Salty Refrigeration Is Friendly To The Environment

Widespread use of refrigerators is a hallmark of modern society, allowing people to store food and enjoy ice and cold beverages. However, a typical refrigerator uses gasses that are not always good for the environment. Now the Berkeley National Lab says they can change that using ioncaloric cooling, a new technique that uses salt as a refrigerant.

The new technique involves using ions to drive a solid-to-liquid phase change which is endothermic. Unlike some similar proposals, the resulting liquid material would be easy to pump through a heat exchanger. In simple terms, it is the same process as salting a road to change the melting point of ice. In this case, an iodine-sodium salt and an organic solvent combine. Passing current through the material moves ions which changes the material’s melting point. When it melts, it absorbs heat. When it resolidifies, it releases heat.

People often mention how different the world was without electricity. But another modern convenience we tend to take more for granted is refrigeration. Although the University of Glasgow demonstrated an artificial refrigerator as early as 1748, and there were some earlier designs, commercial refrigerators wouldn’t appear until 1834. Home refrigerators wouldn’t be practical until 1918. Before all this, there was a huge market for harvesting ice where it occurs naturally and transporting it to other places for underground storage and distribution. Early refrigerators used toxic gases. Your refrigerator could literally kill you until the development of a safer gas. But even modern gasses are not good for the environment.

The organic solvent used in the demonstration is actually carbon negative, another potential boon to the environment. With one volt of input, the phase change was 25C, which is, according to the post, better than other similar solid phase change systems.

The other related modern tech is air conditioning. It turns out rubber cools down when it changes shape, and you can use that to make a fridge, too.

34 thoughts on “Salty Refrigeration Is Friendly To The Environment

        1. In the laboratory, ethylene carbonate can also be produced from the reaction of urea and ethylene glycol using zinc oxide as a catalyst at a temperature of 150 °C and a pressure of 3 kPa.

          BOTH conditions P and T can be simply reached with compressors and heaters powered on solar and water power or even wind. Your argument is invalid.

          1. (NH2)2CO + HO−CH2CH2−OH → (CH2O)2CO + 2 NH3
            So it consumes the energy intensive urea and produces ammonia as a waste product. Trying to sell it as a benign CO2 sink is insane.

      1. It’s just smart branding… It’s not like people are going to extract CO2 from the atmosphere to produce this compound. So it’s carbon positive like every single chemical process we use today that involves CO2

        1. You could source your CO2 from say fermentation which would also generate ethanol for your biofuel :) It could be using a purified waste product from different process.

          And ultimately the sunlight is extracting the CO2 from the atmosphere that produces the biomass for the fermentation process.

          1. But….profit, if your a business you need to make profit, and even if you make profit the eventual bean counters will eventually want to make more, C0² is fractions of pennies to produce onsite vs C0² recycling(dollars and transportation costs/Diesel fuel) or carbon capture (millions in investment, even more if you do it cleanly). Trouble is is there is a million different easy/cheap ways to make CO², but only a handful of carbon neutral ways to make C0², and all of them are expensive/require large investments or site sharing, or they are not carbon neutral when all facts are considered. Exceptions can happen, but the bean counting community doesn’t like exceptions.

  1. ” With one volt of input, the phase change was 25C” – how much current (amperes) and how much time? How does the product of voltage, current, and time (energy) compare with the energy used in a conventional refrigerator for the same temperature change? Cooling the same content, of course.

    Cool (he, he) idea, but it will have to compete with conventional fridges on energy consumption as well as environmental friendliness to make it in the real world.

      1. From the abstract: “Our experimental results show a coefficient of performance of 30% relative to Carnot and a temperature lift as high as 25°C using a voltage strength of ~0.22 volts”.

          1. As mentioned in the wiki, the COP depends on both upper and lower temperature, and the value typically assigned to commercial heat pumps also depends on a convention about the typical distribution of these temperatures in reality. So, the COP tells you much more about these assumptions than about the heat pump. To overcome this problem, you can put the efficiency of the heat pump in relation to the carnot cycle with the same temperatures, which was obviously done here: the carnot process is about three times better than the described process in rising the temperature by 25K within the measured temperature range.

    1. There seems to be something funny going on there. The publicly available information is too sketchy. Wondering if their prototype was tiny, and if the process doesn’t scale well or something.

      1. PR departments of research facilities are designed to be filters that remove relevant and cautionary information and expand the residue to show how it could save humanity.

    2. Amen. No one needs toilet tissue from recycled paper that doesn’t work well, falls apart, costs more than name brand and can double as 800 grit sandpaper but has a little green halo. Same here.

      Need to show the refrigerator equivalent of heat pump SEER–calories moved versus watts spent.

  2. Liquid salt and electrical charges. So these units will be more expensive due to the requirement of at minimum 316 stainless for the components as the simple copper most units currently use won’t cut it with that.

    1. Fridges are mostly stationary. So in theory at least since the critical criteria is the iodine-sodium is protected from oxygen, water and light why can it not be sealed in opaque (E-UV and UV-C)* glass. Glass is 100% recyclable, and where the heat needs to actually be transferred that the walls could be slightly thinner. I’m sure that a extremely low expansion/contraction glass could be created in the temperature range required for normal refrigeration. One nice feature of glass is it’s insulation properties.

      *Ionic bonds are typically in the range 700-4000 kJ/mol and for photolysis that would correspond to light at frequencies from 170 nm to 29 nm. So mostly in the Ultraviolet C (100–280nm) and Extreme ultraviolet (10–121nm) ranges which is strongly attenuated by normal transparent glass. But maybe add some nickel metal to make the glass dark brown to attenuate even more.

      1. Actually I was thinking that this would be a huge change up for the RV industry, as the fridges in that industry are prone to the chemicals crystalizing and blocking tubes when the RV is off camber. If this stuff doesn’t crystal under the same conditions, it could revolutionize RV fridges. However, they would need to figure out a way for propane to produce the required electricity to make this work.

        1. Ive got two absorbtion fridges which date from the 70’s and they are frequently running when in the car getting bounced around, or off and the same.
          They still work great.
          I read the warnings but its’ never been an issue.
          Maybe they dont make them as good as they used to – you know, cos one one makes anything that really lasts any more, cos no profit in it.

    1. Baking soda (Sodium bicarbonate – NaHCO3) and vinegar (acetic acid – CH₃COOH) makes that crystal, I’m trying to think of the name of it. It is called …. sodium acetate: CH3COONa

  3. I work on Refrigerators for a living. Currently GE branded fridges are moving to Butane as a refrigerant. A typical fridge uses about 45 – 60 grams of R600a (industry name for Butane) These units are very energy efficient.

      1. It’s hardly anything so a leak isn’t a problem vs that gas appliance you have, or the gas in your car’s AC system which is both toxic and flamable.
        Or the 60ltr petrol bomb you drive around in…

      2. You’ll find it as the propellant in a lot of household sprays now. Just don’t do hairspray, foot spray, AND body spray in the same room your AC/barfridge is leaking while you light a candle.

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