Congratulations to Mr. HO Cheuk Hei Billy, an undergraduate student of the Energy and Environmental Engineering Programme under the supervision of Professor Chun Chen, on receiving the Second Prize in the Green and Sustainable Paper Award organized by the Chung Chi College, CUHK!
Paper Title: An Integrated Aerogel-Membrane System for High-Capacity, Non-Condensing Personal Cooling
Project Description:
This project presents the design, fabrication, and validation of a novel passive personal cooling system that integrates three advanced materials to solve the persistent trilemma in personal cooling: short duration, condensation formation, and inefficient heat targeting. The system combines a eutectic sodium chloride (NaCl) brine phase change material (PCM) for high-density energy storage, a hydrophobic silica aerogel layer for thermal insulation and condensation prevention, and a radiatively selective polyethylene membrane for directional heat transfer. Through systematic material selection, iterative prototyping, and rigorous experimental validation, the final prototype achieves over six to eight hours of effective cooling while eliminating moisture accumulation on user-contact surfaces. Comparative testing demonstrates a 7.7 times improvement in cooling duration over commercial benchmarks, with zero condensation under standardized environmental conditions simulating a Hong Kong summer (30°C, 70% RH). This work represents a significant advancement in passive thermal management technologies, offering a sustainable, energy-efficient personal cooling solution for ergonomic, medical, and portable applications.
Beyond personal comfort, this work offers a sustainable, energy-efficient alternative to air-conditioning; each reusable unit can save approximately 120 Wh of electricity per use, reducing carbon emissions by ~30.7 kg CO₂ annually per user based on the estimation. The system is also particularly beneficial for individuals with heat-sensitive skin conditions (e.g., heat rash or prickly heat), as its non-condensing, dry-cooling surface eliminates moisture-induced irritation, a common problem with conventional gel or ice packs. By minimizing reliance on energy-intensive air-conditioning, this technology contributes to broader environmental conservation and promotes equitable thermal comfort for vulnerable populations during heat waves or off-grid scenarios.
Figure showing the four-layer integrated system architecture. From top to bottom: radiative-selective membrane (roofing membrane), air gap, NaCl brine PCM core (encapsulated), and hydrophobic silica aerogel insulation layer. This synergistic architecture enables directional heat extraction from the user while blocking environmental heat gain and eliminating condensation.
Note: This paper describes the award-winning design as of submission. Subsequent prototyping has identified further optimization opportunities; the author is developing an improved version.