The human body must stay within a certain temperature range for comfort and safety. However, challenges for thermoregulatory clothing exist for harsh application scenarios, such as full day/night cycles, frigid polar regions, and space travel.
We developed a flexible and sustainable personal thermoregulatory clothing system by integrating a flexible organic photovoltaic (OPV) module to directly acquire energy from sunlight and bidirectional electrocaloric (EC) devices. The flexible OPV-EC thermoregulatory clothing (OETC) can extend the human thermal comfort zone from 22°–28°C to 12.5°–37.6°C with a fast thermoregulation rate.
The low energy consumption and high efficiency of the EC device allows for 24 hours of controllable and dual-mode thermoregulation with 12 hours of sunlight energy input. This self-powered wearable thermoregulatory platform has a simple structure, compact design, high efficiency, and strong self-adaptability with sunlight as the sole energy source."
Flexible electrocaloric module
In their study, Wang and colleagues built up a small piece of wearable material by integrating a flexible solar cell onto a flexible electrocaloric module. The latter is a device that undergoes reversible temperature changes in response to applied electric fields.
When placed in sunlight, the solar cell harvested more than enough energy for the electrocaloric module to cool a wearer’s skin by up to 10 degrees in hot weather. Any excess energy can be stored in a small separate battery. In darkness, the device can be switched to warming mode and the stored energy used to warm the wearer’s skin by as much as three degrees. Altogether, the device can achieve thermoregulation throughout a 24 hour period...
Energy-efficient fabric helps wearers beat heat waves and cold snaps
With its active thermoregulation, the device could allow wearers to endure scorching deserts, frigid polar regions, and many climates with rapid swings in temperature
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Thermoelectric technology has been widely used for key areas, including waste-heat recovery and solid-state cooling. We discovered tin selenide (SnSe) crystals with potential power generation and Peltier cooling performance. The extensive off-stoichiometric defects have a larger impact on the transport properties of SnSe, which motivated us to develop a lattice plainification strategy for defects engineering. We demonstrated that Cu can fill Sn vacancies to weaken defects scattering and boost carrier mobility, facilitating a power factor exceeding ~100 microwatts per centimeter per square kelvin and a dimensionless figure of merit (ZT) of ~1.5 at 300 kelvin, with an average ZT of ~2.2 at 300 to 773 kelvin. We further realized a single-leg efficiency of ~12.2% under a temperature difference (ΔT) of ~300 kelvin and a seven-pair Peltier cooling ΔTmax of ~61.2 kelvin at ambient temperature. Our observations are important for practical applications of SnSe crystals in power generation as well as electronic cooling.
BY XINGYI HUANG, PENGLI LI
