Heat Distribution of Aluminum Block with Profile for Portable Thermal Cycler Calculated Using Finite Element Method

Abstract

Polymerase Chain Reaction (PCR) becomes one of the essential tools during the COVID pandemic. The heart of the PCR is a thermal cycler. The thermal cycler is a temperature cycle instrument that changes and maintains the vial sample’s temperature at a specific target temperature. A simple thermal cycler can be made using thermoelectric as the heater and cooler to control the temperature state. The thermal block temperature distribution is important to make all the vials treated at the same temperature condition. The thermal distribution of an aluminum block as the thermal block for a portable PCR was calculated using the finite element method. The heat source and cooler with a power of 60W were placed at the bottom of the aluminum block. The temperature gradient inside the aluminum body, where the vial was placed, was calculated. The heating and cooling speed were calculated using the model. It was found that the temperature difference between the bottom surface and top surface of the aluminum block is 2.5°C during the transient time. The temperature distribution in a horizontal direction is homogenous, with a temperature difference among the surface being less than 0.01°C. The time required to heating from 24°C to 95°C is 31.05 seconds while cooling from 95°C to 55°C can be reached in 18.05 seconds.