Efficiency Evaluation: Measuring energy consumption in twisters, mixers, stirrers, & shakers

Wet labs employ a variety of equipment types for preparing and agitating materials. Vortex mixers, magnetic stirrers, and orbital shakers are routinely. IKA have recently released the IKA Twister (Figure 1), a product which can perform the functions of all three of these equipment types. Products such as the IKA Twister represent a response by industry to reduce the environmental impact of scientific research. Products which use less raw materials and reduce supply chain emissions are an essential component of the scientific sector becoming carbon neutral.

Equipment Performance

Working with the Learning and Research Centre at the University Bristol, several tests were carried out on the IKA Twister alongside other magnetic stirrers, orbital shakers, and vortex mixers to measure energy consumption and evaluate product efficiency. All units were monitored using the energy monitors and online monitoring platform provided by Logicall Wireless Solutions Ltd. The case study was jointly commissioned by IKA UK and Scientific Laboratory Supplies (SLS) Ltd. The first items monitored were the magnetic stirrers.

Magnetic Stirrers

Alongside the IKA Twister, two magnetic stirrers were tested. All three units stirred an 800ml flask filled with 700ml of water. Both the Hanna and SLS Lab Basics stirrers (Figure 2) were operated at their maximum revolutions per minute (RPM) only. The reason being that both units had a dial control which made it difficult to set precise set points below their maximum RPM. The IKA Twister can be set to operate at increments of 100 RPM up to a maximum of 3000 RPM. The IKA Twister was also tested at its maximum RPM and also the maximum set points of the other two models (Figure 3).
The IKA Twister can be set to operate at increments of 100 RPM up to a maximum of 3000 RPM, which is a larger range than the other two models. Therefore, the IKA Twister was tested at its own maximum RPM as well as at the maximum set points of the other two models (Figure 3).
Figure 3. Energy consumption of magnetic stirrers.
A feature of the IKA Twister is it can be linked with other IKA Twisters to form multiple position stirrers powered by a single power source (Figure 4). The energy usage of multiple position stirrers was monitored at different set points (Figure 5).

Orbital Shakers

With the addition of the TVWX Shaker attachment, MS 3.3 universal attachment, and STICKMAX II sticky pad, the IKA Twister was used as an orbital shaker. The IKA Twister was tested alongside two other orbital shakers at 200 RPM, with each orbital shaker agitating a single 250ml flask containing 100ml of water. Each model also employed a STICKMAX II to hold the flask in place (Figures 6 and 7).

Vortex Mixers

Vortex mixing was carried out by the IKA Twister by adding the TVWX attachment. The energy consumption of the IKA Twister was measured alongside two other models of vortex mixers (Figures 8 and 9). The two other vortex mixers were operated at their maximum RPM setpoints due to the limited accuracy of the basic dial to control the RPM.

Discussion

The energy consumption of the IKA Twisters was comparable to other models for both the magnetic stirring and vortex mixing tests. It is also important to note that the energy consumption figures represent 24-hour usage, meaning the hourly energy consumption of these equipment types is very low at ≤ 0.005 kWh/hr.
However, when comparing orbital shaking, there was a significant difference in platform sizes, and therefore the capacity for shaking multiple flasks must also be considered within the context of efficiency (Figure 10). With the notable differences in platform sizes, it is likely that shaking multiple flasks using the larger orbital shakers would be the more energy efficient option compared to the IKA Twister. But once again, the baseline energy consumption would still be low.

The space occupied by each model of equipment was also measured (Figure 11). With lab space being ‘prime real estate’, the potential space saving offered by using the multifunctional IKA Twister could be advantageous to end users and technical staff.
For teaching laboratories, the IKA Twister requires less space for storage, as 4-5 units can easily be stacked upon one another. Also, the ability to operate multiple IKA Twisters from a single power socket would be advantageous to laboratories with limited access to plug sockets.
The other potential advantage of using the IKA Twisters instead of the dedicated, single function equipment types could be the product’s associated emissions. The IKA Twister and the TWVX attachment have a combined weight of 1.140 kg. The SLS Lab Basics 9602 Vortex Mixer weighs 0.900 kg and the SLS Lab Basics Magnetic Stirrer weighs 0.538 kg, making their combined weight 1.438 kg. Therefore, the IKA Twister uses 0.298 kg less material whilst carrying out both functions, meaning its associated emissions could be potentially less. However, another case study to conduct a full lifecycle assessment (LCA) of these units to calculate an accurate product carbon footprint and better understand the recyclability of these units would be necessary. This may be of interest to many institutions requiring accurate data to calculate and reduce their Scope 3 emissions.

Aknowledgements

Special thanks to all those who made this study possible in particular:
Mr Josh Chapman, Scientific Laboratory Supplies Ltd.
Mr Kevin Mann, IKA UK.
Mrs Emma Foose, Mr Paul Savage and Mr. Callum Hawkins. Learning & Research Centre, University of Bristol
Miss Anna Lewis, Lab Sustainability, University of Bristol
Mr Ian Morris, Logicall Wireless Monitoring.

For further information on this study, or lab sustainability in general please contact Andy Evans, office@greenlightlabs.co.uk