Hierarchical implicit controller for shielded system in a grid

1. A retrofit external controller for controlling a system having devices consuming hot or cold thermal energy and for consuming or generating electric power supplied by an electricity distribution grid, the electricity distribution grid having constraints and target objectives, the constraints and target objectives being known to the retrofit external controller, comprising:

at least one device having an internal controller for controlling the use of the hot or cold thermal energy and for receiving values of variables as input to the internal controller wherein at least one value of a variable is accessible to the retrofit external controller,

the retrofit external controller being adapted to manipulate the at least one value of the variable and to supply the manipulated value of the variable to the internal controller to alter the behaviour of the at least one device to meet at least in part the constraints and target objectives of the electricity distribution grid,

wherein the at least one manipulated value of the variable is an accessible external data flow, an accessible external channel, or an accessible external sensor output whose manipulation steers the internal controller.

2. The retrofit external controller of claim 1 , wherein external sensor measurements or outputs and/or one or more external data channels are manipulated according to a previously learnt response function for altering or steering the internal controller operation so as to meet external objectives and constraints without overruling the internal controller, thereby guaranteeing that internal constraints of the controlled system can also be met.

3. The retrofit external controller of claim 1 , wherein the constraints and target objectives of the electricity distribution grid include any of: minimization of losses, limitations in the capacity of the grid, voltage, frequency and current stabilization.

4. The retrofit external controller of claim 3 , wherein the retrofit external controller is adapted to receive updated constraints and target objectives of the electricity distribution grid.

5. The retrofit external controller of claim 4 , wherein the updated constraints and target objectives are for local distribution grid level renewable energy source curtailment mitigation in a grid secure manner, system renewable energy source curtailment mitigation, excess renewable energy source absorption maximization using distribution grid connected flexibility within the local grid constraints, or balancing services using distribution grid connected flexibility within the local grid constraints.

6. The retrofit external controller of the claim 2 , further comprising means for learning responses of the at least one device to the manipulated value of the variable.

7. The retrofit external controller according to claim 1 , wherein a transfer function of the internal controller is unknown to the retrofit external controller.

8. The retrofit external controller according to claim 1 , wherein the retrofit external controller does not alter security based set-points, does not override security cut-outs or fuses or suppress alarms, does not override thermostats of the at least one device, or does not override local security features.

9. The retrofit external controller according to claim 1 , wherein the internal controller is part of a building management system.

10. The retrofit external controller according claim 1 , wherein the at least one value of the variable accessible to the retrofit external controller is selected from outside temperature, availability of electricity, a temperature, and or flow rate in heating, flow rate in cooling networks, voltage, frequency, currents, in electric distribution networks.

11. The retrofit external controller according to claim 1 , further comprising a filter to track drift of the at least one value of the variable.

12. A method of controlling a system having devices consuming hot or cold thermal energy and for consuming or generating electric power supplied by an electricity distribution grid, the electricity distribution grid having constraints and target objectives, at least one device having an internal controller for controlling the use of the hot or cold thermal energy and for receiving values of variables as input to the internal controller, the method comprising:

retrofitting an external controller wherein at least one value of a variable is accessible to the external controller, the retrofitted external controller manipulating the at least one value of the variable and

supplying the manipulated value of the variable to the internal controller to alter the behaviour of the at least one device to meet at least in part the constraints and target objectives of the electricity distribution grid,

wherein the at least one manipulated value of the variable is an accessible external data flow, an accessible external channel, or an accessible external sensor output whose manipulation steers the internal controller.

13. The method of claim 12 , wherein the constraints and target objectives of the electricity distribution grid include any of minimization of losses, limitations in the capacity of the grid, voltage, frequency and current stabilization.

14. The method of claim 13 , wherein the constraints and target objectives of the electricity distribution grid are updated.

15. The method of claim 14 , wherein the updated constraints and target objectives are for local distribution grid level renewable energy source curtailment mitigation in a grid secure manner, system renewable energy source curtailment mitigation, excess renewable energy source absorption maximization using distribution grid connected flexibility within the local grid constraints, or balancing services using distribution grid connected flexibility within the local grid constraints.

16. The method of claim 12 , further comprising the external controller learning responses of the at least one device to the manipulated value of the variable.

17. The method of claim 12 , further comprising filtering to track a drift in the at least one value of the variable.

18. An industrial site having a hierarchical structure with at least a first and a second controller level and at least a retrofit external controller according to claim 1 in at least one of the first and second controller level, the external retrofit controller having access to an external value of a variable and being adapted to manipulate the external value of the variable, and to supply a control signal to a further controller at a lower controller level of the hierarchical structure.

19. A non-transitory computer program product which when executed on a processor executes the method according to claim 12 .

20. A retrofit external controller for controlling a system having devices consuming a thermal energy, where said thermal energy comprises at least one member selected from the group of hot thermal energy and cold thermal energy, and for consuming or generating electric power supplied by or to an electricity distribution grid, the electricity distribution grid having constraints and target objectives, the constraints and target objectives being known to the retrofit external controller, comprising:

at least one device having an internal controller for controlling the use of the thermal energy and for receiving values of variables as input to the internal controller wherein at least one value of a variable is accessible to the retrofit external controller,

the retrofit external controller being configured to manipulate the at least one value of the variable and to supply the manipulated value of the variable to the internal controller to alter the behaviour of the at least one device to meet at least in part the constraints and target objectives of the electricity distribution grid, and

wherein the at least one manipulated value of the variable is an accessible external data flow, an accessible external channel, or an accessible external sensor output whose manipulation steers the internal controller.