Purpose Of Energy Conservation Research Articles

Heat-confinement, water-resistance, and moisture-release electrospun membrane based on aerogel filler incorporation

The maintenance of a comparatively stable human body temperature through heating is essential for numerous physiological activities. However, the majority of the existing heating strategies are inefficient and wasteful in terms of energy usage, while also falling short in sufficiently protecting the human body against environmental hazards. Fabrics possessed the abilities to retain heat, repel water, and permit moisture to travel through are in high demand, which are essential for energy conservation and protective purposes. Herein, we introduce a highly efficient approach for producing electrospun membranes that exhibit excellent properties of heat confinement, water repellency, and moisture release properties, achieved by incorporating SiO2 aerogel fillers into interconnected nanofibers. As a result, the obtained aerogel filler incorporation membrane (AFIM) composed of PVDF@SiO2 exhibited a reduced thermal conductivity and reinforced moisture-release capability, leading to a 2 °C increase in temperature differential over its cotton counterpart and a water vapor transmission rate (WVTR) of 26.83 kg•m−2day−1. This work offers insights into the advancement of the thermoregulatory textiles to conserve energy and prevent waterlogging in future challenging conditions.

Bio-inspired micropatterned thermochromic hydrogel for concurrent smart solar transmission and rapid visible-light stealth at all-working temperatures

Thermochromic hydrogels exhibit a smart capacity for regulating solar spectrum transmission, enabling automatically change their transmissivity in response to the ambient temperature change. This has great importance for energy conservation purposes. Military and civilian emergency thermochromic applications require rapid visible-light stealth (VLS); however, concurrent smart solar transmission and rapid VLS is yet to be realized. Inspired by squid-skin, we propose a micropatterned thermochromic hydrogel (MTH) to realize the concurrent control of smart solar transmittance and rapid VLS at all-working temperatures. The MTH possesses two optical regulation mechanisms: optical property regulation and optical scattering, controlled by temperature and pressure, respectively. The introduced surface micropattern strategy can arbitrarily switch between normal and diffuse transmission, and the VLS response time is within 1 s compared with previous ~180 s. The MTH also has a high solar-transmission regulation range of 61%. Further, the MTH preparation method is scalable and cost-effective. This novel regulation mechanism opens a new pathway towards applications with multifunctional optical requirements.

The cores regulation of paraffin-chitosan phase change microcapsules for constant temperature building

Phase change materials (PCMs) can store and release latent heat under the designed phased change temperature and have received substantial interest for energy conservation and thermal control purposes. The use of PCMs in the construction of constant temperature buildings can improve the comfortable environment and save more energy. However, the leakage of PCMs during phase change process limits the application of PCMs. In this paper, a series of PCMs microcapsules with controllable core numbers is synthesized with paraffin (37 ℃) as the core and cross-linked chitosan as the wall. The single-core phase-change microcapsules (S−PCM) and multicore phase-change microcapsules (M−PCM) were prepared by adjusting the preparation condition. The latent heat of S−PCM and M−PCM are 61.4 mJ mg−1 and 50.1 mJ mg−1, respectively. The S-PCM and M−PCM display good stability without paraffin leakage. In addition, the composite blocks of gypsum and S−PCM (GSCM) and M−PCM (GMCM) were prepared and the thermoregulatory effection was investigated, where the surface temperature of GSCM was 5–10 ℃ lower than that of pure gypsum block. PCMs may also have broad application space in electronics, cold chain, and other industries.

A NOVEL ANALYTICAL SOLUTION OF MERKEL EQUATION FOR COUNTERFLOW COOLING TOWERS

Accurate performance analysis of direct-contact air-water counterflow cooling towers is important in practice for energy conservation and cost savings purposes. In general, accurate analysis can often be made using Merkel’s theory. However, a simple and accurate analytical solution of the Merkel equation is not yet available. In this paper, a novel and accurate analytical solution is presented, obtained from direct integration of the Merkel equation. The new method gives excellent agreement when compared with the use of standard Merkel’s method when predicting the outlet water temperatures with maximum root-mean-square error of 0.2% for a practical range of operating conditions. The new method also predicts the outlet water temperatures for four experimental cooling towers with maximum root-mean-square error of 0.8%. A limited validation shows that the method is also applicable to performance analysis of an actual crossflow cooling tower. The new method is a valuable addition to the existing methods of solving the Merkel equation.

