To overcome fatal shortcomings of organic phase change materials (PCMs), such as leakage during work, low thermal conductivity and shortage of multiple driving ways, we propose a novel strategy to synthesize structurally, mechanically, electrically and optically anisotropic graphene aerogels (AN-GAs) by using gaseous hydrogen chloride to in situ solidify ordered graphene oxide liquid crystals followed by chemical reduction, supercritical fluid drying and annealing in an Ar atmosphere in sequence. The confined pore space and aligned wall structure of the resulting AN-GAs have benefited crystallization of organic phase change molecules and thus highly efficient phase change composites (PCCs) are fabricated with long durability and good strength. The resulting PCCs can also be driven either by applying a small voltage (1–3 V) with high electro-heat efficiency (up to 85%) or by irradiating with weak sunlight (0.8–1.0 sun) with high photo-heat efficiency (up to 77%).

Passive daytime radiative cooling (PDRC) is an emerging sustainable technology that can spontaneously radiate heat to outer space through an atmospheric transparency window to achieve self‐cooling. PDRC has attracted considerable attention and shows great potential for personal thermal management (PTM). However, PDRC polymers are limited to polyethylene, polyvinylidene fluoride, and their derivatives. In this study, a series of polymer films based on thermoplastic polyurethane (TPU) and their composite films with silica aerogels (aerogel‐functionalized TPU (AFTPU)) are prepared using a simple and scalable non‐solvent‐phase‐separation strategy. The TPU and AFTPU films are freestanding, mechanically strong, show high solar reflection up to 94%, and emit strongly in the atmospheric transparency window, thereby achieving subambient cooling of 10.0 and 7.7 °C on a hot summer day for the TPU and AFTPU film (10 wt%), respectively. The AFTPU films can be used as waterproof and moisture permeable coatings for traditional textiles, such as cotton, polyester, and nylon, and the highest temperature drop of 17.6 °C is achieved with respect to pristine nylon fabric, in which both the cooling performance and waterproof properties are highly desirable for the PTM applications. This study opens up a promising route for designing common polymers for highly efficient PDRC.

The high installation cost is the major obstacle of the commercialization of the solid oxide fuel cell for distributed power generation. This paper presents a new low cost 10-kW converter system to overcome this obstacle. The proposed system consists of an isolated dc-dc converter to boost the fuel cell voltage to 400 V dc and a pulse-width modulated inverter with filter to convert the dc voltage to two split-phase 120-V ac. The dc-dc converter uses phase shifting to control power flow through a transformer with a metal oxide semiconductor field effect transistor full bridge on the low voltage side and a voltage doubler on the high voltage side. One IPM is used to realize the voltage doubler and the dc-ac inverter. Compared to the existing fuel cell converter systems, the proposed circuit has low cost, less component count, smaller size, and reduced dc-dc converter peak current. Simulation and experimental results are demonstrated.