Abstract In this study, the improvement efficiency of the thermochromic coating was analyzed comprehensively on the thermal performance of exterior walls by regulating solar radiation absorptivity in the hot-summer and cold-winter zone. The heat transfer model with the dynamic radiation absorptivity was built by The ANSYS 16.0 software, while the heat transfer process of the exterior wall was simulated numerically in the whole year. Numerical results showed the thermochromic coating exerted the regulation ability on the solar radiation absorptivity with 80% to enhance the heat gain during winter and 20% to dampen the heat gain during summer. Due to the regulation ability of the thermochromic coating, the maximum and average temperatures in outer surfaces were increased by 1.68°C~6.96°C and 1.24°C~1.92°C in winter, while they were lowered by 13.10°C~13.45°C and 3.09°C~4.42°C in summer. The load reduction efficiency of the thermochromic coating was the most obvious in summer, followed by winter and the worst in the transition season. In the transition season, the thermochromic coating had the small benefit and even the negative effect on the wall thermal performance. From the view of the whole year, the cooling and heating loads were reduced by 10.93% and 16.36%, respectively, due to employing the thermochromic coating.

Abstract Windows are the communication medium between indoor and outdoor, but their influence and the corresponding landscape outside the window are often ignored due to the outdoor frequent activities of people. The coronavirus disease 2019 (COVID-19) has been a better choice to show the window performance, especially for the anxiety level alleviation of people isolated at home. A national survey was conducted on the anxiety of self-separation people and the window influence. The results showed that the average anxiety level was 1.54, between a little anxious and anxious, due to the COVID-19. The best satisfaction with the landscape outside the window was waterscape (2.98), followed by green plants (2.33) and buildings (0.83). During the COVID-19, the average number of overlook times increased by 1.49 times/day, which is higher 0.42 ties/day than the normal condition. The landscape types had the certain influence on the overlook frequency, the window opening times and even the anxiety level. The average anxiety levels are 1.36 and 1.68 with natural landscapes and human landscapes, respectively. Optimizing the landscapes outside the window plays an important role in alleviating the anxiety of residents and improving their mental health.

Abstract The future development of the world is threatened due to global warming and climate change mainly driven by carbon emissions. Conducting an extensive study on the influencing factors of regional energy consumption and prediction through scenario simulation is of great significance for China in order to meet its aim of achieving carbon peak by 2030. The affected areas of the lower Yellow River are one of the main grain-producing areas in China, and it is facing a strong demand for urbanization and rapid economic development. Based on the night light data, This study demonstrates that the carbon emissions from energy consumption in the study area showed an upward trend from 2000 to 2018 with obvious spatial distribution differences. Economic development had a significant positive effect on the increase in carbon emissions from energy consumption; energy consumption intensity showed a significant negative effect. The study area achieves the carbon peak target in 2027 only under the low-carbon scenario. This study is helpful to realize ecological protection and high-quality development in the Yellow River Basin, and also has reference significance for other developing countries.

AbstractLandfilling is the most commonly used option for waste disposal in China but occupies massive land resources and solar landfills could be a win-win solution by installing photovoltaic (PV) systems on the closed landfills. This paper theoretically studies the feasibility of solar landfills and compares two possible PV technologies, which are polycrystalline silicon (p-Si) and thin film PVs, from the aspects of energy and financial performance. Based on the research, the capacity factors of p-Si and thin film PV are 19.706% and 17.825%, while the conversion efficiency of them are 12.52% and 10.05%, respectively. The financial analysis indicates that the discounted payback period of p-Si PV is 13.42 years while that of thin film PV is 18.56 years. From another aspect, the levelized cost of electricities of p-Si and thin film PV are 0.87 and 0.92 CNY. The conclusion that can be drawn from the above research is that solar landfills are feasible for the case in Qingyuan energetic and financially. Compared with the thin film PV, the p-Si PV is the optimal choice for solar landfills no matter from the aspects of performance or financial consideration.

