold temperature, or

operation of the at least one heat pump element to not transfer heat energy from waste-liquid in the further container is in response to a temperature of waste-liquid in the further container equal to or less than a predetermined low threshold temperature.

23. The method as claimed in claim 16 , whereby:

operation of the at least one heat pump element to not transfer heat energy from waste-liquid in the further container is in response to a volume of waste-liquid in the further container equal to or less than a predetermined low threshold volume, or

operation of the at least one heat pump element to transfer heat energy from waste-liquid in the further container is in response to a volume of waste-liquid in the further container equal to or greater than a predetermined low threshold volume.

24. The method as claimed in claim 18 , whereby:

operation of the at least one selectively operable cut-off valve element to allow transfer of waste-liquid from the first container to the further container in response to a volume of waste-liquid in the further container equal to or less than a predetermined low threshold volume, or

operation of the at least one selectively operable cut-off valve element to prevent transfer of waste-liquid from the first container to the further container in response to a volume of waste-liquid in the further container equal to or greater than a predetermined high threshold volume.