In a pioneering development, scientists have engineered a “micro heat engine” that pushes the boundaries of the Carnot limit, historically regarded as the peak of efficiency for heat engines. This microscopic scale engine, propelled by a single colloidal particle and controlled by laser and electric field manipulations, achieves efficiencies approaching 95% of the Carnot benchmark. This finding defies the traditional view that high efficiency and high power cannot coexist due to the inherent compromise between power and efficiency. Such innovation hints at the possibility of future devices with improved energy efficiency.
Traditionally, the quest to create a heat engine that can deliver maximum power without sacrificing efficiency has posed a formidable challenge in the realms of physics and engineering. The Carnot limit, a theoretical boundary, dictates the maximum efficiency attainable by practical heat engines in converting heat into useful work.
Recently, a team from the Indian Institute of Science (IISc) and the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) has made a significant leap forward by developing a micro heat engine that surpasses this boundary at the laboratory scale. Their research has been published in the respected journal Nature Communications.
“To achieve what was previously deemed unattainable—simultaneous high efficiency and power—has now been demonstrated as feasible,” remarks lead scientist Ajay K Sood, National Science Chair Professor at the Physics Department, IISc, and the Principal Scientific Adviser to the Government of India.
Exploring the Power-Efficiency Dilemma
Heat engines function by converting thermal energy into mechanical work, similar to the action of moving a piston. The ideal of 100% efficiency, as posited by French physicist Sadi Carnot in 1824, dictates that no heat should be lost when the process is reversible—when the piston returns to its initial position.
Theoretically, this could only occur in an infinitely slow process, which would result in a power output of zero, rendering the engine effectively non-operational due to the power-efficiency compromise.
Progress in Microscopic Heat Engines
“Efforts to navigate the power-efficiency trade-off began in the 1970s, with significant strides made in microscopic systems in the early 2000s. A 2017 study even claimed resolving this thermodynamic challenge was impossible,” states Sudeesh Krishnamurthy, a key researcher and former PhD student at the IISc Physics Department.
In their groundbreaking work, the research team replicated the mechanics of a conventional heat engine on a micro scale. They eschewed the traditional mix of gas and fuel in favor of a colloidal bead, employing a laser to direct its movements akin to a piston in a larger engine.
“Our micro engine is distinguished by its operation on a singular particle,” explains Rajesh Ganapathy, a JNCASR Professor and co-author of the study. The diminutive size of the engine is approximately 1/100th the diameter of a human hair, he notes.
Advancing Towards Greater Efficiency and Power
By employing a rapidly alternating electric field, the researchers managed to cycle the engine between two states, substantially reducing heat waste and nearly reaching the Carnot limit’s efficiency.
Krishnamurthy elucidates, “We have managed to decrease the time for heat distribution with the introduction of the electric field. This accelerated distribution permits the engine to maintain high efficiency while also delivering substantial power output, even at elevated operational speeds.”
Prospective Applications
Previously, the team had designed a high-power engine powered by a live bacterium. This time, they substituted the bacterium with an electric field, enhancing particle movement within the colloidal medium and boosting the system’s longevity.
Their experimental findings indicate that under specific conditions, it is feasible to achieve high efficiency alongside high power, a significant stride that could lead to the creation of more energy-efficient devices.
“We have now opened a pathway that many scientists had nearly resigned to being closed due to the thermodynamic barriers established by Carnot,” Sood asserts with an eye towards the future. “The upcoming challenge is to translate this micro-engine concept into a practical application.”
For reference: “Overcoming power-efficiency tradeoff in a micro heat engine by engineered system-bath interactions” by Sudeesh Krishnamurthy, Rajesh Ganapathy, and A. K. Sood, published on 27 October 2023 in Nature Communications.
DOI: 10.1038/s41467-023-42350-y
Table of Contents
Frequently Asked Questions (FAQs) about micro heat engine
What is the Carnot limit and how does the new micro heat engine relate to it?
The Carnot limit represents the maximum theoretical efficiency for a heat engine, as defined by the laws of thermodynamics. The new micro heat engine developed by researchers challenges this limit by achieving efficiencies close to 95% of the Carnot benchmark, which was previously thought to be unattainable, especially at high power outputs.
How does the micro heat engine work?
The micro heat engine operates using a single colloidal particle, which is directed by a laser beam and manipulated through an electric field. This approach allows the engine to convert heat into work at a microscopic scale with high efficiency and power.
What implications does the development of the micro heat engine have for the future?
The development of the micro heat engine has the potential to lead to more energy-efficient devices. It demonstrates that it is possible to achieve high efficiency and power simultaneously, challenging the traditional power-efficiency tradeoff, and could influence the design of future energy systems and devices.
Who conducted the research on the micro heat engine?
The research was conducted by a team at the Indian Institute of Science (IISc) and the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR).
Where was the study on the micro heat engine published?
The study on the micro heat engine was published in the journal Nature Communications on 27 October 2023.
More about micro heat engine
- Overcoming Power-Efficiency Tradeoff in Micro Heat Engines
- Carnot Limit and Its Implications for Heat Engines
- Advances in Thermodynamics: Micro Heat Engines
- Indian Institute of Science (IISc) Research
- Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR)
5 comments
I’m amazed how the researchers at IISc are pushing the limits it’s incredible to think we can now challenge the Carnot limit with this new heat engine technology!
wow just read the study and it’s mind-blowing that they’ve managed to get efficiency so close to Carnot’s limit, great job to the team at JNCASR.
the potential for energy efficiency is huge here, i mean if we can actually apply this tech, it could change a lot of things in how we use energy but lets not get ahead of ourselvs need to see more research.
congrats to Professor Ajay K Sood and his team this is a significant milestone in thermodynamics and I’m proud to see this kind of work coming out of India.
interesting article but i have to wonder how practical this is gonna be for everyday applications need to see more about how it can be implemented.