Numerical heat flow and transport simulation as a development tool for the design of isothermal microcalorimeters

Highlights: • Isothermal microcalorimeter(IMC) specially for microbiological analysis developed. • Finite element method (FEM) programmed for IMC. • Resulting spatio-temporally resolved material and energy flows describes well IMC. • FEM allows the selection and prediction of performance improvements of IMC. Numerous processes in biology and chemistry are accompanied by heat emission or consumption, which can be measured by isothermal microcalorimetry in the nano- to microwatt range and used to quantify the corresponding stoichiometry and kinetics. Sometimes these applications require special isothermal microcalorimeter (IMC), which are unaffordable e.g. microbiological routine testing. The design, construction and optimization of an IMC can be tedious and cost-intensive. It is thus suggested to accelerate and fasten the development process by numerical simulation using the finite element method (FEM). The FEM provides a complete picture of all energy and material fluxes not only temporally but also spatially resolved, which are difficult to determine experimentally. In the present work, numerical simulations starting from a rough computer design of an IMC test system were performed and combined with experimental investigations using a physical test system under laboratory conditions to better understand the heat flows in the IMC and to support the development process towards a high-performance customized IMC. A representative detailed 3D model of our physical test system was created and the numerical simulation results are compared by the measured data of the physical test system. Using our 3D numerical model, we can now simulate modifications to progressively enhance the performance of the current physical test system. We conclude that numerical simulations can help to reduce the time and costs associated with the development process of customised IMCs.