Lighting controls: Survey of market potential

This study describes the impact of lighting management systems that dynamically control lights in accordance with the needs of occupants. Various control strategies are described: scheduling, tuning, lumen depreciation, and daylighting. From initial experimental results, the energy savings provided by each of the above strategies are estimated to be 26, 12, 14, and 15%, respectively.Based upon a cost of $0.05–0.10 per kWh for electric energy and a 2-, 3-, or 4-yr payback, target costs for a simple and a sophisticated lighting management system are found to be $0.24 and 1.89 per ft², respectively, for a cost-effective investment.A growth model, based upon an extrapolation of the increase in building stock since 1975, indicates that the commercial and industrial (C & I) building stock will grow from 40 × 10⁹ ft² in 1980 to about 67 × 10⁹ ft² by the year 2000. Even with the use of more efficient lighting components, the energy required for this additional C & I stock will be 307 × 10⁹ kWh compared to the 230 × 10⁹ kWh used today. Adopting controls would reduce this requirement to 243 × 10⁹ kWh, an increase of only 13 × 10⁹ kWh above current use.The specified information is used to analyze the economic impacts that using these systems will have on the lighting industry, end users, utility companies, and the nation's economy. A $1–4 × 10⁹ annual lighting control industry can be generated, creating many jobs. The estimated return on investment (ROI) for controls for end users would be between 19 and 38%. Utilities will be able to make smaller additions to capacity and invest less captial at 7–10% ROI. Finally, the annual energy savings, up to $3.4 × 10⁹ for end users and about $5 × 10⁹ for utilities, representing unneeded generating capacity, will be available to capitalize other areas of our economy.     

Effect of residual hydrogen content on the tensile properties and crack propagation behavior of a type 316 stainless steel

The tensile properties and crack propagation rate in a type 316 austenitic stainless steel prepared by vacuum induction melting method with different residual hydrogen contents (1.1–11.5 × 10⁻⁶) were systematically investigated in this research work. The room temperature tensile properties were measured under both regular tensile (12 mm/min) and slow tensile (0.01 mm/min) conditions, and the fracture properties of the tensile fractures with both rates were analyzed. It shows that the hydrogen induced plasticity loss of stainless steel strongly depends on the tensile rate. Under regular tensile condition, there is no plastic loss even when the hydrogen content is up to 11.5 × 10⁻⁶ while in the slow tensile condition, the plastic loss can be clearly identified rising with the increasing H contents. The fatigue crack propagation rate was tested at room temperature, and the crack growth rate formula (Paris) of the 316 stainless steels with varied H contents were obtained. The fatigue crack propagation rate test shows that the crack growth rate of the 316 stainless steel with 8.0–11.5 × 10⁻⁶ hydrogen is significantly higher than that of benchmark steel.     

Evaluation of structural,electronic, thermoelectric,and optical results of C-doped HfO2 by first-principle's investigation

In this work, we report the ab initio numerical simulation investigation on the crystal lattice, electronic structure, optical, and transport properties of pure and C-doped crystalline hafnium dioxide (c-HfO₂) using FP-LAPW method. Different exchange correlation functionals like generalized gradient approximation (GGA) of PBE-sol and Tran and Blaha's modified Becke-Johnson exchange potential (mBJ) within density functional theory have been used. Two kinds of defects in cubic pure HfO₂ have been investigated: one is substitution of Hf atom by C impurity and other substitution of O atom by C impurity in crystalline HfO₂. The computed results indicate that impurity energy bands as a result of 2p states of C are found to present in the band gap of c-HfO₂. Few of these bands are present at the conduction band minimum, which results to a noteworthy band gap contraction, and hence electrons close to Fermi level get transferred in doped c-HfO₂. We have also analysed the dielectric function, absorption coefficient, optical conductivity, optical function, electron energy loss, and reflectivity for both pure HfO₂ and doped with C. Furthermore, the temperature-dependent transport properties of C-doped HfO₂ are also discussed in terms of Seeback coefficient, thermal conductivities, electronic conductivities, power factor, and figure of merit in the temperature range 0 to 1200 K. The calculated value of PF for pure HfO₂ was found to increase from 0.01 × 10¹² WK⁻²m⁻¹s⁻¹ at 50 K to 1.79 × 10¹² WK⁻²m⁻¹s⁻¹ at 1200 K and for HfO_{2(1 − x)}C_x it was found to increase from 0.06 × 10¹² WK⁻²m⁻¹s⁻¹ at 50 K to 0.25 × 10¹² WK⁻²m⁻¹s⁻¹ at 1200 K.     

