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 air, but which is somehow being sustained in the air. This is due to the airflow over the airplane. This airflow exerts a lift force which counteracts the weight of the airplane and sustains it in the air—a good thing. The airflow also exerts a aerodynamic drag force on the airplane which retards its motion—a bad thing. The drag must be counteracted by the thrust of the engine in order to keep the airplane going. The production of thrust by the engine consumes energy. Hence, the energy efficiency of the airplane is intimately related to aerodynamic drag. This is just one of many examples where the disciplines of aerodynamics and energy interact. (more…)
One of the most important aerodynamic effects on energy consumption required to keep a body moving through a fluid is the aerodynam ...
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 ...
In contrast to electromagnetic suspension systems, electrodynamic suspension systems can provide stable suspension without a feedba ...
The comfort heating system in a building brings itself to the concept of complete heating operating unit. In order to work prop ...
Oceanic heat flow data show a clear variation with the age of the lithosphere. Values greater than 100 mW m –2 occur near the r ...
The word “laser” is an acronym for “light amplification by the stimulated emission of radiation.” Lasers of all kinds consist of several basic components: an active medium, an outside energy source, and an optical cavity with carefully designed mirrors on both ends. One of the mirrors is 100 percent reflective while the other is somewhat less reflective, so a beam can be emitted. The active medium is inside the optical cavity and is excited with an external energy source (typically electricity). For the cavity to emit laser radiation, the active medium has to achieve an unusual energy state called “population inversion.” (more…)
The first known laser was made by Theodore Maiman at Hughes Research Laboratories in Malibu, California, in 1960, but the seeds ...
Different lasers use different materials as the active medium. The medium can be either solid, liquid, or gas, and there are ad ...
There are literally thousands of uses for lasers. One of the largest applications is telecommunications—sending a signal throug ...
It is known that laser printers print faster, but swallow a large amount of energy, even if the printer is in the energy saving ...
Fabrication techniques developed for integrated circuit (IC) production have been refined to the extent of supporting a multi-b ...
The idea of using an absorption fluid as a refrigerant carrier derived from the drawback of VCR (vapor–compression refrigeration) systems that the gas compression requires a high work input. A pump that requires practically no work to increase the pressure in the refrigeration system replaces the complicated and work-consuming compressor. There are two major advantages of absorption refrigeration systems (ARSs) compared with VCRs (vapor–compression refrigeration): No CFCs or HCFCs are used as refrigerants, and they use heat from different sources, such as combustion, industrial processes, waste heat (an economical solution for recovery), or solar heat. (more…)
Heat-actuated heat pumps are cooling systems requiring no electricity for operation. Rather, a heat source is used, avoiding the ne ...
The term cryogenics derives from the Greek kryos, for icy cold. The upper limit that characterizes the cryogenic region of the temp ...
Separation is a unit operation used in absorption heat pumps and chemical processing applications such as solvent extraction and pr ...
Active solar hot water systems water are usable with air, liquid, vapor or liquid collector fluid or gas to liquid process. Hot ...
Micro technology can be employed to produce miniaturized refrigeration and cryocooling systems. Although process intensificat ...
All electromagnetic suspension-based systems employ some type of feedback control mechanism to maintain stable levitation. (An interesting exception to the above rule, which has been demonstrated in the laboratory, consists of a permanent magnet suspended below a block of high-temperature superconducting material held below its critical temperature. Stable suspension results from a property of the superconducting state that immobilizes magnetic field lines in the superconducting material.) (more…)
In contrast to electromagnetic suspension systems, electrodynamic suspension systems can provide stable suspension without a feedba ...
Electromagnetic Suspension (EMS) system in which an array of magnets is attracted upwards to a steel rail. It is possible to de ...
A propulsion alternative is to transfer power to the vehicle and then have a magnetic structure on the vehicle that can create ...
Electrodynamic Suspension (EDS) can be viewed as an array of magnets moving over a conducting sheet and being pushed upwards by ...
High-speed maglev technology offers four main advantages: non-contact operation; low-mass vehicles (on a per seat basis, maglev veh ...
Energy is consumed by various segments of the economy, including households, commercial establishments, manufacturing enterprises, and electric power generators. Only a portion of total energy demand is sensitive to temperature changes. (more…)
Here, the sensitivity of energy demand to climate is measured two ways. The first method uses elasticities that provide simple summ ...
