Solar Energy in the Aviation Aspect - Term Paper Example

Solar Energy in the Aviation Aspect Student’s Name: Institutional Affiliation Date Assignment is Due: Abstract Solar energy has been an area that has interested numerous disciplines and areas of research. In the solar aviation industry there have been major advancements especially since the 1970s. This paper will examine the use of solar energy in the aviation aspect. The beginning will be a historical background and overview of the starting point of the use of solar energy in aviation. The various experiments, developments and events in the development of solar powered aircrafts will be mentioned. The next part of the introduction will focus on the use of solar energy in lighting systems at airports with safety being cited as the most significant reason for this development. The development and factors to consider when making aircrafts will be examined by methods of string energy mentioned. In addition, the lighting systems that can be utilized will be evaluated with various studies about the use of solar energy in lighting and aircraft powering being examined, the conclusion will cite solar energy as the next step in aviation advancement. Introduction Solar aviation Solar aviation has been an ongoing effort of experiments, developments and discoveries. It set off with milder models somewhere in the 1970s at the time when solar cells that were affordable made an appearance in the market. However, it was until the 1980s when the very first human flights were developed. Paul MacCready's and his team (from the United States) developed an aircraft that came to be known as the Gossamer Penguin that paved the way for another development called the Solar Challenger (Solar impulse, 2011). The aircraft had a power of 2.5 kW that was its maximum and managed to cross the Channel in 1981 and endured more short distances in succession. On the other side, in Europe, almost at this time, Günter Rochelt first began making flights using the Solar 1 that had been fitted with about 2500 photovoltaic cells whose function was to generate about 2.2kW. Come 1990, Eric Raymond, an American, went across the United States with a Sun seeker over a period of around 2 months with 121 hours of flying. This was covered in a total of 21 stages. The longest time he stayed in the air was for 400 kilometers. His aircraft was a solar motor bike-sail plane (Solar impulse, 2011). A competition in the mid 1990s called the Berblinger was held where the participants were challenged to build aircrafts that would have the ability to climb an altitude of about 450m using only energy from batteries and solar energy of 500W/m2. They were also meant to be in a stable horizontal flight. In 1996, a professor Voit-Nitschmann and his team, Stuttgart University, won the competition using an aircraft (Icaré II) that had a wingspan of 25 meters that had been fitted with solar cells of 26 m². Another record was set by the Helios, which was developed for NASA by the American company AeroVironment. It was controlled using a remote and had not pilot. It had a 70 meter wingspan. It got to an altitude of 30 000 metres in 2001 (Solar impulse, 2011). Aviation lighting Aviation technologies and modifications are growing at a very rapid rate. As at now, there are over 18,000 areas of landing in the United States (US). The aviation industry in the US serves over a 600 million people every year. Technological solutions that have been adopted up till now are serving to meet the needs and problems that arise as the number of people using the system keep increasing. There have been initiatives such as the airports technology program (ATP) have been developed by the FAA in order to address needs that may arise in the aviation industry. The main goal of numerous airport systems is to ensure that the advancements that are made to their systems are effective so as to reduce or completely get rid of accidents of aircrafts while at the same time keeping the costs of maintaining and running these airports low (Energy control systems, 2009). One of the areas that when polished will lead to smooth and safe running of airports is the communications systems. Communication in this sense is not restricted to the technology used within the airplane but extends wider to the system used to communicate between the airport controllers and the pilots. There is need to improve the familiarity that pilots have to airstrips. The National Safety Transport Board (NTSB) has made recommendations to airports to include visual guidance devices and systems that will give warning when required and guide the planes. Following the increase of incursions on runways between 2001 and 2004, NTSB reinforced their recommendations for the inclusion and implementation of safety systems on the ground that give a direct warning to pilots and other crew. In order to improve safety in airports, there is need to input systems that are most effective and reliable at all times. One of the methods that can be employed to make this happen is the use of solar energy to supplement the energy requirements at airports while at the same time maintaining a cost effective project. Solar aircrafts The design of a solar airplane should be thought out carefully and with an open global mind, that will analyze it as a multifaceted system that