On energy conservation for fixed-wing UAV assisted practical full-duplex relaying with service requirement and bank angle limit

This paper studies a full-duplex (FD) amplify-and-forward relaying, where a fixed-wing unmanned aerial vehicle (UAV) is dispatched as a mobile relay to serve a source-destination communication pair so as to satisfy their service requirement. Here, the UAV relay flies in a circular path and hence it must continuously change its heading of flight which leads to a bank angle of the aircraft. In order to ensure flight safety, therefore, a bank angle limit is imposed on the UAV relay. By considering a practical FD relaying, namely, there exists both residual loop interference (RLI) and processing time-delay at the relay side, novel signal to interference plus noise ratio (SINR) received at the destination is analyzed, giving a closed-form expression in addition to a concise lower-bound. Armed with the SINR analysis, the size of data received by the destination during a period of flight time of the UAV is calculated, leading to a closed-form lower-bound of the size of data. Taking bank angle limit into consideration and using the calculated lower-bound of the size of data, an optimization problem with the purpose of energy conservation is solved, leading to a novel method for joint adjustment of the UAV's flight parameters. Computer simulation experiments are conducted, and the results demonstrated that the proposed optimization method performs better in terms of energy conservation compared to the benchmark techniques regardless of the value of RLI and/or the service requirement of the source-destination communication pair.

Development of a Novel Energy Saving and Environmentally Friendly Starch via a Graft Copolymerization Strategy for Efficient Warp Sizing and Easy Removal.

Warp sizing is a key process in textile production. However, before the yarn/fabric finishing, such as dyeing, the paste adhering to the warp must be eliminated to ensure optimal dyeing properties and the flexibility of the fabric. Therefore, the sizing will often consume a lot of energy and produce a lot of industrial wastewater, which will cause serious harm to the environment. In this study, we have developed an energy saving and environmentally friendly starch-based slurry by modifying natural starch with acrylamide. The paste has excellent viscosity stability and fiber adhesion, and exhibits excellent performance during warp sizing. In addition, the slurry has good water solubility at 60-70 °C, so it is easy to desize at low temperatures. Because of this, the sizing of the warp can be deslimed directly from the yarn during subsequent washing processes. This work can not only reduce some costs for the textile industry, but also achieve the purpose of energy conservation and emission reduction.

Experimental study on solidification/stabilisation of high-salt sludge by alkali-activated GGBS and MSWI bottom ash cementitious materials

This study utilises alkali-activated ground granulated blast furnace slag (GGBS) as the primary method for solidification/stabilisation, with municipal solid waste incineration (MSWI) bottom ash (BA) as an auxiliary precursor to assist in the solidification/stabilisation (S/S) of high-salt sludge. The results show that the alkali-activated GGBS and MSWI BA cementitious material can effectively realize the S/S of high-salt sludge. However, having early strength of the alkali-activated GGBS solidified sludge at low GGBS content is difficult. In comparison, the addition of MSWI BA enhances the unconfined compressive strength (UCS) of the alkali-activated GGBS solidified sludge to reach 6.35 MPa at 3d curing age, whereas the UCS of the alkali-activated GGBS solidified sludge with 20% GGBS achieves only 0.31 MPa at 14d curing age. The MSWI BA significantly improves the effect of S/S on high-salt sludge by alkali-activated GGBS, and the solidified high-salt sludge with 20% alkali-activated GGBS and MSWI BA cementitious material exhibits good water stability, the UCS of which retain 2.33 MPa after 28d water immersion. The analysis of the mineral composition, chemical bond transformation, thermal stability and microstructure of the solidified sludge samples indicates that the geopolymer cementitious material generated by alkali-activated GGBS and MSWI BA can effectively cement and wrap sludge particles and soluble salts, and reduce the strength loss of the solidified samples after water immersion. Moreover, the addition of MSWI BA accelerates the polymerization of alkali-activated GGBS, leading to rapid solidification/stabilisation of high-salt sludge in early curing age and reduction of the consumption of mineral resources. The heavy metal leaching concentration of the solidified sludge is much lower than that of the raw MSWI BA, and can satisfy the pollution control standard limit of landfill. The immobilization efficiency of the heavy metals of the solidified sludge is larger than 89%. By using MSWI BA as an auxiliary precursor in alkali-activated GGBS, the co-disposal of high-salt sludge and MSWI BA can be achieved, providing insights for realizing the energy conservation and environment protection purposes of solid waste reclamation and GGBS consumption reduction.

