Project 11 - Enhancing evaporative cooling using 3D printed microstructures
Applying for Summer 2025
Supervisors: Dr Jack Panter and Dr Stefano Landini
School/Institute: School of Engineering, Mathematics and Physics, UEA
Introduction: In humans, the skin plays an essential role in thermal regulation, achieved both by controlling blood flow and through sweating [1]. As a response to hyperthermia (an elevated body temperature), sweating is an effective cooling strategy due to the process of evaporative cooling, a physical process whereby liquid water on the skin absorbs heat to form gaseous water vapour. In activities featuring large internal heat generation rates (namely exercise), managing evaporative cooling via sweating becomes particularly important.
To improve the efficacy of evaporative cooling, a number of textile and clothing innovations have been made to wick moisture from the skin, and evaporate this on the surface (see for example Fig. 1a and [2] for a recent review). However, all of these are limited to conform to the morphology of the human body, which is not a well-adapted shape purely for the purpose of optimising the rate of evaporative cooling. Thus, regardless of the moisture-wicking ability of these performance textiles, there is a fundamental limit to their cooling efficacy.
Interestingly, a way to overcome this limitation could potentially be found in the field of solar evaporation (see for example Fig. 1b [3]). Here, cm-scale structures are designed with um-scale surface roughness to efficiently spread water over a particularly large surface area, and achieve large evaporation rates. The aim of solar evaporation is to rapidly evaporate impure, contaminated water, which can then be condensed into pure drinking water. However, the concept could be adapted to develop evaporative coolers to enhance the cooling performance of sweating.
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Figures: 1: a Evaporative cooling effect of novel performance textiles on human skin under sweating conditions [2]. b Example solar evaporator design featuring both a conical macrostructure, and patterned microstructure [3]. c Experimental cooling efficiencies of novel thermal evaporator designs [4].
Aims and objectives: Inspired by the rapid developments in solar evaporators, in this project you will design, fabricate, experimentally test, and optimise evaporative coolers in the thermal fluids engineering laboratory at UEA.
Skills gained: You will use 3D printing with a 20-µm resolution to fabricate evaporative cooler designs, then use a range of equipment including thermal imaging cameras and temperature probes to monitor the cooling power of these designs. It is anticipated that you will then systematically study the relationship between the structural features and cooling power, leading on to a design optimisation process where you attempt to generate the most effective design. If time permits, the wind tunnel set up may also be used to measure the efficacy of the evaporative cooling under, so-called, forced convection conditions (whereby wind is blown past the structure, enhancing evaporation). Very little is currently known about how to design evaporative coolers effectively, so there is scope for a large degree of design creativity in this project (see for example Fig. 1c [4]).
References: (1) Smith, C. J., & Johnson, J. M. (2016). Responses to hyperthermia. Optimizing heat dissipation by convection and evaporation: Neural control of skin blood flow and sweating in humans. Autonomic Neuroscience: Basic and Clinical, 196, 25–36. https://doi.org/10.1016/j.autneu.2016.01.002. (2) Tian, Y., et al. (2025). Recent Advances in Next-Generation Textiles. Advanced Materials, 2417022. https://doi.org/10.1002/adma.202417022. (3) Wu, L., et al. (2020). Highly efficient three-dimensional solar evaporator for high salinity desalination by localized crystallization. Nature Communications, 11, 521. https://doi.org/10.1038/s41467-020-14366-1. (4) Dudukovic, N. A., et al. (2021). Cellular fluidics. Nature, 595(7865), 58–65. https://doi.org/10.1038/s41586-021-03603-2.