Sub-wet bulb evaporative chiller with pre-cooling of incoming air flow
An evaporative chiller cooling water to below ambient wet bulb temperature. Sub-wet bulb chilling is achieved by pre-cooling incoming air upstream of the saturator. The incoming air is ambient air at ambient air temperature that is cooled using the coolness of the lower temperature outgoing air exiting the saturator. The pre-cooling lowers the temperature of the incoming air and lowers its wet bulb temperature below that of ambient air. The saturator water is chilled to below the ambient wet bulb temperature. The air in the saturator flows across the water as it gravity drips or flows from the top to the bottom of the saturator. The pre-cooled air flows across the saturator with the coolest air directed across the bottom of the saturator where the coldest water is flowing and with the hottest air directed across the top where the hottest water is flowing to provide gradient chilling.
1. An evaporative chiller comprising:
a saturator with a liquid inlet at an upper end and a liquid outlet at a lower end, wherein a volume of cooling liquid is drained by gravity through the saturator upon being fed into the liquid inlet, the cooling liquid having a higher temperature proximate to the upper end than proximate to the lower end to provide a temperature gradient in the cooling liquid in the saturator; and means for delivering a volume of air to the saturator at a first temperature near the liquid inlet of the saturator and a second temperature near the liquid outlet of the saturator that is lower than the first temperature and wherein the air delivered to the saturator is directed to flow through the saturator transverse to a direction of flow of the cooling liquid in the saturator; and wherein the air delivering means comprises an air-to-fluid heat exchanger comprising: a first thermal storage matrix positioned along a first side of the saturator through which the air is delivered to the saturator; a second thermal storage matrix positioned along a second side of the saturator through which the air is output from the saturator after being cooled by the cooling liquid; and means for flowing a fluid through the first thermal storage matrix from a lower portion to an upper portion, from the upper portion of the first thermal storage matrix to an upper portion of the second thermal storage matrix, through the second thermal storage matrix from the upper portion to a lower portion, and from the lower portion of the second thermal storage matrix to the lower portion of the first thermal storage matrix.
2. The chiller of claim 1 , wherein the air delivered to the saturator is pre-cooled relative to the temperature of ambient air adjacent a frame containing the saturator.
3. The chiller of claim 1 , wherein the air delivered to the saturator is delivered through an air inlet on one side of the saturator at with a temperature gradient with lower temperatures proximate to the liquid outlet and higher temperatures proximate to the liquid inlet.
4. The chiller of claim 1 , wherein the air delivering means comprises at least one fan operable at least periodically to cause the air delivered to the saturator to flow first through the first thermal storage matrix, second through the saturator, and third through the second thermal storage matrix before exiting the chiller, whereby the air is pre-cooled relative to ambient temperatures in a gradient manner by flowing through the first thermal storage matrix.