Solar air heaters are simple device to heat air by utilizing solar energy and employed in many applications requiring low to moderate temperature below 60ºC, such as crop drying and space heating. In a solar air heater, the fins or obstacles located in flow area increases the heat transfer coefficient and output temperature of air. Accordingly, collector efficiency increases too.
This paper presents an experimental energy and exergy analysis for a new flat plate solar air heater (SAH) with several obstacles (Type I, Type II and Type III) and without obstacles (Type VI). The measured parameters were the inlet and outlet temperatures, the absorbing plate temperatures, the ambient temperature, and the solar radiation. Further, the measurements were performed at different values of mass flow rate of air (0.0074, 0.0052, 0.0016 kg/s). Solar air heater having free (Tip IV) and fixed obstacles (Tip I, Tip II, Tip III) is compared to flat-plate solar air heater as well as each other in terms of energy and exergy efficiencies and dimensionless exergy loss ratio.
After the analysis of the results, the optimal values of efficiencies (energy and exergy) is Type II of absorbing plate in flow channel duct for all operating conditions and solar air heater (SAH) supplied with obstacles appears significantly better than that without obstacles (Type IV). The results show that the largest irreversibility is occurring at the flat plate (without obstacles, Type IV) collector in which collector efficiency is smallest. At the end of this study, the energy and exergy relations are delivered for different SAH
Thursday, June 18, 2009
Tuesday, June 16, 2009
Renewable Energies in the USA: US: 100 New Nuclear Power Plants by 2030
While solar, wind, and biofuels have been garnering the lion's share of public and political attention in plans to remake the nation's energy portfolio, some nuclear energy advocates, including Senator Lamar Alexander, want more emphasis put on nuclear energy. In a speech last week at Oak Ridge National Laboratory, Senator Alexander called for the nation to open 100 new nuclear power plants by 2030. Do yourself a favor by visiting NPR.org and downloading the first hour of the last Science Friday. I just listened to it after jogging (great weather by the way). A really intelligent discussion of the future of nuclear energy in the US ranged from the waste storage issue to microreactor technology to financing.
Even the geekiest of Green Nerds (I was called a to-be-newborn-solar panel the other day by a colleague) probably needs some time away from green tech talk a few minutes a day, especially with all the slop that is bombarding us these days at checkout counters, in brand campaigns and on the news. So, I know the last thing you want to do is head out for that morning run, pop in the ear buds and have a clean tech podcast as your accompaniment (although it is fun, and seriously, when else would you do it between projects and newsletters and phone calls and emails and ...); but, the conversation here - which included an MIT Prof and former DOE Under Secretary (Moniz), a NRDC egghead (Cochran) and a scientist - is worth your time.
There is some interesting pro-reports out there, like this one:
An interdisciplinary MIT faculty group decided to study the future of nuclear power because of a belief that this technology is an important option for the United States and the world to meet future energy needs without emitting carbon dioxide and other atmospheric pollutants. Other options include increased efficiency, renewables, and carbon sequestration, and all may be needed for a successful greenhouse gas management strategy.
The study examines a growth scenario where the present deployment of 360 GWe of nuclear capacity worldwide is expanded to 1000 GWe in mid-century, keeping nuclear's share of the electricity market about constant. Deployment in the U.S. would expand from about 100 GWe today to 300 GWe in mid-century. This scenario is not a prediction, but rather a study case in which nuclear power would make a significant contribution to reducing CO2 emissions.
The study offers a number of recommendations for making the nuclear energy option viable, including:
* Placing increased emphasis on the once-through fuel cycle as best meeting the criteria of low costs and proliferation resistance;
* Offering a limited production tax-credit to 'first movers' - private sector investors who successfully build new nuclear plants. This tax credit is extendable to other carbon-free electricity technologies and is not paid unless the plant operates;
* Having government more fully develop the capabilities to analyze life-cycle health and safety impacts of fuel cycle facilities;
* Advancing a U.S. Department of Energy balanced long-term waste management R&D program.
* Urging DOE to establish a Nuclear System Modeling project that would collect the engineering data and perform the analysis necessary to evaluate alternative reactor concepts and fuel cycles using the criteria of cost, safety, waste, and proliferation resistance. Expensive development projects should be delayed pending the outcome of this multi-year effort.
* Giving countries that forego proliferation- risky enrichment and reprocessing activities a preferred position to receive nuclear fuel and waste management services from nations that operate the entire fuel cycle.
The authors of the study emphasized that nuclear power is not the only non-carbon option and stated that they believe it should be pursued as a long term option along with other options such as the use of renewable energy sources, increased efficiency, and carbon sequestration.
