Using Phase Change Materials in Clothing

Abstract

When microcapsules of phase change materials (PCMS) are added to textiles, they absorb heat energy as they change from a solid to a liquid state and release heat as they return to a solid state. This project quantifies the effect of PCMS in clothing on heat flow from the body during temperature transients. One- and two-layer body suits are constructed of a fabric/foam laminate produced with and without PCMS, and heat loss from a thermal manikin is measured as it is moved from a warm chamber to a cold chamber and back again. The results indicate that the heating and cooling effects last approximately 15 minutes. Heat released by PCMS in a cold environment decreases body heat loss by an average of 6.5 W for a one-layer suit and 13.2 W for a two-layer suit compared with non-PCM counterparts. PCM cooling effects increase body heat loss in a similar manner; therefore, PCMS in clothing provide a small, temporary heating/cooling effect during environmental transients.

Laboratory assessment of cold weather clothing

“…PCM's tend to make the garment heavier (increasing metabolic rate of the wearer and thus heat generation) and reduce the vapour permeability (Pause, 2000) thereby reducing evaporative heat loss. Shim and McCullough (2000) e.g. observed more moisture accumulation in the garments with PCM; i.e.…”

“…The presence of PCM's in garments is often noticed by consumers when gripping/feeling the fabric, though this initial grip is rather different in terms of effect than what happens during actual wear. Overall there is little evidence for a positive impact on people wearing these garments (Shim and McCullough, 2000). Most studies suggesting an effect have either measured only the fabrics or have methodological problems, in that their PCM garment differs from their control in several aspects, not just the presence of PCM.…”

“…A sample with good test results in this test may not be activated at all during actual use in garments, as it may not be placed in the precise location where it would reach the activation temperature. Several attempts have been made to use manikins for such testing, either by moving the manikin between climates (Shim and McCullough, 2000) or by changing the power to the manikin in analogy to the ASTM test (Havenith, unpublished data). In both instances it has been difficult to see effects, and those observed showed only small changes in heat loss (below 10W) which may in part have been due to other differences between the PCM and control clothing (difference in conductivity due to PCM).…”

Joining of dissimilar materials

“…The different properties of the different materials are jointly utilised to achieve the product performance needed. This trend is reported for several industries such as: Automotive [176], Aeronautics [209,276], Clothing [289], Tooling [186], Implants [217], Power generation [131], and Marine application [22]. The mix of new materials will require a systematic approach to material selection: these materials will interact with each other in new ways, and new Emerging trends in manufacturing such as light weighting, increased performance and functionality increases the use of multi-material, hybrid structures and thus the need for joining of dissimilar materials.…”

A Review of Technology of Personal Heating Garments

“…PCMs are combinations of different types of paraffins, each with different melting and crystallisation points. By changing the proportionate amount of each type of paraffin in the PCM, desired melting and freezing points can be obtained [37]. The most commonly used PCMs on the market are salt hydrates, fatty acids and esters, and various paraffins such as octadecane.…”