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This work focuses on the potential for waste energy recovery from exhaust gases in a diesel light-duty vehicle tested under real driving conditions, fueled with animal fat biodiesel, Gas To Liquid (GTL) and diesel fuels. The vehicle was tested following random velocity profiles under urban driving conditions, while under extra-urban conditions, the...
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Context 1
... addition to the exergy analysis, the results with a prototype of a thermoelectric generator were included in the study [16] (see Figure 2). The generator consists of a hot-side heat exchanger, a coolant circuit and 80 commercial Bi 2 Te 3 thermoelectric modules. ...
Context 2
... addition to the exergy analysis, the results with a prototype of a thermoelectric generator were included in the study [16] (see Figure 2). The generator consists of a hot-side heat exchanger, a coolant circuit and 80 commercial Bi2Te3 thermoelectric modules. ...
Citations
... The baseline waste energy power that can be recovered without heat exchangers or any modifications to the exhaust systems was quantified. In García-Contreras et al. [6], the thermoelectric potential of exhaust gases at different altitudes and with different fuels was analyzed. ...
This paper investigates the design of a thermoelectric generator for exhaust gases from internal combustion engines. Experimentally validated CFD methodology was employed. Different issues are studied, such as the influence of the replacement of the exhaust pipe for the TEG, the recirculation produced, and the influence of fins. The results show that an enlarged inlet cone reduces the recirculation and the pressure drop of the TEG, but more heat is lost across the cone walls, reducing the heat available for the thermoelectric modules. Internal straight fins aligned with the flow achieved a 3% increase in heat transfer, did not significantly increase the pressure drop in this type of device, and reduced the effects on pressure of the recirculation, lowering the overall pressure drop by 10%. An energy production of 175.9 W with 16.2 W of pressure drop power losses resulted in a net energy production of 160.7 W. A comparison with a flat-type thermoelectric generator under the same hot source conditions is also provided.
... Following similar purposes, Abbasi and Tabar [13] measured the vehicles' waste energy and attached TEG units to the exhaust for energy harvesting. García-Contreras et al. [14] validated TEG energy conversion performance from exhaust gases. ...
Thermal electricity generation (TEG) is a potential method to utilize energy emitted from the built environment. This work presents a prototype of the low-cost full-day power generation solar building component, which can be integrated as the building fabric or as a part of the solar panels. The size of the prototype is 0.04 m2. The overall cost is less than 25 USD. The prototype is tested in various environments to validate its performance. The first experiment tests its performance under the radiation of a high-temperature source, the prototype can generate the highest voltage of 0.8 V. In onsite experiments, it can reach a maximum value of 10 mW/m2 under sunlight. It can also work at night depending on the thermal radiation of the environment. It can also be used in different weather; the performance is even better than the nighttime. The experiments indicate that radiation heat transfer has a stronger influence on energy conversion than the convective heat transfer. The relative humidity has a certain influence on its performance, but there is no obvious effect of radiation heat transfer. Although the prototype has great potential, there are still limitations, and this article also discusses the problems. Meanwhile, this article also points out possible directions for improving design in the future. The results in this article might be helpful for zero-energy buildings and low-carbon buildings.
... These cycles highlight the effects of real urban, extra urban and rural driving in terms of pollutant emissions for light-duty [3] or heavy-duty vehicles [4]. The current tendency in new developments of internal combustion engines is to make engines more adiabatic [5], increasing the indicated work and the exhaust flow enthalpy, which can be later recovered via thermoelectric generators [6][7][8] or Organic Rankine Cycles [9,10]. Other trend is the hybridization of vehicles [11,12]. ...
Significant reduction in fuel consumption and NOx emissions can be achieved just by changing the driving along the road. In this paper, dynamic programming is employed to find two different driving profiles optimized for fuel consumption and NOx creation minimization in a diesel vehicle. Results, show that the fuel reduction driving cycle leads to fuel savings of 4% compared with the average consumption with arbitrary driving. The NOx reduction driving profile improves the emissions of arbitrary driving by a 34.5%. NOx oriented driving profile improves the emissions of the fuel-oriented cycle by a 38% at the expense of a fuel consumption penalty of 10%. This result points out the difficulty of a simultaneous NOx and fuel consumption reduction, stressing the efforts to be done in this field during the following years. Strategies followed and conclusions drawn from this paper are relevant concerning vehicle autonomy integration.