Even the geekiest of Green Nerds (I was called a to-be-newborn-solar panel the other day by a colleague) probably needs some time away from green tech talk a few minutes a day, especially with all the slop that is bombarding us these days at checkout counters, in brand campaigns and on the news. So, I know the last thing you want to do is head out for that morning run, pop in the ear buds and have a clean tech podcast as your accompaniment (although it is fun, and seriously, when else would you do it between projects and newsletters and phone calls and emails and ...); but, the conversation here - which included an MIT Prof and former DOE Under Secretary (Moniz), a NRDC egghead (Cochran) and a scientist - is worth your time.
There is some interesting pro-reports out there, like this one:
An interdisciplinary MIT faculty group decided to study the future of nuclear power because of a belief that this technology is an important option for the United States and the world to meet future energy needs without emitting carbon dioxide and other atmospheric pollutants. Other options include increased efficiency, renewables, and carbon sequestration, and all may be needed for a successful greenhouse gas management strategy.
The study examines a growth scenario where the present deployment of 360 GWe of nuclear capacity worldwide is expanded to 1000 GWe in mid-century, keeping nuclear's share of the electricity market about constant. Deployment in the U.S. would expand from about 100 GWe today to 300 GWe in mid-century. This scenario is not a prediction, but rather a study case in which nuclear power would make a significant contribution to reducing CO2 emissions.
The study offers a number of recommendations for making the nuclear energy option viable, including:
* Placing increased emphasis on the once-through fuel cycle as best meeting the criteria of low costs and proliferation resistance;
* Offering a limited production tax-credit to 'first movers' - private sector investors who successfully build new nuclear plants. This tax credit is extendable to other carbon-free electricity technologies and is not paid unless the plant operates;
* Having government more fully develop the capabilities to analyze life-cycle health and safety impacts of fuel cycle facilities;
* Advancing a U.S. Department of Energy balanced long-term waste management R&D program.
* Urging DOE to establish a Nuclear System Modeling project that would collect the engineering data and perform the analysis necessary to evaluate alternative reactor concepts and fuel cycles using the criteria of cost, safety, waste, and proliferation resistance. Expensive development projects should be delayed pending the outcome of this multi-year effort.
* Giving countries that forego proliferation- risky enrichment and reprocessing activities a preferred position to receive nuclear fuel and waste management services from nations that operate the entire fuel cycle.
The authors of the study emphasized that nuclear power is not the only non-carbon option and stated that they believe it should be pursued as a long term option along with other options such as the use of renewable energy sources, increased efficiency, and carbon sequestration.
Friday, June 12, 2009
The Benefits Of Using Solar Water Fountains
Do you love water fountains? Get solar water fountains for your garden’s d?cor. You will be mesmerized by the grand elegance of solar fountains. Solar power is the source of energy of these fountains. Previously, solar energy was very expensive. Solar power was earlier only used by big industries or by those who had top-notch devices. Now, the solar panels are not so expensive and these panels are even used for running solar powered water fountains very effectively.Following are some of the major utilities of using solar water fountains.
Eco-friendliness of Solar Fountains
Luxury items generally means consumption of more power. Running high-end water fountains mean using constant power supply.Constant power supply increases demand of substances like coal, which has serious impacts on environment. Thus, polluting power toll is rising constantly and we need to do something to save power.
Contribute towards environment by saving power. Use solar water fountains that run on solar energy and get equal benefits. Small steps make a big difference. With the elegance of solar fountains you are saving several watts of power.
Power consumption
Power consumption is heavy during the spring and summer periods. Usage of electrical devices shoot up during these period. This results in serious impact on power supply and several areas even experience power cuts. We must also take initiative to save power and make a small but effective difference.
Such effective small step would be installing a solar water fountain. These solar fountains are equally beautiful and elegant like the other fountains but the main advantage is these fountains save power.
Useful Fountains
Maintenance and usage of these solar fountains are so simple. No extra weather proof cord is required neither there is any need for creating any link with any power point. Changing position of solar water fountain is comparatively much easier than the other variety of fountains. What you need to do is just drain the solar fountain and move the cords and solar panel in the right manner. You can enjoy the elegance of solar fountains by placing it anywhere where it can get sunlight. The size of these fountains is so portable that it can be moved easily according to the requirements.
Cost-Effectiveness Of These Fountains
Enjoy the elegance of solar fountains also because they are cost-effective. You can find many varieties of these fountains and the price factor is also varied. These fountains require solar panels which are not expensive at all.
