A device and method for removing heat from an object by spraying a cooling agent is disclosed. A cooling casing or a heat sink is mounted to the object. A spray nozzle is arranged to spray the cooling agent onto the cooling casing or the heat sink from a reservoir. The temperature of the object is detected. A controller receives the temperature and issues a signal to drive the spray nozzle when the detected temperature exceeds a predetermined upper temperature limit. The cooling agent is sprayed onto the cooling casing or the heat sink and evaporates by absorbing heat from the cooling casing or the heat sink thereby removing heat from the object. A fan is selectively provided for generating air flows to expel the evaporated cooling agent and thus enhancing heat removal from the object.