Abstract This paper reports on the investigation of the gasification from biomass using a laboratory scale fluidized bed gasifier. Main influencing factors, such as the temperature, steam flow rate and CaO to biomass mass ratio were studied. A model was developed for hydrogen-rich gas production from biomass via using ASPEN PLUS software. Sawdust was used as raw material for this study. Different operating conditions were considered and the model was verified. The results showed that the production of H2 and CO2 increased while the production of CO and CH4 decreased with increasing temperature. When the steam was used as the gasifying agent at different temperatures, the production of H2 increased significantly and its growth rate was ~48%. The increase of CaO to biomass mass ratio from 0% to 50% resulted in hydrogen content increasing from 40% to 68%. Simulation results showed that the model was suitable for biomass gasification process, which could provide some reference value for further biomass gasification experiment.

Abstract The concerns regarding the consumption of traditional fuels such as oil and coal have driven the proposals for several cleaner alternatives in recent years. Hydrogen energy is one of the most attractive alternatives for the currently used fossil fuels with several superiorities, such as zero-emission and high energy content. Hydrogen has numerous advantages compared to conventional fuels and, as such, has been employed in gas turbines (GTs) in recent years. The main benefit of using hydrogen in power generation with the GT is the considerably lower emission of greenhouse gases. The performance of the GTs using hydrogen as a fuel is influenced by several factors, including the performance of the components, the operating condition, ambient condition, etc. These factors have been investigated by several scholars and scientists in this field. In this article, studies on hydrogen-fired GTs are reviewed and their results are discussed. Furthermore, some recommendations are proposed for the upcoming works in this field.

Abstract Photovoltaics have the advantages of being clean and renewable and have gained a wide range of applications. It is promising to use photovoltaic energy for the power supply of buildings, as the building sector accounts for a large portion of global energy consumption with a constantly increasing trend. However, photovoltaics are greatly affected by time and environment, and it is usually combined with batteries to form a photovoltaic–battery energy storage system to meet the load demand. This paper aims to analyze and compare energy management strategies of an on-grid solar photovoltaic–battery system for a real building project in a typical May and October region, but unlike other studies, the strategies used in this paper are very simple and easy to implement. It can also realize photovoltaic, battery and grid to meet the load power demand. Two strategies are used in this paper. Strategy 1 is to maximize the utilization of the energy generated by photovoltaics: while the energy generated by photovoltaics cannot meet the load demand, the battery will provide energy, and while the battery cannot meet the load demand, the grid will provide energy. The photovoltaic energy is given priority to the battery under the premise of meeting the load demand. Strategy 2 is to use the time-of-use electricity price, and the battery obtains cheap electricity at night to meet the load of the high electricity price the next day. The feasibility of the strategy used is demonstrated by actual data of buildings and photovoltaic–battery energy storage systems. This study can provide theoretical references for the energy management and system operation to facility managers and building occupants.

Abstract Analyzation the dynamics of biodiversity, carbon storage and environmental factors of coniferous forest in Loudi, Hunan Province is meaningful, determination the aboveground and underground carbon storage, plant diversity and environmental factors of multiple plant communities in Loudi, Hunan Province among different succession stage are of great significance to effectively clarify the distribution of plant diversity and carbon storage in coniferous forests along the succession gradient, clarify the influence of environmental factors on carbon storage, and quantify the relationship between carbon storage and plant diversity. This article selected the natural growth of subalpine coniferous forest in Loudi of Hunan province from 5 ~ 60 years as the research object, compared the species richness (S), plant diversity (S), and other information. The results showed that the carbon pools of aboveground and underground ecosystems of several plant communities are significantly different during vegetation restoration, and there is a functional relationship between plant diversity and carbon storage. The aboveground carbon content increased several times, and the soil organic carbon (SOC) content increased from the herbaceous community type to the mixed forest type, constituting the main carbon pool of the system (63%—89%), and then decreased. The average carbon storage of the whole ecosystem was between 105–730 Mg C ha−1. In addition, it was also found that root biomass and litter C/N ratio had significant effects on soil organic carbon. Path analysis also showed that the C/N ratio of litter mainly regulated by the changes of microbial population and soil invertase activity. The research of this project is of positive significance to deepen the understanding of coniferous forest biodiversity and corresponding conservation measures.