Recycling of waste glass in lightweight geopolymer using incineration bottom ash as a foaming agent: Towards energy conservation

A large amount of waste glass and municipal solid waste incineration bottom ash (IBA) generated in municipalities is a serious environmental issue. For energy conservation purpose, this study aimed to develop a novel thermal insulating lightweight self-foaming geopolymer (SFG) material using waste glass as the main precursor and IBA as a foaming agent. The microstructure was investigated by XRD, FTIR, NMR, MIP and SEM-BSE techniques to reveal the mechanisms of the foaming process and geopolymerization reaction. The results showed that the use of 100% waste glass powder (WGP) as the precursor led to a connecting-cracked matrix due to silica gel shrinkage. However, the cracking was significantly alleviated when 50% IBA was incorporated as IBA contributed to more stable C-(N)-A-S-H (calcium silicate hydrate substituted with Al and Na) production as well as spherical pores formation to mitigate crack propagation. The SFG prepared with 50% IBA exhibited a geopolymer matrix with more regular and independent pores than that prepared with 100% IBA. This was because the high metallic Al content in IBA generated an excessive amount of hydrogen gas, resulting in the development of irregular and interconnected pores. Given the stability of the reaction products with fewer cracks and a uniform pore structure, the SFG prepared with 50% IBA and 50% WGP exhibited satisfactory functional properties (low density and thermal conductivity as well as desirable compressive strength), indicating a great potential for energy saving and environmental protection.

Applications of phase change materials in solar water heating systems: A review

The use of a phase change material for the storage of latent heat is an ideal approach for the storage of thermal energy due to the high thermal density of storage, the isothermal nature of the storage process, and the ease with which it may be controlled. In recent years, there has been a rise in the use of latent heat storage systems for the purpose of energy conservation, solar heating systems, and waste heat recovery systems. The use of solar water heaters in practical settings has become more widespread. After providing a summary of the information that has been disseminated on the theoretical uses of water heaters, this article begins by examining the research that has been conducted on the practical applications of solar water heaters. This article includes covers methods to improve the efficiency of these systems as well as research on solar water heaters that combine phase change material with solar water collectors. This paper concludes with several suggestions for further research on phase change material-based water heaters. The completion of this review in a fruitful manner leads to a greater comprehension of the research and development of phase change material-based water heaters as well as the many methods by which these heaters might be improved.

Insight on the sustainable design and multi-objective optimization for separating the ternary azeotropic mixture of toluene/n-butanol/water by natural decanting coupled with pressure swing distillation

The effective recovery of n-butanol (BuOH) and toluene from wastewater via sustainable separation process is critical to promote environmental protection and resource utilization. In this work, we propose a comprehensive methodology to develop a natural decanting coupled with pressure-swing distillation (NDPSD) for the azeotropic separation of BuOH/toluene/water system. Firstly, the thermodynamic topologic insights are employed to analyze the feasibility of the NDPSD. Secondly, conceptual design involving the understanding of mass balance lines, the liquid–liquid envelope, and distillation boundaries were applied to develop initial design of the NDPSD with two different separation sequences (i.e., configurations). Then, both initial designs are optimized to obtain the optimum column configurations via an improved non-sorting genetic algorithm, with the total capital and operating cost as dual objective function. Finally, both optimized schemes are heat-integrated for the purpose of energy conservation. The performance of all the developed configurations were examined using three indicators, i.e., economic, environmental, and energy efficiency, and our results revealed that the heat-integrated configuration B with separation sequence of water → BuOH → toluene provides the best economic, environmental, and thermodynamic efficiency.

