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86 dictate the correct blend requirements for ongoing deicing When applied to typical airport conditions, the model out- events. At sites with remote blending capabilities, vigilance put clearly shows the value of implementing the use of diluted is required in checking fluid concentrations to ensure that fluids in the deicing operation. In many cases, the financial required FFPs and associated holdover time guideline per- outlay to implement use of diluted fluids can be recouped in a formance are met. year or two. A sample of a completed model run using typical values for evaluating the introduction of diluted Type I fluid is provided. In the example, the model indicates that an initial Practice Limitations investment of just over $1 million can be recouped in the De/anti-icing fluid dilutions should be used in accordance course of one season, leading to operational savings of over with the general guidelines contained in Tables 48 and 49. The $1 million per season thereafter. operator must ensure that the requisite buffer requirement is adhered to for Type I fluids. In addition, for Type II, III, and Sample Completed Model IV fluids, the fluid concentration must be selected such that the LOUT and aerodynamic performance requirements (fluid The following figures provide an example of running the flow off criteria) are met. SAE AIR 5633 presents information model. on the aforementioned forced air systems. Figure 30--Instructions Page: The user is not required to enter any information on this page. The page does not change from user to user. Application of Findings to Create Figure 31--Assumptions Page: The user is not required to Cost-Benefit Model enter any information on this page, but may alter the default The cost-benefit model is a user-friendly tool that can be values used for the percentage of Type II/III/IV operations by used by operators to determine if making a switch from ready- fluid dilution and temperature if desired and/or the FFP buffer to-use Type I fluid or neat Type II/III/IV fluid to diluted fluids for Type I fluid. The user in this case has not altered the default is financially advantageous. The model will estimate the annual values. cost savings, annual glycol savings, and number of years until Figure 32--Background Page: The user has indicated on this the initial investment has been recouped. page that he is considering a switch to Type I fluid mixed to a The model was tested for different situations by inputting 10C buffer, but not a switch to diluted Type II/III/IV fluids. various parameter values representing typical and extreme The user has entered the number of annual operations with operations. The model was refined and validated by this Type I fluid at the required temperature ranges, the amount of process. The final version of the model may be downloaded at Type I fluid used per season (1,500,000 liters), the cost of the the link found at http://apps.trb.org/cmsfeed/TRBNetProject- current Type I fluid ($2.00/liter), and the percentage of glycol Display.asp?ProjectID=122. in the current Type I fluid (55%). INSTRUCTIONS Welcome to the fluid dilutions cost-benefit model. This model will calculate the estimated annual glycol savings and cost savings that can be achieved by switching from a Type II/III/IV neat fluid only operation to a fluid dilutions operation and/or by switching from a Type I ready-to-use fluid operation to a Type I 10 buffer fluid operation. The model will also calculate the number of years it will take to breakeven from the initial investment required to implement diluted fluid operations. Instructions: Fill in all cells that are shaded blue, except those where "not applicable" is indicated. When you have filled in all cells on a page, follow the instructions that appear in red at the bottom of the page. Further comments/instructions are provided in some cells. These comments/instructions are indicated by red triangles that appear in the upper right corner of the cell and can be seen by hovering over the cell. Disclaimer: This model has been prepared by APS Aviation Inc. for the Transportation Research Board. The model makes several assumptions that may not be accurate in every business and/or operational environment. The user is recommended to review the assumptions listed on the next page and consider conducting further analysis if required. To begin, go to the next page (Assumptions) Figure 30. Sample instructions page.