Energetic Stirling Engines

Stirling engines produce both - heat and electricity - with a high total efficiency of up to 90 percent. Now, companies try to enter the market for household heating. Market leader is WhisperGen of New Zealand which claims having sold some 400 units to households in the UK and the Netherlands. UK utility Powergen wants to sell some 80.000 units in the next five years, reports Bernward Janzing in Der Spiegel (27.11.2006). The high efficiency has a drawback, at least from an engineer's point of view: Electricity for home use or supplied to the grid is only possible when the heat is on. Hence, some challenge for decentralized power generation. The German firm Solo, located near Stuttgart, started the first series production of the Stirling engines in 2001, but lost touch to the market and sold only 150 units.