Effect of polyaniline on the electrical conductivity and activation energy of electrospun nylon films

Nano films of nylon 6 and polyaniline (0, 1, 2, 3, 4, 5, and 6 wt. %) were prepared by the electrospinning technique. The addition of polyaniline increased the electrical conductivity of nylon 6. Pure nylon had an electrical conductivity of 3.8 × 10^?3 S/cm, while the conductivity of nylon 6 with 1% polyaniline was 10.2 × 10^?3 S/cm. In addition, the electrospinning process increased the electrical conductivity of bulk nylon 6 from 10^?14 S/c to 10.2 × 10^?3 S/cm. The viscosity and surface tension of nylon 6 decreased with increasing polyaniline content. The morphology of the prepared films was observed with SEM, and the average diameter of the fibre diameters, which was measured statically from the SEM images, was found to be 74 nm for a nylon film with 4 wt.% polyaniline, and 180 nm for pure nylon. The nanofibre films showed an enhanced electrical conductivity with increasing polyaniline concentration, from 2.627 × 10^?10 S/cm for a pure nylon film to 3.44 × 10^?7 S/cm for a nylon film with 6 wt.% polyaniline. The activation energy decreased with increasing polyaniline concentration. The activation energy was 0.135, 0.0899, 0.0864, 0.0811, 0.078, 0.075 and 0.07299 eV for pure nylon, and nylon with 1, 2, 3, 4, 5, and 6 wt.% polyaniline, respectively. The activation energy of the prepared nylon films decreased in comparison with the activation energy of a pure nylon 6 film, while the electrical conductivity increased as the amount of polyaniline was increased.     

Theoretical analysis of green hydrogen from hydropower: A case study of the Northwest Columbia River system

Within the Pacific Northwest region of the United States, there is the unique opportunity to explore alternative energy management solutions of the Columbia River's multi-use hydropower system. As with various European hydropower systems that experience large variability in water runoff, but lack adequate reservoir storage capacity, the Columbia River System is a viable source for renewable hydrogen production. This paper studies the theoretical potential of green hydrogen production from excess hydropower energy from the Columbia River System. The potential surplus hydroelectric energy and hydrogen production potential from surplus energy (during March through July months) are estimated from 11 hydroelectric projects along with the Columbia River System. Results show that the system's total monthly average hydrogen production potential ranges from 2.22 × 10⁶ to 8.96 × 10⁶ kg H₂ with the utilization of surplus energy over a historical 80 water year period (1928–2008). This study concludes that hydrogen production from spilled hydropower energy and its use in the transportation sector is a viable opportunity to lead the country towards a hydrogen economy.     

CO2 mitigation options and barriers to implementation in the Jordanian energy-sector

In 1995, Jordan's annual emissions of greenhouse gases (GHGs) were approximately 13.8×10⁶ tonnes, of which fossil-fuel combustion contributed more than 85%. It is likely that CO₂ emissions, from energy operations, will rise to about 20×10⁶ tonnes in the year 2010, when the energy consumption will be twice that in 1995. There are many viable CO₂-mitigation measures identified for the energy sector, some of these can be considered as attractive opportunities. However, their implementation requires the removal of certain obstacles, such as the lack of awareness, lenient energy pricing policies and lack of access to appropriate technology.     

Sun drying of cocoa with firebrick thermal storage materials

The thin-layer drying process of N38 cocoa beans using open-sun and a solar drying (SD) system with firebrick heat storage materials (FTSM) has been modeled. The 10 kg capacity force convective SD system was developed and used to carry out the experiments. The choice of the best model was based on a comparison of statistical indicators including determination coefficient (R²), reduced chi-square (χ²), root mean square error (RMSE), sum of square error (SSE), and normalized root mean square error (NRMSE) after fitting the experimental results to 11 common thin layer models in the literature. The results revealed that under open-sun drying and SD processes, the Midilli et al model provided the best drying characteristics of cocoa beans. Therefore, in the experimental context, this model can be assumed to reflect the solar/sun drying behavior of cocoa. The effective diffusivity values for the open-sun and SD of cocoa with FTSMA and FTSMB were 4.25× 10⁻¹¹, 6.64× 10⁻¹¹, and 5. 95 × 10⁻¹¹ m²/s respectively. The predicted pre-exponential factor and activation energy were 5.81 × 10⁻¹¹ m²/s and 22.79 kJ/mol respectively.     

