Why a steam engine?
In a steam engine there is no internal combustion; ie there is no explosive combustion of fuels inside a cylinder that produce high pressure wave fronts, unburnt hydrocarbons, nitrous oxides, noise and other issues confronting internal combustion engines.
Steam engines combust fuel in the most efficient manner possible, in a furnace, and then use the energy released to 'raise steam'. It is the mass of steam that is then injected into the cylinder to expand and drive the piston. Because externally fired engines are very tolerant of fuel quality the Pritchard S5000 creates the opportunity to directly combust 'low grade' solid fuel and create useful rotary power, using the most common, cheap and non-toxic working fluid, water. Low grade fuels suitable for direct combustion could include wheat straw, nut shells, sawdust or any local weed species or specially grown firewood crop.
The patented engine of the S5000 has done for steam engines what IBM did for the computer, made it (PC) personal.
The Pritchard S5000 prototype, technically known as an "externally fired, biomass fuelled, double action, single cylinder uniflow engine", is not the result of a backyard design process.
Ted Pritchard designed and built a series of advanced steam engines throughout a more than 50 year career as an engineer.
In the 1970's Ted's steam powered car (a 1967 Falcon powered with a Pritchard V-Twin steam engine burning kerosene) caused something of a sensation and was a very common sight in Melbourne, becoming famous following numerous appearances in newspapers and on television news around the country. In 1974 this car was tested for tail pipe emissions by the Ford Motors facility in Geelong where the emissions measured were so low (including for instance zero unburnt hydrocarbons) that it would have passed the Euro 2 emissions standards not introduced into Europe in 1998.
In 1979 the most advanced V-Twin engine was completed and tested before the venture ran out of funding. Uniflow Power has the advanced V-Twin and is intending to eventually refurbish it to assess its suitability for use as a 30kW stationary generator.
Initially however the development program is focused on product development based on the smaller, biomass fired, single cylinder S5000. The S5000 is actually a combination of two notable advances in steam and engine technology. The highly efficient, small furnace and boiler and the advanced and unique double acting uniflow engine. Because there is no internal combustion, the S5000 is very quiet.
In applications where it is being used to replace a diesel or petrol powered generator the low noise of the S5000 will be an enormous improvement in comfort and utility, allowing operation of the device indoors (with appropriate ventilation or external flues) and right beside other activity such as community or health centres, schools or workplaces, without the imposition that the roar of internal combustion generators can create.
The patented boiler does not use an accumulator, steam chest or 'pressure' cylinder but rather is a 'flash' boiler. We call it a 'steam generator'. If the mechanical power of the engine is not needed, the small and highly efficient steam generator can be used directly to produce either wet or dry steam, and thus deliver sterilizing, distillation, process heat, hot water and space heating depending on how the steam/water circuit is configured.
The patented engine of the S5000 has done for steam engines what IBM did for the computer, made it (PC) personal. The Uniflow Power stationary engine has the potential to deliver a system that could comfortably power and heat an average suburban home, providing hot water, electricity and space heating, all from pelletised wood fuels. This is referred to as CHP, or combined heat and power.
Using high quality pelletised fuels a Uniflow CHP system should produce no visible smoke and be able to be largely automatically controlled like other modern home heating system. A program of work is also underway to develop a system that would run off natural gas for those applications where use of renewable solid fuels was not practical and where gas is available.
The existing prototype is being extensively tested while a number of industrial and mechanical design processes are underway to refine designs for market ready products.