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.

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.

Solar energy is a promising form of energy that has the potential to meet all of the world’s energy needs. Only half of the sun’s energy reaches the earth’s surface, even though it is more enough for meeting the world’s energy need. Though there is a great deal of solar energy utilization technologies available, solar parabolic dish collector system got researchers focus because of its higher thermal energy conversion efficiency and its unique advantages. Several researchers have been enlightening new and emerging technologies in several countries. Hence, the authors would like to emphasize the progress in this while exercising an extensive review of different solar concentrating techniques using solar parabolic dish collector in order to produce heat and electrical power using direct and indirect energy conversion devices with wide range of applications. Their design advancement and progress applications in recent years particularly in related field are discussed too.

The balanced amelioration of mechanical characteristics of fat clay with an additive refers to the attainment of high strength without compromising ductility, which is unattainable by solitary usage of a cementing additive. For this purpose, an amalgamated binary admixture (ABA) is proposed by assimilating shredded face mask (FM) waste, which is posing serious environmental concerns these days, with a cementitious waste material, i.e., silica fume (SF). However, for such ABA, the optimization of mix design is desirable because an excessive amount of one component could disturb the required balance. To address this issue, response surface methodology (RSM) is used in the current study, which is a strong technique used during the process of production to develop, improve, and optimize product inputs. Several experiments are designed and conducted to evaluate mechanical responses, i.e., unconfined compressive strength (qᵤ), brittleness index (IB), deformability index (ID), and California bearing ratio (CBR) value, of treated fat clay by varying mix designs of ABA. Based on the test results, mathematical models are developed which are found to be statistically valid to predict the subjected responses using SF and FM as inputs. Afterward, an optimized mix design is determined by integrating developed models with a desirability function model and setting maximization of strength and ductility as the optimization goals. An ABA having 7.9% SF and 1.2% FM is observed to provide the highest strength and ductility for multiple applications, i.e., road and buildings, with desirability factor close to unity; responses of which are also validated by performing tests. Furthermore, analysis of cleaning aspect shows that the use of optimized ABA in place of cement for subgrade improvement of 1 km two-lane road could avoid CO₂ emission of around 79,032 kg of C, save 42,720 kWh and 1174.8 GJ of electrical and thermal energy, respectively, and clean 43 Mg of FM waste; however, astute protocols of COVID-19 FM waste handling and disinfection are needed to be established and followed.

Although the solar distillers are one of the economic solutions for addressing the freshwater shortage problem around the world, these devices suffer from low productivity. In this paper, a simple and inexpensive modification was made in the tubular solar still (TSS) to improve its productivity. The adjustment is to tilt the glass cylinder, something to help the droplets move down and collect them as a distillate. The modified inclined TSS was abbreviated by ITSS. Then, three different inclination angles were investigated (2°, 4°, and 6°), and the performance of ITSS with these inclination angles was compared with that of TSS without inclination angle (0°). Moreover, to obtain additional productivity for ITSS, the basin was painted with a mixture of matte black paint with nanomaterials. Three types of nanomaterials were studied (copper oxide nanoparticles, titanium oxide nanoparticles, and silver nanoparticles). For further improvement in ITSS productivity, Ag nanoparticles mixed with phase change material (PCM) were employed beneath the ITSS base to work as thermal energy storage material. Experimental results revealed that the highest average daily productivity rise for ITSS over TSS was observed when tilting ITSS by 6°, where the daily productivity rise and thermal efficiency reached 24% and 37.6%, respectively. Besides, the average increase in daily distillate of ITSS was 34%, 30%, and 28.5% when using Ag, CuO, and TiO₂, respectively, compared to that of TSS. Moreover, ITSS with Ag provided the best thermal efficiency compared to the other operating cases, where it was 39.1%. In addition, ITSS-PCM-Ag showed a daily productivity of 62.5% more than that of TSS and a thermal efficiency of 43.5%.

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.

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.

The intermittent nature of solar radiation requires a thermal energy storage (TES) system for reducing the mismatch between energy demand and supply. Solar water heating (SWH) systems can help save up to 90% of the utilized energy for water heating. In this study, a compound parabolic concentrator (CPC) solar collector has been coupled to three different configurations of TES system. A comprehensive analysis on the effects of PCMs arrangements in TES systems viz three PCMs (case 1) and five PCMs (case 2) on the energy efficiency, exergy efficiency, and overall loss coefficient of the solar collector and TES system has been made and compared with sensible TES system. An experimental data showed an augmented energy storage of 12% and 41% in “case 1” and “case 2” over sensible TES system as a result of reduction in heat losses with the cascaded arrangement of PCMs. The collector paired with case 2 configuration clearly exhibited a higher exergy efficiency due to supply of heat transfer fluid at relatively lower temperature while compared to other TES configurations. The outcomes of this study reveal the key role of cascaded arrangement of PCMs for enhancing energy and exergy efficiencies of solar collector.

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.