Stirling engine micro CHP
IDGTE (Institution of Diesel and Gas Turbine Engineers), 1998
Combined Heat and Power (CHP) has significant potential for
the more efficient use of fossil fuels and the reduction of CO2 and other
polluting emissions. It also offers the possibility of reduced infrastructure
requirements, (and consequent environmental impact) both in terms of large scale
generators and the associated transmission and distribution facilities, by the
nature of "embedded" generation. Indeed, the evolution from central
generating plant to distributed generation is seen by many as a natural response
to environmental demands and to the commercial pressures imposed by an
increasingly competitive market.
In the UK, economic considerations limit existing CHP
technologies to the size range of 30kWe and above, although tax advantages make
15kWe (and even smaller) viable in some countries. This is primarily due to the
high unit maintenance and capital costs of equipment. The internal combustion
engines generally applied are of limited durability, reliability and efficiency
and produce relatively high levels of noise and air pollution.
Stirling Engines offer better energy efficiency and reliability, lower
exhaust emissions and noise levels. They also permit a greater flexibility than
internal combustion engines in the choice of fossil fuels and alternative
renewable energy sources. Stirling engines are potentially prime movers in CHP
systems on the micro scale, operating effectively at outputs as low as 800We.