A Self-Powered Energy-Saving Epidemic Prevention Tent

The current situation of the epidemic is complex and changeable. Under the China adherence to the “dynamic zero clearance,” epidemic prevention and control is closely related to all walks of life, and epidemic prevention awning has become one of the essential basic epidemic prevention facilities. However, most of the epidemic awnings are manufactured for the isolation and protection from wind and rain, which could not meet the needs of electricity allocation during emergencies. Therefore, our goal is to design a new energy-saving epidemic prevention tent that is green, stable, and easy to shrink. It is equipped with multiple energy storage and multivariate methods to achieve self-supply of electric energy. First the “1+1” arrangement design of solar power panels on the anti-epidemic tent and pressure power panels combined with the design of pressure power panels under the tent can receive various energy inputs. At the same time, retractable brackets are designed under the four pillars, which are easy to fold and enhance the stability of the canopy. The utilization of energy is more diversified to achieve the purpose of energy conservation and emission reduction. Its market value is broad, and the development prospect is good.

A Mine Ventilation System Energy Saving Technique Based on an Improved Equilibrium Optimizer

Over the years, the ventilation systems used in coal mines have become more and more complex. Due to a lack of scientific and effective management, the energy consumed by ventilation systems has rapidly increased, resulting in considerable wasted energy. To solve this problem, the authors established a nonlinear optimization model aimed at minimizing the total energy consumption of a mine ventilation network. Furthermore, the authors propose an improved equilibrium optimizer algorithm to solve the model. First, the population is initialized by a chaotic map. Second, the adjustment strategy of a trigonometric function is introduced to improve the index F, which improves the global development ability of the algorithm, avoids falling into local optimum, and can improve the local search ability in the later stages. Then, Gaussian disturbance is introduced to enhance the diversity of particles and avoid falling into the local optimum. Finally, a learning factor was introduced to improve the generation rate G and improve the algorithm’s integrity; it was then compared with other algorithms. The simulation results show that the performance of the improved algorithm is significantly better than other algorithms. It was tested with the ventilation system of Wangjialing mine of Zhongmei Huajin Energy Co., Ltd. The results showed that the energy consumption of the ventilation system was reduced by 17.83%. This method can save the mine about 2 million yuan RMB every year. The economic effect is remarkable, we achieved the purpose of energy conservation and emission reduction, and the effectiveness of the proposed method was verified.

Enhanced thermal performance of Na2HPO4·12H2O composite phase change material supported by sepiolite fiber for floor radiant heating system

The application of phase change materials (PCMs) with latent heat storage characteristics in building system can coordinate the imbalance between energy supply and demand by absorbing excess heat, thereby achieving the overall energy consumption reduction. In this study, a novel kind of composite PCM (CPCM) composed of modified Na2HPO4·12H2O and sepiolite fiber (SEP) is developed. It is shown that adding 4 wt% of α-Al2O3 and 1.5 wt% of sodium alginate (SA) can reduce the supercooling degree of Na2HPO4·12H2O from 18.4 °C to 1.0 °C. The obtained PCM mixture is absorbed into SEP to fabricate form-stable composite PCM at a loading of 60 wt%, which has a melting temperature of 35.7 °C and a high latent heat of 127.8 kJ kg−1. The composite processes good thermal reliability and a moderate thermal conductivity of 1.069 W m−1 K−1. Furthermore, thermal performance of the CPCM is evaluated by combining a floor radiant heating system with CPCM layer in a small testing room. It is found that the average central temperature of the testing room with CPCM floor can be increased by 3.1 °C compared to that of the reference room. Besides, the thermal comfort time of indoor air temperature in CPCM room can be up to 252.5 min longer. The better thermal regulation performance of the CPCM floor is attributed to its suitable phase change temperature and high latent heat. The results indicate that the obtained CPCM can be employed into floor system for building energy conservation purpose.

