In these regenerators the heat energy transfer between primary and secondary fluid is primarily by radiation and its installation is always done in a vertical stack.This type of exchange is strongly favoured by temperature, so that these retrievers are especially suitable in the following cases: (more…)

As a result of high and rising costs of fossil fuels and fossil fuels affect global environment concern , and by the reduction of greenhouse effect gases from burning causes (Kyoto Protocol), the heat recovery gain importance growing. A heat exchanger absorbs a significant portion of the heat energy of the gases generated during combustion of solid fuel, liquid and gas in the smelting process, heating, roasting, and drying. (more…)

It is of interest to examine potential sources of greenhouse gases sources or atmospheric CO2 by analysis of the global distribution of carbon in all its forms. Atmospheric carbon, which can be assumed to be essentially all in the form of CO2 (i.e., 700 Gt carbon equals 2570 Gt of CO2) comprises only about 1.6% of total global carbon, excluding lithospheric carbon. Obvious greenhouse gases sources of direct or indirect additions of CO2 to the atmosphere are therefore fossil fuel deposits, since portions of them are combusted each year as fuels, and terrestrial biomass. (more…)

Fuel efficiency gains due to technological and operational change can mitigate the influence of growth on total emissions. Increased demand has historically outpaced these gains, resulting in an overall increase in emissions over the history of commercial aviation. The figure of merit relative to total energy use and emissions in aviation is the energy intensity (EI).

When discussing energy intensity, the most convenient unit of technology is the system represented by a complete aircraft. In this section, trends in energy use and energy intensity are elaborated. In the following section, the discussion focuses on the relation of energy intensity to the technological and operational characteristics of an aircraft.

Reviews of trends in technology and aircraft operations undertaken by Lee et al. and Babikian et al. indicate that continuation of historical precedents would result in a future decline in energy intensity for the large commercial aircraft fleet of 1.2–2.2%/year when averaged over the next 25 years, and perhaps an increase in energy intensity for regional aircraft, because regional jets use larger engines and replace turbo- props in the regional fleet. When compared with trends in traffic growth, expected improvements in aircraft technologies and operational measures alone are not likely to offset more than one-third of total emissions growth. Therefore, effects on the global atmosphere are expected to increase in the future in the absence of additional measures. Industry and government projections, which are based on more sophisticated technology and operations forecasting, are in general agreement with the historical trend.

Compared with the early 1990s, global aviation fuel consumption and subsequent CO2 emissions level could increase three-to sevenfold by 2050, equivalent to a 1.8–3.2% annual rate of change. In addition to the different demand growth projections entailed in such forecasts, variability in projected emissions also originates from different assumptions about aircraft technology, fleet mix, and operational evolution in air traffic management and scheduling.

We shows historical trends in energy intensity for the U.S. large commercial and regional fleets. Year-to-year variations in energy intensity for each aircraft type, due to different operating conditions, such as load factor, flight speed, altitude, and routing, controlled by different operators, can be 730%, as represented by the vertical extent of the data symbols. For large commercial aircraft, a combination of technological and operational improvements led to a reduction in energy intensity of the entire U.S. fleet of more than 60% between 1971 and 1998, averaging about 3.3%/year. In contrast, total RPK has grown by 330%, or 5.5%/year over the same period.

Long- range aircraft are B5% more fuel efficient than are short-range aircraft because they carry more passengers over a flight spent primarily at the cruise condition. Regional aircraft are 40–60% less fuel efficient than are their larger narrow- and wide-body counterparts, and regional jets are 10–60% less fuel efficient compared to turboprops. Importantly, fuel efficiency differences between large and regional aircraft can be explained mostly by differences in aircraft operations, not technology.

Reductions in energy intensity do not always directly imply lower environmental impact. For example, the prevalence of contrails is enhanced by greater engine efficiency. NOx emissions also become increasingly difficult to limit as engine temperatures and pressures are increased—a common method for improving engine efficiency. These conflicting influences make it difficult to translate the expected changes in overall system performance into air quality impacts. Historical trends suggest that feet-averaged NOx emissions per unit thrust during landing and takeoff (LTO) cycles have seen little improvement, and total NOx emissions have slightly increased. However, HC and CO emissions have been reduced drastically since the 1950s.

For years it was out of desperation that observers have advised and viewed of American energy policy and geopolitical risks regarding American obsession with oil. United States have become very sensitive to permanent events in the Gulf region. But the great surprise was the American public seems quite happy to give thousands of young soldiers in a desert war against other nation with huge cost inline. (more…)

You know where to insulate, but there’s still one more thing you need to know about—vapor barriers. Well-insulated attics, crawlspaces, storage areas, and other closed cavities need to be well ventilated to prevent excessive moisture build-up. (more…)

Steam heating is an absolutely wonderful method to heat your home. Steam heat is always driven by steam produced from water in a pot of natural gas, oil and electricity. Then it draws through pipes and radiators and heat exchangers to heat your house or residential. Boiler is used to generate steam from water. When the water boils, steam rises through pipes to radiators to heat. Then, the hot radiators play its role to warm the house. (more…)

If water is put on the floor on a cleaning operation, it tends to dry rapidly after a short time. In this position, we say that the water evaporates. Basically what happened is this means that changes in water levels from liquid to gas or steam. Evaporation occurs when molecules escape the surface of a liquid when they have enough kinetic energy to go off from the body of liquid. (more…)

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 the condition of your insulation often enough to keep the insulation from becoming seriously deteriorated. This measure summarizes what insulation does, what to insulate, and how to insulate. It also gives you several methods of finding defective insulation, even if it is buried. (more…)

Since preindustrial times, ambient concentrations of the greenhouse gases have exhibited substantial increases, inter alia CO2 by 30% to about 360 parts per million (ppm), CH 4 by 145% to more than 1700 parts per billion (ppb), and N20 by 15% to more than 300 ppb. The growth rates in the concentrations of these gases in the early 1990s were lower than predicted; while subsequent data indicate that the growth rates are comparable to those averaged over the 1980s. (more…)