Thermogalvanic Effect: Harnessing Waste Heat
The discovery of fire was a turning point in human history, it offered portable warmth, light, protection, and a new way of preparing food. It was also one of mankind’s most successful attempts to harness energy. Because energy is almost always lost in the harvesting phase, researchers around the world have spent decades seeking ways to harness this wasted energy.
Researchers at MIT and Stanford have found a new way to transform waste heat into electricity. Electricity is considered high-grade energy because it can be converted into other forms of energy for use and storage without significant losses. Thermal energy is low-grade energy, which means that attempts to transform heat back into other forms of energy is costly and inefficient. Most of the time, thermal energy is written off as waste heat and released into the environment. Converting low-grade energy back into high-grade energy is an uphill battle, but there are new thermoelectric products that could be our best bet. Efficient and low-cost thermal energy-harvesting systems are needed to utilize the tremendous low-grade heat sources.
The new technology uses available materials and could be used to recycle the large amounts of wasted heat generated in industrial processes and electric power plants. The new system allows waste heat to raise the temperature of a battery, and thanks to the thermogalvanic effect, the battery can now be charged at a lower voltage than would normally be required. The battery is then cooled down, and because the charging voltage is lower at high temperatures than at low temperatures, once it has cooled the battery can deliver more electricity than what was used to charge it. That extra energy, of course, does not just appear from nowhere: it comes from the heat that was added to the system.
Imagine the potential of thermoelectric-powered devices, Engineers are working diligently to find the most cost-effective approach and I don’t know about you but just the possibility of charging a cell phone by using body heat is something to look forward to!
The Plastic Strategy
The great plastic debate - not only in politics but also in everyday conversations people are demanding we save the environment. Many argue that the world should do away with all plastic use, which unfortunately is not realistic. Plastic is necessary for highly perishable foods as well as high moisture content products. It is widely known that the plastic consumption of the world is out of control but, if we were to stop using plastics for food, the amount of food spoilage would be over 20-times the waste of the packaging. The creation of new technology is required if we want to do more than just clean up the mountains of plastic waste and hope the next generation is more considerate in their consumer-driven lives.
Despite the challenges related to plastic waste, demand continues to grow. Engineering goals have started to shift toward a new plastic strategy: bioplastics. The traditional biodegradable plastics just are not degrading fast enough to keep up with demand. To understand the difference between the two types of plastics, clarifying the terms will help:
Bio-based plastics are all about renewable raw materials. Renewable raw materials such as sugar, corn, or wheat are used to create the plastic. Polylactic acid (PLA) is a good example: it is a 100% bio-based plastic and today mostly produced from corn. In contrast, biodegradable plastics have been designed to decompose and degrade under the right conditions, for example, when in contact with soil, compost or even water.
Engineers are committed to finding renewables that are still durable, recyclable, and reusable. Already bio-based plastics are being used in car parts, packaging, even children’s toys. The next step engineers are trying to achieve on an industrial scale is using these plastics as a renewable diesel. They are taking waste plastic and turning it back into a raw material for fossil refining. To do so plastics are either chemically or mechanically recycled. Mechanical recycling reduces the plastic into granules, but it cannot be reused for food packaging as there are impurities. Chemical recycling breaks the plastic down into a liquid similar to crude oil. These plastics are free of impurities making this process the optimal choice.
Environmentalists have been raising awareness for a plastic-free future. One such movement is saving sea turtles by switching from plastic straws to paper ones. While filled with good intention this effort completely defeats the purpose. By switching to paper, it requires more trees to be cut down which results in decreased oxygen (that vital substance) needed by every living creature on the planet. The practice of conservation is a good one, and engineers have been hard at work securing a better future by creating a way to reuse the plastics we recycle.
Scientists Find New Behavior of Water
The current state of the art theoretical models and computer simulations have predicted a fundamental asymmetry in the mechanisms by which water transports the protons from H2O, (H+) and (OH-). For nearly a century, it was thought that the mechanisms were mirror images of each other. Identical in all ways except the direction the bonds move. New research has discovered that this line of thinking is not true.
This asymmetrical movement has been extremely difficult to capture because scientists only get a glimpse of the predicted asymmetry. However, a team of researchers from New York University has devised a novel experiment for nailing down this movement. The experiment involves cooling down water to the maximum density temperature of 39 degrees. This is the temperature that asymmetry is expected to be the strongest. Using nuclear magnetic resonance to show the difference in the lifetimes of the two ions, the asymmetry became glaringly clear.
“The study of water’s molecular properties is of intense interest due to its central role in enabling physiological processes and its ubiquitous nature,” says Jerschow, the corresponding author of this study. “The new finding is quite surprising and may enable a deeper understanding of water’s properties as well as its role as a fluid in many of nature’s phenomena.”
With the theory now proven scientists can use this information to design new materials for clean energy applications. Further research will also be done using this new information to discover enzyme function in the body and to better understand how living organisms can thrive in harsh conditions, including sub-freezing temperatures. This remarkable property of water makes it a critical component of life, without this characteristic life itself would not be possible.