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Solar radiation must be concentrated before irradiating hot sides in solar thermoelectric generators (STEGs) to increase the temperature difference between hot and cold sides and thus enhance output performance. However, concentrated solar radiation is often nonuniform. This condition affects the output performance of STEGs. Herein, a thermal–electric coupled model of STEGs was constructed to investigate the thermoelectric performance of STEGs under nonuniform solar radiation. Results demonstrate that when the concentration ratio is low, increasing nonuniformity facilitates the increase in the output power of STEGs. When the concentration ratio is 60, output power increases by a maximum of 3.05 %, whereas the average temperature difference decreases by 4.44 K. When the concentration ratio is high, STEG output power peaks under a specific nonuniformity, and some thermoelectric legs at the edges of STEGs turn into load, affecting the overall STEG output performance. When the cold-side cooling performance is poor, the solar radiation input to STEGs should be made as uniform as possible to ensure the output performance and safe operation of STEGs. The results of this study provide guidance for the design of efficient STEGs. • STEG model considering non-uniform radiation is established. • Non-uniform radiation increases efficiency by 3.05 % at concentration ratio of 60. • There is a non-uniform radiation distribution to maximize efficiency. • Heat transfer at the cold side should be enhanced under non-uniform radiation. [ABSTRACT FROM AUTHOR]

Considering the need to reduce greenhouse gas emissions, onshore wind energy is certain to play a major role in future energy systems. This topic has received significant attention from the research community, producing many estimations of Europe's onshore wind potential for capacity and generation. Despite this focus, previous estimates appear to have underpredicted both the amount of available future wind capacity as well as its performance. Foremost in this regard is the common use of contemporary, or at least near-future, turbine designs which are not fitting for a far-future context. In response to this, an improved, transparent, and fully reproducible work flow is presented here, and applied to determine a future-oriented onshore wind energy potential for Europe. Within a scenario of turbine cost and design in 2050, 13.4 TW of capacity is found to be available, allowing for 34.3 PWh of average generation per year. By sorting the explicitly-placed potential installation locations by their expected generation cost, national relationships between cost and performance versus installed capacity are found, and it is also seen that all countries possess some potential for onshore wind energy generation below 4 ct € kWh - 1. Furthermore, it is unlikely for these costs to exceed 6 ct € kWh - 1 in any future capacity scenario. • Determination of onshore wind energy potential in Europe for 2050. • Land eligibility, explicit futuristic turbine placement, and 37 simulation years. • Full potential at 13.4 TW and 34.3 PWh/a, with expected costs at or below 6 ct/kWh. • All European countries possess at least some potential below 4 ct/kWh. • Usage of futuristic turbine designs for future energy system designs is crucial. [ABSTRACT FROM AUTHOR]

This paper statistically validates a novel methodology that quantifies, qualifies and spatially allocates the waste heat potential of sewage systems on an urban district level, in all cases in which real data from the sewage system does not exist or is not publicly available. The methodology is based on open data and open source technology and can be adapted to various types of cities. The results, from the application of the methodology for an example city, show that the methodology robustly calculated the paths and waste water volumetric flow from waste water sources to the waste water treatment plant. The modelled system maps the sewage system accurately within areas that have a population density close to the average. Despite small inaccuracies in the overall mapping, the methodology is able to present a good estimation of spatially distributed waste heat from water flows of the sewage system in the example city. [ABSTRACT FROM AUTHOR]

A three-dimensional (3-D), transient, nonisothermal model of all-vanadium redox flow batteries (VRFBs) is developed by rigorously accounting for the electrochemical reactions of four types of vanadium ions (V 2+ , V 3+ , VO 2+ , and VO 2 + ) and the resulting mass and heat transport processes. Particular emphasis is placed on analyzing various heat generation mechanisms, including irreversible and reversible heat generation due to vanadium redox reactions and joule heating arising from the solid electrode and electrolyte ionic resistances. The 3-D model is validated against voltage evolution curves measured under charging and discharging processes. The model predictions compare well with the experimental data over a wide range of state of charge (SOCs), and further reveal key electrochemical and transport phenomena inside VRFBs through multidimensional contours of solid electrode/electrolyte potentials, species concentrations, and temperatures. This full 3-D comprehensive VRFB model can be applied to realistic multicell stacks to determine the optimal design and operating conditions. [ABSTRACT FROM AUTHOR]