Solar Fountains Are Not Rigid
Solar fountains are not necessarily need to be used for gardening. Though the solar water fountains are mainly outdoor fountains but there are indoor varieties also. Indoor solar fountains can wonderfully grace up your interiors but you must ensure that the area gets sufficient sunlight. Not just summers, when the fountains can easily generate charge. Solar water fountains are also effective during the winters. Thus, these solar fountains are very flexible and its elegance can be enjoyed even after summers.
Eco-friendliness of Solar Fountains
Luxury items generally means consumption of more power. Running high-end water fountains mean using constant power supply.Constant power supply increases demand of substances like coal, which has serious impacts on environment. Thus, polluting power toll is rising constantly and we need to do something to save power.
Contribute towards environment by saving power. Use solar water fountains that run on solar energy and get equal benefits. Small steps make a big difference. With the elegance of solar fountains you are saving several watts of power.
Power consumption
Power consumption is heavy during the spring and summer periods. Usage of electrical devices shoot up during these period. This results in serious impact on power supply and several areas even experience power cuts. We must also take initiative to save power and make a small but effective difference.
Such effective small step would be installing a solar water fountain. These solar fountains are equally beautiful and elegant like the other fountains but the main advantage is these fountains save power.
Useful Fountains
Maintenance and usage of these solar fountains are so simple. No extra weather proof cord is required neither there is any need for creating any link with any power point. Changing position of solar water fountain is comparatively much easier than the other variety of fountains. What you need to do is just drain the solar fountain and move the cords and solar panel in the right manner. You can enjoy the elegance of solar fountains by placing it anywhere where it can get sunlight. The size of these fountains is so portable that it can be moved easily according to the requirements.
Cost-Effectiveness Of These Fountains
Enjoy the elegance of solar fountains also because they are cost-effective. You can find many varieties of these fountains and the price factor is also varied. These fountains require solar panels which are not expensive at all.
Solar Fountains Are Not Rigid
Solar fountains are not necessarily need to be used for gardening. Though the solar water fountains are mainly outdoor fountains but there are indoor varieties also. Indoor solar fountains can wonderfully grace up your interiors but you must ensure that the area gets sufficient sunlight. Not just summers, when the fountains can easily generate charge. Solar water fountains are also effective during the winters. Thus, these solar fountains are very flexible and its elegance can be enjoyed even after summers.
Tuesday, June 9, 2009
How To Build a Solar Hot Water Heater To Save Over 30% of Electrical Bills
When you learn how to build a solar hot water heater, you are looking forward to saving over 30% of your electricity bills in your home.
The installation of a solar hot water heater not only saves energy or power bills, but also controls global warming. Homeowners may install solar heaters at their home. It has become a tough time for all these house owners who have been worried on the alarming rise of energy rates and the enormous demand for energy which the power companies are facing difficulty in meeting the expectations. Let us look into solutions that will save the planet, save our money and save our energy.
A different approach needs to be adapted for solving this problem. Looking at such situation lot of energy saving guides flooded the market with numerous ideas on how to save energy or build an energy generator at home. Solar hot water heaters simply absorb the energy from the sunlight that is free to use. This energy is converted to electrical energy that is used for the heating purposes. In earlier days the same concept of heating water was used but with a different approach. The water was getting the heat from the warmth of the sun.
Today with latest technologies and advanced inventions, there several economical way to generate the power to heat the solar hot water heaters installed at your home. The parts for the making of the heater can be easily found online and all the materials cost less than $100. It is considered a one time investment that will provide you a lifetime’s saving. The energy from the solar hot water heater is non pollutant as no gases are evolved. This makes it a system that goes green and controls the global warming.
The installation of a solar hot water heater not only saves energy or power bills, but also controls global warming. Homeowners may install solar heaters at their home. It has become a tough time for all these house owners who have been worried on the alarming rise of energy rates and the enormous demand for energy which the power companies are facing difficulty in meeting the expectations. Let us look into solutions that will save the planet, save our money and save our energy.
A different approach needs to be adapted for solving this problem. Looking at such situation lot of energy saving guides flooded the market with numerous ideas on how to save energy or build an energy generator at home. Solar hot water heaters simply absorb the energy from the sunlight that is free to use. This energy is converted to electrical energy that is used for the heating purposes. In earlier days the same concept of heating water was used but with a different approach. The water was getting the heat from the warmth of the sun.
Today with latest technologies and advanced inventions, there several economical way to generate the power to heat the solar hot water heaters installed at your home. The parts for the making of the heater can be easily found online and all the materials cost less than $100. It is considered a one time investment that will provide you a lifetime’s saving. The energy from the solar hot water heater is non pollutant as no gases are evolved. This makes it a system that goes green and controls the global warming.
Monday, June 1, 2009
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