The installation of marine renewable energy devices (MREDs, wind turbines and converters of wave, tidal and ocean thermal energy) has increased quickly in the last decade. There is a lack of knowledge concerning the effects of MREDs on benthic invertebrates that live in contact with the seabed. The European common cuttlefish (Sepia officinalis) is the most abundant cephalopod in the Northeast Atlantic and one of the three most valuable resources for English Channel fisheries. A project to build an offshore wind farm in the French bay of Saint-Brieuc, near the English Channel, raised concern about the possible acoustic impact on local cuttlefish communities. In this study, consisting of six exposure experiments, three types of noise were considered: 3 levels of pile-driving and 3 levels of drilling. The objectives were to assess possible associated changes in hatching and larva survival, and behavioural and ultrastructural effects on sensory organs of all life stages of S. officinalis populations. After exposure, damage was observed in the statocyst sensory epithelia (hair cell extrusion) in adults compared to controls, and no anti-predator reaction was observed. The exposed larvae showed a decreased survival rate with an increasing received sound level when they were exposed to maximum pile-driving and drilling sound levels (170 dB re 1 μPa² and 167 dB re 1 μPa², respectively). However, sound pressure levels's lower than 163 dB re 1 μPa² were not found to elicit severe damage. Simulating a scenario of immobile organisms, eggs were exposed to a combination of both pile driving and drilling as they would be exposed to all operations without a chance to escape. In this scenario a decrease of hatching success was observed with increasing received sound levels.

Cellulose acetate (CA) is one of widely used polymers for chemical and medical applications due to its versatile physico-chemical functionalities. Although its recycle is available after a deacetylation process, the recycle process releases a huge amount of wastewater. Thus, this study investigated a direct disposal process of CA with its valorization to syngas (H₂ and CO) through pyrolysis. To construct more environmentally benign process, CO₂ was used as a co-feedstock with CA to simultaneously convert them into syngas. Pyrolysis of CA in N₂ was performed as a reference study to examine the effectiveness of CO₂ on valorization of CA. Acetic acid and methyl acetate were main volatile pyrolysates (VPs) from CA pyrolysis, and the further thermal cracking of VPs resulted in syngas and CH₄ formations under both N₂ and CO₂ conditions. To expedite syngas formations, multi-stage pyrolysis (two-stage pyrolysis) and catalytic pyrolysis were employed. With the increased thermal energy through two-stage pyrolysis, four times more production of syngas was shown, comparing to the result of a single-stage pyrolysis. With Ni catalysts, the syngas formation was the two orders of magnitude higher than the single-stage pyrolysis, and the significant enhancement of CO formation was shown in the presence of CO₂ due to combined effects of CO₂ and the Ni-based catalysts. This CO enhancement resulted from catalytically expedited gas phase reactions between CO₂ and VPs evolved from CA. In addition, the CO₂ contributed to the suppression of coke deposition on the catalyst, thereby suggesting more technical and environmental benefits of CO₂ as a reactive co-feedstock of pyrolysis in reference to N₂. Therefore, this study proved the direct and versatile technical platform to convert CA and CO₂ into syngas.

Insulation materials are essential components in construction, and their main objective is to increase the efficiency of thermal energy by minimizing internal and external thermal exchange. Accordingly, research and development studies are being actively conducted to increase the thermal resistance of insulation materials, and high-performance insulation materials that use organic chemicals have been developed after industrialization. However, thermal insulation comprising chemicals poses a potential risk of pollutant emissions and can cause health problems. In this study, five types of insulation materials and the contaminants generated from the building materials used in insulation construction were quantitatively analyzed. In addition, an empirical study on the discharge of pollutants was conducted using a test bed, and the effects of the pollutants discharged from the insulation material on the indoor environment were examined by analyzing the pollutant concentration for 90 days. In addition, we analyzed the effect of an insulation material on an indoor environment through the standard specifications. Moreover, the necessity of legal management of the emission of contaminants from insulation materials was proposed based on the empirical research results.

