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Water-based, energy-saving air-conditioner

1/19/2018

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Just a reminder, Midterm Examinations are approaching for some classes – one previous blog post that may be useful is from 01/04/2015 titled Midterm Examinations.

The book Chemistry on a Budget contains inexpensive chemistry labs that are useful with easy to obtain materials.

 
There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report.  This way the teacher has the option!  Each lab is two pages to allow for one two-sided handout. 
 
A 5-Star Customer Review of Chemistry on a Budget at amazon.com states:
“[S]traight forward, to the point, using household chemicals…this is the lab book for you. 
I teach high school chemistry and this is exactly what [I] was looking for. Labs included simple household chemicals that could be easily found. Nice format, easy to follow along procedures, and touches on every topic of our chemistry curriculum.”
 
 
You can buy this lab book for $23 at amazon.com or lulu.com. It will take 1-2 weeks to get to you -- Order Now.  It’s a great resource!
 
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

http://www.lulu.com/shop/marjorie-r-heesemann/chemistry-on-a-budget/paperback/product-21217600.html
 
*Some of you have already purchased my lab book – be sure to check out Page 141 !
 
“Paul Hawken, the editor of Drawdown, says that air conditioning [AC] contributes a shockingly high amount of atmospheric emissions. The global demand for AC is increasing rapidly thanks to rising economic prosperity in developing countries and higher average temperatures. By 2050, Hawken says hydroflourocarbons, the refrigerants that make air conditioning possible, will account for 19% of all atmospheric emissions. If the world got 21% of its electricity from wind turbines by 2050, the carbon emissions saved would be exceeded by the carbon emissions created to keep us all cool.”
https://cleantechnica.com/2018/01/10/water-based-air-conditioning-slashes-energy-usage-uses-no-refrigerants/
 
“A team of researchers from the National University of Singapore (NUS) has pioneered a new water-based air-conditioning system that cools air to as low as 18 degrees Celsius without the use of energy-intensive compressors and environmentally harmful chemical refrigerants. This game-changing technology could potentially replace the century-old air-cooling principle that is still being used in our modern-day air-conditioners. Suitable for both indoor and outdoor use, the novel system is portable and it can also be customised for all types of weather conditions.”
https://www.sciencedaily.com/releases/2018/01/180108133239.htm
 
A brief history:
“Chlorofluorocarbons (CFCs) are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants. …

Refrigerators in the late 1800s and early 1900s used the toxic gases, ammonia (NH3), methyl chloride (CH3Cl), and sulfur dioxide (SO2), as refrigerants. After a series of fatal accidents in the 1920s when methyl chloride leaked out of refrigerators, a search for a less toxic replacement begun as a collaborative effort of three American corporations- Frigidaire, General Motors, and Du Pont. CFCs were first synthesized in 1928 by Thomas Midgley, Jr. of General Motors, as safer chemicals for refrigerators used in large commercial applications. …

​Whereas CFCs are safe to use in most applications and are inert in the lower atmosphere, they do undergo significant reaction in the upper atmosphere or stratosphere. In 1974, two University of California chemists, Professor F. Sherwood Rowland and Dr. Mario Molina, showed that the CFCs could be a major source of inorganic chlorine in the stratosphere following their photolytic decomposition by UV radiation. In addition, some of the released chlorine would become active in destroying ozone in the stratosphere. …

Ozone absorbs harmful ultraviolet radiation in the wavelengths between 280 and 320 nm of the UV-B band which can cause biological damage in plants and animals. A loss of stratospheric ozone results in more harmful UV-B radiation reaching the Earth's surface. Chlorine released from CFCs destroys ozone in catalytic reactions where 100,000 molecules of ozone can be destroyed per chlorine atom.

A large springtime depletion of stratospheric ozone was getting worse each following year. This ozone loss was described in 1985 by British researcher Joe Farman and his colleagues. It was called ‘the Antarctic ozone hole’ by others. …The need for controlling the CFCs became urgent.

In 1987, 27 nations signed a global environmental treaty, the Montreal Protocol to Reduce Substances that Deplete the Ozone Layer, that had a provision to reduce 1986 production levels of these compounds by 50% before the year 2000.” https://www.esrl.noaa.gov/gmd/hats/publictn/elkins/cfcs.html
 
“For one, air conditioning isn’t so much about ‘destroying’ heat as it is about taking it somewhere else — specifically, out of the room. Comfy on the inside, but the reverse of the coin is that the ‘outside’, especially if you live in a big city, gets much warmer very fast. Le Chatelier’s principle on equilibrium tells us that this will make it progressively more difficult for air conditioning units to actually push all that heat outside: it’s more laborious to create a big imbalance (pumping heat from a cold room to a hot outside) than a small one (say, between two bodies at closer temperatures). It’s like pushing water uphill. Which segues us into issue Mk.2:

The harder our ACs have to work, the more energy they need. Ironically, this makes everything hotter, as that energy degrades into heat. It’ll also put a large dent in many a family’s finances, and many people will have to contend with an unenviable choice: go into overdraft, or gamble that nobody’s going to get heatstroke. Zooming back even further, it will put a huge strain on often aging and already-overtaxed power grids — and we definitely don’t want these to pop when everybody’s hugging the AC for dear life.

Lastly, our current systems employ chemical refrigerants such as chlorofluorocarbons and hydrochlorofluorocarbons for cooling, which are quite nasty for the environment. More directly important to you, however, is that these compounds are quite expensive to manufacture and very deadly if leaks occur indoors.

So we need a better alternative. Luckily for us, that’s exactly what one team of researchers from the National University of Singapore (NUS) has been working on, with support from the Building and Construction Authority and National Research Foundation Singapore. The device they came up with could potentially address the limitations of the century-old AC principle in use today.”
https://www.zmescience.com/science/water-based-air-conditioning/
 
“Led by Associate Professor Ernest Chua from the Department of Mechanical Engineering at NUS Faculty of Engineering, the team's novel air-conditioning system is cost-effective to produce, and it is also more eco-friendly and sustainable. The system consumes about 40 per cent less electricity than current compressor-based air-conditioners used in homes and commercial buildings. This translates into more than 40 per cent reduction in carbon emissions. In addition, it adopts a water-based cooling technology instead of using chemical refrigerants such as chlorofluorocarbon and hydrochlorofluorocarbon for cooling, thus making it safer and more environmentally-friendly.

To add another feather to its eco-friendliness cap, the novel system generates potable drinking water while it cools ambient air.”
https://www.mintselection.com/feed-items/water-based-eco-friendly-and-energy-saving-air-conditioner/
 
“The water-based air conditioner consumes 40.0% less energy than the currently used compressor-based air-conditioners and helps attain a temperature of 18 degree Celsius.”
https://cmfenews.com/new-eco-friendly-air-conditioners-use-water-cooling-agent/
 
Past blog posts related to Thermodynamics include:
 
03/02/2014           Heating and Cooling Curves
03/05/2014           Heat and Energy
03/02/2014           Heating and Cooling Curves
03/04/2015           Calorimetry
01/27/2017           2016 Warmest Year on Record
 
*This Blog contains several entries that would be helpful to your chemistry classroom.  Check out the Topic List to help you to find past Blog entries.
 
Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.
 
Remember, buying a copy of the lab book Chemistry on a Budget can be very useful to your Chemistry classroom with labs and class article ideas.

Have a great weekend!

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    Marjorie R. Heesemann is a chemistry teacher with 15 years of experience who is now working to develop resources for the Chemistry classroom.

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