One of the biggest problems faced by most industries is the waste heat. It is of particular annoyance to electronics. The waste heat can not only damage components but it is essentially a large portion of energy that is being wasted. Scientists at the University of California, Berkeley developed a nanofilm to get over that problem. This film can be built into computers, cars, and factories to capture and recycle energy from waste heat.
There are some devices that work on the thermoelectric principle to generate electricity through a temperature difference. But these require a large temperature difference. They can’t be used for smaller temperature differences like the hot and cold sides of a material.
The team from UC Berkeley wished to create a device to tap into this low-quality waste heat involving temperatures below 100° C. The newly developed nanofilm works on the principle of pyroelectric energy conversion, which can work with lower temperatures and more gradual changes. This is what makes it ideal for use in electronics.
“We know we need new energy sources, but we also need to do better at utilizing the energy we already have,” says Lane Martin, senior author of the study. “These thin films can help us squeeze more energy than we do today out of every source of energy.”
Prototype devices were built by the team to supply heat and electric fields to pyroelectric films that were only 50 to 100 nanometers thick. They then measured the temperature and the amount of electricity generated. They found that the devices managed to achieve an energy density of 1.06 Joules per cm cube, a power density of 526 Watts per cm cube, and a Carnot efficiency of 19 %. These are new records for pyroelectric energy conversion.
According to the researchers, their work is helping to improve the understanding of pyroelectric physics. This can result in improvement of the devices designed. The nanofilm can be optimized for individual systems in the future, based on the amount of heat loss and the temperature.
“Part of what we’re trying to do is create a protocol that allows us to push the extremes of pyroelectric materials so that you can give me a waste-heat stream and I can get you a material optimized to address your problems,” says Martin.
This could definitely be a breakthrough and will result in a drastic decrease in energy consumption by electronic devices.