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Showing posts with label DC scroll compressor. Show all posts
Showing posts with label DC scroll compressor. Show all posts

Thursday, February 16, 2012

Air-conditioning with direct solar

Air-conditioning is considered as a luxury, even in tropical countries where the day temperatures are well above 35C, and humidity high. The increasing electricity cost makes air-condisononing unaffordable to many people, though it is necessary for simple comfort. One of the main reasons why the cost of power is high and still keeps rising is, the way the power is generated and distributed. • The primary cost is the fuel cost and its ever increasing trend • The inefficiency of power generation and distribution • All house hold appliances are made to be compatible with AC power distribution. • Even solar generated power (DC direct current) is converted into AC (alternate current), in order to be compatible with AC grid. The above issues can be easily addressed by following the simple method, outlined below, so that air-conditioning becomes affordable to everyone. We are discussing about various renewable energy source options, particularly about solar energy for air-conditioning in this article. The centralized power plants operate in remote locations with an easy access to fuel source. They generate power from coal, oil or gas and then transmit power through a common grid to various consumers. During this transmission, there is a grid loss up to 10%.First it reaches a sub-station, where the high voltage power such as 11Kv/22kv/33Kv is stepped down to 220V/440V as the case, may be. During this process, there is a loss of power up to 5%. When this low voltage power reaches your home, you have to convert them into DC supply, using AC/ DC converter. For example, you need to use your laptop or PC, you need a converter. During this process, there is again a loss of power up to 5%. The efficiency of power generation by fossil fuels is only about 35%, and the balance 65% is emitted as waste heat in the form of greenhouse gases. The net power efficiency at the point of usage at our home will be only about 25-27%. Only 27% of the heat value of the fuel is converted and supplied, reaches you in the form of electricity. The rising cost of fuel and inefficiencies in generation and distribution, are the major factors for such high cost of power. Imagine, how many decades we have been using this power using the same technology, and paying our bills! One can easily justify why we should switch over to renewable energy source. It makes a great sense of economics and environmental protection! Since we have been using such power distribution systems for so many decades, all the house appliances are manufactured to be compatible, to the power supply. Unfounately, many of our electronic appliances can operate only on DC current. This has forced us to use many converters at our homes, of various specifications, for various uses. That is exactly why we are using a rectifier to convert the solar power, which is a DC current, into Ac current, so that we can use air-conditioners readily available at stores, which are AC power compatible. But this conversion results in power loss of at least 5%. It will be easier and economical to use directly, solar DC power into DC powered Air conditioners. The solar panel should be connected directly to a split air conditioning unit, through a charge controller and battery bank. The power supply to the unit will be 48VDC, connected to the outdoor unit. The compressor used in this air conditioner is DC operated, scroll compressor, which is more efficient and operates smoothly, and it can be connected directly to your solar panel, without using a rectifier. You can also use a small wind turbine to connect to this air-conditioning system. You can even use this system in your caravan, when you are not driving! As a matter of fact, all your house appliances from TV to Vacuum cleaners can be directly connected to your solar panel without any rectifiers.

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.

Friday, February 10, 2012

Power your home with sun and water

Is it really possible, to power your home, with just sun and water? It sounds very simple and a perfect solution, for our energy hungry world. It is true, and it is possible, to generate your own electricity, for all your home needs, without depending upon the grid power. Even when, there is no sun for a week! Let us see how, this is possible. Photovoltaic (PV) solar, is getting popular, and many Governments in developed countries, subsidies the cost of solar panels, and also buy surplus power, at a higher tariff, than the grid power tariff.Goverments are doing this, to encourage more and more people, to opt for solar energy, a cleaner form of energy. Currently, solar panels are set up on roof tops, and the solar energy is used to power your appliances, and the surplus power, exported to the grid. At times of shortage, the power from the grid is drawn, to meet your home requirements. When you import power from the grid, the energy meter revolves in clock wise direction. When you export power to the grid, the energy meter, runs in anti-clockwise direction, indicating the export of surplus power to the grid. At the end of the month, you calculate the net power exported or imported, and accordingly collect the revenue from the Government based on fixed tariff, or pay to the Government based on their bill. But there is a catch! Power distribution companies distribute power, to consumers, at variable tariff, such as peak power and off peak power. The tariffs are high, during peak periods, and lower at off-peak periods. Solar system generates more power when the sun is bright, and generates less power during cloudy times. One should be able to generate solar power when the sun is bright, use it during the peak period. But grid tariff is at peak normally during the daytime, between 9 and 5. And lower at night time, between 6pm to 6am. Therefore, one should be able to generate power during bright sun shine, and use it during peak period. That means you should be able to generate your required power during the daytime, and use them in the night, because you don’t use much power, during daytime. How to overcome this anomalous situation, and still to meet your hundred percent power requirement at home? We can offer you a system that will generate power, while the sun shines. This power will generate Hydrogen gas, from pure water, and store it under pressure. Stored Hydrogen is your stored energy. It is like your overhead water tank. You can pump water and store it in the overhead tank, and use it, whenever you need it. But, your solar generated electricity cannot be stored in this way. You can store it, in a battery bank. But, these lead acid batteries are heavy, it requires regular maintenance, you cannot draw stored power from the battery more than 80% of its stored capacity, and finally, batteries have certain life span, usually 3-5 years, when it has to be substituted, with new batteries. If you calculate, the economics of solar system for its whole life cycle of say 10-15 years, including all battery replacements and maintenance cost, the initial investment will be high. In spite of all these expenses, one cannot guarantee with uninterrupted supply of power, to your home. But, you can store Hydrogen gas, any quantity, without any loss. You can generate your own electricity, using this stored Hydrogen, as and when, you require. You can still export your surplus power to the grid, and also meet all your power needs, even during peak periods! The overall cost of the system is higher, than solar grid connects system but it will offer you, an uninterrupted power, throughout the year. You will be eligible for carbon credit, and your system will earn you money, as you relax at home, with no worries about mounting power bills! The cost of energy keeps rising, as the oil prices go up. You may even be able to generate and store more Hydrogen, to fuel you car, like Honda FCX.Hydrogen solution is the solution of the future. We can design, engineer and install a system to meet your specific needs. Of course, we need to study your specific requirement, and suitability of your location.