contains many other subsystems that are dynamic in nature, which keep exchanging energy continuously. Also they have to keep in mind the common challenges that must be met and dealt with, for the solar powered aircraft. The material and structures should be made in such a way as to collect solar energy to the maximum (Vineet, Kumar & Shashi, 2011). Factors that will affect how this energy is collected should be considered and they include: Location of the plane’s operation, that is, geographical area, latitude Inclination and orientation of the solar cell area in relation to the general horizon Weather conditions like the humidity, clouds and temperature Utilization and collection of energy The period of the year and what time of day it is The payload Design of the plane Mission intended Altitude Another factor that indirectly affects solar powered aircrafts is the wind. It does not affect the ability of the aircraft to generate power but, it has quite an effect on its efficiency aerodynamically. It also has an effect on how the aircraft consumes power which might limit its efficacy. The aerodynamics includes the solar airplane having wings that are constituent of the part that lifts the plane. When in steady and stable flight, airflow that results from the aircrafts’ speed leads to the creation of two forces: one is the lifting power that stabilizes the aircraft when it’s airborne and while covering the drag and the weight that are compensated for by the propeller’s thrust (Vineet, Kumar & Shashi, 2011). The solar panels, constituent of solar cells linked in a particular configuration, cover a certain surfaces on the wing or also, possibly other parts of the aircraft like fuselage or tail. Sometimes, in the day, with dependence on the elevation and irradiance of the sun, they convert the available light to electrical energy. The converters in the planes ensure that the fitted solar panels optimally working at collecting energy (Vineet, Kumar & Shashi, 2011). Source: Noth, A., Siegwart , R &Engel, W. (2007). Design of Solar Powered Airplanes for Continuous Flight, version 1.1. 1-17. Retrieved on June 3 2011, from http://www.sky-sailor.ethz.ch/docs/Conceptual_Design_of_Solar_Powered_Airplanes_for_continuous_flight2.pdf Solar energy in lighting Solar energy has been documented as one of the most reliable sources of energy in the world. The US department of energy has recommended solar energy because, it is independent of restraining factors like power outage, failure of grids, and loss of lines, constant schedule maintenance, and failure of cables, replacement of cables, system failures and rising costs of energy in the world’s economy. Since 2002, FAA has been evaluating the possibilities of using solar LED lighting. A revision in 2004 affirmed that the technology was available for use. These runway lights are portable to promote ease of use. The acceptance of solar energy has made its incorporation into other areas possible (Zegger- Murphy, 2007, p. 1-14). There have been major advancements in the field of technology that have made it possible for solar energy to be used as a solution for the energy problems that are encountered by airports in their airfield operations so as to make the safety measures better at lower costs. However, these advancements and changes in technology have not been completely approved by the FAA yet. The only lighting option that was available before was hardwired electric systems but with newer methods of harnessing renewable energy being developed, LED lighting systems are utilized with an added advantage of being more powerful and reliable. These systems are already in use in many defense and commercial airports in the world. The LED lighting systems are as bright and as powerful as the electric systems giving them an almost equal opportunity for competition (Zegger- Murphy, 2007, p. 1-14). Light emitting diodes (LEDs) are not a new filed in technology. They have been in use for over thirty years. Their prominence in the agenda of the lighting industry has only been popularized since 2002. LED is now respected and considered a viable option for lighting. The use of this lighting system in airport systems will has served as one of the greatest changes in the visual aid field since the 1920s. The use of LEDs for solar power is most suitable because of their low consumption of power, owing to their relatively reduced voltage requirements. The most essential components and requirements for an effective lighting system are durability, brightness and visibility (Zegger- Murphy, 2007, p. 1-14). Solar LED runway guard lights Also referred to as (ERGL) solar LED elevated runaway guard lights are lighting systems that operate in two system methods. They contain an approved housing made of metal, and approved by the FAA. It also, supported by an energy management system for solar power that is self contained and inclusive of 20 watts in energy. Reflective markers have been utilized in runway fields before and are still used now. However, they have a limitation because of their dependency on other light, in order to be visible. Their passive nature of lighting is a barrier to them being effective in their use, in applications for marking runways. Other than their passiveness, there are other limitations that are presented by reflective lighting systems (Zegger- Murphy, 2007, p. 1-14). One of them is that, their efficiency and brightness is dependent on how well the aircraft lights will hit them. They have to be placed unmistakably on the markers, if adequate lighting is to be achieved. This is especially risky if the pilot is not in line with the markers that have been placed on the runway. In addition, the lights could be dim in case the aircraft lighting is not as bright as needed. Also, there are necessary operations that he aircraft must perform at the runway that could raise the level of risk. For instance, when the plane is turning, they may not be able to illuminate the markers creating a dark spot on the runway which is quite dangerous (Zegger- Murphy, 2007, p. 1-14). As the markers age at the airfields, their quality diminishes because they are worn down by weather, sand blast, chemicals and also because of the life cycle that the products have. Most of the wearing down happens to the metallic surface of these reflectors (Zegger- Murphy, 2007, p. 1-14). As the quality of the product diminishes, the performance does to which may result in dim lighting that may not be adequately visible to aircrafts presenting a major risk to them, especially when landing. Technologies that are used on taxiways are runways should never fail because the results can be catastrophic. Another risk that is posed by reflectors is that when it snows, the snow could stick on their surfaces making them ineffective of effective at a very poor level. However, the greatest disadvantage that reflective lighting systems pose is that they have no ability to illuminate themselves at night. Following the many disadvantages and risks that are posed by using reflective markers, the solution that is needed should be more effective, self sufficient, self dependent, energy conscious and of relatively lower costs. This solution can be found in ERGL systems (Zegger- Murphy, 2007, p. 1-14). Though their consultation processes, engineering and design will incur significantly higher costs in terms of disrupting the running of the airport for some time, hiring construction crews and putting in new material for construction and, in general, installing the system; they will offer the airfields an alternative solution to problems such as reliability, operation effectiveness and being cost effective. However, there is still a debate as to a whether the system will effectively address the problems that are experienced with safety in by reducing the number of runway incursions with immediate effects. This technology has not been completely approved for filed use by the FAA, but, ERGL present airport controllers with an effective way to ensure that pilots are alerted of approaching runways well before they get to it in the case when an electrically hardwired power solution is unavailable. As of now, this solution is ideal for use at small or medium sized airports as safety precautions but not to be fully operational on their own as runway markers. They are also utilized as supplements to the already existing lighting systems at the airstrips used for marking runways (Zegger- Murphy, 2007, p. 1-14). Solar LED ERGL systems provide airstrips with a 24 hour amber beacon that flashes continuously at times when there is poor visibility, or during the night of conditions that mimic night time like some times when there are storms. International research done at airports indicates that an ERGL system that is operational adequately and effectively significantly reduced the number of incursions at runways by lowering the risk of this happening. Pilots and car operators at the airport are provided with a clear visual guidance to give them direction as to where each of them should go (Zegger- Murphy, 2007, p. 1-14). The ERGL does not need an external source of power because, in operates by utilizing the solar charged batteries that have been incorporated to its hardware system. They are also able to alter their operational competencies, in terms of being bright, medium or high requirements of light brightness. The hardware design of the ERGL consists of energy management system, solar panels and battery systems that are housed in a solar engine. This type of design makes it possible for the ERGL to be used, in almost all solar environments depending on the candela outputs that are required (Zegger- Murphy, 2007, p. 1-14). Another advantage that these LEDs have is that they are devices that require relatively lower voltages that have been made to be naturally suited for solar power. As a result, solar power is able to provide the LEDs enough power to drive their functioning to the optimum levels with the highest level of efficiency that can be managed. The LEDs operate in such a way that there is a balance between when the battery will require charging and when they will be replaced. The major goal of developing the ERGL system is so that it could be unmistakably noticed by pilots so as to warn them of any dangers and potential incursions, if any are expected. Reviewing the functioning of the ERGL, it has been effective in fulfilling its goal and purpose (Zegger- Murphy, 2007, p. 1-14). The ERGL technology is currently being tested by the FAA at the William J Hughes Technical Center. They have the potential of providing airports with a system that will provide a permanent and