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This new way to refrigerate has zero global warming potential

In a study published in Science, researchers introduced the concept of ionocaloric cooling as a potential new method for reducing mercury emissions.

In conventional refrigeration systems, heat is removed from a space by means of a gas that cools as it travels to greater distances. Our preferred gases have an adverse effect on the environment, despite the procedure’s efficiency.

To force a substance to absorb and release heat energy, however, can be done in a variety of ways.

Energy is either stored or released as a material changes phase, such as when solid ice melts into liquid water, and this phenomenon is being exploited in a novel technique developed by researchers at the University of California, Berkeley and the Lawrence Berkeley National Laboratory in the United States.

A frozen block of ice will eventually melt if its temperature is increased. Perhaps it is not as obvious to us that melting effectively cools its environment by absorbing heat from its surroundings.

When ice is treated with a small amount of charged particles, or ions, it can begin to melt without the addition of additional heat. The practise of spreading salt on roads to prevent ice from forming is a common illustration of this principle in action. The ionocaloric cycle makes use of salt to change the phase of a fluid and thereby cool its surroundings.

According to Science Alert, mechanical engineer Drew Lilley of California’s Lawrence Berkeley National Laboratory said, “The landscape of refrigerants is an unsolved problem.” No one has come up with a better way to keep things cool that is also efficient, harmless, and environmentally friendly.

We believe that, with proper implementation, the ionocaloric cycle can achieve all of these aims.

Researchers modelled the ionocaloric cycle theory to show how it could be competitive with or even more efficient than existing refrigerants. If an electric current were to flow through the system, the ions within it would be displaced, causing the melting point of the material to shift in the same way that temperature shifts do.

The researchers also tried using a salt made of sodium and iodine to melt ethylene carbonate. A common organic solvent, carbon dioxide is used in its production and lithium-ion batteries benefit from it as well. As a result, the system’s global warming potential might be negative instead of zero.

The experiment, which used less than one volt of charge, resulted in a temperature shift of 25 degrees Celsius (45 degrees Fahrenheit), which is more than has been achieved by existing caloric technologies.

Mechanical engineer Ravi Prasher from the Lawrence Berkeley National Laboratory said, “There are three things we’re trying to balance: the GWP of the refrigerant, energy efficiency, and the cost of the equipment itself.”

In today’s vapour compression systems, gases with a high global warming potential (GWP) are typically used. Countries that have signed the Kigali Amendment have agreed to reduce their production and consumption of HFCs by at least 80% over the next 25 years, and ionocaloric cooling could play a significant role in this effort.

Scientists now need to bring this technology out of the lab and onto commercially viable platforms so that it can be scaled up without incident. In the future, these systems could be used for both heating and cooling.