UNSW residential cogen model to be tested in Germany

A University of New South Wales PhD student will travel to Germany in July to build on his research into improving the efficiency of residential cogeneration plants.

Christoph Ummenhofer, whose research has included modelling a super efficient, small-scale cogen system which uses a gas-powered internal combustion engine to produce electricity and heating for buildings, will spend six months at the University of Applied Sciences Landshut, after receiving a German Foreign Exchange Fellowship based on his work.

Also known as micro combined heat and power (micro-CHP), residential co-generation is a key part of Europe’s broader quest to develop modern renewable heating systems, as households look to slash power costs and governments seek to decouple their economies from politically unstable regions on which they still depend for energy.

With the added impetus of its Energiewend, Germany – where heating accounts for 40 per cent of energy consumed – leads the market in high efficiency micro-CHP technology, and is home to half of all European developers, according to Germany Trade and Invest. In June, Munich will host a Renewable Heating Forum as part of InterSolar Europe 2014.

Ummenhofer, who built a simulation of his small-scale cogeneration unit as part of his UNSW PhD, will use his time at Landshut to validate his modelling, while also using the University’s experimental co-generation plant to build on his research.

Already considered an efficient way to power, heat and cool buildings, Ummenhofer sees room for improvement in micro-CHP – particularly on smaller systems, such as those used in place of a boiler in a building’s basement, which are powered up or down multiple times a day, depending on requirements.

In particular, he hopes to find ways to minimise the energy wasted by stopping and starting the engine, particularly through looking at strategies to keep the engine ‘warm’.

“In a sense, it’s really fine-tuning of the plant but every little bit of extra efficiency helps,” he said.

Ummenhofer has modelled a system that can now be used to simulate a number of energy-saving scenarios using various software packages.

“He’s now in a position where he’s making predictions about what’s going on, but it’s always nice to be able to verify these predictions against real-world data,” said Dr John Olsen, an academic in the School of Mechanical and Manufacturing Engineering, who is Ummenhofer’s PhD supervisor.

Ummenhofer says the co-generation system in Germany is integrated into the building services and is used to provide power and heat. “I will use data from that system to verify my model,” he says.

When the six months is up, Ummenhofer will return to UNSW to complete his PhD. In an interview with RenewEconomy on Thursday, he said he would also be investigating incorporating air conditioning and refrigeration into his cogen modelling, to better adapt the technology to the Australian market.

Ummenhofer – who noted there was “a lot of potential” for renewable energy in the Australian market – said that using recaptured heat to generate cold for refrigeration and air con was an increasingly interesting area of development in micro-CHP.