Chemical Engineering @ChemengFiles.Com

The photovoltaic industry is experiencing a period of strong growth despite the current economic crisis. The challenge for leaders in this industry is to continue to lower manufacturing costs as well as develop more efficient processes, in order to resist strong pressure on prices. As the industry becomes more global and innovative, new key players in the market, particularly cells that produce crystalline silicon (c-Si) and new more efficient thin film cells. This will allow manufacturers of photovoltaic cells to achieve comparable cost to potentially fossil energy sources.

Air Liquide strengthens its leading position in gas and services in the photovoltaic industry: more than half of the 10 major manufacturers of crystalline silicon solar cells, and over 40% of the factories of thin film solar cells the world are already customers of Air Liquide.

In the course of this work a curious anomaly was discovered in the behavior of emulsion polymerized compression molded dicumylperoxide cured SBR. This material showed lack of time shift invariance in the region of very small strains in which elastomers generally follow a linear stress-strain law. Normally, non-preservation of time shift Ultra-high-Q (UHQ) silica microspheres have found research applications in diverse fields ranging from telecommunications to nonlinear optics to biological and chemical sensing. However, despite having quality factors greater than 108, the silica microsphere has not moved to an industrial setting because of several major drawbacks. The most hindering is the manual fabrication technique used that makes tight process control difficult and integration with other optical or electrical components impossible. Despite the strong desire to fabricate an integrated UHQ microresonator on a planar substrate, the highest quality factor achieved for any micro-fabricated planar micro-cavity (at the time of my first publication) was over 4 orders of magnitude lower than for silica microspheres. In this thesis, a process for creating planar micro-cavities with Q factors in excess of 400 million on silicon wafers is demonstrated. The advantage of these planar ultra-high-Q (UHQ) microtoroid resonators is that they successfully overcome the previously mentioned drawbacks of silica microsphere resonators while maintaining nearly identical, if not better, performance characteristics. Additionally, due to the planar nature of these new devices, functionality has been integrated in-situ while maintaining UHQ for the first time, such as active resonant frequency tuning, coupling control, and low-threshold lasing.

Today’s process and heating applications continue to be powered by steam and hot water. The mainstay technology for generating heating or process energy is the packaged firetube boiler. The packaged firetube boiler has proven to be highly efficient and cost effective in generating energy for process and heating applications.

Conducting a thorough evaluation of boiler equipment requires review of boiler type, feature and benefit comparison, maintenance equirements and fuel usage requirements. Of these evaluation criteria, a key factor is fuel usage or boiler efficiency.

Boiler efficiency, in the simplest terms, represents the difference between the energy input and energy output. A typical boiler will consume many times the initial capital expense in fuel usage annually. Consequently, a difference of just a few percentage points in boiler efficiency between units can translate into substantial savings. The efficiency data used for comparison between boilers must be based on proven performance to produce an accurate comparison of fuel usage. However, over the years, efficiency has been represented in confusing terms or in ways where the efficiency value did not accurately represent proven fuel usage values. Sometimes the representation of “boiler efficiency” does not truly represent the comparison of energy input and energy output of the equipment.

This Efficiency Facts Booklet is designed to clearly define boiler efficiency. It will also give you the background in efficiency needed to ask the key questions when evaluating efficiency data, and provide you with the tools necessary to accurately compare fuel usage of boiler products, specifically firetube type boilers.

Remember, the initial cost of a boiler is the lowest portion of your boiler investment. Fuel costs and maintenance costs represent the largest portion of your boiler equipment investment. Not all boilers are created equal. Some basic design differences can reveal variations in expected efficiency performance levels. Evaluating these design differences can provide insight into what efficiency value and resulting operating costs you can expect. However, every boiler operates under the same fundamental thermodynamic principles. Therefore, a maximum theoretical efficiency can be calculated for a given boiler design. The maximum value represents the highest available efficiency of the unit.
If you are evaluating a boiler where the stated efficiencies are higher than the theoretical efficiency value, watch out! The efficiency value you are utilizing may not truly represent the fuel usage of the unit.