Study on catalytic decomposition of vehicle exhaust pavement materials by TiO2

To achieve low-carbon development and reduce greenhouse gas emissions, it is urgent to solve the problem of automobile exhaust emissions. The photocatalytic material nano titanium dioxide is applied to asphalt pavement to realize the catalytic decomposition of automobile exhaust gas, and achieve the purpose of energy conservation, emission reduction, and environmental protection. In this paper, the photocatalytic efficiency of tail gas degradation of TiO2 thin layer asphalt mixture and TiO2 micro surface asphalt mixture was studied, and the influence of different light intensity on the photocatalytic efficiency of tail gas degradation of the mixture was analyzed. The results show that, with the increase of TiO2 content in the mixture, the tail gas degradation efficiency of the TiO2 thin layer and TiO2 micro surface type mixture increases at first and then becomes stable. In the TiO2 thin layer mixture, when the content of TiO2 reaches 90% (accounting for the mass of ore powder), the cumulative decomposition rates of NO, HC and CO are 43.8%, 19.5%, and 26.1%, respectively, under outdoor natural light. Under ultraviolet light, the cumulative decomposition rates of NO, HC, and CO were 50.6%, 25.12% , and 29.33%, respectively. In the TiO2 microsurface type mixture, when the content of TiO2 reaches 75%(accounting for the mass of ore powder), the cumulative decomposition rates of NO, HC, and CO are 49%, 24.3%, and 26%, respectively, under outdoor natural light. Under ultraviolet light, the cumulative decomposition rates of NO, HC, and CO were 53.9%, 27.6%, and 29.8% respectively. Therefore, compared with outdoor natural light, the asphalt mixture with the same TiO2 content has a higher cumulative decomposition rate of NO, HC, and CO under ULTRAVIOLET light. Under the same experimental conditions, the utilization efficiency of TiO2 microsurface type mixture for TiO2 photocatalyst is better than that of TiO2 thin layer type mixture. Considering the degradation effect of tail gas and the utilization efficiency of TiO2 photocatalyst, the optimal TiO2 content of thin layer mixture is 60% (accounting for the mass of ore powder), and that of micro surface type mixture is 50% (accounting for the mass of ore powder).

Energy-saving design and control strategy towards modern sustainable greenhouse: A review

A greenhouse is an energy-intensive sector with substantial greenhouse gas emissions and extensive energy consumption. Energy-saving greenhouse strategies become particularly important on the premise of ensuring effective crop production to achieve sustainable energy development. This paper aims to deliver a comprehensive review on crucial energy-saving strategies from greenhouse design to operational stage. This contribution analyses effective energy-saving methods for greenhouse design considering greenhouse structures, ventilation and lighting systems. It details the energy-saving operation of greenhouses by summarising renewable energy technologies and integration systems, including photovoltaic modules, solar collectors, heat pumps and other integrated modules. These environment-friendly technologies achieve the purpose of environment protection and energy conservation of greenhouse. The research findings reveal that more than half of the energy is saved through appropriate greenhouse renovation. Control strategies for improving the energy efficiency of the greenhouse in aspects of monitoring system management and control algorithms have been discussed as well. The neural network combined with other control algorithms is a suitable approach to solve nonlinear control problems with a good control accuracy. In the final part, the life cycle environmental impacts and environmental footprints assessment of greenhouse is discussed. Life cycle assessment of modern integrated greenhouse is expected to be further studied. This review provides valuable insights and suggestions for the design and transformation of modern sustainable greenhouses.

A Population-Based Iterated Greedy Algorithm for Maximizing Sensor Network Lifetime.

Finding dominating sets in graphs is very important in the context of numerous real-world applications, especially in the area of wireless sensor networks. This is because network lifetime in wireless sensor networks can be prolonged by assigning sensors to disjoint dominating node sets. The nodes of these sets are then used by a sleep–wake cycling mechanism in a sequential way; that is, at any moment in time, only the nodes from exactly one of these sets are switched on while the others are switched off. This paper presents a population-based iterated greedy algorithm for solving a weighted version of the maximum disjoint dominating sets problem for energy conservation purposes in wireless sensor networks. Our approach is compared to the ILP solver, CPLEX, which is an existing local search technique, and to our earlier greedy algorithm. This is performed through its application to 640 random graphs from the literature and to 300 newly generated random geometric graphs. The results show that our algorithm significantly outperforms the competitors.

Economic Benefit Evaluation System of Green Building Energy Saving Building Technology Based on Entropy Weight Method

