Efficient and consistent large-volume mixing is critical for the success of industrial bioprocesses. In this study, we characterize the performance of the single-use Xcellerex™ magnetic mixer (3000 L) in mixing while heating and cooling. We evaluated the mixing performance to find that:
- Temperature in the mixer can successfully reach the setpoints at the three volumes tested, including the minimum mixing volume (MMV), due to the integrated bottom jacket.
- The system and temperature-control unit (TCU) cools 3000 L of liquid from 40°C to 2°C in approximately 12 h and heats liquid from 2°C to 40°C in under 5 h.
- Typical bioprocess operations such as heating media from 4°C to 37°C or cooling product material from 37°C to 4°C, can be completed effectively within a single work shift.
A model was developed based on empirical data generated using the 3000 L Xcellerex™ magnetic mixer with the LAUDA Ultratemp 2505 W temperature control unit (TCU). Simulations were then performed on the 3000 L system using the other available TCU options, as well as on the 2000 L Xcellerex™ magnetic mixer, across the same selected filling volumes used for the 3000 L.
Introduction
Efficient heating and cooling in mixers is critical for industrial bioprocesses, especially at larger scale. Extended durations for temperature adjustments can significantly impact overall productivity and operational efficiency by delaying production schedules and increasing operational costs. Therefore, optimizing the heating and cooling times of the mixer is essential to ensure seamless and efficient processing, preventing it from becoming a limiting factor in the manufacturing workflow.
The Xcellerex™ magnetic mixer is a single-use system engineered to deliver high performance while meeting the demands of even the most challenging large-scale applications in the bioprocess industry. The single-use biocontainer bags designed for the system incorporate a powerful impeller for effective mixing. The magnetic mixer is equipped with a bottom jacket, which maximizes the heat exchange by covering nearly the entire tank except for the insulated door. This offers better thermal efficiency compared to most traditional mixing systems, which typically only have side-wall jackets.
In this study, we evaluated the heating and cooling performance of the magnetic mixer using a 3000 L jacketed tank with load cells. We also developed a simulation tool to model how different LAUDA TCU systems perform with the magnetic mixer; and compared the experimental results to the simulations.
Fig 1. Xcellerex™ magnetic mixer system with the LAUDA Ultratemp TCU used in this study. The LAUDA product is equipped with LAUDA Live, a cloud-based digital platform that enhances product support through intelligent networking. It offers smart features such as remote process monitoring and diagnostics to maximize the efficiency and performance of LAUDA TCUs.
MATERIALS AND METHODS
We performed the experiments with the LAUDA Ultratemp 2505 W temperature control unit (TCU), at three key volumes:
- Nominal volume (100% filling volume, which represents the worst-case scenario): 3000 L
- 50% of the nominal volume: 1500 L
- The minimum mixing volume (MMV, ~ 236 L)—see Figure 2 below.
Fig 2. Representation of the minimum mixing volumes in relation to the magnetic mixer impeller.
We set up the mixer and installed the single-use system as described in the operating instructions. We used an Xcellerex™ magnetic mixer 3000 L biocontainer bag, general use design, 6407-1067Z, which incorporates the mixing impeller.
For each volume of water used, we performed a full heating and cooling cycle starting by heating from 2°C to 40°C and then cooling from 40°C to 2°C. The TCU was operated in automatic control mode with the temperature reading of the LAUDA Pt100 temperature sensor connected to it with the process value used in the control loop.
The parameters used for the TCU were as follows:
Temperature control range: Minimum, -4.5°C; maximum, 60°C.
- Dead zone: 0.5°C: The dead zone refers to a range around the setpoint where the heating or cooling power is restricted. Outside this range, the system operates at full capacity (100% heating or cooling power). This mechanism helps prevent temperature overshooting or undershooting when the external temperature approaches the setpoint
- Quick tuning differential: 0.3°C. This parameter defines a temperature offset smaller than the dead zone, used during fine-tuning mode. Within this range, the system makes slow adjustments to maintain the setpoint. If the external temperature moves outside this range, the system increases the adjustment rate to prevent switching to full heating or cooling
Temperature sensor location
We inserted the LAUDA Pt100 temperature sensor into the standard thermowell position of the mixer at the same level of the probe represented in Figure 2 at the front of the system (standard position on all the single-use systems).
