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Showing posts with label Solar panels. Show all posts
Showing posts with label Solar panels. Show all posts

Friday, February 17, 2012

The brick and morter of solar panels

Solar industry is growing at an accelerated rate as the world is facing an uncertain oil future and nuclear disaster. The cost of solar panels is steadily decreasing, but still it is beyond the reach of millions of people. Why the cost is so high and what can be done about it? In fact, the basic raw material for solar panel is nothing, but beach sand in the form of silicon dioxide. But the cost of sand increases from next to nothing to $ 1300 per kg, as it transforms into electronic grade polysilicon wafer. There are number of steps involved to convert raw sand into electronic grade silicon ingot that includes energy intensive processes and high technology inputs. The raw sand is often contaminated with various impurities, thus displaying different colours.The best quality sand with least impurities are further melted in arc furnace at 2000 C to get 95-98% pure silicon, called metallurgical grade silicon, with an estimated cost at $2 per kg.The metallurgical sand is further treated with Hydrochloric acid in a fluidized bed reactor and distilled to get Trichlorosilane. High purity silicon is made from Trichlorosilane (TCS) by chemical vapor deposition (CVD). The trichlorosilane is reduced with hydrogen gas forming pure grade Silicone crystal. The process involves high temperature reaction and toxic doping gases. The resulting electronic grade polysilicon costs almost $80 per kg at this stage. This is grown into single silicon crystal and drawn into an ingot. The highly pure silicon crystal ingot costs about$ 400 per kg .The silicon ingot is sliced into thin wafer using diamond saw. This process of wafering and polishing is expensive and the resulting silicon wafer costs as much as $1300 per kg.The thinly cut silicon wafer is doped with Phosphorus, coated on the heated surface of the wafer so that it diffuses into wafer uniformly. The doped wafer can generate electricity on exposure to sunlight. These wafers are cut into various sizes, polished and arranged on a back panel to form a solar panel. Conductive copper strips are fixed on the surface of the cells facing the sunlight. Finally a layer of glass is glued on top of the solar cells as a protective layer. The completed crystalline solar panel is ready for installation. The cost of solar panel varies from $2.5 up to $ 7.00 per watt, depending upon the make and construction. Some companies are already selling solar panels at the rate of $1 per watt, making it affordable. As the technology improves, the cost of solar panels is likely to come down further, making it competitive with conventional power sources. The cost benefit analysis will certainly favor solar energy in the future, as we are counting the cost of the damages done, by unprecedented weather conditions in many parts of the world, attributed to global warming. The cost of solar power is estimated at $0.25 per kwhr without any Government subsidy, based on solar panel cost at $ 5.00per watt. But this cost may come down to $0.06 per kwhrs, as the cost of $1.00 per watt solar panel, is made available in the market. In fact many individuals claim to assemble solar panels on their own at a cost much cheaper than market prices. The solar power cost will be certainly comparable to conventional power sources in the future. Those who don’t join the race now will be left behind with costly power bills.

Wednesday, February 15, 2012

Beat the heat with Solar

Are you wondering how to beat the heat in this summer, especially with power outage and blackouts, when everybody turns on their airconditioners? The grid fails with overloading, when all the air conditioners are switched on simultaneously, in a city. The situation is worst, when the grid fails and nobody has got power. This can be detrimental for IT companies, call centers, hospitals, hotels, schools supermarkets, continuous process industries, and even homes. Why not use a hybrid chiller, that runs both with solar as well as with electricity or gas? It can also be used with diesel power generators with waste heat recovery system. It is economical, reliable and flexible, and it makes sense for business and industry. Air-conditioners are major power consumers in tropical countries, where power outages are common and frequent. It directly affects the production, sales and profitability of a business. Hybrid air- conditioners are not available off the shelves in stores, but should be specifically designed and installed to meet your specific requirements. It depends on the country, location, power situation, number of sunny days in a year and Government regulations. There are business and industries that will use a substantial power for their air-conditioners. It is absolutely essential to maintain a comfortable ambience for a good working environment and productivity. In order to reduce your energy bills, you can plan to install a hybrid chiller. At least part of the load can be shared by PV solar power and hot water that can be installed on your roof top. If you have a diesel or gas fired engine or standby power generator, the engine jacket and exhaust cooling water can be supplemented with hot water. Hybrid chiller uses both an absorption chiller as well as an electric chiller. It offers flexibility to optimize the utilization of your cooling plant. A combination of solar hot water, waste heat from engines and off-peak power tariffs are taken into account while designing the system in such a way, the customer get the best economic outcome. During peak hours when grid power is in great demand and costs more money, the system will use solar hot water and gas heated hot water to run the absorption chiller, while eclectic chiller will take advantage of off-peak electrical power with lowest tariff, during night times. Hybrid systems can be installed with least disruption to your existing activities so that there will be no production or man-hour loss. Hybrid chiller is ideal for business and industries located in countries where government assistance is available, for renewable energy projects, by way of subsidies, cabon credit or other incentives. We will be presenting a case study in my future articles for small hybrid chiller installations. Companies interested in exploring this opportunity may contact us by sending an email, with all relevant informations, so that we can suggest you a proposal with costing and feasibility study. I encourage business and industries whose energy monthly bills are high with substantial portion towards air-conditioning, to contact us by email at this website. You will also be eligible for carbon credit to the extend you save your greenhouse gas emission!

