Knudsen compressor, DSMC, aerogel, solar energy
In this paper, a new energy harvesting method based on Knudsen compressor is proposed. We first study the possibility of Knudsen compressor working in near atmosphere pressure by Direct Simulation Monte Carlo (DSMC) method which described the gas flow from a molecular point of view. The gas flow against the Knudsen number is investigated by simulation to find the optimal condition for us to design a Knudsen compressor working near atmosphere pressure. The device is 1*1 m in size containing 16*62 Knudsen compressors (each compressor is 40*22*28 mm), with 16 are connected in series and 62 in parallel. A single stage Knudsen including base, aerogel membrane and Fresnel lens. The compressor can be driven by the solar radiation. Based on our simulation, in a typical tropical summer day, the device will generate 74.3W kinetic energy. Therefore, the energy conversion efficiency is 7.4 %.