The University administration was so pleased with the improvements that my friends and I have made on the greenhouse that they replaced the old evaporative cooler with a brand new one. The warm outside air is drawn into the chamber by a large fan. Water flows into the reservoir in the base of the unit. The level of the water in the reservoir is controlled by a float valve. The water is pumped into a small spray unit near the top of the unit. The walls of the chamber are covered with a spongy material which is being wet by the sprayer. As the air is drawn into the chamber it passes through the moistened sponge material and some of the water evaporates, drawing heat from the air in doing so. Just like the old Boy-Scout canvas covered canteen. The cooled air is forced into the greenhouse, dropping the inside temperature below the ambient outside temperature. It was over 90F in the greenhouse. The outside air was 72F. After turning on the unit the temperature inside the greenhouse dropped to 65F. The unit has two fan speeds and is thermostatically controlled by user defined settings. This unit is Model US440B, Adobe Evaporative Air Cooler. Indeed a wonderful improvement!
