Peter Lynn ARCHIVE
Despite 100s of millions of dollars spent on trying to commercialise modern Stirling engines in 1987 there were no commercially mass-produced engines for the consumer market. Yet the technology offered many advantages over the norm at the time.
Don Clucas aimed to change that. Following inspiration from Peter Lynn, Don began working on the design of a commercially viable Stirling engine as the subject of his engineering PhD project. In 1987, he began in Peter Lynn’s Ashburton workshops and later moved to the University of Canterbury to make use of the university’s extensive resources.
After exhaustive market research he decided a quiet, clean, efficient, diesel fuelled battery charger and water heater for yachts and motor launches to be the ideal for a fledgling startup. These would replace the thumping and smelly diesel engine used for house battery charging. This decision would eventually lead to the 800 watt DC WhisperGenTM which was manufactured in Christchurch by Whisper Tech Ltd., incorporated in 1994.
Once established, Whisper Tech Ltd. changed focus to Micro Combined Heat and Power (microCHP) units for domestic use, a power station in your kitchen! The market in Europe and Britain was a massive opportunity. The AC WhisperGenTM (models on display) replace the home’s gas fired heating system and as a byproduct of heating the home and water, generates electricity to be used in the home or exported to the grid for a fee. This is a very efficient means of generating electricity, resulting in lower CO2 emissions and better fuel utilization. More than 90% of the natural gas fuel energy is used in the home, compared to ~40% for a large remote central power station where heat from the steam turbine and electricity transmission loss is dumped to the air or river, resulting in ~60% waste as opposed to ~10%!
If these microCHP’s could be mass produced they would provide a significant proportion of total national electricity need, they would also reduce the need for transmission line investment, number and size of central power stations and the homeowner’s energy cost.
As the AC WhisperGenTM design took shape, more investment for commercialisation became available from electricity companies and the project moved out of the University when Whisper Tech Ltd. was formed in 1994. At its peak, the startup company employed more than 120 staff. DC WhisperGens for yachts were first manufactured, and more than 2000 units were sold. As of 2023 some were still operating in customers vessels. The investors’ primary focus was for the massive microCHP market in Europe, so research and development investment were refocussed and commercial production of the DC WhisperGen ceased around 2005.
After considerable investment and nearly 10 years of development by a dedicated team, Whisper Tech Ltd. became the world's leading manufacturer of domestic microCHPs. Mass manufacture needed to be closer to the primary European market, so a joint venture was established with a massive Spanish cooperative. A complete manufacturing plant to mass produce the re-engineered AC WhisperGen was established. When ready to begin mass manufacturing the 2008 financial crisis impact hit and killed the market. The cooperative closed the doors to the factory, never to be reopened. Shortly after Christchurch was hit by two destructive earthquakes and, sadly, Whisper Tech Ltd. in Christchurch closed its doors in 2012.
On display are several design variants of the AC WhisperGen, as this was an innovative project with no existing products to learn from, six iterations were made, most of which were produced in small numbers and installed in European homes for market and product development.
Peter Lynn for the Roger Mahan Heritage Centre, July 2025
