A microfluidic system for separating biological entities includes a cooling device including a thermoelectric heat pump, a first fan, and a first heat exchanger disposed between the first fan and the thermoelectric heat pump; a first housing structure having a first shell that encases the first fan and the first heat exchanger; a microfluidic device and one or more piezoelectric transducers attached thereto; and a second housing structure reversibly attached to the first housing structure and having a second shell that encloses therein the microfluidic device and the one or more piezoelectric transducers. When the first and second housing structures are coupled, a first air passage is formed between a side of the first heat exchanger and an end of the microfluidic device, a second air passage is formed between the first fan and the piezoelectric transducers, thereby allowing air to circulate between the first and second air passages.