Warming baths and chillers serve a range of duties in the lab from heating samples retrieved from cold storage to providing the optimal temperature for in vitro reactions. The nature of the sample types will usually dictate the type of device that will be best. The size and numbers of samples need to be considered as well, as does the scale of usage required. These are all considerations that make the choice of devices important.
With regard to sample type, cell culture samples may require gentle thawing or incubation which may in turn necessitate water bath agitation or fine temperature adjustment. Some water baths offer shaking options such as reciprocal or orbital shaking. Baths are typically built with either analog or digital control and, for temperature sensitive samples, with high accuracy adjustment options. For demanding temperature control applications, a circulating bath is likely best as these can often regulate temperature within ±0.1 °C.
There may be requirements for dynamic control of temperature changes as well, not only for a given sample but for the processing of samples with varying temperature demands. In this case, the heatup and cool down performance of the device is important. Decreasing the volume of the bath through the use of displacement blocks can also affect temperature change dynamics. Furthermore, the sample volume and number can affect the size of the bath needed as well as the performance.
In addition to warming baths there are combination warmer/chiller devices which can cover a wide range of temperature control from -40 to 200°C or greater. These devices typically work by circulation of specialized fluids and antifreezes, and can offer high precision in temperature control (±0.005°C). Other performance features including digital control, lockable lids, and contamination control enhancements, another frequent pain point for users.
Regardless of the temperature control requirements mentioned above, many additional aspects must be considered as well -- all wrapped around the concept of efficiency.
Laboratory space is becoming a premium and there is growing interest in equipment that operates as needed without taking up excess space. This includes efficiently sized temperature control elements and baths built-for-purpose, without excess options that are ill relevant to the intended needs. Expanded product lines and options are meant to address these concerns.
Time is another aspect that directly translates to efficiency. This may include not only temperature control efficiency, but operational and functional efficiency as well. Modern devices may include programmability, such that sample conditions can be met without constant and direct user interaction. Programming features may be further enabled by remote control via computer, tablet, or phone. Besides displaying programmed temperature settings, these devices may have alarms that indicate temperature variations or device failure. Device tracking and data logging are important as well, particularly with regard to quality control and requirements for GLP and GMP regulations.
Robust operation also directly translates to efficiency, as the device will likely be subjected to a range of applications and operators over its lifetime. Longevity is important as well – maximizing output and minimizing downtime. Energy efficiency is one more aspect to weigh over the lifetime of the instrument.
All of these efficiency considerations add up to cost of ownership. Each aspect must be balanced appropriately when reaching a decision as to which device is optimal for a given role. In accordance with the growing trend towards efficiency, the total cost of a temperature control device goes far deeper than simply the price tag.