Research Projects

Global warming and frequent heat waves have created extremely harsh conditions for human survival. The combination of high heat exposure and elevated ambient temperatures makes it difficult to dissipate enough heat to maintain core body temperature within safe limits. This year, around 700 people died from heat stroke, and 40,000 cases of heat exhaustion were reported in India. Certain groups, such as construction workers, traffic police, soldiers, and delivery personnel, cannot avoid this exposure. The elderly population is even more vulnerable due to less active sweat glands. This inability to sweat and dissipate heat effectively can lead to heat exhaustion, heat stroke, and even death. Therefore, external cooling methods are necessary to increase safe exposure limits. Various types of cooling vests—such as air-cooled, liquid-cooled, evaporative cooling, and phase change material (PCM)-based vests—have been explored in the past, but none have yet been widely adopted as viable solutions. However, evaporative cooling vests (ECVs) offer significant advantages, being lightweight and providing a high cooling rate due to latent heat, compared to air-cooled, liquid-cooled, and PCM-based vests. Improvement in its design is required for better mass and energy transport with extreme heat load. There is a significant amount of radiative heat load on the ECV in addition to metabolic and convective heat. A smaller fraction of the evaporative cooling is utilized for cooling the human body. In this work, the incorporation of shading features along with improved gaps will be proposed to enhance cooling efficiency (defined as the ratio of cooling directed to the human body to the total evaporative cooling). A numerical simulation of coupled heat and mass transfer with radiative load will be conducted to investigate the influence of various design parameters, such as shade length, tilt angle, and gap width, as well as varying ambient air temperature, humidity, and solar radiation. Improvements in cooling efficiency with the optimized ECV design will be tested in a climatic chamber. These improved estimates will be used in a human thermoregulation model to evaluate human core temperature exposed to extreme heat under different conditions. The findings of this study will aid in mitigating human heat stress. These insights will contribute to reducing heat stroke-related deaths and extending safe exposure time for different segments of the population through improvements in ECV design. The survival limits of various vulnerable populations, with and without the vest, will be evaluated using a human thermoregulation model under different ambient conditions. Tilt angle adjustments will also be proposed based on climatic conditions. Warning guidelines will be prepared based on core temperature evolution. These understanding will help mitigate the adverse effects of extreme heat and minimize heat-related illnesses and deaths.