Characterizing hybrid active/passive heating systems for thermal microclimate control

Heating devices offer particular benefits in cold climates and to those with thermoregulatory or vasospastic disorders, like Reynaud's syndrome. Heating devices can be used to moderate a wearer's microclimate to alleviate thermal discomfort and pain, especially in the distal extremities where thermal sensitivity is the highest. Applying insulation on top of wearables with heating components can reduce both heat lost to the environment, as well as power needs for maintaining thermal comfort. Here, we evaluated one stitched, heated textile garment with eight textile insulation materials to assess heat propagation (measured by five thermistors on a mannequin hand and one in the surrounding, enclosed environment) and wearability (measured from tests of fabric weight, thickness, flexural rigidity, and permeance). Results find energy conserved by all materials, but wearability drawbacks for some strong insulators. Thicker materials generally had higher insulative properties, and reduced heat propagation to the indirect heating regions, specifically the finger and thumb. Additionally, heat propagation through to the environment was stronger than to the finger and thumb.