Future Technology

Advances in the performance of hybrid photovoltaic-thermoelectric generators: a review

Zahra Zamanipour — 2024-07-02

Renewable energy is becoming more apparent as a key solution to climate change, energy challenges, and economic challenges. As a result of the abundance of solar irradiance, photovoltaic power generation remains one of the most promising energy sources. Despite the wide spectrum of solar irradiance, PV solar cells are only able to convert a small part of it into electricity. The remainder of the spectrum is lost as heat waste, which increases the temperature of the PV panels. As the temperature rises, both the efficiency and lifespan of solar PV panels are reduced. To mitigate the aforementioned issue, thermoelectric generators (TEGs) are used in conjunction with solar PV systems. A TEG is a device that converts thermal energy (heat) into electricity based on the thermoelectric effect caused by a temperature gradient across the thermoelectric module. This paper presents an overview of studies on hybrid PV-TEG systems. In addition to hybrid PV-TEG systems, PV and TEG systems are briefly described. PV-TEG systems are compared with individual PV systems in terms of their major operational parameters, including temperature and power generation efficiency. Finally, an update on recent developments in PV-TEG systems is provided.

Classification of vanilla by quality using MOS gas sensors: assessing the effectiveness of wavelet time-frequency analyzer

Sherlyn Cheryl May Xin Wee — 2024-07-04

This paper presents an overview of the global vanilla industry, emphasizing vanilla’s status as the second most costly spice and the most extensively used flavoring worldwide. To satisfy global demand, there is an increasing reliance on synthetic methods for flavor extraction, raising concerns about quality and health risks due to widespread adulteration with cheaper synthetic vanillin, often misrepresented as "pure." To tackle adulteration effectively and economically, this study proposes employing a single-stage classification model trained using the transient response of an electronic nose (e-nose) equipped with four metal oxide semiconductor (MOS) gas sensors with Principal Component Analysis (PCA) and machine learning classification models to sample vanilla from various countries (Indonesia & Madagascar) and grades (Grade A & B). 33 classifiers were trained and compared based on classification and validation accuracy. Through trial and error, it was determined that the sensor response times at the 20s, 60s, and 90s marks, using Weighted KNN, contributed to 100% classification accuracy and 80% validation accuracy. A second analysis method was attempted where the sensor transient response was processed using the Wavelet Time-Frequency Analyzer. When training classification models using the processed data, the bilayer neural network yielded the highest classification accuracy of 100% and validation accuracy of 70%.

Evaluation of cumulative radiation exposure among dental workers at Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria

Ahmadu Ibrahim — 2024-09-01

Continuous surveillance for radiation protection is imperative when employing ionizing radiation-emitting devices, such as those used at Usmanu Danfodiyo University Teaching Hospital (UDUTH) in Sokoto, Nigeria. In adherence to national regulations, it is mandatory for all personnel involved in activities with ionizing radiation to participate in a regular individual dosimetric monitoring program. This study evaluates the occupational radiation exposure of dental healthcare practitioners over the course of 2017, with assessments conducted on a quarterly basis. For this purpose, the HARSHAW 4500 Reader, in conjunction with Thermoluminescent Dosimeters (TLDs), was employed for individual radiation monitoring. This method ensures precise and reliable measurements of both skin and deep tissue doses, providing comprehensive data on the cumulative annual effective dose for each worker. The findings from this investigation reveal significant variations in the cumulative radiation doses among the dental staff. The practitioner identified as DN24b recorded the highest cumulative dose at 15.60 man Sieverts (manSv), highlighting a notable exposure level within the group. Conversely, the practitioner labeled DN13 registered the lowest annual effective dose at 5.33 manSv, indicating effective adherence to radiation safety protocols. These results underscore the importance of rigorous and continuous radiation monitoring to ensure occupational safety. While the observed doses are within acceptable limits, the variation in exposure levels suggests the need for ongoing education and adherence to radiation protection principles. The study advocates for enhanced protective measures and continuous training to minimize radiation exposure and ensure the well-being of all dental healthcare workers at UDUTH.

Techno-economic analysis of a green hydrogen-firing gas turbine in Malaysia via Monte Carlo simulations

Mohammad Nurizat Rahman — 2024-10-16

Based on Malaysia's National Energy Transition Roadmap, hydrogen is important to the country's energy transition. However, studies on potential green hydrogen applications in Peninsular Malaysia are scarce, particularly in gas turbine (GT) co-firing. This gap has shaped discussions around the economic and technological aspects of green hydrogen production and co-firing. Therefore, this paper focuses on the feasibility of green hydrogen co-firing in one of Malaysia's GTs, with a special emphasis on Peninsular Malaysia, the country's primary industrial hub, which houses most of the key GTs. The study uses a Monte Carlo model to evaluate the economic and technical factors affecting green hydrogen adoption, concentrating on three target years: 2023, 2030, and 2050, representing different stages of technological deployment and market adoption of electrolyzers. Actual GT data is used to calculate future green hydrogen demand based on the turbines' technology and the percentage of hydrogen co-firing they could accommodate. Scenario I for 2023 showed the widest Levelized Cost of Hydrogen (LCOH) distribution, ranging from $3.54 to $16.82 per kg, indicating a high level of uncertainty. By 2030, the outlook improves significantly, with the conceptual co-firing system potentially obtaining an LCOH of $2.68 to $9.43 per kg. Looking ahead to 2050, the study predicts a promising future for green hydrogen co-firing, with the LCOH potentially dropping to $2.30 to $8.54 per kg, and a mode of $4.64 per kg. Sensitivity analysis also reveals shifting key cost drivers. In 2023, early-stage investments in electrolyzers are critical, while electricity prices become increasingly important in 2030 and 2050. Overall, three key cost drivers have been identified as having a significant effect on LCOH: electrolyzer power consumption, electricity price, and utilization rate, highlighting the need for industry and policymakers to concentrate on these factors when formulating new policy instruments for the green hydrogen co-firing initiative in Peninsular Malaysia's GTs.

Advancing combustion technologies and alternative fuels in hybrid electric vehicles: a pathway to high-efficiency, low-emission propulsion systems

Jamshid Moradi — 2024-11-01

In the pursuit of reducing carbon emissions and enhancing fuel efficiency, the integration of advanced combustion technologies and alternative fuels in internal combustion engines (ICEs) remains pivotal, especially when paired with electrified powertrains. This study offers a comprehensive analysis of cutting-edge combustion strategies—Gasoline Direct Injection (GDI), Gasoline Compression Ignition (GCI), and Low-Temperature Combustion (LTC)—and their transformative potential in hybrid electric vehicles (HEVs). Through a detailed examination of these technologies, we assess the thermodynamic optimizations achieved via variable valve timing, variable compression ratio, and cylinder deactivation systems. Additionally, the study investigates the viability of alternative fuels, including compressed natural gas (CNG), liquid petroleum gas (LPG), biodiesel, and hydrogen, as cleaner and more efficient energy carriers. The synthesis of these technologies with HEV platforms not only addresses emission regulations but also pushes the boundaries of thermal efficiency. We provide a critical evaluation of the hybridization benefits, focusing on fuel consumption reductions, particulate matter (PM) mitigation, and overall system efficiency improvements. By coupling multi-mode combustion with electrification, this work underscores a promising trajectory toward achieving near-zero emissions in both light and heavy-duty vehicle sectors. Furthermore, this study offers insights into future propulsion architectures, advocating for a synergistic approach between advanced ICE technologies and electric powertrains to meet stringent global climate targets.