Quantitative appraisal and potential analysis for primary biomass resources for energy utilization in China

As the largest agricultural country, China has abundant biomass resources, but the distribution is scattered and difficult to collect. It is essential to estimate the biomass resource and its potential for bioenergy utilization in China. In this study, the amount of main biomass resources for possible energy use and their energy utilization potential in China are analyzed based on statistical data. The results showed that the biomass resource for possible energy use amounted to 8.87 × 10⁸ tce in 2007 of which the crops straw is 1.42 × 10⁸ tce, the forest biomass is 2.85 × 10⁸ tce, the poultry and livestock manure is 4.40 × 10⁷ tce, the municipal solid waste is 1.35 × 10⁶ tce, and the organic waste water is 6.46 × 10⁶ tce. Through the information by thematic map, it is indicated that, except arctic-alpine areas and deserts, the biomass resource for possible energy use was presented a relatively average distribution in China, but large gap was existed in different regions in the concentration of biomass resources, with the characteristics of East dense and West sparse. It is indicated that the energy transformation efficiency of biomass compressing and shaping, biomass anaerobic fermentation and biomass gasification for heating have higher conversion efficiency. If all of the biomass resources for possible energy use are utilized by these three forms respectively, 7.66 × 10¹² t of biomass briquettes fuel, 1.98 × 10¹² m³ of low calorific value gas and 3.84 × 10¹¹ m³ of biogas could be produced, 3.65 × 10⁸ t to 4.90 × 10⁸ t of coal consumption could be substituted, and 6.12 × 10⁸ t to 7.53 × 10⁸ t of CO₂ emissions could be reduced. With the enormous energy utilization potential of biomass resources and the prominent benefit of energy saving and emission reduction, it proves an effective way to adjust the energy consumption structure, to alleviate the energy crisis, to ensure the national energy security and to mitigate the global warming trend.     

The status,predicament and countermeasures of biomass secondary energy production in China

China is rich in biomass resources, with favorable conditions for the development and utilization of biomass energy. Currently, the main secondary forms of biomass energy utilized in China include biogas, biomass power, bioethanol, biodiesel. By the end of 2010, the annual output of biogas in China had reached 14.3×10⁹ m³; the installed capacity of biomass power had reached 5.5×10⁶ kw; the annual output of bioethanol had reached 1.84×10⁶ t; the annual output of biodiesel was 400×10³ t. Although China is very rich in biomass resources, the percentage of biomass energy in the total energy utilized in China is very low. In 2010, the biomass secondary energy accounted for 7.28% of the total renewable energy consumption; and only 0.66% of the primary energy consumption in China. Compared with other types of renewable energy, the biomass energy development remains very slow and even marginalized. The development of secondary sources of energy in China is relatively slow, the reasons for which are many, such as food security, high production costs, obsolete equipment, technological immaturity, insufficient raw materials, and a serious shortage of investments. In fact, the root causes for the slow development of the biomass secondary energy industry are the government's focus on economic development and the private enterprises focus on economic benefits. The lower economic benefits of the biomass secondary energy industry do not intrinsically motivate them to promote its development. Entering the market is crucial to the development of the biomass secondary energy and requires strong implementation and policy guarantees by the government. Biomass secondary energy has a positive role in reducing greenhouse gas emission, reducing waste pollution, and increasing employment opportunities. It is recommended that the government and enterprises should actively promote the development of the biomass secondary energy.     

