Bir üretim girdisi olarak enerji ve kontrolu

Abstract

u çalışmada sanayide bir üretim girdisi olan enerjinin verimli kullanılması genel olarak ve sektörel bazda incelenmiştir. Enerji tasarrufu konusunda yapılan çalışmalar hem ekonomik hem teknik yönden değerlendirilmiştir. Gelişen bir ülke olan Türkiye'nin enerji durumu, enerji tasarrufu konusunda yapılan çalışmalar ve yapılması gerekenler irdelenmiştir. Sanayi, konut, ulaştırma sektörleri ayrı ayrı incelenerek enerji tasarrufu konusunda alınacak önlemlerle ülke ekonomisine küçümsenemeyecek boyutlarda katkının sözkonusu olacağı görülmüştür. Ancak Türkiye'de enerji verimliliği konusunda gerekli çalışmalar ve uygulamalar yeterince yapılma makta, gerekli önlemlerin alınılmasında gecikilmektedir. Enerji ihtiyacımızın büyük bir bölümünü ithal ettiğimizi düşünürsek, ülke ekonomisinin rahatlaması, halkın refahı açısından, enerji verimliliği konusunda ne kadar hassas olmamız gerektiği ortaya çıkmaktadır. Özellikle, sanayileşmekte olan bir ülke olmamız nedeniyle, toplam enerji tüketimindeki payı giderek artan sanayi sektöründe mevcut tasarruf potansiyelinin diğer sektörlere göre daha kısa zamanda realize edilmesi mümkün görülmektedir.

Energy conservation does not mean having to do without energy. It should not be associated with rationing or curtail ment of energy sup-oly services. Rather, energy conservation means identifying areas of wasteful use of energy and taking action to reduce the waste to a bare rainumura or to eliminate the waste completely. In this way, the energy consummer can provide the same level of goods or services with less energy, or an expanded level of goods or services with the same amount of energy. Production costs in a factory are made up of : raw materials costs; labor costs; operating costs (spares, supplies, chemicals); and energy costs. Usually energy is simply lumped in to the total operating costs, and not considired as a seperate item. Depending on the industry, the processes emplayed, and the raw materials used and final product manufactured, energy costs can be as high as 70 percent of total production costs (e.g. : cement sector % 50, steel sector % 30, paper sector % 25, food sector % 7). It is possible to implement many energy conservation strategies at little or no cost to the energy consumer. On the other hand, some strategies may require large araaunts of copital to implement. It should be. understood that investments in energy conservation sheuld be evaluated on the same basis as any other invesment for having energy. Energy conservation has substantial benefits, both for industrial facilities and for the national economy. Among these can be listed the following:. Short lead times - most energy conservation pro-iects can be implemented in one year or less, thus offering much more immediate benefits than large, capital cost solutions such as new power plants which may take 5 to 15 years to bring on line.. Greater profitability/productivity - reduced energy consumption leads to savings in costs and improved profitability. Overall gains in r-roductivity may also be achieved throtigh energy conservation measures, particularly when production is constrained by energy availability.. Reduced load-shedding - energy conservation measures will reduce the rate of growth in overall demand, reducing the need for load-shedding in electricity and gas supply systems.. Reduced need for energy imports - the benefits of energy conservation vill be reflected in a reduced requirement for imported oil.. Improved foreing exchange position - a reduced demand for imported oil, a lower electricity demand, and lower gas demands will all help to lessen the foreign exchange resources needed for oil imports and for energy development projects.. Financially and economically attractive - a great majority of energy conservation projects have simple paybacks of less than 3 years, making them very attractive financially and economically. Over half of them have simple paybacks of less than 1 year. Furthermore, energy conservation often can "produce" energy at less than the cost of supplying an equaJL amount of energy (i.e., it is cheaper to save energy than to purchase it). Some of the main energy conservation opportunities which are applied in Turkey are: x Improving Boiler and Furnace Sfficiency Overall efficiency for boilers and furnaces is derived from two components: 1) Combustion efficiency, and 2) structural and other losses. Combustion efficiency is affected by the excess air and the exhaust temperature; it can be improved in the following ways: - excess air adjustment based on efficiency measurement (can improve efficiency a little, or significantly, depending on the condition of the existing burner; rapid payback if it works) - burner tip and deflector replacement ( may allow adjustment of excess air, as above, and can improve efficiency a little, or significantly, depending on the condition of the burner; rapid payback if it works) - new locally made burner (can improve efficiency to a large degree, presumming the burner is well made and can operate at low excess air; payback of approximately 1 year, but depends on existing efficiency) - new imported burner (can improve efficiency "i^ significantly at all loads; payback usually 2-3 years or more) - automatic combustion control (additional efficiency improvement with imported burner; recommended with imported burners only; payback of 4-5 years or more)... Structural and other losses include mainly radiation and convection losses from surfaces, from openings in a furnace, and from blowdown in a boiler. These higher than the liquid-to-liquid equipment, since larger surface areas are required to transfer heat. In boilers and furnaces, where high temperature differences are available, locally fabricated heat exchangers may be adequate. In most applications, however, low temperature differences require finned tube or even heat pipe heat exchangers, adding significantly to the cost. Coqeneration Cogeneration is an efficient technical solution to provide thermal and electrical energy simultaneously. It reduces (or eliminates) dependence on the utility grid; and it usually involves a large and expensive project. Cogeneration of useful heat ant electric power can be done in several common ways: 1) high pressure steam from a boiler turns a turbine generator, an low pressure steam exiting the turbine is used for process heat; 2) a gas turbine combustor is used to generate electricity, and the turbine exhaust passes through a waste heat boiler to generate steam for process heat; 3) diesel powered generators are used for electric power, the diesel exhaust and waste heat are recovered in the form of process hot water or low pressure steam. For cogeneration to be feasible, the facility must be a large consummer of both process heat and electric power: both gas turbine and boiler/ turbine generator systems begin to be attractive at 2 to 5 MW of electricity, while diesel engines are usually not attractive at much below 1 MW. Overall attractiveness of the project will depend on relative consumption of thermal and electric energy, and the relative cosis of the two. Maintenance requirements for the systems are high. The projects take a long time to reach the installation stage, and costs are usually high. Nevertheless, for large facilities such as paper mills, chemical industries, large textile and food processing plants, and some large buildings, cogeneration presents a very efficient and cost-effective alternative to purchased energy. -rill Buildings. Improve lighting efficiency. insulate building roofs. use exterior overhangs to shade walls and windows. use tight-sealing windows; ensure they are vrell sealed. use shades and curtains on interiors to minimize entry of solar radiation. Use ceiling fans in combinations with air conditioning eauipment, allowing a higher comfort temperature in the room. Transportation. vehicle tune-up and regular maintenance. daily checks to ensure maintenance of maximum tire pressures. reducing highway speeds to below 90 km/h. training of drivers to drive efficiently and safely. use of radial tires. use of air deflectors for trucks. monitoring and targeting vehicle fuel consumption. As a result, if energy conservation opportunities are are applied widely and actively, especially in industry, either companies and our country will get important benefits.