Life cycle alternating

Life cycle cost analysis is the proper tool for evaluation of alternative systems (11,12). The total cost of a system, including energy cost, maintenance cost, interest, cash flow, equipment replacement and/or salvage value, taxes, inflation, and energy cost escalation, can be estimated over the useflE life of each alternative system. A Hst of life cycle cost items which may be considered for each system is presented in Tables 3 and 4. Reference 14 presents a cash flow analysis which also includes factors such as energy cost escalation. 

In considering the economics of process alternatives, it is important to think about the total life cycle costs. There is an increasing interest in this concept in the environmental area, with a recognition of the need to incorporate waste treatment, waste disposal, regulatory compliance, potential liability for environmental damage, and other long term environmental costs into project economic evaluation. Similarly, we must consider life cycle safety costs. Some examples of factors which should be considered include ... 

The life cycle cost of a process is the net total of all expenses incurred over the entire lifetime of a process. The choice of process chemistry can dramatically affect this life cycle cost. A quantitative life cycle cost cannot be estimated with sufficient accuracy to be of practical value. There is benefit, however, in making a qualitative estimate of the life cycle costs of competing chemistries. Implicit in any estimate of life cycle cost is the estimate of risk. One alternative may seem more attractive than another until the risks associated with product liability issues, environmental concerns, and process hazards are given due consideration. Value of life concepts and cost-benefit analyses (CCPS, 1995a, pp. 23-27 and Chapter 8) are useful in predicting and comparing the life cycle costs of alternatives. 

The Broad View and Life Cycle Cost of Alternatives... 

Tools to apply such a more broad view of a process would pay inherently safer dividends. One tool might include instructions on how to estimate the life cycle cost of proposed alternative solutions. Such a tool is not presently fully developed and available in the public domain. Training to assist in estimating life cycle cost is needed. 

The subject of the study can be either a single energy-using device, such as a pump, or an entire ventilation system with all its components. A study focuses on the life cycle of the system or device, and normally is a comparison of two or more alternatives. The goal is to find the most economical solution on the basis of the total costs (investment and operation). 

Capital investment decisions are best made within the context of a life-cycle cost analysis. Life-cycle cost analysis focuses on the costs incurred over the life of the investment, assuming only candidate investments are considered that meet minimally acceptable performance standards in terms of the non-inonetary impacts of the investment. Using life-cycle analysis, the capital investment decision takes into account not just the initial acquisition or purchase cost, but maintenance, energy use, the expected life of the investment, and the opportunity cost of capital. When revenue considerations are prominent, an alternative method of analysis such as net benefit or net present value may be preferred. 

Calculations of life-cycle costs, net benefits, or other measures of economic performance are commonly performed on electronic calculators, commercial spreadsheet software, or by hand. The calculation approach for life-cycle costs is to first compute the net cost amount in each period for each alternative, C(t,x). The life-cycle cost (LCC) of each alternative is then calculated as the sum of the discounted values of C(t,x) over the entire planning horizon ... 

Capital investments can also be selected on the basis of other measures of performance such as return on investment, internal rate of return, and benefit-cost ratio (or savings-to-investment ratio). Flowever, care must be taken in the application of these methods, as an incremental analysis is required to ensure consistent comparison of mutually exclusive alternatives. Also, rather than requiring a separate value to be calculated for each alternative, as in the case of the life-cycle cost method, these other methods incorporate the difference between two mutually exclusive alternatives within a single measure. For example, the net benefits measure directly pressures the degree to which one alternative is more economically desirable than another. 

A first obvious consequence of such considerations is that we should not only look at the costs of the product from an economic point of view, but that we must consider the costs of the production process in a broader sense. We must take into account the raw materials used, the amount of energy invested and the possibility to design alternatives, more environmentally friendly processes. In other words, we should not only look at the desired product, but we must consider the total life cycle of the product The design of a production process taking into account these aspects is often referred to as integral life cycle management. 

Life cycle inventory of the alternative technological systems... 

Khoo, H.H. Tan, R.B.H. (2006) Life Cycle Evaluation of CO2 Recovery and Mineral Sequestration Alternatives. Environment Progress, 25(3), 208-217. 

Department of Environment, Transport and the Regions (UK), Life Cycle Assessment of Polyvinyl Chloride and Alternatives, DETR, London (2001). 

Reduced Life Cycle Impact of structures on the environment, especially by Choices of Materials (e.g., depending on local availability and forest management practices wood can be a versatile, sustainable alternative) and Construction Methods that Minimize the Production of GHGs —Construction Waste Management including Recycling and Reuse. 

The aim of the Life Cycle Impact Assessment (LCIA) is to facilitate the interpretation of the results of the inventory analysis. The result of the inventory analysis is an emission profile for each alternative system. In this study the emission profile is the total of all emissions to air, water and soil from the grave-to-cradle chain for the use of cushion vinyl floor covering, including the up chain processes, like electricity production and the down chain processes, like the incineration and landfill of the waste. Such an emission profile may consist of hundreds of emissions and extractions. In LCA impact assessment the total of interventions (emissions, extractions) of a process chain is evaluated in terms of environmental problems (impact categories). 

Strongyloides ratti has two developmental routes in its life cycle (Fig. 5.1) and this developmental choice shows phenotypic diversity. The parasitic phase of S. ratti is a parthenogenetic female (Viney, 1994). Eggs that pass out of a host can complete the free-living phase of the life cycle by two alternative developmental routes, termed heterogonic and homogonic. In homogonic... 

Trichinellosis is caused by the parasitic nematode Trichinella spiralis. This parasite has a complex life cycle that alternates between intestinal and muscle cell compartments of the host. This nematode infection is unusual because 7. spiralis is an intracellular parasite of mammalian cells. In addition, the broad host range of this parasite includes most mammals. The disease in humans has intrigued parasitologists, other biologists and public health workers for over a century (Cambell, 1983). The attraction to trichinellosis pardy stems from the debilitating and sometimes fatal effects that characterize this disease. 

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