Gulf Coast CHP - Stirling Engines

Stirling Engines
Stirling engine has the potential to be much more efficient than reciprocating engines. A Stirling engine uses the Stirling cycle, which is unlike the cycles used in internal combustion engines. The gases used inside a Stirling engine never leave the engine, and this allows great fuel flexibility such as most variations of fossil, biomass fuel and waste gases (see animation). The engine operates by converting differences in temperatures into electrical output. An external heat source is typically used to create the temperature differential, but theoretically a Stirling engine could run on chemical processes that produce cold instead of heat, such as the sublimation of dry ice or the boiling of liquid nitrogen.

In addition, these engines are extremely quiet, because no combustion takes place inside the cylinders. As a result, specialized applications like submarines or auxiliary power generators for yachts, where quiet operation is required, are some of the initial applications for Stirling engines. Recently this technology has been used for residential applications. Several utility companies are demonstrating the technology for residential applications. Electric efficiencies of more than 40 % and system efficiencies of more than 95 % have been achieved. Stirling micro-CHP packages are targeted to cost $2,500/kW (thermal + electric) compared to $1,200/kW or less for combustion turbine and IC CHP packages. Service intervals of between 3,500 and 5,000 hours (equivalent to over one year's economic operation) are expected with a product lifetime of more than six years' continuous operation. Stirling engines are pre-commercial, but are expected to contribute to residential and small business needs.

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