Solar energy will assist in lowering the price of fossil fuels. The current research is based on a study of a solar dryer with thermal storage that uses water and waste engine oil as the working medium at flow rates of 0.035, 0.045, and 0.065 l/s. A parabolic trough collector was used to collect heat, which was then stored in a thermal energy storage device. The system consisted of rectangular boxes containing stearic acid phase change materials with 0.3vol % Al₂O₃ nanofluids, which stored heat for the waste engine oil medium is 0.33 times that of the water medium at a rate of flow of 0.035 l/s which was also higher than the flow rates of 0.045 and 0.065 l/s. The parabolic trough reflected solar radiation to the receiver, and the heat was collected in the storage medium before being forced into circulation and transferred to the solar dryer. At a flow rate of 0.035 l/s, the energy output of the solar dryer’s waste engine oil medium and water was determined to be roughly 12.4, 14, and 15.1, and 9.8, 10.5, and 11.5 times lower than the crops output of groundnut, ginger, and turmeric, respectively. The energy output in the storage tank and the drying of groundnut, ginger, and turmeric crops with water and waste engine oil medium at varied flow rates of 0.035, 0.045, and 0.065 l/s were studied. Finally, depending on the findings of the tests, this research could be useful in agriculture, notably in the drying of vegetables.

Slurry fuels based on wood and coal processing and petroleum refinery waste are an environmentally friendly and economically feasible alternative to the conventional solid fuel-coal. As part of this experimental research, we compared a set of fuels (coal and coal-water slurries with and without petrochemicals) by normalizing and calculating the specific concentrations of pollutants from their combustion. The pollutant concentrations were normalized with respect to the mass of burnt fuel, the thermal energy released by combustion, specific mass emissions per unit time, specific maximum mass emissions, and specific mass emissions per 1 kg of fuel equivalent or 1 MJ of thermal energy. The key objective of this research was to develop a method for comparing composite fuels in terms of their relative environmental friendliness. As part of the research, coal combustion was notable for the peak emissions of gaseous pollutants irrespective of the fuel mass and combustion chamber temperature. When slurries were burnt, CO₂, SO₂, and NOₓ concentrations were 12–90% lower as compared to coal. The research findings established that the most promising fuel of all the slurries under study is the one based on coal slime and sawdust due to its high environmental indicators.

The present work aims to investigate the effects of various additives on the stability of graphene nanoplatelet (GnP)–based nanofluid phase change material (NFPCM) for cold thermal energy storage (CTES). The NFPCMs are prepared by dispersing six different types of surfactants (anionic, cationic, and non-ionic types) in deionized (DI) water at a mass ratio of 1:0.5 GnP to surfactant. NFPCMs can be found to be stable with a suitable surfactant even after 30 days using zeta-potential distribution, UV–vis absorption, visual inspection, and sedimentation tests at low temperature. The maximum enhancement in thermal conductivity of 8.3% and 48.3% is recorded in both liquid and solid states for the NFPCM with gum arabic (GA) respectively. The viscosity was enhanced by the dispersion of non-ionic surfactants, where the anionic surfactant (sodium dodecylbenzene sulfonate (SDBS)) NFPCM had a 29.9% lower augmentation compared to DI water. Furthermore, differential scanning calorimetry (DSC) results demonstrate that the phase change properties of the NFPCM are significantly affected depending on the surfactant type. The maximum phase change enthalpy is lowered (10.6%) in the Tween 80 NFPCM as compared to the base PCM. The long-term stability with the highest thermal transport property of the NFPCM storage unit integrated with the chiller is capable of achieving environmental pollution remediation by minimising the time it takes to charge the PCM.

Solar air heater (SAH) is simple and the greatest effective approach to utilize and convert solar energy into thermal energy for heating utilizations. The employment of artificial roughness under side of the observer surface is the key technique for augmenting heat transfer with minimal friction factor penalty. Current paper summarized different kinds of artificial roughness used in SAH, which augments its performance. In this review article, 96 research papers are cited, which provide detailed information about the effect of different geometrical parameters on heat transfer and friction factor. This paper also brings the information about the optimum roughness parameters and heat transfer and friction factor correlation developed by different investigators in tabular form. Optimum roughness parameters and empirical correlations are used for comparative analysis of heat transfer, friction factor, and thermo-hydraulic performance parameter (THPP) of different roughness geometries. The best performing roughness geometry is reported on the basis of comparative analysis. Mathematical model is developed for predicting the thermal efficiency (ηₜₕ) of roughened SAH duct.

