Power Evaluation of the Los Angeles Oxygen–Fed Ozone System

The Los Angeles Department of Water and Power (LADWP) operates a 600 mgd (2,270 ML/day) direct filtration water treatment plant which includes a 7,900 lb/day (149 kg/hr) ozonation system. Ozone is applied as a preoxidant for the purposes of disinfection and microflocculation. The ozonation system is unique in that high purity oxygen is generated on–site and is used as the feed–gas in a once–through system. The process was selected through competitive bids and evaluated for total present worth from 20–year life cycle costs which included capital plus energy expenses. Power consumption (and penalty) was valued at $6,500/kW. System power demand was measured at nine ozone production rates. A minimum specific energy of 6.5 kWh/lb (14.3 kWh/kg) of ozone was observed when generating ozone at a concentration between 5 and 6 % (wt) [65 and 80 g/m³; where the standard temperature and pressure are 70F (21.11 C) and 1 atm, respectively]. The test methodology and data assessment considerations were developed jointly by the owner and manufacturer, and produced results with practical significance beyond the performance testing objective.     

Development of high-performance planar borohydride fuel cell modules for portable applications

Direct borohydride fuel cell (DBFC) as a liquid type fuel cell is promising for portable applications. In this study, we report our recent progress in the micro-fuel cell development. A power density of 80 mW cm⁻² was achieved in passive mode at ambient conditions when using the anode containing nickel, carbon-supported Pd catalyst and Nafion ionomer. Current efficiency was also found to be greatly increased due to the use of Nafion rather than polytetrafluoroethylene (PTFE). Based on improvements on single cell performance, planar multi-cell power modules were assembled to study the feasibility of making high-performance and practical DBFC power units. A power of 2.5 W was achieved in a fully passive eight-cell module after significantly simplifying cell structure.     

太阳能建筑的困境

该文从哲学、社会、经济、技术以厦美学的角度探讨了当今太阳能建筑所面临的困境，揭示了制约太阳能建筑发展的矛盾问题。从批判的视角提出了太阳能建筑发展所需解决的认识问题。     

利用GTD分析微波双反射面天线效率

本文根据场相关定理,应用几何绕射理论(GTD),分析计算主面为抛物面,副面为任意旋转对称面的微波双反射面天线效率.通过实际证实,运算简明,效果良好.     

Feedback control procedure for energy efficiency optimization of microwave-heating ovens

This paper presents an automatic calibration procedure that permits to industrial or domestic microwaves ovens working at optimal energetic efficiency conditions. This method is based on a low-power iterative measurement of the microwave oven scattering parameters for several sample locations to find the most efficient position by measuring energy reflections at feeding ports and the coupling between them for each sample position. These low-power measurements have been validated through high-power microwave-heating tests showing that, at the optimal estimated position, microwave absorption and therefore temperature increment is maximum. The method provides good matching levels independently of the sample geometry and permittivity without the need of any external matching device.     

Optimization of a hospital room by means of CFD for more efficient ventilation

This paper analyses the ventilation airflow pattern in a two-bedded hospital room. The whole space of the room is divided in modules by means of curtains and internal partition walls. This configuration has many advantages from the point of view of comfort and medical assistance, but it implies an important restriction as far as ventilation is concerned. The ventilation system consists of an induction unit placed inside the hall ceiling blowing into the room and an exhaust fan in the bathroom. Numerical model solves mass, momentum and mean age of air equations assuming isothermal and stationary flow. Ventilation is evaluated analysing the age of air and the velocity fields inside the room. The results with the initial architectural design of the room show a very deficient ventilation at the patients site. Alternative configurations have been studied, allowing for correct ventilation without renouncing to the assistance advantages. Finally, the optimum configuration of the room is provided, regarding both the comfort of the patients and the cost of execution.     

Numerical simulation of the solar chimney power plant systems coupled with turbine

Numerical simulations have been carried out on the solar chimney power plant systems coupled with turbine. The whole system has been divided into three regions: the collector, the chimney and the turbine, and the mathematical models of heat transfer and flow have been set up for these regions. Using the Spanish prototype as a practical example, numerical simulation results for the prototype with a 3-blade turbine show that the maximum power output of the system is a little higher than 50 kW. Furthermore, the effect of the turbine rotational speed on the chimney outlet parameters has been analyzed which shows the validity of the numerical method advanced by the author. Thereafter, design and simulation of a MW-graded solar chimney power plant system with a 5-blade turbine have been presented, and the numerical simulation results show that the power output and turbine efficiency are 10 MW and 50%, respectively, which presents a reference to the design of large-scale solar chimney power plant systems.     

Efficiency and fuel utilization of methane-powered single-chamber solid oxide fuel cells

The single-chamber solid oxide fuel cell (SC-SOFC) is a simplification of the conventional dual-chamber SOFC and has great potential for meeting portable power generation needs. While the high energy density of hydrocarbon fuels makes SC-SOFC a promising candidate as a power source for scenarios where portability is most preferred, the low efficiency and fuel utilization reported by many experimental groups have presented a major barrier keeping it from real application.     

Potential benefits from improved energy efficiency of key electrical products: The case of India

The economy of the world's second most populous country continues to grow rapidly, bringing prosperity to a growing middle class while further straining an energy infrastructure already stretched beyond capacity. At the same time, efficiency policy initiatives have gained a foothold in India, and promise to grow in number over the coming years. This paper considers the maximum cost-effective potential of efficiency improvement for key energy-consuming products in the Indian context. The products considered are: household refrigerators, window air conditioners, motors and distribution transformers. Together, these products account for about 27% of delivered electricity consumption in India. The analysis estimates the minimum Life-Cycle Cost option for each product class, according to use patterns and prevailing customer marginal rates in each sector. This option represents an efficiency improvement ranging between 12% and 60%, depending on product class. If this level of efficiency was achieved starting in 2010, we estimate that total electricity consumption in India could be reduced by 4.7% by 2020, saving over 74 million tons of oil equivalent and over 246 million tons of carbon dioxide emissions. Net present financial savings of this efficiency improvement totals 8.1 billion dollars.