Rı Heat sink R&D is locusing at present on heat exchanger concepts based on carbon loam materials. These open celled carbon loams have demonstrated high heat transfer coefficients (over 11000W/m2K) that are an order of magnitude greater than conventional materials. ORNL presently is developing a second-generation loam heat sink. Poco Graphite in Decatur, Texas has obtained rights from ORNL to commercialize the material which is seen as a major new candidate lor a variety of cooling applications. High-temperature materials: Another advanced materials project is headed by Teledyne Continental Motors in conjunction with Titanium Products, 3-One-2, and Consolidated Technologies. The objective is to develop high-performance materials that can achieve a 450 ° F component cycle temperature increase (over fırst generation designs) to improve thermal efficiency performance by a factor of over 120%. □ DOE emphasizes that the Advanced Microturbine Systems program was organized to take flexible approach to possible changes in design concepts as the studies progress. While the plan is for concept development to continue through FY 2004 the door is theoretically open to new innovative ideas through FY 2005 □ Projects being worked on by this team include developing a low-cost process lor pressure consolidation of powder nickel superalloys; designing a flexible pattern môld process to make possible application of powder consolidation lor net shape components; and applying titanium silicon carbide lor stationary turbine stage components. Overall goal is to have some, if not all, of such demanding new technology available lor use in prototypes ready lor operational tests in a fairly short time period. The aim is to spend the last one to two years of the program in field tests of such equipment spanning some 8000 hours each. Demonstrations are vital: Such demonstrations are vital, DOE points aut, since microturbine generators "are relatively new and untested in commercial applications. Users have no independent, statistically signifıcant data on performance, reliability and life of ECOGENERlıTION WORLD microturbines far comparison with reciprocating engine characteristics and grid supplied electricity." A major roadblock at this time, says DOE, is !hat much of the existing test data on these machines "is considered proprietary and not to be widely shared. From the customer's standpoint the reliability and durability of microturbines remains unproven." There is a great need to gather data on microturbine systems running in a variety of environments, operating modes and utility interconnections. Thus, DOE' s program anticipates extensive reliability and durability (RAMD) testing. With this in mind DOE program organizers note that while government support is planned lor 8000-hr field tests, funding lor lollow-on RAMD studies will be considered "at that point in the program." Door open ta new concepts: DOE emphasizes !hat the Advanced Microturbine Systems program was organized to take flexible approach to possible changes in design concepts as the studies progress. While the plan is lor concept development to continue through FY 2004 the door is theoretically open to new innovative ideas through FY 2005 {through at this juncture there are no plans to go beyond FY 2004). Program managers emphasize that there is leeway lor applicants to propose new concepts and preliminary designs based on lessons learned from on-going RD&D that could impact on the design, fabrication and testing of advanced microturbine components, subsystems and integrated systems. Once systems reach the demonstration phase, says DOE, they should be tested lor a minimum 4000 hours of operation. And the demonstration should aim to resolve critical engineering or institutional barriers. Far example, considering the widespread perception of utility interconnection as a barrier to the use of microturbines, it is expected the most of the demonstration projects will address !his issue. lnterconnection problems: Another concern is that interconnection standards vary from one utility to another. Doe notes it has feedback from a number of project developers who report having to cope with standards that "require them to use outdated equipment, undertake costly engineering studies and go through lengthy approval procedures." On the other hand many utilities worry about maintaining reliable grid operations lor customers located on feeders where distributed power systems have been installed. The utilities also worry about worker safety issües. Some answers hopefully will result from studies by the lnstitute of Electrical and Electronic Engineers to develop standard interconnection protocols lor distributed generation systems.As more microturbine unite go into operation in the field, service experience should be providing a betler understanding of the safety and reliability needs of grid interconnection. Far instance, DOE points aut, "modification of protective relaying schemes may be needed at both ends of the circuit to insure proper coordination between upstream and downstream protective devices and to fully protect line. Source: Gas Turbine World
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