Abstract In recent years, non-thermal plasma technology has gained considerable attention. It can produce highly reactive hydroxyl radicals and other strong oxidants, which is promising in environment pollutants removal. This article mainly reviews the recent advances in environment contaminants removal with several well-known non-thermal plasma technologies. We first introduce non-thermal plasma technology and its development, then summarize their applications for air purification organic wastewater treatment and sludge organic crack and prospect their further development in the future.

AbstractIn this paper, medium temperature chiller with induction air-conditioning system is introduced. Several onsite measurements were carried out on temperature & relative humidity distribution and energy consumption in summer 2020 in order to study the potential performance when applied in hot summer cold winter zone. The performance test results show that (1) the indoor temperature and humidity both comply with the range of design parameters; (2) the corresponding indoor air dew point temperature is much lower than the supply air temperature of air inductive unit, which implies no condensed water or dew on surface of air inductive unit; (3) the performance of the circulation pump, extensive type air handling unit fan and medium temperature chiller has exceeded the requirements of national standards.

AbstractA renewable energy source, especially solar energy, is one of the best alternatives for power generation in rural areas. Organic Rankine cycle (ORC) can be powered by a low-grade energy source, suitable for small-scale power production in rural areas. This study investigates the combined power generation and cooling system using the combination of ORC and vapor compression cycle (VCC), where ORC is powered by a parabolic trough solar collector. Thermodynamic and economic simulation of the system is conducted for four different working fluids, which are R245fa, R114, R600 and R142b. It can be concluded that the thermal efficiency of the power plant increases by using the combined ORC-VCC system. The effect of thermodynamic parameters such as turbine inlet temperature and pressure on the system performance is also discussed, and the optimal design values are provided. The results show that the power plant uses R245fa as the minimum exergy destruction rate. The study indicates that R114 gives minimum cost function (PCEU) for 137°C turbine inlet temperature while the minimum PCEU for R142b is obtained at a turbine inlet pressure of 2500 kPa. Finally, the study indicates that the inlet pressure of the turbine has a significant impact on the system cost and thermal efficiency.

AbstractReducing cooling loads in hot countries requires thermal insulation, and cooling methods be improved. Evaporative cooling, although problematic, is one solution that can be explored since it is significantly more efficient than regular compressor air conditioners, and the net result of using one is cooling. Furthermore, while compressor air conditioner efficiency decreases with rising temperatures in summer, evaporative ones, up to a point, are the exact opposite. A novel hybrid cooling system capable of combining both showed an 80% decrease in cooling load. The system’s efficacy was assessed in this paper by thermally simulating designs that are suitable for the hot Middle East region. Two locations with different environments and building guidelines that are representative of the variations in the area were selected. The first was the hot, dry Baghdad environment; the other was Dubai’s coastal, more humid city. Two different houses were designed to suit the municipal rules of each and accommodate the hybrid cooling system. As expected, the simulation results showed that savings in the dry Baghdad climate were high at 78% compared to a non-insulated alternative. In Dubai, unsurprisingly, they were less at 52% on the more humid coast. Further simulations revealed that this latter figure in the humid coast could also be achieved using good thermal insulation.

AbstractAs an important non-metallic mineral resource, zeolite is widely used in many fields. In this paper, natural zeolite from Chifeng, Inner Mongolia, was selected as the experimental material, and the calcination effect of the sample was studied in detail. The zeolite sample undergoes complex changes during the calcination process. The higher the calcination temperature, the smaller the specific surface area of the sample. When calcined at 150 °C for 1 hour, zeolite samples with granularity ranging from 0.050 to 0.075 mm shows relatively good removal of Cu2+ and Pb2+from aqueous solution. After the zeolite is calcined, the solution with an initial concentration of 100 mg/L of heavy metal ions can reduce the concentration of Pb2+ and Cu2+ to 25 mg/L and 60 mg/L respectively, with a removal rate of 75% and 40%. In addition, this article also focuses on its removal mechanism.

