Cell room systems design

The part of the electrical supply system of direct relevance to cell-room area design is that involved in the provision of direct cmrent to the cells. This section covers the transformers, rectifiers, and buswork that handle that duty. Transformers do not provide direct current (DC), but they are included because of their intimate association with rectifiers. The transformer-rectifier installation is usually adjacent to the cell room but in a physically isolated area. Design, operation, and maintenance of these systems are all matters for specialists. This book does not discuss these subjects. Standard publications [10] cover them in detail, along with the extensive instrumentation and control systems that are necessary. 

Frequent shutdowns can have a cumulative deleterious effect on membranes and on the performance and useful life of electrode coatings. They should be avoided. If the current is interrupted for any reason, there are several actions necessary to mitigate this deterioration. Shutdown requirements and system provisions are, therefore, an important part of cell room design. 

A plant performance test will normally be carried out over a defined period (usually 48 hr or longer) during which the cell room will be operated steadily near the design load. To enable this, it must be established before the test that all peripheral systems are capable of steady operation at the required throughput. 

Operation under pressure would seriously aggravate the consequences of a chlorine leak in the cell room. Outdoor construction or the use of some of the practices associated with contained storage systems (Section 9.1.8.2C) would help to relieve the hazard. In any event, there would have to be a complete rethinking of many operating practices as well as major revisions in design. 

Other chapters deal with utility systems, cell room design and arrangement (with an emphasis on direct current supply), alternative processes for the production of either chlorine or caustic without the other, the production of hypochlorite, industrial hygiene, and speculations on future developments in technology. There is an Appendix with selected physical property data. 

One of the most frequent comments by reviewers of the first edition has been to commend its clarity. To make the many topics encompassed by fuel cell technology clear to newcomers was one of our most important aims. Nevertheless, there is always room for improvement, and many changes have been made to make the text and diagrams even clearer. Many new diagrams have been added, and others improved. We have added an entirely new chapter that brings together the issues involved in system design and analysis. This introduces concepts such as well-to-wheel analysis, which is now a vital element of systems studies in transportation appUcations. In this new chapter, practical examples of both stationary and mobile applications completes our analysis of fuel cell systems. 

Lick Observatory. The success of the LLNL/AVLIS demonstration led to the deployment of a pulsed dye laser / AO system on the Lick Observatory 3-m telescope (Friedman et al., 1995). LGS system (Fig. 14). The dye cells are pumped by 4 70 W, frequency-doubled, flashlamp-pumped, solid-state Nd YAG lasers. Each laser dissipates 8 kW, which is removed by watercooling. The YAG lasers, oscillator, dye pumps and control system are located in a room in the Observatory basement to isolate heat production and vibrations from the telescope. A grazing incidence dye master oscillator (DMO) provides a single frequency 589.2 nm pulse, 100-150 ns in length at an 11 kHz repetition rate. The pulse width is a compromise between the requirements for Na excitation and the need for efficient conversion in the dye, for which shorter pulses are optimum. The laser utilizes a custom designed laser dye, R-2 perchlorate, that lasts for 1-2 years of use before replacement is required. 

The model molecules which are solid at room temperature (except for benzene), were evaporated from a source consisted of a borosilicate glass container with a small opening, like the design of a Knudsen cell. The source was mounted inside a heatable and coolable copper shaft, that could be inserted to the vaccum system through a load-lock arrangement. Upon heating, the pressure was... 

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