.Greenhouses.ControlSystems.Climate.Control_ThScreen_2

Information

Controller for the screen closure. The control, which is based on a state graph, opens and closes the screen depending on of the outside radiation and temperature. The screen is opened faster in warm days than cold days. The screen is closed in the same manner for cold and warm days. However, the set-point for closing the screen, which depends on the outside temperature, is different in cold than in warm months. Two PI systems are included to open a gap to control humidity and temperature at night. For humidity control, a gap of maximum 4% of the total screen width is allowed. The relative humidity set-point is set at 85%. For temperature control, a gap of maximum 2% is allowed when temperature exceeds the set-point by 1.5ºC.