Problem: Temperature control is a critical aspect of many applications spanning numerous laboratories across the biotech, pharmaceutical and industrial sectors. Chillers and bath circulators are commonly employed to maintain the optimal temperature. The success of your hard work hinges on your temperature control solution. With numerous options currently available, covering different sizes, capacities and modes of action, identifying the best model for your specific application, while still maintaining a cost-effective protocol, can be challenging.

For example, many experimental set-ups only require external temperature control and it is a common misconception that larger bath circulators are more efficient, absorbing more heat and providing greater stability. Instead, larger bath circulators take up more space within the lab, and are generally more costly to run. Furthermore, they will take longer to reach the desired temperature, making them a less energy- and time-efficient option, especially for time sensitive applications.

Figure 1 - All of the factors important to maintaining temperature stability (heating, cooling, pumping, temperature measurement and control) are located towards the rear of the bath.A large bath reservoir does not necessarily provide increased cooling capacity or better temperature stability. Conversely, cooling capacity is actually based on the set-point temperature and compressor size, while stability is affected by both the consistency of the heat load produced by the application, and the precision with which the heating/cooling is controlled by the bath circulator.

The stability specification of the bath is ultimately determined by how well the heater and flow of the refrigerant are controlled. Essentially, to achieve the best temperature stability, heat must be removed at the same rate that it is added. In this bath circulator, Figure 1 illustrates how all of the factors important to maintaining temperature stability are located towards the rear of the bath. These elements include heating, cooling, pumping, temperature measurement and control.

Solution: The most appropriate choice for this type of use would be a bath circulator with the smallest possible reservoir that still meets the set-point temperature and cooling capacity requirements. This will lower the load when moving between set-points, improving the time taken to reach the desired temperature. As such, users will be provided with a more efficient and cost-effective method of temperature control.

The optimal temperature control solution for external applications requiring up to 500 W of heat removal would be a “bathless” circulator, such as the Thermo Scientific Polar Laboratory Chiller. These systems combine fast time to temperature with a lower cost and a smaller footprint than traditional bath circulators.

For more information, visit: www.thermoscientific.com/tctechlibrary

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