AbstractPolypropylene (PP) has the most extensive plastics of plastics because of the advantages of simplicity, easy processing, high mechanical properties, high corrosion resistance and abrasion resistance and electrical insulation. The application of PP has limitations in many fields because it is lack of formation shrinkage, low modulus, poor thermal stability, strong gap and low temperature and cracking. The addition of mineral fillers can not only improve their performance, not just the PP/mineral filler composite materials required, but also reduce the cost of the material. Therefore, in this paper, lamellar mica was selected as mineral filler to modify the surface of PP. The effects of titanate coupling agent and silane coupling agent modified mica, and their addition on the properties of PP were systematically studied. KH-570 modification increases the tensile strength, bending strength and modulus of the composites, while JN-114 and KH-570 can effectively improve the toughness and processability of PP composites. The interaction between modifier and mica was analyzed comprehensively by infrared spectroscopy (FTIR), and the effect mechanism of mica on the properties of PP was discussed by scanning electron microscope. The results show that different modified mica as mineral filler and PP can produce synergistic effect.

AbstractThe utilization of photovoltaic (PV) cells has greatly expanded due to the simplicity of technology and cheapness compared to other solar technologies. However, due to the change in the position of the sun, it has reduced the production capacity and electrical efficiency of this technology as the reduction of production capacity to supply electricity has increased investment costs. In this research, modeling of silicon crystal PV cell with the aim of influencing the types of solar trackers on the amount of power produced by PV cell and economic parameters has been done, which is intended for the following four modes: without solar tracker, horizontal tracker, vertical tracker and two-axes tracker. The highest output power is related to the two-axes tracker with a value of 9586 kWh/yr, which for this technology has a maximum output power of 4.35 kW. Also, the cost of energy produced by this technology is $ 0.875/kWh.

AbstractSolar power has become one of the most essential sources in the move to clean energy production. It plays a vital role in providing environmental, social and economic benefits. As a result, the solar panels must be cleaned consistently. There are several cleaning methods, including passive, active and manual cleaning. In this paper, multi-criteria decision making (MCDM) method Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is utilized to compare between different cleaning methods and find the optimal cleaning method in Dubai. This approach considers the influential factors and their relative importance of the cleaning methods to prioritize the alternatives. The aim of the work is to consider social, economic, and environmental criteria while choosing the appropriate cleaning method for solar PV panels. The chosen attributes include several important factors, such as initial and running cost, time required for cleaning, safety, energy required, water consumption, environmental impact and economic impact. Data was collected through a survey of solar energy experts in Dubai. Different weighting methods, such as Simple Additive Weighting (SAW) and Multiplicative Exponential Weighting (MEW) were used to determine the relative relevance of the criteria. Sensitivity analysis was conducted, and cost attribute was removed. CRITIC, entropy, and stochastic dominance (SD) were calculated, and the results revealed that robot water based (sprinkler and brush) cleaning method was the most effective option 0.648, 0.753,0.707, respectively. Also the sensitivity analysis results confirmed that robot water based is the most preferred cleaning method by experts in Dubai.

Abstract Demand forecasting is an essential stage in the plan and management of resources for water and electrical utilities. With the emerging of the concept of water–energy nexus and the dependence of both resources on each other, intelligent approaches are needed for such resources’ prediction in smart communities. Over the past few decades, extensive research has been devoted to develop or improve forecasting techniques to accurately estimate the future demand. The purpose of this paper is to review the most important methods in the demand forecasting of both water and energy, focusing mainly on the most recent advancements and future possible trends, hence providing a guide and insight for future research in the field. With the recent developments in artificial intelligence, it has been observed that most research work in this area highlight the artificial intelligence–based models as promising approaches for short-term demand forecasting in terms of performance evaluation or improvement in accuracy. Finally, all metrics used by researchers to assess the water/energy demand forecast are gathered and compared to provide a solid ground for the future works.