To determine the effects of past climate trends on global energy consumption, the econometric equations providing the degree day el ...
Establishing the impact of climate change on energy demand requires a measure of heating and cooling requirements. In the United St ...
Although the focus of many policy studies of climate change is on establishing the causal links between anthropogenic systems, emis ...
Climatologists generally agree that there is accumulating evidence that a warming trend has been occurring since the mid-1960s. The ...
The pace of innovations in batteries has not matched the remarkably fast evolution in the development of portable electronic technology. Batteries are widely regarded as the weak point slowing the rapid innovations in portable technology. Chief among consumer complaints are that batteries do not last long enough and that they do not last as long as the manufacturer claims they will. (more…)
After lighting, personal computers (PC) and monitors have the highest energy use in office environments. Studies have shown tha ...
A fuel cell is an electrochemical device that combines hydrogen with oxygen to generate electricity, heat and water to produce. ...
The wind has covered every Sunday morning more than 50 percent of electricity & energy demand. It has also achieved the record high ...
Take a look at the following energy saving ideas and new green products and see how many you can use to save your hard earned c ...
Establishing the impact of climate change on energy demand requires a measure of heating and cooling requirements. In the United States, this measure is a degree day, which is defined in terms of an absolute difference between average daily temperature and 651F, which is an arbitrary benchmark for household comfort. Commercial heating degree days are incurred when outside temperatures are below 651F, generally during the winter heating season from October through March. (more…)
Here, the sensitivity of energy demand to climate is measured two ways. The first method uses elasticities that provide simple summ ...
To determine the effects of past climate trends on global energy consumption, the econometric equations providing the degree day el ...
Energy is consumed by various segments of the economy, including households, commercial establishments, manufacturing enterpris ...
Although the focus of many policy studies of climate change is on establishing the causal links between anthropogenic systems, emis ...
Climatologists generally agree that there is accumulating evidence that a warming trend has been occurring since the mid-1960s. The ...
Here, the sensitivity of energy demand to climate is measured two ways. The first method uses elasticities that provide simple summary measures of how departures from normal temperatures affect energy consumption. The second approach, reported in the following section, uses econometric simulation to estimate how climate changes affect energy demand. (more…)
To determine the effects of past climate trends on global energy consumption, the econometric equations providing the degree day el ...
Establishing the impact of climate change on energy demand requires a measure of heating and cooling requirements. In the United St ...
Energy is consumed by various segments of the economy, including households, commercial establishments, manufacturing enterpris ...
Climatologists generally agree that there is accumulating evidence that a warming trend has been occurring since the mid-1960s. The ...
Although the focus of many policy studies of climate change is on establishing the causal links between anthropogenic systems, emis ...
The comfort heating system in a building brings itself to the concept of complete heating operating unit. In order to work properly, a heating system must utilize in different of serving pieces and function. This includes such as control function, energy source, a load device, and something that will indicate or record the level of heat energy produced. (more…)
If a space is occupied on a predictable schedule, you can use either timeclocks or setback thermostats to turn the conditioning ...
Heat has a enormous influence in our daily lives. Heat quantity exposed in our live has related to the foods we eat, the temper ...
HVAC (heating, ventilation, and air-conditioning) systems vary depending on the complexity of room units size from single rooms ...
Steam heating is an absolutely wonderful method to heat your home. Steam heat is always driven by steam produced from water in ...
Active solar hot water systems water are usable with air, liquid, vapor or liquid collector fluid or gas to liquid process. Hot ...
In today’s times staying in a budget is very important. So doing maintenance to certain things yourself can be a good way to stay within that budget. There are some simple ways to clean your heating and air - conditioner vents. Doing simple cleaning and inspecting your vents can be a great way to help the air quality in your home better and improve the heating and cooling in your home. (more…)
Don't sweat it out when you don't have to. Got your A/C running and still feel warm? Here are some tips that will help keep you ...
Moisture movement into exterior walls". Any where air can move, so too can water in the form of moisture molecules. Traveling via a ...
HVAC (heating, ventilation, and air-conditioning) systems vary depending on the complexity of room units size from single rooms ...
In many existing buildings, the only economical way to improve the thermal resistance of the roof is by having insulation insta ...
Exposure to air pollutants and air pollution problem are very high in indoor environments in developing countries. Smith has es ...