... The boundary can be chosen, such as to quantify exergy lost by the exhaust gases (Fern andez-Y añez et al., 2018a). The research found that up to 20e30% of exhaust gas energy could be retrieved by a thermoelectric generator (TEG) at the exhaust system of a light-duty diesel vehicle under real-world driving conditions (García-Contreras et al., 2019). Feasible recovery, due to technical limitations, was found to be about 6% (Agudelo et al., 2016). ...
The transportation sector in Brazil is a significant consumer of energy. This consumption progressed at a regular speed, even though vehicles individually become more efficient. The exergy analysis of societies conventionally consists of a single efficiency value applied to extended periods, and this value is essentially a reproduction of an instant. In this study, the exergy efficiencies are calculated for the Brazilian passenger vehicle fleet from 1970 to 2020 based on a definition of efficiency (ratio of the transport service needed to the fuel exergy consumed), which differs from traditional input/output analysis. To calculate efficiencies, some key vehicle parameters were analyzed, and their evolution was measured over time. Exergy efficiencies were low in the period, between 3.4% and 8.3%, with a recent improvement tendency. Transportation service required fell steadily until around 2010 when the trend was reversed. This formulation of efficiency should improve conventional exergy analysis applied to societies and help understand the administration of vehicle improvement and consumer choice, improving policy motivations for better resource use in the future.
... For example, reference [13] reported TEG energy recovery in a light-duty diesel vehicle, in realworld driving conditions, at different altitudes, with three different fuels; the best ratio of exergy to exhaust gas energy, 35%, was reached in extra-urban sequence, at the highest altitude during testing (2300 m), running with diesel fuel; reference [14] has investigated medium duty diesel truck in two real world cycles, urban and extra-urban, reported exhaust gas exergy potential as fuel savings of 7.2% and 12.6%, respectively. ...
A commercial vehicle was instrumented for assessing the engine operation modes on a mountain route in Romania, in a 70.4 km round trip with mean road gradients +4.2% and -4.5%. The real world test cycle was processed to find the distribution of the most frequent engine operation modes (time intervals versus n × n speed and load rankings) in order to extract a steady-state gradient road cycle. The direct injection turbocharged diesel engine has been tested on the dynamometric brake in the selected operation modes, investigating the energy recovery potential of the exhaust system. An exergy analysis has been performed by processing the variables of the exhaust gas flow rates for each operation mode (gas composition, pressure and temperature) which have been weighted with the time share of each mode in the driving cycle. The exergy exhaust potential has been evaluated by means of several indicators such as mean weighted exergy rate, weighted exergy to energy ratio and weighted exergy to fuel exergy ratio. By comparing the results to local urban and extra-urban cycles from previous works, it has been revealed that the gradient road cycle has a higher energy potential than the urban cycle, but a lower one than the extra-urban cycle.
... The most common energy sources used for energy harvesting are: mechanical and vibrational energy through piezoelectric materials [1], solar energy through photovoltaic materials [2] and thermal energy through thermoelectric materials [3]. Among them, thermoelectric generators (TEG) are advantageous because they can be used with a variety of heat sources: industrial waste heat streams [4], the human body [5], vehicle exhaust systems [6][7][8][9][10] or underground heat, for instance. ...
Solar thermoelectric generators (STEGs) are a promising technology to harvest energy for off-grid applications. A wide variety of STEG designs have been proposed with the aim of providing non-intermittent electrical generation. Here, we designed and tested a STEG 0.5 m long formed by nine commercial thermoelectric generator modules and located at ground level. Data were used to validate a numerical model that was employed to simulate a one-year cycle. Results confirmed the very high variability of energy generation during daylight time due to weather conditions. By contrast, energy generation during night was almost independent of atmospheric conditions. Annual variations of nighttime energy generation followed the trend of the daily averaged soil temperature at the bottom of the device. Nighttime electrical energy generation was 5.4 times smaller than the diurnal one in yearly averaged values. Mean energy generation values per day were 587 J d−1 (daylight time) and 110 J d−1 (nighttime). Total annual energy generation was 255 kJ. Mean electrical output power values during daylight and nighttime were 13.4 mW and 2.5 mW, respectively. Annual mean output power was 7.9 mW with a peak value of 79.8 mW.
