Theoretical Comparative Energy Efficiency Analysis of Dual Axis Solar Tracking Systems

This paper developed a theoretical model substantially based on the principle that only the normal component of solar radiation is actually converted into electrical energy. This theoretical model helped to predict minimum and maximum daily energy gain (compared to static PV system tilted with certain angle) when using dual axis PV solar tracking systems, at any given location on earth without prior experimental data. Based on equations derived from model, minimum and maximum energy gain is computed and summarized in tables of minimum and maximum. Furthermore, the model equations could be used to set up future experimental studies related to the matter.

Country-level meteorological parameters for building energy efficiency in China

Accurate basic data are necessary to support performance-based design for achieving carbon peak and carbon neutral targets in the building sector.Meteorological parameters are the prerequisites of building thermal engineering design,heating ventilation and air conditioning design,and energy consumption simulations.Focusing on the key issues such as low spatial coverage and the lack of daily or higher time resolution data,daily and hourly models of the surface meteorological data and solar radiation were established and evaluated.Surface meteorological data and solar radiation data were generated for 1019 cities and towns in China from 1988 to 2017.The data were carefully compared,and the accuracy was proved to be high.All the meteorological parameters can be assessed in the building sector via a sharing platform.Then,country-level meteorological parameters were developed for energy-efficient building assessment in China,based on actual meteorological data in the present study.This set of meteorological parameters may facilitate engineering applications as well as allowing the updating and expansion of relevant building energy efficiency standards.The study was supported by the National Science and Technology Major Project of China during the 13th Five-Year Plan Period,named Fundamental parameters on building energy efficiency in China,comprising of 15 top-ranking universities and institutions in China.

Passive Study of Energy Efficiency of a Building with PCM on the Roof during Summer in Casablanca

Energy efficiency in buildings is today a prime objective for energy policy at national and international levels. Because the residential and commercial energy consumption has steadily increased reaching figures between 20% and 40%. The use of thermal insulation of the building envelope is one of the most currently requested solutions to reduce this energy consumption. Phase Change Materials (PCM) have received increased attention due to their ability to store large amounts of thermal energy within narrow temperature ranges. This property makes them ideal for storage of passive heat in the building envelopes. An experimental study was conducted to analyze the influence of PCM in the construction of exterior walls. Two test cells are constructed in the Faculty of Science Ain Chock, Casablanca. One is equipped with a 0.56 cm layer of PCM on its roof while the second is a reference cell without PCM. The results presented for the period from 8th to 10th July 2014 show that the integration of PCM layer reduces the amplitude of instantaneous heat flux through the horizontal wall. The indoor and the internal vertical wall temperatures, in the case of the cell with PCM, are relatively decreased compared to those of the reference one. For example, the maximum deviation between the indoor temperatures of the cubicles is not more than 1.5℃ while the one on the west faces reaches 3℃ by mid day. Also the inclusion of a layer of PCM shifts the time of peak load and discharge.

Sensitivity of Solar Photovoltaic Panel Efficiency to Weather and Dust over West Africa: Comparative Experimental Study between Niamey (Niger) and Abidjan (Côte d’Ivoire)

Energy demand is increasing while we are facing a depletion of fossils fuels, the main source of energy production in the world. These last years, photovoltaic (PV) system technologies are growing rapidly among alternative sources of energy to contribute to mitigation of climate change. However, PV system efficiency researches operating under West African weather conditions are nascent. The first objective of this study is to investigate the sensitivity of common monocrystalline PV efficiency to local meteorological parameters (temperature, humidity, solar radiation) in two contrasted cities over West Africa: Niamey (Niger) in a Sahelian arid area and Abidjan (Cote d’Ivoire) in atropical humid area. The second objective is to quantify the effect of dust accumulation on PV efficiency in Niamey (Niger). The preliminary results show that PV efficiency is more sensitive to high temperature change especially under Niamey climate conditions (warmer than Abidjan) where high ambient temperatures above 33°C lead to an important decrease of PV efficiency. Increase of relative humidity induces a decrease of PV efficiency in both areas (Niamey and Abidjan). A power loss up to 12.46% is observed in Niamey after 21 days of dust accumulation.

