UC San Diego

Even with the increasing energy crisis, energy consumption for human thermal comfort is considered indispensable reflecting upon the energy utilization in heating, ventilation, and air conditioning (HVAC), which corresponds to 42.3% of energy consumption in buildings and homes in USA. This huge amount is economically equivalent to 27 billion dollars and converted into 0.55 billion dollars worth per 1℃ in the room or the office. Moreover, additional expenditure is needed to manage environmental pollution to take into account greenhouse gas emission of 670 MT CO2 produced from the same amount of energy generation. From a perspective of energy efficiency, warming up the whole building to fulfill the temperature range for thermal comfort is wasteful compared to locally heating and cooling individuals. Many thermal clothes such as active heating fabrics, cooling pads, and inner clothes have been developed for thermal comfort. However, these garments and tools can’t suggest the solution for the energy efficiency and thermal adaptive function.

To overcome these problems, we focused on physiological response of human skin, which is a principal outer having adaptive thermoregulations. Skin has a regulatory mechanism for body temperature as a function of ambient thermal condition by controlling its resistance of heat and moisture transfer. Sweating precipitates thermal emission via evaporation, and an air insulation layer controlled by geometric change of skin hair allows designated convection and conduction at skin. Inspired these two smart functions of skin, we have devised the smart fabrics, which can adjust their porosity for moisture transfer and air insulation thickness between two layers textiles as a function of ambient surroundings.

The dissertation is constructed with the steady state model for human body for defining thermal comfort, the material and the structure design for thermal adaptive textiles (TAT), the experimental result for thermal adaptive property of TAT, and the application of TAT.