Certain materials, generally metal oxides, can sustain the unassisted photo-electrolysis of water into H2 and O2. The energy contained in the photons that are absorbed by these materials can in many cases be efficiently converted into energy stored into the chemical fuels produced by the photo-electrolysis system. However, these materials have optical absorption thresholds (band gaps) that are too large to permit effective absorption of the visible and infrared portions of the solar spectrum, thereby wasting a large fraction of the incident solar energy and yielding overall energy conversion efficiencies of o 1%. Modification of metal oxide materials has been claimed to be much more promising, with a modified TiO 2 photo-anode yielding 8% efficiency in the photo-assisted splitting of water into H2 and O2 . (more…)
Several molecular systems have been constructed that mimic various aspects of photosynthesis. Two of these utilize molecular system ...
The basic processes that occur in such a system are well understood. The semiconductor electrode efficiently absorbs light, produci ...
The issues of hydrogen storage run through the hydrogen production, hydrogen transport, supply and demand for end use of hydrog ...
Hydrogen has many applications when it comes to fuel. It can be used both in internal combustion engines and hydrogen fuel cells. ...
All of today’s hydrogen conversion products, demonstration models, and prototypes possess some deficiencies; they cannot yet pr ...
You must perform some sort of tour and visit of your home and property to find out exactly where it may need in applying insulation. A good rule of thumb is that most heated area or perhaps cooled places needs to be split up from unconditioned places using insulation materials. Regardless of your properties design, you can use this rule to ascertain exactly where insulation installation should be set up. Every location will have its consideration in terms of insulation simplicity and cost-effectiveness and may be examined on the basis of both. (more…)
If your house has no attic (most flat-roof houses don’t), chances are there’s a cockloft, a space between roof and ceiling, at ...
Imprinted on every batt or blanket of insulation or on every bag of loose insulation is its R-Value. The higher Insulation R-Value, ...
You know where to insulate, but there’s still one more thing you need to know about—vapor barriers. Well-insulated attics, craw ...
Using blankets the width of your wall studs, insert the blanket between the studs and staple to the studs. (The job is easier i ...
It is easier and less costly to fit insulation in a new home than to retrofit. However, many existing houses have little or no insu ...
n fabricating microscale energy systems, a number of operating conditions must first be taken into account. Foremost are the operating temperatures throughout the device. Often with mesoscale/ microscale energy systems, two closely spaced parts of the same device have a large temperature difference between them; hence, a large gradient can be present. A primary constraint is to have the material withstand the maximum temperatures existing in the system, but the gradients and thermal expansion must also be tolerated. (more…)
Silicon is the material of choice for most Micro Electro Mechanical Systems due to (1) the feature size often being in the rang ...
Extensive insulation repairs are usually done by contractors having the specific skills and equipment appropriate to the type o ...
Fuel cells are direct energy conversion devices that combine two reactants to produce electrical power. The reactants are typic ...
Microtechnology-Based Energy and Chemical Systems will most likely employ combustion for driving processes such as vapor generation ...
Insulation is what keeps the heat energy of a boiler system from leaking out of the system on its way to the end users. Inspect ...
Energy labeling is a policy tool that informs consumers about the energy performance of appliances and thereby encourages them to purchase appliances that provide the services they need with less energy consumption. In providing information to consumers about equipment energy consumption and operating costs that would otherwise be invisible or unavailable, energy labeling enables consumers to make more balanced and rational purchasing decisions. Energy labels can also help consumers to identify the most efficient products on the market. In effect, energy labeling attempts to provide a market ‘‘pull’’ for more energy-efficient products while simultaneously presenting information that might discourage the purchase of less efficient products. (more…)
It is important to remember that labeling and MEPS programs aim to influence the selection of products by consumers at the poin ...
Endorsement labels indicate that the products carrying the labels belong to the ‘‘most energy-efficient’’ class of products or ...
There are only a few compulsory energy efficiency programs aimed at industrial facilities. It is only recently that the EU introduc ...
As the need for energy efficiency becomes more pronounced, the drive toward efficiency in the commercial sector will be impeded by ...
As energy prices increase, industries are more and more aware that energy is an expensive commodity that has to be used effic ...
The energy efficiencies of various fuel production pathways from well to pump. The efficiencies shown are defined as the energy in a given fuel (available at pumps in vehicle refueling stations) divided by total energy inputs during all Well-to-Pump activities, including the energy content of the fuel. One way to interpret the Well-to-Pump efficiencies in the figure is as the difference between 100% and the energy efficiencies, which roughly represent energy losses during Well-to-Pump stages for making a given fuel available at the pump. As stated in Section 3, Well-to-Pump activities include biomass feedstock production; feedstock transportation and storage; fuel production; and fuel transportation, storage, and distribution. (more…)
The combination of well-to-pump results and the energy use and emissions associated with vehicle operation (also called the pum ...