The Study of Thermal Mass as a Passive Design Technique for Building Comfort and Energy Efficiency

The day/night （diurnal） changes in temperature and solar radiation pose challenges for maintaining human thermal comfort in buildings. Passive and energy-conserving buildings seek to manage the available thermal energy by lowering peaks and dampening the fluctuations in order to maintain conditions for human comfort. Appropriate use of thermal mass moderates the internal temperatures by averaging diurnal extremes. Thermal mass is one of the powerful tools which architects and designers can use to control temperature. It can be used to optimize the performance of energy-conserving buildings that rely primarily on mechanical heating and cooling strategies. Massive building envelopes-such as masonry, concrete, earth, and insulating concrete forms （ICFs） can be utilized as one of the simplest ways of reducing building heating and cooling loads. This article analyses the role and effectiveness of thermal mass as a strategy for providing indoor thermal comfort for passive solar and energy conserving buildings.

A Study on the Efficiency Gain of CsSnGeI3 Solar Cells with Graphene Doping

This paper presents a newly designed ultra-thin, lead-free, and all-inorganic solar cell structure. The structure was optimized using the SCAPS-1D simulator, incorporating solid-state layers arranged as n-graphene/CsSnGeI3/p-graphene. The objective was to investigate the potential of utilizing n-graphene as the electron transport layer and p-graphene as the hole transport layer to achieve maximum power conversion efficiency. Various materials for the electron transport layer were evaluated. The optimized cell structure achieved a maximum power conversion efficiency of 20.97%. The proposed solar cell structure demonstrates promising potential as an efficient, inorganic photovoltaic device. These findings provide important insights for developing and optimizing inorganic photovoltaic cells based on CsSnGeI3, with n-graphene electron transport layers and p-graphene hole transport layers.

Possibilities of Using Solar Energy in District Cooling Systems in the Mediterranean Region

Use of district heating and cooling systems has many environmental advantages compared to individual heating and cooling. Recent advances in solar energy technologies for heat and power generation have reduced their cost and promoted their use instead of fossil fuels. Solar-PV energy for electricity generation and solar thermal energy for hot water production are broadly used today. Solar energy resources in the Mediterranean region are abundant while space cooling in buildings is required when solar irradiance is high. The possibility of using solar energy for fuelling water chillers providing cold water in district cooling systems in the Mediterranean basin has been investigated. Existing literature and studies concerning the use of district cooling systems globally as well as the energy sources used in them have been examined. Solar-PV energy combined with compression chillers and solar thermal energy combined with thermally driven chillers can be used for cold water production. Their overall efficiencies, converting solar energy to cold water, vary between 22% and 56% compared with 45% for compression chillers using grid electricity. It is concluded that various solar energy technologies could be used with different types of water chillers for fuelling district cooling networks in the future in the Mediterranean region.

Thermodynamic Investigation of a Solar Energy Cogeneration Plant Using an Organic Rankine Cycle in Supercritical Conditions

In the present work,a novel Organic Rankine Cycle(ORC)configuration is used for a low-grade heat source cogeneration plant.An investigation is conducted accordingly into the simultaneous production of electricity and cold.The proposed configuration relies on concentrated solar power(as heat source)and ambient air(for cooling).Furthermore,two gas ejectors are added to the system in order to optimize the thermodynamic efficiency of the organic Rankine cycle.The results show that the thermodynamic and geometric parameters related to these ejectors have an important effect on the overall system performances.In order to account for the related environmental impact,the following working fluids are considered:HCFC-124,HFC-236fa,HFO-1234yf and HFO-1234ze.As shown by the numerical simulations,the fluid R1234yf presents the minimal heat consumption and therefore provides an optimal thermal efficiency for the ORC cycle(which is around 29%).However,the refrigerant R236fa displays the highest refrigeration performances with a performance coefficient reaching a value as high as 0.38.