Tuesday, February 14, 2012

Solar Air-conditioning

‘Clean Energy and Water Technologies’ (CEWT), will be presenting a series of articles, on how to generate and use various renewable energy sources and use them for our day today applications. These articles will be useful for individual families, businesses and small industries, to effectively use such energy sources. Many nations around the world, have now started realizing the importance of renewable energy; especially after witnessing fluctuating oil prices (oil price hike is caused due to many factors, most of them are beyond our control), the nuclear disaster at Fukashima Nuclear power plant in Japan, global warming and its natural consequences (unusual snow during summer and bush fires in winter etc.), we are now witnessing all over the world. In most of these cases, power failures are due to grid failures. In many countries, Government offer higher tariff for renewable energy, subsidies for cost of renewable energy equipments etc., to encourage people to opt for such energy sources. The most important incentive offered by renewable energy is, ‘a sense of independence’ to the consumer, not to depend on grid power, but to generate their own power, to meet their day to day requirements. Renewable energy is still expensive, but improving technological developments will change this situation. That is why; many industrialized countries in Europe, US and Japan, are now investing heavily in renewable energy industries. In this article we will discuss about ‘Solar air-conditioning’: Solar air-conditioning is a method of cooling space, in buildings, using (PV) photo voltaic solar panels, concentrated PV solar panels, and solar thermal heaters. 1. This can be achieved by generating electricity, using roof top solar panels similar to a system we normally use for lighting, to run a conventional type electrical air-conditioning unit. Individual houses and buildings have to be carefully studied, and systems have to be specifically designed, to get the optimum results. 2. Alternatively, we can use roof top solar water heaters to generate hot water. This hot water can be circulated through an absorption chiller, to generate chilled water. The chilled water will then be circulated through fan coils, mounted on the ceiling of the room, to be cooled. It is a close circuit unit, in which, the fan in the fan coil unit blows air across the fan coil, through which chilled water is circulated at 4.5℃ and returned back to the chiller at 8.5℃. The returning chilled water at 8.5℃ will be chilled again to 4.5℃ in the chiller and returned back to the fan coil unit. This process continues, as long as, we need to keep the room cool, at around 18-20℃. This article will not describe the principles, and methods of absorption chilling, which is a well established industrial practice. The hot water from the solar water heater can additionally be supplemented, from any other waste heat source. For example, if a business or an industry has a diesel operated engine or a generator, with water cooling, and then such water can be supplemented with solar heated water, to supplement the capacity of the airconditioner. Most of the diesel engines operate at an efficiency of around 30-40%, and the balance 60-70% is wasted as waste heat, into atmosphere, as greenhouse emission. Some diesel generators will have a radiator with coolant, or cooling water circulated through a cooling tower, for recirculation. The diesel engine cooling system can be suitable altered, to generate hot water to supplement the solar hot water. In many tropical countries in Asia, power failures or blackouts are common, and many businesses, industries, and beach resorts, have standby diesel generators as a backup power source. These customers can opt for solar air-conditioning that will offer them good savings. A typical 100TR solar air-conditioning unit in a beach resort, using back up diesel power generator cooling water, will be able to recover their investment in less than 5 years. It is economical, because the cost of power using diesel generators is high. In places, where piped natural gas is available, the system can be designed for both heating (during winter) and cooling (during summer), as well as, for back up hot water. The engine will be gas fired, and the waste heat can be used to supplement solar hot water. Alternatively, when the engine is not used, the gas can be used to generate hot water to supplement the solar hot water. The system can be designed in many ways to suit the conditions of the site and the customer’s requirement. In all our applications, we will try to substitute fossil fuel, with 100% renewable energy source, or at least, to supplement the fossil fuel, with renewable energy source, similar to a ‘hybrid car’. Solar energy can also be used to refrigerate critical, life saving medical vials and injectibles, in remote places where there is no grid power.