It shows Well-to-Wheels Greenhouse Gas emissions of the 23 vehicle/fuel systems. For each system, the bottom bar represents CO2 ...
Because different studies have different system boundaries and parametric assumptions, the studies described in Section 7 resulted ...
There are different types of vehicle propulsion systems and the transportation fuels that have been studied for their potential ...
At present, in the United States and worldwide, motor vehicles are fueled almost exclusively by petroleum based gasoline (or re ...
In contrast to electromagnetic suspension systems, electrodynamic suspension systems can provide stable suspension without a feedback system. Imagine a magnet held above a moving flat sheet of aluminum or copper. Following Ampere’s law of induction, an electric field is induced in the moving metal surface that causes eddy currents to flow in closed loops near its surface. The eddy currents in turn set up their own magnetic field, whose polarity, in accordance with Lenz’s law, opposes that of the magnet’s field. Consequently, the magnet is repelled from the moving metal surface, countering the force of gravity. If the magnet is pushed down toward the moving metal surface, the induced currents and the resultant repulsive force increase, restoring the equilibrium position automatically. Conversely, if the magnet is moved upward, the levitating force decreases. (more…)
All electromagnetic suspension-based systems employ some type of feedback control mechanism to maintain stable levitation. (An inte ...
Electromagnetic Suspension (EMS) system in which an array of magnets is attracted upwards to a steel rail. It is possible to de ...
Electrodynamic Suspension (EDS) can be viewed as an array of magnets moving over a conducting sheet and being pushed upwards by ...
A propulsion alternative is to transfer power to the vehicle and then have a magnetic structure on the vehicle that can create ...
The next time you hear an airplane flying overhead, look up, and pause for a moment. What you see is a machine that is heavier than ...
The Solar City approach originally emerged from a new generation of International Energy Agency (IEA) energy research and development work to pursue citywide applications as integral to the main planning agenda. It is now adopted by the World Council for Renewable Energy (WCRE) as a basic policy and planning basis for cities. (more…)
In the absence of useful and established patterns of practice, a search is under way for new means of reconciling local government’ ...
The aim is to work with cities in advancing renewable energy technologies and systems and to help promote the renewable energy indu ...
The age of industrialization came into full force through the modern exploration and use of fossil fuels. As one of its most striki ...
The renewable energy technology and policy organization Eurosolar has in 2001 issued a blueprint program, for the use by regional p ...
As a reaction to these historical perspectives, the building industry has witnessed a certain rise in design responses to regio ...
Electric and gas utilities’ Research & Development activities deal nearly exclusively with energy conversion, distribution, and energy usage (at least to the extent that these firms still focus on these core businesses). Although detailed data on utility Research & Development are not collected systematically, it seems that Energy R&D spending by many utilities has declined during the past decade or so. For example, a 1996 survey by the U.S. General Accounting Office (GAO) found that the combined Research & Development spending of the 112 largest operating utilities in the United States dropped from $708 million in 1993 to $476 million in 1996. (more…)
Government expenditures on energy R&D, energy conservation have risen steadily over the past decade, but only two countries, Japan ...
Not surprisingly, most Energy Research and Development takes place in industrialized countries where both the public and private se ...
Nuclear fission and fusion Research and Development continues to account for nearly half of the total spending by IEA countries, al ...
Japan has the largest Photovoltaic installed capacity in the world as a result of the sustained investments made by the country thr ...
The aim of this broad sweep through the area of energy innovation, highlighting the main actors, activities, policies, institutions ...
Energy performance ratings tell what the energy performance of a building is, but if the energy performance of a building is to be improved, the causes of lower than desired performance must be understood, and methods of achieving improved performance must be determined. Causes of variation in energy performance among commercial buildings are understood to a degree, but much remains to be learned. (more…)
Current forecasts call for solid growth in world energy use over the next 20 years, potentially increasing 60% above current energy ...
Interest in rating the real-life energy performance of buildings has increased in recent years, and the real life efficiency perfor ...
As the need for energy efficiency becomes more pronounced, the drive toward efficiency in the commercial sector will be impeded by ...
The amount of energy consumed in the commercial sector often must be estimated as a fraction of energy use in the combined resident ...
The outlook for reductions in future energy use is necessarily based on the potential for increased technological and operati ...
Interest in rating the real-life energy performance of buildings has increased in recent years, and the real life efficiency performance rating of buildings is important for any sustainable energy future. (more…)
As the need for energy efficiency becomes more pronounced, the drive toward efficiency in the commercial sector will be impeded by ...
Energy performance ratings tell what the energy performance of a building is, but if the energy performance of a building is to be ...
Current forecasts call for solid growth in world energy use over the next 20 years, potentially increasing 60% above current energy ...
There are only a few compulsory energy efficiency programs aimed at industrial facilities. It is only recently that the EU introduc ...
The amount of energy consumed in the commercial sector often must be estimated as a fraction of energy use in the combined resident ...