Life-cycle cost analysis (LCCA) is a method for assessing the total cost of facility ownership. It takes into account all costs of acquiring, owning, and disposing of a project. LCCA is especially useful when project alternatives that fulfill the same performance requirements, but differ with respect to initial costs and operating costs, have to be compared in order to select the one that maximizes net savings.

For example, LCCA will help determine whether the incorporation of a good HVAC or glazing system, which may increase initial cost but result in dramatically reduced operating and maintenance costs, is cost-effective or not.

LCCA is not useful for budget allocation.

Lowest life-cycle cost (LCC) is the most straightforward and easy-to-interpret measure of economic evaluation. Some other commonly used measures are Net Savings (or Net Benefits), Savings-to-Investment Ratio (or Savings Benefit-to-Cost Ratio), Internal Rate of Return, and Payback Period. They are consistent with the Lowest LCC measure of evaluation if they use the same parameters and length of study period. The approach to making cost-effective choices for projects can be quite similar.

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Here is my experience based on energy audits of pumping systems in various chemical, metal, textile & petrochemical units. Design systems with lower capacity and total head. Do not assume these requirements are fixed. Calculate flow requirement based on actual mathematical nos without margins in each stage & then add 10-20% straightforward as Normal capacity of the pump. For example if process side heat load in an exchanger is based on normal flow of say 100 M3/hr then do not consider cooling water requirement for peak condition of 120 or say 140 M3/hr. Just calculate it based on normal flow of 100 M3/hr at this stage. Total head requirements can be reduced by: lowering process static gage, pressure, minimizing elevation rise from suction tank to discharge tank, reducing static elevation change by use of siphons, lowering spray nozzle velocities, lowering friction losses through use of larger pipes and low-loss fittings, and eliminating throttle valves.

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System Background In the concentrator section of phosphoric acid plant, weak phosphoric acid is concentrated by evaporation in graphite made evaporator. This is normally operated under vacuum & ~88°C temperature due to highly corrosive nature of phosphoric acid (PA). Over a period of time, the tubes of this exchanger require cleaning for removal of deposits & fouling material. This is a normal practice in both plants i.e. PAP-I & PAP-II.

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ASDs are ideally suited for variable-torque loads from centrifugal pumps, fans, and blowers when the system load requirements (head, flow, or both) vary with time. Conditions that tend to make ASDs cost-effective include the following: High horsepower (greater than 15 to 30 hp)—the higher the pump horsepower, the more cost-effective the ASD application. Load type—Centrifugal loads with variable-torque requirements (such as centrifugal pumps or fans) have the greatest potential for energy savings. ASDs can be cost-effective on positive displacement pumps, but the savings will generally not be as great as with centrifugal loads.

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Researchers are studying the viability of creating electricity from microbes that are continuously fed with wastewater. If this technology reaches a proven and commercially realizable point, we could see a new edge technology in power generation.

Researchers from the University of Washington in St. Louis have been working on microbial fuel cell that generates electricity from wastewater. The science behind this technology is quite simple. Wastewater contains, among other things, organic matter. This organic matter can serve as a feedstock for many bacterial reactions.

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• Can be made from natural sugar or starch including waste materials.
• Costs less than ethanol.
• Has 92% of the energy content of gasoline.
• Mixes well with gasoline or ethanol.
• Evaporates more slowly than either gasoline or ethanol.
• Can be used in place of gasoline with no engine or fuel system changes.
• Makes usable hydrogen as a by product.
• Higher energy content (110,000 Btu’s per gallon for butanol vs. 84,000 Btu per gallon for ethanol). Gasoline contains about 115,000 Btu’s per gallon.

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Reduce Losses from Storage Tanks

Chemical engineers Richard D. Offeman and George H. Robertson at the ARS Western Regional Research Center in Albany, Calif., think it may be possible to cut energy costs by using a series of specially designed permeable plastic sheets, or membranes, to produce ethanol from fermented broths of corn, or straw and other kinds of biomass feedstocks.

The technology will help to address the serious concern regarding the energy efficiency of bioethanol production, according to Robert L. Fireovid, ARS national program leader for process engineering and chemistry, Beltsville, Md.

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This is in continuation of my previous article on 'Thermodynamics of Thermal Cycles' & is related to practical aspects of it.

All standard heat engines (steam, gasoline, diesel) work by supplying heat to a gas, the gas then expands in a cylinder and pushes a piston to do its work. The catch is that the heat and/or the gas must somehow then be dumped out of the cylinder to get ready for the next cycle.

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In the literature surface tensions of liquids are usually given at one temperature only (often 15 or 20 °C). As the temperature is raised, the surface tension decreases and becomes zero at the critical point. Based on this observation the surface tension at temperature T2 can be estimated for most liquids from the following simple equation if surface tension at another temperature T1 and critical temperature Tc of the liquid are known

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Perfect tips for the Summer!



Cooling costs can chill your budget in the peak summer months। Here are few tips for chilling out without going broke:

• Block out the sun. Using shades and blinds to block sunlight minimizes the amount of energy needed to cool your house. It's also worth noting that dark-colored exterior walls and roof tops can absorb up to 90% of the sun's radiant energy. To keep things cool, try painting your house a brighter color.

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According to Philips Lighting a standard incandescent light bulb costs around €1, and uses €15-worth of electricity a year. A low-energy one costs €5-6 and uses €3-worth. The payback on investing in a compact fluorescent bulb, therefore, is less than a year. Yet low-energy lighting makes up only 30% of Philips's sales.

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• For ideal mixtures, relative volatility can be taken as the ratio of pure component vapor pressures.
• Tower operating pressure is most often determined by the cooling medium in condenser or the maximum allowable re-boiler temperature to avoid degradation of the process fluid.
• For sequencing columns:

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Some Facts
For those who are willing to take a look, and utilize golden opportunity for saving,

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1. Packed towers almost always have lower pressure drop than comparable tray towers.
2. Packing is often retrofitted into existing tray towers, to increase capacity or separation. Thus same size of packed towers can handle more than tray towers.
3. For gas flow rates of 500 ft3/min (14 m3/min) use 1 in (2.5 cm) packing, for gas flows of 2000 ft3/min (57 m3/min) or more, use 2 in (5 cm) packing.

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1. In many cases you can use lower wattage bulbs and get same amount of light. Look for lumens on the bulb (CFL) & not for watts. Lumen indicates the brightness while power indicates eenrgy required to illuminate the area.
2. Always plan bulb location in such a way that the light is not hindered by any other room fixture.
3. White light is more comfortable than any other light for reading & day to day use. So should consider it in studies, drawing room etc. Other types can be considered for infrequently used areas e.g. toilet, bathroom etc.

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1. Select proper size AC based on room size, family members, wall & window area etc.
2. Keep your refrigerator & freezers filled to capacity without restricting air circulation.
3. Regularly clean the condenser parts of your refrigerator & AC both to have better efficiency without loosing energy.

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