Particle swarm optimization algorithm for ignition of hydrogen isotopes (deuterium–tritium) pellets

Recent improvements on high power lasers have made access to dense and hot plasmas possible realizing the inertial confinement fusion (ICF). Results from Osaka University experiments found that higher energy gains are reachable through ideal adiabatic shock-free volume ignition. Laser pulses limit the range of laser input energy. Thus, it becomes necessary to make efficient use of available energy to obtain the highest gain. The present paper aims to investigate the attainment of highest gain for D–T fuel using this energy with iteration model. It is shown that the maximum gain of 1.36 × 10⁶ is obtained only at input energy of 7.27 × 10¹⁰ J, volume of 0.586 cm³ and 8133times of solid state density.     

An analysis of China's coal supply and its impact on China's future economic growth

Many people believe that China's economic growth can continue almost indefinitely. For a manufacturing-based economy such as China's to continue to grow, it needs an adequate supply of inexpensive energy. To date, this energy growth has primarily come from coal, but China's indigenous coal supplies are now falling short of the amount needed to support this growth. In this situation, the status of China's future coal supply will be very important for China's future economic development. Our analysis shows that China's ultimate recoverable coal reserves equal 223.6×10⁹ MT, and its production will peak between 2025 and 2030, with peak production of approximately 3.9×10⁹ MT. The extent to which China can import coal in the future is uncertain. With rising coal demand, this combination is likely to create a significant challenge to China's future economic development.     

Approximate evaluation of operating conditions and effectiveness of solar impurity thermovoltaic element

The effectiveness of solar impurity thermovoltaic elements based on semiconductors with forbidden gap width 0.3 eV with thin highly doped p- and n-layers with concentration ∼5 × 10¹⁹ cm⁻³, containing in addition a deep impurity with concentration ∼4 × 10¹⁸ cm⁻³ and ionization energy 0.15 eV, is shown to reach 30–40% with solar radiation intensity 0.1 W/cm².     

Chemo-mechanical coupling model of solid oxide fuel cell under high-temperature oxidation

Solid oxide fuel cell (SOFC), which is a generation device that converts chemical energy into electrical energy, has been regarded as a new generation device. The diffusion mechanism of metal cations and anions during the high-temperature oxidation process of SOFC is proposed. Based on the equilibrium expression and diffusion equation, the chemo-mechanical coupling relationship between oxide stress and thickness growth of the oxide layer is established by considering the influences of viscoplastic effect and oxide growth effect. The present theoretical result is consistent with the previous experimental results. In addition, the stress critical points corresponding to different parameters are different in initial oxidation stage. The oxide stress varies dramatically with time in the compressive stress phase, but it changes slowly in the tensile stress phase. The compressive stress that exists in the oxide layer increases with the growth coefficient (D_NiO = 1000-15 000 m⁻¹) of the oxide layer. The oxide stresses in oxide layer and electrolyte reduce with viscoplastic coefficient of the oxide layer from J_NiO = 8.97 × 10⁻⁵ Pa⁻¹ s⁻¹ to J_NiO = 16.97 × 10⁻⁵ Pa⁻¹ s⁻¹ and anode-oxide layer thicknesses from H = 30 μm to H = 660 μm, while they increase with viscoplastic coefficient of the anode from J_Ni = 3.81 × 10⁻⁵ Pa⁻¹ s⁻¹ to J_Ni = 12.81 × 10⁻⁵ Pa⁻¹ s⁻¹ and kinetic parabolic constant from k _p = 2.9 × 10⁻¹⁵ m²s⁻¹ to k _p = 12.9 × 10⁻¹⁵ m²s⁻¹ in whole oxidation stage. The oxide thickness increases with kinetic parabolic constant in the whole oxidation stage and this changing trend accords with parabolic diffusion law. The oxide thickness increases with temperatures increasing. The results obtained from this study will provide the reference to the researches of the chemo-mechanical coupling model and performance optimization of SOFC under high-temperature oxidation.     

Diffusion-limited self-discharge reaction in the Hubble space telescope battery

The self-discharge rate of aerospace flight-quality nickel-hydrogen batteries is limited by hydrogen diffusion within the nickel electrode active material. A diffusion-limited reaction model is developed which accounts for the observed self-discharge behavior. Effective hydrogen diffusion coefficients were calculated from the open-circuit self-discharge data on Hubble space telescope flight-quantified nickel-hydrogen cells and ranged from 1.12×10⁻¹⁰ cm²/sec at 25°C to 7.45×10⁻¹² cm²/sec at 0°C.     

