October 22nd, 2020 by Steve Hanley
The issue is pretty clear. If the global community does not find a way to drastically reduce greenhouse gas emissions within the next decade, the Earth will continue to warm. Higher average temperatures will melt the polar ice caps, raise the level of the oceans by several feet, and make more powerful storms and wildfires everyday occurrences. The upshot of all these changes will be an environment that is inhospitable to human habitation.
We will need new ideas and new technologies to preserve the Earth as a place where those who come after us will be able to thrive. Fortunately, those new ideas and technologies abound. The trick is knowing which ones to embrace and which to ignore. Two of the more promising ones involve using cold water from the oceans to cool buildings and better ways to remove carbon dioxide from exhaust streams.
Sea Water Air Conditioning
According to new research published in the journal Energy Efficiency, water in the oceans below 700 meters has a temperature of between 3 and 5 degrees Celsius. Just one cubic meter of that water has the cooling capacity of 21 wind turbines or a solar power plant equal to 68 football fields. District heating and cooling is virtually unknown in the US where suburban sprawl is the norm but is more common in European cities where the built environment is especially dense.
The idea from an International Institute for Applied Systems Analysis research team led by Julian David Hunt is to pump that cold ocean water to district cooling facilities on land and distribute the chilled air to surrounding residences, office buildings, and commercial structures. Think of it as the opposite of geothermal heating. Obviously, no one is suggesting pumping the water hundreds of miles across burning deserts. But for coastal communities, particularly those on thousands of inhabited islands around the world, the idea may make sense.
The conundrum, of course, is that as the environment gets hotter, the demand for air conditioning increases, which in turn makes the environment hotter still. The answer today is to buy a window air conditioner, pop it into an available window and turn it on. Room A/Cs are cheap but operating them is not. By contrast, SWAC consume far less energy — up to 70% less –making they cost effective in the long run, but the initial costs of building a district cooling system are high. The authors of the research suggest the most likely candidates for SWAC technology are airports, data centers, hotels and resorts, governmental and military facilities, universities, and large commercial buildings. Another possible application would involve using excess renewable energy to freeze the water during periods of low cooling demand so it could be thawed and used later when demand increases.
The technology does have some drawbacks. The researchers prefer to call then challenges. Chief among them is how to re-introduce the now warmed sea water back into the ocean in a way that will not threaten marine life that is used to colder temperatures. “While it does have its challenges, seawater air conditioning is an innovative and sustainable technology that has great potential for expanding into a benchmark system for cooling in tropical locations close to the deep sea and will help fulfill our cooling needs in a warming world,” Julius Hunt concludes, according to a report by Science Daily.
Sequestering Carbon Dioxide Efficiently And Economically
Researchers at the University of Beyreuth in Germany have discovered a new material that can separate and retain carbon dioxide from waste gases, natural gas, or biogas in a fundamentally different way than other carbon capture techniques. The captured carbon dioxide does not bind with other elements and can be released immediately so the medium can be reused to capture more.
Published recently in the journal Cell Reports Physical Science, the research led by Martin Riess say carbon dioxide accumulates in the cavities of the material solely due to physical interaction. From there, it can be released without great expenditure of energy. The separation process works, chemically speaking, according to the principle of physical adsorption. In the labs at Bayreuth University, it was designed to only separate out carbon dioxide and no other gasses.
“Our research team has succeeded in designing a material that fulfills two tasks at the same time. On the one hand, the physical interactions with CO2 are strong enough to free and retain this greenhouse gas from a gas mixture. On the other hand, however, they are weak enough to allow the release of CO2 from the material with only a small amount of energy,” says Riess, according to a report by Science Daily.
So what is this wonder material? It is a clay based organic-inorganic hybrid consisting of hundreds of individual glass plates that are just one nanometer thick and arranged precisely one above the other. Between them are organic molecules that act as spacers whose shape and chemical properties have been selected so the pore spaces between them are optimal for capturing CO2. Methane, nitrogen, and other exhaust gasses are unable to enter those spaces because of the size of their molecules. The researchers are currently working on the development of a membrane system based on these clay minerals that will allow the continuous, selective, and energy efficient separation of CO2 from gas mixtures.
The development of a hybrid material tailor made for the separation and supply of CO2 was made possible by a special measuring system set up in the Bayreuth laboratories which allows the precise determination of quantities of adsorbed gases and of the selectivity of the adsorbing material. This has enabled industrial processes to be reproduced realistically. “All criteria relevant to the evaluation of industrial CO2 separation processes have been completely fulfilled by our hybrid material. It can be produced cost effectively and stands to make an important contribution to reducing industrial carbon dioxide emissions, but also to the processing of biogas and acidic natural gas,” says Riess.
The Take Away
These are but two examples of ways researchers around the world are seeking new technologies to help humanity deal with the issue of an overheating planet. There are hundreds more of them underway. Some will be useless or far too costly to be effective, but some may be just what we need to manage a dangerous situation that affects us all. Time is short and the danger is high. We will need all the help we can get to avoid a climate calamity of unimaginable proportions.
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