propane

Cyber protection for apple orchards

April 2, 2024 By EarthWise Leave a Comment

Spring frosts represent a real danger for apple orchards. The changing climate has brought about periods of unusually warm weather at times early in the year that have caused trees and other flowering plants to bloom early. For apple growers, this has made their orchards more susceptible to the damaging effects of extreme cold events.

Apple growers attempt to prevent this damage by heating the canopies of their orchards, but these efforts tend to be inefficient. Applying heat is one of the most effective methods to prevent apple flower bud damage, but it is difficult to determine when and where to apply heat in orchards.

Researchers at Penn State University have developed a frost-protection cyber-physical system that autonomously makes heating decisions based on real-time temperature and wind-direction data. Their system includes a temperature-sensing device, a propane-fueled heater that adjusts the direction where it provides heat, and an unmanned ground vehicle that moves the system through an apple orchard.

The results of tests of the system were published in the journal Computers and Electronics in Agriculture, and the findings show that it greatly reduced damage to apple tree buds in tests conducted at low temperatures, doubling or tripling the amount of time that trees were protected.

The equipment used for the study mostly consisted of off-the-shelf parts and cost about $5,000, most of which was for the vehicle. The researchers envision that even a very large orchard could be protected by multiple units guided by an aerial drone monitoring canopy temperatures. Further research will aim to bring the technology to point where it can enter the marketplace and be available to apple growers.

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Cyber-physical heating system may protect apple blossoms in orchards

Photo, posted September 6, 2017, courtesy of Sue Thompson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Better Way To Recycle Plastics | Earth Wise

November 10, 2022 By EarthWise Leave a Comment

The global accumulation of plastic waste is an ever-growing problem. At least five billion tons of the stuff has accumulated on land and sea and is even showing up in the bodies of animals and humans. Recycling plastic instead of making even more of it seems like an essential thing to do but it has proven to be extremely challenging.

The main problem is that plastics come in many different varieties and the ways of breaking them down into a form that can be reused are very specific to each type of plastic. Sorting plastic waste by plastic type is extremely impractical at large scale. Certainly, most consumers can’t do it themselves. As a result, most plastic gathered in recycling programs ends up in landfills.

New research at MIT has developed a chemical process using a catalyst based on cobalt that is very effective at breaking down a variety of plastics, including polyethylene and polypropylene, which are the two most widely produced plastics. The MIT process breaks plastics down into propane. Propane can be used as a fuel or as a feedstock for making many different products, including new plastics.

Plastics are hard to recycle because their long-chain molecules are very stable and difficult to break apart. Most chemical methods for breaking their chemical bonds produce a random mix of different molecules which would somehow have to be sorted out in order to be useful for anything.

The new process uses a catalyst called a zeolite that contains cobalt nanoparticles. The catalyst selectively breaks down various plastic polymer molecules and turns more than 80% of them into propane.

The researchers are still studying the economics and logistics of the method, but it looks quite promising.

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New process could enable more efficient plastics recycling

Photo, posted April 25, 2016, courtesy of NOAA Coral Reef Ecosystem Program via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Propane Refrigerants | Earth Wise

September 20, 2022 By EarthWise Leave a Comment

About 10% of the world’s total electricity supply is used for air conditioning. If current temperature trends continue, the energy demands for space cooling will more than triple by the year 2050. Air conditioning is a double threat to the environment. Apart from using lots of energy, ACs also make use of halogenated refrigerants that are extremely powerful greenhouse gases.

The most common space cooling appliances are split-air conditioners, which use an indoor unit and an outdoor unit connected by pipes. These split ACS mostly utilize HCFC-22 and HFC-410 as refrigerants, which have global warming potential scores as high as 2,256 – meaning they trap 2,256 times more heat than carbon dioxide.

A study by the International Institute of Applied Systems Analysis in Austria has shown that propane is a far better choice as an air conditioning refrigerant. Its global warming potential is actually less than 1 meaning it traps less heat than carbon dioxide. According to the study, if air conditioners switched to propane refrigerants, the world would avoid about a tenth of a degree Celsius of additional warming, which is a significant contribution to meeting the goals of the Paris climate agreement.

Propane-based split-ACs are already available commercially in China and India. Elsewhere, many national regulations prohibit their use, primarily due to codes restricting the use of refrigerants with higher flammability. Given the increasingly urgent need for climate action, it seems to be time to reconsider regulations on refrigerants.

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Propane — a solution for more sustainable air conditioning

Photo, posted March 24, 2021, courtesy of Phyxter Home Services via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate-Friendly Refrigerants

March 29, 2017 By EarthWise

In 1988, President Reagan signed the Montreal Protocol, which banned CFC refrigerants like Freon in air conditioners and refrigerators. The chlorofluorocarbons were the cause of a giant hole in the ozone layer, which has been shrinking ever since the ban. Unfortunately, the chemicals that replaced CFCs – hydrofluorocarbons or HFCs – have their own major problem: they are a seriously bad greenhouse gas, far worse than carbon dioxide. Last fall, an international agreement was reached by over 170 countries to reduce and eventually replace HFCs, which included 100 developing countries like China and India where air conditioning use is growing fastest.