Effect of oleylamine on microwave synthesized Cu2ZnSnS4 nanocrystals for photovoltaic junctions

Cu₂ZnSnS₄ (CZTS) with its high absorption coefficient, optimal band gap, and non‐toxic, earth‐abundant elemental constituents is a promising absorber material for low cost and high‐performance photovoltaics. CZTS nanocrystals were prepared by microwave‐assisted thermolysis method using ethylene glycol solvent in a rapid and energy efficient process with and without oleylamine as additional capping agent. X‐ray diffraction data indicated crystallite sizes of 5 and 12 nm respectively. Raman spectra showed the formation of pure Cu₂ZnSnS₄ phase in both cases. With pure ethylene glycol solvent, field emission scanning electron microscopy images showed particle sizes around 250 nm, ultraviolet‐visible absorption data gave optical band gap of 1.52 eV and Hall measurements yielded electrical resistivity ~70 Ωcm, carrier density ~2.7 × 10¹⁶/cm³, and hole mobility ~3.24 cm²/Vs. Adding optimum amount of oleylamine reduced the particle size to 100 nm and lower. The optical band gap reduced to 1.48 eV and electrical resistivity, carrier concentration, and Hall mobility changed to ~5.9 × 10⁴ Ωcm, 2.57 × 10¹²/cm³, and 4.1 cm²/Vs respectively. A knee voltage of ~0.8 V shown by CZTS/CdS p‐n junction indicated that a good V_oc can be expected from a solar cell constructed with the CZTS nanocrystals as absorber layer.     

DFT study of the enhancement on hydrogen production by alkaline catalyzed water gas shift reaction in supercritical water

Supercritical water gasification (SCWG) is hopefully to be an acceptable choice for hydrogen production, the hydroxide ion assisted water gas shift reaction (WGSR) has been regarded as the most important reaction to generate hydrogen during the process. However, the principle of practical OH^? catalyzed reaction is not possible to acquire by experiments. Thus, density functional theory (DFT) is utilized to investigate the reaction mechanism theoretically in this work. Through first principle calculations, every species and energy barrier for elementary steps are achieved, and formate ion is determined as the important intermediate. Besides, HCOO^? + H₂O → HCO₃^? + H₂ is the dominant path to generate hydrogen, as well as the rate-determining step with 47.94 kcal/mol energy barrier. Furthermore, the reaction rate constant is calculated to be k_catalytic(s^?1) = 2.34 × 10¹²exp(?1.80 × 10⁵/RT) using transition state theory with Wigner transmission coefficient (TST/w). Lastly, supercritical water condition is demonstrated to be a favored media for WGSR, because it may dissociate, dissolve or hydrolyze more hydroxide anion than conventional steam. The results are expected to benefit the control of reaction process and the design of SCWG reactor.     

The Thailand experience in natural gas development

We describe the development of Thailand's natural gas industry, including exploration, supply, transmission, and utilization. Activities in this area started more than 10 years ago with exploration for petroleum in the Gulf of Thailand. The main transmission pipeline for natural gas from the reserves in the Gulf of Thailand to two power plants in Bangkok has been completed. The natural gas that is being delivered and which is planned for up to 1990 has all been committed to supply domestic demand in order to save energy cost, reduce foreign currency outflow, reduce dependency on imported petroleum, and provide feedstock for basic petrochemical industries. These targets have been set and based on offshore gas reserves of 16 × 10¹² ft³ supplying gas at a rate of $\text{700 × 10}{}^6\text{ft}{}^3\text{/d}$ by 1990. However, the discovery of new gas and oil reserves onshore in the central part of Thailand may provide new opportunities for Thailand to earn foreign exchange through the export of excess petroleum in the future.     

