Too easy, it's an old sling psychrometer. It's used to determine the wetbulb temperature of the air which is used in part to determine the overall performance of a cooling tower or other evaporative cooler.
Published by Tony Furst, Project Developer at Armstrong Fluid Technology
Too easy, it's an old sling psychrometer. It's used to determine the wetbulb temperature of the air which is used in part to determine the overall performance of a cooling tower or other evaporative cooler.