A Thiazole-Based Polymer Donor for Efficient Organic Solar Cells

The development of new materials plays a critical role in improving the efficiency of organic solar cells(OSCs).At present,the relatively high-lying highest occupied molecular orbital(HOMO)level of the high-efficiency polymer donor is regarded as one of the main reasons for the low open-circuit voltage(V_(OC)).In this work,we introduced the strong electron-withdrawing thiazole unit into the construction of a polymer donor.We designed and prepared an alternating donor-acceptor material,namely PSZ,by copolymerizing 4-methyl thiazole with an electron-donating benzodithiophene unit and studied its application in high-efficiency OSCs.The optical and electrical properties of the new material were characterized by UV-Vis absorption spectroscopy and electrochemical cyclic voltammetry.Results show that PSZ is a typical wide-bandgap material with a high optical bandgap of 2.0 eV and a deep HOMO level of-5.70 eV.When a non-fullerene BTP-eC9 was selected as the acceptor material,V_(OC) reached 0.88 V in the resulting device,and the corresponding power conversion efficiency(PCE)was8.15%.In addition,when PSZ was added as the third component to the binary photoactive combination with PBDB-TF as the donor and BTP-eC9 as the acceptor,V_(OC) of the cell device could be increased,thereby obtaining a high PCE of 17.4%.These results indicated that introducing thiazole units into polymer donors can remarkably reduce the HOMO levels and improve V_(OC) and PCE in OSCs.

Transforming Energy Usage: It’s Not Only about Solar

GRID Alternatives, a non-profit solar contractor, installs solar electric systems for low-income families. Part of GRID Alternatives’ program is to provide solar electric systems that are designed to replace 75% of the homeowners’ electricity usage with solar power. This leaves 25% of their bill still to be paid. In order to save our resources, one must first use conservation practices, then energy efficiency, and then follow-up with renewable energy to cover the rest. GRID Alternatives Inland Empire (GRID IE) educates our participating homeowners and community members on this philosophy. However, measuring whether or not our families have been following this philosophy is hard to prove. It may seem obvious that if we want to know whether our homeowners are saving energy, we should look at their energy usage before and after solar. However, this is not the case with our low-income families that could be using electricity to make their lives more comfortable. GRID IE developed a survey to be given before homeowners received their solar systems and started their participation with GRID Alternatives and the same survey to be given after they have received their solar systems. This before and after survey (pre-test/post-test) asked our homeowners to rate their responses to 7 questions on a scale of 1 - 10. The before and after responses for each person were compared, and as a group, their differences were calculated to find out if the differences were statistically significance (within subjects, dependent Z test). 6 out of 7 questions showed statistical significance. The big picture is that change is happening among our low-income homeowners and has happened for many of the varied energy saving methods discussed. It is important to transform energy usage, because the solution is not just solved with solar.

Conception of the Solar Regulator for Renewable Energy

In this work, we are interested in conducting a technological research on the use of the renewable energy, particularly the “photovoltaic” to achieve a complete system for the controlled production of energy. In fact, we talked about the different types of renewable energy and their importance to the economic sector;photovoltaic cells and its operating principle, modeling, current-voltage characteristics and the influence of parameters on the performance of energy that makes us think to make followers continued to enjoy the maximum of energy. The integration of regulator renewable energy in the embedded system by using a microcontroller.

Method of 3D Solar Energy Conversion

The problem of collecting solar energy and increasing its efficiency was studied in this paper. It was discovered that a 3DPV （three-dimensional photovoltaic） structures can generate greater amounts of measured energy densities than stationary flat PV panels （rate： 2 to 20）. It has been found that the same structures work better not only because they are made in 3D but because PV panels do not have linear dependency on geometry. It seems that the conversion efficiency depends on the process of absorption of the solar energy, too, or in other words on the E. Yablonovich limit. The findings suggest that the quantity of material of solar panels may be reduced to generate the same amount of electricity.