Data measurement and recording
For each experiment, we recorded the temperature from the LAUDA Pt100 temperature sensor, room temperature (RT) via an external sensor (RS PRO K Needle type), and TCU temperatures at both the inlet and outlet. Heating and cooling times were measured from the moment the TCU setpoint was changed on the TCU to the time when the setpoint was reached inside the mixer.
Simulations with our heat transfer model
A model was developed based on empirical data generated using the 3000 L Xcellerex™ magnetic mixer with the LAUDA Ultratemp 2505 W TCU. Simulations were then performed on the 3000 L system using the other available TCU options, as well as on the 2000 L Xcellerex™ magnetic mixer, across the same selected filling volumes used for the 3000 L.
In developing this simulator, we focused on key variables, such as the thermal characteristics of the TCU systems and their heating and cooling capacities. We also evaluated the mixer-specific parameters that influence the thermal processes, such as the relevant jacket area depending on fill level, heat transfer coefficient, jacket flow, and selected parameters, for example, the initial, final, max/min allowed TCU temperature.
To ensure the accuracy of the simulations, we incorporated real-world data obtained from laboratory testing, as well as detailed system specifications; this approach ensures that the simulated performance closely reflects reality as much as possible.
RESULTS AND DISCUSSION
Heating and cooling experiment results
Heating and cooling profiles at the 3000 L (100% nominal volume), 1500 L (50% nominal volume), and approx. 236 L (minimal volume) are shown in Figures 3 to 8 and Table 1.
The results show that the temperature in the mixer successfully reached the setpoints at the three volumes tested, including the MMV, due to the integrated bottom jacket.
Across the tested temperature range, the mixer system, paired with the LAUDA Ultratemp 2505 W TCU, can cool 3000 L of liquid from 40°C to 2°C in approximately 12 h. The system can heat liquid from 2°C to 40°C in 4 h and 48 min.
Fig 3. Heating performance of Xcellerex™ magnetic mixer at 3000 L mixing volume showing experimental (mixer) and simulated (simulation) data from 2°C to 40°C.
Fig 4. Cooling performance of Xcellerex™ magnetic mixer at 3000 L mixing volume showing experimental (mixer) and simulated (simulation) data from 40°C to 2°C.
Fig 5. Heating performance of Xcellerex™ magnetic mixer at 1500 L mixing volume showing experimental (mixer) and simulated (simulation) data from 2°C to 40°C.
Fig 6. Cooling performance of Xcellerex™ magnetic mixer at 1500 L mixing volume showing experimental (mixer) and simulated (simulation) data from 40°C to 2°C.
Fig 7. Heating performance of Xcellerex™ magnetic mixer at 236 L minimal mixing volume showing experimental (mixer) and simulated (simulation) data from 2°C to 40°C.
Fig 8. Cooling performance of Xcellerex™ magnetic mixer at 236 L minimal mixing volume showing experimental (mixer) and simulated (simulation) data from 40°C to 2°C.
Simulated heating and cooling profiles
The results from our simulation tool for heating and cooling transfer, along with real-world data generated using the Xcellerex™ magnetic mixer 3000 L and LAUDA Ultratemp 2505 W TCU, demonstrate that the predicted values closely match the experimental data (Table 1).
