A new solar desalination system takes in saltwater and heats it with natural sunlight. The system flushes out accumulated salt, so replacement parts aren’t needed often, meaning the system could potentially produce drinking water that is cheaper than tap water.
MIT engineers and collaborators developed a solar-powered device that avoids salt-clogging issues of other designs.
The researchers estimate that if the system is scaled up to the size of a small suitcase, it could produce about 4 to 6 liters of drinking water per hour and last several years before requiring replacement parts. At this scale and performance, the system could produce drinking water at a rate and price that is cheaper than tap water.
But can it be scaled up even more? Like cubic meters per hour?
I just keep waiting for them to actually produce the small suitcase sized product. It sounds like a excellent option for me, as opposed to the $4-5k desalinators that are the options now.
That's just how research works most of the time. The experimental setup required to build a working prototype and prove the initial hypothesis is always going to be larger and more complex than a mass market appliance. If that appliance ever gets built depends on a huge number of factors too. If the process scales as expected, how complex the device is to produce and if a company thinks that it can make money on it. The researchers, meanwhile, are probably more worried about their next grant funding.
Extreme salt-resisting performance with concentrated seawater
To demonstrate the long-term resistance to salt accumulation enabled by TSMD, we
conducted a 180-h continuous desalination test of 20 wt % concentrated seawater
under 1,000 W m2 (Figures S25 and S26). The corresponding cumulative heat input
was 180 kWh m2 , equal to the total solar irradiance of z45 days. 23 Figure 5A shows
the saline temperature change of a single-stage TSMD device during the 180-h
continuous desalination. The temperature of confined saline layer remained stable
throughout the test, indicating reliable heat transfer performance. Figures 5B and
5C show the mass change of the collected freshwater and the resulting water
Figure 5. Extreme salt-resisting performance of TSMD when desalinating 20 wt % concentrated
seawater
(A) Saline temperature as a function of time. Periodic temperature fluctuations were observed
throughout the test, indicating the existence of strong thermohaline convection.
(B) Real-time mass change of the collected water during the 180-h continuous test.
(C) Water production rate as a function of time. The production rate was averaged with a 10-h time
interval. A stable production rate was maintained throughout the 180-h operation. Error bars
indicate standard deviations.
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production rate during the 180-h continuous desalination. The linear profile of mass
change (Figure 5B) during 180-h operation indicates a stable water production rate
without degradation in performance (Figure 5C). Note that in conventional reliability
tests, a cycling operation was adopted. In each cycle, there was a 3–6 h operation
under one-sun illumination, followed by a 21–18 h waiting period without solar illu-
mination to emulate the nighttime condition and allow the salt rejection (Table S2).
In our reliability test, however, we created a more stringent procedure by performing
a 180-h continuous test and removing all waiting periods. Considering the salinity
(20 wt %) of concentrated seawater used for our test, the total amount of salt rejected
during the 180-h operation is equivalent to the accumulated salt in seawater desa-
lination (3.5 wt %) throughout z229 day cycling operations (Note S3; Table S2).
With the superior salt-resisting capacity, the estimated device lifetime shows 1 order
of magnitude improvement compared with the state-of-the-art designs (Table S2).
The paper is very cool though!! Maybe we are all looking towards a future with plenty of fresh water!