Interconnects costs

Keusseyan, R.L., Amey, D.I., and Horowitz, S.J., New low cost interconnection materials for high frequency MCM applications, IMAPS Multichip Module Conference, Denver, CO, 1998. 

In the early 1970s, the first companies to apply low cost, mass production techniques to photovoltaics, a technology that had previously been considered an exotic aerospace technology, emerged. These techniques included the use of electroplated and screen printed metal paste electrical conductors, reflow soldered ribbon interconnects, and by 1977, low cost, automobile windshield-style, laminated module constmction. Such processes benefitted from a substantial existing industrial infrastmcture, and have become virtually ubiquitous in the present PV industry. 

To increase the impedance of the network, a series resistor or reactor is sometimes used to contain the fault level of a system within a desirable limit. This may be required to make the selection of the interrupting device easy, and from the available range, without an extra cost for a new design as well as an economical selection of the interconnecting conductors and cables. Such a situation may arise on HV >66 kV or EFIV > 132. kV transmission networks, when they are being fed by two or more power sources, which may raise the fault level of the system to an unacceptable level. The cost of the interrupting device for such a fault level may become disproportionately high, and sometimes even pose a problem in availability. 

The normal practice of all leading manufacturers is to keep the same bus and enclosure sections for the outdoor and indoor parts of the bus system. This is to retain simplicity in design and ease of jointing and interconnections. But this may prove to be a costly arrangement, as now the indoor section of the bus system will have to be... 

Instrument and Plant Air Systems. A typical setup for a large plant could include three to four 50% instrument air compressors and two 100% plant air compressors, with steam drives for normally operated units and electrical drives for spares. Common practice would provide an interconnection to allow makeup from plant air into instrument air, but not vice versa, and two sets (two 100% driers per set—one on-stream and one regenerating) of 1007c instrument air driers. Two main receivers on instrument air near the compressors with several minutes holdup time and satellite receivers at process trains would be likely and proper for feasibility cost estimating. 

Rossiter and Douglas (1986) state that the first step in process design is to generate a basic structure for the flowsheet i.e. the choice of unit operations and interconnections which can be analysed, refined and costed, and then compared to alternatives. Thus, the generation of an industrial crystallization flowsheet gives rise to a number of optimization problems for which a systematic hierarchical decision process for particulate systems was proposed ... 

Ceramic boards are currently widely used in high-performance electronic modules as interconnection substrates. They are processed from conventional ceramic precursors and refractory metal precursors and are subsequently fired to the final shape. This is largely an art a much better fundamental understanding of the materials and chemical processes will be required if low-cost, high-yield production is to be realized (see Chapter 5). A good example of ceramic interconnection boards are the multilayer ceramic (MLC) stractures used in large IBM computers (Figure 4.11). These boards measure up to 100 cm in area and contain up to 33 layers. They can interconnect as many as 133 chips. Their fabrication involves hundreds of complex chemical processes that must be precisely controlled. 

An example of such an integrated home project still under construction is given in Chapter 6.3, which describes how in South West Germany about 1200 households will be interconnected in a cost-friendly way to share comfort, service and security-related functions. 

Monolithic column — The trend to use shorter columns in liquid chromatography means that the resultant lower separation efficiency is of concern. One way to improve HPLC separation efficiency on a shorter column is to reduce the size of the packing material, but at the cost of increased backpressure. Another approach to improve performance is increasing permeability with a monolithic column. Such a column consists of one solid piece with interconnected skeletons and flow paths. The single silica rod has abimodal pore structure with macropores for through-pore flow and mesopores for nanopores within a silica rod8182 (Figure 12.1). 

Cost varies significantly based on siting and interconnection requirements, as well as unit size and configuration. 

Lanthanum chromite is the most common base for SOFC interconnects, but chromites of other lanthanide elements have also been used [43, 45, 46, 48, 54, 55], Although the conductivity of calcium-doped gadolinium chromite for low calcium contents is in the upper range of conductivities for lanthanum chromite, other nonlanthanum chromites typically have lower conductivities. However, the use of other lanthanides provides benefits in controlling the phase transformation temperature and in potential cost savings [48],... 

The difficulty and high cost of the fabrication of ceramic interconnect materials is their primary disadvantage and has led to recent emphasis on metallic interconnects, which will be discussed in the next section. 

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