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This study searches the impact of tourism growth on emission pollutants in Cyprus (north), which is a small island in the Mediterranean and has shown significant development in hotel and casino sectors in the last two decades. Results from time-series analyses reveal that an inverted U-shaped EKC hypothesis is confirmed for Cyprus with and without tourism development. Tourism also exerts positively significant and long-term effects on the levels of carbon emissions, revealing that growth in the tourism sector causes degradation in the environment.

Room occupancy prediction based on indoor environmental quality may be the breakthrough to ensure energy efficiency and establish an interior ambience tailored to each user. Identifying whether temperature, humidity, lighting, and CO2 levels may be used as efficient predictors of room occupancy accuracy is needed to help designers better utilize the readings and data collected in order to improve interior design, in an effort to better suit users. It also aims to help in energy efficiency and saving in an ever-increasing energy crisis and dangerous levels of climate change. This paper evaluated the accuracy of room occupancy recognition using a dataset with diverse amounts of light, CO2, and humidity. As classification algorithms, K-nearest neighbors (KNN), hybrid Adam optimizer–artificial neural network–back-propagation network (AO–ANN (BP)), and decision trees (DT) were used. Furthermore, this research is based on machine learning interpretability methodologies. Shapley additive explanations (SHAP) improve interpretability by estimating the significance values for each feature for classifiers applied. The results indicate that the KNN performs better than the DT and AO-ANN (BP) classification models have 99.5%. Though the two classifiers are designed to evaluate variations in interpretations, we must ensure that they have accurate detection. The results show that SHAP provides successful implementation following these metrics, with differences detected amongst classifier models that support the assumption that model complexity plays a significant role when predictability is taken into account.

Abstract This study presents and evaluates the feasibility of a novel hybridization of modified Kalina cycle, reverse osmosis desalination, and low-temperature water electrolysis utilizing geothermal energy to yield power, distilled water, and hydrogen, respectively. The scientific impact of the current work has been improved considering the features of Sabalan flash-binary geothermal wells in Iran as a real model through a case study. In addition to designing a novel setup, the smart use of multi-heat recovery technique, modifying the base cycle, and utilizing a part of generated distilled water to produce hydrogen by the electrolyzer are the other structural originalities, distinguishing the current work from the previous studies. The suggested system is scrutinized via a parametric study and optimized based on a genetic algorithm. The parametric study demonstrated that the highest sensitivity of varying the performance criteria of the whole system is attributed to the change in flash tank pressure. Moreover, the multi-objective optimization led to achieving the exergy efficiency and trigeneration gain output ratio as 51.3% and 1.7 for the system, respectively. Furthermore, the system was able to produce 4795 kW of power, 5.3 kg/h of hydrogen, and 19.9 kg/s of distilled water.

Abstract Mitigating the effects of environmental deterioration requires a focus on not just CO2 emissions from energy consumption, but also environmental pollution from industry sectors. To reach this goal, recent studies have extended ecological footprint (EF) analysis to identify the ecological drivers of various key industry sectors. The role of the phosphorus (P) industry on the EF within the environmental Kuznets curve (EKC) framework for China is the emphasis of this study. Autoregressive distributive lag (ARDL) as well as the impulse response function and robustness analysis were used to consider a time from 1985 to 2018. The study verifies the EKC hypothesis for China in both the long and the short run, and indispensable determinants are proposed to be included to assure the model’s fitness and robustness when conducting EF analysis of industry sectors. Energy consumption–based carbon emissions have been verified as the dominant contributor to EF, but P use and urbanization have a significant lagged positive influence on EF in the short run. P exports, in particular, have been highlighted as a critical driver of the EF of China’s P industry. The conducted frequency domain causality test reinforced the above findings and demonstrated bidirectional causality at different frequencies. This work suggests that formulating plausible P export policies to alleviate the conflict between the output of China’s P industry and the environmental sustainability of this industry are necessary. In this context, “multidisciplinary, multidimensional, and practical solutions” are most desirable for sustainable P management.

The utilization of biomass energy is important from both an energetic and environmental point of view. Saudi Arabia has a considerable amount of biomass waste that can be converted to renewable energy using different technologies. This study evaluated and analyzed the quantity and energy potential of biomass waste, Greenhouse gases (GHG) emissions, and cost estimation of power generation using different conversion techniques. The results showed that the annual biomass waste in Saudi Arabia could reach approximately 31.50 million tons, which can generate 15 TWh of electricity. Municipal solid waste (MSW) is the largest contribution to the total waste and total power generation potential, which is approximately 70% and 74% of the total, respectively. Although incineration of MSW has the highest cost requirements, it has the highest power generation potential compared with the other studied techniques. However, the anaerobic digestion of other biomass types has the advantages of low costs and GHG emissions and generates considerable energy. The findings of this study can support decision-makers in developing sustainability strategies using eco-friendly and economical technologies for efficient power generation from biomass wastes.