The present research work aims to investigate the energy saving aspects in cool thermal energy storage system (CTES) by improving the thermophysical properties of deionized (DI) water. The influence of phase change enthalpy, specific heat, thermal conductivity, and cooling rate of the DI water for the dispersion of chemically functionalized multi-walled carbon nanotubes (f-MWCNT) is studied experimentally. The covalent functionalization method is used to modify the surface of the multi-walled carbon nanotubes (MWCNT) with the use of concentrated nitric acid. The nanofluid phase change materials (PCMs) in different mass concentrations (0.25%, 0.50%, and 0.75%) were prepared by dispersions of the f-MWCNT in DI water. The minimum reduction in enthalpy (4.01%) was recorded for the nano-PCM with 0.75% f-MWCNT as compared to the base PCM with 0.5% of sodium dodecyl benzene-sulfonate (10%). The thermal conductivity enhancement of 53.15% and 28.2% was recorded in both states for the nano-PCM (with 0.75%) at the temperature of − 10 °C and 5 °C respectively. Also, the enhancement of 30% and 23% in cooling rate is recorded for the dispersion of maximum concentration of f-MWCNT at the HTF temperatures of − 8 °C and − 6 °C, respectively. It is proven from the above findings that the dispersion of f-MWCNT reduces the subcooling and facilitates the running of the CTES system at a higher operating temperature.

This study investigated atmospheric changes that occurred due to changes in energy production and consumption before and during the COVID-19 pandemic. We analyzed nitrogen dioxide (NO₂), aerosol optical depth (AOD), and rainfall patterns to understand the associated changes in emissions, especially from the power generation sector, before (2018 and 2019) and during the lockdown of 2020 across Pakistan. Regression analysis indicated a strong association between energy production by thermal power plants and tropospheric NO₂ concentrations. Notably, a comparison between emission sources showed that the NO₂ emissions from a single thermal power plant were equivalent to the emissions from a major city. During the lockdown, we observed a 40% reduction in NO₂ emissions from coal-based power plants and a 30% reduction in mega- and major cities compared to the same retro in 2019. We also observed an approximate 25% decrease in AOD in the industrial and energy sectors, although no major decrease was obvious in the cities. Rainfall contributed to reducing the NO₂ concentrations during monsoon season across all power plants in Pakistan, whereas it did not significantly correlate with AOD. The findings highlight the need for appropriate management and use of renewable energy in the industrial sector and transportation systems. Future research could estimate the environmental and public health costs linked to pollution originating from thermal energy production and poor transportation infrastructure.

One of the important ways to the efficiently use of low-grade thermal energy is the adsorption refrigeration technology. However, it has some drawbacks such as low specific cooling power and coefficient of performance, especially under using the conventional adsorption pairs. Therefore, new adsorption pairs are tested in solar adsorption ice-maker and compared with other conventional pairs data from open literature to find the tendency of improving the solar adsorption ice-maker performance. The experimental test rig has been built in Upper Egypt in Qena City. Four different new adsorption pairs of granular activated carbon/R-410A, granular activated carbon/R-511A, Maxsorb III/R-410A, and Maxsorb III/R-511A are used. It is demonstrated that Maxsorb III/R-511A pair based solar adsorption ice-maker produced the highest values for specific cooling power, coefficient of performance, and ice production per 1 kg of adsorbent of approximately 226.7 W/kgₐdₛ, 0.197, and 1.96 kg/kgₐdₛ, respectively. While granular activated carbon/R-410A based solar adsorption ice-maker produced the lowest values of ice production per 1 kg of adsorbent and coefficient of performance of 1.38 kg/kgₐdₛ and 0.104, respectively. Moreover, it can be concluded that the tested pairs are feasible to be used in solar adsorption ice-maker systems, especially in such hot climate of Upper Egypt for food and vaccine preservation and storage.