Insulation energy savings

Instrumentation malfunctions (distillation tower), 372-373 plugged orifice taps, 372-373 Insulated float chamber, 270 Insulation (energy savings), 218-219 Integral trusses (support lips), 84 Interface level, 303 Internal reflux, 13 Ionic hydrogen, 105 Iron oxide scale, 79 Iron sulfide, 372... 

In specifying the insulation thickness for a cylindrical vessel or pipe, it is necessary to consider both the costs of the insulation and the value of the energy saved by adding the insulation. In this example we determine the optimum thickness of insulation for a large pipe that contains a hot liquid. The insulation is added to reduce heat losses from the pipe. Next we develop an analytical expression for insulation thickness based on a mathematical model. 

Solution If operating costs are to be stated in terms of dollars per year, then the capital costs must be stated in the same units. Because the funds required for the insulation are to be paid back in equal installments over a period of 5 years, the payment per year is r(C0 + Cxx)A. The energy savings due to insulation can be calculated from the difference between Q(x = 0) = Q0, and Q ... 

Cost of insulation Values of energy saved Hours of operation Interest rate... 

Drying response data were obtained for each system over a range of operating temperatures to estimate energy savings. At equal levels of drying, the Insulated system operated at lower... 

The total-cost method does not in general provide a satisfactory means for making most insulation investment decisions, since an economic return on investment is required by investors and the method does not properly consider this factor. Return on investment is considered by Rubin ( Piping Insulation—Economics and Profits, in Practical Considerations in Piping Analysis, ASME Symposium, vol. 69,1982, pp. 27-A6). The incremental method used in this reference requires that each incremental in of insulation provide the predetermined return on investment. The minimum thickness of installed insulation is used as a base for calculations. The incremental installed capital cost for each additional V2 in of insulation is determined. The energy saved for each increment is then determined. The value of this energy varies directly with the temperature level [e.g., steam at 538°C (1000°E) has a greater value than condensate at 100°C (212°F)]. The final increment selected for use is required either to provide a satisfactory return on investment or to have a suitable payback period. 

Thermal insulation in the form of mud, clay, straw, rags, and wood strips was first Used in tlie eighteenth century on steam engines to keep workmen from being burned by hot surfaces. As a result, boiler room temperatures dropped and it was noticed that fuel consumption was also reduced. The realization of improved engine efficiency and energy savings prompted the... 

Anonymous, "News in Brief. Energy-Saving Pipe Insulation," Du Pont Magazine, 77 (1) 28 (January/February 1983). 

Sprayed-on rigid urethane foam can provide more than energy savings to hot oil tanks. The cost of steam can more than justify this type of insulation, but the added benefits are better temperature control of the oil which improves its handling and... 

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