This paper investigates a new way of thermal loading of pyroelectric element. Pyroelectric devices produce a current when submitted to a temperature change over time. In order to stimulate a pyroelectric device with fast thermal transients we used a stream of droplets from non-miscible fluids having different temperature created in situ by a T-junction microfluidic circuit. The succession of droplets flowing over the pyroelectric element creates temperature transients, heating up and cooling down steps that induce a pyroelectric current. This scheme has demonstrated the generation of AC signal from non-miscible fluids at two different temperatures without any synchronized pumping. The device is made of a stack of PZT and silver electrodes obtained by screen-printing on microscope glass blade. This patterning technique allows the deposition of a large number of devices on large surface substrates. It is a first step toward pyroelectric power generation harvesting energy from waste heat.