Safe and Ecological Refluxing with a Closed‐Loop Air Cooling System

Abstract

Off-the-shelf computer cooling hardware was used to construct a closed-loop air cooling system (CLACS) that is distinguished by scalability, low energy, and no tap water consumption. Constructed to be generally used with laboratory condensers, the system was tested with several common low and high boiling solvents and showed a condensation performance equivalent to conventional tap water cooling. Reaction yields were therefore unaffected. Also, long-lasting Soxhlet extractions showed no performance loss relative to conventional cooling. Optionally, the device can be assembled from low-voltage components and be powered from a battery, rendering it independent of the main power. Both investment and running costs are minimal, allowing a lab-wide adoption and elimination of the two major drawbacks of commonly employed tap water cooling: waste of drinking water and the risk of flooding.

Designing an Effective, Low-Cost, and Convenient Air-Cooled Semi-microscale and Small Scale Inverted Cone Vapor Condenser for Waterless Reflux Cooling

“…An exploration of the literature and of the marketed systems evidence a growing interest for waterless condenser systems whose reliability and ecological advantages are indeed well documented. − Commercially available small-scale Vigreux, Snyder, Findenser, and Asynt columns are advertised , as being suitable for small and semi-micro scale. However, a careful examination of these devices shows that in some cases − vapor cooling is attained by two successive heat exchanges through a confining solid wall: first vapor–liquid and then liquid–air, a pattern that strongly reduces the rate of overall heat exchange and makes the apparatus complex, difficult to clean, and expensive.…”

“…An exploration of the literature and of the marketed systems evidence a growing interest for waterless condenser systems whose reliability and ecological advantages are indeed well documented. − Commercially available small-scale Vigreux, Snyder, Findenser, and Asynt columns are advertised , as being suitable for small and semi-micro scale. However, a careful examination of these devices shows that in some cases − vapor cooling is attained by two successive heat exchanges through a confining solid wall: first vapor–liquid and then liquid–air, a pattern that strongly reduces the rate of overall heat exchange and makes the apparatus complex, difficult to clean, and expensive. Some small commercially available Vigreux, Snyder, and Asynt condensers, while featuring a single heat exchange (vapor–air), are characterized by regions of high negative curvature or by a large surface area where the liquid formed by condensation can be easily trapped by capillarity or adhesion, which can increase the holdup of the system, a highly critical parameter at the semi-micro scale.…”