29% More Energy Efficient Refrigeration With Multi-Walled Carbon Nanotubes

Power consumption of a home refrigerator can be cut by 29% while improving cooling capacity. Researchers replaced widely-used, but environmentally unfriendly, R134a refrigerant with the more energy-efficient R600a. They dosed R600a with multi-walled carbon nanotube (MWCNT) nanoparticles.

A more energy-efficient refrigerant can result in much lower electricity bills. For vulnerable households, energy security can be improved as a result. Improved energy economy and demand-side management can also benefit planners at power utilities, as cooling accounts for about 40% of energy demand.

Energy Reports – Energy performance evaluation of R600a/MWCNT-nanolubricant as a drop-in replacement for R134a in household refrigerator system

Vapour compression refrigerator systems working with R134a are associated with high energy demand and environmental problems and refrigerator consumers’ prioritise energy consumption in choosing their choice of refrigerator systems. Therefore, this research work investigated R600a in MWCNT-nanolubricant (0.4 g/L and 0.6 g/L) as a drop in replacement for R134a refrigerant in a household refrigerator system with varied mass charge of R600a (50, 60 and 70 g). The refrigerator was instrumented at the inlet and outlet of the refrigerator compressor, condenser, expansion valve and evaporator. Two bourdon type pressure gauges were connected to the compressor inlet and outlet of the system. The results were taken and evaluated and compared with the result obtained through R134a refrigerant in the system. The result showed that R600a perform better in terms of COP, power consumption and cooling capacity compared to R134a in the system with lower evaporator temperature of −11 °C and power consumption of 0.0639 kW and highest COP in the system. Therefore, R6000a/MWCNT- nanolubricant can serve as a drop in replacement for R134a in the household refrigerator.

SOURCES- Energy Reports, University of Johannesburg
Written By Brian Wang, Nextbigfuture.com

24 thoughts on “29% More Energy Efficient Refrigeration With Multi-Walled Carbon Nanotubes”

  1. Yeah, that’s why I’ve been looking into rocket mass heaters. They burn so hot there is no smoke or creosote released. Kind of a pain to build, but they can keep your house from freezing for a couple/few days (with decent insulation) at a time if you leave for a weekend or whatever.

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  2. $0.10 a gram if quality doesn’t matter (and I doubt it does in this application). You’d need about an ounce so call it $3

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  3. That’s a little sad, considering the moves towards wood pellet stoves in more recent years, as a heat source.

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  4. I’m saying that this only only shows up in the experimental measurements due to the experiment set-up and incorrect assumptions. On a hot wire heat transfer experiment, of course this shows higher heat transfer, since the depositing particles in essence increase the surface area of the wire, but the calculations don’t take that into consideration, and the calculations of h from heat input and temperatures shows “wow, a 30% increase in heat transfer!” In application it does not lead to something that works as advertised. If all the nano-particles fall out on the heat transfer surface where the liquid is boiling, leaving a crud deposit, then that portion of the loop clogs. Often, in the end, you are much better off just using internal or external fins on your piping/cladding.

    One more strike against these concepts, is that two phase heat transfer fluids are seldom good for pumps and piping. The nano-particles almost never stay in suspension for long in the fluids, before something upsets the balance and the particles start to clump.

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  5. Butane has been used for many years as a back-yard, black market, refrigeration refill liquid. Especially in those locations where regulation of the fluorine based materials is so restricted as to drive a “simple regas” up to hundreds of dollars.

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  6. I’ve actually considered marketing an absorption style air conditioner that would be powered off one of those outside wood furnaces. Wood heat is dirt cheap around here, the problem is that it’s air conditioning that’s needed most of the year.

    Regulatory risk kept me from doing it. Wood burning heat has been under sustained regulatory attack for years now.

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  7. This is possible because R600a is known to save more energy cost than R134a in refrigerator system, therefore, application of R600a/MWCNT -Oil can possibly save much more energy compared to R134a in refrigerator system.

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  8. not this again… Okay, so the “nano-particles” or “nano-tubes” in this case, merely act in the same way as roughening up the surface, they stick to the surface at points, thereby increasing the effective surface area for heat transfer. There is no molecules being distorted by the nano particles, or electronic changes in the molecules caused by the nano particles. This has been tried in the nuclear regime as well. Jacopo (sp?) at MIT looked into this and proved what I said above was happening like 10-15 years ago (nuclear heat transport applications). This was also pursued in ionic fluids for solar thermal applications, but again, nothing showed up cause it turned out it was merely the same effect Jacopo showed. Nano-particles love to stick to surfaces with heat fluxes or phase changes occurring too, just like other junk in fluids (fouling).

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  9. So what does this stuff cost and how is it manufactured? This could be huge or meaningless. Saving 29% through the whole cold chain would be a dramatic change.

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  10. When I was a child some people had kerosene powered fridges. It shouldn’t be difficult to power a fridge using heat from a small solar water heater like unit.

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  11. “I’ve heard all the pickup lines, try me.”
    “Enhanced with nano-technology”
    …this could either be a huge success or a setup for a joke.

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  12. When nanotubes finally break into male enhancement, it’s going to be revolutionary! Here we see a 29% improvement in refrigeration – what more could be improved, enlarged or made just plain better with CNT?

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