Pay-back time

It is often used to judge small improvement projects on operating plant. Typically, a pay-back time of 2 to 5 years would be expected from such projects. 

Pay-back time as a criterion of investment performance does not, by definition, consider the performance of the project after the pay-back period. 

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Point D is known as the break-even point and the time to reach the break-even point is called the pay-back time. In a different context, the term break-even point is used for the percentage of plant capacity at which the income equals the cost for production. 

Pay-back time is the time required after the start of the project to pay off the initial investment from income point D on Figure 6.7. Pay-back time is a useful criterion for judging projects that have a short life, or when the capital is only available for a short time. 

Pay-back time — years Shows how soon investment will be recovered No information on later years... 

Pay-back time (as the annual savings are constant, the pay-back time will be the reciprocal of the ROR)... 

Pay-back time is the period required to recover the money initially invested in the project. Thus, the pay-back time is represented by the period (1-6) in the cash-flow diagram (Figure 13.5). The pay-back time is not just the period required for profits to be first generated—sufficient profits then have to be made to cover the initial expenditures made. 

Compare estimates of pay-back time and return on capital invested as estimates of a product s profitability. 

The number of people allocated to each project, i.e. the proportion of the research budget, will depend largely on the size of the eventual economic return set against a desired pay back time. If getting there quickly is of overriding importance then more... 

Costs and energy pay-back times of present PV systems at an armual production rate of lOMW were calculated to be 55()/W ( 83/kWh) and 5.7 years for poly-Si and 79/W ( ll9/kWh) and 6.4 years for a-Si PV systems, respectively. These cases correspond to the present level of PV technology. 

PV high cost, and long energy pay back time (EPT). 

In addition to the cost effectiveness of silicon ribbons, energy payback time (i.e. the time needed to produce the amount of energy that was consumed during the manufacturing of a solar system) is drastically reduced. In a recent life-cycle analysis of crystalline silicon wafer based PV systems, it was demonstrated that the energy pay-back times can be reduced by half (based on cut multi-crystalline wafers), by the use of RGS ribbons for systems in central Europe [97]. 

With ceramic membranes (typical pore size 0.2 pm) this legal limit of 10 ppm is easily obtained [18]. Average membrane flux is 150 1/m h values are reported between 125 and 6001/m h [19]. The interval between cleanings or the maintenance interval can amount to 1000 h. By combination of the membrane unit with a static separator the concentration factor can be as high as 180, the oil content in the final concentrate can amount to over 90%. The pay-back time for such an installation would be less than two years at a cost of NLG 94/m effluent, and related to the present costs of treatment [18]. 

In a typical example [20] 6.4 m of 0.2 pm membranes are used in a pilot scale operation, yielding average fluxes between 100 and 1251/m h in a installation working at 55°C. The concentration factor for the membrane installation varies between 6 and 12. Due to the extreme fouling nature of the feed, periodic cleaning is compulsory, but can be restricted to once a week. The system has been in operation since August 1992. The pay-back time is less than 3 years. 

Microfiltration with HIC s 0.2 xm membranes yields average fluxes of 250 1/m h at temperatures from 40 to 70°C the pH lies between 9 cmd 11. The permeate contains less than 100 ppm oil. This treatment extends the life time of the degreasing bath up to five times pay back time is less than two years. Similar data are reported of Carbosep, Le Carbone Lorraine and Atech membranes [19,22,37,38]. 

If the fouling problem cannot be relieved by the use of additives it may be necessary to make modifications to the plant. Modification to allow on-line cleaning of a heat exchanger can represent a considerable capital investment. Before capital can be committed in this way, some assessment of the effectiveness of the modification must be made. In some examples of severe fouling problems the decision is straightforward, and a pay back time of less than a year could be anticipated. In other examples the decision is more complex and the financial risks involved in making the modification will have to be addressed. 

In mines production often takes place a round the clock and all the processes have been designed for highest availability. Each interruption means production loss. If visual inspection can be carried out during normal operation, the pay back time for the test device will be short. 

Goal Develop a new product idea with specific (sustainable) properties for a specific market (including envisioned investments and pay-back time). 

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