LVDC: An Efficient Energy Solution for On-Grid Photovoltaic Applications

In this paper some photovoltaic, PV, conversion chains architectures for on-grid applications have been proposed and the advantage of the direct use of a Low Voltage Direct Current (LVDC) bus for the DC loads has been shown. The evaluation of the efficiency of the proposed chains compared to the classical one was performed. It is shown that LVDC use instead of standard AC plugs, in numerous applications, is promising in future. The registered annual saved energy can exceed 25% of the PV generated energy. This important rate, the need of better services at lower economic cost and environmental burden will incite to make reflection about industry and supplies’ future standards.

Numerical Study and Optimization of CZTS-Based Thin-Film Solar Cell Structure with Different Novel Buffer-Layer Materials Using SCAPS-1D Software

This study explored the performances of CZTS-based thin-film solar cell with three novel buffer layer materials ZnS, CdS, and CdZnS, as well as with variation in thickness of buffer and absorber-layer, doping concentrations of absorber-layer material and operating temperature. Our aims focused to identify the most optimal thin-film solar cell structure that offers high efficiency and lower toxicity which are desirable for sustainable and eco-friendly energy sources globally. SCAPS-1D, widely used software for modeling and simulating solar cells, has been used and solar cell fundamental performance parameters such as open-circuited voltage (), short-circuited current density (), fill-factor() and efficiency() have been optimized in this study. Based on our simulation results, it was found that CZTS solar cell with Cd0.4Zn0.6S as buffer-layer offers the most optimal combination of high efficiency and lower toxicity in comparison to other structure investigated in our study. Although the efficiency of Cd0.4Zn0.6S, ZnS and CdS are comparable, Cd0.4Zn0.6S is preferable to use as buffer-layer for its non-toxic property. In addition, evaluation of performance as a function of buffer-layer thickness for Cd0.4Zn0.6S, ZnS and CdS showed that optimum buffer-layer thickness for Cd0.4Zn0.6S was in the range from 50 to 150nm while ZnS offered only 50 – 75 nm. Furthermore, the temperature dependence performance parameters evaluation revealed that it is better to operate solar cell at temperature 290K for stable operation with optimum performances. This study would provide valuable insights into design and optimization of nanotechnology-based solar energy technology for minimizing global energy crisis and developing eco-friendly energy sources sustainable and simultaneously.

Theoretical and Experimental Quantification of Solar Radiation through a Tracking System

This work deals with the estimation of solar radiation through a solar tracker aimed at evaluating the effect of solar tracking on the solar deposit in Burkina Faso. Using a two-axis solar tracking system, we experimentally measured solar radiation at our Joseph KI-ZERBO University site and compared it with that obtained by a numerical simulation run using Fortran programming software based on a mathematical model by Brichambaut. The results obtained from the mathematical and experimental studies show that, with a solar tracker, on a clear-sky day, solar irradiation is between 800 W·m−2 and 1000 W·m−2 between about 8 a.m. and 4 p.m., i.e. a duration of 8 hours of insolation. Analysis of the numerical and experimental results shows very good quantitative and qualitative agreement, with an average relative error of 18%.

Chlorinated Thiazole-Based Low-Cost Polymer Donors for High Efficiency Binary and Ternary Organic Solar Cells

In this work,novel D-A alternating polymers(PJ-1,PJ-2,and PJ-3)with chlorinated benzodithiophene and chlorinated thiazole units were synthesized via gradual chlorination.These polymers could be obtained readily through a few concise synthesis steps.Among them,PJ-1 displayed desirable properties including energy levels,crystallinity,and charge transport capabilities.The binary and ternary organic solar cells(OSCs)fabricated based on PJ-1 displayed significant power conversion efficiency(PCE)of 15.02%and 19.12%,respectively,placing them among the highest reported for ternary OSCs.Notably,the PJ1-based devices also showcased one of the highest figure-of-merit values,indicating their promising potential for future applications.This study offers valuable insights and supports the development of costeffective and high-performance polymer donors for the generation of OSCs.

