This paper presents an energetically autonomous IoT sensor powered via thermoelectric harvesting. The operation of thermal harvesting is based on maintaining a temperature gradient of at least 26.31 K between the thermoelectric-generator sides. While the hot side employs a metal plate, the cold side is attached with a phase-change material acting as an effective passive dissipative material. The desired temperature gradient allows claiming power conversion efficiencies of about 26.43%, without efficiency reductions associated with heating and soiling. This work presents the characterization of a low-cost off-the-shelf thermoelectric generator that allows estimating the production of at least 407.3 mW corresponding to 2.44 Wh of available energy considering specific operation hours—determined statistically for a given geographic location. Then, the energy production is experimentally verified with the construction of an outdoor IoT sensor powered by a passively-cooled thermoelectric generator. The prototype contains a low-power microcontroller, environmental sensors, and a low-power radio to report selected environmental variables to a central node. This work shows that the proposed supply mechanism provides sufficient energy for continuous operation even during times with no solar resource through an on-board Li-Po battery. Such a battery can be recharged once the solar radiation is available without compromising sensor operation.

Purpose The purpose of this paper is to provide a comprehensive methodology and a case study about the successful integration of FCA with continuous improvement tools for strategic decision-making processes. Reliable knowledge of the condition of tangible assets and their ability to fulfill their target activities over time are required for an assertive strategical decision process. Facility condition assessment (FCA) is a recognized methodology that allows the systematic evaluation of this performance. For those companies whose primary objective is the production of goods, decisions associated with improvements on the productive system or re-adaptation of existing assets may also require the implementation of alternative methodologies, with a direct impact on the indicators of the company and therefore on the FCA. Design/methodology/approach This study presents a methodology for the integration of FCA and lean manufacturing (LM) as a tool in strategic decision-making process that involves the integration of continuous improvement processes or significant changes in the production process, in which the condition of the installation impacts decisively the productivity of the system. Findings The results of the implementation on an insecticide and herbicide production plant indicate an increase of 33 per cent in the capacity of the formulation process and over 20 per cent reduction in the internal quality claims associated with the packaging system. Practical implications Those methodological stages are applicable to facilities in which the FCA shows the need for significant reconditioning of assets, the need to increase the efficiency and/or the production capacity. This methodology integrates elements of continuous improvement and redesign of production systems. Originality/value The original value of this paper is oriented to the capacity to integrate different FCA and LM tools through the company indicators of productivity key performance indicators and, in addition, of a comprehensive illustration based on a study case.

No abstract

Reuse of wastewater, as well as recovery of valuable, toxic or harmful products in industrial discharges, still represents an important issue, not only because it reduces the effect on receiving water bodies, but also because of the economic resources it represents for industry itself. In this research, in situ regeneration of Mn2SO4 is evaluated, for its reuse as the main raw material in the original process of a fungicide plant. The regeneration is evaluated by selective recovery of Mn2+, Zn2+ and SO4= present in the wastewater produced by the industrial plant, and utilizing nanofiltration, electro-electrodialysis and chemical precipitation as separation alternatives. Each alternative was designed and evaluated technically and economically through simulations in Aspen Plus®, with data and information of the real process supplied by the company. Because zinc concentration is relatively low, its selective recovery was not attractive. The resulting Mn2SO4 solution and treated water quality in conventional alternatives were significantly poor with high costs. In contrast, nanofiltration and electro-electrodialysis alternatives generate water and by-products of higher quality and reuse potential with significantly lower costs. However, their viability depends on the membrane performance. The results were satisfactory, but future experimental studies are required to optimize the alternatives and define the correct pretreatment process.

No abstract