Future Tech 8 Ways We Could Recycle Our Wasted Heat

Every electrical appliance — from a humble light bulb to a MacBook Pro — leaks precious heat. Electric companies love this fact. We, on the other hand, should be looking for solutions.

Researchers at Rensselaer Polytechnic Institute teamed up with the University of Wollongong in Australia to design a new material that converts heat into electricity. They mixed zinc oxide nanoparticles (the material that makes sunscreen dry clear on your skin) with aluminum and heated it in a microwave for about three minutes. The zinc oxide conducts electricity and the aluminum makes it harder for the molecules to transfer heat. The difference in temperature between the two parts of the material sparks the electrons to start an electrical current.

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Microwave Ovens a Key to Energy Production from Wasted Heat

More than 60 percent of the energy produced by cars, machines, and industry around the world is lost as waste heat — an age-old problem — but researchers have found a new way to make “thermoelectric” materials for use in technology that could potentially save vast amounts of energy.

And it’s based on a device found everywhere from kitchens to dorm rooms: a microwave oven.

Chemists at Oregon State University have discovered that simple microwave energy can be used to make a very promising group of compounds called “skutterudites,” and lead to greatly improved methods of capturing wasted heat and turning it into useful electricity.

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New Multiferroic Alloy Magnetizes When Heated, Transforms Waste Heat Into Electricity

A team of researchers at the University of Minnesota has discovered a new alloy that can transform heat into electricity. The approach is new and uses a coil to transform the magnetic field generated by the alloy.

“This research is very promising because it presents an entirely new method for energy conversion that’s never been done before,” said University of Minnesota aerospace engineering and mechanics professor Richard James, who led the research team.”It’s also the ultimate ‘green’ way to create electricity because it uses waste heat to create electricity with no carbon dioxide.”

The new multiferroic alloy has the chemical formula Ni45Co5Mn4Sn10, and has been composed by combining the elements at an atomic level. This material is able to undergo a highly reversible phase transformation to achieve multiferroism. During the phenomenon, in which a solid turns into another solid, the alloy changes its magnetic properties with the changing of temperature.

A small-scale demonstration at the University of Minnesota proved that the material acted as non-magnetic and then when they raised the temperature by a small amount, the same metal turned into a powerful magnet that absorbed the heat and, of course, produced electricity in the coil surrounding it.

The efficiency had been low at first due to a process called hysteresis (where the thresholds of turning into a magnet and back into a simple metal were at different temperatures). The team has however managed to reduce the hysteresis during the phase transformation.

Although still in its infancy, this technology could add up to the multitude of other thermoelectric materials and processes discovered so far and could ultimately capture most of the world’s wasted heat including that coming from cars and power plants, to enhance their efficiencies and bring down the energy costs.

Observe the powerful magnetic field generated by heating the alloy and how it attracts the small piece of metal, in the video below:

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Source: greenoptimistic
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Oil well taps wastewater for renewable energy

An oil drill in Mississippi is breaking new ground in waste heat, using unwanted water to run a generator that runs on waste heat.

ElectraTherm, which makes the waste heat generator, said the Denbury oil well near Laurel, Miss., has successfully installed its GreenMachine product and shown that it can provide 20 percent of the electric power needed for the drilling. The demonstration was funded by a $460,000 federal government grant, half of which was paid for by one of ElectraTherm’s distributors.

 

The waste heat generator can be delivered on the skid of a tractor trailer. The green machine is the actual generator while the white machine with the fans on left are used for cooling the refrigerant in the loop. (Credit: ElectraTherm)

 

Waste heat is considered a relatively untapped source of energy that could make many industrial processes, such as power generation or manufacturing, more efficient.

Electratherm’s generator is designed to operate using a relatively low-temperature heat source and produce between 30 kilowatts and 65 kilowatts. At the Mississippi well, drillers seeking new sources of oil generate 4,000 barrels of unwanted water per day. At 204 degrees Farenheit, it can operate ElectraTherms’ GreenMachine.

The generator operates using a similar principle to ground-source heat pumps. The heat from the water, or another heat source, causes a refrigerant fluid in tubes to evaporate. The pressure from that gas turns a mechanism connected to a generator to make electricity. Using fans, the gas is then cooled down back into liquid form to start the process again.

Oil wells have used waste heat to generate electricity before, but the advantage the Green Machine has in the field is that it’s portable, ElectraTherm representative Celeste Dodge said today. After one well has been drilled, it can be moved to another location. The generator in Mississippi was installed in 50 hours.

Waste heat is a free source of energy, but waste heat generators compete with grid electricity prices. In places where electricity costs 10 cents or higher per kilowatt-hour, the return on investment for a GreenMachine is four to six years, according to the company. The national average is 11 cents per kilowatt-hour. In places with cheaper electricity, such as the U.S. Southeast, there isn’t a big incentive to invest in waste heat generators without grants or policies to promote renewable energy, she said.

 

Source: cnet

 

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