Heat engines transform heat into mechanical energy with the corresponding efficiency of an Otto engine amounting to only about 25 percent, which is what your automobile gets.
The efficiency of heat engines powered by thermal heat reservoirs is determined by the second law of thermodynamics, one of the fundamental concepts in physics. It was as far back as 1824 that Frenchman Nicolas Carnot calculated the maximum possible efficiency limit of such engines, now known as the Carnot limit.
Now imagine a heat engine that consists of just a single calcium ion. Such a nano-sized heat engine would be far more efficient than your car engine or a coal-fired power plant because we can theoretically exceed the classic Carnot limit by manipulating the heat baths and exploiting non-equlibrium states.
A prototype of such a single-ion heat engine is currently being constructed at Mainz University.
Simulation of an Otto cycle of a single ion heat engine: The enclosed area pictures the produced work that is significantly increased by way of squeezing. Credit: Quantum, Mainz University
Calculations and simulations from last year showed for the first time that the thermo-dynamic flow in an internal combustion engine could be reproduced using individual ions. The idea was to use a calcium 40 ion, which has a diameter a million times smaller than that of a human hair, for this purpose. "Individual ions can basically act as the piston and drive shaft or, in other words, represent the entire engine," explained Johannes Roßnagel of the Quantum, Atomic, and Neutron Physics (QUANTUM) work group of the JGU Institute of Physics.
Individual ions have already been captured in Paul traps and, using laser beams and electrical fields, not only cooled and heated but also compressed.
"This means we are able to manipulate the pulse location distribution for optimum efficiency," added Roßnagel. "Exceeding the Carnot limit for a standard heat engine thus does not violate the second law of thermodynamics but instead demonstrates that the use of specially prepared, non-thermal heat reservoirs also makes it possible to further improve efficiency."
In their article, the physicists calculated the general Carnot limit for this situation. As the mechanical capacity of a single ion machine is extremely low, it can probably only be used in heating or cooling nano systems.
A single trapped ion in a linear Paul trap with special geometry: The heat engine is being realized by the divergent bars; the squeezing is being caused by establishing special electrical fields. © Quantum, Mainz University
The intention is now to actually develop the proposed single ion heat engine in initial experiments and construct a prototype in the laboratory.
Citation: Johannes Roßnagel et al. , 'Nanoscale Heat Engine Beyond the Carnot Limit', Physical Review Letters, 22 January 2014 DOI: 10.1103/PhysRevLett.112.030602
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Thinking 'I Can Do Better' Really Can Improve Performance, Study Finds
- Brain Cancer: Why Glioblastoma Is So Difficult To Treat
- Benign Bacteria Block Mosquitoes From Transmitting Zika, Chikungunya Viruses
- Some Celiac Disease May Be Due To Viruses
- Can A New Rule Trigger A Second EU Referendum? Petition 4 Millon Signatures, Nearly 12% Of Total Votes Cast
- Little To No Association Between Butter Consumption And Chronic Disease Or Total Mortality
- How A Former Naturopath Can Help Unravel The Trickery of Alternative Medicine
- " Media Silent as Concealed Carrier Stops Mass Shooting in Progress at a South Carolina Nightclub..."
- "Thank you for your support - but since the comment you refer to was advocating the shutting down..."
- "Instead of ND, substitute DD, and you have a whole other basket of charlatans - and that comment..."
- " Some parts from my second response to Nina Teicholz article ( http://www.bmj.com/content/351/bmj..."
- "Science researchers did the CARET study, to see if vitamin A could chemo-prevent lung cancer (it..."
- The Relationship Between Alcohol and Happiness
- Psst…NRDC Stoners: Your Endocrines Are Disrupted
- College Kids Mostly Blow Off Food-Label Use, Study Finds
- Blue Birds Aren’t Blue, and This is How They Fool You
- ‘Vaxxed’: The Film That No One Saw
- Vice President Joe Biden Threatens the Scientific Community
- Consensus statement: Environmental toxins hurt brain development, action needed
- New anti-cancer strategy mobilizes both innate and adaptive immune response
- Aging population is growing ranks of cancer survivors
- UK government should fund media campaigns that promote quitting, not films that promote smoking
- Report: A host of common chemicals endanger child brain development