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Initial performance measures and operating experience with a 1 kWp grid-connected array near Vancouver (BC, Canada) demonstrate the viability of AC building integrated photovoltaics (BIPV) module technology. Low current draw by the inverter, and continued operation at very low insolation levels contribute to a performance benefit over small photovoltaic arrays with DC wiring and central inverters. Maximum power point tracking of individual modules is analyzed, and an increase in array power output of between 0.6% and 3.2% is observed when compared with a DC configured photovoltaic array.

Electrical transients initiated by direct or indirect lightning strikes have caused reactor trips or misoperation of the equipment in nuclear power generating stations. The effects of lightning strikes on reactor trips or misoperation of the equipment were reviewed for the period 1984 through 1998. Based upon the review, it was found that in a number of cases, the overvoltage protection devices for the control rod drive system had operated due to the lightning strikes. There were also cases where lightning strikes had partially damaged the main/startup transformers, tripped the switchyard breakers or tripped the transmission lines and, thereby, impacted the availability of the required stable offsite power sources to the nuclear power generating stations.

Advanced thermoelectric microdevices integrated into thermal management packages and low power, electrical power source systems are of interest for a variety of space and terrestrial applications. By making use of macroscopic film technology, microgenerators operating across relatively small temperature differences can be conceptualized for a variety of high heat flux or low heat flux heat source configurations. The miniaturization of state-of-the-art thermoelectric module technology based on Bi2Te3 alloys is limited due to mechanical and manufacturing constraints for thermoelement dimensions (100-200μm thick minimum) and number (100-200 legs maximum). We are developing novel thermoelectric microdevices combining high thermal conductivity substrate materials such as diamond or even silicon, thin film metallization and patterning technology, and electrochemical deposition of 10-50μm thick thermoelectric films.

Lately, because of limitedness of organic power resources and requirements to ecological purity, the solution of a problem of power production growth is more often connected with the use of renewable power resources. Among renewable power sources the ocean waves is a very promising power carrier since they manifest the highest specific power. The functioning of a Natural-Artificial Power-Industrial system is examined. The main elements of it are: - A nature's heat machine, creating the ocean waves; - A Float Wave Electric Power Station, converting wave's energy into electricity; - An electrolyzer, utilizing electricity and sea water, as a means of hydrogen production; - Energy storage and energy consumers. The system is treated from energetic, ecological and economic viewpoints.

There have been estimates that the solid waste stream of municipal garbage could be converted to 5% of the total electric power requirement. In response to this potential many high capital cost incinerators have been installed around the country during the last two decades. Success has been marginal and many have been prematurely shut down because of technical problems and public concerns about emissions and potentially toxic ash. The alternative is to continue to use landfills, but to capture the methane that is produced by the decay of organic matter for the production of heat and electricity. Several such facilities have been installed in recent years and are demonstrating increasingly favorable operation. The purpose of this project was to research the techniques and technologies that are used to harness landfill gas, along with the related considerations of state and federal regulations and public health concerns from exposing the public to unburned and uncleaned landfill gas.

The problem of energy recovery from biomass by means of a combustion process, while assuming more and more importance, accordingly with the Kyoto Protocol, is requiring as well processes able to optimize efficiencies. Such optimization should not only be related to possible plant solutions, but should also take into relevant consideration the characteristics of biomasses used, which cause, through the combustion process, different problems mainly of the environmental kind and not of easy solution. The present paper analyzes such problems by keeping in due account the different factors capable of influencing at the end the adopted solution. Particularly, the possibility to employ complex cycles is discussed with reference to both the kind of fuel employed and the plant size. It is also emphasized how the possible energy costs can condition the optimum choice, mainly if influenced by binding rules.

The specific mission was to determine the effect of driving schedules on the efficiency of battery powered electric vehicles (EV) and hybrid engine/electric vehicles (HEV). Efficiency was referenced to the hydrocarbon (HC) fuel source which provided the electrical energy. In the case of the battery powered pure electric vehicle, the HC source was referenced to the public utility HC fuels. While, in the case of hybrid electric vehicles, the HC source was carried on board the HEV in the vehicle fuel tank.

The thermal performance of a chemical heat pump using reaction system of calcium oxide/lead oxide/carbon dioxide is demonstrated by experimental results and analyses of a CaO/CO2 bed reactor. The energy analysis based on the experiments show that it is possible to utilize high temperature heat with this heat pump. This heat pump can store heat above 850°C and then output it to a heat sink above 900 °C at atmospheric pressure, facilitated by CaO carbonation. An applied system that combines the heat pump with a high-temperature process is proposed for high-efficiency heat utilization. The scale of the heat pump in the combined system is estimated from the experimental results.

High-frequency resonant power converters are an attractive choice for high power density applications, e.g., on aerospace vehicles. Until recently, most of the attention was paid to resonant converters with 2 energy-storage elements. However, it was recently pointed out that some of the drawbacks of this class of converters (including poor load regulation, discontinuous mode operation and poor transient response) could be overcome by adding a third energy-storage element to the resonant circuit. Among the many 3-element resonant converter topologies that have not yet been thoroughly investigated is one that we will refer to as the π-CLC topology. This paper will present the results of theoretical analysis and computer simulations performed on this converter topology.

