Abstract: A water recirculation system operates in a primary mode for evaporatively cooling air. When the water recirculation mode malfunctions, the controller switches a secondary once-through mode. The system includes a sump for collecting water run-off from the evaporative pads, and a pump in fluid communication with the sump. The pump transfers moisture from the sump to the distribution arrangement located at the top of the evaporative pads during the recirculation mode. An automatically operated make-up water valve delivers water to a distribution arrangement on the evaporative pads. A moisture distribution arrangement distributes moisture to the evaporative pads and an automatically operated sump drain valve retains water in the sump when closed and freely drains water from the sump when open. A water level control communicates the sump water level to a control system. A monitoring mechanism detects whether the water-recirculation system has malfunctioned or is operating correctly.

Abstract: A water recirculation system operates in a primary mode for evaporatively cooling air. When the water recirculation mode malfunctions, the controller switches a secondary once-through mode. The system includes a sump for collecting water run-off from the evaporative pads, and a pump in fluid communication with the sump. The pump transfers moisture from the sump to the distribution arrangement located at the top of the evaporative pads during the recirculation mode. An automatically operated make-up water valve delivers water to a distribution arrangement on the evaporative pads. A moisture distribution arrangement distributes moisture to the evaporative pads and an automatically operated sump drain valve retains water in the sump when closed and freely drains water from the sump when open. A water level control communicates the sump water level to a control system. A monitoring mechanism detects whether the water-recirculation system has malfunctioned or is operating correctly.