Monthly Archives: September 2011

Microwave usefull in new technology to re-use waste heat

Chemists at Oregon State University have developed a new technology that uses thermoelectric materials which capture waste heat and convert them into electricity. The findings were published in Materials Research Bulletin.

Momentarily there is a lot of interest in new technologies that capture and convert this heat into electricity. It makes sense when you think that more than 60% of the energy produced by cars, machines and industry around the world is lost as waste heat. New methods of harnessing this heat and converting it into electricty seem to be popping up everywhere.

Thermoelectric power generation, researchers say, is a way to produce electricity from waste heat – something as basic as the hot exhaust from an automobile, or the wasted heat given off by a whirring machine. It’s been known of for decades but never really used other than in niche applications, because it’s too inefficient, costly and sometimes the materials needed are toxic. NASA has used some expensive and high-tech thermoelectric generators to produce electricity in outer space.

Now researchers at Oregon State University have discovered that the microwave also could play a crucial role in a new technology to improve energy efficiency. The microwave can be used to make a group of compounds called “skutterudites” that convert waste heat into power in mere minutes, instead of the days the existing process took, according to an Oregon statement. Most people know that you are not supposed to put metal in the microwave, because it will spark. But powder metals are different, when heated up 1,800 degrees for a few minutes, they produce promising results.

The research is being continued, it is believed that ultimately a range of different compounds may be needed for different applications of thermoelectric generation.


Carbon Trust advises businesses to re-use waste heat

The Carbon Trust has advised the UK’s businesses in a published booklet to recover their waste heat and re-use it in order to cut their energy bills.

The organisation launched a new guide to the technology, the Heat Recovery Overview Guide, last week. Richard Rugg, Director of Carbon Trust Programmes, said: “Waste heat and you are wasting money. Even though it’s been slightly warmer outside, there’s still plenty of opportunity to make heat savings inside. From office-based businesses to retailers and manufacturers, there are significant opportunities to recover and reuse heat, save money and boost your bottom line”.

The booklet expands on its previous advice on trimming refrigeration costs, which the Carbon Trust said in July could make up 70 per cent of a small business’ energy spend. An average boiler loses 25 per cent of its heat, making it a prime candidate for energy saving. But the guide also suggests recovering heat from server rooms, cooling equipment and ventilation systems in order to reduce demand for heat energy. Installing boiler flue economisers in an office with annual energy bills of £15,000 could pay back in just four years, the Carbon Trust said, while fitting a 70 per cent efficient plate heat exchanger in a typical office is likely to cut total gas consumption by 38 per cent.

For a typical new-build 250-person office, installing a de-superheater to capture heat from cooling equipment could cut £1,000 from gas bills by providing energy for space heating. The Trust advises that supermarkets and convenience stores could use heat recovered from refrigeration units to provide 75-90% of their hot water needs – equivalent to 2 or 3% of their total CO2 emissions.

The guide is free, and includes a useful, simple checklist and examples of best practice, and can be downloaded from the Carbon Trust website.


Entrepreneurs set up new bio-diesel plant

Three industrial consultants have invested more than £80,000 in a new business venture to create a bio-diesel plant on the outskirts of Worcestershire’S Stourport. They plan to supply their product to major oil companies such as BP and Shell and are aiming at £2 million (€2.3 million) in sales in year one.

On a gap year cycling around the world engineers Geoff Cunningham and one of his former colleagues began thinking about the future of this planet and if there was anything they could do to help. Using their engineering background, they looked at renewable fuels, and said they spotted a gap in the market where they could use cooking oil to create biodiesel. Last October, together with another former colleague, Organic Drive was founded.

The new 4,500sq ft production facility is now operating at full capacity, producing 100 tonnes a week of biodiesel from the used cooking oil. “There has to be a minimum of five per cent biodiesel blended into all main fuels so the market is exponential and, in the UK, there are currently very few producers,” said Duncan Morrison, who previously worked for BMW and Rolls Royce. “Utilising the expertise of Cambridge University’s Chemical Engineering Department, we have developed a number of process innovations that allow us to reduce yield losses significantly. Basically, this means we can make it cheaper than anyone else.”

The company is planning an expansion project and is currently working to obtain funding from Wyre Forest District Council to help finance this.


Recycled newspapers as car fuel

Scientists from Tulane University in New Orleans have found a way to convert newspapers and other plant based materials into car fuel.

The research of the scientists has hit upon a bacterial strain, Clostridium, TU-103, that chomps away at the cellulose in old newsprint, turning the organic material into butanol, a bio-substitute for the gas tank.

“Cellulose is found in all green plants, and is the most abundant organic material on earth, and converting it into butanol is the dream of many,” says Harshad Velankar, a postdoctoral fellow in the lab of David Mullin, associate professor of cell and molecular biology at Tulane University. “In the United States alone, at least 323 million tons of cellulosic materials that could be used to produce butanol are thrown out each year.”

Other strains of Clostridium have been used to produce butanol before, but they’ve had to be genetically engineered to do so. Others can produce butanol, but not in the presence of oxygen, while still others must break down the cellulose into sugars first. And some can break down cellulose but don’t produce butanol. Mullins team identified their strain in animal droppings, cultivated it and developed a new methodology (for which the patent is pending) for using the bacteria to produce butanol without having to isolate it from oxygen.

Butanol is touted as an alternative to ethanol because it can be used in automobiles without modification, it contains more energy than ethanol and it can be distributed through existing fuel pipelines (although there are concerns about its toxicity).

The team is currently experimenting with old editions of the Times Picayune newspaper. “In addition to possible savings on the price per gallon, as a fuel, bio-butanol produced from cellulose would dramatically reduce carbon dioxide and smog emissions in comparison to gasoline, and have a positive impact on landfill waste,” says dr. Mullin.