If your laboratory is a well-established one, water baths may be some of your oldest pieces of equipment. If you manage a newly-minted start-up lab, perhaps you inherited baths as a component of your recent parting gift or your inaugural arrival package. In either case, those baths are probably still going strong and thawing or heating samples and reagents effectively, especially if they consist of a simple metal bucket and a plastic analog dial. So, when would you want to replace such a paleolithic stalwart, if ever? The answer, with all due respect to posterity and sentiment, is likely right now.
First, metallic alloy bath beads of several varieties can efficiently replace water as the medium of heat transfer for almost any extant non-circulating, non-shaking bath. Changing to beads can also mitigate contamination events that arise even when bath water is properly treated, because of issues such as seepage under tube caps. Beads are typically manufactured from recycled materials, and can be used indefinitely with only periodic ethanol cleanings. Ethanol is volatile and biodegradable, unlike many of the antibiotic/germicide solutions used to treat water, which are classified as pollutants and toxins when disposed in wastewater.
In addition to this direct environmental benefit, over time, bead baths provide energy and cost savings by circumventing the evaporative cycle that results in water cooling before it heats to the desired temperature. Finally, the incorporation of Peltier element-based instrumentation into dedicated bead baths achieves precise and rapid thermal settings and the ability to cycle accurately between high and low temperatures.
Chillers can also save time, energy, and money, in this case by using a compressor to recirculate cooled water vapor. There are also thermoelectric and Peltier-based models that bypass compressors, providing compact and relatively maintenance-free options. A chiller is a robust upgrade for reagent and sample temperature control compared to the standard ice bucket. It is also a versatile compromise in terms of cost compared to a certified laboratory refrigerator. However, the metric for their utility, and therefore replacement, is often specific to the equipment, space, or workflow to which they are dedicated. The simplest chillers cool samples below ambient temperature, which is useful for some standard biological reactions. Small-scale chillers warrant replacement when they begin to struggle to fulfill their duties, with digital displays that begin to fade, or fail to correspond accurately to the back-up thermometer temperature. Similar to baths, there are bead-based replacement options, including digital ice buckets, that can increase accuracy and decrease hassle associated with regular maintenance.
The need for complexity and scale increase substantially when the goal is managing the thermal emissions of expensive instrumentation. Laboratories, departments, and core facilities are ubiquitously enhancing their capacities for ventures both enormous and infinitesimal. Broad-scope forays into big data through next-generation sequencing, proteomics, and other applications—and ever-higher sensitivity acquisitions in microscopy and flow cytometry—necessitate creative and sustainable solutions for managing space, budget, and energy cost demands. As laboratory and departmental footprint requirements adapt to finding placements for new high-end equipment, large-scale chillers often need to be upgraded or replaced to handle the extra cooling load in small, dedicated equipment rooms. Additionally, choices of placement in equipment rooms versus laboratory floor or bench space necessitate consideration of water-cooled versus air-cooled condensers, or the addition of hot gas bypass to stabilize temperatures in sensitive applications. In these cases, it is important for lab managers and investigators to discuss experimental workflows and predicted outcomes, their dependence on temperature control, and how these factors impact purchase and replacement decisions for chiller needs.