Piperazine-Assisted Construction of 2D/3D Wide-Bandgap Perovskite for Realizing High-Efficiency Perovskite/Organic Tandem Solar Cells

Monolithic perovskite/organic tandem solar cells(TsCs)have gained significant attention due to their easy device integration and the potential to surpass the Shockley-Queisser limit of single-junction solar cells.However,the surfaces of wide-bandgap perovskite films are densely populated with defects,leading to severe non-radiative recombination and energy loss.As a consequence,the power conversion efficiency(PCE)of perovskite/organic TSCs lags behind that of other TSC counterparts.To address these issues,we designed a functional ammonium salt,4-(2-hydroxyethyl)piperazin-1-ium iodide(Pzol),comprising a piperazine iodide and a terminated hydroxyl group,which was applied for post-treating the perovskite surface.Our findings reveal that Pzol reacts with and consumes residual PbX_(2)(X:I or Br)to form a 2D perovskite component,thereby eliminating Pb^(0)defects,while the terminated hydroxyl group in PZOI can also passivate uncoordinated Pb^(2+).Consequently,the shallow/deep-level defect densities of the 2D/3D perovskite film were significantly reduced,leading to an enhanced PCE of single-junction 2D/3D wide-bandgap perovskite solar cells to 18.18% with a reduced energy loss of 40 mev.Importantly,the corresponding perovskite/organic TSCs achieved a remarkable PCE of 24.05% with enhanced operational stability(T_(90)~500h).

Dual-Roof Solar Greenhouse—A Novel Design for Improving the Heat Preserving Capacity in Northern China

Dual-roof solar greenhouse, a new style of solar greenhouse, was designed in this study intending to reduce heat loss in cold time and improve land use efficiency in Beijing, the Capital city of China. Designing and applying the dual-roof greenhouse in metropolitan area had dual effects of saving energy and enhancing land use efficiency. According to the monitoring study and analysis conducted in winter of 2012, the averaged night temperature of south room was about 12.1°C in December, which was satisfying for growing average leaf vegetables. Total energy saved by dual-roof in whole winter was quantified as 1.1 × 107 MJ&#46yr-1 (winter), potentially about 37.4 t coal was saved in Beijing area during whole winter-growing period. Considering the application of north room, the land use efficiency was improved by 62.5% in dual-roof solar greenhouse.

Design and Analysis of Parabolic Trough Solar Water Heating System

Renewable energy technology is one of the prospective sources which can meet the energy demand and can contribute to achieve sustainable development goals.Concentrated collectors are widely used in solar thermal power generation and water heating system also.It is very popular due to its high thermal efficiency,simple construction requirements and low manufacturing cost.This paper is concerned with an experimental study of parabolic trough collector for water heating technology.It focuses on the performance of concentrating solar collector by changing the reflector materials(aluminum sheet,aluminum foil and mirror film).In Bangladesh,it is possible to use low cost solar concentrating technologies for domestic as well as industrial process heat applications.The line focusing parabolic trough collectors have been designed,developed and evaluated its performance by collecting solar radiation,inlet and outlet water temperature,flow rate,efficiency etc.

Optimal Performance for Solar Thermal Power System

Solar thermal power is currently one of the important trends and research hotspots of solar energy. In present paper, basic physical model is proposed to investigate the solar thermal power, and the operating temperature is optimized to maximize the electricity generating efficiency. When the concentrated energy flux rises, the absorption efficiency of heat receiver will first increase and then decrease, while the increasing of flow velocity can improve the absorption performance. As the working temperature rising, the heat loss of infrared radiation and natural convection increases quickly, so the absorption efficiency obviously decreases, while the Carnot efficiency of the steam turbine cycle will rise. Because of the coupling effects of the heat absorption cycle and turbine cycle, the electricity generating efficiency will reach maximum with the optimal working temperature.