Table 1. Experimental heating and cooling times generated in Xcellerex™ magnetic mixer 3000 L with the LAUDA Ultratemp 2505 W TCU; calculated heating and cooling times with our in-house simulation tool on LAUDA Ultratemp 2505 W, 3505 W, and 5005 W TCUs for Xcellerex™ magnetic mixer 3000 L and 2000 L systems
| Filling volume | Data | LAUDA Ultratemp TCU | 40°C to 2°C (h:min) | 20°C to 4 °C (h:min) | 2°C to 40°C (h:min) | 20°C to 37°C (h:min) | |
| Xcellerex™ magnetic mixer, 3000 L | 236 L (MMV) | Experimental | 2505 W | 4:28 | 2:19 | 2:59 | 1:26 |
| Simulation | 2505 W | 4:56 | 2:44 | 2:41 | 1:25 | ||
| 3505 W | 5:03 | 2:48 | 2:40 | 1:24 | |||
| 5005 W | 5:09 | 2:51 | 2:42 | 1:25 | |||
| 1500 L (50%) |
Experimental | 2505 W | 7:47 | 3:55 | 3:48 | 1:47 | |
| Simulation | 2505 W | 8:03 | 4:04 | 3:51 | 2.01 | ||
| 3505 W | 7:53 | 3:54 | 3:51 | 2:01 | |||
| 5005 W | 7:11 | 3:49 | 3:49 | 1:60 | |||
| 3000 L (100%) |
Experimental | 2505 W | 12:00 | 6:00 | 4:48 | 1:40 | |
| Simulation | 2505 W | 11:31 | 5:48 | 4:56 | 2:20 | ||
| 3505 W | 10:21 | 5:10 | 4:56 | 2:20 | |||
| 5005 W | 9:13 | 4:38 | 4:25 | 2:17 | |||
| Xcellerex™ magnetic mixer, 2000 L | 172 L (MMV) | Simulation | 2505 W | 4:53 | 2:42 | 2:39 | 1:24 |
| 3505 W | 5:00 | 2:46 | 2:39 | 1:24 | |||
| 5005 W | 5:07 | 2:50 | 2:42 | 1:25 | |||
| 1000 L (50 %) |
Simulation | 2505 W | 6:36 | 3:22 | 3:22 | 1:46 | |
| 3505 W | 6:20 | 3:23 | 3:23 | 1:46 | |||
| 5005 W | 6:09 | 3:21 | 3:22 | 1:45 | |||
| 2000 L (100 %) |
Simulation | 2505 W | 8:41 | 4:20 | 3:53 | 1:58 | |
| 3505 W | 7:58 | 4:20 | 3:53 | 1:58 | |||
| 5005 W | 7:19 | 3:45 | 3:44 | 1:57 |
The predictive heating and cooling times of the LAUDA Ultratemp 2505 W TCU closely matched the experimental results. Therefore, the calculated heating and cooling times provided for the other TCU models can be used as indicative predictions, see Table 1 for details.
When selecting a TCU system, it is important to consider various trade-offs based on the specific need, such as the system footprint, electrical requirements, the time required to heat or cool to the desired temperature, operational costs, and the initial investment. Our solutions specialists are available to support you, offering consultations that use predicted data to help you choose the most suitable Xcellerex™ magnetic mixer and TCU for your specific needs.
Conclusion
- The results demonstrate the strong thermal performance of the Xcellerex™ magnetic mixer. Due to the integrated bottom jacket, the mixer reliably reaches temperature setpoints at 100% volume, 50% mixing volume, as well as the MMV.
- When paired with the LAUDA Ultratemp 2505 W TCU, the Xcellerex™ magnetic mixer effectively cools 3000 L of liquid from 40°C to 2°C in approximately 12 h, and heats from 2°C to 40°C in 4 h and 48 min.
- For most typical bioprocessing tasks, such as heating media from 4°C to 37°C or cooling product material from 37°C to 4°C, could be completed effectively within a single work shift.
- The simulation tool we developed for heating and cooling transfer, along with real-world data generated using the Xcellerex™ 3000 L magnetic mixer and LAUDA Ultratemp 2505 W TCU, demonstrates that the predicted values closely align with the experimental data.
CY53944-29Aug25-AN