It’s getting harder and harder to beat the summer heat. Across the globe, temperatures are rising. While global temperatures have risen about .14 degrees per decade over the last 140 years, the increase per decade has more than doubled in the last 40 years, signaling a dramatic shift in warming. Sources overwhelmingly point to climate change as a driving factor, including the release of carbon and greenhouse gasses by humans.
To beat the heat, you’re likely turning down your A/C to keep cool. The problem with many air conditioning units, however, is that they aren’t exactly the most environmentally friendly devices. Hydroflurocarbons, which are used as refrigerants in many similar devices, contribute greenhouse gasses to the atmosphere, which can worsen climate change.
A research team with the American Chemical Society has developed a prototype device that, in the future, could replace existing air conditioning units and operate as a cleaner, greener tool for keeping cool in the summer heat.
A traditional cooling device like an air conditioner often works by using refrigerants like hydrofluorocarbons that modulate between liquid and gas states; when in a gas state, heat can be absorbed to cool a room, while returning to a liquid can help release that heat. For air conditioners, this heat is expelled outside of a home. However, despite being an efficient system, this process can release hydrofluorocarbon refrigerants into the atmosphere.
Researchers have considered solid refrigerants as an alternative to those that cycle between liquid and gasses. The main benefit of solid refrigerants is that the refrigerants won’t leak into the environment and contribute to climate change. One common type of solid refrigerant is called barocaloric material. Through the use of pressure, barocaloric materials go between solid to solid changes, changing only the internal structure of the solid. Researchers liken this process to melting wax, and the change between a “solid” solid and a less rigid solid creates a process that replicates the heat absorption and expulsion that liquid-gas transitions produce. However, this process requires significant amounts of pressure, more than can be produced in residential settings.
The ACS research team has not only identified a material that doesn’t require as much pressure as barocaloric materials, but they’ve also built a cooling system that can use solid refrigerants with about 3,000 psi of pressure, which is common in typical hydraulic systems
The research team plans to test different types of barocaloric materials to find an optimal option for their new air conditioning device.
Sources: ACS; Climate.gov