fully functional and approved solution for visual guidance in medium sized airports. When the system was tested, it was deduced that LED ERGL systems have the ability of providing lighting that was crisper, more saturated and brighter light than the incandescent systems of electrical hardwired systems. The brightness systems are of 30% output which is an equivalent of the 100% output of the incandescent lighting systems. The observers of the testing noted that the LED sourced lights are provided with a brighter output which results in better situational awareness when it comes to identifying the location of the runways. Overall, the assessment was that LED lights were judged as being more conspicuous and as providing a relatively and significantly better situational awareness (Zegger- Murphy, 2007, p. 1-14). An additional advantage to LED ERGL lighting systems is that they can be controlled wirelessly giving the control tower more control when it comes to activating the ERGL when the aircrafts are at the airport or at the airfield. Thus, ERGL can be run in a specialized manner for special operations and they can also run at higher levels of intensity since they are utilized when required and so the control tower can increase intensity when required from their towers so that when the need is not so much, they can be switched to lower intensities (Zegger- Murphy, 2007, p. 1-14). For instance, if there is an aircraft approaching the airstrip when it’s dark, the intensity of the lights on the runway can be raised in intensity making them brighter while the lights at the taxiway can be maintained at a medium level. In order for the technology solar ERGL to sell in the market today, there is need for them to incorporate the existing systems that will help in power management in order to keep battery levels at a regulated level and power output at the same level too. With this regulation, the system can function more effectively. One of the technologies that can be used for this is energy management system (EMS) (Zegger- Murphy, 2007, p. 1-14). Solar ERGL with supporting EMS (energy management systems) It is vital for LED technologies to include technologies for regulation and general management of power in to their systems like ERGL. By making use of special customized software and electronics, technology for power management can be designed so as to be part of the solar LED ERGL technology. The main aim of doing so would be to optimize the charging of the batteries during the day by maximizing use of the amount of solar power that is available during the day by responding and adapting to the environment in which it exists. This strategy is very effective in ensuring that the power available is used to its full potential an as a result, making the performance of the product be at an optimum level in terms of extending the life of the battery and making it a reliable alternative (Zegger- Murphy, 2007, p. 1-14). By employing power management technology, some of the solar LED technology can function for up 200 hours after one round of charging. Managing power of these technologies leads to long autonomy. The autonomy of a solar powered product refers to the calculation that has been done about how long the product will last when it is not being charged directly by solar power. The more advanced the management system being used, the more efficient and autonomous the product will be. If the management system is highly advanced, the working of a solar LED ERGL may last up to 20 days with the system as a whole requiring no scheduled maintenance for about 5 years (Zegger- Murphy, 2007, p. 1-14). The initial stage of the power management is deployed by the system creating a connection that is direct between the batteries that will be utilized and the solar panels themselves. This is the enabling power of achieving as much charging as has been made possible during the day. The next and final stage of the use of power management systems is when the batteries have reached their optimal floating charging level. At this stage, the system will switch to a voltage charge mode where only power that is needed at the time is received from the solar creating a direct flow between what is used and what is gained leaving the charge of the battery at an optimum level until the use of LED is triggered or activated. With the storage of power and optimum energy, when the LED lights are activated, the resulting effect is very bright and adequate light that is sure to last through the night without any of the expected glitches (Zegger- Murphy, 2007, p. 1-14). Another feature that is available in the power management systems is that they have provisions for low battery cutoffs which assist in preventing damage in the event that the battery goes for a long time without receiving adequate charging. Another technology that can be incorporated is the automatic light control (ALC) which manages the products light. It controls the output based on information from the storage levels, power available, location of installation and the climatic conditions at the time. Much as these solar powered technologies provide a most viable option, they have to be designed while keeping in mind the very worst solar conditions that may occur. This means that they should be designed to work even during the winter and this presents