Abstract This study aims to evaluate the performance of a flat plate solar water heater (SWH) theoretically and experimentally. The thermal performance of the SWH was predicted using Fortran 90 programming language. SWH was designed as a square shape with dimensions of 110 cm length, 120 cm width and 10 cm depth and tested by integrating with a modified solar distiller to increase the water temperature in the basin at a constant mass flow rate of 1.2 l/min. The tests were conducted under the weather condition of Yekaterinburg city, Russia, from June to September of 2019, and a typical day was chosen for each month (19 June, 17 July, 22 August and 15 September). The study revealed that the highest efficiency of the solar water collector obtained at the highest value of the intensity of solar radiation at mid-day. The maximum thermal efficiencies achieved on 17 July of 2019 were ~67% and 66% based on theoretical and experimental analyses, respectively. A simultaneous increase in the water temperature and the intensity of solar radiation has been observed. During the four typical days of the experiment, the highest water temperatures of the solar collector were recorded during midday, i.e. $57.2{}^{\circ}\mathrm{C},64.4{}^{\circ}\mathrm{C},52.4{}^{\circ}\mathrm{C}\kern0.5em \mathrm{and}\ 49{}^{\circ}\mathrm{C}$ at the inlet, and $62.8{}^{\circ}\mathrm{C},71{}^{\circ}\mathrm{C},57.4{}^{\circ}\mathrm{C}$ and $53.2{}^{\circ}\mathrm{C}$ at the outlet for 19 June, 17 July, 22 August and 15 September 2019, respectively, while the solar radiation intensities recorded are $957,1022,840\kern0.5em \mathrm{and}\ 723\ \mathrm{W}/{\mathrm{m}}^2$ for the test days.

ABSTRACTSolar energy is deemed as the most abundant, reliable, eco-friendly and totally free resource of energy. There is a wide range of techniques to harness solar energy for different purposes. Among all the available methods, direct conversion of sunlight into electricity through photovoltaic (PV) phenomenon is the most mature and popular process. Progress of PV technology in market is perspicuous; however, it has still some drawbacks such as notable land requirement in cities, energy conversion efficiencies that already reached the theoretical limits and social acceptance issues due to aesthetic details. To overcome the aforesaid challenges, solar PV tree concept has been recently developed, and the simplicity, compact structure and elegance of this novel technology have been in the focus of researchers. Within the scope of this review, the concept of solar PV tree has been extensively investigated in terms of various design aspects and potential applications. Current performance characteristics of solar PV tree systems and power management strategies in real applications have been discussed. Challenges involved with the solar PV tree technology have also been addressed as well as suggestions on the direction of further works.

Abstract The potential of using ashcrete to improve the microstructural, microspectral and shrinkage properties of expansive soils has been investigated under laboratory conditions. In addition to microstructural, three chemical modulus (TCM) and microspectral examinations, responses to linear shrinkage, volumetric shrinkage and crack width were also investigated using 30-day drying periods for expansive soil treated with ash cement. Moisture-related infrastructures such as the sub-floor of resilient pavements are prone to moisture by the rise and fall of the water table during seasonal changes. Therefore, the effect of soil improvement on soil morphology, chemical content and microspectral patterns was investigated. The soil was classified and characterized as (A-7-6) high plasticity soil and poor classification conditions. The hybrid sawdust ash (SDA) known as ashcrete, which has zero carbon footprint was obtained by activating SDA by mixing it with a reformulated activator material (a mixture of 8 M NaOH and a solution of NaSiO2 in a 1:1 ratio). The zero carbon cement was further used in percent-by-weight proportions of 3, 6, 9 and 12 for the soil improvement. X-ray fluorescence (XRF) and scanning electron microscopy (SEM) experiments were carried out to evaluate the pozzolanic resistance via the chemical composition of the oxide, TCM and the profile of the surface contour of the additives and the soil. XRF exposures revealed that the additives had lower pozzolanic resistance, which increased with the improved mixtures thus forming an improved soil mass. In addition, it showed that TCM silica moduli dominated soil stabilization with ashcrete. Scanning electron microscopy examination showed an increase in soil-ettringite and gel formation with the addition of ashcrete. Also, the microspectral studies of chemical oxide EDXRF and XRD have shown excellent results at 12 mass percent cement and soil cement, which has optimized aluminosilicate formation more than 70% and formation of calcite and quartz that has shown the potential of a zero carbon stabilization geomaterial ash cement as a good complementary binder.