Costing equality method

Some other methods are discussed in (24, 52) e.g., the equality method would charge the shaft exergy and the low-pressure steam exergy equally for the cost of high-pressure steam and turbine capital c = c, When the equality method is used the... 

The cost partition methods adopted are, as in [4], the equality and electricity as by-product [5] ones, with the following considerations ... 

Equality method this method assumes that alt products have the same specific (exergy-based) costs, so the investment (including steam turbine s cost) is distributed equally into the products (steam and mechanical/electric energy). This method is applied here for the evaluation of the base case (actual plant situation). Because the plant chosen for this study nowadays sells some surplus to the grid and some bagasse to other plants, the revenues from these sales are included in the exergy-cost balance. 

Applying the equality method from Thermoeconomic Analysis to the equations (1) and (2), the actual specific (exergy-based) energy costs are evaluated for each of the above mentioned base cases I and II. 

An important factor to be considered is the computational cost. Continuum methods are noticeably less expensive than simulation methods based on discrete models. On the other hand, simple properties, as the solvation energy AGso of small and medium-size solutes are computed equally well with both continuum and discrete methods, reaching chemical accuracy (Orozco et al., 1992 Tomasi, 1994 Cramer and Truhlar, 1995a). There is large numerical evidence ensuring that the same conclusion holds for other continuum and discrete methods as well. The evaluation of A(jso at TS has given almost identical results in several cases, but here numerical evidence is not sufficient to draw definitive conclusions. 

The products of each system were costed using two different techniques the equality method and the by-product work method (1, 2 ). Every case analyzed accounts for maintenance as well as fuel expenses but excludes other operating costs. Capital investment is amortized at an after-tax discount rate of 8.5%. The effects of income taxes, ad valorem taxes, and depreciation (see (3) for the formulation of the annualization factor accounting for capital, taxes and depreciation) are included, while the effects of inflation were neglected. 

Figure 1. Skeleton schematic of 1960 system available-energy flows (megawatts). Also shown are the unit costs of the steam and electricity outputs based on the equality method and sunk capital costs.

Note, too, that while the company s decision to co-generate power (along with the steam that it needed to produce) might have been based on a by-product work analysis once engaged in the production of electricity and its sale to outside consumers, the company should (and would prefer to) use the equality method (or, better, the extraction method) for costing power—at least the power to be sold. 

During the 1960 s, reverse osmosis was compared with other methods of demineralization. It was indicated in these comparisons that reverse osmosis could not compete favorably with ion exchange at dissolved solids concentrations below 700 mg/fi and that its most favorable area of use would be from about 1,200 to 5,000 mg/6 dissolved solids. This idea has been totally refuted because some of the most successful applications of reverse osmosis, particularly as part of the process to produce high purity water, have been in treating low dissolved solids water. Water containing 200 mg/ dissolved solids or less has been treated at costs equal to or lower than those of ion exchange alone. 

The suggested method is appropriately implemented at the practice. The cost and working hours of unit measurement of it is less than of any alternative method of destructive test and with respect to the authenticity inspection of Stress-Deformation the given method is inferior only to destructive testing. The method was successfully implemented while evaluation of service life of main pipe-lines sections and pressure vessels as well. Data of method and instrument are used as official data equally with ultrasonic, radiation, magnetic particles methods, adding them by the previously non available information about " fatigue " metalwork structure. 

A fourth method of computing depreciation (now seldom used) is the sinking-fund method. In this method, the annual depreciation A is the same for each year of the life of the equipment or plant. The series of equal amounts of depreciation Aq, invested at a fractional interest rate i and made at the end of each year over the life of the equipment or plant of s years, is used to build up a future sum of money equal to (Cpc S). This last is the fixed-capital cost of the equipment or plant minus its salvage or scrap value and is the total amount of depreciation during its useful life. The equation relating i Fc S) and Ao is simply the annual cost or payment equation, written either as... 

For prehminary screening and easibility studies or for rough cost estimates, one may wish to employ a version of the isothermal method which assumes that the liquid temperatures in the tower are everywhere equal to the inlet-liquid temperature. In their analysis of packed-tower designs, von Stockar and Wilke [Ind. Eng. Chem. Fun-dam. 16, 89 (1977)] showed that the isothermal method tended to underestimate the reqmred depth of packing by a factor of as much as 1.5 to 2. Thus, for rough estimates one may wish to employ the assumption that the temperature is equal to the inlet-liquid temperature and then apply a design fac tor to the result. 

The annualized capital cost (ACC) is the product of the CRF and TCC and represents the total instaUed equipment cost distributed over the lifetime of the project. The ACC reflects the cost associated with the initial capital outlay over the depreciable life of the system. Although investment and operating costs can be accounted for in other ways such as present-worth analysis, the capital recovery method is preferred because of its simplicity and versatUity. This is especiaUy true when comparing somewhat similar systems having different depreciable lives. In such decisions, there are usuaUy other considerations besides economic, but if all other factors are equal, the alternative with the lowest total annualized cost should be the most viable. 

Using a differential cost function such as that of Fiber and Karplus, the potential energy is averaged over the path by including a factor of 1/L. In other definitions, such as the one employed in the MaxFlux method, there is no such nonnalization. Therefore, if the potential is set to zero, the MaxFlux method will find that the best path is the straight line path connecting reactants and products. However, methods where the differential cost is proportional to 1 /L will find that all paths are equally good. 

---