The development of the construction industry has brought great convenience to people’s lives, but the problems of resource shortages and energy consumption are becoming more and more serious. In order to solve the problem of resource shortages and energy consumption, this paper puts forward an evaluation system of technical and economic benefits of green building energy conservation based on the analytic hierarchy process and entropy weight method. In view of the correlation between building technology and economic benefits, this paper puts forward the economic benefit evaluation system of green building energy-saving technology combined with analytic hierarchy process and entropy weight methods, determines 6 first-class evaluation indexes and 20 s-class evaluation indexes, and takes the dynamic incremental investment payback period and incremental economic benefit ratio as the evaluation indexes, and finally obtains the economic benefit score and star value of green building. Combined with the actual situation of a middle school project, the incremental economic benefits of the four green technologies in energy conservation and resource utilization indicators are 44,256.75 yuan, 1,015,924.2 yuan, 255,490 yuan and 32,871.57 yuan, respectively. The total incremental economic effect and unit incremental effect of the six evaluation indicators are 1,472,113.3 yuan and 1501.99 yuan/m2 respectively. The economic effect of energy-saving and renewable resource utilization technology is the largest. The total score of the project is 0.404902 and it has three stars. Compared with traditional building technology, the application of green building technology and related facilities and equipment proposed in this paper can greatly reduce the consumption of building resources, so as to achieve the purpose of energy conservation and emissions reduction. This method combines objective evaluation with subjective evaluation, complements fair objective evaluation and expert evaluation, makes the best use of all basic information, and ensures the scientific effectiveness of the comprehensive evaluation model.

Study on photothermal properties of Zn-ZnO/paraffin binary nanofluids as a filler for double glazing unit

Binary nanoparticles may effectively improve photothermal properties of the phase change material (PCM) to expand its application in solar energy, especially in energy-saving window. In the present work, various Zn-ZnO/paraffin binary nanofluids with different concentration and Zn:ZnO ratio are prepared for researching the paraffin photothermal properties enhancement by Zn-ZnO binary nanoparticles, and the applicability of Zn-ZnO/paraffin nanofluids as a filler for double glazing unit is discussed. The results show that: under the same ratio of Zn:ZnO(5:5), 0.001% volume fraction Zn-ZnO/paraffin binary nanofluids gives the largest photothermal conversion efficient ηof 18.1%, and the sample with 0.001% volume fraction, 8:2 ratio has superior conversion ability because of its lower solar absorption fraction (Am=35.1%) and higher conversion efficient(η=18.3%). By simulation of photothermal performance of double glazing unit, 0.001% nanoparticles volume fraction, 8:2 ratio Zn-ZnO/paraffin binary nanofluids as a filler for double glazing unit gives more comfortable indoor environment, reduces the utilization of electrical appliances, so as to achieve the purpose of building energy conservation, furthermore the best thickness of filler layer for target city is 6cm.

Recent advancements in latent heat phase change materials and their applications for thermal energy storage and buildings: A state of the art review

Phase change materials (PCMs) have received substantial interest for their ability to store and release latent heat for energy conservation and thermal control purposes. PCMs are available in a variety of latent heat and melting points but their performance is low due to low value of thermal conductivity which limits its usage. The addition of highly thermal conductivity nanoparticles, porous metal foams and encapsulation methods have been used to address this issue and try to fix the low thermal conductivity of PCMs which is broadly discussed in this manuscript. The ability of PCM to store and release the thermal energy prompted the researchers to use it in potential applications. The energy retained and emitted by PCMs may be used for a variety of purposes, such as in photovoltaic (PV) panels, thermoelectric generators, building air-conditioning, air and water heating systems, heat exchangers, desalination solar stills, textiles, thermal management of electronic equipment and batteries and food packaging. Therefore, in this review, first the advancements in thermal properties of PCMs are thoroughly discussed in terms of enhancement in melting and solidification rates. After that, the use of PCMs in various applications is then explored, and conclusions are drawn accordingly. Based on analysis of recent literature, it was discovered that the phase transition temperature, phase transition enthalpy and thermal conductivity are three important parameters for the selection of an appropriate PCM for use in various applications. The current status of these advanced energy storage materials is also presented in this review. Lastly, some challenges and future recommendation are also proposed for future researchers which will bring a revolution in thermal management field.

Design of intelligent kitchen waste sorting machine based on Pro/E and Adams

In order to effectively solve the problem that the subsequent waste treatment is affected by foreign bodies such as bones and hard shells in kitchen waste, reduce the treatment cost and improve the utilization efficiency of kitchen waste, this paper designs a small kitchen waste Intelligent Classification Recycling and reprocessing device which can be applied to school canteens, communities and township waste treatment plants. The device is mainly composed of mechanical body, central processing unit, detection and sensing system and post-processing system design. It can further separate kitchen waste on the basis of solid-liquid separation, realize reprocessing and recycling, and maximize the recycling value of kitchen waste, so as to achieve the purpose of energy conservation, emission reduction and sustainable development.