Flow-rate detection forms an integral component of a wide variety of analysis systems. With the micro-scale advancements of such technologies this is an area of interest, particularly for fluid-based medical applications, in which many different form-factors employing a variety of different detection methods can be seen. In this paper, an investigation into the plausibility and implications behind the application of a new calorimetric-based thermal flow-rate sensor for micro-fluidic lab-on-a-chip devices was conducted. Several variants of the design were created to identify the combination of components and input parameters yielding the best performance. Passive sensors offered a power-efficient, noise and drift resistant solution, proving stable flow-rate detection could be achieved using electrode plates in-place of the common hot-wire techniques used widely at the time. This design could also be used in-conjunction with digital computation hardware for integrated analysis and reporting on-chip without the need for expensive external hardware.