An electrosurgical system (410, 510), comprising: an electrosurgical device adapted to direct energy to tissue, wherein the electrosurgical device includes an antenna assembly; a coolant supply system adapted to provide coolant fluid to the electrosurgical device, wherein the coolant supply system includes a coolant source, a first fluid-flow path fluidly-coupled to the electrosurgical device to provide fluid flow from the coolant source to the electrosurgical device, a second fluid-flow path fluidly-coupled to the electrosurgical device to provide fluid flow from the electrosurgical device to the coolant source, a diversion fluid-flow path fluidly-coupled to the first fluid-flow path and the second fluid-flow path, and a flow-control device disposed in fluid communication with the diversion fluid-flow path; at least one temperature sensor (TS1, TS2,... TSN) associated with the electrosurgical device; a connection hub providing at least one coolant connection to the electrosurgical device; an electrosurgical generator for activating the electrosurgical device; and a processor unit communicatively-coupled to the at least one temperature sensor (TS1, TS2,... TSN) and communicatively-coupled to the flow-control device, wherein the processor unit is integrated into the electrosurgical generator; wherein the processor unit is configured to control the flow-control device (50, 450) based on determination of a desired fluid-flow rate using at least one electrical signal outputted from the at least one temperature sensor (TS1, TS2,... TSN), wherein the flow-control device includes a valve including a valve body and an electromechanical actuator operatively-coupled to the valve body, the actuator is operably associated with the processor unit, the processor unit is configured to control the flow-control device by activating the actuator to selectively adjust the fluid-flow rate in the diversion fluid-flow path to effect a desired change in the flow rate in the first fluid flow path. an electrosurgical device adapted to direct energy to tissue, wherein the electrosurgical device includes an antenna assembly; a coolant supply system adapted to provide coolant fluid to the electrosurgical device, wherein the coolant supply system includes a coolant source, a first fluid-flow path fluidly-coupled to the electrosurgical device to provide fluid flow from the coolant source to the electrosurgical device, a second fluid-flow path fluidly-coupled to the electrosurgical device to provide fluid flow from the electrosurgical device to the coolant source, a diversion fluid-flow path fluidly-coupled to the first fluid-flow path and the second fluid-flow path, and a flow-control device disposed in fluid communication with the diversion fluid-flow path; at least one temperature sensor (TS1, TS2,... TSN) associated with the electrosurgical device; a connection hub providing at least one coolant connection to the electrosurgical device; an electrosurgical generator for activating the electrosurgical device; and a processor unit communicatively-coupled to the at least one temperature sensor (TS1, TS2,... TSN) and communicatively-coupled to the flow-control device, wherein the processor unit is integrated into the electrosurgical generator;