Nowadays, healthcare activities generate a significant amount of hazardous materials. One way to manage this problem without causing any pollution is to use the pyrolysis process. The objective of this experimental study is to examine the feasibility of pyrolysis technology to convert the medical waste to syngas and liquid fuel. The medical waste was dried, and then heat treated at $350 ^{\circ}\mathrm{C}$ for 120 minutes. The produced liquid fuel had a density of 0.7775 g/ml, calorific value of 46.6 MJ/kg, and flashpoint of $30 ^{\circ}\mathrm{C}$, properties similar to diesel fuel. Moreover, the resulting syngas consist of HC, CO, and CO2, which may be employed in combustion applications. Furthermore, this study proved that the pyrolysis process can be considered as an alternative solution for solving energy and medical waste issues.

This study focuses on highlighting the major effects and challenges being faced in the implementation of the green roof technique in Riyadh, Saudi Arabia. Green roofs have proven to be energy efficient, environment friendly, and economical in a long run. Due to the increasing global environment temperature, it has become necessary to implement such sustainable methods that help in the achievement of urban sustainability. Saudi Arabia has seen some reluctance in the implementation of green roofs in buildings. The reasons for not adopting this system have not been reported as yet. To study the level of awareness among the public and the challenges they are facing regarding green roofs, this study was taken up. A survey questionnaire was designed with a high level of flexibility covering the key issues, including the related areas that are affected in the daily life of a resident and also the challenges faced by the general public in the installation of such systems in their existing or new buildings. An extensive literature review and a reconnaissance survey were performed before shortlisting the major factors and challenges to be included in the survey questionnaire. An overwhelming response was received from the people of Riyadh City. Almost 94% of people agreed to the fact that green roofs enhance the aesthetics of the building, and the same number of people agreed that they play a role in controlling the air quality. On the other hand, 91% of the respondents identified the climate of the area as the biggest challenge in implementing green roofs on the buildings. The study concludes with strong recommendations for the local authorities to plan quick actions. The study shall help the building owners, city planners, and policy makers in identifying the major hurdles being faced by the residents in adopting green roofs and will help them to provide solutions to these issues.

Abstract An experimental investigation is conducted to test the thermal behavior and characteristics of R134a clathrates with additives, as phase change materials (PCMs). PCMs’ charging characteristics are analysed and evaluated for cooling applications. The formation of refrigerant clathrates is investigated due to their potential use in active as well as in passive cooling applications. PCMs are formed using R134a clathrate and distilled water with different refrigerant proportions and five different additives. The main objective of using additives is to study their potential for enhancing the clathrate formation and their thermodynamics properties under direct contact heat transfer. PCMs are formed in glass tubes and their freezing on-set and transformation time is recorded. The refrigerant R134a percentages of 15%, 20%, 25%, 30%, 35% and 40% are used to form clathrate. For the additives, ethanol, sodium chloride, magnesium nitrate hexahydrate, copper and aluminum are used. PCMs are formed using controllable constant temperature water. Time for initial on-set until the time the clathrate structure does not change (end-set) is recorded after regular intervals. The low charging time shows that the PCM requires low energy input to change its phase where as more time shows that PCM takes more energy to do so. Energy and exergy analyses are also performed to determine their utilization. A comparative study is conducted to compare the charging times for different PCMs using the suggested additives. R134a refrigerant clathrate without any additive is used as the base case for comparison. R134a proportion of 35% is found to be the best mass ratio for clathrate formation since it required the least amount of time and energy. Copper additive reduces the onset time while magnesium nitrate hexahydrate reduces the end-set time the most. Sodium chloride is found to increase the formation time, and at high mass proportions, it does not allow clathrate formation.

Abstract In this study, a hybrid system for potential electricity generation for Rohingya refugees in Kutupalong camp, Ukhia, Cox’s Bazar, Bangladesh is investigated. Six scenarios are considered, and an optimal configuration is chosen based on low cost of energy and low emission. The optimum system consists of a combination of Generator/PV Panel/Wind/Converter/Battery. The configuration has cost of energy of 0.35$ per kW, and the renewable fraction is found to be 87%. The proposed system is also environmentally friendly and the optimum system discharges less than 65%, 84%, and 61% emission when compared with grid, diesel, and kerosene respectively. From sustainability indicators, it was observed that the amount of diesel needed to be imported is 30%. Therefore, dependency on import is less, and this makes the proposed system highly reliable. Besides, this system does not use biomass to generate electricity. 87% resources come from renewable energy sources. So this system is highly sustainable. There is literally no idle time for equipment since their deployment is according to the demands of people. This idle time of equipment causes depreciation which in turn leads to less efficiency and higher cost.