A method for operating at least one distributed energy resource comprising a refrigeration system

A method for operating at least one distributed energy resource comprising a refrigeration system with at least one compressor, at least one heat rejecting heat exchanger, and two or more cooling entities, each cooling entity comprising an evaporator and an expansion valve controlling a supply of refrigerant to the evaporator, the method comprising the steps of:

• a smart-grid setup requesting information regarding expected minimum power consumption and/or expected maximum power consumption of the refrigeration system during a defined future time interval, from the distributed energy resource,
• for each of the cooling entities, a controller of the distributed energy resource estimating a power consumption contribution originating from the cooling entity,
• for each of the cooling entities, the controller of the distributed energy resource determining whether the cooling entity is in a state in which the evaporator of the cooling entity receives refrigerant or in a state in which the evaporator of the cooling entity is not receiving refrigerant, and determining whether or not the cooling entity is ready to switch state,
• the controller of the distributed energy resource calculating an expected minimum power consumption and/or an expected maximum power consumption of the refrigeration system during the defined future time interval, based on the estimated power consumption contributions of the cooling entities, and based on the determined states of the cooling entities and whether or not the cooling entities are ready to switch state,
• the controller of the distributed energy resource transmitting the calculated expected minimum power consumption and/or expected maximum power consumption of the refrigeration system to the smart-grid setup,
• the smart-grid setup transmitting a power reference to the distributed energy resource, the power reference being within a power interval defined by the transmitted expected minimum power consumption and/or expected maximum power consumption, and
• the distributed energy resource controlling the cooling entities using the power reference received from the smart-grid setup as a setpoint value for the power consumption of the refrigeration system, during the defined time interval.