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This article presents an overview of airflow velocity measurement methods applied to renewable energy. Basic measurement methods used in this field are discussed: tachometric, ultrasonic, and calorimetric anemometry. The principle of operation and basic properties of anemometers are presented, and based on publications from the last decade, a systematic review of development directions and trends in this field is made. The aim of the article is to familiarize people dealing with renewable energy problems, in particular wind energy, with the current state of knowledge in the field of anemometric measurements, properties of individual types of measuring devices, as well as directions of development of measurement tools. This will allow for the optimization of processes in the field of wind energy, in particular in the selection of the location of the energy facility, implementation of investments and control, diagnostics, and monitoring during operation. The selection of metrological tools adequate to the problem also allows for ensuring an appropriate level of work safety and environmental and ecological harmony and supporting the process of sustainable development. [ABSTRACT FROM AUTHOR]

The article presents concepts and experimental studies for an energy harvester designed to convert short, pulsating, turbulent airflows into electrical energy. Such flows occur in the vicinity of roads, highways, and railway tracks, among other places, and are caused by passing vehicles. A laboratory prototype is built in the form of a pendulum deflected from an equilibrium position by the airflow. The pendulum's oscillations are converted into electrical energy using an electrodynamic transducer. The harvester uses a magnetic system that increases the frequency of the oscillations and increases the energy efficiency of the system. The harvester can be used to power local low-power electrical devices, such as highway monitoring systems. It is possible to place a set of multiple harvesters in the vicinity of the road, creating a visual effect of reeds waving in the wind. [ABSTRACT FROM AUTHOR]

Energy transformation requires replacing power plants based on fossil raw materials with renewable energy. Energy harvesting plays an important, although not fully appreciated, role here. Distributed, local power supply systems for small receivers, based on various sources which previously dissipated energy, may contribute to changing the current energy paradigm. This article presents an overview of energy harvesting technologies and various energy sources used in this process. Particular attention was paid to sources of a less conventional nature. The aim of this article is to encourage and direct scientists with the potential to explore this topic to look for new, previously unexploited energy sources and innovative and effective methods of obtaining useful energy in the harvesting process. [ABSTRACT FROM AUTHOR]

An important contemporary challenge regarding sustainable development is the analysis of the possibilities of obtaining and recovering energy, also from unconventional areas. One such issue harvests energy from roads. This idea seems to be so attractive that numerous scientific teams around the world conduct research in this area. The author's systematic analysis of review articles from the last decade raises the question, whether harvesting energy from roads is really as attractive and promising as many researchers predict in their publications. The author hypothesizes that in last decade basically no significant progress has been made in the development and improvement of energy harvesting from roads methods and systems. In many cases, the solutions presented are more technical than scientific novelties. Known solutions are modeled and tested again and again, the systems are complex and expensive, and the energy and economic efficiency is relatively low. In this article, the author focuses on critically revealing the flaws, shortcomings, weaknesses, and erroneous assumptions of large part studies conducted in this field. Based on the criticism, it is aimed to indicate prospective directions of development and encourage researchers to look for innovative, effective solutions in the field of energy harvesting from roads. [ABSTRACT FROM AUTHOR]

Temperature waves are used in metrology to determine flow velocities, as well as the coefficient of thermal diffusion, chemical composition, and other parameters of the flowing medium. This study presents a method for precise generation of temperature waves in flows, based on digitally controlled electronic system. A mathematical model and structure of the system implementing the method is described. The system consists of a wire temperature wave transmitter, supplied by the system setting the preset temperature function in time. The mathematical model of such system, together with results of model and optimization testing are presented. The system allows one to generate temperature waves of the shape preset by a digital signal, generated by a computer-based control system. Such a system may be used in analytical instrumentation. [ABSTRACT FROM PUBLISHER]

Thermal anemometry measurements of non isothermal flows require the use of a temperature compensation or correction method. In this article, the principles of operation of methods for reduction of temperature influence on the flow velocity measurement are discussed. The study also compares the methods and discusses the conditions for their application. The advanced temperature compensation and correction methods are presented in uniform notation and concerns hot-wire anemometers operating in the most commonly used standard constant-temperature mode. [ABSTRACT FROM PUBLISHER]