Active cooling device: A flexible, lab-scale experimental unit to develop spatio-temporal temperature control strategies

step change in flow rate, with a settling time of 400 s. Setpoint tracking capability is demonstrated through a representative proportional-integral (PI) control experiment, which consistently reaches the target temperature with high reproducibility across repeated trials. Disturbance rejection performance is further validated by maintaining a 100 °C temperature setpoint under spatially varying heat loads using PI control. With a total component cost of approximately 14, 000 USD, the active cooling device presents a safe, flexible, and complete design, allowing for lab-scale assessment of the performance of custom temperature control strategies using enclosed impinging jets.