The current work describes the derived energy and exergy of nickel oxide nano additives in Neem biodiesel blend at varying engine fuel injection timings. A VCR engine was used for combustion and energy analysis. Nickel oxide nano additives were synthesized and subjected for significance by using characterization techniques such as XRD, FESEM and EDS. Nano additives were doped in neem oil methyl ester blend with diesel in volumetric proportion of 25:75 %vol. The combustion analysis pertaining to Heat release rate and cylinder pressures were obtained at varying crank angles and were peak HRR and Pressures rates were found for Nickel oxide dosed fuels for 27 deg. bTDC. The amount of energy consumed for net-work done reduced with advancement of fuel injection timing from 23° to 27° bTDC and the reduction for Diesel, NB25, NB25 + 25 ppm of NiO and NB25 + 50 ppm of NiO was found to 1.1%, 1.03%, 3% and 3.3.% respectively. Exergy destruction was found to retarding with the usage of nickel oxide nanoadditives. The level of exergy destruction found for Diesel, NB25, NB25 + 25 ppm NiO and NB25 + 50 ppm of NiO with advancement of Injection timing from 23 deg. To 27 deg. bTDC was found to around 1.2%, 1.6%, 1.7% and 1.75% respectively.
Dünyanın birçok bölgesinde farklı mantar türleri besin kaynağı olarak kullanılmaktadır.
Ayrıca mantarlar besinsel özelliklerine ek olarak ilk medeniyetlerden günümüze kadar tıbbi
alanda da kullanılmaktadır. Biyolojik döngünün sağlanmasında çok önemli bir yeri olan
mantarlar, diğer canlılara sağladığı faydalar açısından da önemlidir. Mantarlar diğer birçok
canlı için olduğu gibi insanoğlunun yaşamında da çok önemli bir yere sahiptir. Bu çalışmada
Suillus luteus mantarının literatürde bildirilen terapötik özelliklerinin üzerinde durulmuştur. S.
luteus dünyanın birçok bölgesinde yayılış gösteren kozmopolit mantarlardandır. Özellikle
iğne yapraklı ormanlarda sonbahar ve yaz aylarında yoğun olarak bulunan mantarlardır. S.
luteus’un protokatekhuik asit, sinnamik asit, α-tokoferol , β-tokoferol ,γ-tokoferol , δ-
tokoferol, mannitol, thehalose, linoleik asit, oleik asit gibi birçok biyolojik olarak aktif
bileşikleri bünyesinde barındırdığı bildirilmiştir. Daha önce yapılan çalışmalarda S. luteus’un
antioksidan, antimikrobiyal, sitotoksik aktivite, antikanser, antiproliferatif, anti-inflammatör,
immunomodulating gibi birçok biyolojik aktiviteye sahip olduğu bildirilmiştir. Sonuç olarak
literatür verileri baz alınarak, S. luteus’un teröpatik yönden önemli doğal mantarlardan olduğu
belirlenmiştir.
It can classify mushrooms as edible, inedible and poisonous. Edible mushrooms are natural sources that are very important in terms of food. Inedible mushrooms generally come to the fore with their medicinal properties and are not consumed due to their taste. Poisonous mushrooms, on the other hand, are fungi that have toxic effects when consumed and even
contain lethal toxic compounds. In this study, the biological activities of Tricholoma sp., which is distributed worldwide as a cosmopolitan, were investigated. As a result, it was determined by the literature search that the species belonging to the Tricholoma sp. have important biological activities.
Mushrooms are a group of organisms that play an important role in the ecosystem. They play
a role in decomposing organic cover in nature. In addition to its consumption as a nutrient in
different parts of the world, it has also used in alternative medicine. Many studies supporting the use of alternative medicine in recent years have been conducted. In this study, the biological activities of Russula species were investigated. As a result of the literature studies, it is thought that Russula species can be used as natural material in pharmacological designs
