Economic evaluation payback time

Economic evaluation of solar dryers usually aims at determining the payback time. The dynamic method of calculations takes the influence of inflation into consideration. The following considerations summarize this method, according to Boer [30]. 

In this research, the Desalination Economic Evaluation Program (DEEP) as spreadsheet tool originally developed for the IAEA by General Atomics has been applied to compare the results. Cost flow rates of product, net power product and simple payback period time in each scenario are determined in Table 6. 

Economics of residential fuel cells is more complex. Here the purchase price must be justified with sufficient savings in expenditures for energy over the lifetime of the power system. One method that may be used to evaluate feasibility of residential fuel cell power systems is a simple payback time. This is simply a ratio between purchase price and annual savings in electricity expenditures. The result suggests to the potential user... 

Cadmium cyanide. In January, 1989, API Industries in Chicago, installed a 5 gpm ARO system to evaluate cadmium cyanide recovery. Complete results are not available at this time. Laboratory tests and economic projections indicate that the rinses and bath are reclaimable and payback from ARO should be one year or less. 

Investment decisions are often based upon several criteria, such as annual return on investment (ROI), payback period (PBP), net present value (NPV), the average rate of return (ARR), present value ratio (PVR), or the internal rate of return (IRR). Discounted cash flow rate on return (DCFRR) is another popular means of evaluating the economic viability of a proposed project. Horwitz [1] recommended the DCFRR as the best means to determine the return on investment, because it accounts for the time value of money. The internal rate of return as an investment criterion gives the possibility that given cash flows may result in more than one internal rate of return. Cannaday et al. [2] developed a method for determining the relevance of an internal rate of return. They inferred that an internal rate of return is relevant, if its derivative with respect to each of the cash flows is positive. 

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