A study to optimize the potential impact of residential building energy audits

The Colorado College Energy Audit and Retrofit Program is a non-profit organization that teaches students the science and mechanics involved in energy audits and retrofit work through service–learning and community-based research projects. This approach represents a “win–win” scenario where the college contributes to maximize learning and minimize costs to the community. The method of identifying homes for energy audits has evolved from responding to homeowner requests to a proactive approach aimed at targeting older low-income neighborhoods and working with existing neighborhood associations. Recent work on the Mill Street Neighborhood in Colorado Springs, Colorado is presented in which a sample of homes (N = 14) received thermal audits, complete with blower door tests and Energy-10 computer modeling. The results are tabulated, analyzed, and extrapolated over the entire 145 homes in the neighborhood. The normally distributed ACH _n values and the skewed distributions of R _aver values and building sizes are discussed. A method of identifying unusual occupant behavior, relative to the building quality, is presented where the Home Heating Index is compared to a Building Thermal Performance Index (R _aver/ACH _n ). Estimates from extrapolation of the data predict that an investment of $146,500 USD in retrofit materials will yield a total annual neighborhood savings in energy, utility costs and GHG emissions of 9.1 × 10⁶ kBtu (9.6 × 10⁹ kJ), $146,500 USD in retrofit materials will yield a total annual neighborhood savings in energy, utility costs and GHG emissions of 9.1 × 10⁶ kBtu (9.6 × 10⁹ kJ), 64,000 USD and 555 US tons (5.0 × 10⁵ kg), respectively, providing a simple payback time of 2.3 years. This efficient method of neighborhood energy audits provides data that could support neighborhood renewal grant proposals to purchase materials for follow-up retrofits and supports municipal demand-side management programs.     

Improvement of structural and optoelectrical properties by post-deposition electron beam annealing of ITO thin films

Sn-doped In₂O₃ (ITO) thin films were deposited on a glass substrate with reactive RF magnetron sputtering and then post-deposition electro-annealed. The electron accelerating voltage was varied from 300 to 900 V, and the substrate temperature was increased to 250 °C with an electron accelerating voltage of 900 V for 20 min in a 4 × 10^?1 Pa vacuum. As-deposited and ITO films electro-annealed at low energy (≤600 eV) were found to be in the amorphous phase, while ITO films electro-annealed at 900 eV showed diffraction peaks of the ITO (222) and (400) planes. As the electron accelerating voltage increased, the electrical resistivity decreased to as low as 6 × 10^?4 Ωcm, and the mean optical transmittance also increased from 79 to 82% in the visible wavelengths. The electro-annealed films showed a higher figure of merit (1.8 × 10^?3 Ω^?1) than the as-deposited ITO films (6.7 × 10^?3 Ω^?1), indicating that electro-annealed ITO films have better optoelectrical performance than as-deposited films.     

The synthesis of a Zirfon-type porous separator with reduced gas crossover for alkaline electrolyzer

The rapid expansion of renewable energy sources presents a great challenge to balance the electric grid due to their intermittent and volatile nature. The surplus energy generation cannot be used or sold so that it is curtailed in order to maintain the grid balance. The excess power can be converted into a gaseous energy carrier, hydrogen via power-to-gas technology. Alkaline water electrolysis can be operated in a dynamic mode using renewable energy sources on a large scale. However, the risk of gas crossover across a porous separator rapidly increases when the electrolyzer operates at a low partial load or at high pressure, leading to efficiency loss and a safety issue. The commercial porous separator Zirfon PERL, which is composed of 85 wt.% zirconia nanoparticles and 15 wt.% polysulfone, exhibits a satisfactory bubble point pressure performance of approximately 2.5 bar and ionic resistance of 0.3 Ω cm². However, the Zirfon PERL separator exhibits a high hydrogen permeability value of 20 × 10⁻¹² mol cm⁻¹ bar⁻¹ sec⁻¹ due to its large average pore size of 130 nm, resulting in a limited dynamic range of the electrolyzer. Therefore, it is necessary to develop a porous separator with reduced gas crossover. In this study, we synthesize a porous ZrO₂/polysulfone composite separator by varying the amount of ZrO₂ (75-85 wt.%) via the film-casting method. The 75 wt.% ZrO₂/25 wt.% polysulfone composite separator, which contains a low amount of ZrO₂, shows a high bubble point pressure of 3.8 bar, a low ionic resistance of 0.3 Ω cm², and are reduced hydrogen permeability of 4.2 × 10⁻¹² mol cm⁻¹ bar⁻¹ sec⁻¹ compared with that of Zirfon PERL separator. The enhanced performance of this separator is attributed to the reduced average pore size of around 70 nm and high surface wettability with a contact angle of 75°. This result will help alkaline electrolyzer systems be operated as more controllable loads.