Arduino-based night return mechanism for passive solar trackers

<p>Solar trackers are support platforms that keep photovoltaic panels facing the sun by following the sun from dusk to dawn. There exist active solar trackers that make use of motors and gears to orientate the photovoltaic panels towards the sun; and passive solar trackers that operate through the differential heating of the fluid in the tracking rack to follow the sun. Passive solar trackers suffer from the lack of a night return mechanism and a slow wake-up response in the mornings due to the limitations on the surface inclination angle of the rack. This paper seeks to address these issues by proposing an Arduino-based night return mechanism for passive solar trackers. An energy-saving heating element such as the ultra heating fabric manufactured by WireKinetics Co. is installed on the west-side canister of the tracker. Before dawn, the fabric is automatically heated and this will force the refrigerant in the west-side canister to vaporize and cool in the east- side canister, forcing the tracker to return and face eastward before sunrise. The night return mechanism is designed and simulated using Proteus profesional. Simulation results show that this system can significantly optimize the function of passive solar trackers.</p>

Novel multi-zone self-heated composites tool for out-of-autoclave aerospace components manufacturing

In this paper, a multi-zone self-heating composite tool is developed to manufacture out-of-autoclave complex and high-quality business jet lower wing stiffened composite panel. Autoclave manufacturing is regarded as a benchmark for manufacturing aerospace-grade composite parts. However, high accruing operational costs limit production rates thereby not being practical for smaller-scale companies. Therefore, significant work towards developing out-of-autoclave manufacturing is underway. In this study, a production line tool is developed with embedded heating fabric that controls temperature at the desired zones, replacing the need for autoclave cure. It investigates and identifies the optimal design parameters of the self-heating setup namely the placement of the heating fabric, zones, thermal management system, temperature distribution, heating rate and thermal performance using a thermal FEA model. The associated thermal characterisation of the tooling material and the part are measured for accurate simulation results. The design developed in this study will be used as production guideline for the actual tool.

Multi-scale modeling and thermal transfer properties of electric heating fabrics system

Purpose The purpose of this paper is to investigate the thermal transfer properties of electric heating fabric system which contains heating units or conductive yarns by numerical simulation, in order to optimize and evaluate the thermal performance of heating clothing. Design/methodology/approach Two kinds of FEM models are created by ANSYS system: macro-scale models of the fabrics system with heating units and air layer; and meso-scale models of the plain-woven fabrics were established embedded with the stainless yarns. In the macro-scale model, the interior and surface temperature field distribution were simulated and analyzed based on different heating unit size, heating power, heating region, air layer thickness and ambient temperature. For meso-scale models, the effects of the conductive yarns temperature, covering fabrics and pore-filling material on the temperature field distribution were simulated and analyzed. Findings With the increasing of the air layer thickness or the effective conductivity, the heat transfer along the direction of fabric thickness decreases gradually. The heat transfer along the fabric plane can be increased by dispersing the heating region. With the increasing of the conductive yarns’ temperature or the covering fabrics’ conductivity, the heat transfer distance along the fabric warp direction can be increased. Filling the internal pores of the fabric with 10 wt% SiC/TPU hybrid materials can effectively increase the in-plane heat transfer and improve the temperature uniformity on the surface of heated fabrics. Originality/value The finite element method was used to establish the simulation models of the heating fabric systems. The influence of several parameters on the thermal performance was analyzed and discussed, as well as the internal and external temperature distribution in the macro and micro scales models.