Dynamic compartmentalised heat transfer modelling for systems with biological applications

Abstract

Proper thermal management is crucial to controlling the temperature of biological systems within an optimized operating range. A biological system is comprised of a multitude of interacting facets, where a system is often disrupted as a consequence of random events such as the change in ambient temperature. In contrast the design of most human engineered chemical systems or processes may assume steady state operation and as a result is relatively straightforward to design and optimise. Yet, often steady temperature ranges are required in unsteady conditions. This sort of unsteady state system requires consideration of the dynamic changes to the conditions and are often required to be within many applications. A narrow temperature band is essential for controlling the outcomes of how biological systems’ function—thermal denaturation of biological components depend on precise control of the transport of heat. Insulin—a hormone peptide drug—is temperature sensitive and undergoes thermal fibrillation when exposed to temperatures above manufacturers' recommendations. To maintain such medication within specific temperature bands is a challenge in the face of energy intermittency from the energy crisis that South Africa is currently facing. Within this dissertation, a medical device to contain thermosensitive biological compounds is designed and modelled as a system undergoing dynamic thermal conditions. This heat transfer modelling is used as a prototyping process for designing the medical device to protect temperature sensitive medication during power outages. The simulated device, when used correctly, is able to keep medication thermally stable under 8°C during Stage 4 load shedding (7.5 hours of power outages within a 24-hour period).