inefficiency (Zegger- Murphy, 2007, p. 1-14). Practically, this implies that each technology needs to be designed to operate with maximum reliability even during the time when there is winter at its worst. This is the time when the availability of solar ambient light to be utilized for recharging is at a very low level. The result of incorporating a design that will see to this is that during the months when the light is available with maximum abundance, the solar charging unit is overqualified for its current functions and operating in an inefficient, as it does not use much of the material that have been installed for the winter month. Another problem may arise because every unit is meant to be customized specifically since the performance level is meant to be adjusted to the level and amount of energy that is available at the location of installation (Zegger- Murphy, 2007, p. 1-14). For instance, an airport solar unit that has been installed in a place like Egypt, where plenty of sunlight is available for about six hours as a daily average, will be designed to accommodate the same performance intensity as a solar unit that has been installed in an airport in Patagonia, that experiences a mere hour of sunlight everyday as an average. The Egyptian unit will be operational at an inefficient level as a good level of its environment’s solar energy goes to waste as there is no provision to store it. This problem can be solved by making use of the ALC which adjusts the unit to the prevailing conditions making it adapt to the environment and avoiding inefficient operation of the unit in some areas while maximizing its potential (Zegger- Murphy, 2007, p. 1-14). Solar energy for aircraft powering The development of a functioning solar powered aircraft with the capability of nonstop flight has been a dream up till a few years ago. Today, this great task has become feasible and plausible. Very significant progress has been made recently in the further development of flexible solar cells, batteries with high energy density, more powerful processors, and CMOS and MEMS sensors have been made into smaller models (Noth, Siegwart & Engel, 2007, p. 1-17). The idea works by a simple set of technological concepts. The aircraft is fitted with solar cells that cover its wings. From these cells, it recovers energy from solar power and utilizes it to supply the equipment in the craft with power like the system that propels it, other electronic devices and to charge the available battery so as to store surplus energy. In the night, the battery energy is the only energy source that is utilized at a relatively slower rate before morning when the charging begins again (Noth, Siegwart & Engel, 2007, p. 1-17). There is still an enormous amount of research and development that needs to be done, in order to merge knowledge from technological and other disciplines. This is necessary to integrate the knowledge on concepts and advancements in technologies, to develop a fully operational system. The most challenging issue is not what to do, but how to do all that is required for optimal functioning. Like the merging and installment of the different material and parts to ensure that the criterion needed are met (Noth, Siegwart & Engel, 2007, p. 1-17). An example of a flight attempt is the Sky-Sailor project developed in 2004 at the EPFL/ETHZ Autonomous Systems Lab following a contract they signed with the European Space Agency. The foals of the project were to the study how the realization of a fully autonomous solar aircraft in the domains of generation of power and navigation can be made into a reality (Noth, Siegwart & Engel, 2007, p. 1-17). From the project, a global schematic and methodology was developed from the specifics of the design of airplane. The first prototype they were applied to showed that they can be made to be extremely useful, highly efficient and quite accurate. The major benefit that the design of the plane has is that its specifics are generalized such that they can be applied to other planes being developed regardless of their sizes and models from those of large scale and high altitude platforms to others (Noth, Siegwart & Engel, 2007, p. 1-17). The method used for the design is analytical which allows for the clear identification of the general principles that other people following the design should take note of, like wing surface density constancy. The overall finding of the study of the project was that there was proof that realization an airplane powered by solar energy to full flight is possible but somewhat more difficult for aircrafts of relatively high dimensions (Noth, Siegwart & Engel, 2007, p. 1-17). Recommendations ALC (automatic light control) ALC software can be used by Solar LED units to help automatically adjust their immediate light output in relation to the prevailing weather and solar conditions. An ALC works by utilizing a type of control system to examine and evaluate the level of charge received by its batteries throughout the day from the solar panel. By using a software algorithm to evaluate the processes, the ALC will make note of any trends that are visible in the battery voltage levels in order to develop an approximated comprehension of the relationship between its installation location and the existing weather and solar conditions (Zegger- Murphy, 2007, p. 