This paper describes electrochemical behavior of microscopic batteries based on both the lithium/ion and Ni/Zn couples. These batteries are being developed for use in MEMS devices and other microelectronics, especially remote, autonomous sensors. Many of these applications require a combination of long cycle life, moderate energy storage capability, and periodic high power output. Batteries have been made using high-volume, lowcost, fabrication techniques, described in prior publications. These batteries have been built and evaluated for their electrochemical performance. Power output from both types of cells is impressive; current densities of 80 - 100 and 20 - 50 mA/cm2 have been observed, for discharges of several seconds, for Ni/Zn and Li/Ion cells, respectively. Much higher current densities are observed for discharges lasting a few milliseconds, such as would be needed in many applications. Specific capacities of 2 - 4 C/cm2 are also obtained.

Solar-driven generators which have closed cycles are proposed. The cycles consist of isentropic and two isobaric processes. Two types of the cycle engines are designed based on the concept. The cycle performance is calculated for normal and improved cases with the theoretical background. From the results, the improved closed cycle promises a high performance for the solar application. Actual engines are currently designed to achieve the 20% system efficiency.

A new solar furnace system using a stationary elliptic dish and heliostats is proposed. Since the elliptic dish has two focuses (an upper focus and a lower focus) for elliptic geometry, this system has three advantages. The first is enable to fix a solar reactor on the ground, the second to expand the heliostat field largely, and the third to concentrate the direct solar radiation in a small area around the lower focus. The horizontal deviation from the lower focus of the direct solar radiation was estimated within ±1.2m for the heliostat field of 100m and the tower-reflector height of 70m. The system using the elliptic dish and heliostats is available as high-concentration system due to large scale of solar energy.

Many thermodynamic texts imply that the entropy flux for thermal radiation (TR) is the same as that for heat conduction, the heat flux divided by the local temperature (q/T). However, for blackbody radiation (BR) emission a 4/3 coefficient occurs and recently it was shown that for non-blackbody radiation (NBR) the coefficient is greater than 4/3 [1]. Some of the fundamental equations that are used in thermodynamics express the entropy flux of heat transfer in a q/T type form. In this paper we address the use of the Clausius equality, and expressions extended from it for irreversible processes, when TR is involved. We find that the Clausius equality for reversible processes is applicable, while the statements extended for irreversible processes are not applicable. Also, we present an alternative derivation of the 4/3 coefficient that shows in a direct way that it follows from the observable relation between BR energy and emission temperature (i.e., energy is proportional to T4).

Multi-step water splitting with Mn-ferrite(MnFe2O4)/sodium carbonate(Na2CO3) system accompanying endothermic reaction was investigated for converting solar energy into chemical energy. This water splitting is caused by the oxidation-reduction of manganese ion in the Mn-ferrite. Multi-water splitting with MnFe2O4/Na2CO3 system was consisted of three steps. The first step was hydrogen generation at 1073K. The second step was oxygen release at 1273K. The third step was Na2CO3 reproduction at 873K. The mechanism of multi-water splitting has been considered by XRD, chemical analysis of colorimetry and back titration. The temperature range 873 to 1273K is quite lower than those studied on the solar furnace reaction (O2 releasing step) in two-step water splitting (1500-2300K). This lower temperature range would permit further progress in converting the direct solar energy into chemical energy.

Concern over the possibility of global climate change as a result of anthropogenic greenhouse gas buildup in the atmosphere is resulting in increased interest in renewable energy technologies. The World Bank recently sponsored a study to determine whether solar thermal power plants can achieve cost parity with conventional power plants. The paper reviews the conclusions of that study.

This study describes the construction and evaluation of a low energy house which should be in harmony with the environment and also be assisted by hybrid natural energy resources and unused energy. An experimental house with ground source heat pump (GSHP) was built in Hokkaido University, Japan in March, 1997. As a result of experiments, it was shown that approx. 80 % of the total energy was provided from PV modules, solar collectors, underground and exhaust heat. Annual energy consumption was 12.5 % of typical house’s one in Hokkaido. This report describes an outline of the low energy house and experimental energy balance.

This paper describes a microscopic modeling for urban surface layer, where a lot of various structures (i.e. building, bridge, pavement, and other facilities) exist. The authors found out a structural similarity between urban structure and porous media. Flow model and method of analysis in porous media were applied to the microscopic modeling for urban surface layer. First, 2-D numerical study was conducted on unsteady natural convection. Resultant model will be used for more precise 3-D computer simulation of urban warming and urban planning.

Using a panel method, the flow over various residential roof designs was analyzed and an estimate of the pressure distribution across the roof was determined. This pressure distribution was analyzed to determine the potential for flow reversal through the ventilating system of a gas-fired appliance. It was found that, for several roof configurations and wind speeds, relatively low pressures could exist on the roof of a residence. In addition, some appliance venting configurations, combined with the local pressure distribution, will impose pressures on the appliance inlet and exhaust that can result in a reversal of the normal flow direction. If the flow is reversed and the appliance is installed in a closed area like an airtight closet, hot exhaust gasses will be allowed to enter areas not designed for high temperatures and a fire can result.

As important members of the STATCOM (Static Synchronous Compensator), the passive elements play an indispensable role in the transient and steady state performance of STATCOM. The harmonics resonant phenomena have been pointed out in some papers. However from the engineering design point of view, a more detailed investigation should be conducted to give an insight into the effects of passive parameter selection on the system performance. Based on the experience in developing STATCOM, the authors proposed a modified mathematical model in a per-unit system as the base of parameter evaluation. With the proposed model, the authors analyze the influence of the per-unit passive parameters on the performance of STATCOM systematically. Simplified algebraic expressions for the magnitudes of the harmonic current as well as the dc voltage regarding the particular harmonics are derived, which can be used as an indication of the preference for the passive elements.