Solar Energy Engineering: Processes and Systems

Errata pdf inserted.Η βιβλιοθήκη διαθέτει αντίτυπο του βιβλίου σε έντυπη μορφή με ταξινομικό αριθμό: TJ810 .K35 2009With the threat of global warming, and the gradual depletion of petroleum supplies, solar electric power is rapidly becoming significant part of our energy mix. The range of solar cells spans different materials and different structures in the quest to extract maximum power from the device while keeping the cost to a minimum. Devices with efficiency exceeding 30% have been demonstrated in the laboratory. Solar Energy Engineering: Processes and Systems. Solar Energy Processes and Systems includes all areas of solar energy engineering. All subjects are presented from the fundamental level to the highest level of current research. The book includes subjects such as energy related environmental problems, solar collectors, solar water heating, solar space heating and cooling, industrial process heat, solar desalination, photovoltaics, solar thermal power systems and modelling of solar systems including the use of artificial intelligence systems in solar energy systems modelling and performance prediction

A review of hydrogen production through solar energy with various energy storage devices

The importance of solar energy and hydrogen lies in their provision of clean, renewable solutions for sustainable energy. Solar hydrogen production has attracted widespread attention due to its cleanliness, safety, and potential climate mitigation effects. This is the first paper that reviews various solar hydrogen production methods including solar electrolysis, solar chemical, and solar biohydrogen and their nexus with various energy storage devices. An analysis of published papers shows that solar electrolysis centralized systems face challenges in land use and infrastructure costs, but distributed systems were experiencing higher unit costs and complex maintenance. Another method, solar thermochemical production, can achieve high efficiencies but is challenged by material stability and cost. Photocatalytic and photoelectrochemical methods were constrained by factors like light absorption and system complexity. Photosynthetic organisms need innovations in genetic engineering and bioreactor design. Further to the problems outlined above, this paper gives various benefits of energy storage solutions, and their optimal construction matching was made according to the characteristics of the equipment. Despite its generally low efficiency, heat storage could be advantageous in regions with limited sunlight, providing unique benefits in cold areas. Finally, the article shows possible future research directions and perspective, which will undoubtedly be of great significance for future sustainable development goals

A review of optimization efforts on neighborhood-level energy hubs

This article discusses the critical role of neighborhood-level energy hubs (NLEHs), demonstrating how enhanced structural and modeling approaches can optimize their capacity, directly contributing to Sustainable Development Goal 7 (SDG 7). For this, the paper examines NLEHs’ current and future directions to identify key trends, gaps, and opportunities across four primary dimensions. The first dimension discusses the system structure, including multi-carrier energy resources, energy demands, conversion technologies, and storage solutions. Then, the second dimension assesses various analysis methods, including dynamics modeling, operation and control, design and planning, reliability, and resilience. The final two dimensions focus on uncertainty modeling and the corresponding solving procedures for these systems. By synthesizing insights from a broad spectrum of recent studies within these dimensions, pathways for future research to advance toward more realistic, efficient, and sustainable frameworks, thereby accelerating progress toward the energy efficiency target outlined in SDG 7 are identified and argued.</p

An evaluation of low volume high-intensity intermittent training (HIIT) for health risk reduction in overweight and obese men

Both sprint interval training (SIT) and high-intensity intermittent training (HIIT) have been described as time-efficient strategies for inducing favourable metabolic and cardiorespiratory adaptations in healthy and diseased participants. BACKGROUND: To date, little attention has been given to profiling the potential health benefits of HIIT or modified HIIT training within overweight and obese cohorts with particular focus on inflammation. Within this pilot trial, we tested the hypothesis that 6 sessions of HIIT performed over 2 weeks with 1-2 days’rest would improve aerobic capacity, glucose metabolism and inflammatory profile in an overweight and obese male cohort. Additionally, we profiled the potential health benefits of 4 HIIT sessions performed over the same period. METHODS: 18 overweight or obese males (BMI = 31.2 ± 3.6; V̇O2 = 30.3 ± 4.4 ml.kg.min-1) were studied before and 72 h after HIIT. Training sessions consisted of 10 x 1 min intervals at 90% HRpeak separated by 1 min recovery periods. Exercise was performed either 6 (group 1, n = 8) or 4 (group 2, n = 10)times over a 2 week period. RESULTS: After training no changes were detected from baseline for body composition, aerobic capacity, glucose metabolism or inflammatory profile(p > 0.05) in either group. CONCLUSION: Both 6 and 4 sessions of HIIT performed over a 2-week period are ineffective in improving selected health markers within an overweight and obese cohort

Appetite regulatory hormone responses on the day following a prolonged bout of moderate-intensity exercise

Exercise increases energy expenditure however acutely this does not cause compensatory changes in appetite or food intake. This unresponsiveness contrasts the rapid counter-regulatory changes seen after food restriction. The present investigation examined whether corrective changes in appetite-regulatory parameters occur after a time delay, namely, on the day after a single bout of exercise. Nine healthy males completed two, two-day trials (exercise & control) in a random order. On the exercise trial participants completed 90 min of moderate-intensity treadmill running on day one (10:30–12:00 h). On day two appetite-regulatory hormones and subjective appetite perceptions were assessed frequently in response to two test meals provided at 08:00 and 12:00 h. Identical procedures occurred in the control trial except no exercise was performed on day one. Circulating levels of leptin were reduced on the day after exercise (AUC 5841 ± 3335 vs. 7266 ± 3949 ng− 1·mL− 1 · 7 h, P = 0.012). Conversely, no compensatory changes were seen for circulating acylated ghrelin, total PYY, insulin or appetite perceptions. Unexpectedly, levels of acylated ghrelin were reduced on the exercise trial following the second test meal on day two (AUC 279 ± 136 vs. 326 ± 136 pg− 1·mL− 1 · 3 h, P = 0.021). These findings indicate that short-term energy deficits induced by exercise initially prompt a compensatory response by chronic but not acute hormonal regulators of appetite and energy balance. Within this 24 h time-frame however there is no conscious recognition of the perturbation to energy balance

A review of solar hybrid photovoltaic-thermal (PV-T) collectors and systems

In this paper, we provide a comprehensive overview of the state-of-the-art in hybrid PV-T collectors and the wider systems within which they can be implemented, and assess the worldwide energy and carbon mitigation potential of these systems. We cover both experimental and computational studies, identify opportunities for performance enhancement, pathways for collector innovation, and implications of their wider deployment at the solar-generation system level. First, we classify and review the main types of PV-T collectors, including air-based, liquid-based, dual air–water, heat-pipe, building integrated and concentrated PV-T collectors. This is followed by a presentation of performance enhancement opportunities and pathways for collector innovation. Here, we address state-of-the-art design modifications, next-generation PV cell technologies, selective coatings, spectral splitting and nanofluids. Beyond this, we address wider PV-T systems and their applications, comprising a thorough review of solar combined heat and power (S–CHP), solar cooling, solar combined cooling, heat and power (S–CCHP), solar desalination, solar drying and solar for hydrogen production systems. This includes a specific review of potential performance and cost improvements and opportunities at the solar-generation system level in thermal energy storage, control and demand-side management. Subsequently, a set of the most promising PV-T systems is assessed to analyse their carbon mitigation potential and how this technology might fit within pathways for global decarbonization. It is estimated that the REmap baseline emission curve can be reduced by more than 16% in 2030 if the uptake of solar PV-T technologies can be promoted. Finally, the review turns to a critical examination of key challenges for the adoption of PV-T technology and recommendations