1-14). After getting this information, it makes a determination of the solar conditions that are required to maintain the specific light output. If the prevailing condition do not relate, it determines whether there should be dynamic adjustments made to the output levels so as to ensure that the battery levels will remain at optimal levels for highly autonomous operation. Products that incorporate this configuring ability function reliably at almost any location on earth. To widen the field of solar power use in aviation, lighting systems are not the only areas where solar energy can be harnesses for use, another area is the use of this solar energy to power aircrafts and fly them on this energy source alone (Zegger- Murphy, 2007, p. 1-14). Battery technology to use Selecting a Battery is the most vital matter for a solar powered airplane that is autonomous as it represents the most significant part of the total mass of the craft. The advancements that have been made in solar cell and battery technology will lead to a self sustaining long period flight for planes. One of the aircrafts trying this out is the Solar Impulse which is an experimental, manned craft that is powered by the Sun only. The designers are still facing some tough challenges. One is that they need to find a way for storing enough energy to make flight at night and balancing the entire plane’s size which is difficult. These energy and weight needs should be met. The efforts that are being made so far will result in a viable plane soon; probably within a few years (Vineet, Kumar & Shashi, 2011, p. 2051-2057). As at now, the highest level in energy ratio for a rechargeable battery is about 200 wh/kg (Lithium Polymer technology). The most utilized are photovoltaic cells which are devices that function by converting energy provided in solar form into electric form using a photovoltaic effect. Solar cells are composed of various semiconducting materials, constituting one or more layers. As sunlight hits the surface of the solar cell, it creates a charge that then carries them as holes and electrons. Then, an internal field that is produced by junction, does the separating of some positive (holes) from the negative (electrons) charges. Holes get swept to positive ones and vice versa with the positive electrons (Vineet, Kumar & Shashi, 2011, p. 2051-2057). After this has happened, in case a circuit is created, the electrons that are free pass through the entire load as they attempt to recombine and if they are illuminated, a current is then produced. There are varying kinds of photovoltaic cells that are sorted according to the kind of material they have been made with, the process used in their fabrication, their substrates. However, the most common and widely used material is silicon. Within the silicon, further distinguishing can be done using the crystal type (Vineet, Kumar & Shashi, 2011, p. 2051-2057). The different crystals are: Monocrystalline, semiconducting and pure material is utilized and it gives a higher efficiency which is accompanied by a higher cost Polycrystalline that is constituent of crystal structures that vary in size. It is cost efficient but with less efficiency in functioning of solar cells. Amorphous cell. Here, a silicon film is put on glass or any substrate material, including flexible ones. This layer’s thickness is less making the production costs less too. However, it is less efficient too. Energy Storage Solar energy is not constant and it is also not continuous. Thus, there is need to come up with ways to store the energy for later use (Vineet, Kumar & Shashi, 2011, p. 2051-2057). This can be done using: Chemical methods like biofuels and hydrogen Electrochemical methods like fuel cells and batteries Electrical methods like supercapacitors, capacitors and SMES Mechanical methods such as flywheels and compressed air Thermal methods Conclusion Numerous solar powered aircraft experiments and prototypes have given the required proof that an aircraft can take flight aided by solar power as the sole source of energy. Solar energy can be used in many aspects of aviation. There is the direct use of solar energy to power airplanes and also in the indirect aspect of supporting aircraft supporting operations like in the operation of runways and airports. Runway safety has been identified as the most challenging field in airport safety. The solution for this does not need to be complex since it can be as simple as having a solar powered system incorporated into the running. The solar LED and ERGL systems are the most developed and systems so far and they should be used. Solar power should be the next step in aviation. References Primary source Zegger- Murphy, C. (2007). Visual Guidance: Solar Led Aviation Lighting And Solar Power Systems Technology Solutions. 2007 FAA Worldwide Airport Technology Transfer Conference. 1-14. Retrieved 3, June, 2011, from http://www.airporttech.tc.faa.gov/NAPTF/att07/2007/Papers/P07085%20Zegger-Murphy.pdf 2000 FAA National Aviation Research Plan. (2002). 2.2 Airports Technology Program, Retrieved 3 June, 2011, from http://204.108.5.10/nasiHTML/RED/red98/2-2.html Berry, P. (2000). The Sunriser - A Design Study in Solar Powered Flight. World Aviation Conference, San Diego, USA. Dudenhoefer, J. & George, P. 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